Annual report
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1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D. C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended June 30, 2026 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-41655 NioCorp Developments Ltd. (Exact name of registrant as specified in its charter) British Columbia, Canada 98-1262185 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 7000 South Yosemite Street, Suite 115 Centennial, CO (Address of principal executive offices) 80112 (Zip Code) Registrant’s telephone number, including area code: (720) 334-7066 Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Shares, without par value NB The Nasdaq Stock Market LLC Warrants, each exercisable for 1.11829212 Common Shares NIOBW The Nasdaq Stock Market LLC Common Share Purchase Rights N/A The Nasdaq Stock Market LLC Securities registered pursuant to section 12(g) of the Act: None. Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☒ Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Large Accelerated Filer ☐ Accelerated Filer ☐ Non-Accelerated Filer ☒ Smaller Reporting Company ☒ Emerging Growth Company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐ If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒ At December 31, 2025, the aggregate market value of the registrant’s voting and non-voting common equity held by non-affiliates of the registrant was $622.4 million based on the closing sale price as reported on the Nasdaq Stock Market. There were 145,849,630 common shares outstanding on September 25, 2026. DOCUMENTS INCORPORATED BY REFERENCE Not applicable.
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TABLE OF CONTENTS Table of Contents Select Mining Definitions i Mineral Reserves and Resources v Currency v Risk Factors Summary v PART I 1 ITEM 1. BUSINESS 1 Introduction 1 Business Operations 1 Corporate Structure 2 Historical Development of the Business 2 Recent Corporate Events 3 Competitive Business Conditions 4 Cycles 4 Economic Dependence 5 Government Regulation 5 Human Capital 6 Forward-Looking Statements 7 Available Information 9 ITEM 1A. RISK FACTORS 9 Risks Related to Our Business 9 Risks Related to Mining and Development 14 Risks Related to Government Regulation 20 Risks Related to Our Debt 22 Risks Related to the Common Shares 22 ITEM 1B. UNRESOLVED STAFF COMMENTS 25 ITEM 1C. CYBERSECURITY 25 ITEM 2. PROPERTIES 25 ITEM 3. LEGAL PROCEEDINGS 40 ITEM 4. MINE SAFETY DISCLOSURES 40 PART II 41 ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS, AND ISSUER PURCHASES OF EQUITY SECURITIES 41 Market Information 41 Holders 41 Dividends 41 Securities Authorized for Issuance Under Equity Compensation Plans 41 Purchases of Equity Securities by the Company 41 Recent Sales of Unregistered Securities 41 Exchange Controls 41 Certain Canadian Federal Income Tax Considerations for U.S. Residents 41 ITEM 6. RESERVED 43 ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS 44 Summary of Consolidated Financial and Operating Performance 44 Results of Operations 44 Liquidity and Capital Resources 45 Cash Flow Considerations 49 Environmental 50 Forward-Looking Statements 50 Accounting Developments 50 Critical Accounting Estimates and Recent Accounting Pronouncements 50 Other 51
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ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK 52 Interest rate risk 52 Foreign currency exchange risk 52 Commodity price risk 52 ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA 52 ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE. 83 ITEM 9A. CONTROLS AND PROCEDURES 83 ITEM 9B. OTHER INFORMATION 85 ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTION 85 PART III 86 ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE 86 ITEM 11. EXECUTIVE COMPENSATION 91 ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS 100 ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE 102 ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES 104 PART IV 105 ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES 105 ITEM 16. FORM 10–K SUMMARY 109 SIGNATURES 110
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i Select Mining Definitions 2022 S-K 1300 Elk Creek Technical Report Summary A technical report summary for the Elk Creek Project that conforms to S-K 1300 reporting standards, with an effective date of June 30, 2022, originally filed as Exhibit 96.1 to the Company’s Annual Report on Form 10-K for the year ended June 30, 2022. 2026 NI 43-101 Elk Creek Technical Report The CIM-compliant NI 43-101 technical report for the Elk Creek Project with an effective date of August 10, 2026. 2026 S-K 1300 Elk Creek Technical Report Summary A technical report summary for the Elk Creek Project that conforms to S-K 1300 reporting standards, with an effective date of June 30, 2026, filed as Exhibit 96.1 to this Annual Report on Form 10-K and incorporated by reference herein. 2026 Elk Creek Study A pre-feasibility study, completed in 2026, prepared by qualified persons for the Elk Creek Project. carbonatite A type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. CIM Canadian Institute of Mining and Metallurgy. cut-off grade The grade (i.e., the concentration of metal or mineral in rock) that determines the destination of the material during mining. For purposes of establishing “prospects of economic extraction,” the cut-off grade is the grade that distinguishes material deemed to have no economic value (it will not be mined in underground mining or if mined in surface mining, its destination will be the waste dump) from material deemed to have economic value (its ultimate destination during mining will be a processing facility). Other terms used in similar fashion as cut-off grade include net smelter return, pay limit, and break-even stripping ratio. deposit A mineralized body which has been physically delineated by sufficient drilling, trenching, and/or underground work, and found to contain a sufficient average grade of metal or metals to warrant further exploration and/or development expenditures. Such a deposit does not qualify as a commercially mineable ore body or as containing reserves or ore, unless final legal, technical, and economic factors are resolved. development stage issuer An issuer that is engaged in the preparation of mineral reserves for extraction on at least one material property. development stage property A property that has mineral reserves disclosed, pursuant to Regulation S-K 1300, but no material extraction. diamond drilling A type of rotary drilling in which diamond bits are used as the rock-cutting tool to produce a recoverable drill core sample of rock for observation and analysis. dysprosium or Dy The element dysprosium (atomic number 66), a rare-earth element in the lanthanide series. dysprosium oxide The chemical compound composed of dysprosium and oxygen with the formula Dy O economically viable When used in the context of mineral reserve determination, means that the qualified person has determined, using a discounted cash flow analysis, or has otherwise analytically determined, that extraction of the mineral reserve is economically viable under reasonable investment and market assumptions. Elk Creek Project The Company’s critical minerals project located near Elk Creek, Nebraska that is expected to produce niobium, scandium, titanium, and several rare earth products, including neodymium-praseodymium oxide, dysprosium oxide, terbium oxide, SEG carbonate, and heavy rare earth carbonate feasibility study A comprehensive technical and economic study of the selected development option for a mineral project, which includes detailed assessments of all applicable modifying factors, as defined under S-K 1300, together with any other relevant operational factors, and detailed financial analysis that are necessary to demonstrate, at the time of reporting, that extraction is economically viable. The results of the study may serve as the basis for a final decision by a proponent or financial institution to proceed with, or finance, the development of the project. 2 3.
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ii (1)A feasibility study is more comprehensive, and with a higher degree of accuracy, than a pre- feasibility study. It must contain mining, infrastructure, and process designs completed with sufficient rigor to serve as the basis for an investment decision or to support project financing. (2)The confidence level in the results of a feasibility study is higher than the confidence level in the results of a pre-feasibility study. Terms such as full, final, comprehensive, bankable, or definitive feasibility study are equivalent to feasibility study. ferroniobium or FeNb An iron-niobium alloy, with a niobium content of 60-70%. indicated mineral resource That part of a mineral resource for which quantity and grade or quality are estimated on the basis of adequate geological evidence and sampling. The level of geological certainty associated with an indicated mineral resource is sufficient to allow a qualified person to apply modifying factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit. Because an indicated mineral resource has a lower level of confidence than the level of confidence of a measured mineral resource, an indicated mineral resource may only be converted to a probable mineral reserve. inferred mineral resource That part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. The level of geological uncertainty associated with an inferred mineral resource is too high to apply relevant technical and economic factors likely to influence the prospects of economic extraction in a manner useful for evaluation of economic viability. Because an inferred mineral resource has the lowest level of geological confidence of all mineral resources, which prevents the application of the modifying factors in a manner useful for evaluation of economic viability, an inferred mineral resource may not be considered when assessing the economic viability of a mining project, and may not be converted to a mineral reserve. LoM Life of Mine, the period from the beginning of construction to the end of mine life. measured mineral resource That part of a mineral resource for which quantity and grade or quality are estimated on the basis of conclusive geological evidence and sampling. The level of geological certainty associated with a measured mineral resource is sufficient to allow a qualified person to apply modifying factors, as defined in this section, in sufficient detail to support detailed mine planning and final evaluation of the economic viability of the deposit. Because a measured mineral resource has a higher level of confidence than the level of confidence of either an indicated mineral resource or an inferred mineral resource, a measured mineral resource may be converted to a proven mineral reserve or to a probable mineral reserve. mineral reserve An estimate of tonnage and grade or quality of indicated and measured mineral resources that, in the opinion of the qualified person, can be the basis of an economically viable project. More specifically, it is the economically mineable part of a measured or indicated mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined or extracted. mineral resource A concentration or occurrence of material of economic interest in or on the Earth's crust in such form, grade or quality, and quantity that there are reasonable prospects for economic extraction. A mineral resource is a reasonable estimate of mineralization, taking into account relevant factors such as cut-off grade, likely mining dimensions, location or continuity, that, with the assumed and justifiable technical and economic conditions, is likely to, in whole or in part, become economically extractable. It is not merely an inventory of all mineralization drilled or sampled. modifying factors The factors that a qualified person must apply to indicated and measured mineral resources and then evaluate in order to establish the economic viability of mineral reserves. A qualified person must apply and evaluate modifying factors to convert measured and indicated mineral resources to proven and probable mineral reserves. These factors include, but are not restricted to: mining; processing; metallurgical; infrastructure; economic; marketing; legal; environmental compliance; plans, negotiations, or agreements with local individuals or groups; and governmental factors. The number, type and specific characteristics of the modifying factors applied will necessarily be a function of and depend upon the mineral, mine, property, or project.
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iii NI 43-101 National Instrument 43-101 of the Canadian Securities Administrators entitled “Standards of Disclosure for Mineral Projects” niobium or Nb The element niobium (atomic number 41), a transition metal primarily used in the production of high- strength, low-alloy steel NbO Niobium pentoxide, a commercial form of refined niobium neodymium oxide The chemical compound composed of neodymium and oxygen with the formula Nd O NSR Net Smelter Return, the net revenue that the owner of a mining property receives from the sale of the mine's products less transportation and refining costs praseodymium oxide The chemical compound composed of praseodymium and oxygen with the formula Pr O preliminary feasibility study (or pre-feasibility study) A comprehensive study of a range of options for the technical and economic viability of a mineral project that has advanced to a stage where a qualified person has determined (in the case of underground mining) a preferred mining method, or (in the case of surface mining) a pit configuration, and in all cases has determined an effective method of mineral processing and an effective plan to sell the product. (1)A pre-feasibility study includes a financial analysis based on reasonable assumptions, based on appropriate testing, about the modifying factors and the evaluation of any other relevant factors that are sufficient for a qualified person to determine if all or part of the indicated and measured mineral resources may be converted to mineral reserves at the time of reporting. The financial analysis must have the level of detail necessary to demonstrate, at the time of reporting, that extraction is economically viable. (2)A pre-feasibility study is less comprehensive and results in a lower confidence level than a feasibility study. A pre-feasibility study is more comprehensive and results in a higher confidence level than an initial assessment. probable mineral reserve The economically mineable part of an indicated and, in some cases, a measured mineral resource production stage property A property with material extraction of mineral reserves proven mineral reserve The economically mineable part of a measured mineral resource and can only result from conversion of a measured mineral resource qualified person An individual who is: (1)A mineral industry professional with at least five years of relevant experience in the type of mineralization and type of deposit under consideration and in the specific type of activity that person is undertaking on behalf of the registrant; and (2)An eligible member or licensee in good standing of a recognized professional organization at the time the technical report is prepared. For an organization to be a recognized professional organization, it must: (i) Be either: (A)An organization recognized within the mining industry as a reputable professional association; or (B)A board authorized by United States federal, state, or foreign statute to regulate professionals in the mining, geoscience, or related field; (ii)Admit eligible members primarily on the basis of their academic qualifications and experience; (iii)Establish and require compliance with professional standards of competence and ethics; (iv)Require or encourage continuing professional development; (v)Have and apply disciplinary powers, including the power to suspend or expel a member regardless of where the member practices or resides; and (vi)Provide a public list of members in good standing. 2 5 2 3 2 3
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iv rare earth elements, rare earths or REEs A group of 17 elements, primarily the 15 lanthanide elements. Lanthanum, cerium, praseodymium, neodymium and promethium are considered “light” REE; samarium, europium and gadolinium are often referred to as “medium” REE; while terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium are considered “heavy” REE (“HREE”). Two additional elements, yttrium and scandium, are often classified as HREE although they are not lanthanides. Yttrium and scandium are also included in this categorization because they exhibit similar properties to the lanthanides and are found in the same ore bodies. Individual mineral deposits may not contain all REEs in economically recoverable quantities. rare earth products Commercial rare earth products currently being examined for production by the Company, including neodymium-praseodymium oxide (sometimes referred to as didymium oxide), dysprosium oxide, and terbium oxide. These are the primary rare earths compounds used to manufacture the world’s most powerful permanent magnets. relevant experience For purposes of determining whether a party is a qualified person, that the party has experience in the specific type of activity that the person is undertaking on behalf of the registrant. If the qualified person is preparing or supervising the preparation of a technical report concerning exploration results, the relevant experience must be in exploration. If the qualified person is estimating, or supervising the estimation of mineral resources, the relevant experience must be in the estimation, assessment and evaluation of mineral resources and associated technical and economic factors likely to influence the prospect of economic extraction. If the qualified person is estimating, or supervising the estimation of mineral reserves, the relevant experience must be in engineering and other disciplines required for the estimation, assessment, evaluation, and economic extraction of mineral reserves. (1)Relevant experience also means, for purposes of determining whether a party is a qualified person, that the party has experience evaluating the specific type of mineral deposit under consideration (e.g., coal, metal, base metal, industrial mineral, or mineral brine). The type of experience necessary to qualify as relevant is a facts and circumstances determination. For example, experience in a high- nugget, vein-type mineralization such as tin or tungsten would likely be relevant experience for estimating mineral resources for vein-gold mineralization, whereas experience in a low grade disseminated gold deposit likely would not be relevant. Note 1 to Paragraph (1) of the Definition of Relevant Experience: It is not always necessary for a person to have five years' experience in each and every type of deposit in order to be an eligible qualified person if that person has relevant experience in similar deposit types. For example, a person with 20 years' experience in estimating mineral resources for a variety of metalliferous hard- rock deposit types may not require as much as five years of specific experience in porphyry-copper deposits to act as a qualified person. Relevant experience in the other deposit types could count towards the experience in relation to porphyry-copper deposits. (2)For a qualified person providing a technical report for exploration results or mineral resource estimates, relevant experience also requires, in addition to experience in the type of mineralization, sufficient experience with the sampling and analytical techniques, as well as extraction and processing techniques, relevant to the mineral deposit under consideration. Sufficient experience means that level of experience necessary to be able to identify, with substantial confidence, problems that could affect the reliability of data and issues associated with processing. (3)For a qualified person applying the modifying factors, as defined by this section, to convert mineral resources to mineral reserves, relevant experience also requires: (i) Sufficient knowledge and experience in the application of these factors to the mineral deposit under consideration; and (ii)Experience with the geology, geostatistics, mining, extraction, and processing that is applicable to the type of mineral and mining under consideration. S-K 1300 Subpart 1300 of Regulation S-K promulgated by the United States Securities and Exchange Commission
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v scandium or Sc The element scandium (atomic number 21), a transition metal used as an alloying agent with aluminum that provides high strength and lower weight for aerospace industry components and other applications that need lightweight metals. It also is used in the electrolyte layer of solid oxide fuel cells. Sc O Scandium trioxide, the primary form of refined scandium SEG carbonate Samarium-europium-gadolinium carbonate terbium oxide The chemical compound composed of terbium and oxygen with the formula Tb O titanium or Ti The element titanium (atomic number 22), a transition metal which in its oxide form is a common pigment in paper, paint, and plastic. In its metallic form, titanium is used in aerospace applications, armor, chemical processing applications, marine hardware applications, medical implants, power generation, and in sporting goods. TiCl Titanium tetrachloride, an input for the production of high-purity titanium oxides and compounds TiO Titanium dioxide, a commercial form of refined titanium TREO Total Rare Earth Oxides, the sum of all rare earth element oxides in a mineral deposit Mineral Reserves and Resources Information, including all mineral resource and mineral reserve estimates, concerning the Elk Creek Project in this Annual Report on Form 10-K has been prepared in accordance with the requirements of S-K 1300 and is based on the 2026 S-K 1300 Elk Creek Technical Report Summary, filed as Exhibit 96.1 to this Annual Report on Form 10-K. S-K 1300 requires us to disclose our mineral resources, in addition to our mineral reserves, as of the end of our most recently completed fiscal year. You are cautioned that mineral resources are subject to further exploration and development and are subject to additional risks and no assurance can be given that they will eventually convert to future reserves. Inferred resources, in particular, have a great amount of uncertainty as to their existence and their economic and legal feasibility. Investors are cautioned not to assume that any part or all of the inferred resource exists or is economically or legally mineable. In addition, the economic analysis described in the 2026 S-K 1300 Elk Creek Technical Report Summary was conducted in connection with the 2026 Elk Creek Study to demonstrate economic viability and support the determination of mineral reserves and is based on assumptions relating to discount rate, production rates, commodity prices, operating costs, capital expenditures, and other inputs that are subject to significant uncertainty. The results of the economic analysis are not a forecast or prediction of actual results for the periods covered, and actual results may differ materially from those projected by the economic analysis. There can be no assurance that the assumptions underlying the economic analysis will prove to be accurate or that the projected economics of the Elk Creek Project will be realized. See Item 1A., Risk Factors. Currency All dollar amounts in this Annual Report on Form 10-K are expressed in thousands of United States (“U.S.”) dollars unless otherwise indicated. The Company’s accounts are maintained in U.S. dollars and the Company’s consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). Risk Factors Summary Investing in common shares, no par value, of the Company (“Common Shares”) involves numerous risks and uncertainties, as more fully described below. You should read these risks before you invest in our Common Shares. In particular, risks associated with our business include, but are not limited to, the following: Risks Related to Our Business • We will require significant additional capital to fund our business plan. • We have a limited operating history on which to base an evaluation of our business and prospects. • We have a history of losses and expect to continue to incur losses in the future. • We may be unable to successfully negotiate final, definitive offtake agreements, which could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project. 2 3 2 3 4 2
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vi • Any failure of our counterparties to meet their obligations to us or to third parties with respect to our offtake agreements, supply agreements or other commercial agreements could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project. • We may not receive any proceeds from the exercise of our outstanding Common Share purchase warrants (“Warrants”), and the potential adverse effect on the prevailing market prices for our Common Shares as a result of sales, or the perception of future sales, of Common Shares could adversely affect our ability to raise additional capital. • The Company has identified a material weakness in its internal control over financial reporting. If not remediated, the Company’s failure to establish and maintain effective disclosure controls and procedures and internal control over financial reporting could result in material misstatements in its financial statements and a failure to meet its reporting and financial obligations, each of which could have a material adverse effect on the Company’s financial condition and the trading price of the Common Shares. Risks Related to Mining and Development • We face numerous uncertainties in estimating our mineral reserves and resources and inaccuracies in our estimates could result in lower than expected revenues, higher than expected costs and decreased profitability. • Price volatility could have dramatic effects on our results of operations and our ability to obtain financing for the Elk Creek Project and execute our business plan. • The nature of mineral exploration and production activities involves a high degree of risk and the possibility of uninsured losses. • We have no history of producing commercial products from our current mining properties and there can be no assurance that we will successfully establish mining operations or profitably produce minerals. • The success of our business will depend, in part, on the growth of existing and emerging uses for scandium and rare earth products. • Any material changes in mineral resource/reserve estimates and grades of mineralization will affect the economic viability of placing a property into production and a property’s return on capital. • Our properties and operations may be subject to litigation or other claims. • We do not currently insure against all the risks and hazards of mineral exploration, development, and mining operations. Risks Related to Government Regulation • We may not be able to obtain or renew all required permits and licenses to place any of our properties into production. • We are subject to significant governmental regulations that affect our operations and costs of conducting our business. • Land reclamation requirements for our properties may be burdensome and expensive. Risks Related to Our Debt • The level of our indebtedness from time to time could impair our ability to obtain additional financing. Risks Related to the Common Shares • Future sales, or the perception of future sales, of Common Shares by existing shareholders or by us, or future dilutive issuances of Common Shares by us, could adversely affect prevailing market prices for the Common Shares and cause investors to suffer dilution in their net book value per Common Share. • We are subject to the continued listing criteria of The Nasdaq Stock Market LLC (“Nasdaq”) and our failure to satisfy these criteria may result in delisting of the Common Shares. • Our Rights Plan (as defined below) includes terms and conditions that could discourage a take-over or other transaction that shareholders may consider favorable.
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1 PART I ITEM 1. BUSINESS Introduction NioCorp Developments Ltd. (“NioCorp,” “we,” “us,” “our,” or the “Company”) was incorporated under the laws of the Province of British Columbia under the Business Corporations Act (British Columbia) on February 27, 1987, under the name “IPC International Prospector Corp.” On May 22, 1991, we changed our name to “Kingston Resources Ltd.” On June 29, 2001, we changed our name to “Butler Developments Corp.” On February 12, 2009, we changed our name to “Butler Resource Corp.” On March 4, 2010, we changed our name to “Quantum Rare Earth Developments Corp.” On March 4, 2013, we changed our name to “NioCorp Developments Ltd.” NioCorp is a United States Securities and Exchange Commission (“SEC”) reporting company, and we are also a Canadian reporting issuer in British Columbia, Alberta, Saskatchewan, Ontario, and New Brunswick. Our registered and records office is located at 1133 Melville Street, Suite 3500, Vancouver, British Columbia V6E 4E5 (ATTN: Blake, Cassels & Graydon LLP). Our principal executive office is located at 7000 South Yosemite Street, Suite 115, Centennial, Colorado 80112. Business Operations NioCorp, through ECRC (as defined below), is developing a critical minerals project that, if and when developed, will produce niobium, scandium, titanium and several rare earth products, including neodymium-praseodymium oxide, dysprosium oxide, terbium oxide, samarium-europium-gadolinium (“SEG”) carbonate, and heavy rare earth carbonate. Known as the “Elk Creek Project,” it is located near Elk Creek, Nebraska, in the southeast portion of the state. • Niobium is used to produce various superalloys that are extensively used in high performance aircraft and jet turbines. It also is used in high-strength, low-alloy steel, a stronger steel used in automobiles, bridges, structural systems, buildings, pipelines, and other applications that generally enables those applications to be stronger and lighter in mass. This “lightweighting” benefit often results in environmental benefits, including reduced fuel consumption and material usage, which can result in fewer air emissions. • Scandium can be combined with aluminum to make super-high-performance alloys with increased strength and improved corrosion resistance. Scandium also is a critical component of advanced solid oxide fuel cells, which are increasingly being deployed to provide reliable, on-site power for energy-intensive artificial intelligence data centers. • Titanium is a component of various superalloys and other applications that are used for aerospace applications, weapons systems, protective armor, medical implants and many others. It also is used in pigments for paper, paint, and plastics. • Rare earth elements are critical minerals that are needed in virtually all U.S. defense systems and across the electronics, manufacturing, high-technology, transportation, and energy sectors. Magnetic rare earths, such as neodymium, praseodymium, terbium, and dysprosium are critical to the making of neodymium-iron-boron magnets, which are used in critical defense systems, electric vehicles, advanced automation, and robotics. Our primary business strategy is to advance our Elk Creek Project to commercial production. We are focused on securing project financing sufficient to cover initial capital costs and other related expenses necessary for the commencement and completion of construction, and carrying out our near-term planned work programs necessary to complete detailed design, development, and construction of the Elk Creek Project, as well as the commencement of early elements of project construction.
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2 Corporate Structure The Company’s business operations are conducted primarily through ECRC. The table below provides an overview of the Company’s current subsidiaries and their activities: Name State/Province of Formation Ownership Business 0896800 B.C. Ltd. (“0896800”) British Columbia 100% The only business of 0896800 is to hold the shares of Class A common stock of ECRC Elk Creek Resources Corp. (“ECRC”) Delaware 81.33% The business of ECRC is the development of the Elk Creek Project NioCorp Advanced Metals and Alloys, LLC ("NAMA") Delaware 100% The business of NAMA is the production of scandium-containing aluminum master alloys NioCorp Technologies Limited United Kingdom 100% The business of NioCorp Technologies Limited is the research and development of aluminum-scandium alloys and other business opportunities (1) Represents 100% of Class A common stock owned by 0896800, and 3,516,140 Vested Shares and 3,391,596 Earnout Shares (each as defined below) held by third parties, and outstanding as of June 30, 2026. Historical Development of the Business The acquisition of the carbonatite property located in Southeast Nebraska, USA (the “Elk Creek Property”) was closed in December 2010 and involved the purchase by NioCorp of all of the issued and outstanding common shares of a private British Columbia company, which in turn held 100% of the issued and outstanding shares of Elk Creek Resources Corp., a Nebraska corporation. Between 2011 and 2020, the Company advanced the Elk Creek Project through the completion of field exploration programs, feasibility study development and reporting, updates to underground mine designs and supporting infrastructure, and the receipt of required permits from the State of Nebraska. During fiscal year 2021, we obtained funding which allowed us to purchase land and mineral rights at the Elk Creek Property and continue early project execution activities. During fiscal year 2022, we focused efforts towards refining our Elk Creek Project mineral resource and mineral reserve estimates with respect to REEs. This work included additional assays of historical drill core to fill data gaps in the existing resource database and re-modeling. Based on this re-interpretation of the geologic data, an update to the mine plan was also completed. Based on this work, we issued a NI 43-101 technical report on June 28, 2022, and filed the 2022 S-K 1300 Elk Creek Technical Report Summary as an exhibit to our Annual Report on Form 10-K for the year ended June 30, 2022. On March 17, 2023 (the “Closing Date”), the Company closed a series of transactions (the “GXII Transaction”) pursuant to the Business Combination Agreement, dated September 25, 2022 (the “Business Combination Agreement”), among the Company, GX Acquisition Corp. II (“GXII”), and Big Red Merger Sub Ltd (the “Closing”). As a result of the GXII Transaction, among other matters, GXII became an indirect, majority-owned subsidiary of NioCorp and changed its name to “Elk Creek Resources Corp.”, which we refer to as “ECRC,” and the Common Shares and the Warrants that were assumed by NioCorp from GXII (the “NioCorp Assumed Warrants”) were listed for trading on Nasdaq under the symbols “NB” and “NIOBW,” respectively. Pursuant to the Business Combination Agreement, the Sponsor Support Agreement, dated September 25, 2022, among GX Sponsor II LLC (the “Sponsor”), GXII, the Company and the other persons party thereto, and the Exchange Agreement, dated as of March 17, 2023, by and among NioCorp, ECRC and the Sponsor (the “Exchange Agreement”), after the Closing, the shares of Class B common stock of ECRC are exchangeable into Common Shares on a one-for-one basis, subject to certain equitable adjustments, under certain conditions. Of the issued and outstanding shares of Class B common stock of ECRC, 4,565,808 shares (the “Vested Shares”) were vested as of the Closing Date and are exchangeable at any time, and from time to time, until the tenth anniversary of the Closing Date and 3,391,596 shares (the “Earnout Shares”) are exchangeable until the tenth anniversary of the Closing Date, subject to certain vesting conditions. See Note 8 to the consolidated financial statements included in Part II, Item 8 hereof for additional information regarding the Class B common stock of ECRC. In addition, during fiscal year 2026, the Company completed the acquisition of an additional 447.43 acres of land pursuant to existing option to purchase agreements ("OTPs"). As a result of these transactions, the Company now holds full ownership of all surface rights within the one-square-mile section in which it plans to construct both the underground critical minerals (1)
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3 mine and integrated surface processing facility associated with the Elk Creek Project. These acquisitions also include 1.6 acres of land adjacent to Highway 50 and County Road 721 that will be used for improvements to both roadways in order to establish the entrance to the project site on the north side of the Company’s owned lands. On December 4, 2025, the Company, through its newly-formed subsidiary, NAMA, completed the acquisition of the manufacturing assets and intellectual property of FEA Materials LLC for $8.4 million in cash. The acquired assets include equipment and proprietary technology used to produce aluminum-scandium ("Al-Sc") master alloy through an innovative process that converts scandium oxide directly into Al-Sc master alloy, eliminating the need to first manufacture scandium metal. This technology is expected to meaningfully reduce processing complexity and cost relative to traditional methods. The acquisition strengthens the Company’s downstream commercialization strategy by potentially enabling the future production of Al-Sc master alloy in the United States, subject to completion and financing of the Elk Creek Project. On February 26, 2026, the Company announced that construction of the main access to the underground portion (the "Portal Project") of the Elk Creek Project had commenced. The construction of the Elk Creek Project mine’s main entrance, known as a “portal,” will serve as the primary access point for personnel, equipment, and materials, as well as to deliver ore from the underground mine to the surface production plant. The Company also filed a formal “Notice of Commencement” with the Mine Safety and Health Administration ("MSHA") in conjunction with this effort. The Portal Project has an overall budget of $44.6 million, and through June 30, 2026, the Company has incurred approximately $5.6 million in construction costs. During fiscal year 2025, the Company initiated a drilling program at the Elk Creek Project to support the conversion of a portion of its current indicated resources into measured resources and the subsequent conversion of a portion of its current probable mineral reserves into proven mineral reserves. This drilling program and related assay work were completed in fiscal year 2026, and formed the basis of the updated 2026 Elk Creek Study, which is summarized in the 2026 S-K 1300 Elk Creek Technical Report Summary filed as Exhibit 96.1 to this Annual Report on Form 10-K and as more fully described below under Item 2. “Properties.” Recent Corporate Events EXIM Bank Financing Process As previously disclosed, on March 6, 2023, the Company announced the receipt of a Letter of Interest from the Export-Import Bank of the United States (“EXIM”) for potential debt financing, which may include a loan or loan guarantee, through EXIM’s “Make More in America” initiative to fund a portion of the project costs of the Elk Creek Project (the “EXIM Financing”). NioCorp submitted a formal application to EXIM under EXIM’s “Make More in America” initiative on June 6, 2023. The Company was informed that its application received approval by the first of three reviews by the EXIM Transaction Review Committee on October 2, 2023. EXIM deployed additional resources to the processing of the Company’s application during the quarter ended December 31, 2023, and has retained financial and legal consultants to support EXIM’s due diligence on the Elk Creek Project. On April 15, 2024, the Company received a Preliminary Project Letter (the “PPL”) from EXIM. The PPL is a summary of EXIM’s initial due diligence findings and also includes a preliminary Indicative Term Sheet. The PPL identified additional project activities to be undertaken by the Company in conjunction with the EXIM evaluation process. These include an updated mine plan and updated Elk Creek Project capital costs on a final or close-to-final basis reflecting updated process flows. NioCorp continues to work with EXIM to advance the Elk Creek Project through EXIM’s due diligence and loan application process. The completion of the 2026 Elk Creek Study satisfies a key EXIM due diligence requirement reflected in the PPL, and the Company now expects to advance to the next steps of the process relating to detailed engineering, procurement and construction contracting. The PPL included an indicative term sheet, which left open the total estimated amount of the EXIM Financing and provided that the amount of the EXIM Financing that could be made available for the Elk Creek Project will be scaled based on the number of U.S. jobs supported, both during construction and over the life of EXIM’s financing, subject to certain expectations regarding the ratio of debt-to-equity financing for the Elk Creek Project. The Company believes that the updated 2026 Elk Creek Study, with its updated economic analysis, mineral resource and mineral reserve estimates, and increased job creation projections, demonstrates that the Elk Creek Project satisfies the criteria for increased financing as contemplated by the PPL. However, NioCorp is currently unable to estimate the total amount of the EXIM Financing, if any, as well as how long the application process, including additional project activities identified by EXIM, may take, and there can be no assurances that NioCorp will be able to successfully negotiate a final commitment for the EXIM Financing, on acceptable terms, or at all. During the fiscal year ended June 30, 2026, the Company raised approximately $467.2 million in net proceeds from equity financing transactions, which involved the issuance and sale of Common Shares, and pre-funded warrants to purchase Common Shares, in a series of registered offerings. For further discussion, see Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources.”
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4 DoW Agreement On August 4, 2025, ECRC entered into a Project Sub-Agreement (the “DoW Agreement”) with Advanced Technology International, an entity acting on behalf of the Defense Industrial Base Consortium under the authority of the U.S. Department of War (“DoW”). Subject to the terms and conditions of the DoW Agreement, ECRC is entitled to receive up to an aggregate of approximately $10.0 million of reimbursement payments from the DoW upon the achievement of certain project milestones related to engineering and additional reserve drilling, as well as preparing updated cost estimates, for the Elk Creek Project. As of June 30, 2026, NioCorp has received approximately $8.1 million of reimbursement payments under the DoW Agreement. Shareholder Rights Plan Agreement On November 21, 2025, the Company adopted a limited-duration shareholder rights plan (the "Rights Plan") pursuant to a Shareholder Rights Plan Agreement dated November 21, 2025 (the "Original Rights Plan Agreement"), between the Company and Computershare Investor Services Inc., as rights agent (the "Rights Agent"). One right (a "Right") was issued for each Common Share outstanding as of December 4, 2025, and a Right automatically attaches to each Common Share subsequently issued until the expiration of the Rights Plan. The Rights generally become exercisable only if a person or group acquires, or announces the current intention of commencing a take-over bid to acquire, beneficial ownership of 20% or more of the Company's outstanding Common Shares, other than through a permitted bid made in compliance with applicable Canadian take-over bid rules. If the Rights become exercisable, each holder of a Right, other than the acquiring person, would be entitled to purchase additional Common Shares at a discount to the then-current market price. The Rights Plan was not adopted in response to any specific take-over proposal. On April 6, 2026, following approval by the Company's shareholders at the Company's annual general meeting held on April 6, 2026, the Company and the Rights Agent entered into an Amended and Restated Shareholder Rights Plan Agreement (the "Amended Rights Plan Agreement"), which amended and restated the Original Rights Plan Agreement in its entirety. Under the Original Rights Plan Agreement, the Rights Plan would have expired on May 21, 2026. Under the Amended Rights Plan Agreement, the Rights Plan now expires at 5:00 p.m. (Toronto time) on the date of the Company's next annual general meeting. Competitive Business Conditions There is significant competition within the minerals industry to discover, acquire, and obtain project financing for, mineral properties considered to have commercial potential. We compete with others in efforts to obtain project financing and resources to advance the Elk Creek Project to construction and commercial operation, acquire and utilize mining and processing equipment, and hire qualified personnel. These other companies may be better capitalized than us and we may have difficulty in obtaining the financing and resources necessary to advance the Elk Creek Project to construction and commercial operation. There is currently a significant focus on domestic critical mineral supply among potential producers, processors and the U.S. Government. This includes recent government financing and policy support announced for other potential sources of critical minerals, which may alter the strategic importance of the Elk Creek Project and impact our ability to access funding or potential future government support. In addition, in competing for qualified personnel, we may be required to pay compensation or benefits relatively higher than those paid in the past, and the availability of qualified personnel may be limited in high-demand periods. Once the Elk Creek Project begins commercial operation, we expect to face significant competition both domestically and globally for our products. The most prominent global competitor is China, which controls a substantial majority of the world’s scandium and REE production. China’s scandium and rare earth industries benefit from extensive government support, allowing Chinese companies to offer scandium and REEs at subsidized prices, often undercutting other producers. Moreover, Chinese companies have invested heavily in improving their processing capabilities, giving them a technological and cost advantage in the global market, and we believe, at the expense of world sustainability and labor standards. In recent years, China has also begun to implement export controls limiting the amount of scandium and REE products that are sold into the global market outside of China. We believe these controls have created a bifurcated market for scandium, dysprosium and terbium, causing prices outside China to be significantly higher than prices within China. Cycles The mining business is subject to mineral price cycles. The marketability of minerals and mineral concentrates is also affected by worldwide economic cycles. Demand has in the past, and may in the future, be subject to those same worldwide economic cycles. Fluctuations in supply and demand in various regions throughout the world are common. In addition, the niobium, scandium, titanium, and rare earth products, that we intend to produce at the Elk Creek Project are subject to additional commodity-specific price cycles resulting from, among other factors, demand for specific products, export controls, taxes and other tariffs and fees. As NioCorp is a development stage issuer and has not yet generated any revenue from the operation of the Elk Creek Project, it is not currently significantly affected by changes in commodity demand and prices, except to the extent that these changes may impact the development of the Elk Creek Project. As it does not carry on production activities, NioCorp’s ability
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5 to fund ongoing exploration is affected by the availability of financing, which is, in turn, affected by the strength of the economy and other general economic factors. Economic Dependence Other than land and mineral right option agreements and agreements between NioCorp and third parties for the purchase and sale of products to be produced from the Elk Creek Project (“offtake agreements”), NioCorp’s business is not substantially dependent on any contract such as a contract to sell the major part of its product or services or to purchase the major part of its requirements for goods, services or its raw materials, or any franchise or license or other agreement to use a patent, formula, trade secret, process or trade name upon which its business depends. Government Regulation The exploration and development of a mining prospect is subject to regulation by a number of federal and state government authorities. These include the United States Environmental Protection Agency (the “EPA”) and the United States Army Corps of Engineers (the “USACE”) as well as the various state and local environmental protection agencies. The regulations address many environmental issues relating to air, soil, and water contamination, and apply to many mining related activities including exploration, mine construction, mineral extraction, ore milling, water use, waste disposal, and use of toxic substances. In addition, we are subject to regulations relating to labor standards, occupational health and safety, mine safety, general land use, export of minerals, taxation, data protection, and data security. Many of the regulations require permits or licenses to be obtained, the absence of which and/or inability to obtain such permits or licenses will adversely affect our ability to conduct our exploration, development, and operation activities. The failure to comply with the regulations and terms of permits and licenses may result in fines or other penalties or in revocation of a permit or license or loss of a prospect. General While none of the lands on which the Elk Creek Project is proposed to be built are owned by the U.S. Government, mining rights on public lands are governed by the General Mining Law of 1872, as amended, which allows for the location of mining claims on certain federal lands upon the discovery of a valuable mineral deposit and compliance with location requirements. The exploration of mining properties and development and operation of mines is governed by both federal and state laws. Federal laws that govern mining claim location and maintenance and mining operations on federal lands are generally administered by the Bureau of Land Management. Additional federal laws, governing mine safety and health, also apply. State laws also require various permits and approvals before exploration, development or production operations can begin. Among other things, a reclamation plan must typically be prepared and approved, with financial assurance provided in the amount of projected reclamation costs. The financial assurance is used to ensure that proper reclamation takes place and will not be released until that time. Local jurisdictions may also impose permitting requirements, such as conditional use permits or zoning approvals. Environmental Regulation Our mineral projects are subject to various federal, state, and local laws and regulations governing protection of the environment. These laws are continually changing and, in general, are becoming more restrictive. The development, operation, closure, and reclamation of mining projects in the U.S. requires numerous notifications, permits, authorizations, and public agency decisions. Compliance with environmental and related laws and regulations requires us to obtain permits issued by regulatory agencies and to file various reports and keep records of our operations. Certain of these permits require periodic renewal or review of their conditions and may be subject to a public review process during which opposition to our proposed operations may be encountered. We are currently operating under various permits for activities connected to mineral exploration, reclamation, and environmental considerations. Our policy is to conduct business in a way that safeguards public health and the environment. We believe that our operations are conducted in material compliance with applicable laws and regulations. Changes to current local, state, or federal laws and regulations in the jurisdictions where we operate could require additional capital expenditures and increased operating and/or reclamation costs. Although we are unable to predict what additional legislation, if any, might be proposed or enacted, additional regulatory requirements could impact the economics of our projects. Environmental Regulation - U.S. Federal Laws The Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”), and comparable state statutes, impose strict, joint, and several liability on current and former owners and operators of sites and on persons who disposed of or arranged for the disposal of hazardous substances found at such sites. It is not uncommon for the government to file claims requiring clean-up actions and/or demands for reimbursement for government-incurred clean-up costs or natural resource damages. It is also not uncommon for neighboring landowners and other third parties to file claims for personal injury and property damage allegedly caused by hazardous substances released into the environment. The Resource Conservation and
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6 Recovery Act (“RCRA”), and comparable state statutes, govern the disposal of solid waste and hazardous waste and authorize the imposition of substantial fines and penalties for noncompliance, as well as requirements for corrective actions. CERCLA, RCRA, and comparable state statutes can impose liability for clean-up of sites and disposal of substances found on exploration, mining and processing sites long after activities on such sites have been completed. The Clean Air Act, as amended (“CAA”), restricts the emission of air pollutants from many sources, including mining and processing activities. Any future mining operations by the Company may produce air emissions, including fugitive dust and other air pollutants from stationary equipment, storage facilities, and the use of mobile sources such as trucks and heavy construction equipment, which are subject to review, monitoring and/or control requirements under the CAA and state air quality laws. New facilities may be required to obtain permits before work can begin, and existing facilities may be required to incur capital costs in order to remain in compliance. In addition, permitting rules may impose limitations on our production levels or result in additional capital expenditures in order to comply with the rules. The National Environmental Policy Act requires federal agencies to integrate environmental considerations into their decision-making processes by evaluating the environmental impacts of their proposed actions, including issuance of permits to mining facilities and assessing alternatives to those actions. If a proposed action could significantly affect the environment, the agency must prepare either a detailed statement known as an Environmental Impact Statement (“EIS”), or a less detailed statement known as an Environmental Assessment (“EA”). The EPA, other federal agencies, and any interested third parties can review and comment on the scope of the EIS or EA and the adequacy of any findings set forth in the draft and final EIS or EA. This process can cause delays in issuance of required permits or result in changes to a project to mitigate its potential environmental impacts, which can in turn impact the economic feasibility of a proposed project. The Clean Water Act (“CWA”), and comparable state statutes, impose restrictions and controls on the discharge of pollutants into waters of the U.S. The discharge of pollutants into regulated waters is prohibited, except in accordance with the terms of a permit issued by the EPA or an analogous state agency. The CWA regulates storm water from mining facilities and requires a storm water discharge permit or Stormwater Pollution Prevention Plan for certain activities. Such a permit requires the regulated facility to monitor and sample storm water run-off from its operations. The CWA and regulations implemented thereunder also prohibit discharges of dredged and fill material in wetlands and other waters of the U.S. unless authorized by an appropriately issued permit. The CWA and comparable state statutes provide for civil, criminal, and administrative penalties for unauthorized discharges of pollutants, and impose liability on parties responsible for those discharges for the costs of cleaning up any environmental damage caused by the release and for natural resource damages resulting from the release. The Safe Drinking Water Act (“SDWA”) and the Underground Injection Control (“UIC”) program promulgated thereunder, regulate the drilling and operation of subsurface injection wells. The EPA directly administers the UIC program in some states and in others the responsibility for the program has been delegated to the state. The program requires that a permit be obtained before drilling a disposal or injection well. Violation of these regulations and/or contamination of groundwater by mining-related activities may result in fines, penalties, and remediation costs, among other sanctions and liabilities under the SDWA and state laws. In addition, third-party claims may be filed by landowners and other parties claiming damages for alternative water supplies, property damages, and bodily injury. Environmental Regulation − Nebraska Nebraska has a well-developed set of environmental regulations and responsible agencies but does not have clearly defined regulations with respect to permitting mines. As such, review of the project and the issuance of permits by Nebraska agencies and regulatory bodies could potentially impact the total time to market for our Elk Creek Project. Other Nebraska regulations govern operating and design standards for the construction and operation of any source of air emissions and landfill operations. Any changes to these laws and regulations could have an adverse impact on our financial performance and results of operations by, for example, requiring changes to operating conditions, technical criteria, fees, or surety requirements. The most stringent permit related to air quality is known as a Prevention of Significant Deterioration (“PSD”) permit, which requires the applicant to demonstrate compliance with the National Ambient Air Quality Standards ("NAAQS") and Best Available Control Technology (“BACT”) for the control of air emissions. If the facility exceeds the potential to emit thresholds for such a permit and is thus subject to PSD requirements, permanent construction at the project site may not begin until the responsible agency issues the PSD permit. For facilities in Nebraska with potential emissions below PSD thresholds, a state air construction permit is needed. The state permit also requires a demonstration of compliance with NAAQS but does not require a BACT demonstration and further allows construction at a subject facility to proceed ahead of permit issuance through an established variance process. The Elk Creek Project has held a state air construction permit since June 2, 2020. Human Capital The Company’s ability to continue to progress the Elk Creek Project will depend on its ability to attract and retain individuals with (among other skills) financial, administrative, engineering, geological and mining skills, and knowledge of
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7 our industry and targeted markets. Much of the necessary specialized skills and knowledge required by the Company as a mineral exploration company are available from the Company’s current management team and Board of Directors (the “Board”). The Company retains outside consultants if additional specialized skills and knowledge are required. As of June 30, 2026, we had fourteen full-time employees as well as four contract employees. In addition, we use consultants with specific skills to assist with various aspects of our corporate affairs, project evaluation, due diligence, corporate governance, and property management. Our compensation programs are designed to align compensation of our employees with the Company’s performance and to provide the proper incentives to attract, retain, and motivate employees to achieve superior results. The structure of our compensation programs balances competitive wages and benefits and incentive earnings for both short-term and long-term performance. Our priority to maintain a culture of ethical performance as a core value is reflected in the Company’s Code of Business Conduct and Ethics (the “Code of Conduct”) and other related policies. Oversight is provided by the Company’s Board and, for specific areas of performance, by committees of the Board. Employees are required to review the Code of Conduct on a periodic basis. Our compensation programs also include consideration of ethical performance in determining incentive awards. The Company also provides a robust suite of benefits to our employees, including 401(k) participation, medical-insurance options, and programs to encourage and support the whole person. Forward-Looking Statements This Annual Report on Form 10-K and the exhibits attached hereto contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and “forward-looking information” within the meaning of applicable Canadian securities legislation (collectively, “forward-looking statements”). Forward-looking statements have been based upon our current business and operating plans, as approved by the Board, and may include statements regarding, among other matters, the financial and business performance of NioCorp; NioCorp’s anticipated results and developments in the operations of NioCorp in future periods; NioCorp’s planned exploration and development activities; the adequacy of NioCorp’s financial resources; NioCorp’s ability to secure sufficient project financing to complete construction and commence operation of the Elk Creek Project; NioCorp’s expectations on the form of future project financing; the necessity and impact of additional binding offtake agreements and the terms of such agreements, if any; NioCorp’s ability to receive a final commitment of financing from EXIM; future standards imposed by the U.S. federal government, if any; the estimated total upfront capital expenditure for the Elk Creek Project; NioCorp’s expectation and ability to produce niobium, scandium, titanium and the rare earth elements at the Elk Creek Project; NioCorp’s plans to produce and supply specific products and market demand for those products; NioCorp’s expectation that it will receive the full $10.0 million in reimbursement under the DoW Agreement; the intended use of our cash balance as of June 30, 2026, the proceeds from Warrant exercise issuances, and the reimbursement payments pursuant to the DoW Agreement; the Elk Creek Project’s ability to produce multiple critical metals; the Elk Creek Project’s projected ore production and mining operations over its expected mine life; statements with respect to the estimation of mineral resources and mineral reserves; statements with respect to projected product pricing, costs, and project economics; the exercise of options to purchase additional land parcels; the execution of contracts with engineering, procurement and construction companies; NioCorp’s possible future usage of artificial intelligence (“AI”) and the risks and challenges associated therewith; NioCorp’s ongoing evaluation of the impact of inflation, supply chain issues, tariffs, and geopolitical unrest on the Elk Creek Project’s economic model; construction of the Portal Project at the Elk Creek Project; and the creation of full time and contract construction jobs over the construction period of the Elk Creek Project. Forward-looking statements are frequently, but not always, identified by words such as “expects,” “anticipates,” “believes,” “intends,” “estimates,” “potential,” “possible,” and similar expressions, or statements that events, conditions, or results “will,” “may,” “could,” or “should” (or the negative and grammatical variations of any of these terms) occur or be achieved. Any statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, or future events or performance (often, but not always, using words or phrases such as “expects” or “does not expect,” “is expected,” “anticipates” or “does not anticipate,” “plans,” “estimates,” or “intends,” or stating that certain actions, events, or results “may,” “could,” “would,” “might,” or “will” be taken, occur or be achieved) are not statements of historical fact and may be forward-looking statements. Forward-looking statements reflect material expectations and assumptions, including, without limitation, expectations and assumptions relating to: NioCorp’s ability to receive sufficient project financing for the construction of the Elk Creek Project on acceptable terms, or at all; the future price of and demand for metals, including Al-Sc alloy; the impact that Chinese restrictions have on pricing and demand including the existence of a bifurcated market between China and the rest of the world; and the stability of the financial and capital
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8 markets. Such forward-looking statements reflect the Company’s current views with respect to future events and are subject to certain known and unknown risks, uncertainties, and assumptions. Many factors could cause actual results, performance, or achievements to be materially different from any future results, performance, or achievements that may be expressed or implied by such forward-looking statements, including, among others, risks related to the following: NioCorp’s requirement of significant additional capital; NioCorp’s ability to receive sufficient project financing for the construction of the Elk Creek Project on acceptable terms, or at all; NioCorp’s ability to achieve the required milestones and receive the full $10.0 million in reimbursement under the DoW Agreement; NioCorp’s ability to receive a final commitment of financing from EXIM or other debt financing or financial support on acceptable timelines, on acceptable terms, or at all; NioCorp’s ability to continue to meet Nasdaq listing standards; risks relating to the Common Shares, including price volatility, lack of dividend payments and dilution or the perception of the likelihood of any of the foregoing; the extent to which NioCorp’s level of indebtedness and/or the terms contained in agreements governing NioCorp’s indebtedness, if any, or other agreements may impair NioCorp’s ability to obtain additional financing, on acceptable terms, or at all; NioCorp’s limited operating history; NioCorp’s history of losses; the material weakness in NioCorp’s internal control over financial reporting, NioCorp’s efforts to remediate such material weakness and the timing of remediation; the possibility that NioCorp may qualify as a PFIC under the Code; the potential that the 2023 business combination with GXII could result in NioCorp becoming subject to materially adverse U.S. federal income tax consequences as a result of the application of Section 7874 and related sections of the Code; changes in tax laws and regulations; cost increases for NioCorp’s exploration and, if warranted, development projects; a disruption in, or failure of, NioCorp’s information technology systems, including those related to cybersecurity; equipment and supply shortages; variations in the market demand for, and prices of, niobium, scandium, titanium and rare earth products, including, without limitation, a reduction of demand for scandium from a downturn in capital spending for AI; impacts on the markets and pricing for scandium and rare earth products from the Chinese-based markets, including any future changes to export restrictions; current and future offtake agreements, joint ventures, and partnerships, including our ability to negotiate extensions to existing agreements or to enter into new agreements, on favorable terms or at all; NioCorp’s ability to negotiate definitive agreements for existing non-binding memoranda of understanding and non-binding term sheets; NioCorp's ability to attract qualified management; estimates of mineral resources and reserves; mineral exploration and production activities; technical and economic study results; the results of metallurgical testing; the results of technological research; unexpected variations in the quantity of ore, grade or recovery rates, or the presence of deleterious elements that would affect the process plant or waste removal; unexpected geotechnical and hydrogeological conditions from what was assumed in the mine designs; changes in demand for and price of commodities (such as fuel and electricity) and currencies; competition in the mining industry; changes or disruptions in the securities markets; legislative, political or economic developments, including changes in federal and/or state laws that may significantly affect the mining and scandium alloy industries; trade policies and tensions, including tariffs and other export controls; inflationary pressures; the impacts of climate change, as well as actions taken or required by governments related to strengthening resilience in the face of potential impacts from climate change; changes in other environmental and social factors; the need to obtain permits and comply with laws and regulations and other regulatory requirements; the timing and reliability of sampling and assay data; the possibility that actual results of work may differ from projections/expectations or may not realize the perceived potential of NioCorp’s projects; risks of accidents, equipment breakdowns, and labor disputes or other unanticipated difficulties or interruptions; the possibility of cost overruns or unanticipated expenses in development programs; operating or technical difficulties in connection with exploration, mining, development or scandium alloy production activities; management of the water balance at the Elk Creek Project site; land reclamation requirements related to the Elk Creek Project; the speculative nature of mineral exploration and development, including the risks of diminishing quantities or grades of reserves and resources; claims on the title to NioCorp’s properties; the infringement or loss of NioCorp's intellectual property rights; potential future litigation; NioCorp’s lack of insurance covering all of NioCorp’s operations; and changes in operating and capital costs, exchange rates, metallurgical performance, labor availability and other risks associated with the mining industry. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described herein. This list is not exhaustive of the factors that may affect any of the Company’s forward- looking statements. Forward-looking statements are statements about the future and are inherently uncertain, and actual achievements of the Company or other future events or conditions may differ materially from those reflected in the forward-looking statements due to a variety of risks, uncertainties, and other factors, including without limitation those discussed under Item 1A., Risk Factors below. The Company’s forward-looking statements contained in this Annual Report on Form 10-K are based on the beliefs, expectations, and opinions of management as of the date of this Annual Report on Form 10-K. The Company does not assume any obligation to update forward-looking statements if circumstances or management’s beliefs, expectations, or opinions should change, except as required by law. For the reasons set forth above, investors should not attribute undue certainty to, or place undue reliance on, forward-looking statements.
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9 Available Information We maintain a website at http://www.niocorp.com. Our Common Shares are currently registered under Section 12(b) of the Exchange Act, and we are currently required to file reports on Forms 10-K, 10-Q, or 8-K. Our Annual Report on Form 10-K (which includes our audited consolidated financial statements), Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to reports filed or furnished pursuant to Sections 13(a) and 15(d) of the Exchange Act, are available on our website, free of charge, as soon as reasonably practicable after we electronically file such reports with, or furnish those reports to, the SEC. The SEC maintains an internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC (http://www.sec.gov). We do not intend to send security holders a printed version of our Annual Report as it will be available online. We maintain a Code of Conduct, a copy of which may be found on our website in the “About Us” section under the main title “Corporate Governance.” Our Code of Conduct contains information regarding whistleblower procedures. We are not including the information contained on or accessible through our website or the SEC’s website as a part of, or incorporating it by reference into, this Annual Report on Form 10-K. ITEM 1A. RISK FACTORS Our business activities are subject to significant risks, including those described below. You should carefully consider these risks. If any of the described risks occur, our business, financial position, and results of operations could be materially adversely affected. Such risks are not the only ones we face, and additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business. This report contains forward-looking statements that involve risks and uncertainties. Our actual results could differ materially from those anticipated in the forward-looking statements as a result of a number of factors, including the risks described below. See “Forward-Looking Statements” under Item 1., “Business.” Risks Related to Our Business We will require significant additional capital to fund our business plan. We will be required to make substantial capital expenditures to advance the Elk Creek Project to construction and commercial operation. We will also require funds for our ongoing capital needs and will be required to raise additional capital. We expect that the Company will operate at a loss for the foreseeable future. The Company’s current planned cash needs are approximately $65 million to $75 million for the next twelve months. In addition to outstanding accounts payable and short-term liabilities, our planned expenditures over the next twelve months are expected to consist of expenditures relating to the advancement of the Elk Creek Project by NioCorp’s majority owned subsidiary, ECRC, corporate overhead costs, and estimated costs related to securing financing necessary for advancement of the Elk Creek Project. We expect to use our cash balance as of June 30, 2026, as well as the proceeds from Warrant and options to purchase Common Shares ("Options") exercise issuances, and the reimbursement payments pursuant to the DoW Agreement, to fund our planned expenditures for the next twelve months. However, additional work is required in order to advance the Elk Creek Project, which will require additional financing. If the Company were able to obtain additional funding, the Company would be able to accelerate planned expenditures ahead of its current schedule. In addition, to the extent that EXIM requests further project activities to be undertaken in connection with the diligence process, the Company would require additional funding to complete such activities. The Company’s ability to continue operations and fund our current work plan is dependent on management’s ability to secure additional financing. We have not yet commenced commercial production at any of our properties and, as such, have not generated positive cash flows to date and have no reasonable prospects of doing so unless successful commercial production can be achieved at our Elk Creek Project. We expect to continue to incur negative investing and operating cash flows until such time as we enter into successful commercial production. This will require us to deploy our working capital to fund such negative cash flow and to seek additional sources of financing. There is no assurance that any such financing sources will be available or sufficient to meet our requirements. There is no assurance that we will be able to continue to raise equity capital or to secure additional debt financing, or that we will not continue to incur losses. The 2026 S-K 1300 Elk Creek Technical Report Summary includes an estimated total upfront capital expenditure for the Elk Creek Project of approximately $1,849 million. The actual amount of capital expenditure required to successfully achieve commercial production at the Elk Creek Project is subject to, among other factors, the timing and actual cost of further exploration, preparing feasibility studies, permitting, engineering, and the construction of infrastructure, mining and processing
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10 facilities. We anticipate financing the estimated total upfront capital expenditure for the Elk Creek Project with debt financing (including the potential EXIM Financing) and additional equity financing. The potential EXIM Financing is subject to, among other matters, the satisfactory completion of due diligence, including the additional project activities identified in the PPL, the negotiation and settlement of final terms, and the negotiation of definitive documentation. The PPL included an indicative term sheet, which left open the total estimated amount of the EXIM Financing and provided that the amount of the EXIM Financing that could be made available for the Elk Creek Project will be scaled based on the number of U.S. jobs supported, both during construction and over the life of EXIM’s financing, subject to certain expectations regarding the ratio of debt-to-equity financing for the Elk Creek Project. However, NioCorp is currently unable to estimate the total amount of the EXIM Financing, if any, as well as how long the application process, including additional project activities identified by EXIM, may take, and there can be no assurances that NioCorp will be able to successfully negotiate a final commitment for the EXIM Financing, on acceptable terms, or at all. Agreements we enter into may contain restrictions on our ability to raise additional financing on reasonable terms or at all. For example, pursuant to the Exchange Agreement, NioCorp is restricted from issuing equity or equity-linked securities (other than Common Shares) or any preferred equity or non-voting equity if such issuance would adversely impact the rights of the holders of the shares of Class B common stock of ECRC, without the consent of the holders of a majority of the shares of Class B common stock of ECRC. Additionally, sales of substantial amounts of securities may have a highly dilutive effect on our ownership or share structure. Sales of a large number of Common Shares in the public markets, or the potential for such sales, could decrease the trading price of the Common Shares and could impair our ability to raise capital through future sales of Common Shares. There is significant uncertainty that we will be able to secure any additional financing in the current equity or debt markets. Our ability to obtain necessary funding depends upon a number of factors, including, without limitation, the status of the national and worldwide economy, including international trade restrictions and policies, the demand for and the price of the products we intend to produce and our ability to negotiate satisfactory offtake arrangements for the products we intend to produce at the Elk Creek Project. We are actively pursuing additional sources of debt and equity financing, and while we have been successful in doing so in the past, there can be no assurance we will be able to obtain any such additional financing on acceptable terms, if at all. Our inability to access sufficient capital for our operations and the Elk Creek Project could have a material adverse effect on our financial condition, results of operations, or prospects. We have a limited operating history on which to base an evaluation of our business and prospects. Since our inception, we have had no revenue from operations. We have no history of producing products from any of our properties, and our assumptions related to the risks we may face in the future related to the Elk Creek Project may change. Our Elk Creek Project is a development stage property. Advancing our Elk Creek Project from a development stage property to a production stage property will require significant capital and time, and successful commercial production from the Elk Creek Property will be subject to permitting and construction of the mine, processing plants, roads, and other related works and infrastructure. As a result, we are subject to all of the risks associated with developing and establishing new mining operations and business enterprises including: • the timing and cost, which can be considerable, of further exploration, preparing feasibility studies, permitting, engineering and construction of infrastructure, mining, and processing facilities; • the availability and costs of drilling equipment, exploration personnel, skilled labor, and mining and processing equipment, if required; • the availability and cost of appropriate smelting and/or refining arrangements, if required; • compliance with environmental and other governmental approval and permit requirements; • the availability of funds to finance exploration, development, permitting, and construction activities, as warranted; • potential opposition from non-governmental organizations, local groups, or local residents that may delay or prevent development activities; • potential increases in exploration, construction, and operating costs due to changes in the cost of fuel, power, materials, supplies or the encountering of unexpected conditions; and • potential shortages of mining, mineral processing, hydrometallurgical, pyrometallurgical, construction, and other facilities-related supplies. The costs, timing, and complexities of exploration, development, engineering, and construction activities may be increased by the location of our properties and competition from other mineral exploration and mining companies. It is common for
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11 exploration companies to experience unexpected problems and delays during development, if commenced, including engineering, procurement, construction, commissioning, and ramp-up delays. Accordingly, our activities may not result in profitable operations and we may not succeed in establishing operations or profitably producing products at any of our current or future properties, including our Elk Creek Project. We have a history of losses and expect to continue to incur losses in the future. We have incurred losses since inception, have negative cash flow from operating activities, and expect to continue to incur losses in the future. We incurred a net loss attributable to the Company of $48.6 million for the year ended June 30, 2026, and $17.4 million for the year ended June 30, 2025. We expect to continue to incur losses unless and until such time as one of our properties enters into commercial production and generates sufficient revenues to fund continuing operations. We recognize that if we are unable to generate significant revenues from operations and dispositions of our properties, we will not be able to earn profits or continue operations. At this early stage of our operation, we also expect to face the risks, uncertainties, expenses, and difficulties frequently encountered by companies at the start-up stage of their business development. We cannot be sure that we will be successful in addressing these risks and uncertainties and our failure to do so could have a materially adverse effect on our financial condition. Increased costs could affect our financial condition. We anticipate that costs at our projects that we may explore or develop, including the Elk Creek Project, will frequently be subject to variation from one year to the next due to a number of factors, such as changing ore grade, metallurgical performance, and revisions to mine plans, if any, in response to the physical shape and location of the ore body. In addition, costs are affected by the price of commodities such as fuel, steel, aluminum, iron, chemicals, natural gas, fresh water, and electricity, as well as by government actions such as tariffs. Such commodities are at times subject to volatile price movements, including increases that could make production at certain operations less profitable or not profitable at all. For example, the 2026 S-K 1300 Elk Creek Technical Report Summary includes an estimated total upfront capital expenditure for the Elk Creek Project of approximately $1,849 million, including a contingency of 14%, which is an increase of approximately $708 million compared to the estimated total upfront capital expenditure for the Elk Creek Project of approximately $1,141.0 million that was included in the 2022 S-K 1300 Elk Creek Technical Report Summary. The increase in estimated total upfront capital expenditure for the Elk Creek Project is primarily driven by a substantially redesigned processing plan and mining operation producing eight critical minerals and significant inflationary impacts since the 2022 S-K 1300 Elk Creek Technical Report Summary. The actual amount of capital expenditure required to successfully achieve commercial production at the Elk Creek Project is subject to, among other factors, the timing and actual cost of further exploration, preparing feasibility studies, permitting, engineering and the construction of infrastructure, mining, and processing facilities. A material increase in costs at any significant location could have a significant effect on our profitability. We may be unable to successfully negotiate final, definitive offtake agreements, which could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project. We have entered into offtake agreements related to our Elk Creek Project, that cover the sale of 75% of our planned ferroniobium production for the first ten years of commercial operation. We expect that we will need to enter into additional offtake agreements to obtain sufficient project financing to cover initial capital costs and other related expenses, and to establish the commercial viability of the Elk Creek Project. We have entered into non-binding memoranda of understanding and non-binding term sheets related to the offtake of the remainder of the ferroniobium, as well as portions of our expected production of scandium and 100% of our titanium and rare earth production, that we expect to produce from the Elk Creek Project for the first ten years of commercial operation. We may be unable to negotiate final terms and agreements with these or other companies in a timely manner, or at all, and there is no guarantee that the terms of any final agreement will be the same or similar to those currently contemplated. Final terms may include less favorable pricing structures or volume commitments, reduced contract durations and other adverse changes. Delays in negotiating final agreements could slow our initial commercialization, and failure to agree to definitive terms for sales of sufficient volumes of our products could prevent us from growing our business. To the extent that terms in our initial purchase and offtake agreements may influence negotiations regarding future contracts, the failure to negotiate favorable final terms in respect of our current negotiations could have a material negative impact on our growth and profitability. Further, our prospective counterparties may cancel or delay entering into definitive agreements for a variety of reasons, some of which may be outside of our control. Any failure to enter into such definitive agreements on a timely basis, on favorable terms, or at all, could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project.
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12 Any failure of our counterparties to meet their obligations to us or to third parties with respect to our offtake agreements, supply agreements or other commercial agreements could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project. We have entered into offtake agreements, and may enter into joint ventures or partnership arrangements, including additional offtake agreements, with other parties in relation to the exploration, development, and production of certain of the properties in which we have an interest. In addition, we expect to enter into other agreements, including Engineering, Procurement, and Construction (“EPC”) agreements, as well as agreements related to the supply of natural gas and electricity to the Elk Creek Project. Any failure of our counterparties to meet their obligations to us or to third parties, or any disputes with respect to the parties’ respective rights and obligations, price fluctuations and termination provisions related to such agreements, or our ability to negotiate extensions to existing agreements or to enter into new agreements, on favorable terms or at all, could have a material adverse effect on us, the development and production at our properties, including the Elk Creek Project, the joint ventures, if any, or their properties and therefore could have a material adverse effect on our ability to secure project financing and establish the commercial viability of the Elk Creek Project. A disruption in, or failure of our third-party service providers’ IT systems, including those related to cybersecurity, could adversely affect our business operations and financial performance. We rely on the accuracy, capacity, and security of our third-party service providers’ IT systems for the operations of many of our business processes and to comply with regulatory, legal, and tax requirements. We are dependent on third parties to provide important IT services relating to, among other things, operational technology at our facilities, human resources, electronic communications, and certain finance functions. Despite the security measures that our third-party service providers have implemented, including those related to cybersecurity, we have experienced, and may experience in the future, cybersecurity incidents. Cybersecurity incidents and similar attacks vary in their form and can include the deployment of harmful malware or ransomware, denial-of-service attacks, and other attacks, which may affect business continuity and threaten the availability, confidentiality and integrity of our systems and information, and the systems and information of our third-party service providers. Cybersecurity incidents can also include employee or personnel failures, fraud, phishing or other social engineering attempts or other methods to cause confidential information, payments, account access or access credentials, or other data to be transmitted to an unintended recipient. Cybersecurity threat actors also may attempt to exploit vulnerabilities in software that is commonly used by companies in cloud-based services and bundled software. We have experienced cybersecurity threats and cybersecurity incidents in the past, and may experience cybersecurity threats and cybersecurity incidents in the future. To date, we have not identified any risks from cybersecurity threats, including as a result of previous cybersecurity incidents, that have had or are reasonably likely to have, a material impact on our business operations or financial condition. Though our third-party service providers have controls in place, we cannot provide assurance that a cybersecurity incident will not occur in the future. Furthermore, we may have little or no oversight with respect to security measures employed by third-party service providers, which may ultimately prove to be ineffective at countering threats. Cybersecurity threats or incidents or disruptions of our third- party service providers’ IT systems could interrupt our ability to manage and operate our business, impact data, and adversely affect our business operations and financial performance, including major disruptions to business operations, loss of intellectual property, release of confidential information, alteration or corruption of data or systems, costs related to remediation or the payment of ransom, and litigation including individual claims or consumer class actions, commercial litigation, administrative, and civil or criminal investigations or actions, regulatory intervention and sanctions or fines, investigation and remediation costs and possible prolonged negative publicity. In addition, we have incurred costs in connection with the remediation of cybersecurity incidents in the past and we may be required to incur significant costs to protect against and, if required, remediate the damage caused by cybersecurity incidents, disruptions or system failures in the future. We may also be required to comply with cybersecurity standards imposed by the U.S. Government as a condition of entering into government contracts or receiving federal financial assistance. Any failure to comply with these standards, whether or not resulting in a cybersecurity incident or disruption, could restrict our ability to receive financing from the U.S. Government or to bid for, be awarded and perform contracts with the U.S. Government. A shortage of equipment and supplies could adversely affect our ability to operate our business. We are dependent on various supplies and equipment to carry out our mining exploration and, if warranted, project development operations. The shortage of such supplies, equipment, and parts could have a material adverse effect on our ability to carry out our operations and could therefore limit, or increase the cost of, production. Ongoing disruptions to the world’s economy, including issues related to supply chains, inflation, tariffs and trade tensions, and increased raw material and labor costs, may delay our ability to secure supplies and equipment for the Elk Creek Project on a timely basis.
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13 We may use AI in our business, and challenges with properly managing its use could result in reputational harm, competitive harm and legal liability, and could have adverse effects on our results of operations, financial condition, liquidity and cash flows. We may incorporate AI solutions into our business, and we may leverage AI, including generative and agentic AI, into our business operations. Our competitors or other third parties, may incorporate AI into their business more quickly or more successfully than we do, which could impair our ability to compete effectively and could adversely affect our results of operations. In addition, there are significant risks in using AI, and there can be no assurance that the use of AI will enhance our business or be beneficial to our business operations, including our efficiency or our profitability. Additionally, if our AI applications, or the AI applications of third parties, are based on data, algorithms or other inputs that are flawed, or if our AI applications, or the AI applications of third parties, assist us in producing content, analyses or recommendations that are, or are alleged to be, deficient, inaccurate or biased, our business, results of operations and financial conditions may be adversely affected. The increased use of AI applications generally has resulted in, and may in the future result in, cybersecurity incidents that implicate the personal data of end users of such applications. Any such cybersecurity incidents related to our own use of AI applications may increase our cybersecurity risks, as well as the cybersecurity risks of third parties, which could adversely affect our reputation and results of operations. AI also presents emerging ethical issues, and if our use of AI becomes controversial, we may experience brand, reputational or competitive harm, or legal liability. The rapid evolution of AI, including the potential regulation of AI by governmental or other regulatory agencies, will require significant resources to develop, test and implement AI ethically and to minimize any unintended, harmful impacts. We may experience difficulty attracting and retaining qualified management to meet the needs of our anticipated growth, and the failure to manage our growth effectively could have a material adverse effect on our business and financial condition. We are dependent on a relatively small number of key employees, including our Chief Executive Officer. The loss of any officer could have an adverse effect on us. We have no life insurance on any individual, and we may be unable to hire a suitable replacement for them on favorable terms, should that become necessary. Further, the specialized nature of our model as summarized in the 2026 S-K 1300 Elk Creek Technical Report Summary may make qualified persons difficult to replace, which could have a material adverse effect on our business and financial condition. The effect on the capital markets and the economy of recent global events, including inflation, volatility in commodity prices, supply chain uncertainty, tariffs and trade tensions, and increases in raw material and labor costs, could have an adverse effect on NioCorp’s business plans, financial condition, and liquidity. Certain events have affected, and continue to affect, the global and United States economies, including increased inflation, volatility in commodity prices, supply chain uncertainty, tariffs and trade tensions, and increases in raw material and labor costs. We cannot predict how this will affect our business, but the impact may be adverse. Although it is not possible to predict the ultimate impact of these factors on NioCorp’s business plans, financial position, or liquidity, such impacts that may be material include, but are not limited to: (i) delays in the completion of the mine and surface engineering designs and uncertainty regarding our ability to finalize necessary EPC agreements as a result of disruptions in the businesses of our engineering consultants and key contractors for the Elk Creek Project, (ii) reduced availability and increased costs of employees, (iii) a negative impact on our liquidity position, and (iv) increased costs and less ability to access funds in the capital markets. The full extent to which these factors may continue to impact our business will depend on future developments, which continue to be highly uncertain and cannot be predicted at this time. In addition, we cannot predict the impact that recent global events, including inflation, volatility in commodity prices, supply chain uncertainty, tariffs and trade tensions, and increases in raw material and labor costs will have on our customers, suppliers, vendors, and other business partners, and each of their financial conditions; however, any material effect on these parties could adversely impact us. It may be difficult to enforce judgments or bring actions outside the U.S. against us and certain of our directors. We are a Canadian corporation and, as a result, it may be difficult or impossible for an investor to do the following: • enforce in courts outside the U.S. judgments obtained in U.S. courts based upon the civil liability provisions of U.S. federal securities laws against these persons and the Company; or • bring in courts outside the U.S. an original action to enforce liabilities based upon U.S. federal securities laws against these persons and the Company.
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14 We may not receive any proceeds from the exercise of our outstanding Warrants, and the potential adverse effect on the prevailing market prices for our Common Shares as a result of sales, or the perception of future sales, of Common Shares could adversely affect our ability to raise additional capital. Upon exercise, we will receive the cash exercise price of our outstanding Warrants (assuming, that they are not exercised on a cashless basis, as applicable). We believe the likelihood that holders will exercise their Warrants, and therefore, the amount of cash proceeds that we would receive, is, among other things, dependent upon the market price of our Common Shares. For so long as the market price for our Common Shares is less than the applicable exercise price of the Warrants, we believe such holders will be unlikely to exercise their Warrants. The potential adverse effect on the prevailing market price of our Common Shares as a result of sales of Common Shares by us or by other security holders, or the perception that such sales may occur, could keep the market price for our Common Shares below the applicable exercise price of the Warrants. Accordingly, the holders of the Warrants may not exercise their Warrants before they expire, and we may not receive any proceeds from the exercise of the outstanding Warrants. We may not recognize the full value of the DoW Agreement. Subject to the terms and conditions of the DoW Agreement, the DoW will reimburse ECRC for a portion of the costs incurred by ECRC under the DoW Agreement and ECRC is entitled to receive up to an aggregate of approximately $10.0 million of reimbursement payments from the DoW upon the achievement of certain project milestones. If the Company is not successful in achieving the milestones required under the DoW Agreement or if the reimbursements sought by the Company are rejected or the DoW Agreement is terminated prior to completion of all milestones, the Company may not receive all of the payments as reimbursements for expenses incurred as expected under the DoW Agreement. The Company has identified a material weakness in its internal control over financial reporting. If not remediated, the Company’s failure to establish and maintain effective disclosure controls and procedures and internal control over financial reporting could result in material misstatements in its financial statements and a failure to meet its reporting and financial obligations, each of which could have a material adverse effect on the Company’s financial condition and the trading price of the Common Shares. Our management has identified a material weakness in its internal control over financial reporting relating to a deficiency in the principles associated with the control activities component of internal control based on the criteria established by the COSO Framework (as defined below), that constitute a material weakness. A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of a company’s annual or interim financial statements will not be prevented or detected on a timely basis. As discussed in Item 9A, “Controls and Procedures,” of this Annual Report on Form 10-K, the Company’s management has assessed the effectiveness of its internal control over financial reporting and its disclosure controls and procedures and concluded that they were not effective as of June 30, 2026. The Company is committed to remediating its material weakness as promptly as possible. Management is in the process of implementing its remediation plan. However, there can be no assurance as to when the material weakness will be remediated or that additional material weaknesses will not arise in the future. If the Company is unable to maintain effective internal control over financial reporting, its ability to record, process and report financial information timely and accurately could be adversely affected, which could subject the Company to litigation or investigations, require management resources, increase costs, negatively affect investor confidence and adversely impact the trading price of the Common Shares. We may face litigation and other risks as a result of the material weakness in our internal control over financial reporting. We identified a material weakness in our internal control over financial reporting that existed as of June 30, 2026. As a result of such material weakness and other matters raised or that may in the future be raised by the SEC or the Canadian securities regulators, we face potential for litigation or other disputes, which may include, among others, claims invoking the federal and state securities laws, contractual claims or other claims arising from the material weakness in our internal control over financial reporting and the preparation of our financial statements. As of the date of this Annual Report on Form 10-K, we have no knowledge of any such litigation or dispute. However, we can provide no assurance that such litigation or dispute will not arise in the future. Any such litigation or dispute, whether successful or not, could adversely affect our business, financial condition and results of operations. Risks Related to Mining and Development We face numerous uncertainties in estimating our mineral reserves and resources and inaccuracies in, or changes to, our estimates or the factors and assumptions on which they are based, including with respect to the economic analysis conducted
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15 in connection with the 2026 S-K 1300 Elk Creek Technical Report Summary, could result in lower than expected revenues, higher than expected costs, and decreased profitability. A mineral is economically recoverable when the price at which we may sell the mineral exceeds the costs and expenses of mining and selling the mineral. Forecasts of our future performance are based on, among other things, estimates of our mineral reserves. We base our reserve and resource information on engineering, economic, and geological data assembled and analyzed by qualified persons, which include various engineers and geologists on our staff and with third parties. Our estimates are also subject to SEC regulations regarding classification of reserves and resources, including S-K 1300. Our reserve and resource estimates as to both quantity and quality are updated from time to time to reflect additional information received. There are numerous uncertainties inherent in estimating quantities and qualities of mineral reserves and resources, including many factors beyond our control. Estimates of mineral reserves and resources necessarily depend upon a number of variable factors and assumptions, any one of which may, if incorrect, result in an estimate that varies considerably from actual results. These factors and assumptions include, but are not limited to: • geologic and mining conditions, which may not be fully identified by available exploration data and may differ from our experience; • demand for the minerals that we plan to produce; • current and future market prices for minerals and contractual arrangements; • current and future operating costs and capital expenditures may exceed estimates; • severance and excise taxes, royalties and development and reclamation costs; • future mining technology improvements; • the effects of regulation by governmental agencies; • the ability to obtain, maintain and renew all required permits; • employee health and safety; and • historical production from the area compared with production from other producing areas. The conversion of reported mineral resources to mineral reserves should not be assumed, and the reclassification of reported mineral resources from lower to higher levels of geological confidence should not be assumed. As such, actual mineral tonnage recovered from identified reserves, and revenues and expenditures with respect to our reserves, may vary materially from estimates. Thus, these estimates may not accurately reflect our actual reserves. Any material inaccuracy in, or changes to, our estimates related to our reserves, or the underlying factors and assumptions, could result in lower-than-expected revenues, higher-than-expected costs, or decreased profitability, which could materially and adversely affect our business, results of operations, financial position, and cash flows. In addition, the economic analysis described in the 2026 S-K 1300 Elk Creek Technical Report Summary that was conducted in connection with the 2026 Elk Creek Study to demonstrate economic viability and support the determination of mineral reserves may be impacted by the variables listed above, as well as assumptions relating to discount rates, future production rates, commodity prices, operating costs, capital expenditures, and other inputs that are subject to significant uncertainty. For example, the initial capital cost estimate for the Elk Creek Project as described in the 2026 S-K 1300 Elk Creek Technical Report Summary has a contingency level of 14%. The results of the economic analysis are not a forecast or prediction of actual results for the periods covered, and actual results may differ materially from those projected by the economic analysis. There can be no assurance that the assumptions underlying the economic analysis will prove to be accurate or that the projected economics of the Elk Creek Project will be realized. Any material inaccuracy in, or change to, our estimates related to our economic analysis could result in lower than expected revenues, higher than expected costs, or decreased profitability, which could materially and adversely affect our business, results of operations, financial position, and cash flows. Price volatility could have dramatic effects on our results of operations and our ability to obtain financing for the Elk Creek Project and execute our business plan. The price of commodities varies on a daily basis. Niobium is a specialty metal and not a commonly traded commodity such as copper, zinc, gold, or iron ore. The price of niobium tends to be set through a limited long-term offtake market, contracted between very few suppliers and purchasers. The world’s largest supplier of niobium, Companhia Brasileira de Metalurgia e Mineração, supplies approximately 85% of the world’s niobium. Any attempt to suppress the price of niobium by such supplier, or an increase in production by any supplier in excess of any increased demand, would have negative
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16 consequences on the price of niobium and, potentially, on our value. The price of niobium may also be reduced by the discovery of new niobium deposits, which could not only increase the overall supply of niobium (causing downward pressure on its price) but could draw new firms into the niobium industry that would compete with us. Sc2O3 is used in solid oxide fuel cells and has the potential to become a valuable alloy with aluminum in the aerospace and automotive industries. Supply of scandium has been sporadic in recent years, and there are no primary scandium mines in the world at present. Production primarily occurs as a by-product from existing metallurgical plants, primarily in Russia, Canada, the Philippines, and China. Our management believes the Elk Creek Project would significantly increase the world’s supply of scandium trioxide. Although the Company’s market studies indicate a positive outlook for demand, there is no assurance at present that the Company could sell all of its production. In addition, the sale of scandium represents a significant portion of the Elk Creek Project revenue; achieving the revenue projected in the Company’s studies is subject to market growth in scandium, which is a developing market with a risk of oversupply and/or undersupply disrupting pricing. Titanium metal is used in various superalloys and other applications for aerospace applications, armor, and medical implants, and in oxide form is a key component of pigments used in paper, paint, and plastics. The Elk Creek Project would produce a small quantity of TiCl4 relative to other producers. As a small producer, we would be subject to fluctuations in the price of TiCl4 that would result from normal variations in supply and demand for this commodity. In addition, the niobium, scandium, titanium, neodymium-praseodymium oxide, dysprosium oxide, terbium oxide, SEG carbonate and heavy rare earth carbonate, that we intend to produce at the Elk Creek Project are also subject to additional commodity-specific price cycles resulting from, among other factors, export controls, taxes and other tariffs and fees. Volatility in the demand for, and prices of, the niobium, scandium, titanium, and potentially, rare earth products, that we intend to produce at the Elk Creek Project may adversely affect the overall value of the Elk Creek Project and impact our ability to obtain financing for the Elk Creek Project on acceptable terms, or at all. Furthermore, supply-side factors have a significant influence on price volatility for our planned products. Production of scandium and REEs is dominated by Chinese producers. The Chinese Central Government regulates production through quotas and environmental standards and, to a lesser extent, import regulation. It has changed, and may continue to change, those production quotas, environmental standards and import regulations. Over the past few years, the Chinese market has undergone significant restructuring in line with Chinese Central Government policy. However, periods of oversupply or speculative trading in scandium and REEs can lead to significant fluctuations in the market prices of these products. In recent years, China has also begun to implement export controls. We believe these controls have created a bifurcated market for scandium, dysprosium and terbium, causing prices outside China to be significantly higher than prices within China. Any easing of these export controls by China, or the development of alternative sources of supply, could have a material adverse effect on our business, financial condition and results of operations. The nature of mineral exploration and production activities involves a high degree of risk and the possibility of uninsured losses. Exploration for and the production of minerals is highly speculative and involves much greater risk than many other businesses. Most exploration programs do not result in the discovery of mineralization, and any mineralization discovered may not be of sufficient quantity or quality to be profitably mined. Our operations are, and any future development or mining operations we may conduct will be, subject to all of the operating hazards and risks normally incident to exploring for and developing mineral properties, such as, but not limited to: • economically insufficient mineralized material; • fluctuation in production costs that make production uneconomical; • labor disputes; • unanticipated variations in grade and other geologic problems; • environmental hazards; • water conditions; • difficult surface or underground conditions; • industrial accidents; • metallurgical, pyrometallurgical, and other processing problems; • mechanical and equipment performance problems;
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17 • failure of dams, stockpiles, wastewater transportation systems, or impoundments; • unusual or unexpected rock formations; and • personal injury, fire, flooding, cave-ins, and landslides. Any of these risks can materially and adversely affect, among other things, the development of properties, production quantities and rates, costs and expenditures, potential revenues, and production dates. We currently have very limited insurance to guard against some of these risks. If we determine that capitalized costs associated with any of our mineral interests are not likely to be recovered, we would incur a write-down of our investment in these interests. All of these factors may result in losses in relation to amounts spent that are not recoverable, or that result in additional expenses. We have no history of producing commercial products from our current mining properties and there can be no assurance that we will successfully establish mining operations or profitably produce minerals. We have no history of producing commercial products from our current mining properties. We do not produce commercial products and do not currently generate operating earnings. While we seek to move our Elk Creek Project from a development stage property to a production stage property, such efforts will be subject to all of the risks associated with establishing new mining operations and business enterprises, including: • the timing and cost, which are considerable, of the construction of mining and processing facilities; • the availability and costs of skilled labor and equipment; • compliance with environmental and other governmental approval and permit requirements; • the availability of funds to finance construction and development activities; • potential opposition from non-governmental organizations, local groups, or local residents that may delay or prevent development activities; and • potential increases in construction and operating costs due to changes in the cost and availability of labor, fuel, power, materials, and equipment and supplies, and the time elapsed since the most recent estimates of cost and availability were made. It is common in new mining and processing operations to experience unexpected problems and delays during engineering, procurement, construction, commissioning, and initial operations. In addition, our management and workforce will need to be expanded, and sufficient housing and other support systems for our workforce will have to be established. This could result in delays in the commencement of production and increased costs of production. Accordingly, we cannot assure you that our activities will result in profitable operations or that we will successfully establish mining and processing operations. Results of metallurgical testing by us may not be favorable to, or as expected by, us. We have completed significant bench, mini-pilot, and pilot scale metallurgical testing on material from the Elk Creek Project and will continue to complete necessary metallurgical testing at the bench, mini-pilot, and pilot scale as the exploration and, if warranted, development of the Elk Creek Project progresses. There can be no assurance that the results of such metallurgical testing will be favorable to, or will be as expected by, us. Furthermore, there can be no certainty that metallurgical recoveries obtained in bench or pilot scale tests will be achieved in either subsequent testing or commercial operations. The development of a complete metallurgical process to produce saleable final products from the Elk Creek Project is a complex and resource-intensive undertaking that may result in overall schedule delays and increased project costs for us. The success of our business will depend, in part, on the growth of existing and emerging uses for scandium and rare earth products. We intend to produce scandium and rare earth products at the Elk Creek Project that are used in critical industries, including AI data centers, electronics, aerospace and defense systems, robotics, and other advanced technologies. The success of our business depends, in part, on the continued growth of these end-markets and the successful commercialization of scandium and rare earth products. If the market for these existing and emerging technologies does not grow as we expect, grows slower than we expect, or if the demand for our products in these markets decreases, then our business, prospects, financial condition and operating results could be harmed. Although periods of high market prices would generally be beneficial to our financial performance, any such period could also create economic pressure to identify or create alternate technologies that ultimately could depress the long-term demand for our products. Any unexpected costs or delays in the production of scandium or rare earth products, or less than expected demand for the existing and emerging technologies that use scandium or rare earth products, could have a material adverse effect on the results of our operations.
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18 Our recovery process for our planned products has been evaluated at a demonstration scale but has not been fully validated on a commercial scale. The 2026 S-K 1300 Elk Creek Technical Report Summary describes the process by which we expect to recover scandium, niobium, titanium and the rare earth products from the Elk Creek Project’s ore body. Although demonstration-scale testing has achieved the targeted recovery rates, the full recovery and separation process has not been operated on a commercial scale or with actual production-stream materials at commercial throughput, and commercial samples of separated products have not yet been produced through the complete process. There can be no assurance that the recovery process will perform as designed on a commercial scale, produce products meeting required purity and quality specifications, or achieve the recoveries assumed in the 2026 S-K 1300 Elk Creek Technical Report Summary. Failure to validate the recovery process on a commercial scale could reduce the Elk Creek Project’s revenue, adversely affect the commercial viability of the Elk Creek Project, and have a material adverse effect on our business, results of operations, and financial condition. Estimates of resources and reserves are subject to evaluation uncertainties that could result in project failure. Our exploration and future mining operations, if any, are and would be faced with risks associated with being able to accurately predict the quantity and quality of resources/reserves within the earth using statistical sampling techniques. Estimates of any resources/reserves on any of our properties would be made using samples obtained from appropriately placed trenches, test pits, underground workings, and intelligently designed drilling. There is an inherent variability of assays between check and duplicate samples taken adjacent to each other and between sampling points that cannot be reasonably eliminated. Additionally, there also may be unknown geologic details that have not been identified or correctly appreciated at the current level of accumulated knowledge about our properties. This could result in uncertainties that cannot be reasonably eliminated from the process of estimating resources/reserves. If these estimates were to prove to be unreliable, we could implement an exploitation plan that may not lead to commercially viable operations in the future. Any material changes in mineral resource/reserve estimates and grades of mineralization will affect the economic viability of placing a property into production and a property’s return on capital. Mineral resource/reserve estimates may require adjustments or downward revisions. In addition, the grade of ore ultimately mined, if any, may differ from that indicated in the 2026 S-K 1300 Elk Creek Technical Report Summary. Minerals recovered in small scale tests may not be duplicated in large scale tests under on-site conditions or at commercial production scale. The mineral resource and mineral reserve estimates included in the 2026 S-K 1300 Elk Creek Technical Report Summary and contained in this Annual Report on Form 10-K have been determined based on assumed future prices, cut-off grades, and operating costs that may prove to be inaccurate. Extended declines in market prices for our products may render portions of our resource/reserve estimates uneconomic and may result in reduced reported resources/reserves or may adversely affect any commercial viability determinations we may reach. Any material reductions in estimates of resources/reserves could have a material adverse effect on our Common Share price and on the value of our properties. We face intense competition in the mining industry. The mining industry is intensely competitive in all of its phases, and we compete with other companies for capital. In particular, the U.S. Government has made, and may continue to make, significant investments in other companies engaged in the mining of scandium, REEs, and other critical minerals, which may provide those companies with greater access to capital, resources, and operational support. As a result of this competition, some of which is with large established mining companies with substantial capabilities and with greater financial and technical resources than ours, we may be unable to obtain financing for the Elk Creek Project on terms we consider acceptable, or at all, or to acquire and develop additional properties in the future. Government investment in competing projects may also accelerate the development of alternative sources of supply for our products, which could reduce the prices we are able to realize for our products, and diminish our ability to negotiate offtake or supply agreements on favorable terms. In addition, we compete with others in efforts to obtain resources to advance the Elk Creek Project to construction and commercial operation, including mining and processing equipment, as well as qualified managerial and technical employees. If we are unable to successfully compete for required resources, including qualified employees, we may have difficulty in advancing the Elk Creek Project to construction and commercial operation. In addition, in competing for qualified personnel, we may be required to pay compensation or benefits relatively higher than those paid in the past, and the availability of qualified personnel may be limited in high-demand periods. Changes in geopolitical conditions and U.S. critical minerals policy could reduce the strategic importance of our planned products and adversely affect our business. A part of our business strategy is supported by the current geopolitical and national security environment, including ongoing trade tensions between the United States and China, China’s restrictions on exports of certain strategic minerals, and U.S. Government initiatives to strengthen domestic supply chains for critical minerals. These developments have increased interest in and public support for U.S.-based critical mineral projects like the Elk Creek Project.
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19 There is no assurance that these conditions will persist or that the Elk Creek Project will benefit from this strategic focus. Certain government agencies may possess the means to finance only a limited number of critical minerals projects, which could result in fewer projects being funded and increased competition for such support. Our ability to obtain funds or incentives from U.S. Government sources is subject to the availability of funds under applicable government programs and there is no guarantee that there will be opportunities for us to receive such financing or support or that we will be successful in obtaining any grants, awards, loans, or other incentives. Any improvement in U.S.-China relations, reduction or removal of tariffs or export controls, a shift in U.S. Government priorities regarding access to critical minerals, or identification of other readily available sources of our planned products, could decrease or eliminate the perceived strategic value of domestic production of certain strategic minerals, including scandium, dysprosium and terbium. Similarly, if China were to resume or expand exports of certain strategic minerals, including scandium, dysprosium and terbium, global supply and pricing dynamics could change materially, which could reduce the focus on developing U.S.-based projects. In addition, U.S. Government agencies, including the DoW, may decide not to continue, or may significantly reduce efforts, to promote domestic critical minerals development. If U.S. Government interest or policy support for domestic critical mineral projects declines, our ability to secure project financing and establish the commercial viability of the Elk Creek Project could be adversely affected. Any such decline could have a material adverse effect on our business, results of operations, and financial condition. Difficulties in water balance management at our Elk Creek Project could negatively affect our potential production and economics at the project. The Company has conducted three field investigations and two major technical studies into the hydrogeology of the Elk Creek carbonatite, which is the geologic formation which hosts the mineralized material that would be extracted by the Company’s mining operations. The Company expects to encounter significant amounts of water in the carbonatite, which will need to be pumped out of the formation to facilitate a mining operation. Water quality analyses have demonstrated that this water will have elevated temperature and salt content when compared to other water resources in the area. While the Company has developed plans to treat water produced from the mine for use in its operations, there is no guarantee that the permits needed for the treatment of the water or the disposal of the resultant waste products will be issued by the State of Nebraska, nor is there any guarantee that such permits will be issued in a timely fashion. Further, based on such plans, the operations will rely on a water treatment system to achieve zero discharge of wastewater, and there is no guarantee that this system will function as designed or achieve nameplate treatment capacity. Title to our properties may be subject to other claims that could affect our property rights and claims. There are risks that title to our properties may be challenged or impugned. Our Elk Creek Project is located in Nebraska and may be subject to prior unrecorded agreements or transfers or native land claims, and title may be affected by undetected defects. The property we already own will allow us to construct the Elk Creek Project once sufficient project financing is obtained. Our current land and/or mineral rights lease agreements between ECRC and individual landowners give us an OTP, which may be used to support potential future operations, additional mineral exploration activities, and expansion. The rights of the current owners to sell the property subject to these options may be subject to prior unrecorded or unknown claims to title. Further, our current OTP agreements are of fixed duration and expire between December 2029 and May 2040, and we may incur additional cost and delays in securing renewals of such OTPs. We have investigated our rights to explore and exploit the Elk Creek Project resource/reserve and, to the best of our knowledge, our rights in relation to lands covering the Elk Creek Project resource/reserve are in good standing. However, there may be valid challenges to the title of our properties that, if successful, could impair development and/or operations. Our properties and operations may be subject to litigation or other claims. From time to time our properties or operations may be subject to disputes that may result in litigation or other legal claims. We may be required to assert or defend against these claims, which will divert resources and management time from operations. The costs of these claims or adverse filings may have a material effect on our business and results of operations. We do not currently insure against all the risks and hazards of mineral exploration, development, and mining operations. Exploration, development, mining, and surface operations involve various hazards, including environmental hazards, industrial accidents, metallurgical and other processing problems, unusual or unexpected rock formations, structural cave-ins or slides, flooding, fires, and periodic interruptions due to inclement or hazardous weather conditions. These risks could result in damage to or destruction of mineral properties, facilities, or other property, personal injury, environmental damage, delays in operations, increased cost of operations, monetary losses, and possible legal liability. We may not be able to obtain insurance to cover these risks at economically feasible premiums or at all. We may elect not to insure where premium costs are
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20 disproportionate to our perception of the relevant risks. The payment of such insurance premiums and of such liabilities would reduce the funds available for exploration and production activities. Risks Related to Government Regulation We may not be able to obtain or renew all required permits and licenses to place any of our properties into production. Our current and future operations, including development activities and commencement of production, if warranted, on the Elk Creek Project, require permits from governmental authorities and such operations are and will be governed by laws and regulations governing prospecting, development, mining, production, exports, taxes, labor standards, occupational health, waste disposal, toxic substances, land use, environmental protection, mine safety, and other matters. Companies engaged in mineral property exploration and the development or operation of mines and related facilities generally experience increased costs, as well as delays in production and other schedules as a result of the need to comply with applicable laws, regulations, and permits. We cannot predict if all permits that we may require for continued exploration, development, or construction of mining facilities and conduct of mining operations will be obtainable or renewable on reasonable terms, if at all. Costs related to applying for and obtaining permits and licenses may be prohibitive and could delay our planned exploration and development activities. Failure to comply with applicable laws, regulations, and permitting requirements may result in enforcement actions, including orders issued by regulatory or judicial authorities causing operations to cease or be curtailed, and may include corrective measures requiring capital expenditures, installation of additional equipment, or remedial actions. Facilities associated with the Elk Creek Project, such as the mine, surface plant, tailings facilities, stockpiles and supporting infrastructure, are likely to either temporarily or permanently impact water bodies and wetlands that are subject to regulation by the USACE as Waters of the United States (“WOUS”). We believe that we have obtained the necessary USACE permits to construct the project, but changes to the design or layout of the facility may trigger the USACE to require us to obtain and maintain additional permits for the Elk Creek Project. The duration of this permitting exercise is dictated by the USACE and would need to be completed before facilities that would impact WOUS could be constructed. We may experience delays or additional costs in relation to obtaining the necessary permits and these delays and additional costs could negatively affect the economics of the Elk Creek Project and our results of operations. Parties engaged in mining operations may be required to compensate those suffering loss or damage by reason of the mining activities and may have civil or criminal fines or penalties imposed for violations of applicable laws or regulations. Amendments to current laws, regulations, and permits governing operations and activities of mining companies, or more stringent implementation thereof, could have a material adverse impact on our operations and cause increases in capital expenditures or production costs or reduction in levels of production at producing properties or require abandonment or delays in development of new mining properties. We are subject to significant governmental regulations that affect our operations and costs of conducting our business. Our current and future operations, including development of the Elk Creek Project, are and will be governed by laws and regulations, including: • laws and regulations governing mineral concession acquisition, prospecting, development, mining, and production; • laws and regulations related to exports, taxes, and fees; • labor standards and regulations related to occupational health and mine safety; and • environmental standards and regulations related to waste disposal, toxic substances, land use reclamation, and environmental protection. Companies engaged in development activities often experience increased costs and delays in production and other schedules as a result of the need to comply with applicable laws, regulations, and permits. Failure to comply with applicable laws, regulations, and permits may result in enforcement actions, including the forfeiture of mineral claims or other mineral tenures and/or orders issued by regulatory or judicial authorities requiring operations to cease or be curtailed, and may include corrective measures requiring capital expenditures, installation of additional equipment, or costly remedial actions. We may be required to compensate those suffering loss or damage by reason of our development activities and may have civil or criminal fines or penalties imposed for violations of such laws, regulations, and permits. Existing and possible future laws, regulations, and permits governing operations and activities of mineral development companies, or more stringent implementation, could have a material adverse impact on our business and cause increases in capital expenditures or require abandonment or delays in development. Our Elk Creek Project is located in Nebraska, and while the State does have a comprehensive and modern set of environmental regulations, it does not have specific regulations with respect to permitting or reclaiming mines which could potentially impact the total time to market for the project.
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21 Our activities are subject to environmental laws and regulations that may change, thereby increasing our costs of doing business and restricting our operations. All phases of our operations are subject to environmental regulation in the jurisdictions in which we operate. Environmental legislation is evolving in a manner that may require stricter standards and enforcement, increased fines and penalties for non-compliance, more stringent environmental assessments of proposed projects, and a heightened degree of responsibility for companies and their officers, directors, and employees. These laws address emissions into the air, discharges into water, management of waste, management of hazardous substances, protection of natural resources, antiquities and endangered species, and reclamation of lands disturbed by mining operations. Compliance with environmental laws and regulations, and future changes in these laws and regulations, may require significant capital outlays and may cause material changes or delays in our operations and future activities. It is possible that future changes in these laws or regulations could have a significant adverse impact on our properties or some portion of our business, causing us to re-evaluate those activities at that time. Regulations and pending legislation governing issues involving climate change could result in increased operating costs, which could have a material adverse effect on our business. A number of governments or governmental bodies have introduced or are contemplating legislative and/or regulatory changes in response to concerns about the potential impact of climate change. Legislation and increased regulation regarding climate change could impose significant costs on us, on our future venture partners, if any, and on our suppliers, including costs related to increased energy requirements, capital equipment, environmental monitoring and reporting, and other costs necessary to comply with such regulations. Any adopted future climate change regulations could also negatively impact our ability to compete with companies situated in areas not subject to such limitations. Given the emotion, political significance, and uncertainty surrounding the impact of climate change and how it should be dealt with, we cannot predict how legislation and regulation will affect our financial condition, operating performance, and ability to compete. Furthermore, even without such regulation, increased awareness and any adverse publicity in the global marketplace about potential impacts on climate change by us or other companies in our industry could harm our reputation. The potential physical impacts of climate change on our operations are highly uncertain and could be particular to the geographic circumstances in areas in which we operate and may include changes in rainfall and storm patterns and intensities, water shortages, changing sea levels, and changing temperatures. These impacts may adversely impact the cost, production, and financial performance of our operations. Our failure to comply with applicable anti-corruption, anti-bribery, anti-money laundering and similar laws and regulations could negatively impact our reputation and results of operations. Our governance and compliance policies and processes may not prevent potential breaches of law or accounting or other governance practices. Our operating and ethical codes, among other standards and guidance, may not prevent instances of fraudulent behavior and dishonesty, nor guarantee compliance with legal and regulatory requirements. We may be required to comply with anti-corruption laws and regulations imposed by governments with jurisdiction over our operations, which may include U.S. and Canadian anti-bribery and corruption legislation, as well as the laws of other countries where we do business or have a close connection. These laws and regulations may restrict our operations, trade practices, investment decisions, and partnering activities. We are subject to the jurisdiction of various governments and regulatory agencies around the world, which may bring our personnel and representatives into contact with “foreign officials” responsible for issuing or renewing permits, licenses or approvals or for enforcing other governmental regulations. Our failure to successfully comply with these laws and regulations may expose us to reputational harm, as well as significant sanctions, including criminal fines, imprisonment, civil penalties, disgorgement of profits, injunctions, and debarment from government contracts, as well as other remedial measures. Investigations of alleged violations can be expensive and disruptive. Compliance, on the other hand, often adds cost and complexity to the permitting process and subsequent operations. There can be no guarantee that we will effectively prevent violations by our employees or business partners acting on our behalf, for which we may be held responsible, and any such violation could adversely affect our reputation, business, results of operations and financial condition. Land reclamation requirements for our properties may be burdensome and expensive. Although variable depending on location and the governing authority, land reclamation requirements are generally imposed on mineral exploration companies (as well as companies with mining operations) in order to minimize long-term effects of land disturbance. Reclamation may include requirements to: • control dispersion of potentially deleterious effluents; • treat ground and surface water to achieve water quality standards; and
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22 • reasonably re-establish pre-disturbance landforms and vegetation. In order to carry out reclamation obligations imposed on us in connection with our potential development activities, we must allocate financial resources that might otherwise be spent on further exploration and development programs. We plan to set up a provision for our reclamation obligations on our properties, as appropriate, but this provision may not be adequate. If we are required to carry out unanticipated reclamation work, our financial position could be adversely affected. Risks Related to Our Debt We expect to incur substantial debt in connection with the Elk Creek Project, which will require a significant amount of cash to service, require us to comply with certain covenants and restrictions, and could impair our ability to obtain additional financing. We expect to incur substantial debt as part of our plan to obtain project financing sufficient to cover initial capital costs and other related expenses necessary to the commencement and completion of construction of the Elk Creek Project, which may include, but is not limited to, the EXIM Financing. We currently anticipate that the upfront capital expenditure amount for the Elk Creek Project will be funded through a combination of debt and equity financing, with approximately 65% of such amount being funded from the net proceeds of debt financing. We will require a significant amount of cash to service any future debt obligations and our ability to generate cash will depend on our future operations, which are subject to prevailing industry conditions and other factors, many of which are beyond our control. We also expect that any agreements governing our future indebtedness will require us to comply with certain covenants and restrictions that limit our ability to engage in activities that may be in our long-term best interests. Any failure to comply with such covenants and restrictions could adversely affect our reputation, business, results of operations and financial condition. In addition, our articles of incorporation do not limit the amount of indebtedness that we may incur. Any substantial indebtedness could impair our ability to obtain additional financing on a timely basis, or at all, for working capital or to take advantage of business opportunities that may arise. Risks Related to the Common Shares NioCorp may be a “passive foreign investment company” for the current taxable year and for one or more future taxable years, which may result in materially adverse U.S. federal income tax consequences for U.S. investors. If NioCorp is a passive foreign investment company (“PFIC”) for any taxable year, or portion thereof, that is included in the holding period of a U.S. holder of Common Shares or other securities of NioCorp, such U.S. holder may be subject to certain adverse U.S. federal income tax consequences. These adverse tax consequences include requirements to treat any gain realized upon a disposition of Common Shares or other securities, or any “excess distribution” received on Common Shares, as ordinary income, to pay an interest charge on a portion of such gain or distribution, and certain additional reporting requirements. Such consequences may be mitigated with respect to Common Shares (but not with respect to Warrants or other securities of NioCorp) if the holder thereof makes a timely and effective “qualified electing fund” or “QEF” election or a “mark-to-market” election. A U.S. holder of Common Shares that makes a QEF election generally must include in income on a current basis for U.S. federal income tax purposes its share of NioCorp’s net capital gain and ordinary earnings for any taxable year in which it is a PFIC, whether or not NioCorp distributes any amount to its shareholders. A U.S. holder of Common Shares that makes a mark-to-market election generally must include as ordinary income each year the excess of the fair market value of the Common Shares over the taxpayer’s basis therein. NioCorp generally will be classified as a PFIC for a taxable year if (a) 75% or more of its gross income for such year is “passive income” (generally, dividends, interest, rents, royalties, and gains from the disposition of assets producing passive income) or (b) at least 50% or more of the value of its assets produce, or are held for the production of, passive income, based on the quarterly average of the fair market value of such assets. NioCorp believes that it was classified as a PFIC for its taxable years ended June 30, 2026 and 2025 and, based on the current composition of its income and assets, as well as current business plans and financial expectations, may be classified as a PFIC for its current or future taxable years. Any conclusion regarding PFIC status is a factual determination that must be made annually at the close of each taxable year and, thus, is subject to change. In addition, even if NioCorp concluded it did not qualify as a PFIC, it is possible that the U.S. Internal Revenue Service (the “IRS”) could assert, and that a court could sustain, a determination that NioCorp is a PFIC. Accordingly, there can be no assurance that NioCorp will not be treated as a PFIC for any taxable year. The PFIC rules are complex and each holder of Common Shares or other securities of NioCorp should consult its own tax advisors regarding these rules and the U.S. federal income tax consequences of the acquisition, ownership, and disposition of such securities. The 2023 business combination with GXII could result in NioCorp becoming subject to materially adverse U.S. federal income tax consequences.
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23 Section 7874 and related sections of the U.S. Internal Revenue Code of 1986, as amended (the “Code”), provide for certain adverse tax consequences when the stock of a U.S. corporation is acquired by a non-U.S. corporation in certain transactions in which former shareholders of the U.S. corporation come to own 60% or more of the stock of the non-U.S. corporation (by vote or value, and applying certain specific counting and ownership rules). These adverse tax consequences include (i) potential additional required gain recognition by the U.S. corporation, (ii) treatment of certain payments to the non-U.S. corporation that reduce gross income as “base erosion payments,” (iii) an excise tax on certain options and stock-based compensation of the U.S. corporation, (iv) disallowance of “qualified dividend” treatment for distributions by the non-U.S. corporation, and (v) if former shareholders of the U.S. corporation come to own 80% or more of the stock of the non-U.S. corporation, treatment of the non-U.S. corporation as a U.S. corporation subject to U.S. federal income tax on its worldwide income (in addition to any tax imposed by non-U.S. jurisdictions). If the 2023 business combination with GXII results in the application of any of these, or any other, adverse tax consequences, NioCorp could incur significant additional tax costs. While NioCorp currently does not believe the 2023 business combination with GXII will cause such adverse tax consequences as a result of Section 7874 and related sections of the Code, this determination is subject to significant legal and factual uncertainty. NioCorp has not sought and will not seek any rulings from the IRS as to the tax treatment of the 2023 business combination with GXII or any related transactions. Further, there can be no assurance that your tax advisor, the IRS, or a court, will agree with the position that NioCorp is not subject to these adverse tax consequences. Our Common Share price may be volatile and as a result you could lose all or part of your investment. In addition to volatility associated with equity securities in general, the value of your investment could decline due to the impact of any of the following factors upon the market price of the Common Shares: • material changes to mineral resource/reserve estimates, grades of mineralization or economic viability of the Elk Creek Project; • our ability to obtain sufficient financing for the Elk Creek Project; • decline in demand for Common Shares; • downward revisions in securities analysts’ estimates or changes in general market conditions; • technological innovations by competitors or in competing technologies; • investor perception of our industry or our prospects; • the impact of trade policies and tariffs, or changes and uncertainties related thereto; and • general economic trends. In particular, any material reductions in resource/reserve estimates, material increases in capital or operating costs relative to those reflected in the 2026 S-K 1300 Elk Creek Technical Report Summary, or other adverse changes to project economics could have a material adverse effect on the value of our properties and the market price of our Common Shares. See “We face numerous uncertainties in estimating our mineral reserves and resources and inaccuracies in our estimates could result in lower than expected revenues, higher than expected costs, and decreased profitability” in Item 1A., Risk Factors above. From July 1, 2025, to the date of this report, the trading price of our stock on the Nasdaq has ranged from a low of $2.19 to a high of $11.67. In addition, stock markets in general have experienced extreme price and volume fluctuations, and the market prices of securities have been highly volatile. These fluctuations are often unrelated to operating performance and may adversely affect the market price of the Common Shares. As a result, you may be unable to sell any Common Shares you acquire at a desired price. We have never paid dividends on the Common Shares. We have not paid dividends on the Common Shares to date, and we may not be in a position to pay dividends for the foreseeable future. Our ability to pay dividends with respect to the Common Shares will depend on our ability to successfully develop one or more properties and generate earnings from operations. Further, our initial earnings, if any, will likely be retained to finance our operations. Any future dividends on Common Shares will depend upon our earnings, our then-existing financial requirements, and other factors, and will be at the discretion of our Board.
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24 Future sales, or the perception of future sales, of Common Shares by existing shareholders or by us, or future dilutive issuances of Common Shares by us, or future exercises or exchanges of outstanding Warrants or securities exchangeable for Common Shares, could adversely affect prevailing market prices for the Common Shares and cause investors to suffer dilution in their net book value per Common Share. In addition to potential debt financing, our plan to obtain project financing sufficient to cover initial capital costs and other related expenses necessary to the commencement and completion of construction of the Elk Creek Project includes the sale and issuance of equity securities which may include, but is not limited to, Common Shares, Warrants, or pre-funded Warrants. Sales of a substantial number of Common Shares in the public market could occur at any time, including issuances and sales of additional Common Shares by us and sales by other security holders. These sales, or the market perception that the holders of a large number of Common Shares or securities convertible, exercisable, or exchangeable into Common Shares intend to sell Common Shares, could reduce the prevailing market price of the Common Shares. The effect, if any, that future public sales of these securities or the availability of these securities for sale will have on the market price of the Common Shares is uncertain. If the market price of the Common Shares were to drop as a result, this might impede our ability to raise additional capital and might cause remaining shareholders to lose all or part of their investment. The Articles of NioCorp, as amended, permit us to issue an unlimited number of Common Shares. Subject to the requirements of the British Columbia Business Corporations Act and Nasdaq, we will not be required to obtain the approval of the NioCorp shareholders for the issuance of additional Common Shares. We have issued Common Shares in the past and intend to continue to issue Common Shares to finance our activities in the future. In addition, outstanding Options and Warrants and securities convertible into or exchangeable for Common Shares may be exercised, converted, or exchanged resulting in the issuance of additional Common Shares. If we issue additional Common Shares or decide to enter into joint ventures with other parties in order to raise financing through the sale of equity securities, investors’ interests in the Company will be diluted and investors may suffer dilution in their net book value per Common Share depending on the price at which such securities are sold. We are subject to the continued listing criteria of the Nasdaq and our failure to satisfy these criteria may result in delisting of the Common Shares. Our Common Shares are currently listed on the Nasdaq under the symbol “NB”. The public NioCorp Assumed Warrants are currently listed on Nasdaq under the symbol “NIOBW.” The Nasdaq has rules for continued listing. In order to maintain the listings, we must maintain certain financial and share distribution targets, including maintaining a minimum number of public shareholders. If Nasdaq delists the Common Shares, investors may face material adverse consequences, including, but not limited to, a lack of a trading market for the Common Shares, reduced liquidity, a determination that our Common Shares are a “penny stock,” decreased analyst coverage of the Company, and an inability for us to obtain additional financing to fund our operations. Our Rights Plan includes terms and conditions that could discourage a take-over or other transaction that shareholders may consider favorable. On November 21, 2025, the Company adopted the Rights Plan pursuant to the Original Rights Plan Agreement, between the Company and the Rights Agent. One Right was issued for each Common Share outstanding as of December 4, 2025, and a Right automatically attaches to each Common Share subsequently issued until the expiration of the Rights Plan. The Rights generally become exercisable only if a person or group acquires, or announces the current intention of commencing a take-over bid to acquire, beneficial ownership of 20% or more of the Company's outstanding Common Shares, other than through a permitted bid made in compliance with applicable Canadian take-over bid rules. If the Rights become exercisable, each holder of a Right, other than the acquiring person, would be entitled to purchase additional Common Shares at a discount to the then-current market price. On April 6, 2026, following approval by the Company's shareholders at the Company's annual general meeting held on April 6, 2026, the Company and the Rights Agent entered into the Amended Rights Plan Agreement, which amended and restated the Original Rights Plan Agreement in its entirety. Under the Original Rights Plan Agreement, the Rights Plan would have expired on May 21, 2026. Under the Amended Rights Plan Agreement, the Rights Plan now expires at 5:00 p.m. (Toronto time) on the date of the Company's next annual general meeting. The Board adopted the Rights Plan to help ensure that all shareholders of the Company are treated equally and fairly in the event of any unsolicited take-over bid or other attempt to acquire control of the Company (including by way of a “creeping take-over bid”). The Rights Plan was not adopted in response to any specific take-over bid or other proposal to acquire control of the Company.
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25 The Rights Plan will cause substantial dilution to any person, entity or group that acquires beneficial ownership of 20% or more of the outstanding Common Shares. As a result, the overall effect of the Rights Plan and the issuance of the Rights may be to discourage any person, entity or group from gaining a control or control-like position in the Company or engaging in other tactics, potentially disadvantaging the interests of the Company’s shareholders, without negotiating with the Board and without paying an appropriate control premium to all shareholders. The Rights Plan is intended to, among other things, (i) encourage potential bidders to treat the Company’s shareholders fairly and equally and preserve control premiums and value for shareholders and (ii) provide the Board and shareholders adequate time to appropriately respond on an informed basis. Nevertheless, the Rights Plan may be considered to have certain anti-take- over effects, including potentially discouraging a third party from attempting to obtain a substantial position in the Common Shares or seeking to obtain control of the Company and discouraging a take-over attempt that shareholders may consider favorable or that could result in a premium over the market price of the Common Shares. Even in the absence of a take-over attempt, the Rights Plan may adversely affect the prevailing market price of Common Shares if it is viewed as discouraging take-over attempts in the future. ITEM 1B. UNRESOLVED STAFF COMMENTS None. ITEM 1C. CYBERSECURITY Cybersecurity risk management is integrated into the Company’s enterprise-wide risk management. Our Board has overall oversight responsibility for our risk management and management is responsible for identifying, considering, and assessing material risks to the Company. Our Chief Financial Officer is responsible for assessing and managing cybersecurity risks; however, as a smaller reporting company, we currently do not have a dedicated cybersecurity team. Our Chief Financial Officer reports to the Board regarding financial and operating risks, including cybersecurity risks. Our Chief Financial Officer has experience in managing public companies and assessing financial and operating risks. Our cybersecurity risk management is designed to provide a framework for assessing, identifying, and managing material risks from cybersecurity threats and to respond to cybersecurity incidents, including material risks associated with the use of services provided by third-party service providers. We rely on the cybersecurity protections of many of our third-party service providers. Our primary third- party service providers utilize two-factor authentication as well as login and password protections with email verifications. We are in the process of evaluating our cybersecurity needs and developing appropriate measures to enhance our cybersecurity posture. Our goal is to establish a cybersecurity framework that is commensurate with our size, complexity, and nature of our operations. We have experienced cybersecurity threats and cybersecurity incidents in the past, and may experience cybersecurity threats and cybersecurity incidents in the future. For the year ended June 30, 2026, the Company had no material cybersecurity incidents or threats that have materially affected or were reasonably likely to materially affect our business strategy, results of operations or financial condition. Despite our efforts, we cannot eliminate all risks from cybersecurity threats or provide assurances that we have not experienced an undetected cybersecurity incident. ITEM 2. PROPERTIES Elk Creek Project, Nebraska Our principal mineral property is the Elk Creek Property, a development stage property that is expected to produce eight commercial mineral products: ferroniobium, scandium oxide, titanium tetrachloride, neodymium-praseodymium (“NdPr”) oxide, dysprosium oxide, terbium (“Tb”) oxide, SEG carbonate, and heavy rare earth ("heavies") carbonate. As discussed in greater detail below, the Elk Creek Project has established measured, indicated, and inferred resources along with proven and probable reserves. The below information is in part summarized or extracted from our 2026 S-K 1300 Elk Creek Technical Report Summary, which is filed as Exhibit 96.1 to this Annual Report on Form 10-K. The 2026 S-K 1300 Elk Creek Technical Report Summary has an overall effective date of June 30, 2026. The Company does not have any other material properties. The qualified persons responsible for the 2026 S-K 1300 Elk Creek Technical Report Summary are: • Dahrouge Geological Consulting USA Ltd.; • SMH Process Innovation;
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26 • Dumas Contracting USA Inc.; • Amplify Mine Planning LLC; • BBA Consultants International LP (formerly Tierra Group International, Ltd.); • Olsson; • Adrian Brown Consultants Inc.; • Andrieux & Associates Geomechanics Consulting, L.P.; • Tetra Tech; • Metallurgy Concept Solutions; • Magemi Mining Inc.; • T Engineering; and • Scott Honan, M.Sc., SME-RM, NioCorp. A table of the sections for which each qualified person is responsible is included in Section 2.6 of the 2026 S-K 1300 Elk Creek Technical Report Summary. Except for Scott Honan, none of the qualified persons is affiliated with the Company. Mr. Honan is the Chief Operating Officer of the Company. The disclosure of scientific or technical information in this Annual Report on Form 10-K was reviewed and approved by Mr. Honan who is a qualified person as defined in NI 43-101, and Mr. Honan has verified the data disclosed herein. The 2026 S-K 1300 Elk Creek Technical Report Summary summarizes the 2026 Elk Creek Study, which, among other matters, updates the Elk Creek Project’s economics to incorporate the expanded product offering, including REEs, revises mine and processing design, and updates mineral resource and mineral reserve estimates and current capital and operating cost estimates. The 2026 Elk Creek Study comprises the results of the technical and economic analyses conducted by the qualified persons, which were also presented in the 2026 NI 43-101 Elk Creek Technical Report. The 2026 Elk Creek Study qualifies as a feasibility study within the meaning given to such term under the CIM Definition Standards (2014) for purposes of NI 43-101 and qualifies as a pre-feasibility study within the meaning given to such term under S-K 1300. The reason that the 2026 Elk Creek Study does not qualify as a feasibility study under S-K 1300 is because additional work with respect to the engineering of and procurement for the planned surface plant is required to allow the qualified person to reduce the overall contingency range attributed to the initial capital expenditure estimate for the Elk Creek Project from the current 14% to less than or equal to 10%. Even as additional work is completed and the contingency range is reduced, accordingly, there can be no assurance that the actual initial capital expenditure requirements will not materially exceed estimates. Property Description and Location The Elk Creek Property consists of certain interests of NioCorp in land and mineral rights located in Johnson and Pawnee Counties, southeast Nebraska, USA. The carbonatite contains elements of economic significance, including niobium, titanium, and scandium, as well as several REEs. The Elk Creek Property is situated as shown below and is located within the USGS Tecumseh Quadrangle Nebraska SE (7.5 minute series) mapsheet in Sections 1-6, 9-11; Township 3N; Range 11E and Sections 19-23, 25-36; Township 4N, Range 11E, at approximately 40°16’ north and 96°11’ west in the State of Nebraska, in central USA. The Elk Creek Property is approximately 47 miles southeast of Lincoln, Nebraska, the state capital of Nebraska.
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27 Title and Ownership Land in the project area is exclusively owned by private entities, and there is no federal or state land in the project area. The Company has secured its rights to the project area by purchasing land from private landowners or by entering into agreements with the landowners as described below. Following the acquisition of an additional approximately 447 acres of land pursuant to existing OTPs during fiscal year 2026, the Company, through its subsidiary ECRC, owns the surface rights and/or mineral rights to approximately 710 acres of land in and around the project area. This includes an approximately one-square-mile (approximately 630-acre) section of which it owns the mineral rights to all but approximately 80 acres and all of the surface rights, all within the carbonatite footprint. The Elk Creek Project’s mine infrastructure and a portion of the supporting operations is planned to be located within this section. Ownership of the mineral rights in this section includes a 2% NSR royalty and grants us access to all of the Elk Creek Project’s mineral resources and mineral reserves. The land owned by ECRC currently houses the Company’s drill core inventory and geological sample repository in two steel core shed buildings, and the Company maintains vegetative cover on portions of the property that were formerly used for growing row crops. Additionally, the Company has begun construction of the main access, known as a “portal,” to the underground portion of the Elk Creek Project on the land owned by ECRC. The portal will serve as the primary access point for personnel, equipment, and materials, as well as to deliver ore from the underground mine to the surface production plant. As of June 30, 2026, the total book value of the Elk Creek Property and associated buildings and equipment was approximately $37.3 million. The Company also currently holds six OTPs that are associated with the Elk Creek Project and one perpetual easement on a land parcel adjacent to the Missouri River. The current optioned land package covers an area of approximately 1,011 acres and includes the land needed for the development of tailings storage facilities that are expected to be developed in phases over the Elk Creek Project’s proposed 40-year operating life. Details on the current OTPs held by the Company are shown in the table below. Active Lease Agreements (OTPs) Covering the Elk Creek Project as of September 2026 Agreement Identifier Acres Agreement Expiry Beethe007 163.75 January 20, 2031 Heidemann005 196.57 March 16, 2030 Nielsen001 249.82 June 25, 2030 Woltemath002 257.03 December 4, 2029 Krueger001 63.79 November 12, 2030 Shuey001 80.00 May 27, 2040
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28 The OTPs are between NioCorp’s subsidiary ECRC and the individual landowners. Land subject to the OTP agreements is currently used for agricultural purposes, including growing row crops (corn and soybeans) and pasturing livestock. The OTPs grant the Company an exclusive right to explore and evaluate the property during the term thereof, with an option to purchase the surface rights or a combination of the mineral and surface rights at any time during the term. The OTPs that involve mineral rights provide for a 2% NSR royalty. In general, exercise of an OTP is accomplished by paying the greater of a fixed amount per acre or a multiple of the appraised value at the time of purchase. If the land is not purchased by the Company during the term of the OTP and the land in question is needed for the Elk Creek Project, the Company intends to negotiate a new OTP with the landowner. Each OTP is accompanied by a negotiated payment to the landowner that is paid upon execution of the OTP by the Company and the landowner. As of June 30, 2026, the Company was obligated to make payments totaling approximately $48 over the next 9 years to maintain our rights under these OTPs. Land Tenure Map as of September 2026 Accessibility, Climate, Local Resources, Infrastructure and Physiography The Elk Creek Property is easily accessible year-round as it is situated approximately 47 miles southeast of Lincoln, Nebraska, the state capital, and approximately 68 miles south of Omaha, Nebraska. Access to the site can be completed via interstates and state highways or from one of the regional airports. There are several regularly scheduled flights to both Lincoln and Omaha, with Omaha providing more regular commercially serviced options. From Eppley Airfield in Omaha, Nebraska, the Elk Creek Property is accessed via paved roads on the main network. The section in which the Company plans to construct both the underground critical minerals mine and integrated surface processing facility associated with the Elk Creek Project, and where the mineral resource and mineral reserve are centered, is in Section 33, Township 4N, Range 11E within the USGS Tecumseh Quadrangle Nebraska SE (7.5 minute series) mapsheet. This section is immediately southwest of the junction of Nebraska state highways 50 and 62, which turns into county road 721 west of state highway 50. The Elk Creek Project will be accessed from the north from county road 721. A secondary access point is available on the east side of the project from state highway 50. Rail access is available in the town of Elk Creek, which is located 3 miles east of the project area. Southeast Nebraska is situated in a humid continental climate (Dfa) on the Köppen climate classification system. In eastern Nebraska, this climate is generally characterized by hot, humid summers and cold winters. Average winter temperatures vary between 13°F to 35°F. Average summer temperatures vary between 65°F to 88°F. Exploration and mining-related activities may be conducted all year round although severe winter weather and spring/early-summer thunderstorm activity can periodically affect operations.
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29 Average monthly precipitation (rain and liquid-equivalent snowfall) varies between 0.8 and 5.3 inches, with a mean annual total of approximately 32.3 inches. Average snowfall is approximately 22 inches. Nebraska is located within a region of the central United States that experiences severe thunderstorms and tornadoes, with peak tornado occurrence generally during May through July, although events can occur outside this period. The area is well developed with direct access to roads, rail, supply and distribution companies, and a local workforce, including heavy equipment operators. There are several local communities near the Elk Creek Property, including Elk Creek, Syracuse, Tecumseh and Pawnee City, that are capable of providing local housing for the Elk Creek Project construction and operating staff. There are several other communities within driving distance and the large cities of Lincoln and Omaha are also within reasonable driving distance. Both cities have substantial regional airports. The Elk Creek Project is expected to incorporate surface and underground infrastructure, as well as surface tailings and salt storage facilities. The offsite infrastructure is expected to include a water supply pipeline from the City of Tecumseh and temporary and permanent natural gas pipelines. On-site power is expected to be provided by a third-party microgrid using modular 2.5 megawatts ("MW") natural gas generators, rated at approximately 50 MW. Initially, a 15 MW construction microgrid is expected to be supplied, with gas from trucked liquefied natural gas and/or a temporary pipeline connection approximately 5 miles east. A permanent gas pipeline from a main distribution line approximately 30 miles west is expected to be connected around the end of the second construction year. Before the end of construction, the larger 50 MW microgrid is expected to replace the construction microgrid. Approximately 200 kilowatts ("kW") of grid power from the local power utility is also expected to be utilized via an existing connection. Water used for all on-site process needs and activities is expected to be supplied from mine dewatering activities, recycling, and from a local water utility. See “Planned Operations” below for additional information regarding proposed infrastructure related to the Elk Creek Project. The local topography of eastern Nebraska is relatively low-relief with shallow rolling hills intersected by shallow river valleys. Elevation varies from about 1,066 feet ("ft") to 1,276 ft above mean sea level. Bedrock outcrop exposure is nonexistent in the Elk Creek Project area. The majority of the area around the Elk Creek Project is used for cultivation of corn and soybeans, along with uses as grazing land. Native vegetation typical of eastern Nebraska is upland tall-grass, prairie and upland deciduous forests. Geology and Mineralization Geology The Elk Creek Property includes a carbonatite that has intruded older Precambrian granitic and low- to medium-grade metamorphic basement rocks. The carbonatite is an elliptical magmatic body with a northwest-trending long axis perpendicular to the strike of the Midcontinent Rift System, near the northern part of the Nemaha uplift. The carbonatite consists predominantly of dolomite, calcite and ankerite, with lesser chlorite, barite, phlogopite, pyrochlore, serpentine, fluorite, sulfides and quartz. It is, however, believed from stratigraphic reconstruction based on drill core observation in the area that the carbonatite is unconformably overlain by approximately 656 ft of essentially flat-lying Paleozoic marine sedimentary rocks, including carbonates, sandstones and shales of Pennsylvanian age. Mineralization The property hosts niobium, titanium, and scandium mineralization as well as REE mineralization that occurs within the Elk Creek carbonatite. The current extent of modeled mineralization is 3,937 ft (1,200 meters ("m")) along strike, 1,640 ft (500 m) wide, and 2,461 ft (750 m) in dip extent below the unconformity. Niobium, titanium, scandium, and rare earth elements are considered the main elements of interest. The deposit contains significant concentrations of niobium. Based on the metallurgical test work completed to date at several laboratories using QEMSCAN® analysis, the niobium mineralization is known to be fine grained, and that 77% of the niobium occurs in the mineral pyrochlore, while the balance occurs in an iron-titanium-niobium oxide mineral of varying composition. Within the Elk Creek carbonatite, a host of other elements exist with varying degrees of concentration. The Company has completed both whole rock analysis and multi-element analysis on all samples for the 2014 drilling program, described below, plus resampling of selected historical core/pulps between 2011 and 2021. Historical Exploration
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30 Drilling at the Elk Creek Property has been conducted in four phases. The first was during the 1970’s and 1980’s by the Molybdenum Company of America (“Molycorp”), the second in 2011 by Quantum Rare Earth Developments Corp (“Quantum” - NioCorp under its former name), the third in 2014 and 2015 by NioCorp and the fourth and latest program in 2025 by NioCorp. To date, 94 drill holes have been completed on the section in which NioCorp plans to construct both the underground critical minerals mine and integrated surface processing facility associated with the Elk Creek Project for a total of 196,114 ft (59,775 m), including 16 drill holes totaling 37,861 ft (11,540 m) completed in 2025. A further five holes totaling 11,001 ft (3,353.1 m) were drilled in 2015 for hydrogeological and geotechnical studies but were not used for resource estimation. All drilling has been completed using a combination of Tricone, Reverse Circulation (“RC”) or diamond drilling in the upper portion of the hole within the Pennsylvanian sediments. A portion of the 2014 drill holes used RC drilling within the Pennsylvanian sediments to increase drilling efficiency through cover material within areas of strong geological confidence. All drilling within the underlying carbonatite has been completed using diamond drilling methods. Summary of Drilling Database within Elk Creek Deposit Area Year Company Number of Holes in Carbonatite Complex Number of Holes on Project Project Hole Average Depth (m) Project Hole Average Depth (ft) Total Length (ft) Drillholes on Project Total Length (m) Drillholes on Project 1971-1986 Molycorp 114 49 530 1,738 85,171 25,960 2011 Quantum 5 4 739 2,423 9,692 2,954 2014-2015 NioCorp 24 24 805 2,641 63,390 19,321 2025 NioCorp 17 17 679 2,227 37,861 11,540 Total 160 94 688 2,257 196,114 59,775 Exploration History Private mineral leasing and exploration began in the early 1970s at the Elk Creek Property. Cominco American Inc. acquired mineral rights in 1973 and undertook exploration work, after which the rights were acquired by Molycorp in 1974. Molycorp completed detailed aeromagnetic surveying in 1973 and, in 1980, carried out a regional exploration program including gravity work, magnetic surveying, geologic mapping, surface sampling, and drilling. Between 1973 and 1986, Molycorp completed a regional drill program over an approximately 7 kilometers ("km") × 7 km gravity anomaly, totaling 114 drill holes for approximately 157,992 ft (48,156 m). Within the Elk Creek Deposit area, 27 holes totaling 52,848 ft (16,108 m) were drilled during the 1970–1980 period, forming the foundation of the historical drilling database. No known exploration was completed on the Elk Creek Property between 1986 and 2011. In 2010–2011, Quantum initiated verification and modernization of the historical dataset through Dahrouge Geological Consulting Ltd., compiling and checking historical drilling, lithology, and assay information, and completing resampling of historical material to assess comparability with historical results. Quantum then completed a 2011 diamond drilling program consisting of five inclined holes totaling 11,220 ft (3,420 m) of HQ core; three holes 7,605 ft (2,318 m) targeted the Elk Creek deposit and two holes tested regional REE targets. These holes were not used for mineral resource estimation. Following the acquisition of the Elk Creek Property, NioCorp advanced the Elk Creek Project through additional diamond drilling programs to improve confidence and support updated technical studies. Between 2014 and 2015 NioCorp drilled a total of 24 holes within the Elk Creek Deposit totaling approximately 63,390 ft (19,321 m). The program included data validation, metallurgical and mineralogical studies, geotechnical and hydrogeological studies all in support of resource estimation. During fiscal year 2022, NioCorp collected a total of 1,095 samples originating from 18 diamond drill holes completed by Molycorp, as discussed above. These samples were collected, and subsequently assayed, in order to fill in gaps in our records regarding REE grades and tonnage that may exist in the deposit. Assaying was conducted at Activation Laboratories (“ActLabs”) in Ancaster, Ontario. The assay results were subjected to a Quality Assurance and Quality Control (“QA/QC”) program consistent with industry best practices. During fiscal year 2026, NioCorp completed its previously announced drilling program at the Elk Creek Project (the “2025 Drilling Program”). The 2025 Drilling Program was specifically designed to target gaps within the mineral resource in support of converting a portion of the mineral resource from indicated and inferred to measured, indicated and inferred. During this campaign a total of 16 HQ diamond drillholes were completed totaling 37,861 ft (11,540 m). Assay results from the 2025 Drilling Program were added to the existing assay database and were used in the mineral resource estimate described below.
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31 Samples from the 2025 Drilling Program were prepared and analyzed by SGS North America in Lakefield, ON. Selected pulp duplicates were submitted to ActLabs for external check analysis, with a total of 490 external pulps analyzed to test for laboratory bias. Both laboratories’ procedures were consistent with previous drilling and sampling programs. Internal Controls NioCorp integrated a series of routine QA/QC procedures throughout the sampling and analysis portion of the drilling programs to ensure the highest level of quality was maintained throughout the process leading to the estimate of mineral reserves and mineral resources for the Elk Creek Project. This included the insertion of duplicate samples taken from various stages of the process, insertion of known control samples (standard reference materials, certified reference materials (“CRM”), and blanks) and sending third-party pulps to a secondary lab. To meet planned QA/QC insertion rates, the following guidelines were followed: • Field quartz blanks (1 in 20, or 5%) were inserted within or immediately after samples collected from mineralized intervals, targeting zones of elevated visual mineralization, where possible. • CRMs (1 in 20, or 5%) were inserted in the field with the sample sequence. • Field quarter-core duplicates (1 in 20, or 5%) were inserted to test mineralization and sampling variability. Additional details on the QA/QC program can be found in Section 8 of the 2026 S-K 1300 Elk Creek Technical Report Summary. Mineral deposits, including the Elk Creek deposit, are inherently uncertain because of variability at all scales and sparse sampling. In addition to uncertainty associated with estimation, there are specific risks and sources of uncertainty associated with the Elk Creek deposit. See Item 1A., Risk Factors. S-K 1300 and other similarly purposed International Codes (JORC, 2012; NI 43-101, 2014) are designed to require disclosure to the public of risks relating to mineral resource and reserve estimation as identified and evaluated by a qualified person. The qualified persons responsible for the 2026 S-K 1300 Elk Creek Technical Report Summary address the technical risks in various sections and identify the principal sources of uncertainty as geological confidence at depth and along the margins of the peripheral carbonatite domain, the size of the inferred mineral resource relative to the measured and indicated mineral resources, and the sensitivity of the NSR cut-off to metallurgical recovery and to commodity prices, particularly niobium and scandium. Additional descriptions of the risks and uncertainty associated with reported mineral reserves and resources can be found in Section 11 of the 2026 S-K 1300 Elk Creek Technical Report Summary. Economic Analysis Included in the 2026 S-K 1300 Elk Creek Technical Report Summary The metrics reported in the 2026 S-K 1300 Elk Creek Technical Report Summary are based on the cash flow model results. The metrics are on both a pre-tax and after-tax basis, on a 100% equity basis with no Elk Creek Project financing inputs and are in first quarter 2027 U.S. constant dollars. Key criteria used in the analysis are discussed in detail throughout this section. Principal Project Assumptions Description Value Pre-Production Period 35 months Process Plant Life 40 years Mine Operating Days per Year 365 Mill Operating Days per Year 365 Discount Rate, End of Period 8%
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32 Summary of Key Evaluation Metrics The following table sets forth mine and process plant production estimates for the Elk Creek Project over the 40-year operating life of the mine. Ore mined and ore processed refer to proven and probable mineral reserves. Description Value Ore Mined (short tons ("tons")) 45,929,462 Ore Mining Rate (tons/day) 3,047 Niobium Grade 0.76% Scandium Grade (parts per million, “ppm”) 69.3 TiO Grade 2.68% TREO Grade 0.34% Contained Nb (tons) 205,464 Contained Sc O (tons) 4,585 Contained TiCl (tons) 2,341,367 Contained TREO (tons) 53,309 Total Ore Processed (tons 000s) 45,929 Recovery, Nb 84.70% Recovery Sc 94.30% Recovery Ti 80.50% Recovery NdPr 93.04% Recovery Tb 94.40% Recovery Dy 94.60% Summary Pricing Assumptions The following table sets forth applicable benchmark product pricing assumptions used in the economic analysis. Except with respect to scandium trioxide, the economic analysis assumes constant prices with no inflationary adjustments. The realized pricing used in the economic analysis was based on a combination of third-party market studies, qualified person judgment, and management expertise to establish appropriate market pricing projections. The planned products of the Elk Creek Project, especially niobium and Sc2O3, are thinly traded without an established publicly available price discovery mechanism. Hence, detailed third-party market studies were completed for all four of the major product groups that are expected to be produced from the Elk Creek Project: niobium, titanium, scandium and rare earths. These market studies analyzed relevant factors, including supply and demand trends, in order to forecast market pricing. For scandium and the heavy rare earths dysprosium and terbium, for example, the relevant market studies describe a bifurcated market between China and the rest of the world as a result of export controls implemented by China, which has resulted in prices outside of China to be significantly higher than prices within China. In the judgment of the qualified person, various assumptions were applied to the forecasted market pricing to arrive at the realized pricing used in the economic analysis, including, without limitation, terms of the offtake arrangements pursuant to which NioCorp expects to sell its products. Refer to Sections 16 and 19 of the 2026 S-K 1300 Elk Creek Technical Report Summary for additional information regarding market and netback pricing assumptions for each product. Description Realized Price $/lb product FeNb $ 23.59 Sc O (LoM average) 1,562.90 TiCl 0.84 NdPr Oxide 62.78 Tb O 2,048.21 Dy O 593.30 SEG Carbonate 4.07 Heavies Carbonate 2.29 2 2 3 4 2 3 4 2 3 2 3
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33 Capital Cost Estimates The following table shows the breakout in LoM initial capital and sustaining capital cost estimates (including closure and reclamation of $96 million), which total $4,019 million. This includes a total initial capital cost of $1,849 million, including a $233 million contingency, equal to an overall contingency of 14% on initial capital. ($millions) Description Initial Sustaining Total Capitalized Preproduction Expenses $ 3 $ — $ 3 Site Preparation and Infrastructure 25 42 67 Processing Plant 870 309 1,180 Water Management & Treatment 13 0 13 Mining Infrastructure 145 382 527 Tailings Management 57 169 226 Site Wide Indirects 4 — 4 Processing Indirects 34 — 34 Mining Indirects 169 1,000 1,169 Owner's Costs Indirects 296 3 299 Closure and Reclamation — 96 96 Contingency 233 169 402 Total Capital Costs $ 1,849 $ 2,170 $ 4,019 Totals may not sum due to rounding. Operating Cost Estimates The following LoM unit operating cost estimates include the pre-production and first/last years of production. Description LoM $/ton ore Mining Cost $ 70.95 Process Cost 151.96 Water Mgmt 13.72 Tailings 8.08 Other Infrastructure 9.52 Site G&A 0.32 Subtotal 254.56 Royalties/Annual Bond Premium 11.38 Total LoM Operating Costs $ 265.94 Totals may not sum due to rounding.
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34 Summary Projected Economic Results Description Value Pre-Tax NPV ($ millions) $ 4,111 Pre-Tax IRR 24.0% After-Tax NPV ($ millions) $ 3,441 After-Tax IRR 22.8% After-Tax Payback Period (years) 2.93 Total Upfront Capital Expenditures ($ millions) $ 1,849 Mine Life (years) 40 LoM Gross Revenue ($ millions) $ 37,435 Niobium 9,781 Scandium 14,331 Titanium 3,946 Rare Earths 9,378 NdPr Oxide 3,255 Dy Oxide 3,137 Tb Oxide 2,827 SEG Carbonate 113 Heavy Rare Earth Carbonate 46 Average Annual EBITDA over Full Production Years ($ millions)(1) $ 608 Average EBITDA Margin over LoM (EBITDA as a % of total revenue) (1) 67% Revenue Per Ton ($/ton) $ 815 Average Annual Operating Cost ($/ton) $ (255) Effective Tax Rate 14.3% Development Timeline (months) 35 Totals may not sum due to rounding. (1) The term “EBITDA” refers to earnings before interest, taxes depreciation and amortization. See “Non-GAAP Financial Performance Measures” below for a discussion of the use of non-GAAP financial measures. (2) Taxes that may be levied on the Elk Creek Project include corporate income tax rates of 21% for federal and 3.99% for Nebraska. The Elk Creek Project is eligible for federal depletion allowances and credits, as well as various state incentives. The calculated effective income tax rate for the Elk Creek Project is 14.3% for the 2026 Elk Creek Study. Planned Operations Planned Mining Operations The Elk Creek Project is planned as an underground mining operation using a long-hole stoping mining method and paste backfill, with ramp access from the surface. The mine will utilize jumbo drills for lateral development and tophammer and down-the-hole drills for vertical development and production stoping. Rock bolters will be used for ground support and probe holes will be used to support mine grouting where required. Ore will be remotely mucked from the bottom stope accesses using 10.3 cubic yard (7.9 cubic meter) battery- electric load-haul-dump units with an 18 metric tonne ("tonne") (19.8 ton) payload capacity and remote-operation capability. Ore will be transported to ore passes equipped with grizzly screens. The ore passes will report to the bottom of each of three mining horizons where the ore will be loaded on to the Railveyor system for transport to the surface plant. The Railveyor is a series of connected ore cars mounted on a rail system that move ore and waste rock from three loading stations underground to two stockpiles on the surface. Planned Processing Operations Planned ore processing operations include mineral processing, hydrometallurgical processing (“Hydromet”), and pyrometallurgical processing (“Pyromet”) housed in separate buildings. 8% 8%
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35 The mineral processing building will house all of its equipment within a single large building. Ore from the Primary Crusher (located adjacent to the mineral processing plant on the surface) will be fed to the secondary cone crusher system, operating in closed circuit with a double deck screen. The screen undersize from the cone crusher system will be fed to a high-pressure grinding roll unit (“HPGR”), operating in closed circuit with another double deck screen. The HPGR screen undersize is the comminution product that will report to the Hydromet process. The Hydromet plant building will be a multi-level engineered steel structure, which will house equipment on two levels. Ore from mineral processing will be fed through a series of processes required to separate the niobium, scandium, titanium and rare earths from the rest of the ore. Outputs from the Hydromet process include saleable TiCl4 and Sc2O3 along with five rare earth oxide/carbonate products, with Nb2O5 reporting to the Pyromet plant for final processing. The Hydromet plant will be supported by a hydrochloric acid regeneration operation. The Pyromet building will house its equipment within a single building. The purpose of the Pyromet plant is to reduce the Nb2O5 coming from the Hydromet plant by converting it into a saleable FeNb metal. Aluminum shots and iron oxide pellets will be introduced to an electric arc furnace on a continuous basis along with fluxing agents and Nb2O5 to produce a saleable ferroniobium metal. Proposed Production Plan and Schedule Based on the 2026 S-K 1300 Elk Creek Technical Report Summary, the operating mine life is approximately 40 years with a nominal processing rate of 3,047 tons per day. The Elk Creek Project timeline is based on 30 months to mechanical completion after authorization to proceed, plus an additional five months of commissioning and ramp-up to 100% of production capacity for a total of 35 months and assumes no financing constraints. The Board must approve a construction program and budget before construction of the Elk Creek Project can begin. This approval, along with the receipt of all required governmental permits and approvals and the completion of project financing, will determine whether and when construction of the Elk Creek Project can begin. Proposed Tailings Storage The tailings produced by the process plant will consist of calcium carbonate, magnesium carbonate, iron oxide, leach residue, gypsum, and slag. Six engineered and lined tailings storage facilities (“TSFs”) will be constructed sequentially to contain the tailings over the life of the Elk Creek Project and have a design capacity of approximately 33.7 million tonnes, against a required capacity over the life of the Elk Creek Project of approximately 31 million tonnes. A composite lining system with leak detection and monitoring systems will be installed in each tailings impoundment. Tailings will be delivered to the TSFs from the paste tailings plant as paste containing low quantities of binder (cement and flyash) to limit seepage. Facility closure is considered in the design. Proposed Salt Management The crystalline salt produced as a waste product of heating and evaporating brine from the reverse osmosis (“RO”) water treatment plant will be transported to a dedicated salt management cell. A single lined surface impoundment, which will also serve as the mine water holding pond during construction, will be constructed to contain the salt over the life of the project and is designed with a volume of approximately 16 million cubic feet. Based on expected flows, the cell is expected to reach its nominal storage capacity, inclusive of a 15% safety factor, in approximately 15 years. NioCorp expects to reduce and reuse salt from the wastewater treatment process and to contract with local landfills to accept a portion of this waste as needed. The cell will incorporate a synthetic liner meeting the requirements of Nebraska Title 123 governing the design, operation and maintenance of wastewater works. Proposed Water Management For the first several years of construction, the advancement of the underground workings will require limited dewatering, anticipated to be through lower-level sumping and pumping for surface collection and disposal. Formation water produced during construction is expected to be brackish and unsuitable for direct discharge and will be stored in the lined salt management cell or trucked off-site for treatment at a local publicly owned treatment works. Excess water in the salt management cell will be spray evaporated within its footprint using turbomister spray evaporators, to avoid the reintroduction of soluble salts into the water treatment system. Temporary on-site storage or off-site shipment and disposal of the crystallized solid waste may be necessary until construction of the salt management cell is completed.
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36 Once full operations commence, a shortfall of approximately 1,000 gallons per minute of operational and processing water is anticipated. To make up this shortfall, NioCorp would purchase fresh water from a local utility and from local landowners. Once tailings begin being deposited in the TSF, internal contact water (from residual moisture in the tailings and precipitation falling within the impoundment footprint) will need to be actively managed. This water will be collected and treated using lime softening to precipitate hydroxide and carbonate solid forms for many of the inorganic constituents. The treated water will be filtered to remove the solids (which will be returned to the TSF for disposal), and the clean water will be pumped to the process plant RO system for further treatment. The clean water from the process plant RO unit will be used in the process plant, and the reject concentrate will be crystallized and deposited into the salt management cell. Proposed Source of Power On-site power will be provided by a third-party microgrid based off modular 2.5 MW natural gas fired generators, rated at approximately 50 MW. A small amount of grid power (200 kW) will also be used. Proposed Source of Natural Gas Natural gas, to be used throughout the Elk Creek Project during the construction and operation phases of the project, will be brought to the site via pipeline from the local gas utilities. NioCorp will connect to existing distribution pipelines located 5 miles east and approximately 30 miles west of the project site. Natural gas will be distributed to all on-site facilities utilizing buried high-density polyethylene natural gas distribution pipe. Natural gas piping above ground and located inside of the facilities will consist predominately of carbon steel pipe. Natural gas will be used for power generation, facility heating, water heating, and for gas-fired process equipment. Environmental, Permitting, and Social The current mine design incorporates the following strategies and technologies designed to minimize environmental impacts of operation: • Zero Process Liquid Discharge: The Elk Creek facility will now operate as a “Zero Process Liquid Discharge” facility, with no releases of process liquids. Instead, both naturally occurring, brackish (slightly salty) water produced during mining operations, and water used in ore processing, will be treated on site for use in operations. A solid salt will be produced from water treatment operations which will be stored on site. • Additional Protection of Groundwater Resources Through Grouting: The Elk Creek Project’s new mine design will utilize grouting during mine development and mine operations to protect groundwater resources in the area and limit the amount of groundwater that will report to the underground mine. • Avoidance of Permanent Impacts to Federally Jurisdictional Waters: The layout of the Elk Creek Project was designed to minimize permanent impacts to any federally jurisdictional waters and/or wetlands on the property. The proposed design of TSF Cell #3 would result in permanent impacts to a federally jurisdictional intermittent channel requiring CWA Section 404 permitting. If the design remains unchanged and the channel status remains jurisdictional at the time of construction, the permanent impacts would require federal permitting. This overall layout minimized the expected environmental impacts. No other federal permits are now expected to be required for the Elk Creek Project. • Utilizing Tailings as Underground Mine Backfill: The plan to fill underground voids concurrently with mining operations using a paste backfill material that contains mine waste material that typically would be stored in above-ground tailings storage areas. The tailings will be combined with cement and/or flyash to provide a structural backfill in the mine which allows for a more efficient extraction of the mineral reserve. A number of key permits and environmental management requirements have been identified for the Elk Creek Project, some of which need to be implemented as soon as practicable in order to maintain the proposed Elk Creek Project schedule. • While not necessarily complex, the timing generally required to complete permitting through any federal regulatory agency requires that NioCorp engage key agencies (in this case the USACE and possibly the EPA) early on in Elk Creek Project development and consider the siting and orientation of facilities carefully to minimize the risk of a protracted National Environmental Policy Act analysis of the Elk Creek Project. At the present time, the Company believes that we have completed the major federal permitting actions needed for project construction, although changes to the design or location of project facilities may require that additional federal permits be obtained.
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37 • Construction at the facility requires an Air Permit from the State of Nebraska, which was issued to the Company on June 2, 2020. The Air Permit describes all the prospective air emissions from the facility and required the completion of an air quality model that demonstrates compliance with the NAAQS. On April 15, 2022, the Company announced that the Nebraska Department of Environment and Energy advised the Company that periodic extensions to the Elk Creek Project’s Air Permit are no longer required because the Company has met the regulatory definition of “construction, reconstruction, or modification of the source” since the permit was issued. • Documentation of existing baseline environmental conditions at the Elk Creek Project site was initiated in 2014 and will continue as needed throughout the permitting process. • Surface water monitoring will continue as needed throughout the permitting process and extend into construction and operations as part of the Environmental Management System and likely State of Nebraska permit requirements. • The major land-use authorization for the project was received from Johnson County, Nebraska, on December 24, 2019, in the form of a Special Use Permit for the project. This land-use permit is a necessary precursor to any project-related construction activities. County zoning permits will be required for individual buildings constructed at the site, and the County requirement is that such applications must be submitted five days before construction commences. • Closure costs for the Elk Creek Project have been estimated at $106 million, including contingency, which covers all aspects of closure and site reclamation and includes a three-year closure period and a 30-year post-closure monitoring period. The Company has not identified any significant encumbrances to the property it owns or holds under OTP agreements. Other than for the MSHA assessment described in Exhibit 95.1 to this Annual Report on Form 10-K, the Company has not had any permit violations or fines since the filing of our Annual Report on Form 10-K for the fiscal year ended June 30, 2025. Permitting requirements for the project have been identified. The Company holds an Air Construction Permit from the State of Nebraska and a Special Use Permit from Johnson County, both of which are necessary to allow the start of project construction. In addition, the Elk Creek Project will be required to obtain a series of permits for operations from federal, state, and local agencies. The majority of these permits are ministerial in nature and present minimal risk to the Company and typically involve the completion of an application and the payment of a nominal fee. Four permits from the State of Nebraska are discretionary in nature, where an application and fee are provided to the state and the state must make a decision as to whether or not the permit will be granted. In addition, one federal permit, from the USACE is discretionary as well. While the risk involved in these five permits is low, such discretionary permits require more processing time and do require the agency (either the State of Nebraska or the USACE) to make a decision in favor of issuance of the permit. These five permits include the following: • Solid Waste Permit; • Air Construction Permit for the microgrid, the obtaining, maintenance and costs of which will be the responsibility of the third- party microgrid operator; • Air Operating Permits for the facility; • Air Operating Permit for the microgrid; and • USACE permit for the diversion channel associated with the construction of TSF #3 The cost and schedule for obtaining both the discretionary and ministerial permits is included in the overall execution plan for the Elk Creek Project. Additional details on the project’s permitting requirements can be found in Section 17 of the 2026 S-K 1300 Elk Creek Technical Report Summary. Mineral Reserves and Resources Mineral reserves and mineral resources at the Elk Creek Project as of June 30, 2026, are summarized in the tables below. Further discussion and background regarding the approaches used to establish mineral reserves and mineral resources is contained in Sections 11 and 12 of the 2026 S-K 1300 Elk Creek Technical Report Summary. Elk Creek Project In Situ Mineral Resource Estimate Excluding Reserves as of June 30, 2026
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38 Classification Cut-off NSR ($/ton) Tonnage (Mtons) Nb₂O₅ (%) TiO₂ (%) Sc (ppm) TREO (%) Measured 218 14.1 0.53 2.05 47.60 0.39 Indicated 218 149.0 0.43 1.70 42.50 0.39 Measured + Indicated 218 163.1 0.44 1.89 45.30 0.39 Inferred 218 169.2 0.38 2.14 51.02 0.39 Notes: (1) Mineral resources are not mineral reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the mineral resource will be converted to mineral reserves. (2) Prepared in accordance with S-K 1300. (3) NSR cut-off of $218/ton ($240/tonne) based on longhole stoping underground mining; incorporates metallurgical recoveries of Nb 86.72%, TiO₂ 83.65%, Sc 92.00%, and REE by-products 92.00%, at metal prices of $52.00/kg Nb, $2,000.00/kg Sc, $1.86/kg TiCl4, $1,845.00/kg Tb₂O₃, $125.00/kg NdPr, and $8.97/kg SEG carbonate. (4) TREO = Light Rare Earth Metals and Oxides + Heavy Rare Earth Metals and Oxides expressed as a percentage (TREO% = TREO ppm ÷ 10,000). (5) Tonnages in millions of short tons (Mtons). Grades rounded to reflect the approximate nature of resource estimates. (6) Totals may not sum due to rounding. (7) Qualified Person: Dahrouge Geological Consulting USA Ltd., effective date June 30, 2026. Elk Creek Project Underground In Situ Mineral Reserves Estimate for Elk Creek as of June 30, 2026 Mineral Reserve Classification Cut-off NSR Tonnage Grade Grade Grade Grade ($/ton) (ton) (Nb2O5%) (TiO2%) (Sc ppm) (TREO %) Proven 218 7,570,098 0.760 2.70 71.5 0.32 Probable 218 38,359,365 0.759 2.67 68.8 0.35 Total 218 45,929,462 0.759 2.68 69.3 0.34 Classification Tonnage(ton) NbO Gr ade (%) FeNb (ton) Payable Nb (ton) TiO Grad e (%) Payable TiCl (ton) Sc Grade (ppm) Payable Sc O (ton) TREO Grade (ppm) Payable TREO (ton) Proven 7,570,098 0.76 53,651 34,873 2.70 405,938 71.5 762 3,232 22,509 Probable 38,359,365 0.76 271,386 176,401 2.67 2,036,334 68.8 3,717 3,489 123,115 Total 45,929,462 0.76 325,038 211,274 2.68 2,442,272 69.3 4,479 3,446 145,625 Notes: (1) All figures are rounded to reflect the accuracy of the estimates. Totals may not sum due to rounding. (2) The Qualified Person for the mineral reserve estimate is Amplify Mine Planning. The estimate has an effective date of June 30, 2026. (3) The mineral reserve is based on the mine design and mine plan, utilizing an average cut-off grade of 0.650% Nb2O5 with an NSR of $ 218/ton. (4) The estimate of mineral reserves may be materially affected by metal prices, environmental, permitting, legal, title, taxation, socio-political, marketing, infrastructure development, or other relevant issues. (5) Annual LoM average production rate of ~8,282 tons of FeNb/annum in the years of full production. (6) Mining dilution of ~6% was applied to all stopes and development, based on 3% for the primary stopes, 9% for the secondary stopes, and 5% for ore development. (7) Mining recoveries of 95% were applied in longhole stopes and 62.5% in sill pillar stopes. (8) Price assumptions for FeNb, Sc2O3, TiO2 and TREO metals are based upon independent market analyses for each product. (9) Price and cost assumptions are based on the pricing of products at the “mine-gate,” with no additional down-stream costs required. The assumed products are a ferroniobium product (metallic alloy shots consisting of 65%Nb and 35% Fe), titanium in the form of TiCl4, scandium trioxide in powder form and rare earth oxides in either purified oxide or carbonate form. The mineral reserve has an average LoM NSR of $590.84/ton. (10) The economic assumptions used to define the mineral reserve cut-off grade are as follows: 2 5 2 4 2 3
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39 Parameter Value Unit Mining Cost $46.14 $/ton mined Processing 125.04 $/ton mined Water Management and Infrastructure 16.58 $/ton mined Tailings Management 2.00 $/ton mined Other Infrastructure 5.46 $/ton mined General and Administrative 8.89 $/ton mined Royalties/Annual Bond Premium 8.32 $/ton mined Other Costs 6.28 $/ton mined Total Cost $218.71 $/ton mined Nb O to Niobium conversion 69.9 % Niobium Process Recovery 86.72 % Niobium Price $23.59 $/lb TiCl Process Recovery 83.65 % TiCl Price $0.84 $/lb Sc Process Recovery 92 % Sc to Sc O conversion 153.4 % Sc Price $891.76 $/lb Dy O Process Recovery 92 % Dy O Price $185.97 $/lb Nd O Process Recovery 92 % Nd O Price $56.70 $/lb Pr O Process Recovery 92 % Pr O Price $56.70 $/lb Tb O Process Recovery 92 % Tb O Price $836.88 $/lb Comparison of Mineral Resources and Mineral Reserves to Previous Estimates The mineral resource and mineral reserve estimates reported in the 2026 S-K 1300 Elk Creek Technical Report Summary supersede the previous mineral resource and mineral reserve estimates reported in our Annual Report on Form 10-K for the fiscal year ended June 30, 2025, which was based on the 2022 S-K 1300 Elk Creek Technical Report Summary. The principal changes between the 2025 and 2026 resource estimates are as follows. The NSR cut-off was raised from $164/ton ($180/tonne) to $218/ton ($240/tonne), reflecting updated operating cost estimates from the 2026 Elk Creek Study. A measured mineral resource category of 14.1 Mtons (12.8 million metric tonnes ("Mtonnes")) was introduced in the 2026 estimate, representing areas where infill drilling achieved sufficient density to support measured classification; no measured resource was classified in 2025. Indicated tonnage decreased from 167.2 Mtons (151.7 Mtonnes) in the 2025 estimate to 149.0 Mtons (135.2 Mtonnes) in the 2026 estimate (-10.8%), primarily due to the reclassification of indicated resources uplifted into the measured classification. Inferred tonnage increased from 119.4 Mtons (108.3 Mtonnes) in the 2025 estimate to 169.2 Mtons (153.5 Mtonnes) in the 2026 estimate (+41.7%), reflecting additional drilling that extended the geological understanding of the peripheral carbonatite capturing a greater volume of lower-grade peripheral material. Mean grades are broadly consistent between estimates; the slight improvement in indicated TiO₂ (2.24% to 2.36%) and TREO (0.34% to 0.36%) reflects the higher NSR cut-off removing lower-grade diluting blocks from the reported indicated resource. In terms of the mineral reserve, a proven reserve of 7.6 Mtons (6.9 Mtonnes) was established for the 2026 estimate; no proven reserve was classified in 2025. Probable reserves decreased from 40.4 Mtons (36.6 Mtonnes) in the 2025 estimate to 38.4 Mtons (34.8 Mtonnes) in the 2026 estimate (-5.1%). Grades were broadly comparable between the 2025 and 2026 reserve estimates. The change between the two estimates is a reflection of the infill drilling program completed in 2025, which specifically targeted uplifting a portion of the probable reserves into the proven category. Non-GAAP Financial Performance Measures Non-GAAP financial performance measures are intended to provide additional information only and do not have any standard meaning prescribed by U.S. GAAP. These measures should not be considered in isolation or as a substitute for performance measures prepared in accordance with U.S. GAAP. The 2026 S-K 1300 Elk Creek Technical Report Summary uses non-GAAP financial performance measures, such as EBITDA, Averaged Annual EBITDA, and Averaged EBITDA Margin, for purposes of projecting the economic results of the Elk Creek Project. We are unable to provide a reconciliation of these forward-looking non-GAAP measures to the most comparable U.S. GAAP financial performance measures because certain information needed to reconcile those non-GAAP measures to the most comparable U.S. GAAP financial performance measures is dependent on future events, some of which are outside the control of the Company, such as FeNb, Sc2O3, and TiO2 prices, interest rates, and exchange rates. Moreover, 2 5 4 4 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3
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40 estimating such U.S. GAAP measures with the required precision necessary to provide a meaningful reconciliation is extremely difficult and could not be accomplished without unreasonable effort. Proposed Activities The Elk Creek Property is characterized as a development stage property. The Company is currently progressing the property toward construction while it works to secure the remaining project financing required to fund the construction, commissioning, and operation of the Elk Creek Project. The property is expected to be characterized as a production stage property upon the commencement of production. Using cash on hand, the Company expects to undertake the following activities: • Continuation of the Company's efforts to secure federal, state and local operating permits; • Negotiation and completion of offtake agreements for the remaining uncommitted production of Nb, Sc, and Ti from the Elk Creek Project, including the potential sale of Ti as titanium tetrachloride, as well as REE production; • Negotiation and completion of engineering, procurement, and construction agreements; • Completion of the final detailed engineering for the underground portion of the Elk Creek Project; • Continuation and completion of the final detailed engineering for surface project facilities; • Completion of water supply agreements and related infrastructure to deliver fresh water to the project site; and • Continuation of revised mine groundwater investigation and control activities. Securing the remaining project financing is a condition to the Company making a final investment decision to proceed with full construction of the Elk Creek Project. Upon obtaining such financing, we expect to undertake the following activities: • Construction of natural gas and electrical infrastructure under existing agreements to serve the Elk Creek Project site; • Initiation of long-lead equipment procurement activities; and • Initiation of initial construction work at the project site. Corporate Headquarters We lease our principal executive office space at 7000 South Yosemite Street, Suite 115, Centennial, Colorado. ITEM 3. LEGAL PROCEEDINGS As of September 25, 2026, we are not a party to any legal proceedings that could have a material adverse effect on the Company’s business, financial condition, or operating results. Further, to the Company’s knowledge, no such proceedings have been threatened against the Company. ITEM 4. MINE SAFETY DISCLOSURES Pursuant to Section 1503(a) of the United States Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd- Frank Act”), issuers that are operators, or that have a subsidiary that is an operator, of a coal or other mine in the U.S. are required to disclose specified information about mine health and safety in their periodic reports. These reporting requirements are based on the safety and health requirements applicable to mines under the Federal Mine Safety and Health Act of 1977 (the “Mine Act”) which is administered by MSHA. The information concerning mine safety violations and other regulatory matters required by Section 1503(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act and Item 104 of Regulation S-K is included in Exhibit 95.1 to this Annual Report on Form 10-K.
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41 PART II ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS, AND ISSUER PURCHASES OF EQUITY SECURITIES Market Information The Common Shares are listed for trading on the Nasdaq under the trading symbol “NB.” The Company also trades on the Frankfurt Stock Exchange as “BR30.” Holders As of September 25, 2026, we had 140 holders of record of our Common Shares. Dividends We have not paid any cash dividends on the Common Shares since our inception and do not anticipate paying any cash dividends in the foreseeable future. We plan to retain our earnings, if any, to provide funds for the expansion of our business. Securities Authorized for Issuance Under Equity Compensation Plans See Equity Compensation Plan Information under Item 12, “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters,” for information on plans approved by our shareholders. Purchases of Equity Securities by the Company We did not make any repurchases in the quarter ended June 30, 2026. Recent Sales of Unregistered Securities The Company did not make any unregistered sales of equity securities during the quarter ended June 30, 2026. Exchange Controls There are no governmental laws, decrees, or regulations in Canada that restrict the export or import of capital, including foreign exchange controls, or that affect the remittance of dividends, interest or other payments to non-resident holders of the securities of NioCorp, other than Canadian withholding tax. See “Certain Canadian Federal Income Tax Considerations for U.S. Residents” below. Certain Canadian Federal Income Tax Considerations for U.S. Residents The following generally summarizes certain Canadian federal income tax consequences generally applicable under the Income Tax Act (Canada) and the regulations enacted thereunder (collectively, the “Canadian Tax Act”) and the Canada-United States Tax Convention (1980) (the “Convention”) to the holding and disposition of Common Shares. Comment is restricted to holders of Common Shares each of whom, at all material times for the purposes of the Canadian Tax Act and the Convention, (i) is resident solely in the U.S. for tax purposes, (ii) is a “qualifying person” under and entitled to the benefits of the Convention, (iii) holds all Common Shares as capital property, (iv) deals at arm’s length with and is not affiliated with NioCorp, (v) does not and is not deemed to use or hold any Common Shares in a business carried on in Canada (including an adventure or concern in the nature of trade), (vi) is not an insurer that carries on business in Canada and elsewhere, (vii) is not an “authorized foreign bank” (as defined in the Canadian Tax Act), (viii) has not entered into a “derivative forward agreement,” “synthetic equity arrangement,” or “synthetic disposition arrangement” (each as defined in the Canadian Tax Act) with respect to the Common Shares, and (ix) does not have and has not had, at any time, a “permanent establishment” (as defined in the Convention) of any kind in Canada (each such holder, a “U.S. Resident Holder”). Certain U.S.-resident entities that are fiscally transparent for U.S. federal income tax purposes (including limited liability companies) may not in all circumstances be entitled to the benefits of the Convention. Members of or holders of an interest in such an entity that holds Common Shares should consult their own tax advisers regarding the extent, if any, to which the benefits of the Convention will apply to the entity in respect of its Common Shares.
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42 Generally, a U.S. Resident Holder’s Common Shares will be considered to be capital property of such holder provided that the U.S. Resident Holder is not a trader or dealer in securities, did not acquire, hold, or dispose of the Common Shares in one or more transactions considered to be an adventure or concern in the nature of trade (i.e. speculation), and does not hold the Common Shares in the course of carrying on a business. This summary is based on the current provisions of the Canadian Tax Act and the Convention in effect as of the date prior to the date hereof, all specific proposals to amend the Canadian Tax Act and the Convention publicly and officially announced by or on behalf of the Minister of Finance (Canada) prior to the date hereof (the "Tax Proposals"), and the current administrative policies and assessing practices of the Canada Revenue Agency (the “CRA”) published in writing and made publicly available by the CRA prior to the date hereof. This summary assumes that the Tax Proposals will be enacted as currently proposed, and that there will be no other material change to any applicable law or administrative policy or assessing practice, whether by way of judicial, legislative or governmental decision or action, although no assurance can be given in these respects. Except as otherwise expressly provided, this summary does not take into account any provincial, territorial, or foreign tax considerations, which may differ materially from those set out herein. This summary is of a general nature only, is not exhaustive of all possible Canadian federal income tax considerations and is not intended to be and should not be construed as legal or tax advice to any particular U.S. Resident Holder, and no representations with respect to the tax consequences to any U.S. Resident Holder are made herein. The tax consequences of holding and disposing of Common Shares will vary according to the U.S. Resident Holder’s particular circumstances. U.S. Resident Holders are urged to consult their own tax advisers for advice with respect to their particular circumstances. The discussion below is qualified accordingly. Currency Conversion In general, for purposes of the Canadian Tax Act, all amounts relating to the holding or disposition of Common Shares must be converted into Canadian dollars based on the relevant exchange rate as determined in accordance with the Canadian Tax Act. Disposition of Common Shares A U.S. Resident Holder generally will not be subject to tax under the Canadian Tax Act in respect of a capital gain realized on the disposition or deemed disposition of one or more Common Shares, nor will a capital loss arising therefrom be recognized under the Canadian Tax Act, unless such Common Shares constitute “taxable Canadian property” (as defined in the Canadian Tax Act) of the U.S. Resident Holder at the time of disposition and the U.S. Resident Holder is not entitled to relief under the Convention. Generally, a U.S. Resident Holder’s Common Shares will not constitute “taxable Canadian property” of such holder at a particular time at which the Common Shares are listed on a “designated stock exchange” (which currently includes Nasdaq) unless at any time during the 60-month period that ends at the particular time both of the following conditions are concurrently met: 1. 25% or more of the issued shares of any class of the capital stock of NioCorp were owned by or belonged to one or any combination of: a. the U.S. Resident Holder, b. persons with whom the U.S. Resident Holder did not deal at arm’s length, and c. partnerships in which the U.S. Resident Holder or a person referred to in clause (b) holds a membership interest directly or indirectly through one or more partnerships, and 2. more than 50% of the fair market value of the Common Shares was derived directly or indirectly from, one or any combination of, real or immovable property situated in Canada, “Canadian resource properties” (as defined in the Canadian Tax Act), “timber resource properties” (as defined in the Canadian Tax Act), or options in respect of, or interests in, or for civil law rights in, any of the foregoing, whether or not the property exists. Notwithstanding the foregoing, Common Shares may also be deemed to be “taxable Canadian property” in certain circumstances set out in the Canadian Tax Act. U.S. Resident Holders whose Common Shares are or may be “taxable Canadian property” should consult their own tax advisors with respect to the tax and compliance considerations that may be relevant to them, including with respect to any potential relief under the Convention.
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43 Dividends on Common Shares A U.S. Resident Holder to whom NioCorp pays or credits or is deemed to pay or credit a dividend on such holder’s Common Shares will be subject to Canadian withholding tax, and NioCorp will be required to withhold the tax from the dividend and remit it to the CRA for the holder’s account. The rate of withholding tax under the Canadian Tax Act is 25% of the gross amount of the dividend, but should generally be reduced under the Convention to 15% (or, if the U.S. Resident Holder is a company which is the beneficial owner of at least 10% of the voting stock of NioCorp, 5%) of the gross amount of the dividend. For this purpose, a company that is a resident of the United States for purposes of the Canadian Tax Act and the Convention and is entitled to the benefits of the Convention shall be considered to own the voting stock of NioCorp owned by an entity that is considered fiscally transparent under the laws of the United States and that is not a resident of Canada, in proportion to such company’s ownership interest in that entity. ITEM 6. RESERVED
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44 ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS The following Management’s Discussion and Analysis (“MD&A”) provides information that management believes is relevant to an assessment and understanding of the consolidated financial condition and results of operations of NioCorp and subsidiaries. This item should be read in conjunction with our consolidated financial statements and the notes thereto included in this Annual Report on Form 10- K. Summary of Consolidated Financial and Operating Performance The Company had no revenues from mining operations during the fiscal years presented below. Operating expenses incurred related primarily to performing exploration and feasibility study related activities, as well as the activities necessary to support corporate and shareholder duties. For the year ended June 30, 2026 2025 ($000) Operating expenses $ 38,309 $ 11,958 Net loss attributable to the Company (48,555) (17,405) Net loss per share (basic and diluted) (0.41) (0.36) The net loss attributable to the Company increased to $48.6 million for fiscal year 2026 from $17.4 million for fiscal year 2025. This is primarily due to spending on the 2026 Elk Creek Study, the recognition of non-cash expenses related to share-based compensation and the valuation of the Earnout Shares and Warrant liabilities, and increased compensation expenses, partially offset by interest income. Net loss per share increased due to an increase in net loss, offset by an increase in weighted average Common Shares outstanding since June 30, 2025. Results of Operations The Company had no revenues from mining operations during the fiscal years presented below. Operating expenses incurred related primarily to performing exploration and study related activities, and the activities necessary to support corporate and shareholder duties, as detailed in the following table: For the year ended June 30, 2026 2025 ($000) Operating expenses: Exploration expenditures $ 16,076 $ 4,135 General and administrative expenditures 22,233 7,823 Total operating expenses 38,309 11,958 Change in fair value of earnout shares liability 8,571 2,063 Change in fair value of warrant liabilities 13,034 4,093 Change in fair value of convertible notes — 40 Interest expense — 48 Interest income (9,146) (94) Other non-operating expense (income) 13 (126) Income tax benefit — — Less: Net loss attributable to redeemable noncontrolling interest (2,226) (577) Net loss attributable to the Company $ (48,555) $ (17,405) Fiscal Year 2026 as Compared to Fiscal Year 2025 Significant items affecting operating expenses are noted below: Exploration expenditures increased for fiscal year 2026 as compared to fiscal year 2025 primarily due to field-based costs associated with the 2025 Drilling Program, which was substantially completed by September 30, 2025, as well as expenses related to the Company’s ongoing efforts to prepare the 2026 Elk Creek Study.
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45 General and administrative expenditures increased in fiscal year 2026 as compared to fiscal year 2025, reflecting an overall increase in corporate compliance, governance, financing, and other Elk Creek Project advancement activities. This includes increased expenses related to share-based compensation and employee compensation costs, legal fees to support financing initiatives and Elk Creek Project advancement, and costs associated with the advancement of scandium product initiatives. Other significant items impacting the change in the Company’s net loss are noted below: Change in fair value of earnout shares liability represents the impact of changes in fair value related to valuation of the Earnout Shares. The increase in fair value for fiscal year 2026 as compared to fiscal year 2025 primarily reflects the increase in the Company’s Common Share price in the financial modeling used to determine the period end fair value. Change in fair value of warrant liabilities represents the impact of changes in fair value of Warrants recorded as liabilities in the consolidated balance sheet. The increase in fair value for fiscal year 2026 as compared to fiscal year 2025 primarily reflects the increase in the Company’s Common Share price used in the Black-Scholes valuation of outstanding Warrant liabilities. Interest income represents earnings from the investment of excess cash balances in a commercial money market account. The increase for fiscal year 2026 as compared to fiscal year 2025 is attributable to our higher cash balance resulting from our financing efforts during fiscal year 2026. Loss attributable to noncontrolling interest represents the portion of net loss in ECRC attributable to the Vested Shares, which are not owned by the Company. The increase in loss for fiscal year 2026 as compared to fiscal year 2025 is related to the increased consolidated net loss, as noted above, incurred by ECRC. Liquidity and Capital Resources Overview As of June 30, 2026, the Company had cash of $415.0 million and working capital of $402.3 million, compared to cash of $25.6 million and working capital of $24.8 million as of June 30, 2025. This increase reflects net proceeds of approximately $375.1 million from five equity offerings completed between July 2025 and February 2026, together with approximately $23.3 million of proceeds from the exercise of Warrants and Options and approximately $38.7 million of proceeds from advances under the Standby Equity Purchase Agreement, dated January 26, 2023 (the “Yorkville Equity Facility Financing Agreement”) between the Company and YA II PN, Ltd., an investment fund managed by Yorkville Advisors Global, LP. The Company has no outstanding long-term debt. For additional details on the equity transactions that occurred during the year-ended June 30, 2026, see Note 9 to the consolidated financial statements included in this Annual Report on Form 10-K. During fiscal year 2026 and the period through the date of this Annual Report on Form 10-K, the Company completed the 2025 Drilling Program that supported updated mineral resource and mineral reserve estimates for the Elk Creek Project, commenced excavation of the mine portal at the Elk Creek Project in February 2026, and completed the 2026 Elk Creek Study. The Company is now focused on securing project financing sufficient to cover initial capital costs and other related expenses necessary for the commencement and completion of construction, and carrying out our near-term planned work programs necessary to complete detailed design, development and construction of the Elk Creek Project, as well as the commencement of early elements of project construction. The Company does not intend to commence full construction of the Elk Creek Project until sufficient project financing is in place to cover initial capital costs and other related expenses necessary for the commencement and completion of construction of the Elk Creek Project. Short-Term Liquidity and Planned Expenditures We expect that the Company will operate at a loss for the foreseeable future. The Company’s current planned cash outflows are approximately $65 million to $75 million for the next twelve months. In addition to the settlement of outstanding accounts payable and other short-term liabilities, our planned cash outflows over the next twelve months are expected to consist of expenditures relating to the advancement of the Elk Creek Project by NioCorp’s majority-owned subsidiary, ECRC, corporate overhead costs, and estimated costs related to securing the financing necessary for construction of the Elk Creek Project. We expect our cash balance as of June 30, 2026, together with the proceeds from the exercise of Warrants and Options, if any, and the reimbursement payments to which ECRC is entitled pursuant to the DoW Agreement, to be sufficient to fund our planned cash outflows for at least the next twelve months from the date of this Annual Report on Form 10-K. That expectation relates to the activities described above and does not extend to the capital required to construct the Elk Creek Project and achieve commercial production, which the Company must finance separately as described under “Long-Term Liquidity
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46 Requirements” below. If project financing is delayed, the Company has the ability to defer or reduce a substantial portion of its planned expenditures until such financing is in place. The planned expenditures relating to the advancement of the Elk Creek Project over the next twelve months include, but are not limited to, continued construction of the mine portal at the Elk Creek Project, which the Company’s Board of Directors approved in December 2025 and for which the current remaining estimated capital cost is approximately $38.7 million; detailed engineering; procurement and construction contracting activities; planning and deposits for long-lead equipment; metallurgical test work; environmental and permitting activities; community and stakeholder engagement programs; and advisory costs relating to securing project financing. The planned corporate overhead costs over the next twelve months are approximately $19 million, including Elk Creek property lease commitments, and the settlement of outstanding accounts payable as of June 30, 2026. Long-Term Liquidity Requirements Our long-term liquidity requirements consist principally of the capital required to construct the Elk Creek Project and to fund the Company’s operations through the commencement of commercial production. On August 10, 2026, the Company announced the results of the 2026 Elk Creek Study, which is summarized in the 2026 S-K 1300 Elk Creek Technical Report Summary. The 2026 S-K 1300 Elk Creek Technical Report Summary includes an estimated total upfront capital expenditure for the Elk Creek Project of approximately $1,849 million, including a contingency of 14%, which is an increase of approximately $708 million compared to the estimated total upfront capital expenditure for the Elk Creek Project of approximately $1,141.0 million that was included in the 2022 S-K 1300 Elk Creek Technical Report Summary. The increase reflects, among other things, a substantially redesigned processing plant and mining operation that is intended to produce eight critical mineral products, from the previous plan to produce three critical mineral products, as well as significant inflationary impacts since the previous feasibility study. The total amount of financing the Company will require is greater than the estimated total upfront capital expenditure for the Elk Creek Project, because the Company must also fund costs that are not included in that estimate. These include financing fees and transaction costs; interest accruing during the development period; working capital required at start-up; reclamation and other financial assurance obligations; corporate overhead costs through the commencement of commercial production; and any cost escalation or cost overruns in excess of the contingency included in the 2026 S-K 1300 Elk Creek Technical Report Summary. The Company would therefore require additional financing to fund that estimated capital expenditure alone, before giving effect to the additional costs described above. The Company does not expect to fund it from any single source. Management currently anticipates that it would be provided by a combination of sources of financing, in the targeted proportions and from the categories of sources described below. The actual amount of capital expenditure required to successfully achieve commercial production at the Elk Creek Project is subject to, among other factors, the timing and actual cost of detailed engineering, procurement, construction contracting, permitting and the construction of infrastructure, mining and processing facilities, as well as prevailing interest rates and the terms on which financing is available to the Company. In addition, to the extent that EXIM or any other prospective lender requests further project activities to be undertaken in connection with its diligence process, the Company would require additional funding to complete such activities. The Company’s ability to construct and operate the Elk Creek Project is dependent on management’s ability to secure such financing. Management currently anticipates that it will fund the upfront capital expenditure amount for the Elk Creek Project through a combination of debt and equity financing, with approximately 65% of such amount being funded from the net proceeds of debt financing, including the amount of debt that would be represented by the EXIM Financing, if any. The balance, representing approximately 35% of such amount, is expected to be funded from the net proceeds of equity financing or other funding available to the Company. The debt component contemplated by this funding mix may exceed the EXIM Financing, as described under “Proposed Project Financing from EXIM” below. In addition to the EXIM Financing, the Company may also seek to fund a portion of the debt component from other export credit agencies and from commercial lenders. The ultimate composition of the debt component has not been determined and may or may not include lenders other than EXIM. The Company has not obtained a commitment for any portion of the debt financing required to construct the Elk Creek Project, and there can be no assurance that debt financing will be available in the amount, or on the terms, that management currently anticipates, or at all. Management is actively pursuing additional sources of debt and equity financing to meet its long-term funding requirements, and while it has been successful in doing so in the past, there is no assurance that we will be able to obtain any such additional financing on acceptable terms, if at all. See Item 1A., Risk Factors – We expect to incur substantial debt in connection with the Elk Creek Project, which will require a significant amount of cash to service, require us to comply with certain covenants and restrictions, and could impair our ability to obtain additional financing. Because the funding mix that management currently anticipates contemplates that approximately 35% of the upfront capital expenditure for the Elk Creek Project would be funded with equity or other funding available to the Company, and because the
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47 Company’s cash on hand as of June 30, 2026 represents less than 35% of the estimated total upfront capital expenditure for the Elk Creek Project, the Company expects that it may be required to raise additional equity capital in order to fund this portion of the Elk Creek Project’s upfront capitalization. The amount of equity capital the Company will be required to raise will depend on, among other things, the final upfront capital cost of the Elk Creek Project, the amount and terms of the debt financing the Company is able to obtain, and the minimum equity contribution, leverage limitations and coverage ratios that prospective lenders require. See Item 1A., Risk Factors –We will require significant additional capital to fund our business plan. Proposed Project Financing from EXIM The estimated financing costs associated with the Elk Creek Project over the next twelve months include, but are not limited to, costs relating to the EXIM application process, the scope of which remains under discussion with EXIM. On June 6, 2023, the Company announced that it had submitted an application to EXIM for debt financing, which may include a loan or loan guarantee, to fund the project costs for the Elk Creek Project, under EXIM’s “Make More in America” initiative. The Company was informed that its application received approval by the first of three reviews by the EXIM Transaction Review Committee ("TRC") on October 2, 2023. In April 2024, EXIM provided the Company with a PPL, which also conveyed EXIM’s initial due diligence findings on the Company’s application. The PPL did not state a total amount of the EXIM Financing. Instead, the PPL provided that the amount of the EXIM Financing that could be made available for the Elk Creek Project will be scaled based on the number of U.S. jobs supported, both during construction and over the life of EXIM’s financing, and subject to certain expectations regarding the ratio of debt-to-equity financing for the Elk Creek Project. PPL also identified additional project activities to be undertaken by the Company as part of EXIM’s due diligence process, including, among other things, an updated mine plan and updated Elk Creek Project capital costs on a final or close-to-final basis reflecting updated process flows. On February 4, 2025, EXIM advanced the Company’s application to the next stage of the TRC’s reviews and selected RPMGlobal USA, Inc. whose mining advisory business has since been acquired by SLR Consulting, to conduct an independent technical review of the Elk Creek Project, and in October 2025 the Company executed a professional services agreement with SLR Consulting to conduct an independent environmental and social review as part of EXIM’s ongoing due diligence. The Company’s application remains at the next stage of the TRC’s review process. If the application is approved and supported by EXIM staff, it would be subject to a final decision by EXIM’s Board of Directors. The amount of the EXIM Financing, if any, will be determined by EXIM. As described above, the PPL provided that the amount of the EXIM Financing that could be made available for the Elk Creek Project will be scaled based on the number of U.S. jobs supported, both during construction and over the life of EXIM’s financing, subject to certain expectations regarding the ratio of debt-to-equity financing for the Elk Creek Project. That determination will be made by EXIM on the basis of its own analysis and its own application of its underwriting criteria and internal policies. The Company does not control that analysis, is not able to predict its outcome, and accordingly is unable to estimate the amount of the EXIM Financing that may ultimately be made available to it, if any. The Company believes that the completion of the 2026 Elk Creek Study satisfies a key EXIM due diligence requirement reflected in the PPL, and the Company expects to advance to the next steps of the process relating to detailed engineering, procurement and construction contracting. The Company further believes that the 2026 Elk Creek Study, with its updated economic model, mineral resource and mineral reserve estimates and increased job creation projections, demonstrates that the Elk Creek Project satisfies the criteria for increased financing as contemplated by the PPL. The EXIM Financing remains subject to, among other matters, the satisfactory completion of EXIM’s due diligence, the completion of EXIM’s internal review and approval process, the negotiation and settlement of final terms, and the negotiation and execution of definitive documentation. Neither the letter of interest the Company received from EXIM in March 2023 nor the PPL represents a financing commitment from EXIM. Certain of these conditions, including the timing and sequencing of EXIM’s internal review and approval process, are outside the Company’s control, and the conditions to which any commitment would be subject are customary for financings of a similar nature by U.S. Government or other public lending institutions. The Company continues to meet with EXIM, to respond to requests for additional information from EXIM and from the consultants conducting due diligence on the Company’s application on behalf of EXIM, and to take steps to complete the additional project activities identified by the PPL. There can be no assurance as to what further project activities or matters EXIM may request in connection with the application process. Accordingly, the Company is currently unable to estimate the total amount of the EXIM Financing, if any, or how long the application process may take, and there can be no assurances that the Company will be able to successfully negotiate a final commitment of debt financing from EXIM, on acceptable terms, or at all. Other Government and Export Credit Support In addition to the EXIM Financing, the Company has pursued other government-supported sources of capital for the Elk Creek Project. For example, on August 4, 2025, ECRC entered into the DoW Agreement, a Project Sub-Agreement with Advanced Technology International, an entity acting on behalf of the Defense Industrial Base Consortium under the authority of the DoW, pursuant to which ECRC is entitled to receive up to an aggregate of approximately $10.0 million of reimbursement
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48 payments from the DoW upon the achievement of certain project milestones. The DoW Agreement has an initial term through December 30, 2028. As of June 30, 2026, approximately $8.1 million of such reimbursement payments had been received and approximately $1.9 million remained available upon the achievement of the remaining milestones. In addition, we are seeking other alternative sources of debt financing, which may include loans or loan guarantees from commercial or government-supported sources. The Company can provide no assurance as to the timing or outcome of any additional debt financing arrangements, or that any other loans or loan guarantees will ultimately be obtained. See Item 1A., "Risk Factors – Changes in geopolitical conditions and U.S. critical minerals policy could reduce the strategic importance of our planned products and adversely affect our business." In March 2015, the Company obtained in-principle eligibility approval for a loan guarantee to be provided by the Federal Republic of Germany under its untied loan guarantee program, which supports financing for projects that contribute to securing supplies of strategic raw materials in the economic interest of Germany. That approval was based on the Company’s offtake agreement with ThyssenKrupp Metallurgical Products GmbH for the purchase of approximately 50% of planned ferroniobium production from the Elk Creek Project, and constituted the first of the approvals required under the program. The Company received a reiteration of in-principle eligibility in 2017 following completion of the then-current feasibility study for the Elk Creek Project, and received a further reiteration of in-principle eligibility in June 2026. No subsequent approvals under the program have been obtained, and the amount of loan guarantees, if any, that may be made available has not been determined. Any such guarantee would be coordinated with the EXIM Financing and with any other debt financing obtained for the Elk Creek Project. The Company can provide no assurance as to the timing or outcome of any further review under the program, or that any loan guarantee will ultimately be provided. On May 16, 2025, UK Export Finance issued to the Company an expression of interest with respect to a potential debt guarantee of up to $200 million in support of the Elk Creek Project, which is non-binding and is conditioned upon, among other things, the execution of an offtake agreement for one or more of NioCorp’s planned products with UK-based companies that in turn can be shown to support UK exports. A debt guarantee issued by UK Export Finance, if any, would be coordinated with the EXIM Financing and with any loan guarantee provided under the German program described above. The DoW Agreement does not provide funding for the construction of the Elk Creek Project, and neither the UK Export Finance expression of interest nor the in-principle eligibility approval from the Federal Republic of Germany represent a financing commitment. Financing and Strategic Alternatives The Company remains open to financing and strategic opportunities that support its overall financing and development objectives for the Elk Creek Project, which may include the issuance of additional equity; corporate or project-level debt; government and export credit agency financing; offtake, prepayment, royalty or streaming arrangements; and joint venture, strategic investment or other strategic transactions. In evaluating any such opportunity, management intends to consider, among other factors, the total cost of capital, the certainty and timing of funding, the effect on the Company’s ability to construct and operate the Elk Creek Project on its anticipated schedule, and the value delivered to the Company’s shareholders. Capital Resources and Restrictions on Financing The Yorkville Equity Facility Financing Agreement expired by its terms on April 1, 2026, and, as of the date of this Annual Report on Form 10-K, the Company has not entered into a replacement equity facility. On October 10, 2025, the Company filed an automatic shelf registration statement on Form S-3ASR, which became effective upon filing and under which the Company may offer and sell securities from time to time. Except for the potential funding from the exercise of Options and Warrants and the reimbursement payments available to ECRC under the DoW Agreement, we currently have no further funding commitments or arrangements for additional financing as of the date of this Annual Report on Form 10-K. Pursuant to the Exchange Agreement, NioCorp is restricted from issuing equity or equity-linked securities (other than Common Shares) or any preferred equity or non-voting equity if such issuance would adversely impact the rights of the holders of the shares of Class B common stock of ECRC, without the consent of the holders of a majority of the shares of Class B common stock of ECRC. Notwithstanding the restrictions set forth in the Exchange Agreement, there can be no assurance that we will be able to secure additional financing on acceptable terms, or at all. The quantity of funds to be raised and the terms of any proposed equity or debt financing that may be undertaken will be negotiated by management as opportunities to raise funds arise. Management may pursue funding sources of both debt and equity financing, including but not limited to the issuance of equity securities in the form of Common Shares, Warrants, subscription receipts, or any combination thereof in units of the Company pursuant to private placements to accredited investors or pursuant to public offerings in the form of underwritten/brokered offerings, registered direct offerings, or other forms of equity financing and public or private issuances of debt securities, including secured and unsecured convertible debt instruments, or secured debt project financing.
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49 Management does not currently know the terms pursuant to which such financings may be completed in the future, but any such financings will be negotiated at arm’s-length. Future financings involving the issuance of equity securities or derivatives thereof may be completed at a discount to the then-current market price of the Company’s securities and would be dilutive to current shareholders. In addition, we could raise funds through the sale of interests in our mineral properties. However, we cannot provide any assurances that we will be able to be successful in raising such funds. Additional Capital Requirements As defined under S-K 1300, we are a development stage issuer, and we have incurred losses since our inception. The Company will require additional capital to construct the Elk Creek Project and to meet its long-term operating requirements. Based on its current liquidity position and planned expenditures, management believes the Company has sufficient resources to meet its obligations as they become due within one year from the issuance date of the consolidated financial statements included in this Annual Report on Form 10-K, which have been prepared on a going concern basis. Management expects that future capital requirements will be met through a combination of debt financing, equity financing and other funding sources. Uncertainty in capital markets, supply chain disruptions, increased interest rates and inflation, and the potential for regional recessions have contributed to general global economic uncertainty. During fiscal year 2026, these events continued to create uncertainty with respect to overall project funding and timelines. Cash Management and Credit Risk We have no exposure to any asset-backed commercial paper. Other than cash held by our subsidiaries for their immediate operating needs in Colorado and Nebraska, all of our cash reserves are on deposit with major U.S. and Canadian chartered banks. We do not believe that the credit, liquidity, or market risks with respect thereto have increased as a result of the current market conditions. However, in order to achieve greater security for the preservation of our capital, we have held our cash reserves in deposit accounts and other highly liquid instruments, which may result in lower rates of interest, and therefore lower interest income, than alternative investments. Operating Activities During the year ended June 30, 2026, the Company’s operating activities consumed $15.9 million of cash (2025: $10.7 million). Overall, operational outflows during fiscal year 2026 increased from fiscal year 2025 primarily due to increased exploration and general and administrative expenditures, offset by non-cash activity related to changes in valuation of earnout shares and warrant liabilities. Going forward, the Company’s working capital requirements are expected to increase substantially in connection with the development of the Elk Creek Project. Investing Activities During the year ended June 30, 2026, the Company's investing activities consumed $29.7 million of cash (2025: $0.0 million), which included the acquisition of additional land and mineral rights, certain Scandium alloy manufacturing assets, and construction expenditures for the Company's Portal Project. Financing Activities Net cash provided by financing activities was $437.1 million in fiscal year 2026 (2025: $34.2 million). This increase in financing inflows primarily reflects the timing of cash inflows from the financing transactions disclosed above under “Liquidity and Capital Resources—Overview.” Cash Flow Considerations The Company has historically relied upon debt and equity financing to finance its activities. Subject to the restrictions set forth in the Exchange Agreement, the Company may pursue additional debt and/or equity financing in the medium term; however, there can be no assurance the Company will be able to obtain any required financing in the future on acceptable terms.
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The Company has limited financial resources compared to its proposed expenditures, no source of operating income, and no assurance that additional funding will be available to it for current or future projects, although the Company has been successful in the past in financing its activities through the sale of equity securities. The ability of the Company to arrange additional financing in the future will depend, in part, on the prevailing capital market conditions, and its success in developing the Elk Creek Project. Any quoted market for the Common Shares may be subject to market trends generally, notwithstanding any potential success of the Company in creating revenue, cash flows, or earnings, and any depression of the trading price of the Common Shares could impact its ability to obtain equity financing on acceptable terms. Historically, the Company has used net proceeds from issuances of Common Shares to provide sufficient funds to meet its near-term exploration and development plans and other contractual obligations when due. However, development and construction of the Elk Creek Project will require substantial additional capital resources. This includes near-term funding and, ultimately, funding for Elk Creek Project construction and other costs. See “Liquidity and Capital Resources” above, for the Company’s discussion of arrangements related to possible future financings. Environmental Our mining and exploration activities are subject to various federal and state laws and regulations governing the protection of the environment. We have made, and expect to make in the future, expenditures to comply with such laws and regulations, but cannot predict the full amount of such future expenditures. As of June 30, 2026 and 2025, we had accrued $48 and $48, respectively, related to estimated environmental obligations. Forward-Looking Statements The foregoing discussion and analysis, as well as certain information contained elsewhere in this Annual Report on Form 10-K, contain “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act, and are intended to be covered by the safe harbor created thereby. See the discussion in “Forward-Looking Statements” in Item 1., “Business.” Accounting Developments For a discussion of Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements, see Note 3 to the consolidated financial statements included in this Annual Report on Form 10-K. Critical Accounting Estimates and Recent Accounting Pronouncements Our significant accounting policies are described in Note 3 to the Consolidated Financial Statements included in this Annual Report on Form 10-K. As described in Note 3, we are required to make estimates and assumptions that affect the reported amounts and related disclosures of assets, liabilities, revenue, and expenses. Our estimates are based on our experience and our interpretation of economic, political, regulatory, and other factors that affect our business prospects. Many of the inputs into our estimation process are subjective and are subject to uncertainty over time and therefore, actual results may differ significantly from our estimates. Note 3 also discloses recent accounting pronouncements applicable to the Company. We believe that our most critical accounting estimates are related to the carrying value of our long term assets, intangible assets and goodwill; accounting for income taxes and the valuation of deferred tax assets; and the valuation of liabilities associated with Warrants and Earnout Shares, as they require us to make assumptions that are highly uncertain at the time the accounting estimates are made and changes in them are reasonably likely to occur from period to period. Management has discussed the development and selection of these critical accounting estimates with the Audit Committee of our Board (the “Audit Committee”), and the Audit Committee has reviewed the disclosures presented below. In addition, there are other items within our financial statements that require estimation, but are not deemed to be critical. However, changes in estimates used in these and other items could have a material impact on our consolidated financial statements. Carrying Value of Long-Lived Assets, Intangible Assets, and Goodwill The recoverability of the carrying values of mineral properties is dependent upon economic reserves being discovered or developed on the properties, permitting, financing, start-up, and commercial production from, or the sale/lease of, or other strategic transactions related to these properties. Development and/or start-up of a project will depend on, among other things, management’s ability to raise sufficient capital for these purposes. We assess the carrying cost of our mineral properties for impairment whenever information or circumstances indicate the potential for impairment. Key inputs include events and circumstances such as our inability to obtain all the necessary permits, changes in the legal status of our mineral properties, government actions, the results of exploration activities and technical evaluations and changes in economic conditions, including the price of commodities or input prices. Many of these inputs are subjective and are subject to uncertainty over time. Such evaluations compare estimated future net cash flows with our carrying costs and future obligations on an undiscounted
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basis. If it is determined that the estimated future undiscounted cash flows are less than the carrying value of the property, an impairment loss will be recorded, measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Where estimates of future net cash flows are not determinable and where other conditions indicate the potential for impairment, management uses available market information and/or third-party valuation experts to assess if the carrying value can be recovered and to estimate fair value. Long-lived assets, other than mineral properties, held and used by the Company are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. For purposes of evaluating the recoverability of long-lived assets, the recoverability test is performed using undiscounted net cash flows related to the long-lived assets. If such assets are considered to be impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. The fair value of the acquired technology was estimated using the multi-period excess earnings method. Significant inputs include estimated future cash flows attributable to the acquired technology, an appropriate discount rate, and assumptions regarding technological obsolescence. The intangible asset is amortized on a straight-line basis over an estimated useful life of ten years and is reviewed for impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Assumptions used in the model are subjective and require significant judgment. Goodwill is assessed for impairment annually, or more frequently upon the occurrence of a triggering event. The Company operates as a single reporting unit, as our scandium commercialization activities are not managed or reviewed as a discrete component by the Chief Operating Decision Maker and no discrete financial information is prepared at that level. Accordingly, goodwill is tested at the consolidated reporting unit level. This determination will be reassessed as our scandium commercialization activities mature. Income Taxes We have assets, hold interests, and conduct activities in the U.S. and Canada and are subject to their tax regimes. Tax laws are complex and continue to evolve. While we have a history of losses, our assumptions made in tax returns are subject to review and interpretation by taxing authorities and could be modified. Management judgment is required in determining our provision for income taxes, our deferred tax assets and liabilities, and any valuation allowance recorded against our deferred tax assets. We consider factors such as the cumulative income or loss in recent years; reversal of deferred tax liabilities; projected future taxable income exclusive of temporary differences; the character of the income tax asset, including income tax positions; tax planning strategies and the period over which we expect the deferred tax assets to be recovered in the determination of the valuation allowance. In the event that actual results differ from these estimates or we adjust our estimates in the future, we may need to adjust our valuation allowance, which could materially impact our financial position and results of operations. Financial Instruments Carried at Fair Value The fair value of our Earnout Shares was determined using various significant unobservable inputs, including a discount rate and our best estimate of expected volatility and expected holding periods. The fair value of our private Warrants was determined using quoted prices or inputs that are observable, either directly or indirectly. Changes in the estimated fair values of these liabilities may have material impacts on our results of operations in any given period, as any increases in these liabilities have a corresponding negative impact on our U.S. GAAP results of operations. See Notes 8 and 9 to our consolidated financial statements included in this Annual Report on Form 10-K for additional details. Other The Company has one class of shares, being Common Shares. A summary of outstanding Common Shares, Vested Shares, Options, and Warrants as of September 25, 2026, is set out below, on a fully diluted basis. Common Shares Outstanding (fully diluted) Common Shares 145,849,630 Vested Shares of ECRC Class B common stock 3,516,140 Options 5,052,901 Warrants 18,696,530 (1) Each exchangeable into one Common Share at any time, and from time to time, until the tenth anniversary of the Closing Date. (2) Each exercisable for one Common Share. (3) Includes 15,666,526 NioCorp Assumed Warrants that are each exercisable for 1.11829212 Common Shares, and 3,041,254 Warrants that are each exercisable into one Common Share. (1) (2) (3)
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52 ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK Interest rate risk The Company’s exposure to changes in market interest rates, relates primarily to the Company’s earned interest income on cash deposits and short-term investments. The Company maintains a balance between the liquidity of cash assets and the interest rate return thereon. The carrying amount of financial assets, net of any provisions for losses, represents the Company’s maximum exposure to credit risk. Foreign currency exchange risk The Company incurs expenditures in both U.S. and Canadian dollars. Canadian dollar expenditures are primarily related to engineering and metallurgical expenses, as well as certain professional services. As a result, currency exchange fluctuations may impact the costs of our operating activities. To reduce this risk, we maintain sufficient cash balances in Canadian dollars to fund expected near- term expenditures. Commodity price risk The Company is exposed to commodity price risk related to the elements associated with the Elk Creek Project. A significant decrease in the global demand for these elements may have a material adverse effect on our business. The Elk Creek Project is not in production, and the Company does not currently hold any commodity derivative positions. ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA
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53 REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM To the shareholders and the Board of Directors of NioCorp Developments Ltd. Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of NioCorp Developments Ltd. and subsidiaries (the "Company") as of June 30, 2026 and 2025, the related consolidated statements of operations and comprehensive loss, cash flows, and shareholders' equity and redeemable noncontrolling interest, for each of the two years in the period ended June 30, 2026, the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of June 30, 2026 and 2025, and the results of its operations and its cash flows for each of the two years in the period ended June 30, 2026 in conformity with accounting principles generally accepted in the United States of America. Basis for Opinion These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion. Critical Audit Matter The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates. Carrying value of Mineral Properties and Long-Lived Assets – Refer to Notes 3(d) through 3(g) to the financial statements Critical Audit Matter Description As of June 30, 2026, the Company held mineral properties and long-lived assets (which includes property and equipment, intangible assets, and goodwill). The Company assesses mineral properties, property and equipment, and intangible assets for impairment whenever events or changes in circumstances indicate respective carrying amounts may not be recoverable. For goodwill, the Company assesses impairment at least annually, or more frequently upon the occurrence of a triggering event, to determine if it is more likely than not that the asset is impaired. The recoverability of the carrying values of mineral properties, property and equipment, and intangible assets, along with the impairment of goodwill, depends on the development of economic reserves, permitting, financing, start-up, and commercial production from the properties, amongst other factors.
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54 If impairment indicators are present when evaluating impairment of goodwill or recoverability of mineral properties, property and equipment, and intangible assets, the respective assets are tested for impairment. For mineral properties, property and equipment, and intangible assets, estimated undiscounted future net cash flows of the assets are compared to their respective carrying amounts, with an impairment loss recognized against the assets for any excess of the carrying amount over the respective estimated undiscounted future net cash flows. For goodwill, the fair value of the reporting unit is compared to the carrying value of the reporting unit, with an impairment loss recognized against goodwill for any excess of the carrying value of the reporting unit over fair value of the reporting unit, limited to the total amount of goodwill. Given the significant assumptions made by management in determining if events or changes indicated that the carrying amounts of the long-live assets were impaired during the current year, performing audit procedures to evaluate the reasonableness of management's conclusions required a high degree of auditor judgment and an increased extent of effort. How the Critical Audit Matter Was Addressed in the Audit Our audit procedures related to the recoverability of mineral properties and long-lived assets, including impairment of goodwill, consisted of risk assessment and testing management’s impairments analyses through the following, among other procedures: • We evaluated management’s assessment of recoverability of mineral properties, property and equipment, and intangible assets through the following procedures: o We evaluated the reasonableness of management’s assessment over ASC 360, Property, Plant, and Equipment, qualitative impairment indicators regarding recoverability of the carrying amounts of the assets. o We performed a qualitative assessment as of June 30th to evaluate whether events or changes in circumstances indicated that the carrying amounts of the assets may not be recoverable, considering information in industry reports and the Company’s future business strategies. o Tested the design and implementation of management’s controls over the recoverability of mineral properties, property and equipment, and intangible assets. • We evaluated management’s assessment of impairment of goodwill through the following procedures: o We evaluated the reasonableness of management’s annual assessment over ASC 350, Intangibles – Goodwill and Other, qualitative impairment indicators regarding whether it is more likely than not that the carrying amount of the associated reporting unit, including goodwill, exceeds the fair value of the reporting unit as of the Company’s annual assessment date of April 1st. o We performed a qualitative assessment as of June 30th to evaluate potential impairment indicators during the period from management’s April 1st annual goodwill impairment assessment date to the June 30th balance sheet date, considering information in industry reports and the Company’s future business strategies. o Tested the design and implementation of management’s controls over the impairment of goodwill. • Evaluated the completeness and accuracy of the disclosures related to the recoverability of the mineral properties and long-lived assets, including impairment of goodwill. /s/ DELOITTE & TOUCHE LLP Denver, Colorado September 25, 2026 We have served as the Company's auditor since fiscal year 2024.
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The accompanying notes are an integral part of these consolidated financial statements 55 NioCorp Developments Ltd. Consolidated Balance Sheets (expressed in thousands of U.S. dollars, except share data) As of June 30, 2026 2025 ASSETS Current Cash and cash equivalents $ 415,004 $ 25,554 Restricted cash 2,102 — Prepaid expenses and other 1,740 1,183 Total current assets 418,846 26,737 Non-current Right-of-use assets 91 118 Property and equipment, net 11,569 839 Mineral properties 25,726 16,085 Intangible assets, net 5,672 — Goodwill 2,220 — Other assets 2,776 40 Total assets $ 466,900 $ 43,819 LIABILITIES Current Accounts payable and accrued liabilities $ 5,638 $ 1,795 Deferred reimbursements 6,177 — Warrant liabilities, at fair value 4,606 — Operating lease liability 94 98 Total current liabilities 16,515 1,893 Non-current Warrant liabilities, at fair value 6,140 6,852 Earnout liability, at fair value 14,451 5,880 Operating lease liability — 33 Total liabilities 37,106 14,658 Commitments and contingencies (Note 3r, 6) Redeemable noncontrolling interest (1,446) 838 SHAREHOLDERS' EQUITY Common stock, no par value, unlimited shares authorized; 145,838,380 and 58,491,196 shares outstanding, respectively 660,049 208,551 Accumulated deficit (227,872) (179,317) Accumulated other comprehensive loss (937) (911) Total shareholders’ equity 431,240 28,323 Total liabilities, redeemable noncontrolling interest, and shareholders’ equity $ 466,900 $ 43,819
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The accompanying notes are an integral part of these consolidated financial statements 56 NioCorp Developments Ltd. Consolidated Statements of Operations and Comprehensive Loss (expressed in thousands of U.S. dollars, except share and per share data) For the year ended June 30, 2026 2025 Operating expenses Exploration expenditures $ 16,076 $ 4,135 General and administrative expenditures 22,233 7,823 Total operating expenses 38,309 11,958 Change in fair value of earnout shares liability 8,571 2,063 Change in fair value of warrant liabilities 13,034 4,093 Change in fair value of convertible notes — 40 Interest expense — 48 Interest income (9,146) (94) Other non-operating expense (income) 13 (126) Loss before income taxes (50,781) (17,982) Income tax benefit — — Net loss (50,781) (17,982) Less: Net loss attributable to redeemable noncontrolling interest (2,226) (577) Net loss attributable to the Company $ (48,555) $ (17,405) Reporting currency translation (26) — Total comprehensive loss (50,807) (17,982) Less: Comprehensive loss attributable to redeemable noncontrolling interest (2,226) (577) Comprehensive loss attributable to the Company $ (48,581) $ (17,405) Loss per common share, basic and diluted $ (0.41) $ (0.36) Weighted Average Shares Outstanding 117,214,449 45,072,895
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The accompanying notes are an integral part of these consolidated financial statements 57 NioCorp Developments Ltd. Consolidated Statements of Cash Flows (expressed in thousands of U.S. dollars) For the year ended June 30, 2026 2025 CASH FLOWS FROM OPERATING ACTIVITIES Net loss for the period $ (50,781) $ (17,982) Adjustments for: Change in valuation of earnout shares liability 8,571 2,063 Change in valuation of warrant liabilities 13,034 4,093 Change in fair value of convertible note — 40 Accretion of convertible debt — 43 Share-based compensation 4,441 789 Loss on equity facility issuances 724 589 Fair value of insider warrants — 144 Depreciation 359 3 Unrealized (gain) loss on equity securities (1) 1 Noncash lease activity (10) (6) Other gains — (122) (23,663) (10,345) Change in working capital items: Prepaid expenses and other (459) (267) Deposits (44) (2) Deferred reimbursements 6,177 — Accounts payable and accrued liabilities 2,091 (48) Net cash used in operating activities (15,898) (10,662) CASH FLOWS FROM INVESTING ACTIVITIES Assets acquired in business combination (8,400) 0 Capitalized expenditures (21,257) (5) Net cash used in investing activities (29,657) (5) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from issuance of capital stock 467,202 45,666 Issuance of debt, net of costs — — Related party debt draws — 504 Related party debt repayments — (504) Debt repayments — (7,223) Share issue costs (30,069) (4,234) Net cash provided by financing activities 437,133 34,209 Exchange rate effect on cash and cash equivalents (26) — Change in cash and cash equivalents and restricted cash during period 391,552 23,542 Cash and cash equivalents and restricted cash, beginning of period 25,554 2,012 Cash and cash equivalents and restricted cash, end of period $ 417,106 $ 25,554 Supplemental cash flow information: Amounts paid for interest $ — $ 4 Non-cash investing and financing transactions: Conversion of debt for common shares — $ 501 Additions to construction in progress not yet paid 1,753 — Value of warrants issued — 2,262 Reclassification of warrant liabilities to equity 9,141 820
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The accompanying notes are an integral part of these consolidated financial statements 58 NioCorp Developments Ltd. Consolidated Statements of Shareholders’ Equity and Redeemable Noncontrolling Interest (expressed in thousands of U.S. dollars, except share data) CommonSharesOutstanding CommonStock AccumulatedDeficit AccumulatedOtherComprehensiveLoss TotalShareholders' Equity RedeemableNoncontrollingInterest Balance, June 30, 2024 38,062,647 $ 163,823 $ (161,912) $ (911) $ 1,000 $ 1,534 Equity placements 13,321,628 30,059 — — 30,059 — Yorkville equity facility draws 5,671,742 12,941 — — 12,941 — Warrant exercises 828,235 1,809 — — 1,809 — Option exercises 512 — — — — — Redemption of vested shares 348,085 119 — — 119 (119) Debt conversions 258,347 501 — — 501 — Issuance of Lind Consent warrants — 2,262 — — 2,262 — Conversion of private warrants — 482 — — 482 — Share-based compensation — 789 — — 789 — Share issuance costs — (4,234) — — (4,234) — Loss for the year — — (17,405) — (17,405) (577) Balance, June 30, 2025 58,491,196 $ 208,551 $ (179,317) $ (911) $ 28,323 $ 838 Equity placements 58,406,915 405,195 — — 405,195 — Yorkville equity facility draws 5,727,662 39,434 — — 39,434 — Warrant exercises 22,308,264 28,557 — — 28,557 — Option exercises 486,452 1,381 — — 1,381 — Redemption of vested shares 417,891 58 — — 58 (58) Conversion of private warrants — 2,501 — — 2,501 — Share-based compensation — 4,441 — — 4,441 — Share issuance costs — (30,069) — — (30,069) — Change in accumulated other comprehensive income — — — (26) (26) Loss for the year — (48,555) — (48,555) (2,226) Balance, June 30, 2026 145,838,380 $ 660,049 $ (227,872) $ (937) $ 431,240 $ (1,446)
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59 NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 1. DESCRIPTION OF BUSINESS NioCorp Developments Ltd. (the “Company” or “NioCorp”) was incorporated on February 27, 1987, under the laws of the Province of British Columbia and currently operates in one reportable operating segment consisting of exploration and development of mineral deposits in the United States, specifically, the Elk Creek Niobium/Scandium/Titanium property (the “Elk Creek Project”) located in southeastern Nebraska. On March 17, 2023 (the “Closing Date”), the Company closed a series of transactions pursuant to the Business Combination Agreement, dated September 25, 2022 (the “Business Combination Agreement”), among the Company, GX Acquisition Corp. II (“GXII”), and Big Red Merger Sub Ltd. (the closing of such transactions, the “Closing”). The Company currently earns no operating revenues and will require additional capital in order to advance the Elk Creek Project to construction and commercial operation. Liquidity As of June 30, 2026, the Company had cash and cash equivalents of $415,004 and working capital of $402,331. Based on its current liquidity position and planned expenditures, management believes the Company has sufficient resources to meet its obligations as they become due within one year from the issuance date of these consolidated financial statements, which have been prepared on a going concern basis. The Company will require additional capital to fully develop, construct, and operate the Elk Creek Project. Management expects that future capital requirements will be met through a combination of debt financing, equity financings, and other funding sources. 2. BASIS OF PREPARATION a) Basis of Preparation and Consolidation These consolidated financial statements have been prepared in conformity with generally accepted accounting principles of the United States of America (“U.S. GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission. The consolidated financial statements include the consolidated accounts of the Company and its wholly owned subsidiaries with all significant intercompany transactions eliminated. Certain transactions include reference to Canadian dollars (“C$”) where applicable. Certain reclassifications were made to the prior year's consolidated statement of operations and comprehensive loss to conform to the current year's presentation, combining professional fees, employee-related costs, and other operating expenses into a single line item, general and administrative expenditures. These consolidated financial statements include the accounts of the Company and the subsidiaries listed in the following table. All intercompany transactions and balances have been eliminated. Ownership at June 30, Subsidiary Jurisdiction of incorporation 2026 2025 0896800 B.C. Ltd. (“0896800”) British Columbia, Canada 100% 100% Elk Creek Resources Corp. (“ECRC”) (1) Delaware, USA 81.33% 80.42% NioCorp Advanced Metals and Alloys, LLC (“NAMA”) Delaware, USA 100% — NioCorp Technologies Limited United Kingdom 100% 100% (1) Represents 100% of Class A common stock owned by 0896800, and 3,516,140 and 3,934,031 Vested Shares and 3,391,596 and 3,391,596 Earnout Shares (each as defined below) held by third parties, and outstanding as of June 30, 2026 and 2025, respectively. b) Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of expenses during the reporting period. The Company regularly evaluates estimates and assumptions related to the
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 60 valuation of property and equipment, mineral properties, intangible assets, goodwill, deferred income tax asset valuations, earnout and warrant liabilities, and share-based compensation. The Company bases its estimates and assumptions on current facts, historical experience, and various other factors that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the other sources. The actual results experienced by the Company may differ materially and adversely from the Company’s estimates. To the extent there are material differences between estimates and the actual results, future results of operations will be affected. 3. SIGNIFICANT ACCOUNTING POLICIES a) Development Stage Issuer The Company is considered to be a development stage issuer under Subpart 1300 of Regulation S-K of the United States Securities Act of 1933, as amended (“S-K 1300”), and it devotes substantially all of its efforts to acquiring and exploring mining interests that management believes should eventually provide sufficient net profits to sustain the Company’s existence. Until such interests are engaged in commercial production, the Company will continue to seek additional funding to support the completion of its exploration and development activities. The Company’s activities are subject to significant risks and uncertainties, including its ability to secure sufficient funding to continue operations, to obtain proven and probable reserves, to comply with industry regulations and obtain permits necessary for development of the Elk Creek Project, as well as environmental risks and market conditions. b) Cash and Cash Equivalents Cash and cash equivalents include cash on hand, cash in banks, investments in certificates of deposit with original maturities of 90 days or less, and money market funds. The Company maintains the majority of its cash balances with two financial institutions. Accounts at banks in the United States (“U.S.”) are insured by the Federal Deposit Insurance Corporation (“FDIC”) up to $250, while accounts at banks in Canada are insured by the Canada Deposit Insurance Corporation (“CDIC”) up to C$100. At June 30, 2026, the Company had $413,932 and $129 in excess of the FDIC and CDIC insured limits, respectively. As of June 30, 2026, total cash, cash equivalents, and restricted cash was $417,106, consisting of cash and cash equivalents of $415,004 and restricted cash of $2,102. As of June 30, 2025, there was no restricted cash, and the total of $25,554 consisted entirely of cash and cash equivalents. Restricted cash consists primarily of funds held in escrow pursuant to an agreement with Johnson County, Nebraska for road improvements adjacent to the Elk Creek Project site. c) Foreign Currency Translation Functional and reporting currency Items included in the financial statements of each of the Company’s entities are measured using the currency of the primary economic environment in which the entity operates (“the functional currency”). The functional currency for all entities is the U.S. Dollar except for NioCorp Technologies Limited, which is measured in British Pounds. The reporting currency for these consolidated financial statements is U.S. dollars. Transactions in foreign currency Transactions made in a currency other than the functional currency are remeasured to the functional currency at exchange rates at the dates of the transactions. Monetary assets and liabilities denominated in foreign currencies at the reporting date are remeasured to the functional currency at the exchange rate at that date and non-monetary assets and liabilities are remeasured at historical rates. Foreign currency translation gains and losses are included in profit or loss.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 61 Translation to reporting currency Translation gains and losses from the application of the U.S. dollar as the reporting currency, if any, are included as part of cumulative currency translation adjustment, which is reported as a component of shareholders’ equity under accumulated other comprehensive loss. d) Mineral Properties Mineral property acquisition costs, including indirectly related acquisition costs, are capitalized when incurred. Acquisition costs include cash consideration and the fair market value of common shares, no par value, of the Company (“Common Shares”) issued as consideration. Properties acquired under option agreements, whereby payments are made at the sole discretion of the Company, are capitalized as mineral property acquisition costs at such time as the payments are made. Exploration costs are expensed as incurred. When it is determined that a mining deposit can be economically and legally extracted or produced based on established proven and probable reserves under S-K 1300, and the Company’s board of directors (the “Board”) has approved the commencement of formal development activities, development costs related to such reserves and incurred after such board approval will be considered for capitalization. The establishment of proven and probable reserves is based on results of feasibility studies, which indicate whether a property is economically feasible. Upon commencement of commercial production, capitalized costs will be amortized over their estimated useful lives or units of production, whichever is a more reliable measure. Capitalized amounts relating to a property that is abandoned or otherwise considered uneconomic for the foreseeable future are written off. Direct costs incurred in connection with the construction of the Elk Creek Project mine portal, including construction contractor costs and directly attributable construction management costs, are capitalized as construction in progress ("CIP") within property and equipment. CIP assets are not depreciated or amortized during the construction period. Upon substantial completion, accumulated CIP costs will be transferred to mine development assets and amortized using the units-of-production method over proven and probable reserves upon commencement of commercial production. The recoverability of the carrying values of mineral properties is dependent upon economic reserves being discovered or developed on the properties, permitting, financing, start-up, and commercial production from, or the sale/lease of, or other strategic transactions related to these properties. Development and/or start-up of a project will depend on, among other things, management’s ability to raise sufficient capital for these purposes. We assess the carrying cost of our mineral properties for impairment whenever information or circumstances indicate the potential for impairment. This would include events and circumstances such as our inability to obtain all the necessary permits, changes in the legal status of our mineral properties, government actions, the results of exploration activities and technical evaluations and changes in economic conditions, including the price of commodities or input prices. Such evaluations compare estimated future net cash flows with our carrying costs and future obligations on an undiscounted basis. If it is determined that the estimated future undiscounted cash flows are less than the carrying value of the property, an impairment loss will be recorded. Where estimates of future net cash flows are not determinable and where other conditions indicate the potential for impairment, management uses available market information and/or third-party valuation experts to assess if the carrying value can be recovered and to estimate fair value. There was no impairment recorded to mineral properties as of June 30, 2026 or 2025, respectively. e) Long Lived Assets Long-lived assets, other than mineral properties, held and used by the Company are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. For purposes of evaluating the recoverability of long-lived assets, the recoverability test is performed using undiscounted net cash flows related to the long-lived assets. If such assets are considered to be impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. There was no impairment recorded to long-lived assets as of June 30, 2026 or 2025, respectively. f) Intangible Assets The fair value of the acquired technology was estimated using the multi-period excess earnings method. Significant inputs include estimated future cash flows attributable to the acquired technology, an appropriate
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 62 discount rate, and assumptions regarding technological obsolescence. The intangible asset is amortized on a straight-line basis over an estimated useful life of ten years and is reviewed for impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Assumptions used in the model are subjective and require significant judgment. There was no impairment recorded to intangible assets as of June 30, 2026 or 2025, respectively. g) Goodwill Goodwill is assessed for impairment annually on April 1, or more frequently upon the occurrence of a triggering event. The Company operates as a single reporting unit, as our scandium commercialization activities are not managed or reviewed as a discrete component by the CODM (as defined below) and no discrete financial information is prepared at that level. Accordingly, goodwill is tested at the consolidated reporting unit level. This determination will be reassessed as our scandium commercialization activities mature. There was no impairment recorded to goodwill as of June 30, 2026 or 2025, respectively. h) Leases Under Accounting Standards Codification (“ASC”) 842, Leases, we determine if a contractual arrangement is, or contains, a lease at the inception date. Right-of-use ("ROU") assets and liabilities related to operating leases are separately reported in the consolidated balance sheets. The Company currently has no finance leases. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of the future lease payments over the lease term. When the rate implicit to the lease cannot be readily determined, we utilize our incremental borrowing rate in determining the present value of the future lease payments. The incremental borrowing rate is derived from information available at the lease commencement date and represents the rate of interest that a lessee would have to pay to borrow an amount equal to the lease payments on a collateralized basis over a similar term in a similar economic environment. Operating lease ROU assets also include any cumulative prepaid or accrued rent when the lease payments are uneven throughout the lease term. The ROU assets and lease liabilities may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease liabilities are increased by interest and reduced by payments each period, and the ROU asset is amortized over the lease term. For operating leases, interest on the lease liability and the amortization of the ROU asset result in straight-line rent expense over the lease term. Variable lease expenses are recorded when incurred. i) Warrants We apply relevant accounting guidance for warrants to purchase our Common Shares (“Warrants”) based on the nature of the relationship with the counterparty. The Company has made an accounting policy election that the “greater of” Share-Price Input to the Black-Scholes Value would not preclude equity classification. The Company has not had any historical transactions that include the “greater of” Share-Price Input feature. For Warrants issued to investors or lenders in exchange for cash or other financial assets, we follow guidance issued within ASC 480, Distinguishing Liabilities from Equity, and ASC 815, to assist in the determination of whether the Warrants should be classified as liabilities or equity. The fair value of Warrants is estimated using Black Scholes modeling or Monte Carlo modeling, depending on the settlement features embedded in the Warrant. Inputs under both models include inputs such as NioCorp’s Common Share price, the risk-free interest rate, the expected term, the volatility, and the dividend rate. Warrants that are determined to require liability classifications are measured at fair value upon issuance and are subsequently remeasured to their then fair value at each subsequent reporting period with changes in fair value recorded in current earnings. Warrants that are determined to require equity classifications are measured at fair value upon issuance and are not subsequently remeasured unless they are required to be reclassified. j) Earnout Shares Earnout Shares are classified as a liability due to failure to meet the equity classification criteria under ASC 815-40. The Earnout Shares are measured at fair value upon issuance and subsequently remeasured at each reporting period using a Monte Carlo simulation methodology, which includes inputs such as NioCorp’s Common Share price, the risk-free interest rate, the expected term, the weighted average of historical Common Share volatility and implied volatility underlying the Company’s publicly traded Warrants, the dividend rate, the conversion price,
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 63 and the number of Earnout Shares outstanding. Assumptions used in the model are subjective and require significant judgment. k) Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, receivables, equity securities, and accounts payable and accrued liabilities. It is management’s opinion that the Company is not exposed to significant interest, currency or credit risks arising from its financial instruments. The fair values of these instruments approximate their carrying value unless otherwise noted. l) Concentration of Credit Risk The financial instrument which potentially subjects the Company to credit risk is cash and cash equivalents. The Company holds investments or maintains available cash primarily in two commercial banks located in Vancouver, British Columbia and Columbus, Ohio. As part of its cash management process, the Company regularly monitors the relative credit standing of these institutions. m) Asset Retirement Obligation The Company is subject to various government laws and regulations relating to environmental disturbances caused by exploration and evaluation activities. The estimated costs associated with environmental remediation obligations are accrued in the period in which the liability is incurred if it is reasonably estimable or known. Until such time that a project life is established, the Company records the corresponding cost as an exploration stage expense and has accrued $48 for estimated obligations as of both June 30, 2026 and June 30, 2025. Future reclamation and environmental-related expenditures are difficult to estimate in many circumstances due to the early- stage nature of the Elk Creek Project, the uncertainties associated with defining the nature and extent of environmental disturbance, the application of laws and regulations by regulatory authorities and changes in reclamation or remediation technology. The Company periodically reviews accrued liabilities for such reclamation and remediation costs as evidence indicating that the liabilities have potentially changed becomes available. Changes in estimates are reflected in the consolidated statement of operations and comprehensive loss in the period an estimate is revised. n) Income Taxes Income taxes are provided based upon the liability method of accounting pursuant to ASC 740-10-25, “Income Taxes – Recognition.” Under the approach, deferred income taxes are recorded to reflect the tax consequences in future years of differences between the tax basis of assets and liabilities and their financial reporting amounts at each year-end. A valuation allowance is recorded against deferred tax assets if management does not believe the Company has met the “more likely than not” standard imposed by ASC 740-10-25-5 to allow recognition of such an asset. ASC 740-10-50, “Income Taxes – Disclosure,” requires the Company to evaluate its income tax positions and recognize a liability for uncertain tax positions that are not more likely than not to be sustained by tax authorities. As of June 30, 2026 and 2025, the Company believes it had no income tax uncertainties that required recognition of a liability. If the Company were to determine that uncertain tax positions meet the criteria for recognition, an estimated liability and related interest and penalties would be recognized as income tax expense. o) Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest refers to non-controlling interest associated with the Vested Shares that are redeemable upon the occurrence of an event that is not solely within the Company’s control and is reported in the mezzanine section between total liabilities and shareholders’ equity, as temporary equity in the Company’s consolidated balance sheets. The Company’s non-controlling interest is redeemable at fair value, and no adjustment to the earnings per share numerator is required because redemption at fair value is not considered an economic distribution different from other common stockholders. p) Basic and Diluted Per Share Disclosure Basic earnings (loss) per share represents net earnings (loss) attributable to common shareholders divided by the weighted average number of Common Shares outstanding during the period. The Company considers Vested
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) Shares and Released Earnout Shares (each as defined in Note 8), to be participating securities, requiring the use of the two-class method. Diluted earnings (loss) per share represents net earnings (loss) attributable to common shareholders divided by the weighted average number of Common Shares outstanding, inclusive of the dilutive impact of all potentially dilutive securities outstanding during the period, as applicable. The Company utilizes the weighted average method to determine the impact of changes in a participating security on the calculation of loss per share. The following table sets forth the computation of the Company’s basic and diluted net loss per share attributable to common shareholders: For the year ended June 30, 2026 2025 Net loss $ (50,781) $ (17,982) Adjust: Net loss attributable to noncontrolling interest (2,226) (577) Net loss available to participating securities (48,555) (17,405) Net loss attributable to Vested Shares (875) (1,102) Net loss attributed to common shareholders - basic and diluted $ (47,680) $ (16,303) Denominator: Weighted average shares outstanding – basic and diluted 117,214,449 45,072,895 Loss per Common Share outstanding – basic and diluted $ (0.41) $ (0.36) The following shares underlying options to purchase Common Shares (“Options”) and Warrants were antidilutive due to a net loss in the periods presented and, therefore, were excluded from the dilutive securities computation for the periods indicated below: For the year ended June 30, Excluded potentially dilutive securities : 2026 2025 Options 4,147,500 3,020,000 Warrants 20,561,006 31,839,152 Total potentially dilutive securities 24,708,506 34,859,152 (1) The number of shares is based on the maximum number of shares issuable on exercise or conversion of the related securities as of the period end. Such amounts have not been adjusted for the treasury stock method or weighted average outstanding calculations as required if the securities were dilutive. (2) Earnout Shares (as defined below) are excluded as the vesting terms were not met as of the end of the reporting period. q) Share Based Compensation The Company grants Options to directors, officers, employees, and business advisors. Option terms and vesting conditions are at the discretion of the Board. The Option exercise price is equal to the closing market price on the Nasdaq Stock Market LLC (“Nasdaq”) on the day preceding the date of the grant. The Company estimates the fair value of Options using the Black-Scholes option pricing model. The Company recognizes forfeitures as they occur. r) Retirement Plan The Company sponsors a 401(k) savings plan covering substantially all eligible employees. Beginning January 1, 2026, the Company began matching participant contributions equal to 100% of the participant's contributions up to 4% of eligible compensation, with such matching contributions vesting immediately. The Company recognized $35 of expense for matching contributions for the year ended June 30, 2026. There is no comparable (1)(2)
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 65 amount for the prior year, as the Company's matching contribution program was not in effect prior to January 1, 2026. s) Recent Accounting Standards Recently Adopted Accounting Standards In December 2025, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities. The guidance establishes authoritative accounting and disclosure requirements for government grants received by business entities, permits early adoption, and is effective for annual reporting periods beginning after December 15, 2028, with application on a prospective basis. The Company early adopted ASU 2025-10 effective July 1, 2025. Upon adoption, the Company concluded that the DoW Agreement (as defined in Note 11 below) represents a government grant within the scope of Topic 832. Adoption of the guidance did not have a material impact on the Company’s consolidated financial statements, as the Company’s existing accounting policies for accounting for such grants are consistent with the guidance. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures (Topic 740), which establishes new income tax disclosure requirements in addition to modifying and eliminating certain existing ones. The new guidance requires consistent categorization and greater disaggregation of information in the income tax rate reconciliation, as well as further disaggregation of income taxes paid. We adopted ASU 2023-09 for the year ended June 30, 2026, and applied the guidance retrospectively for all periods presented in the notes to the consolidated financial statements. The adoption did not have a material impact on our consolidated financial statements for the year ended June 30, 2026, but did require additional disclosures. Issued and Not Effective In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income -Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. ASU 2024-03 requires the disclosure of additional information related to certain costs and expenses, including amounts of inventory purchases, employee compensation, and depreciation and amortization included in each income statement line item. This ASU also requires disclosure of the total amount of selling expenses and our definition of selling expenses. This ASU is effective for our annual report for the period ending June 30, 2028, and for interim period reports beginning thereafter on a prospective or retrospective basis. Early adoption is permitted. We are currently evaluating the impact of adopting this ASU on our consolidated financial statements and disclosures. From time to time, new accounting pronouncements are issued by the FASB that are adopted by the Company as of the specified effective date. Unless otherwise discussed, recently issued accounting pronouncements are not expected to have a material impact on the Company's consolidated financial statements. 4. ACQUISITION On December 4, 2025, the Company completed the acquisition of certain manufacturing assets and intellectual property of FEA Materials LLC, a producer of scandium-containing aluminum master alloys. The Company did not acquire any equity or other legal interest in FEA Materials LLC in connection with the transaction. The transaction was accounted for as a business combination under ASC 805 as the acquired assets and processes constituted a business. The acquisition was made to obtain proprietary technology and manufacturing capabilities to support the Company’s scandium alloy commercialization strategy, and control was obtained through the purchase of the acquired assets. The following table summarizes the fair values of the assets acquired at the acquisition date: Fair Value Accounts receivable and prepaids $ 7 Inventory 88 Fixed assets 63 Security deposit 5 Intangible asset – technology 6,017
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 66 Goodwill 2,220 Assets acquired $ 8,400 The excess of the purchase consideration over the fair value of net assets acquired, totaling $2,220, was recorded as goodwill. The goodwill primarily reflects expected future growth opportunities and anticipated synergies resulting from the integration of the acquired technology and production capabilities into the Company’s scandium alloy commercialization strategy. The goodwill is expected to be deductible for income tax purposes. The purchase price allocation is based on management’s estimates as of the acquisition date, and management has completed its evaluation of the fair values of the assets acquired. The Company recognized identifiable intangible assets related to acquired technology, consisting of a group of patented and proprietary intellectual property. The intangible assets were valued using an income approach, specifically the multi-period excess earnings method, which incorporates significant unobservable inputs (Level 3), including management’s estimates of future cash flows, discount rates, and assumptions related to obsolescence. The acquired intangible assets are being amortized on a straight-line basis over their estimated weighted-average remaining useful life of 10 years. The Company has recognized $345 of amortization expense through June 30, 2026, and expects to recognize amortization expense of approximately $602 annually for each of fiscal years 2027 through 2031, with the remaining $2,662 recognized thereafter. The Company incurred $131 of transaction costs related to the acquisition, which were expensed as incurred and recognized in other operating expenses. Pro forma financial information has not been presented as the acquisition was not deemed significant under Securities and Exchange Commission Regulation S-X. 5. PROPERTY AND EQUIPMENT, NET As of June 30, 2026 2025 Construction in progress $ 5,651 $ — Fixed assets and vehicles 204 46 Total depreciable assets 5,855 46 Accumulated depreciation (24) (14) Net depreciable assets 5,831 32 Land 5,738 807 Property and equipment, net $ 11,569 $ 839 Property Acquisitions In connection with the development of the Elk Creek Project, ECRC, an indirect majority-owned subsidiary of the Company, acquired additional land and associated mineral rights in Johnson County, Nebraska, as described below. August Property Purchases On August 1, 2025, ECRC closed its options to purchase three parcels of land consisting of (i) an 80-acre parcel of surface rights and (ii) two smaller parcels totaling approximately 1.66 acres that included both surface rights and associated mineral rights. The total purchase price was approximately $2,699, including $35 of indirect costs. Of this amount, $2,650 was allocated to land and $49 was allocated to mineral properties. September Property Purchases On September 30, 2025, ECRC closed on its options to purchase two additional parcels of land consisting of (i) a 105.77-acre parcel and (ii) a 220-acre parcel, each including both surface rights and associated mineral rights (the "September Property Purchases"). The total purchase price was approximately $11,325, including $29 of indirect costs. Of this amount, $2,263 was allocated to land and $9,062 was allocated to mineral properties.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 67 November Property Purchase On November 7, 2025, ECRC acquired a 40-acre parcel of land and associated mineral rights located within the one-square-mile section that comprises the Elk Creek Project area. The acquisition was completed through (i) the transfer of surface rights to a separate 40-acre tract previously acquired as part of the September Property Purchases, (ii) cash consideration of $500 for the mineral rights, and (iii) the grant of a 2% net smelter return ("NSR") royalty on the acquired parcel. The surface-rights exchange involved parcels of substantially identical value, resulting in no gain or loss recognized. The total purchase price was $551, including $51 of indirect costs, with $531 allocated to mineral properties and $20 allocated to land. Construction in Progress Construction in progress consists of costs incurred for the development of the mine portal and related infrastructure at the Elk Creek Project. 6. MINERAL PROPERTIES Mineral properties consist of original acquisition costs and purchased mineral rights related to the Elk Creek Project, as discussed in Note 5. The Company currently owns approximately 550 acres of land and associated mineral rights, an additional 80 acres of mineral rights, and an additional 80 acres of surface rights. The mineral rights include a 2% NSR royalty. In addition to the land and mineral rights currently owned by the Company, the property interests of Elk Creek include six mineral exploration option-to-purchase agreements which include a pre-determined buyout for permanent ownership of the mineral and/or surface rights. Terms of the agreements require no further significant payments, and the Company may terminate the leases, negotiate lease extensions, or elect to purchase the mineral and/or surface rights any time. Agreements that allow for the purchase of mineral rights contain provisions whereby the landowners would retain a 2% NSR royalty. During the year ended June 30, 2025, the Company completed negotiations with landowners in Nebraska and entered into contract amendments which extended the option periods by approximately five years for option to purchase agreements (“OTP”) covering six parcels of land for project construction and operation which the Company does not already own. The Company recorded an exploration expense in the year ended June 30, 2025, for $310 for OTP extension payments made. 7. ACCOUNTS PAYABLE AND ACCRUED LIABILITIES As of June 30, 2026 2025 Accounts payable, trade $997 $692 Trade payable accruals 2,557 1,055 Employee salary, benefit, and bonus accruals 2,036 — Environmental accruals 48 48 Total accounts payable and accrued liabilities $5,638 $1,795 8. CLASS B COMMON STOCK OF ECRC Holders of the Class B common stock of ECRC have the right to exchange such shares for Common Shares on a one-for-one basis, subject to certain equitable adjustments, under certain conditions. Of the issued and outstanding shares of Class B common stock of ECRC, 4,565,808 shares (the “Vested Shares”) were vested as of the Closing Date and are exchangeable at any time, and from time to time, until the tenth anniversary of the Closing Date (the “Ten-Year Anniversary”) and 3,391,596 shares (the “Earnout Shares”) are exchangeable until the Ten-Year Anniversary, subject to certain vesting conditions. Under certain circumstances, and subject to certain exceptions, NioCorp may instead settle all or a portion of any exchange pursuant to the terms of the Exchange Agreement, dated as of March 17, 2023, by and among NioCorp, ECRC, and GX Sponsor II LLC (the “Sponsor”) in cash, in lieu of Common Shares, based on a volume-weighted average price of Common Shares. During the years ended June 30, 2026 and 2025, 417,891 and 348,085 Vested Shares, respectively, were exchanged for an equivalent number of Common Shares, and as of June 30, 2026, 3,516,140 Vested Shares remain outstanding. These
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 68 exchanges resulted in a change in the Company’s ownership interest in ECRC and were accounted for as an equity transaction in accordance with ASC 810-10-45-23, with no gain or loss recognized. Accordingly, the carrying amount of the noncontrolling interest was adjusted to reflect the change in the Company’s ownership interest with a corresponding offset to equity. Both Vested Shares and Released Earnout Shares (as defined below) may be exchanged by the holders into Common Shares at any time. All Vested Shares and Earnout Shares must be exchanged for Common Shares by the Ten-Year Anniversary except for Released Earnout Shares that have been vested for a period of fewer than twenty-four months as of the Ten-Year Anniversary. Such Released Earnout Shares will be forfeited if not exchanged for Common Shares by the date that is twenty-four months after the vesting date. Vested Shares As the exchange of Vested Shares are contingently redeemable at the option of the noncontrolling interest shareholders, the Company classifies the carrying amount of the redeemable noncontrolling interest in the mezzanine section on the consolidated balance sheet, which is presented above the equity section and below liabilities. Adjustments to the carrying value of the redeemable noncontrolling interest associated with redemptions are recorded by reclassifying the proportionate amount of mezzanine equity to permanent equity. Earnout Shares The Earnout Shares vest (the “Released Earnout Shares”) in two equal tranches based upon achieving market share price milestones of approximately $12.00 per Common Share and approximately $15.00 per Common Share, respectively, prior to the Ten-Year Anniversary, or upon a change in control as defined in the underlying agreement. These shares will be forfeited if the market share price milestones or an acceleration event is not reached prior to the Ten-Year Anniversary. At such time that the Earnout Shares shall become vested, and therefore, become Released Earnout Shares, the shares will be transferred to the redeemable noncontrolling interest in the mezzanine section of the Consolidated Balance Sheet. The Earnout Shares were classified as a liability due to failure to meet the equity classification criteria under ASC 815-40, as Level 3 instruments under the fair value hierarchy and are considered a financial liability under ASC 480, Distinguishing Liabilities from Equity. The Earnout Shares were measured at fair value on the Closing Date with subsequent changes in fair value recorded in earnings. The Earnout Shares were valued utilizing a Monte Carlo simulation pricing model with an expiry date of March 17, 2033. The following table discloses the primary inputs into the Monte Carlo models: Key Valuation Input June 30, 2026 June 30, 2025 June 30, 2024 Closing Common Share price $4.82 $2.33 $1.73 Term (expiry) March 17, 2033 March 17, 2033 March 17, 2033 Implied volatility of the 2023 Public Warrants 84.0% 75.0% 65.0% Risk-free rate 4.28% 4.04% 4.35% The following table sets forth a summary of the changes in the fair value of the Earnout Shares liability for the year ended June 30, 2026:
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 69 Amount Fair value as of June 30, 2024 $ 3,817 Change in fair value 2,063 Fair value as of June 30, 2025 5,880 Change in fair value 8,571 Fair value as of June 30, 2026 $ 14,451 9. COMMON SHARES a) Issuances Fiscal Year 2026 Issuances On July 18, 2025, the Company issued and sold 13,850,000 Common Shares, at an offering price of $3.25 per Common Share, in a registered offering (the “July 2025 Offering”) under the Company’s registration statement on Form S-3 (Registration No. 333- 280176), pursuant to the Placement Agency Agreement between the Company and Maxim Group LLC (“Maxim”), dated July 17, 2025. The Company received net proceeds from the July 2025 Offering, after deducting placement agent fees and other offering expenses payable by the Company, of approximately $41,335. On September 19, 2025, the Company issued and sold 10,000,000 Common Shares, at an offering price of $5.00 per Common Share, in a registered direct offering (the “September 2025 Registered Direct Offering”) under the Company’s registration statement on Form S-3 (Registration No. 333-280176), pursuant to the Placement Agency Agreement between the Company and Maxim, dated September 17, 2025. The Company received net proceeds from the September 2025 Registered Direct Offering, after deducting placement agent fees and other offering expenses payable by the Company, of approximately $46,048. On September 29, 2025, the Company issued and sold (a) 7,004,740 Common Shares at a public offering price of $6.15 per Common Share and (b) 2,755,260 pre-funded Warrants to purchase an aggregate of 2,755,260 Common Shares (the “September Pre-Funded Warrants”) at a public offering price of $6.1499 per September Pre-Funded Warrant in a confidentially marketed public offering (the “September 2025 Public Offering”) under the Company’s registration statement on Form S-3 (Registration No. 333-280176), pursuant to the Placement Agency Agreement between the Company and Maxim, dated September 26, 2025. On September 30, 2025, the Company issued 2,755,218 Common Shares in connection with the cashless exercise of all of the outstanding September Pre-Funded Warrants. The Company received net proceeds from the September 2025 Public Offering, after deducting placement agent fees and other offering expenses payable by the Company, of approximately $55,365. On October 15, 2025, the Company issued and sold (a) 10,152,175 Common Shares at an offering price of $9.34 per Common Share and (b) 5,925,000 pre-funded Warrants (the “October Pre-Funded Warrants”) to purchase up to an additional 5,925,000 Common Shares at an offering price of $9.3399 per October Pre-Funded Warrant in a registered offering (the “October 2025 Offering”) under the Company's registration statement on Form S-3 (Registration No. 333-290837), pursuant to the Placement Agency Agreement between the Company and Maxim, dated October 13, 2025. On October 17, 2025, the Company issued 5,924,942 Common Shares in connection with the cashless exercise of all of the outstanding October Pre-Funded Warrants. The Company received net proceeds from the October 2025 Offering, after deducting placement agent fees and other offering expenses payable by the Company, of approximately $138,974. On February 25, 2026, the Company issued and sold (a) 17,400,000 Common Shares at an offering price of $5.00 per Common Share and (b) 2,600,000 pre-funded Warrants (the “February Pre-Funded Warrants”) to purchase up to an additional 2,600,000 Common Shares at an offering price of $4.9999 per February Pre-Funded Warrant in a registered offering (the “February 2026 Offering”) under the Company's registration statement on Form S-3 (Registration No. 333-290837), pursuant to the Placement Agency Agreement between the Company and Maxim, dated February 24, 2026. On February 25, 2026 and March 4, 2026, the Company issued a total of 2,599,951 Common Shares in connection with the cashless exercise of all of the outstanding February Pre-Funded Warrants. The Company received net proceeds from the February 2026 Offering, after deducting placement agent fees and other offering expenses payable by the Company, of approximately $93,406. Fiscal Year 2025 Issuances
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 70 On November 5, 2024, the Company closed an underwritten public offering (the “November 2024 Registered Offering”), pursuant to the underwriting agreement, dated November 3, 2024 (the “November 2024 Underwriting Agreement”), with Maxim, as underwriter, which consisted of 1,592,356 Common Shares, 1,672,090 Warrants (the “Series A Public Warrants”) to purchase up to an additional 1,672,090 Common Shares and 836,045 Warrants (the “Series B Public Warrants” and, together with the Series A Public Warrants, the “November 2024 Public Warrants”) to purchase up to an additional 836,045 Common Shares. Each Common Share was sold together with one Series A Public Warrant and one-half of one Series B Public Warrant at a combined public offering price of $1.57. The gross proceeds from the November 2024 Registered Offering were $2,501 before deducting underwriting discounts and offering expenses. The November 2024 Public Warrants were classified as equity instruments and accordingly, the net proceeds were allocated based on the relative fair values of the Common Shares and the November 2024 Public Warrants on the date of issuance, with $943 allocated to the fair value of the November 2024 Public Warrants and the balance of the proceeds of $1,558 allocated to Common Shares. The Company incurred total transaction costs related to the November 2024 Registered Offering of $1,226, which were treated as share issuance costs at closing. The Series A Public Warrants have an exercise price of $1.75 per underlying Common Share, are exercisable immediately, and will expire on November 5, 2026. The Series B Public Warrants have an exercise price of $2.07 per underlying Common Share, are exercisable beginning six months and one day from the date of issuance and will expire on November 5, 2029. In addition, pursuant to the November 2024 Underwriting Agreement, the Company granted Maxim a 45-day over-allotment option to purchase (i) 238,853 additional Common Shares and (ii) 358,280 Option Warrants (as defined below) to purchase up to an aggregate of 358,280 Common Shares. “Option Warrant” means one Series A Public Warrant combined with one-half of one Series B Public Warrant. On November 4, 2024, Maxim partially exercised its over-allotment option to purchase 79,734 additional Series A Public Warrants and 39,867 additional Series B Public Warrants, which amounts are included in the amounts discussed above and were issued at closing of the November 2024 Registered Offering. The following table discloses the primary inputs for the Black-Scholes model used in valuing the November 2024 Public Warrants: November 5, 2024 November 2024 Public Warrants: Series A Public Warrants Series B Public Warrants Closing Common Share price $ 1.455 $ 1.455 Term (years) 4.5 2.0 Historic equity volatility 67.43% 67.13% Risk-free rate 4.14% 4.20% On November 13, 2024, the Company closed a non-brokered private placement (the “November 2024 Private Offering”), pursuant to binding subscription agreements with certain accredited investors as part of a non-brokered private placement of 2,199,602 units of the Company (the “November 2024 Units”). Each November 2024 Unit consisted of one Common Share, one Warrant (a “Series A Private Warrant”) to purchase one Common Share, and one-half of one Warrant (each whole such Warrant, a “Series B Private Warrant” and, together with the Series A Private Warrants, the “November 2024 Private Warrants”), with each Series B Private Warrant entitling the holder thereof to purchase one additional Common Share. Each November 2024 Unit was issued and sold at a price of $1.57. The gross proceeds of the November 2024 Private Offering were approximately $3,500 before deducting offering expenses. Certain directors and officers of the Company (the “Insider Investors”) purchased November 2024 Units at a price of $1.7675 per November 2024 Unit, which price includes $0.1975 per November 2024 Private Warrant and allowed such directors and officers to participate in the November 2024 Private Offering in accordance with the rules of the Nasdaq. The Series A Private Warrants have an exercise price of $1.75 per underlying Common Share, are exercisable immediately, and will expire on November 13, 2026. The Series B Private Warrants have an exercise price of $2.07 per underlying Common Share, are exercisable beginning six months and one day from the date of issuance and will expire on November 13, 2029. The Company recorded a non-cash expense of $34 and $110 to other operating expenses and employee related costs, respectively, representing the excess of fair value of the November 2024 Units over the purchase price paid by Insider Investors. Based upon the Company’s analysis of the criteria contained in ASC 815, the Company determined that the November 2024 Private Warrants met the definition of a derivative liability, as any Warrant exercise that could
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) cause the holder to exceed 19.9% ownership of NioCorp Common Shares would require shareholder approval. As such, the November 2024 Private Warrants were recognized as warrant liabilities on the consolidated balance sheet and were measured at their issuance date fair value of $1,928 and subsequently remeasured at each reporting period with changes being recorded as a non-operating gain or loss in the consolidated statement of operations and comprehensive loss. The remaining proceeds of the November 2024 Private Offering of $1,573 were allocated to Common Shares. The Company incurred total transaction costs related to the November 2024 Private Offering of $161, of which $60 was allocated to the November 2024 Private Warrants and was expensed at closing. The following tables disclose the primary inputs for the Black-Scholes model used in valuing the November 2024 Private Warrants: November 13, 2024 November 2024 Private Warrants: Series A Private Warrants Series B Private Warrants Closing Common Share price $ 1.49 $ 1.49 Term (years) 2.0 4.5 Historic equity volatility 67.26% 67.52% Risk-free rate 4.20% 4.30% June 30, 2026 November 2024 Private Warrants: Series A Private Warrants Series B Private Warrants Closing Common Share price $ 4.82 $ 4.82 Term (years) 0.37 3.38 Historic equity volatility 65.66% 81.83% Risk-free rate 3.89% 4.20% The following table sets forth a summary of the changes in the fair value of the November 2024 Private Warrants liabilities. November 2024 Private Warrants Fair value at issuance (November 13, 2024) $ 1,929 Fair value of Warrants exercised (338) Change in fair value 2,240 Fair value as of June 30, 2025 3,831 Fair value of Warrants exercised (4,833) Change in fair value 8,353 Fair value as of June 30, 2026 $ 7,351 On January 31, 2025, the Company closed an underwritten registered direct offering (the “January 2025 Offering”), pursuant to an underwriting agreement, dated January 29, 2025, with Maxim, as underwriter, pursuant to which the Company issued and sold 2,577,320 Common Shares, 2,577,320 Series A Warrants to purchase up to 2,577,320 Common Shares (the “January 2025 Series A Warrants”) and 1,288,660 Series B Warrants to purchase up to an additional 1,288,660 Common Shares (the “January 2025 Series B Warrants” and, together with the January 2025 Series A Warrants, the “January 2025 Warrants”). Each Common Share was sold together with one January 2025 Series A Warrant and one-half of one January 2025 Series B Warrant at a combined public offering price of $1.94. The gross proceeds from the January 2025 Offering were approximately $5,000 before deducting underwriting discounts and offering expenses. The January 2025 Warrants were classified as equity instruments, and accordingly, the net proceeds were allocated based on the relative fair values of the Common Shares and the January 2025 Warrants on the date of issuance, with $2,200 allocated to the fair value of the January 2025 Warrants and the balance of the proceeds of $2,800 allocated to Common Shares. The Company incurred total transaction costs related to the January 2025 Offering of $799, which were treated as share issuance costs at closing. The January
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 72 2025 Series A Warrants have an exercise price of $1.98 per underlying Common Share, are exercisable immediately, and will expire on August 2, 2027. The January 2025 Series B Warrants have an exercise price of $2.05 per underlying Common Share, are exercisable immediately, and will expire on January 31, 2029. The following primary inputs were used in the Black-Scholes model for valuing the January 2025 Warrants: January 2025 Series A Warrants January 2025 Series B Warrants Closing Common Share price $ 2.25 $ 2.25 Term (years) 2.5 4.0 Historic equity volatility 73.18% 73.36% Risk-free rate 4.23% 4.31% On April 21, 2025, the Company closed an underwritten public offering (the “April 2025 Offering”), pursuant to an underwriting agreement, dated April 17, 2025, with Maxim, as underwriter, pursuant to which the Company issued and sold (i) 6,628,846 Common Shares at a public offering price of $2.60 per Common Share and (ii) 1,063,462 pre-funded Warrants (the “April 2025 Pre-Funded Warrants”) to purchase up to an additional 1,063,462 Common Shares at a public offering price of $2.5999. The April 2025 Pre-Funded Warrants have an exercise price of $0.0001 per underlying Common Share, are exercisable immediately, and do not have an expiration date. On April 17, 2025, Maxim partially exercised its over-allotment option to purchase 323,504 additional Common Shares at closing. The gross proceeds from the April 2025 Offering were approximately $20,841 before deducting underwriting discounts and offering expenses. The April 2025 Pre-Funded Warrants were classified as equity instruments and accordingly, the net proceeds were allocated based on the relative fair values of the Common Shares and the April 2025 Pre-Funded Warrants on the date of issuance, with $2,765 allocated to the fair value of the April 2025 Pre-Funded Warrants (based on the value of the underlying Common Shares at closing) and the balance of the proceeds of $18,076 allocated to Common Shares. The Company incurred total transaction costs related to the April 2025 Offering of $2,102, which were treated as share issuance costs at closing. Yorkville Equity Facility Financing Agreement Issuances The Company entered into a Standby Equity Purchase Agreement, dated January 26, 2023 (the “Yorkville Equity Facility Financing Agreement”) between the Company and YA II PN, Ltd., an investment fund managed by Yorkville Advisors Global, LP (“Yorkville”) which expired on April 1, 2026. The Company issued the following Common Shares under the Yorkville Equity Facility Financing Agreement during the periods presented below: For The Year Ended June 30, 2026 2025 Common Shares issued 5,727,662 5,671,742 Gross funds received $ 38,710 $ 12,352 Market value of Common Shares issued 39,434 12,941 Loss on issuance $ 724 $ 589 (1) Loss on issuance represents a non-cash amount equal to the difference between the proceeds received and the fair value of the Common Shares issued based on the Nasdaq closing price per Common Share on the issuance date and is recorded in general and administrative expenditures in the consolidated statement of operations and comprehensive loss. b) Stock Options On April 6, 2026, the Company’s shareholders voted to approve an amendment and restatement of its long-term incentive plan, the NioCorp Developments Ltd. Long Term Incentive Plan (as amended, the “2017 Amended Long-Term Incentive Plan”). Under the 2017 Amended Long-Term Incentive Plan, the Board may, in its discretion from time to time, grant Options and share units (in the form of restricted share units and performance share units), plus dividend equivalents, to non-employee directors, employees and certain other service providers (as described in the 2017 Amended Long-Term Incentive Plan) of the Company and affiliated entities selected by the Board. (1)
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 73 Subject to adjustment as described in the 2017 Amended Long-Term Incentive Plan, and subject to the plan's share counting rules, the aggregate number of Common Shares available for awards under the 2017 Amended Long-Term Incentive Plan may not exceed 11,300,000 Common Shares, minus, as of April 5, 2026, one Common Share for every one Common Share subject to an award granted under the 2017 Amended Long-Term Incentive Plan after February 9, 2026 and before April 6, 2026. The 2017 Amended Long-Term Incentive Plan also limits the maximum annual compensation that may be granted to our non-employee directors for service on the Board to $750 (measured as described in the plan document), subject to exceptions for distributions of previously deferred compensation for services as an executive officer or employee, and non-preferential dividends or dividend equivalents. The Board has power over the granting, amendment, administration, or settlement of any award. Option transactions are summarized as follows: Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Life Balance, June 30, 2024 2,495,500 4.78 Granted 945,000 1.41 Exercised (512) 1.40 Cancelled/expired (419,988) 9.44 Balance, June 30, 2025 3,020,000 3.09 Granted 2,282,500 4.68 Exercised (567,000) 3.28 Cancelled/expired (588,000) 6.77 Balance, June 30, 2026 4,147,500 3.42 $6,210 3.5 Years As of June 30, 2026, 53.3% of the outstanding Options were fully vested. The total intrinsic value of Options exercised during the year ended June 30, 2026 was $1,654, and as of June 30, 2026, there was $1,540 of unrecognized compensation costs related to unvested share-based compensation arrangements granted. The Company recognized share-based compensation expense of $4,441 and $789 for the years ended June 30, 2026 and 2025, respectively. The following table summarizes the weighted average information and assumptions used to determine Option costs: For the year ended June 30, 2026 2025 Fair value per option granted during the period $2.84 $0.84 Risk-free interest rate 3.84% 4.44% Expected dividend yield 0% 0% Expected stock price volatility (historical basis) 76.8% 67.3% Expected option life in years 4.6 5.0
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 74 c) Warrants Warrant transactions are summarized as follows. Weighted average exercise prices related to Canadian dollar denominated Warrants were converted to U.S. dollars using end of period foreign currency exchange rates. Warrants Weighted Average Exercise Price Balance, June 30, 2024 18,563,561 $10.53 Granted 13,553,714 2.05 Exercised (828,235) 1.78 Expired (1,303,118) 7.72 Balance, June 30, 2025 29,985,922 $7.06 Granted 11,280,260 0.0001 Exercised (22,308,402) 0.98 Expired (250,000) 4.60 Balance, June 30, 2026 18,707,780 $9.94 At June 30, 2026, the Company has outstanding exercisable Warrants, as follows: Number Exercise Price Expiry Date 279,000 1.75 November 5, 2026 1,487,111 1.75 November 13, 2026 15,666,526 11.50 March 17, 2028 296,742 2.31 September 17, 2028 217,295 2.07 November 5, 2029 761,106 2.07 November 13, 2029 18,707,780 (1) Includes 13,447,105 and 2,219,421 2023 Public Warrants and 2023 Private Warrants, respectively, as defined below. Each 2023 Public Warrant and 2023 Private Warrant is exercisable into 1.11829212 Common Shares. In connection with the Closing, pursuant to the Business Combination Agreement, the Company assumed GXII’s obligations under the agreement (the “GXII Warrant Agreement”) governing the GXII share purchase Warrants (the “GXII Warrants”) and each GXII Warrant thereunder that was issued and outstanding immediately prior to the Closing Date was converted into one Warrant to purchase 1.11829212 Common Shares (the “NioCorp Assumed Warrants”) pursuant to the GXII Warrant Agreement, as amended by an Assignment, Assumption and Amendment Agreement, dated March 17, 2023, among the Company, GXII, Continental Stock Transfer & Trust Company, as the existing warrant agent, and Computershare Inc. and its affiliate, Computershare Trust Company, N.A, together as the successor warrant agent (the “NioCorp Assumed Warrant Agreement”). In connection with the Closing, NioCorp issued (a) 9,999,959 public NioCorp Assumed Warrants (the “2023 Public Warrants”) in respect of the GXII Warrants that were publicly traded prior to the Closing and (b) 5,666,667 NioCorp Assumed Warrants (the “2023 Private Warrants”) to the Sponsor in respect of the GXII Warrants that it held prior to the Closing, which NioCorp Assumed Warrants were subsequently distributed by the Sponsor to its members in connection with the Closing. Each NioCorp Assumed Warrant entitles the holder to the right to purchase 1.11829212 Common Shares at an exercise price of $11.50 per 1.11829212 Common Shares (subject to adjustments for stock splits, stock dividends, reorganizations, recapitalizations and the like). No fractional shares will be issued upon exercise of any NioCorp Assumed Warrants, and fractional shares that would otherwise be due to the exercising holder will be rounded down to the nearest whole Common Share. In no event will the Company be required to net cash settle any NioCorp Assumed Warrant. 2023 Public Warrants The Company may elect to redeem the 2023 Public Warrants subject to certain conditions, in whole and not in part, at a price of $0.01 per 2023 Public Warrant if (i) 30 days’ prior written notice of redemption is provided to the (1)
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 75 holders, (ii) the last reported sale price of the Common Shares equals or exceeds approximately $16.10 per share (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days within a 30-trading day period ending on the third business day prior to the date on which the Company sends the notice of redemption to the Warrant holders and (iii) there is an effective registration statement covering the Common Shares issuable upon exercise of the 2023 Public Warrants, and a current prospectus relating thereto, available through the redemption date. Upon issuance of a redemption notice by the Company, the Warrant holders will have until the redemption date to exercise for cash, or, at the Company’s election, on a cashless basis. 2023 Private Warrants The 2023 Private Warrants: (i) will be exercisable either for cash or on a cashless basis at the holder’s option and (ii) will not be redeemable by the Company, in either case as long as the 2023 Private Warrants are held by the initial purchasers or their permitted transferees. Any 2023 Private Warrants that are held by someone other than the initial purchasers or their permitted transferees are treated as 2023 Public Warrants. The Company accounts for the 2023 Private Warrants in accordance with the guidance contained in ASC 815-40. Such guidance provides that because the 2023 Private Warrants do not meet the criteria for equity treatment thereunder, the 2023 Private Warrants must be recorded as a liability. This liability is carried as a component of Warrant liabilities on the consolidated balance sheet and is subject to re-measurement at each balance sheet date. With each such re-measurement, the warrant liability will be adjusted to its current fair value, with the change in fair value recognized in the consolidated statement of operations and comprehensive loss. The Company will reassess the classification at each balance sheet date. As provided for in the NioCorp Assumed Warrant Agreement, through June 30, 2026, a total of 3,447,246 2023 Private Warrants were exchanged for 2023 Public Warrants. The Company recorded a non-cash loss of $1,217 and $26 for the years ending June 30, 2026 and 2025, respectively, in change in fair value of warrant liabilities in the consolidated statement of operations, representing the change in fair value of the 2023 Private Warrants through the respective exercise dates. The Company classifies the 2023 Private Warrants as Level 2 instruments under the fair value hierarchy and estimated the fair value using a Black Scholes model with the following assumptions: Key Valuation Input June 30, 2026 June 30, 2025 Stock price on valuation date $ 4.82 $ 2.33 Strike price $ 11.50 $ 11.50 Implied volatility of the 2023 Public Warrants 99.0% 90.0% Risk free rate 4.14% 3.70% Dividend yield 0% 0% Expected Warrant life in years 1.7 2.7 The change in the 2023 Private Warrants liability is presented below: Amount Valuation at June 30, 2024 $ 1,353 Exchange of 2023 Private Warrants for 2023 Public Warrants (482) Change in valuation 1,661 Valuation at June 30, 2025 $ 2,532 Exchange of 2023 Private Warrants for 2023 Public Warrants (2,501) Change in valuation 3,364 Valuation at June 30, 2026 $ 3,395 Contingent Consent Warrants As consideration for entering into the previously publicly disclosed Waiver and Consent Agreement, dated September 25, 2022 (the “Lind Consent”), between the Company and Lind Global Asset Management III, LLC (“Lind III”), Lind III received, amongst other things, the right to receive additional Warrants (the “Contingent
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 76 Consent Warrants”) if on September 17, 2024, the closing trading price of the Common Shares on the Toronto Stock Exchange or such other stock exchange on which such shares may then be listed, is less than C$10.00, subject to adjustments. The number of Contingent Consent Warrants to be issued, if any, is based on the Canadian dollar equivalent (based on the then current Canadian to U.S. dollar exchange rate as reported by Bloomberg, L.P.) of $5,000 divided by the five-day volume weighted average price of the Common Shares on the date of issuance. Further, the number of Contingent Consent Warrants issued would be proportionately adjusted based on the percentage of Warrants currently held by Lind III that are exercised, if any, prior to the issuance of any Contingent Consent Warrants. On September 17, 2024, the Company’s Common Share price was below the threshold price set forth in the Lind Consent, and accordingly, the Company issued 2,816,742 Contingent Consent Warrants to Lind III. Each Contingent Consent Warrant is exercisable for one Common Share at an exercise price of $2.308 and may be exercised at any time prior to their expiration on September 17, 2028. The number of Contingent Consent Warrants issued was based on $5,000 divided by the five-day volume weighted average price of the Common Shares on September 16, 2024. The Company valued the Contingent Consent Warrants at $2,262 based on a Black-Scholes valuation with the following inputs: Key Valuation Input September 17, 2024 Closing Common Share price $1.74 Term (years) 4.0 Historic equity volatility 67.14% Risk-free rate 3.44% The change in the fair value of the Contingent Consent Warrants liability is presented below: Amount Valuation at June 30, 2024 $ 2,365 Fair value of Warrants issued (2,262) Gain on issuance of Warrants (103) Ending balance $ — The Company recognized a gain of $103 on the issuance of the Contingent Consent Warrants. This gain was recorded as a part of other non-operating expense (income) in the consolidated statements of operations and comprehensive loss. April 2024 Warrants As previously disclosed, on April 12, 2024, the Company issued and sold to Yorkville and Lind Global Fund II LP (together with Yorkville, the “April 2024 Purchasers”) $8,000 aggregate principal amount of unsecured notes (the “April 2024 Notes”), pursuant to a securities purchase agreement, dated April 11, 2024, between the Company and each of the April 2024 Purchasers. The Company also issued to the April 2024 Purchasers, in proportion to the aggregate principal amount of April 2024 Notes issued to each April 2024 Purchaser, Warrants (the “April 2024 Warrants”) to purchase up to 615,385 Common Shares, which are equal to 25% of the aggregate principal amount of April 2024 Notes issued to the April 2024 Purchasers divided by the exercise price of $3.25, subject to any adjustment to give effect to any stock dividend, stock split or recapitalization. The Company accounted for the April 2024 Warrants in accordance with ASC Topic 815, Derivatives and Hedging, and determined that at issuance, the April 2024 Warrants should be classified as a warrant liability. During the three-month period ended September 30, 2025, all of the outstanding April 2024 Warrants were exercised.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 77 The change in the April 2024 Warrant liability is presented below: Amount Fair value as of June 30, 2024 $ 298 Change in fair value 191 Fair value as of June 30, 2025 489 Fair value of Warrants exercised (1,807) Change in fair value 1,318 Fair value as of June 30, 2026 $ — d) Shareholder Rights Plan On November 21, 2025, the Company adopted a limited-duration shareholder rights plan (the "Rights Plan") pursuant to a Shareholder Rights Plan Agreement dated November 21, 2025 (the "Original Rights Plan Agreement"), between the Company and Computershare Investor Services Inc., as rights agent (the "Rights Agent"). One right (a "Right") was issued for each Common Share outstanding as of December 4, 2025, and a Right automatically attaches to each Common Share subsequently issued until the expiration of the Rights Plan. The Rights generally become exercisable only if a person or group acquires, or announces the current intention of commencing a take-over bid to acquire, beneficial ownership of 20% or more of the Company's outstanding Common Shares, other than through a permitted bid made in compliance with applicable Canadian take- over bid rules. If the Rights become exercisable, each holder of a Right, other than the acquiring person, would be entitled to purchase additional Common Shares at a discount to the then-current market price. The Rights Plan was not adopted in response to any specific take-over proposal. On April 6, 2026, following approval by the Company's shareholders at the Company's annual general meeting, the Company and the Rights Agent entered into an Amended and Restated Shareholder Rights Plan Agreement (the "Amended Rights Plan Agreement"), which amended and restated the Original Rights Plan Agreement in its entirety. Under the Amended Rights Plan Agreement, the Rights Plan expires at 5:00 p.m. (Toronto time) on the date of the Company's annual general meeting of shareholders to be held in 2027, or earlier upon the redemption of the Rights or, provided that a triggering event has not occurred, at such earlier date or time as the Board of Directors may determine in its sole discretion. Neither the adoption of the Original Rights Plan Agreement nor the subsequent entry into the Amended Rights Plan Agreement had an impact on the Company's consolidated financial statements for the year ended June 30, 2026. 10. RELATED PARTY TRANSACTIONS AND BALANCES On September 11, 2024, the Company and Mark Smith, Chief Executive Officer, President, Executive Chairman, and Director of NioCorp, entered into a loan agreement (the “Smith Loan Agreement”), which provided for a $2,000 non-revolving, multi-draw credit facility (the “Smith Loan”). The Smith Loan had an interest rate of 10% per annum, calculated monthly in arrears, through the date of repayment of the Smith Loan. The Company could pre-pay the Smith Loan at any time without notice and without penalty, but any amount of principal or interest repaid by the Company prior to the earlier of the date of expiration of the Smith Loan Agreement, on June 30, 2025, and the occurrence of an event of default under the Smith Loan Agreement was subject to an early payment fee of 2.5% of the value of any such payment. The Smith Loan was secured by all of the Company’s assets pursuant to a general security agreement between the Company and Mr. Smith dated September 11, 2024. Through October 30, 2024, the Company borrowed a total of $504 under the Smith Loan and subsequently the Company repaid $508, representing the balance of interest and principal outstanding under the Smith Loan, together with $41 related to loan origination fees payable. The Smith Loan expired on June 30, 2025.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 78 11. EXPLORATION EXPENDITURES For the year ended June 30, 2026 2025 Feasibility study and engineering $10,354 $1,112 Field management and other 2,765 900 Drilling 2,527 1,456 Metallurgical 1,355 214 Geologists and field staff 1,038 453 Subtotal 18,039 4,135 Less: reimbursements recognized (1,963) — Total $16,076 $4,135 On August 4, 2025, ECRC entered into a Project Sub-Agreement (the “DoW Agreement”) with Advanced Technology International, an entity acting on behalf of the Defense Industrial Base Consortium under the authority of the U.S. Department of War (“DoW”). The DoW Agreement commenced upon full execution and has an initial term through December 30, 2028, with an option to extend the term for an additional five-year period through December 30, 2033. Subject to the terms and conditions of the DoW Agreement, ECRC is entitled to receive up to an aggregate of approximately $10.0 million of reimbursement payments from the DoW upon the achievement of certain project milestones. These milestones include, among other matters, the completion of new drilling operations at the Elk Creek Project to support the conversion of a portion of the current indicated mineral resources into measured mineral resources and the subsequent conversion of a portion of the current probable mineral reserves into proven mineral reserves, the production of samples of scandium metal and aluminum-scandium master alloys, and the completion of a new feasibility study for the Elk Creek Project. Reductions to exploration expenditures for reimbursement under the DoW Agreement will be recognized based on management’s assessment regarding the achievement of milestones set forth in the DoW Agreement. Since inception of the DoW Agreement, the Company recognized a total of $1,963 as a reduction to exploration expenditures. As of June 30, 2026, the Company’s deferred reimbursements balance is $6,177. 12. LEASES The Company has one immaterial operating lease for office space. In October 2025 the lease was amended and in May 2026 the Company exercised an option to shorten the lease term to January 31, 2027. These lease remeasurements were made in accordance with ASC 842. The Company incurred lease costs as follows: For the year ended June 30, 2026 2025 Fixed rent expense $ 184 $ 94 Variable rent expense 15 13 Short term lease cost 11 10 Sublease income (59) (41) Net lease cost – other operating expense $ 151 $ 76 The maturity of lease liabilities is as follows at June 30, 2026: Fiscal Year Lease Maturities 2027 $ 96 Less amount of payments representing interest (2) Lease liability $ 94
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 79 13. INCOME TAXES Domestic and foreign components of loss before income taxes for the years ended June 30, 2026 and 2025 are as follows: For the year ended June 30, 2026 2025 Canada $(29,649) $(13,089) United States (21,053) (4,818) United Kingdom (79) (75) Total $(50,781) $(17,982) The following table is a reconciliation of income taxes at statutory rates: For the year ended June 30, 2026 2025 $ % $ % Income tax benefit at Canadian federal statutory rate $(7,617) 15.00% $(2,697) 15.00% Provincial income tax (3,558) 7.01% $(1,571) 8.74% Non-taxable/non-deductible items: Stock issuance costs in equity (8,119) 15.99% $(1,143) 6.36% Warrant liabilities 3,519 (6.93)% $1,105 (6.15)% Earnout share liability 2,314 (4.56)% $557 (3.10)% Share based payments 822 (1.62)% $194 (1.08)% Other 208 (0.41)% $5 (0.03)% Change in valuation allowance 9,249 (18.21)% 2,804 (15.59)% Other 12 (0.02)% 13 (0.07)% Foreign Tax Effects United States: Foreign rate differences (2,105) 4.15% (482) 2.68% Change in valuation allowance 4,908 (9.67)% 1,159 (6.45)% Other 355 (0.71)% 45 (0.25)% Other foreign jurisdictions 12 (0.02)% 11 (0.06)% Total $— 0.00% $— 0.00% The provincial income tax rate reflects the statutory general corporate income tax rate of 12% applicable in the Province of British Columbia. Income tax benefit was $0 in each of the Canadian federal, Canadian provincial, U.S., and U.K. jurisdictions for the years ended June 30, 2026 and 2025. In addition, during the years ended June 30, 2026 and 2025, the Company did not pay any income taxes, net of refunds received, in Canada, the United States, or the United Kingdom. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The significant components of deferred taxes are as follows:
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 80 As of June 30, 2026 2025 Deferred tax assets Mineral interests $13,562 $10,438 Net operating losses available for future periods 20,424 16,125 Startup and organizational costs 1,697 1,842 Research and development costs 2,120 1,295 Share issuance/financing costs 7,420 1,357 Canadian restricted interest and financing carryforward 605 605 Capital losses available for future periods 457 456 Other 50 41 Total deferred tax assets 46,335 32,159 Valuation allowance (46,335) (32,159) Net deferred tax assets $— $— Changes in the valuation allowance are as follows: For the year ended June 30, 2026 2025 Valuation allowance, beginning of year $(32,159) $(28,181) Current year additions (14,176) (3,978) Valuation allowance, end of year $(46,335) $(32,159) The Company establishes a valuation allowance against future income tax assets if, based on available information, it is more likely than not that all of the assets will not be realized. The valuation allowance of $46,335 at June 30, 2026, relates mainly to net operating loss carryforwards in Canada and mineral interests due to deferred exploration expenditures in the United States, where the utilization of such attributes is not more likely than not. The Company has the following cumulative net operating losses for Canadian and U.S. Federal income tax purposes. Canadian tax loss carryforwards will generally expire between 2028 and 2045. U.S. tax losses incurred through June 30, 2018, totaled $981 and will generally expire between 2031 and 2038. As a result of the Tax Cuts and Jobs Act of 2017, U.S. tax losses incurred for our tax years ending on and after June 30, 2019, totaling $10,027, have no expiration. As of June 30, Jurisdiction 2026 2025 Canada $64,990 $53,194 United States 11,008 6,627 United Kingdom 208 112 Total $76,206 $59,933 In addition, the Company has a Canadian capital loss carryforward of $3,388 as of June 30, 2026, which has no expiration date and can be used to offset future capital gains, and U.S. state net operating loss carryforwards of $13,124 as of June 30, 2026 which generally expire between 2031 and 2046. At June 30, 2026 and 2025, we had no undistributed earnings of foreign subsidiaries that would be subject to income tax upon distribution to Canada from a foreign subsidiary. As such, as of June 30, 2026 and 2025, we did not provide for deferred taxes on any such earnings of our foreign subsidiaries. The Company had no unrecognized tax benefits as of June 30, 2026 or 2025. The Company has not recognized any interest or penalties in the fiscal years presented in these consolidated financial statements. The Company is subject to income tax in the U.S. federal jurisdiction, the United Kingdom, and Canada. Certain years remain subject to examination by the applicable tax authorities.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 81 On July 4, 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted in the U.S., which includes a broad range of tax reform provisions affecting businesses. The OBBBA includes numerous changes to existing tax law including extending or making permanent certain business and international tax measures initially established under the 2017 Tax Cuts and Jobs Act, which were set to expire. The OBBBA contains several changes to corporate taxation including modifications to capitalization of research and development expenses, modifications to deductions for interest expense, and accelerated depreciation on certain asset additions. The OBBBA was enacted during the year ended June 30, 2026. Given the Company's full valuation allowance against its net deferred tax assets, the enactment of the OBBBA did not have a material impact on the Company's income tax provision or effective tax rate for the year ended June 30, 2026. 14. FAIR VALUE MEASUREMENTS The Company measures the fair value of financial assets and liabilities in accordance with ASC 820, Fair Value Measurement, which establishes a framework for measuring fair value and a three-tier hierarchy that prioritizes the inputs used in valuation techniques. Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, including quoted prices for similar instruments in active markets and quoted prices for identical or similar instruments in markets that are not active. Level 3 inputs are unobservable and reflect the Company's own assumptions about the assumptions market participants would use in pricing the asset or liability. Cash and cash equivalents, restricted cash, receivables, accounts payable, and accrued liabilities are carried at amortized cost, which management believes approximates fair value due to the short-term nature of these instruments. The following tables present information about the assets and liabilities measured at fair value on a recurring basis as of June 30, 2026 and 2025. As of June 30, 2026 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 415,004 $ 415,004 $ — $ — Restricted cash 2,102 2,102 — — Total $ 417,106 $ 417,106 $ — $ — Liabilities: Earnout Shares liability $ 14,451 $ — $ — $ 14,451 Warrant liabilities 10,746 — 10,746 — Total $ 25,197 $ — $ 10,746 $ 14,451 As of June 30, 2025 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 25,554 $ 25,554 $ — $ — Investment in equity securities 3 3 — — Total $ 25,557 $ 25,557 $ — $ — Liabilities: Earnout Shares liability $ 5,880 $ — $ — $ 5,880 Warrant liabilities 6,852 — 6,852 — Total $ 12,732 $ — $ 6,852 $ 5,880 15. SEGMENT INFORMATION The Company has one reportable segment: the United States. The United States segment conducts exploration, development, and care and maintenance activities at the Elk Creek Project. This segment holds substantially all of the Company’s non-current assets and does not presently report any revenues from operations. Through this segment, the Company seeks to position the Elk Creek Project as a development opportunity in the strategic minerals sector. The Company’s Chief Operating Decision Maker ("CODM") is the Chief Executive Officer.
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NioCorp Developments Ltd. Notes to the Consolidated Financial Statements June 30, 2026 (expressed in thousands of U.S. dollars, except share and per share data or as otherwise stated) 82 Financial information and annual operating plans and forecasts are prepared and reviewed by the CODM at a consolidated level. The CODM assesses performance for the single operating segment and decides how to better allocate resources based on total operating expenses, net loss, changes in cash and cash equivalents, and cash and cash-equivalent balances that are reported on the Consolidated Statement of Operations and Consolidated Statement of Cash Flows. The Company's objective in making resource allocation decisions is to optimize the Company’s ability to develop and operate the Elk Creek Project. In addition, the CODM reviews the segment’s assets based on total assets reported on the consolidated balance sheet, and the accounting policies of our single operating segment are the same as those described in the Summary of Significant Accounting Policies herein. For additional reportable single operating segment level financial information, see the Consolidated Financial Statements.
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83 ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE. None. ITEM 9A. CONTROLS AND PROCEDURES Evaluation of Disclosure Controls and Procedures The management of NioCorp Developments Ltd. has evaluated, under the supervision and with the participation of our Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”), the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) as of June 30, 2026. Based on that evaluation, the CEO and the CFO have concluded that, as of June 30, 2026, our disclosure controls and procedures were not effective due to a material weakness in internal control over financial reporting described below. Notwithstanding the material weakness in our internal control over financial reporting, our CEO and CFO have concluded that the audited consolidated financial statements included in this Annual Report on Form 10-K fairly present, in all material respects, our financial position, results of operations and cash flows for the periods presented in conformity with U.S. GAAP. The Company’s disclosure controls and procedures have been designed to ensure that: (i) information required to be disclosed by us in reports that we file or submit to the SEC under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in applicable rules and forms and (ii) material information required to be disclosed in our reports filed under the Exchange Act is accumulated and communicated to management, including the CEO and the CFO, as appropriate, to allow for accurate and timely decisions regarding required disclosures. Management does not expect that our disclosure controls and procedures will prevent all errors and all fraud. The effectiveness of our or any system of disclosure controls and procedures, however well designed and operated, can provide only reasonable assurance that the objectives of the system will be met and is subject to certain limitations, including the exercise of judgment in designing, implementing, and evaluating controls and procedures and the assumptions used in identifying the likelihood of future events. Management’s Report on Internal Control over Financial Reporting The management of NioCorp Developments Ltd. is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act for the Company. Management assessed the effectiveness of our internal control over financial reporting as of June 30, 2026. In making this assessment, our management used the criteria set forth in the Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (the “COSO Framework”). Based on that evaluation, the CEO and the CFO have concluded that, as of June 30, 2026, our internal control over financial reporting was not effective due to the material weakness in internal control over financial reporting described below. For a discussion of the previously reported material weaknesses that management has concluded were remediated during fiscal year 2026, see “Remediation of Previously Reported Material Weaknesses” below. Remaining Material Weakness A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim consolidated financial statements will not be prevented or detected on a timely basis. Management concluded that, of the material weaknesses disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended June 30, 2025, one material weakness continued to exist as of June 30, 2026. That material weakness relates to a deficiency in the principles associated with the control activities component of internal control, based on the criteria established by the COSO Framework: • Control Activities: Management did not maintain effective controls over the design and implementation of process-level control activities related to vendor banking information. The remaining material weakness described above could result in a misstatement of account balances or disclosures that would result in a material misstatement to the annual or interim consolidated financial statements that would not be prevented or timely detected. The remaining material weakness did not result in any misstatement of the Company’s consolidated financial statements.
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84 Remediation of Previously Reported Material Weaknesses During fiscal year 2026, management, with oversight from the Audit Committee, completed and tested a series of remediation actions directed at the material weaknesses previously reported in the control environment, risk assessment, control activities and monitoring activities components of internal control. The actions completed include the following: • Control environment - We added two positions to the accounting and financial reporting function, including a VP of Accounting and Senior Accountant. We also engaged outside accounting and internal control consultants with relevant expertise to supplement internal resources. • Risk assessment - We designed and implemented a formal financial reporting risk assessment process requiring periodic review and updating of current risks, internal controls and financial reporting risks, including risks arising from changes in the Company’s business practices and from complex or non-routine transactions. The results of the risk assessment are reviewed with management and communicated to the Audit Committee quarterly. • Control activities - We designed and implemented controls over the monitoring and assessment of the work of third-party specialists, including a documented evaluation of the specialist’s scope of work, competence and objectivity, the completeness and accuracy of the data provided to the specialist, and the appropriateness of the resulting accounting conclusions, and over the evaluation of inputs and assumptions used to estimate the fair value of instruments and features associated with complex debt and equity transactions, including independent review and approval of key assumptions prior to recording. • Monitoring activities - We designed and implemented a monitoring program under which management performs ongoing and separate evaluations to ascertain whether the components of internal control are present and functioning, retains contemporaneous evidence of the performance of key controls, and evaluates and communicates internal control deficiencies, together with an assessment of their severity, in a timely manner to those parties responsible for taking corrective action, including senior management and the Audit Committee. Management tested the design and operating effectiveness of the remediated controls during the year ended June 30, 2026, using sample sizes commensurate with the frequency of each control. Based on that testing, management determined that the remediated controls were appropriately designed and implemented and operated effectively for a sufficient period of time. Accordingly, management concluded that the material weaknesses in the control environment, risk assessment and monitoring activities components of internal control, and the material weaknesses in the control activities component relating to (i) monitoring and assessing the work of third-party specialists, including the evaluation of the appropriateness of accounting conclusions, and (ii) the evaluation of certain inputs and assumptions used to estimate the fair value of instruments and features associated with complex debt and equity transactions, were remediated as of June 30, 2026. Remediation Plan To address the remaining material weakness existing as of June 30, 2026 described above, we are continuing to implement a remediation plan. These actions include the following: • We have designed and implemented process-level controls over the initiation, verification, approval and recording of changes to vendor banking information, including independent verification of each change request through a call-back or comparable out-of- band confirmation to a previously validated contact, segregation of duties between the requestor and the approver of changes to vendor data, and periodic management review of a system-generated report of all changes to vendor master data. The process of designing and maintaining effective internal control over financial reporting is a continuous effort that requires management to anticipate and react to changes in our business, economic and regulatory environments and to expend significant resources. As we continue to evaluate our internal control over financial reporting, we may take additional actions to remediate the material weakness or modify the remediation actions described above. While we continue to devote significant time and attention to these remediation efforts, the remaining material weakness will not be considered remediated until the controls operate for a sufficient period of time, and management has concluded, through testing, that these controls are effective. Management currently expects to complete these actions during fiscal year 2027.
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85 Changes in Internal Control over Financial Reporting Other than the remediation of previously disclosed material weaknesses as discussed above, there has been no change in our internal control over financial reporting during the quarter ended June 30, 2026, that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting. ITEM 9B. OTHER INFORMATION During the quarter ended June 30, 2026, no director or officer (as defined in Rule 16a-1(f) promulgated under the Exchange Act) of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement” (as each term is defined in Item 408 of Regulation S-K). ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTION Not applicable.
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86 PART III ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE Directors and Executive Officers The following table sets forth as of September 25, 2026, the names and ages of, and position or positions held by, our executive officers and directors, the employment background of these persons, and any directorships held by the current directors during the last five years. Name Age Position Date of Appointment Mark A. Smith 67 Chief Executive Officer, President, Executive Chairman, and Director Chief Executive Officer and Director: September 23, 2013 President and Executive Chairman: May 31, 2015 Neal Shah 52 Chief Financial Officer and Corporate Secretary Chief Financial Officer: July 1, 2016 Corporate Secretary: December 3, 2021 Scott Honan 55 Chief Operating Officer May 6, 2014 Jim Sims 65 Chief Communications Officer November 2, 2015 Ernest Cleave 56 Senior Vice President of Business Development August 15, 2025 Anthony W. Fulton 53 Director August 9, 2025 Nilsa Guerrero-Mahon 65 Director September 28, 2017 Dean C. Kehler 69 Director March 17, 2023 Michael G. Maselli 66 Director March 17, 2023 Peter Oliver 63 Director May 25, 2022 The following sets forth a brief description of the business experience of each executive officer and director of the Company, including current directorships and directorships held in, at least, the past five years for each director: Mark A. Smith – Chief Executive Officer, President, Executive Chairman, and Director Mr. Smith has over 44 years of experience in operating, developing, and financing mining and strategic materials projects in the Americas and abroad. In September 2013, he was appointed CEO and a Director of NioCorp. From April 2015 to September 2019, Mr. Smith served as the President and Director for Largo Resources Ltd. (“Largo”), a mineral company with an operating property in Brazil and projects in Brazil and Canada. In addition, from April 2015 to October 2018, Mr. Smith also served as the CEO of Largo. Mr. Smith has also served on the board of directors of IBC Advanced Alloys Corp., a leading copper advanced alloys company (“IBC”), since May 2016 and as CEO of IBC since July 2020. From October 2008 through December 2012, Mr. Smith served as President, CEO and Director of Molycorp, where he was instrumentally involved in taking it from a private company to a publicly traded company with a producing mine. From November 2011 through May 2015, he served on the board of directors at Avanti Mining, a mining company (TSX-V: AVT; Avanti Mining changed its name to AlloyCorp in early 2015). From December 2012 through September 2013, he served as the Managing Director of KMSmith LLC, a business strategy and finance advisory firm, where he served as a consultant. Prior to Molycorp, Mr. Smith held numerous engineering, environmental, and legal positions within Unocal Corporation, a former petroleum explorer and marketer (“Unocal”), and later served as the President and CEO of Chevron Mining Inc., a coal and metal mining company and wholly owned subsidiary of Chevron Corporation (“Chevron Mining”). Mr. Smith also served for over seven years as the shareholder representative of Companhia Brasileira Metalúrgica e Mineração, a private company that currently produces approximately 85% of the world supply of niobium. During his tenure with Chevron Mining, Mr. Smith was responsible for Chevron Mining’s three coal mines, one molybdenum mine, a petroleum coke calcining operation and Molycorp’s Mountain Pass mine. At Unocal, he served as the Vice-President from June 2000 to April 2006, and managed the real estate, remediation, mining and carbon divisions. Mr. Smith is a Registered Professional Engineer and serves as an active member of the State Bars of California and Colorado. He received his Bachelor of Science degree in Agricultural Engineering from Colorado State University in 1981 and his Juris Doctor, cum laude, from Western State University, College of Law, in 1990.
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87 Neal Shah – Chief Financial Officer and Corporate Secretary Mr. Shah joined NioCorp in September 2014 as Vice President of Finance, and now serves as the Company’s CFO and Corporate Secretary. Mr. Shah served as Finance Manager at Covidien Ltd., a medical device company since acquired by Medtronic, from May 2014 through September 2014. From April 2011 until May 2014, he held the positions of Senior Manager of Corporate Development and M&A and more recently the Director of Strategy and Business Planning at Molycorp. Mr. Shah graduated from the University of Colorado with a BSc in Mechanical Engineering in 1996, and from Purdue University with an MBA in 2002. Since the completion of his MBA, Mr. Shah also held key finance roles with Intel Corporation and IBM. Scott Honan – Chief Operating Officer Mr. Honan joined NioCorp in May 2014 as Vice President, Business Development, and since July 2020, has served as the Company’s Chief Operating Officer (“COO”). He also serves as President of Elk Creek Resources Corporation, the NioCorp subsidiary that is developing the Elk Creek Project in Nebraska. Prior to his work at NioCorp, Mr. Honan served in several leadership capacities at Molycorp from February 2001 until May 2014, including as Vice President/Director Health, Environment, Safety and Sustainability and General Manager and Environmental Manager from July 2011 to May 2014. With over 32 years of experience in the gold and rare earth industries, Mr. Honan is a graduate of Queen’s University in Mining Engineering in both Mineral Processing (B.Sc. Honors) and Environmental Management (M.Sc.) disciplines. Jim Sims – Chief Communications Officer Mr. Sims has more than 33 years of experience in devising and executing marketing, media relations, public affairs, and investor relations operations for companies in the mining, chemical, manufacturing, utility, and renewable energy sectors. He joined NioCorp in November 2015 as Vice President, External Affairs, and now serves in a different role for the Company as its Chief Communications Officer, effective June 7, 2022. Prior to NioCorp, Mr. Sims served for more than five years as Director (and then Vice President) of Corporate Communications for Molycorp from March 2010 through November 2015. Since May 2016, Mr. Sims has also served as Director of Investor and Public Relations for IBC. Mr. Sims was President and CEO of Policy Communications, Inc. from 1998 until 2010 and served as White House Director of Communications for the Energy Policy Development Group. A former U.S. Senate Chief of Staff, he is the co-founder and former Executive Director of the Geothermal Energy Association, and he has served as Board Chairman of the Rare Earth Technology Alliance. He is an honors graduate of Georgetown University. Ernest Cleave – Senior Vice President of Business Development Mr. Cleave joined NioCorp in August 2025 as Senior Vice President of Business Development. Mr. Cleave has more than 21 years of experience in the mining, mineral processing, and energy industries. Prior to his work at NioCorp, Mr. Cleave served as the President and CEO of Tinova Resources Corp., a critical minerals exploration company, from June 2024 to August 2025. From September 2013 to June 2024, Mr. Cleave served as the Chief Financial Officer of Largo Inc., a supplier of vanadium and ilmenite products. Additionally, Mr. Cleave served as the Interim President of Largo Clean Energy Corp. (a subsidiary of Largo Inc.) from November 2022 to June 2023. Mr. Cleave’s career has also spanned leadership positions in several other mining and energy companies, including as Chief Financial Officer of Cline Mining, Chief Financial Officer of Petrolympic, Global Lead of Sarbanes-Oxley Compliance at Glencore (previously Falconbridge), and Treasurer and Director of Financial Planning and Analysis at Goldcorp. Mr. Cleave is a Chartered Accountant (AUS & NZL) and is a registered CPA in both Canada and Australia. Mr. Cleave earned his M.B.A. from Deakin University of Victoria, Australia and has undergraduate degrees in computational science and commerce, respectively. Anthony W. Fulton – Director A former Nebraska State Senator and successful business entrepreneur, Mr. Fulton previously served on the Board from 2013 until 2016, when he left to serve as Nebraska Tax Commissioner and Director of the Nebraska Department of Revenue, a 400-employee, $9 billion enterprise from January 2016 to December 2022. A mechanical engineer by training, Mr. Fulton has been the President of the Nevada-based Hallmark Homecare, LLC, an independent domestic caregiver referral agency since May 2023 and is the Founder and Owner of Guardian Angels Homecare, Inc. of Lincoln, Nebraska, an in-home senior care company, where he has served as the President and CEO since March 2003. In addition to his work in the senior care industry, Mr. Fulton serves as the Chairman of the Diocesan Finance Council for the Catholic Diocese of Lincoln (Southern Nebraska) and is the recipient of numerous awards throughout his professional career. He received his B.S. in Mechanical Engineering from the University of Nebraska-Lincoln, with studies in Philosophy at Newman University in Wichita, Kansas and Theology at Mount Saint Mary’s University in Emmitsburg, Maryland.
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88 Nilsa Guerrero-Mahon – Director A former CFO and Controller for global corporations in the technology, energy, and government sectors, Ms. Guerrero-Mahon provides consulting services to domestic and international corporations as the principal at NGM Business Consulting, LLC, a business consulting service, since 2008. In addition, Ms. Guerrero-Mahon was appointed to the board of directors of FinGoal, Inc. in April 2022, a finance technology company building artificial intelligence tools for the financial services industry and other financial technology developers. She also serves as the Chair of the Finance and Audit Committee for the Financial Data Exchange (“FDX”). FDX unifies the financial industry around a common standard for secure and convenient access of permissioned consumer and business financial data. From 2014 to 2019, she served as the Vice Chair of the Board and Chaired the Strategy Committee for the Mountains & North Denver Operating Group, the largest division in the Common Spirit Health System (formerly Centura Health). From 2009 to 2025, Ms. Guerrero- Mahon served as a gubernatorial appointed Board Member of the State of Colorado Securities Commission and the Financial Services Commission. Among other prior positions, from 2004 to 2007, she was the Global Services Controller at Microsoft Corporation, overseeing internal controls, compliance and corporate finance activities. Ms. Guerrero-Mahon stays current with the latest Corporate Governance practices serving as a member of the Nasdaq Center for Board Excellence. She is an NACD Board Leadership Fellow and a member of the SASB Alliance. She holds a CERT Certificate in Cybersecurity Oversight from Carnegie Mellon University. Ms. Guerrero-Mahon is a Certified Public Accountant and a Certified Fraud Examiner. She received an Executive MBA from the Daniels College of Business at the University of Denver, a BS in Business Administration - Accounting from the Interamerican University in San Juan, Puerto Rico, and an AS in Computer Science from the EDP University of Puerto Rico. Peter Oliver – Director With a background in chemistry, Mr. Oliver began working at Greenbushes, Western Australia, for Sons of Gwalia, a mining company, in May 2003. After Sons of Gwalia went into administration in 2004, Mr. Oliver was hired by Talison Lithium Limited (“Talison”), a mining company, where he served as General Manager of Talison’s Greenbushes and Wodgina Mines and as Talison’s COO, until Mr. Oliver was appointed as the CEO/Managing director. As Talison’s CEO/Managing director, Mr. Oliver led the listing of Talison on the Toronto Stock Exchange in September 2010. Mr. Oliver guided Talison through its acquisition in 2013 by Tianqi Lithium Corporation (“Tianqi”). He then served as a corporate adviser to Tianqi, focusing on M&A opportunities and global expansion, including advising on the sale of 49% of Talison to Albemarle Corp. and the acquisition of 24% of Sociedad Quimica y Minera de Chile S.A., as well as significant expansions of Talison’s Greenbushes lithium concentrate production. Mr. Oliver also was a founding member of Tianqi Lithium Energy Australia Pty Ltd, a wholly owned subsidiary of Tianqi, which was established to build a major Lithium Hydroxide manufacturing facility in Western Australia. Until June 2021, Mr. Oliver remained as a director of Talison, a joint venture between Tianqi and Albemarle Corp. In September 2022, Mr. Oliver was appointed to the Board of Latin Resources, a lithium exploration company in Australia. Mr. Oliver was appointed to the role of Executive Director of Latin Resources in 2024 and helped lead the successful acquisition of Latin Resources by Pilbara Minerals LTD (ASX: PLS) in March 2025. Dean C. Kehler – Director Mr. Kehler co-founded Trimaran Fund Management, L.L.C. ("Trimaran Fund") in 1998, where he is a Managing Partner. Mr. Kehler was also the Co-Chairman and Chief Executive Officer of GX Acquisition Corp. II, a position he held from August 2018 to March 2023. From 1995 to 2000, Mr. Kehler held senior positions at Canadian Imperial Bank of Commerce ("CIBC"), including Vice Chairman of CIBC World Markets Corp. Mr. Kehler currently serves on the Board of Directors of BCP Investment Corporation (formerly Portman Ridge Finance Corporation). Within the last five years, he has served as a director of Celularity Inc. and El Pollo Loco Holdings, Inc. He holds a bachelor's degree from the Wharton School of the University of Pennsylvania. Michael G. Maselli – Director Mr. Maselli is a managing director of Trimaran Fund, a position he has held since 2006, and was the President of Acquisitions of GX Acquisition Corp. II from August 2018 to March 2023. Before joining Trimaran Fund in February 2006, Mr. Maselli worked in the Corporate and Leverage Finance Groups of CIBC World Markets. Prior to joining CIBC in 1997, Mr. Maselli served as a Managing Director in Bear Stearns’ corporate finance group and, prior to that, as a Vice President at Kidder Peabody & Co. Incorporated. Mr. Maselli served on the board of directors of El Pollo Loco Holdings from 2010 to 2024, and he served as their Chairman of the Board from 2011 to 2023. He served on the board of ChanceLight, Inc. (f/k/a Educational Services of America, Inc.) until 2018. From 2013 to 2015, he served on the board of directors of Norcraft Companies, Inc., and
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89 also served on the board of managers of its predecessor company beginning in 2003. Additionally, Mr. Maselli served on the board of directors of Standard Steel, LLC, and was director as well as Chairman of the Board of CB Holding Corp. Mr. Maselli received an MBA with distinction from The A.B. Freeman School at Tulane University and a bachelor’s degree in economics from the University of Colorado. Other Directorships The following is a list of directorships held over the past five years by our directors. Except as listed below, no directors of the Company are also directors of reporting issuers. Name of Director Other Reporting Issuer (or equivalent) Exchange Mark A. Smith IBC Advanced Alloys Corp. TSX-V Peter Oliver Latin Resources ASX Dean C. Kehler El Pollo Loco Holdings, Inc. BCP Investment Corporation Celularity Inc. GX Acquisition Corp. II Nasdaq Nasdaq Nasdaq Nasdaq Michael G. Maselli El Pollo Loco Holdings, Inc. Nasdaq Legal Proceedings No director or executive officer of the Company is a party adverse to the Company or any of its subsidiaries or has a material interest adverse to the Company or any of its subsidiaries. During the past ten years, none of the persons serving as executive officers and/or directors of the Company and, with respect to promoters or control persons, for the past five years, none have been the subject matter of any of the legal proceedings that are required to be disclosed pursuant to Item 401(f) of Regulation S-K. Further, no such legal proceedings are believed to be contemplated by governmental authorities against any director or executive officer. Ethical Business Conduct The Board expects management to operate the business of the Company in a manner that enhances shareholder value and is consistent with the highest level of integrity. Management is expected to execute the Company’s business plan and to meet performance goals and objectives according to the highest ethical standards. In addition, directors and senior officers are bound by the provisions of the Company’s Articles and the British Columbia Business Corporations Act (“BCBCA”), which set forth how any conflicts of interest are to be dealt with. In particular, any director who has a material interest in a particular transaction is required to disclose such interest and to refrain from voting with respect to the approval of any such transaction. Insider Trading Policy We have insider trading policies and procedures, as described below, applicable to our directors, officers, and employees, and have implemented processes for the Company, that we believe are reasonably designed to promote compliance with insider trading laws, rules, and regulations, and the Nasdaq listing standards. The Board has adopted an insider trading policy (the “Insider Trading Policy”) to help ensure, among other things: (i) that persons to whom the policy applies understand their obligations to preserve the confidentiality of “Material Nonpublic Information” (as defined in the Insider Trading Policy); (ii) strict compliance by all insiders with all requirements relating to the reporting of insider trading and with respect to trading when in possession of “Material Nonpublic Information”; and (iii) that individuals subject to scheduled and unscheduled blackout periods adhere to the restrictions on trading as set out in the Insider Trading Policy. Code of Business Conduct and Ethics Our Board has adopted a written Code of Business Conduct and Ethics applicable to our employees, officers, and directors, including those officers responsible for financial reporting. The Code of Business Conduct and Ethics is available on our website at www.niocorp.com. If the Board amends the Code of Business Conduct and Ethics or grants a waiver, including an implicit waiver, from the Code of Business Conduct and Ethics, the Company will disclose the information on its internet website. The waiver information will remain on the website for at least 12 months after the initial disclosure of such waiver. Given the current
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90 size of the Company workforce, and the lack of significant operations, the Board monitors compliance through periodic discussions with executive management. Audit Committee and Audit Committee Financial Experts Our Audit Committee is currently comprised of Nilsa Guerrero-Mahon, as Chair, Dean Kehler, and Michael Maselli, all of whom are independent directors. Our Board has determined that each of the three members are audit committee financial experts, as defined by the rules of the SEC. Further, all Audit Committee members are financially literate as defined in NI 52-110. The Audit Committee was established in accordance with Section 3(a)(58)(A) of the Exchange Act. Delinquent Section 16(a) Reports Section 16(a) of the Exchange Act requires the Company’s officers and directors, and persons who own more than ten percent of a registered class of the Company’s equity securities, to file reports of ownership and changes in ownership of such securities with the SEC. Based upon the review of the copies of Section 16(a) forms received by the Company, and upon written representations from reporting persons concerning the necessity of filing a Form 5 Annual Statement of Changes in Beneficial Ownership, the Company believes that, during fiscal 2026, all required reports were filed on a timely basis, other than the filing of a Form 3 and a Form 4 for each of Mr. Fulton and Mr. Cleave, which were filed late because of delays in processing of Form IDs due to new EDGAR Next requirements. The Form 4s each reported a single transaction on August 18, 2025.
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91 ITEM 11. EXECUTIVE COMPENSATION Unless otherwise indicated, all compensation amounts in this Item 11 are presented in whole dollars. The following table sets out the compensation for the fiscal years ended June 30, 2026 and 2025 for the individual who served as the Company’s CEO during fiscal year 2026, as well as the Company’s two other most highly compensated executive officers other than the CEO who were serving at the end of the last fiscal year (collectively, the “named executive officers” or "NEOs"): Fiscal 2026 Summary Compensation Table Name and Principal Position Fiscal Year Salary ($) Bonus (1) ($) Option Awards (2) ($) All Other Compensation (3) ($) Total ($) Mark A. Smith, Chief Executive Officer, President, Executive Chairman, and Director (4) 2026 $ 355,625 $ 712,784 $ 1,027,500 $ — $ 2,095,909 2025 325,000 — 126,000 — 451,000 Scott Honan, Chief Operating Officer 2026 297,500 453,197 685,000 6,000 1,441,697 2025 280,000 — 84,000 — 364,000 Neal Shah, Chief Financial Officer and Corporate Secretary 2026 271,875 420,621 685,000 5,500 1,382,996 2025 250,000 — 84,000 — 334,000 (1) The amounts in this column for fiscal 2026 include the payouts to the named executive officers under the 2026 AIP (defined below) and special recognition bonus amounts approved by the Board in August 2025, each as discussed below. (2) Reflects the grant date fair value of the Options granted during the reported fiscal years. Fiscal year 2026 grants consisted of 375,000 Options for Mr. Smith and 250,000 Options for each of Messrs. Honan and Shah, in each case at an exercise price of $4.35 per share. Grant date fair values were computed in accordance with Financial Accounting Standards Board Accounting Standards Codification ("FASB ASC") Topic 718. Assumptions used in the calculation of these amounts are described in Note 9b in the Company’s consolidated financial statements included in this Annual Report on Form 10-K. These Options were vested 34% on the grant date (August 18, 2025) and an additional 33% of the Options will vest on each of the first two anniversaries of the grant date. These Options generally remain exercisable until the fifth anniversary of the grant date. (3) The fiscal year 2026 row includes the Company’s matching contributions made under the Company’s 401(k) Retirement Savings Plan, which are provided to eligible participants in accordance with the terms of the plan. (4) Disclosed amounts were paid to 76 Resources, LLC, an entity controlled by Mr. Smith, as further described below under “Employment Agreements and Severance Arrangements.” Narrative Disclosure to Summary Compensation Table Compensation Governance The Company’s Compensation and Organization Committee of the Board (the “Compensation Committee”) generally determines the amount of compensation for the Company’s executives, which is designed to reflect the need to provide incentives and compensation for the time and effort expended by the executives while taking into account the financial and other resources of the Company. The Compensation Committee has the authority to engage and compensate, at the expense of the Company, any outside advisor that it determines to be necessary to permit it to carry out its duties (including compensation consultants and advisors). In fiscal 2026, the Compensation Committee engaged Semler Brossy Consulting Group, LLC (“Semler Brossy”) as its independent compensation consultant. Semler Brossy was retained to assist the Compensation Committee in developing an executive compensation peer group and market compensation comparisons and in designing a Company-wide annual incentive program. Semler Brossy reports directly to the Compensation Committee, which has the sole authority to retain, terminate and approve the fees of its compensation consultant. Semler Brossy provided no services to the Company during fiscal 2026 other than those provided at the direction of the Compensation Committee. The Compensation Committee has assessed the independence of Semler Brossy as required under Nasdaq listing rules. Based on this review, the Compensation Committee has determined that Semler Brossy's work has not raised any conflict of interest.
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92 The Compensation Committee has reviewed the Company’s compensation policies and practices and does not believe that they create any risks that are reasonably likely to have a material adverse effect on the Company. Compensation Program Design The Board, in conjunction with the Compensation Committee, determines compensation and rewards to senior management on the basis of individual and corporate performance, both in the short term and the long term, while at the same time being mindful of the responsibility that the Company has to its shareholders. The Compensation Committee believes that the Company’s compensation program should remain straightforward in design, consistent with the Company’s current stage of development, and that it should balance reasonable current compensation against longer-term compensation tied to the performance of the Company as a whole. As described under “Changes for Fiscal 2027” below, the Compensation Committee took a number of steps during fiscal 2026 to formalize the program while preserving that design philosophy. Fiscal Year 2026 Actions Historically, the Compensation Committee had not established a formal set of benchmarks or performance criteria to be met by the Company’s named executive officers; rather, the members of the Compensation Committee used their own subjective assessments of the level of success of the Company to determine, collectively, whether or not the named executive officers had successfully achieved the Company’s business plan and strategy and the degree to which they performed in that regard. The Compensation Committee also had not established any pre-determined formula for determining named executive officer compensation, either as to the amount thereof or the specific mix of compensation elements. Instead, compensation (and adjustments from time to time) was set through discussions and subjective assessments at the Compensation Committee level. Compensation decisions for fiscal 2026 outlined below generally reflect this historical approach; that said, the Compensation Committee took steps in fiscal 2026 to adopt a more formal market analysis and pay determination process. Beginning in fiscal 2027, the Compensation Committee intends to consider its own subjective assessments of Company and individual performance alongside a formal set of market assessments and pre-set performance objectives – see “Changes for Fiscal 2027” below for additional detail. Salaries The Compensation Committee sets base salaries (or, for Mr. Smith, base consulting fees) for the Company’s named executive officers generally at a level it deems appropriate to attract and retain capable individuals while taking into account the total compensation provided to each individual. Each year, the Compensation Committee determines if adjustments are appropriate based upon executive performance, role scope, and market context. No changes were made to any executive’s annualized salary for fiscal 2025 compared to fiscal 2024. For fiscal 2026, the Compensation Committee determined to make a number of adjustments in consideration of Company and individual performance, as well as competitive market dynamics: Executive Fiscal Year 2025 Salary Rate Fiscal Year 2026 Salary Rate % Increase Fiscal Year 2026 Actual Salary Mark A. Smith Chief Executive Officer, President, Executive Chairman, and Director $325,000 $360,000 10.8 $355,625 Scott Honan Chief Operating Officer 280,000 300,000 7.1 297,500 Neal Shah Chief Financial Officer and Corporate Secretary 250,000 275,000 10.0 271,875 Amounts shown as salary rates represent annualized base salary rates and not amounts actually earned. The fiscal 2026 increases were effective August 15, 2025, and the amounts actually earned during fiscal 2026 are reported in the Summary Compensation Table. Amounts shown for Mr. Smith represent base consulting fees payable under his consulting arrangement rather than base salary. Annual Incentive Plan In fiscal 2026, the Compensation Committee designed and adopted the Company’s annual incentive plan (“AIP”), which is intended to operate as a Company-wide, performance-based, annual cash incentive award program in which substantially all of the Company’s and its subsidiaries’ regular full-time employees participate, including each of the Company’s named executive officers. Annual AIP award opportunities are established generally by employee role considerations, so that annual
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93 AIP award opportunities are generally based on the scope of an employee’s role on a consistent, Company-wide basis rather than negotiated individually. The Company adopted the AIP to help attract, motivate, and retain employees at all levels and to align the interests of its workforce, including senior management, with the long-term interests of the Company’s shareholders. In general, under the AIP, each participant has a target annual incentive award opportunity expressed as a percentage of base salary, with award payouts generally ranging from 0% to 200% of target based on performance against pre-established measures. The AIP was adopted during late fiscal 2026 and was applied to fiscal 2026 on a transitional basis. Beginning in fiscal 2027, the AIP operates on a full fiscal-year basis, with performance measures and individual objectives established at or near the beginning of each fiscal year — see “Changes for Fiscal 2027” below for additional detail. For fiscal 2026, performance for all eligible employees was weighted: 45% on the achievement of pre-established, Board-approved corporate milestones tied to project development, financing, and execution readiness; 10% on safety performance, measured by reference to the presence or absence of lost-time incidents and OSHA-reportable incidents; and 45% on individual performance. Because the AIP was adopted during late fiscal 2026, individual performance for fiscal 2026 was assessed on a qualitative basis rather than against pre-established individual objectives. Beginning in fiscal 2027, individual objectives will be established at or near the beginning of each performance period. The Board evaluates the performance of the Chief Executive Officer, and the Chief Executive Officer evaluates the performance of the other named executive officers. Annual incentive awards under the AIP, if any, are generally payable in cash following the end of the applicable fiscal year, subject to the participant’s continued service through the payment date and the other terms of the AIP. For fiscal 2026, target award opportunities were applied to each named executive officer’s eligible earnings for the fiscal year rather than to his annualized base salary rate. The Compensation Committee determined that the following amounts were payable under the AIP to the named executive officers: Executive Eligible Earnings Target (% of Eligible Earnings) Target Award Achievement (% of Target) Payout Mark A. Smith Chief Executive Officer, President, Executive Chairman, and Director $355,625 100% $355,625 169.5 $602,784 Scott Honan Chief Operating Officer $297,500 75% $223,125 169.5 $378,197 Neal Shah Chief Financial Officer and Corporate Secretary $271,875 75% $203,906 169.5 $345,621 The Compensation Committee determined the achievement levels above based on the following performance assessment: Corporate Milestones (45% weighting, 161.1% achievement percentage) • Advancement of the drilling program in support of future mineral reserve estimation • Substantial progress toward completion of the feasibility study, notwithstanding laboratory processing bottlenecks • Advancement of land parcel acquisition for surface and/or mineral rights • Capital raises substantially above expectations, positioning the Company advantageously for its broader project financing objectives Safety Performance (10% of final payout is fully achieved) • No lost-time incidents and no OSHA-reportable incidents were recorded in fiscal 2026, measured on a quarterly basis. A strong safety culture was maintained throughout site drilling operations and the transition to construction of the project portal. • The Compensation Committee structured the safety measure so that safety performance, when fully achieved, would be set at an amount that would represent approximately 10% of the final total annual incentive award payout. Safety is assessed quarterly, and one-quarter of the component is earned for each quarter in which no lost-time or OSHA-reportable incident occurs. All four quarters qualified in fiscal 2026, and the component was therefore earned in full.
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94 Individual Performance (45% weighting, 177.8% achievement percentage) • Individual objectives were not pre-established for fiscal 2026 because the AIP was adopted during late fiscal year 2026. The Compensation Committee assessed this component qualitatively and determined that the named executive officers performed effectively as a team in delivering the corporate results described above and in establishing recommendations regarding the AIP framework and related compensation governance enhancements. A consistent achievement level was applied across the named executive officers. At the Board’s direction, specific individual objectives will be established for each named executive officer for fiscal 2027 at the beginning of fiscal 2027. Aggregate Achievement – Applying the weightings above, the corporate milestone and individual performance components contributed 72.5 and 80.0 percentage points, respectively, and the safety component contributed 17.0 percentage points (so that it would represent approximately 10% of the final payout), resulting in an overall achievement of 169.5% for fiscal 2026. Bonus Compensation The Compensation Committee has discretion, where deemed appropriate and financially affordable for the Company, to grant a cash bonus to a named executive officer based on the performance of both the individual named executive officer and the Company. In early fiscal 2026, the Board approved special cash bonuses for each of the named executive officers, in the amount of $110,000 for Mr. Smith, $75,000 for Mr. Honan, and $75,000 for Mr. Shah. These bonuses were approved generally in recognition of the named executive officers’ performance. Long-Term Incentives The incentive portion of each named executive officer’s compensation package consists primarily of Options awarded under the 2017 Amended Long-Term Incentive Plan. Share ownership opportunities through the grant of Options are provided to align the interests of senior management of the Company with the longer-term interests of the shareholders of the Company. The Compensation Committee reviews the overall number of Options held by an individual (including the exercise prices and remaining terms of outstanding Options and whether previously granted Options have expired out of the money or were exercised) and takes such information into consideration when reviewing proposed new grants. After considering the Chief Executive Officer’s recommendations, if any, and the foregoing factors, the resulting proposed Option grant is submitted to the Board for final approval. During the fiscal year ended June 30, 2026, the Board, upon the recommendation of the Compensation Committee, approved the grant of Options proposed by management, and the named executive officers were granted the following number of Options effective August 18, 2025, each with an exercise price of $4.35 per share: Mr. Smith, 375,000 Options; Mr. Honan, 250,000 Options; and Mr. Shah, 250,000 Options. Options vest in three installments: 34% on the grant date, 33% on the first anniversary of the grant date, and 33% on the second anniversary of the grant date. The Options expire five years after the grant date, subject to earlier expiration upon a cessation of service. Option grants made in fiscal 2026 were awarded primarily in recognition of overall Company and individual performance as described above and to align executives' interests with the future performance of the Company. In response to shareholder feedback and the Compensation Committee’s market assessment conducted in fiscal 2026, equity awards granted beginning in fiscal 2027 will be determined (i) based on long-term incentive target grant values set in consideration of both internal Company context and market data from the Company’s compensation peer group, and (ii) in the form of awards that may vest ratably over three years from the date of the grant – see “Changes for Fiscal 2027” below for additional detail. Changes for Fiscal 2027 With the assistance of Semler Brossy, the Compensation Committee established an executive compensation peer group and conducted a thorough market review of executive pay levels, compensation designs, and governance practices, and adopted a number of program enhancements to better align the Company’s programs with market practice and respond to feedback from our shareholders. Compensation Peer Group The Compensation Committee selected the peer group from U.S.- and Canada-listed mining and mineral development companies that are comparable to NioCorp in industry, stage of development, and scale of operations, with an emphasis on
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95 companies advancing large-scale critical minerals or precious metals projects that have not yet reached commercial production. Because the Company is pre-revenue and operates with a small corporate workforce, the Compensation Committee focused on factors it believes most directly affect the Company's ability to attract and retain executive talent — as such, the review emphasized project development, employee headcount, and geographic footprint in addition to giving consideration to financial metrics such as revenue. The Compensation Committee uses the peer group as one reference point among several in evaluating the competitiveness of executive pay, and does not target compensation at any specific percentile of the peer group. The peer group includes the following companies: •American Battery Technology Company• Dakota Gold Corp. • Idaho Strategic Resources Inc. •Centerra Gold Inc. • enCore Energy Corp • Perpetua Resources Corp. •Compass Minerals International, Inc.• Hycroft Mining Holding Corporation• United States Antimony Corporation •Contango Silver & Gold Inc. • i-80 Gold Corp. • Ucore Rare Metals Inc. Annual Incentive Plan As discussed above, the Company adopted the AIP during fiscal 2026 as a formal cash-based annual incentive plan. Beginning in fiscal 2027, the AIP will operate on a full fiscal-year basis, with performance measures established at the beginning of each fiscal year, in order to strengthen the pay-for-performance character of the Company’s compensation programs and to tie executive compensation outcomes more directly to accomplishments in the interests of shareholders. Key aspects of the program include: • Target award opportunities for each named executive officer expressed as a percentage of base salary, with a potential payout range from 0% to 200% of target based on performance; • Performance measured against a mixture of financial, strategic, and operational goals determined by the Compensation Committee and established at the beginning of each fiscal year; and • Specific individual performance objectives established for each named executive officer at the beginning of each fiscal year. Long-Term Incentives For fiscal 2027, the Compensation Committee has established annual long-term incentive target grant values for each named executive officer based on market data. To better align the interests of executives with those of shareholders and support retention, long- term incentive awards for fiscal 2027 are expected to consist of stock options that vest ratably over a two-year period. Based on shareholder feedback, the Compensation Committee also evaluated the feasibility of introducing performance-based equity for future executive long-term incentive awards. The Compensation Committee ultimately determined not to adopt performance-based equity at this time as (i) the Company’s current stage of development makes it difficult to establish meaningful multi-year performance goals, and (ii) the Company’s equity awards are made in the form of stock options, which deliver value only to the extent the Company’s share price appreciates following the grant date and therefore provide inherent performance alignment. That said, the Compensation Committee intends to periodically revisit and assess the feasibility of adopting performance-based equity in future years. Stock Ownership Guidelines The Company adopted formal stock ownership guidelines for its executive officers and independent directors during fiscal 2026, effective June 26, 2026. Under the guidelines, each covered executive officer or director is required to hold shares of the Company’s common stock with a value equal to a multiple of his or her base salary (6.0x for the Chief Executive Officer and 3.0x for the other named executive officers) or annual cash retainer (5.0x for independent directors). Each covered individual has five years from the later of the date the guidelines were adopted and the date on which he or she first becomes subject to the guidelines to satisfy the applicable requirement.
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96 Employment Agreements and Severance Arrangements Agreement Regarding Mr. Smith The Company is currently a party to a Consulting Agreement with 76 Resources, LLC (an entity controlled by Mr. Smith) under which (as currently in effect, the “Smith Agreement”) 76 Resources, LLC, through Mr. Smith, performs the duties and responsibilities of the CEO of the Company and related services, for an indefinite term at a base rate of $360,000 per year as of June 30, 2026, generally payable in equal semi-monthly installments of $15,000. Any bonuses and incentive payments are payable at the discretion of the Board. Mr. Smith is eligible to receive Options under the 2017 Amended Long-Term Incentive Plan, as determined by the Board. The Company may terminate the Smith Agreement at any time without notice or payment if (1) 76 Resources, LLC commits a material breach of the Smith Agreement (subject to a cure period in certain circumstances), (2) Mr. Smith dies or becomes permanently disabled, or (3) certain other “for cause” scenarios occur (as further described in the Smith Agreement). In the event the Smith Agreement is terminated by the Company for any other reason or if 76 Resources, LLC terminates the Smith Agreement on the occurrence of a Triggering Event, the Company shall pay 76 Resources, LLC a lump sum termination fee equal to the base fee in effect at the termination date as well as the average of any annual bonuses or other cash incentive payments for two calendar years immediately preceding the year the termination occurs. A Triggering Event is defined as: a substantial change in the nature of services to be performed by 76 Resources, LLC; a material breach by the Company of the Smith Agreement that is not remedied within 30 days of notice; the cessation of the Company as a going concern; the failure of the Company to pay a material amount due pursuant to the Smith Agreement within 30 days of the due date; or a material reduction in base fee or any other form of compensation payable by the Company to 76 Resources, LLC, except where all senior executives or consultants of the Company are subject to relatively similar reductions in such values. 76 Resources, LLC may terminate the Smith Agreement for a reason other than a Triggering Event on 90 days’ written notice and, should the Company immediately accept such termination notice, it shall pay 76 Resources, LLC the sum of $69,904. Should a change of control of the Company occur (as that term is defined in the Smith Agreement) and, within one year, either a Triggering Event occurs and 76 Resources, LLC terminates the Smith Agreement or 76 Resources, LLC’s engagement is terminated by the Company under circumstances that would give rise to a termination payment in the absence of a change of control, then 76 Resources, LLC shall be entitled to receive an amount equal to the base fee in effect at the termination date as well as the average of any annual bonuses or other cash payments for two calendar years immediately preceding the year the termination occurs. In the event 76 Resources, LLC is entitled to a termination payment with respect to a change of control, any Options previously granted to Mr. Smith shall become fully vested and shall remain exercisable for the original term of grant despite a termination of the services of 76 Resources, LLC. Termination payments under the Smith Agreement are generally contingent on a release of claims by 76 Resources, LLC. The Smith Agreement also includes customary confidentiality and six- month employee non-solicitation provisions. If the Smith Agreement had been terminated by the Company for any reason other than as set out in the Smith Agreement, if 76 Resources, LLC terminated the Smith Agreement on the occurrence of a Triggering Event, or had a change of control of the Company occurred and within one year, either a Triggering Event occurred and 76 Resources, LLC terminated the Smith Agreement or 76 Resources, LLC’s engagement was terminated by the Company without the occurrence of a Triggering Event for any reason other than as set out in the Smith Agreement, effective as of June 30, 2026, 76 Resources, LLC (as ultimate successor in interest to KMSmith, LLC) would have been entitled to a payment of $415,000. Agreements Regarding Messrs. Shah and Honan As previously disclosed, on September 25, 2022, in connection with our entry into the Business Combination Agreement, Messrs. Shah and Honan (the “Covered Officers”) entered into employment agreements with a U.S. affiliate (the “U.S. Affiliate”) of the Company (the “Employment Agreements”). The Employment Agreements became effective as of March 17, 2023, and will continue until either the Covered Officer or the U.S. Affiliate terminates the Covered Officer’s employment for any reason. Pursuant to the Employment Agreements, Mr. Shah continues to serve as CFO of the Company, and Mr. Honan continues to serve as the COO of the Company and serves as President of the U.S. Affiliate. The Employment Agreement for Mr. Shah provided for an initial annual base salary of $220,000 per year, and Mr. Honan’s Employment Agreement provided for an initial annual base salary of $260,000 per year. The annual base salary rates for the Covered Officers are reviewed at least annually for potential increases. The base salary rates of Messrs. Shah and Honan were increased in fiscal 2023 to $250,000 for Mr. Shah and $280,000 for Mr. Honan. There were no increases in base salary rates for fiscal 2024 or 2025. In fiscal 2026, Mr. Shah's base salary rate increased to $275,000 per year and Mr. Honan's base salary rate increased to $300,000 per year. The Employment Agreements also provide each of the Covered Officers with eligibility to participate in (1) any annual cash bonus plan and/or any long-term incentive compensation plan as may be established by the U.S. Affiliate or its affiliates, and (2) any employee benefit plan, program, or policy of the U.S. Affiliate or its affiliates as may
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97 be in effect for senior executives of the U.S. Affiliate or its affiliates generally. The Employment Agreements also include the following additional features: (1) severance benefits upon certain qualifying terminations of employment, consisting of: (a) for a qualifying termination of the Covered Officer’s employment by the U.S. Affiliate without Cause (as such term is defined in the Employment Agreements) that does not occur within two years after a Change in Control of the U.S. Affiliate (as defined in the Employment Agreements), certain accrued obligations, plus 12 months of salary continuation, and (b) for a qualifying termination of the Covered Officer’s employment by the U.S. Affiliate without Cause or by the Covered Officer for Good Reason (as such term is defined in the Employment Agreements) that occurs within two years after a Change in Control (a “Change in Control Termination”), certain accrued obligations, and a lump sum cash amount equal to two times the Covered Officer’s annual base salary as in effect at the time of such termination; and (2) a requirement that each Covered Officer execute a customary release of claims in favor of the U.S. Affiliate to receive severance compensation. In connection with the Covered Officers entering into the Employment Agreements each Covered Officer also entered into a restrictive covenant agreement (a “Restrictive Covenant Agreement”). The Restrictive Covenant Agreements include customary restrictive covenants, including non-competition and non-solicitation obligations that remain in effect both during the employment term and for one year following termination of the Covered Officer’s employment other than a Change in Control Termination (in which case the period will be two years following such Change in Control Termination), as well as other customary restrictive covenants, such as confidentiality provisions. Stock Options Under the 2017 Amended Long-Term Incentive Plan In accordance with the 2017 Amended Long-Term Incentive Plan, the Company granted Options to its named executive officers during the Company’s 2026 fiscal year; no other equity-based awards were granted to the named executive officers during the 2026 fiscal year. The following table sets forth the outstanding equity awards for each named executive officer at June 30, 2026. The Company has not granted full value stock-based awards to any of its named executive officers. Outstanding Equity Awards at 2026 Fiscal Year-End Option Awards Name Grant Date (1) Number of Securities Underlying Unexercised Options (#) Exercisable Number of Securities Underlying Unexercised Options (#) Unexercisable Option Exercise Price ($) Option Expiration Date Mark A. Smith 02/15/2024 375,000 — 2.99 02/15/2029 12/23/2024 150,000 — 1.40 12/21/2029 8/18/2025 127,500 247,500 4.35 8/19/2030 Scott Honan 02/15/2024 250,000 — 2.99 02/15/2029 12/23/2024 100,000 — 1.40 12/21/2029 8/18/2025 85,000 165,000 4.35 8/19/2030 Neal Shah 02/15/2024 250,000 — 2.99 02/15/2029 12/23/2024 100,000 — 1.40 12/21/2029 8/18/2025 85,000 165,000 4.35 8/19/2030 (1) The Options granted on August 18, 2025 vested 34% at grant, and will vest 33% on each of August 18, 2026 and August 18, 2027. Retirement Plan Benefits Messrs. Honan and Shah are each eligible to participate in the Company’s 401(k) savings plan on the same basis as our other eligible employees. The 401(k) savings plan is designed to reward continued employment with the Company and assist participants with financial preparation for retirement. Participants can defer a portion of their eligible compensation under the plan, subject to Code limits. Beginning January 1, 2026, the Company began providing matching contributions to the 401(k) savings plan. Matching contributions equal 100% of the participant’s contributions up to 4% of eligible compensation and vest immediately.
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98 Termination and Change of Control Benefits Except as described above, the Company is not a party to any plans or arrangements regarding the named executive officers under which they may receive enhanced or incremental compensation or benefits in the event of a change of control, termination of employment (as a result of resignation, retirement, change of control, etc.) or a change in responsibilities following a change of control. Options are generally subject to clawback provisions, and provide for post-employment exercise periods, pursuant to the terms of such awards and the 2017 Amended Long-Term Incentive Plan. Practices Related to the Grant of Equity Awards Under our policies and practices, the approval of Options (including any Option grants to our named executive officers and directors) is typically provided at a Board or Compensation Committee meeting or via unanimous written action on the part of the Board or Compensation Committee. In the past, such grants were not generally made on any kind of predetermined, regular schedule. Instead, our award recipients (including the named executive officers and directors) generally received annual grants at various times each year, including as recommended by the CEO to the Board or Compensation Committee. Board or Compensation Committee meetings or written actions to approve such grants were scheduled on an ad hoc, as-needed basis, generally prompted by a determination by the Board or Compensation Committee that such grants should be made (or a request by management or the Board that such grants be made). Going forward, it is the Company's intention that equity award grants will generally be made on a predetermined annual cycle in connection with the Compensation Committee's annual compensation review. Including for grants made during fiscal year 2026, we do not time the disclosure of material non-public information for purposes of affecting the value of executive compensation, and we do not make any grants while in the possession of material non-public information. During fiscal year 2026, we did not grant Options (or similar awards) to any of our named executive officers during the period beginning four business days before and ending one business day after the filing of any Company periodic report on Form 10-Q or Form 10-K, or the filing or furnishing of any Company Form 8-K, that disclosed any material non-public information. Fiscal 2026 Director Compensation One of the directors serving on the Board (Mr. Smith) is also a named executive officer. For a description of the compensation paid to Mr. Smith, see “Fiscal 2026 Summary Compensation Table” and the accompanying narrative provided above. The following table sets forth all compensation the Company granted to our directors, other than Mr. Smith, for the fiscal year ended June 30, 2026: Name Fees Earned or Paid in Cash ($) Option Awards ($)(1) All Other Compensation ($) Total ($) Peter Oliver $40,000 $164,400 $— $204,400 Nilsa Guerrero-Mahon 40,000 150,700 — 190,700 David C. Beling (2) 35,000 137,000 — 172,000 Dean C. Kehler 35,000 137,000 — 172,000 Michael G. Maselli 35,000 137,000 — 172,000 Anthony W. Fulton (3) — 137,000 — 137,000 Michael J. Morris (4) — — — — (1) Reflects the grant date fair value of Options granted during the 2026 fiscal year, consisting of 60,000 Options for Mr. Oliver, 55,000 Options for Ms. Guerrero-Mahon, and 50,000 Options each for Messrs. Beling, Kehler, Maselli, and Fulton, in each case at an exercise price of $4.35 per share, computed in accordance with FASB ASC Topic 718. Assumptions used in the calculation of these amounts are described in Note 9b in the Company’s consolidated financial statements included in this Annual Report on Form 10-K. These Options were vested 34% on the grant date (August 18, 2025) and an additional 33% of the Options will vest on each of the first two anniversaries of the grant date. These Options generally remain exercisable until the fifth anniversary of the grant date. The narrative below discloses the number of stock awards and option awards held by each of the directors listed in the table as of the end of fiscal year 2026. (2) Mr. Beling did not stand for re-election at our annual general meeting of shareholders held on April 6, 2026. (3) Mr. Fulton was appointed to the Board on August 9, 2025.
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99 (4) Mr. Morris served on the Board until his death on July 20, 2025. In the past, the non-employee directors of the Company have had no standard compensation arrangements, or any other arrangements, with the Company, except as herein disclosed. Option grants were determined by the Board or Compensation Committee on a discretionary basis each year, and the non-employee directors did not receive any cash fees for serving on the Board. In fiscal 2026, however, each non-employee director serving on August 13, 2025, was granted a modest cash award in recognition of their service, the value of which is reflected in the "Fiscal 2026 Director Compensation" table above. Commencing with the 2027 fiscal year, non-employee directors are eligible for a more standardized compensation structure that includes equity awards, base annual cash retainers, and additional cash retainers for committee service. We expect to provide more information regarding such compensation structure in future fiscal years. Executive officers of the Company who also act as directors of the Company do not receive any additional compensation for services rendered in such capacity. See “Fiscal 2026 Summary Compensation Table” above. The aggregate number of Option awards outstanding at the end of fiscal year 2026 for each non-employee director who served during fiscal 2026 was as follows: Mr. Oliver, 160,000 Options; Ms. Guerrero-Mahon, 205,000 Options; Mr. Kehler, 150,000 Options; Mr. Maselli, 150,000 Options; and Mr. Fulton, 50,000 Options. As of June 30, 2026, 76% of the above Options were fully vested. Mr. Beling and Mr. Morris did not hold any outstanding Option awards at the end of fiscal year 2026. Description of the 2017 Amended Long-Term Incentive Plan On April 6, 2026, NioCorp’s shareholders approved the adoption of the 2017 Amended Long-Term Incentive Plan. Under the 2017 Amended Long-Term Incentive Plan, the Board may in its discretion from time-to-time grant Options, share units (in the form of restricted share units (“RSUs”) and performance share units (“PSUs”)) and dividend equivalents to non-employee directors, employees and certain other service providers (as further described in the 2017 Amended Long-Term Incentive Plan) of the Company and affiliated entities selected by the Board. Subject to adjustment as described in the 2017 Amended Long-Term Incentive Plan, and subject to the plan's share counting rules, the aggregate number of Common Shares available for awards under the 2017 Amended Long-Term Incentive Plan may not exceed 11,300,000 Common Shares, minus, as of April 6, 2026, one Common Share for every one Common Share subject to an award granted under the 2017 Amended Long-Term Incentive Plan after February 9, 2026 and before April 6, 2026. The 2017 Amended Long- Term Incentive Plan also limits the maximum annual compensation that may be granted to our non-employee directors for service on the Board to $750,000 (measured as described in the plan document), subject to exceptions for distributions of previously deferred compensation, compensation for services as an executive officer or employee, and non-preferential dividends or dividend equivalents. The following table presents the burn rates for the 2017 Amended Long-Term Incentive Plan for the three most recent fiscal years: Fiscal Year Ending June 30 Number of awards granted Weighted average number of Common Shares outstanding Burn rate 2026 2,282,500 117,214,449 2.0% 2025 945,000 45,072,895 2.1% 2024 1,625,000 34,320,024 4.7%
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100 ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS The following table sets forth the beneficial ownership of Common Shares of NioCorp as of September 25, 2026 (except where otherwise indicated), for the following: (1) each person who is known by NioCorp to beneficially own more than 5% of the outstanding shares of NioCorp’s Common Shares; (2) each of the named executive officers (as defined in the “Fiscal 2026 Summary Compensation Table,” above); (3) each of NioCorp’s directors; and (4) all directors and executive officers of NioCorp as a group. Beneficial ownership of Common Shares in the table below is determined in accordance with the rules of the SEC and includes voting or investment power with respect to the Common Shares. Common Shares that may be acquired by an individual or group within 60 days of September 25, 2026, pursuant to the exercise of Options, the exercise of Warrants, or the exchange of shares of Class B common stock of ECRC (formerly known as GXII), are deemed to be outstanding for the purpose of computing the percentage ownership of such individual or group but are not deemed to be outstanding for the purpose of computing the percentage ownership of any other person shown in the table. Percentage of ownership is based on 145,849,630 Common Shares outstanding as of September 25, 2026. Unless otherwise noted in the table below, Options vested at the grant date. Except as indicated in footnotes to this table, we believe that the shareholders named in this table have sole voting and investment power with respect to all Common Shares shown to be beneficially owned by them, based on information provided to us by such shareholders. Unless otherwise indicated, the address for each director and executive officer listed is: c/o NioCorp Developments Ltd., 7000 South Yosemite Street, Suite 115, Centennial, CO 80112. Name and Address ofBeneficial Owner Position Amount and Nature of Beneficial Ownership(1) (2) Percent of Common Shares Mark A. Smith, PE, Esq.Highlands Ranch, Colorado, USA Chief Executive Officer, President, Executive Chairman and Director 3,469,876 (3) 2.36% Neal ShahSuperior, Colorado, USA Chief Financial Officer and Corporate Secretary 631,294 (4) * Scott HonanCentennial, Colorado, USA Chief Operating Officer 628,636 (5) * Anthony W. FultonLincoln, Nebraska, USA Director 267,709 (6) * Nilsa Guerrero-MahonBrighton, Colorado, USA Director 232,918 (7) * Dean KehlerNew York, New York, USA Director 3,725,311 (8) 2.49% Michael MaselliPelham, New York, USA Director 671,735 (9) * Peter OliverBunbury, Western Australia, Australia Lead Director 140,200 (10) * All current directors, executive officers and named executive officers as a group (10 persons) 10,476,557 6.84%BlackRock, Inc. 9,013,741 (11) 6.18% * Represents ownership of less than 1%. (1) Calculated in accordance with Rule 13d-3 of the Exchange Act. (2) On March 17, 2023, NioCorp effected a 1-to-10 reverse stock split (the “Reverse Stock Split”) of the Common Shares, with any fractional shares resulting from the Reverse Stock Split rounded down to the nearest whole share. All Options and Warrants outstanding as of March 17, 2023, were adjusted to reflect the Reverse Stock Split. Such Options and Warrants initially covered a number of shares equal to the amount reported herein times 10 (and at an exercise price equal to the amount reported herein divided by 10). Class B common stock of ECRC, which may be exchanged for Common Shares upon certain conditions, were issued on a post-Reverse Stock Split basis. (3) Mr. Smith beneficially owns 2,318,819 outstanding Common Shares. In addition, he beneficially owns 275,133 Common Shares issuable upon exercise of: (i) 183,422 Warrants each exercisable for one Common Share at a price of $1.75 until November 13, 2026; and (ii) 91,711 Warrants each exercisable for one Common Share at a price of $2.07 until November 13, 2029. He also beneficially owns 875,924 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 317,236 Common Shares that may be issuable upon exercise of unvested Options. (4) Mr. Shah beneficially owns 75,032 outstanding Common Shares. In addition, he beneficially owns 556,262 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 157,745 Common Shares that may be issuable upon exercise of unvested Options.
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(5) Mr. Honan beneficially owns 55,762 outstanding Common Shares. In addition, he beneficially owns 572,874 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 189,992 Common Shares that may be issuable upon exercise of unvested Options. (6) Mr. Fulton beneficially owns 179,350 outstanding Common Shares. He shares both voting and investment power with respect to 2,276 of such Common Shares with members of his family. In addition, he beneficially owns 54,859 Common Shares issuable upon exercise of 49,058 Warrants assumed by NioCorp in connection with its business combination with GXII (“NioCorp Assumed Warrants”) each exercisable for 1.11829212 Common Shares at a price of $11.50 until March 17, 2028. He shares both voting and investment power with respect to 12,335 Common Shares issuable upon exercise of 11,032 of such NioCorp Assumed Warrants with members of his family. He also beneficially owns 33,500 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 16,500 Common Shares that may be issuable upon exercise of unvested Options. (7) Ms. Guerrero-Mahon beneficially owns 46,068 outstanding Common Shares. In addition, she beneficially owns 186,850 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 18,150 Common Shares that may be issuable upon exercise of unvested Options. (8) Mr. Kehler beneficially owns 212,583 outstanding Common Shares, and 1,441,290 Common Shares issuable upon the exchange of Vested Shares (as defined herein). He shares both voting and investment power with respect to 318,470 of such Vested Shares with U.S. Trust Company of Delaware, as co-trustee of the Elizabeth Kehler 2012 Family Trust under Declaration of Trust dated December 12, 2012 (the “Elizabeth Kehler Trust”). In addition, he beneficially owns 1,937,938 Common Shares issuable upon exercise of the following: (i) 1,657,057 NioCorp Assumed Warrants exercisable for an aggregate of up to 1,853,073 Common Shares held by Mr. Kehler; (ii) 56,577 Warrants each exercisable for one Common Share at a price of $1.75 until November 13, 2026; and (iii) 28,288 Warrants each exercisable for one Common Share at a price of $2.07 until November 13, 2029. He also beneficially owns 133,500 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 16,500 Common Shares that may be issuable upon exercise of unvested Options. The total does not include Common Shares that may be issuable upon exchange of the following: (i) 417,030 that are not exchangeable until the volume-weighted average price of the Common Shares on the principal securities exchange for the Common Shares as reported by Bloomberg (“VWAP”) equals or exceeds approximately $12.00 per share for 20 of any 30 consecutive trading days during the period from the closing of the business combination with GXII on March 17, 2023 through, and including, the tenth anniversary of such date (such period, the “Earnout Share Period”) on any stock exchange on which the Common Shares are then trading (“Tranche I Earnout Shares”) held by Mr. Kehler; (ii) 417,030 that are not exchangeable until the VWAP of the Common Shares equals or exceeds approximately $15.00 per share for 20 of any 30 consecutive trading days during the Earnout Share Period on any stock exchange on which the Common Shares are then trading (“Tranche II Earnout Shares”) held by Mr. Kehler; (iii) 118,284 Tranche I Earnout Shares held by the Elizabeth Kehler Trust; and (iv) 118,284 Tranche II Earnout Shares held by the Elizabeth Kehler Trust. (9) Mr. Maselli beneficially owns 323,085 outstanding Common Shares. In addition, Mr. Maselli beneficially owns 215,150 Common Shares issuable upon exercise of 192,392 NioCorp Assumed Warrants held by Mr. Maselli. He also beneficially owns 133,500 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 16,500 Common Shares that may be issuable upon exercise of unvested Options. The total does not include Common Shares that may be issuable upon exchange of the following: (i) 119,998 Tranche I Earnout Shares held by Mr. Maselli; and (ii) 119,998 Tranche II Earnout Shares held by Mr. Maselli. (10) Mr. Oliver beneficially owns 140,200 Common Shares issuable upon exercise of vested Options each exercisable for one Common Share. The total does not include 19,800 Common Shares that may be issuable upon exercise of unvested Options. (11) Based on a Schedule 13G/A filed on July 29, 2026 by BlackRock, Inc. ("BlackRock") with respect to the Common Shares owned by BlackRock. BlackRock reported sole voting power over 8,796,392 Common Shares and sole dispositive power over 9,013,741 Common Shares. BlackRock's address is 50 Hudson Yards, New York, NY 10001. EQUITY COMPENSATION PLANS The Company has maintained equity compensation plans under which Options have been granted. Option grants have been determined by the Company’s directors and are only provided in compliance with applicable laws and regulatory policy. The following information is provided with respect to compensation plans (including individual compensation arrangements) under which equity securities were authorized for issuance as of June 30, 2026. Equity Compensation Plan Information Plan Category Number of Securities to be Issued Upon Exercise of Outstanding Options, Warrants, and Rights Weighted-Average Exercise Price of Outstanding Options, Warrants, and Rights Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans (Excluding Securities Reflected in Second Column) Equity Compensation Plans Approved by Security Holders 4,147,500 $3.42 11,300,000 Equity Compensation Plans Not Approved by Security Holders — — — Total 4,147,500 $3.42 11,300,000 (1) (2)
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101
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102 (1) Represents Options granted pursuant to the 2017 Amended Long-Term Incentive Plan. (2) As of June 30, 2026, there were: (i) 4,147,500 outstanding securities awarded under the 2017 Amended Long-Term Incentive Plan representing 2.84% of the Company’s currently issued and outstanding Common Shares; and (ii) 11,300,000 remaining securities available for grant representing 7.75% of the Company’s currently issued and outstanding Common Shares. Performance Graph The following graph compares total cumulative shareholder return for $100 invested in Common Shares from July 1, 2021, to June 30, 2026, with cumulative total returns for the Russell 2000 Index and the VanEck Rare Earth & Strategic Metals ETF (REMX). Beginning with fiscal year 2026, the Company changed the indices used in this comparison. The broad equity market index is now the Russell 2000 Index, replacing the S&P/TSX Composite Index. The Company's Common Shares have traded principally on the Nasdaq Stock Market since March 2023, and the Russell 2000 comprises United States issuers of market capitalization comparable to the Company's, making it a more representative broad market comparison than a Canadian composite index. The industry comparison index is now the MVIS Global Rare Earth/Strategic Metals Index, replacing the S&P/TSX Global Mining Index. The Company believes the MVIS index more closely reflects the Company's focus on critical minerals and rare earth elements than a diversified global mining index. Index performance is presented using the VanEck Rare Earth and Strategic Metals ETF (REMX), which tracks that index, as a proxy for total shareholder return. Consistent with Item 201(e) of Regulation S-K, the graph presents the Company's cumulative total return against both the newly selected indices and the indices used for the immediately preceding fiscal year. Overall, the Company’s cumulative return for the five-year period ended below the range of returns for the selected index. As an exploration stage company, the Compensation Committee and the Board have not historically adjusted executive officer compensation to reflect share performance trends. Compensation to executive officers remained flat from 2013 through February 2023, except for increases supported by additional job responsibilities and/or job promotions. Effective April 1, 2023, the Compensation Committee approved a base rate average increase of 12% for all NioCorp employees. There were no salary increases granted during fiscal years 2024 or 2025. In fiscal year 2026, the Compensation Committee approved a base rate average increase of 8% for all NioCorp employees. ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE The following sets forth certain information regarding transactions between the Company (and its subsidiaries) and its officers, directors, and significant shareholders. There have been no other transactions since the end of the Company’s most
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103 recently completed fiscal year and there are no currently proposed transactions in which the Company was or is to be a participant and the amount involved exceeds $120,000, and in which any related person (for purposes of Item 404 of Regulation S-K) had or will have a direct or indirect material interest. Loan Transactions: Mr. Smith is our Chief Executive Officer, President, Executive Chairman, and Director. On September 11, 2024, the Company and Mr. Smith entered into the Smith Loan Agreement pursuant to which Mr. Smith agreed to make available to the Company a non- revolving, multiple draw credit facility of up to $2,000,000. The Smith Loan expired on June 30, 2025, was non-revolving, and amounts paid back under the terms of the Smith Loan Agreement did not again become available for drawdowns at the request of the Company. The Company paid interest to Mr. Smith on amounts outstanding under the Smith Loan at a rate equal to 10% per annum, calculated monthly in arrears, through to the date of repayment of the Loan. Mr. Smith also received an establishment fee equal to 2.5% of the amount of each drawdown payable at the time of the drawdown as consideration of the advancement of such drawdown. Any outstanding balance on the Loan, including accrued interest, were immediately due and payable by the Company on the earlier of the date of expiration of the Smith Loan Agreement and the occurrence of an event of default thereunder (the “Due Date”). The Company could repay the Smith Loan at any time without notice and without penalty, but any amount of principal or interest repaid by the Company prior to the Due Date will be subject to an early payment fee of 2.5% of the value of any such payment. Amounts outstanding under the Smith Loan Agreement were secured by all of the Company’s assets pursuant to a general security agreement between the Company and Mr. Smith, dated September 11, 2024. Through October 30, 2024, the Company borrowed a total of $504,000 under the Smith Loan and the largest aggregate amount of principal outstanding under the Smith Loan Agreement during the period ended June 30, 2025, was $504,000. The Company subsequently repaid $508,200, representing the balance of the principal outstanding under the Smith Loan plus accrued interest, and also repaid $40,850 related to loan origination fees payable. As of June 30, 2026, there was no principal amount or accounts payable outstanding under the Smith Loan. November 2024 Private Offering On November 13, 2024, the Company closed a non-brokered private placement (the “November 2024 Private Offering”) and issued an aggregate of 2,199,602 units of the Company (the “November 2024 Units”). Each November 2024 Unit consists of one Common Share, one Warrant (collectively, the “Series A Private Warrants”) to purchase one Common Share and one-half of one Warrant to purchase one- half of one Common Share (the “Series B Private Warrants” and, together with the Series A Private Warrants, the “November 2024 Private Warrants”). Each Series A Private Warrant is exercisable into one Common Share (a “Series A Warrant Share”) at an exercise price of $1.75 per Series A Warrant Share at any time on or after the date of issuance until November 13, 2026. Each Series B Private Warrant is exercisable into one Common Share (a “Series B Warrant Share”) at an exercise price of $2.07 per Series B Warrant Share at any time beginning six months and one day from the date of issuance until November 13, 2029. Messrs. Kehler and Smith subscribed to purchase an aggregate of 239,999 November 2024 Units in the November 2024 Private Offering and paid a purchase price of $1.7675 per November 2024 Unit (the “November 2024 Insider Unit Price”) upon the closing of the November 2024 Private Offering. The November 2024 Insider Unit Price included $0.125 per November 2024 Private Warrant underlying each November 2024 Unit purchased by directors of the Company. Messrs. Kehler and Smith purchased 56,577 November 2024 Units and 183,422 November 2024 Units, respectively, for aggregate purchase prices of approximately $100,000 and $324,198, respectively. The remaining investors in the November 2024 Private Offering, who are not affiliated with the Company but with whom the Company had a pre-existing relationship, subscribed to purchase an aggregate of 1,959,603 November 2024 Units at a purchase price per November 2024 Unit of $1.57. Gross proceeds to the Company from the November 2024 Private Offering were approximately $3.5 million. Review, Approval or Ratification of Related Person Transactions Other than as described below, the Company does not currently have in place any specific policy or procedure in respect of the review, approval or ratification of any transaction required to be reported under Item 404(a) of Regulation S-K. Sections 147-153 of the BCBCA set out rules and procedures applicable to all British Columbia corporations, pursuant to which a director presented with a resolution in respect of any matter (including an equity issuance) in respect of which he/she has an interest must disclose that interest in writing to the corporation’s board of directors prior to the approval of such matter. This procedure ensures that each equity issuance to a director or officer of the Company is approved by all directors of the Company not involved in such sale. All loan transactions from directors and officers are typically subject to review and approval by the Board prior to acceptance and are documented in the meeting minutes or resolutions related to same. Under its charter, the Audit Committee is responsible for reviewing and approving any related party transaction in advance of such transaction, unless the Chief Financial Officer or General Counsel determines that it is not practicable to wait until the next Audit Committee meeting,
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104 in which case the related party transaction will be submitted to the Chair of the Audit Committee, who will have delegated authority to act between Audit Committee meetings. Director Independence The Company’s Board consists of Messrs. Smith, Fulton, Oliver, Kehler, and Maselli and Ms. Guerrero-Mahon. The Company utilizes the definition of “independent” as it is set forth in Nasdaq Listing Rule 5605(a)(2) (“Rule 5605(a)(2)”) and National Instrument 52-110 Audit Committees (“NI 52-110”). Further, the Board considers all relevant facts and circumstances in its determination of independence of all members of the Board (including any relationships). Currently, Messrs. Fulton, Oliver, Kehler, and Maselli and Ms. Guerrero-Mahon are considered independent directors. Michael J. Morris and David C. Beling, who served as directors of the Company during fiscal 2026, were previously determined by the Board to be independent directors. ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES The following table presents fees for professional services rendered by Deloitte & Touche LLP for the fiscal years ended June 30, 2026 and June 30, 2025, for the audit of the Company’s annual consolidated financial statements and review of consolidated financial statements included in the Company’s filings and fees billed for other services rendered by the firms during those periods (Dollar amounts in the following table are presented in whole dollars). Fiscal Year Ending June 30, Audit Fees ($) Audit-Related Fees ($) Tax Fees ($) All Other Fees ($) 2026 $ 545,100 $ 1,212,703 $ 56,840 $ — 2025 662,712 601,309 94,016 — (1)“Audit Fees” consist of fees billed, or to be billed, for professional services rendered for the audit of our annual consolidated financial statements and reviews of our interim financial statements included in quarterly reports and services normally provided by our independent registered public accounting firm in connection with statutory filings. (2)“Audit-Related Fees” consist of fees billed, or to be billed, related to agreed-upon procedures and services, including for comfort letters, normally provided by our independent registered public accounting firm in connection with debt offerings or regulatory filings. (3)“Tax Fees” include fees for all tax services other than those included in “Audit Fees” and “Audit-Related Fees.” This category includes fees for tax compliance, tax planning, and tax advice. Tax planning and tax advice include assistance with tax audits and appeals, tax advice related to mergers and acquisitions, and requests for rulings or technical advice from tax authorities. For the financial year ended June 30, 2026, these tax services included the preparation of Canadian and U.S. federal and state tax returns and tax planning and tax advice services. (4)“All Other Fees” includes all other non-audit services. Pre-approval Policies The policy of the Audit Committee has been to pre-approve all audit, audit-related and non-audit services performed by our independent auditors and to subsequently review the actual fees and expenses paid to our independent auditors. Accordingly, the Audit Committee pre-approved all audit, audit-related and non-audit services performed by Deloitte & Touche LLP and subsequently reviewed the actual fees and expenses paid for these services. The Audit Committee has determined that the fees paid to Deloitte & Touche LLP for services are compatible with maintaining Deloitte & Touche LLP’s independence as our auditor. All of the services provided during the years ended June 30, 2026 and 2025, were approved by the Audit Committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X. (1) (2) (3) (4)
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105 PART IV ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES The following documents are filed as a part of this report: Financial Statements (1) The Consolidated Financial Statements, together with the report thereon of Deloitte & Touche LLP, dated September 25, 2026, are included as part of Item 8, “Financial Statements and Supplementary Data,” commencing on page 53 above. Page Report of Independent Registered Public Accounting Firms (Deloitte & Touche LLP; Denver, Colorado; PCAOB ID#34) 53 Consolidated Balance Sheets 55 Consolidated Statements of Operations and Comprehensive Loss 56 Consolidated Statements of Cash Flows 57 Consolidated Statements of Shareholders’ Equity and Redeemable Noncontrolling Interest 58 Notes to Consolidated Financial Statements 59
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106 (a) Exhibits Exhibit No. Title 2.1(1)** Business Combination Agreement, dated September 25, 2022, by and among NioCorp Developments Ltd., GX Acquisition Corp. II and Big Red Merger Sub Ltd 2.2(2) Asset Purchase Agreement, dated as of December 4, 2025, by and among NioCorp Advanced Metals and Alloys, LLC, FEA Materials LLC and each member of FEA Materials LLC party thereto 3.1(3) Notice of Articles of NioCorp Developments Ltd., dated April 5, 2016 3.2(3) Articles of NioCorp Developments Ltd., as amended, effective as of January 27, 2015 3.3(4) Amendment to Articles, effective March 17, 2023 4.1(5) Convertible Security Funding Agreement, dated February 16, 2021, between the Company and Lind Global Asset Management III, LLC 4.2(6) Amendment #1 to Convertible Security Funding Agreement, dated December 2, 2021, between the Company and Lind Global Asset Management III, LLC 4.3(7) Waiver and Consent Agreement, dated September 25, 2022, between NioCorp Developments Ltd. and Lind Global Asset Management III, LLC 4.4(8) Form of Lind Contingent Consent Warrants 4.5(1) Sponsor Support Agreement, dated as of September 25, 2022, by and among GX Acquisition Corp. II, NioCorp Developments Ltd., GX Sponsor II LLC, in its capacity as a shareholder of GX Acquisition Corp. II, and certain other shareholders of GX Acquisition Corp. II 4.6(9) Joinder to Sponsor Support Agreement, dated as of March 17, 2023, by and among NioCorp Developments Ltd. and each of the Holders party thereto 4.7(4) Amended and Restated Registration Rights Agreement, dated as of March 17, 2023, by and among NioCorp Developments Ltd., GX Acquisition Corp. II, GX Sponsor II LLC, certain holders of the common shares of the NioCorp Developments Ltd. listed on Schedule 1 thereto, certain current and former stockholders of GX Acquisition Corp. II, and other persons and entities listed on Schedule 2 thereto 4.8(4) Registration Rights Agreement Joinder, dated as of March 17, 2023, by and among NioCorp Developments Ltd. and each of the parties listed on Schedule A thereto 4.9(4) Exchange Agreement, dated as of March 17, 2023, by and among NioCorp Developments Ltd., GX Acquisition Corp. II and GX Sponsor II LLC 4.10(9) Joinder to Exchange Agreement, dated as of March 17, 2023, by and among NioCorp Developments Ltd., Elk Creek Resources Corp (f/k/a GX Acquisition Corp. II) and each of the Holders party thereto 4.11(10) Warrant Agreement, dated March 17, 2021, by and between GX Acquisition Corp. II and Continental Stock Transfer & Trust Company 4.12(4) Assignment, Assumption and Amendment Agreement, dated as of March 17, 2023, by and among GX Acquisition Corp. II, NioCorp Developments Ltd., Continental Stock Transfer & Trust Company, as the existing Warrant Agent, and Computershare Inc. and its affiliate Computershare Trust Company, N.A., as the successor Warrant Agent 4.13(4) Form of Warrant (included in Exhibit 4.12) 4.14(11) Underwriting Agreement, dated as of November 3, 2024, by and between NioCorp Developments Ltd. and Maxim Group LLC 4.15(11) Warrant Agency Agreement, dated as of November 5, 2024, by and between NioCorp Developments Ltd., Computershare Inc. and Computershare Trust Company, N.A. 4.16(11) Form of November 2024 Series A Public Warrant 4.17(11) Form of November 2024 Series B Public Warrant 4.18(12) Form of Subscription Agreement in respect of units issued in November 2024 4.19(12) Form of November 2024 Series A Private Warrant 4.20(12) Form of November 2024 Series B Private Warrant 4.21(13) Placement Agency Agreement, dated as of September 26, 2025, by and between NioCorp Developments Ltd. and Maxim Group LLC 4.22(13) Form of September Pre-Funded Warrant (included in Exhibit 4.21) 4.23(14) Placement Agency Agreement, dated as of October 13, 2025, by and between NioCorp Developments Ltd. and Maxim Group LLC 4.24(14) Form of October Pre-Funded Warrant (included in Exhibit 4.23) 4.25(15) Shareholder Rights Plan Agreement, dated as of November 21, 2025, between NioCorp Developments Ltd. and Computershare Investor Services Inc. 4.26(16) Amended and Restated Shareholder Rights Plan Agreement, dated as of April 6, 2026, by and between NioCorp Developments Ltd. and Computershare Investor Services Inc. as rights agent (or any successor rights agent) 4.27(17) Placement Agency Agreement, dated as of February 24, 2026, by and between NioCorp Developments Ltd. and Maxim Group LLC 4.28(17) Form of February Pre-Funded Warrant (included in Exhibit 4.27) 4.29 Description of Securities 10.1(3)# Consulting Agreement, dated May 13, 2014, between the Company and KMSmith, LLC 10.2(18)# Amendment to Contract, dated September 1, 2019, between the Company and KMSmith, LLC
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107 10.3(18)# Contract Assignment and Novation Agreement, dated as of August 31, 2020, among the Company, KMSmith, LLC and 76 Resources, Inc. 10.4(19)# Contract Assignment and Novation Agreement, dated as of August 1, 2021, among the Company, 76 Resources, Inc. and 76 Resources, LLC 10.5(20)# Amendment to Contract, dated April 1, 2023, between the Company and 76 Resources, LLC 10.6(21)# Amendment to Contract, dated August 18, 2025, between the Company and 76 Resources, LLC 10.7(22)* Offtake agreement, dated June 13, 2016, between the Company and CMC Cometals, a division of Commercial Metals Company 10.8(23) Amendment No. 1 to Offtake Agreement, dated April 13, 2020, between the Company and Traxys North America LLC, as assignee 10.9(24) Offtake agreement with ThyssenKrupp Metallurgical Products GmbH 10.10(4)# Form of Director and Officer Indemnification Agreement 10.11(1)# Employment Agreement, dated as of September 25, 2022, by and between Elk Creek Resources Corporation and Neal Shah 10.12(1)# Employment Agreement, dated as of September 25, 2022, by and between Elk Creek Resources Corporation and Scott Honan 10.13(1)# Employment Agreement, dated as of September 25, 2022, by and between Elk Creek Resources Corporation and Jim Sims 10.14# Employment Agreement, dated as of July 1, 2026, by and between Elk Creek Resources Corporation and Ernest Cleave 10.15(1)# Form of Restrictive Covenant Agreement 10.16(16)# NioCorp Developments Ltd. Long-Term Incentive Plan, as amended through April 6, 2026 10.17# Form of Option Certificate 10.18(25) Loan Agreement, dated as of September 11, 2024, between the Company and Mark Smith 10.19(25) Security Agreement, dated as of September 11, 2024, between the Company and Mark Smith 10.20(21) Defense Industrial Base Consortium Base Agreement, dated as of July 22, 2025, between Elk Creek Resources Corp. and Advanced Technology International. 10.21(21) Project Sub Agreement, dated as of August 4, 2025, by and between Elk Creek Resources Corp. and Advanced Technology International 19.1(8) NioCorp Developments Ltd. Insider Trading Policy 21.1 Subsidiaries of NioCorp Developments Ltd. 23.1 Consent of Deloitte & Touche LLP 23.2 Consent of Dahrouge Geological Consulting USA Ltd. 23.3 Consent of SMH Process Innovation 23.4 Consent of Dumas Contracting USA Inc. 23.5 Consent of Amplify Mine Planning LLC 23.6 Consent of BBA Consultants International LP 23.7 Consent of Olsson 23.8 Consent of Adrian Brown Consultants Inc. 23.9 Consent of Andrieux & Associates Geomechanics Consulting, L.P. 23.10 Consent of Tetra Tech 23.11 Consent of T Engineering 23.12 Consent of Magemi Mining Inc. 23.13 Consent of Metallurgy Concept Solutions 23.14 Consent of Scott Honan, M.Sc., SME-RM 31.1 Certification of the Chief Executive Officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 31.2 Certification of the Chief Financial Officer pursuant to Exchange Act Rules 13a-14(a) and 15d-14(a), as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 32.1 Certification of the Chief Executive Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes- Oxley Act of 2002 32.2 Certification of the Chief Financial Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes- Oxley Act of 2002 95.1 Mine Safety Disclosure 96.1 2026 S-K 1300 Elk Creek Technical Report Summary 97.1(8) Compensation Clawback Policy 101.INS(26) XBRL Instance Document 101.SCH(26) XBRL Taxonomy Extension – Schema 101.CAL(26) XBRL Taxonomy Extension – Calculations 101.DEF(26) XBRL Taxonomy Extension – Definitions 101.LAB(26) XBRL Taxonomy Extension – Labels 101.PRE(26) XBRL Taxonomy Extension – Presentations 104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) # Management compensation plan, arrangement or agreement. * Portions of this exhibit have been omitted pursuant to Item 601(b)(10)(iv) of Regulation S-K, which portions will be furnished to the Securities and Exchange Commission upon request.
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108 ** Certain exhibits to this agreement have been omitted pursuant to Item 601(a)(5) of Regulation S-K. A copy of any omitted exhibit will be furnished to the Securities and Exchange Commission upon request. (1) Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 000-55710) filed with the SEC on September 29, 2022 and incorporated herein by reference. (2) Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on December 4, 2025, and incorporated herein by reference. (3) Previously filed as an exhibit to the Company’s Draft Registration Statement on Form S-1 (Registration No. 377-01354) submitted to the SEC on July 26, 2016 and incorporated herein by reference. (4) Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on March 17, 2023 and incorporated herein by reference. (5) Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 000-55710) filed with the SEC on February 17, 2021 and incorporated herein by reference. (6) Previously filed as an exhibit to the Company’s Quarterly Report on Form 10-Q (File No. 000-55710) filed with the SEC on February 4, 2022 and incorporated herein by reference. (7) Previously filed as an exhibit to the Company’s Registration Statement on Form S-4 (Registration No. 333-268227) filed with the SEC on November 7, 2022 and incorporated herein by reference. (8) Previously filed as an exhibit to the Company’s Annual Report on Form 10-K (File No. 001-41655) filed with the SEC on September 23, 2024 and incorporated herein by reference. (9) Previously filed as an exhibit to the Company’s Registration Statement on Form S-3 (File No. 333-271268) filed with the SEC on April 14, 2023 and incorporated herein by reference. (10)Previously filed as an exhibit to Elk Creek Resources Corp.’s (f/k/a GX Acquisition Corp. II) Current Report on Form 8-K (File No. 001-40226) filed with the SEC on March 22, 2021 and incorporated herein by reference. (11)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on November 5, 2024 and incorporated herein by reference. (12)Previously filed as an exhibit to the Company’s Quarterly Report on Form 10-Q (File No. 001-41655) filed with the SEC on November 13, 2024 and incorporated herein by reference. (13)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on September 29, 2025 and incorporated herein by reference. (14)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on October 15, 2025 and incorporated herein by reference. (15)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on November 21, 2025 and incorporated herein by reference. (16)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on April 6, 2026 and incorporated herein by reference (17)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on February 25, 2026 and incorporated herein by reference (18)Previously filed as an exhibit to the Company’s Annual Report on Form 10-K (File No. 000-55710) filed with the SEC on September 16, 2020 and incorporated herein by reference. (19)Previously filed as an exhibit to the Company’s Annual Report on Form 10-K (File No. 000-55710) filed with the SEC on September 8, 2021 and incorporated herein by reference. (20)Previously filed as an exhibit to the Company’s Post-Effective Amendment No. 1 to the Registration Statement on Form S-3 on Form S-1 (File No. 333-271268) filed with the SEC on August 22, 2023 and incorporated herein by reference. (21)Previously filed as an exhibit to the Company’s Quarterly Report on Form 10-Q (File No. 001-41655) filed with the SEC on November 13, 2025 and incorporated herein by reference. (22)Previously filed as an exhibit to the Company’s Registration Statement on Form S-1 (Registration No. 333-213451) filed with the SEC on September 2, 2016 and incorporated herein by reference. (23)Previously filed as an exhibit to Amendment No. 1 to the Company’s Annual Report on Form 10-K/A (File No. 000-55710) filed with the SEC on October 31, 2022 and incorporated herein by reference. (24)Previously filed as an exhibit to the Company’s Annual Report on Form 10-K (File No. 000-55710) filed with the SEC on August 29, 2017 and incorporated herein by reference.
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109 (25)Previously filed as an exhibit to the Company’s Current Report on Form 8-K (File No. 001-41655) filed with the SEC on September 11, 2024 and incorporated herein by reference. (26)Submitted Electronically Herewith. Attached as Exhibit 101 to this report are the following formatted in XBRL (Extensible Business Reporting Language): (i) the Consolidated Balance Sheets at June 30, 2026 and June 30, 2025, (ii) the Consolidated Statements of Operations and Comprehensive Loss for the years ended June 30, 2026 and 2025, (iii) the Consolidated Statements of Cash Flows for the years ended June 30, 2026 and 2025, (iv) the Consolidated Statements of Shareholders’ Equity and Redeemable Noncontrolling Interest for the years ended June 30, 2026 and 2025, (v) the Notes to the Consolidated Financial Statements. ITEM 16. FORM 10–K SUMMARY None.
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110 SIGNATURES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. NIOCORP DEVELOPMENTS LTD. By:/s/ Neal Shah Neal Shah Chief Financial Officer September 25, 2026 Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities indicated on September 25, 2026. Signature Title /s/ Mark A. Smith President, Chief Executive Officer (Principal Mark A. Smith Executive Officer and Authorized U.S. Representative) and Chairman of the Board of Directors /s/ Neal Shah Chief Financial Officer (Principal Financial and Neal Shah Accounting Officer) /s/ Anthony W. Fulton Director Anthony W. Fulton /s/ Nilsa Guerrero-Mahon Director Nilsa Guerrero-Mahon /s/ Dean C. Kehler Director Dean C. Kehler /s/ Michael G. Maselli Director Michael G. Maselli /s/ Peter Oliver Director Peter Oliver
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EXHIBIT 4.29 DESCRIPTION OF SECURITIES Common Shares The authorized capital of NioCorp Developments Ltd., a British Columbia corporation (the “Company”), consists of an unlimited number of common shares, without par value, of the Company (the “Common Shares”). The holders of Common Shares are entitled to receive notice of and attend all meetings of shareholders, with each Common Share held entitling the holder to one (1) vote on any resolution to be passed at such shareholder meetings. The holders of Common Shares are entitled to dividends if, as and when declared by the Company’s Board of Directors (the “Board”). The Common Shares are entitled, upon liquidation, dissolution, or winding up of the Company, to receive the remaining assets of the Company available for distribution to shareholders. There are no pre-emptive, conversion, or redemption rights attached to the Common Shares. Exchange Controls There are no governmental laws, decrees, or regulations in Canada that restrict the export or import of capital, including foreign exchange controls, or that affect the remittance of dividends, interest or other payments to non-resident holders of the securities of the Company, other than as discussed below and Canadian withholding tax. See “—Certain Canadian Federal Income Tax Considerations for U.S. Residents” below. Competition Act Limitations on the ability to acquire and hold Common Shares may be imposed by the Competition Act (Canada). This legislation permits the Commissioner of Competition of Canada (the “Commissioner”) to review any acquisition of a significant interest in the Company. This legislation grants the Commissioner jurisdiction to challenge such an acquisition before the Canadian Competition Tribunal if the Commissioner believes that it would, or would be likely to, result in a substantial lessening or prevention of competition in any market in Canada. Investment Canada Act The Investment Canada Act subjects an acquisition of control of a Canadian business by a non-Canadian to government notification or review depending on whether the relevant financial threshold (based on enterprise value or asset value of the company), as calculated pursuant to the legislation, is exceeded. A reviewable acquisition may not proceed unless the relevant minister is satisfied that the investment is likely to result in a net benefit to Canada. Under the national-security-review regime in the Investment Canada Act, review on a discretionary basis may also be undertaken by the federal government in respect of a broad range of investments by a non-Canadian. No financial threshold applies to a national security review. The relevant test is whether such investment by a non-Canadian could be “injurious to national security.” Certain Canadian Federal Income Tax Considerations for U.S. Residents The following generally summarizes certain Canadian federal income tax consequences generally applicable under the Income Tax Act (Canada) and the regulations enacted thereunder (collectively, the “Canadian Tax Act”) and the Canada-United States Tax Convention (1980) (the “Convention”) to the holding and disposition of Common Shares. Comment is restricted to holders of Common Shares each of whom, at all material times for the purposes of the Canadian Tax Act and the Convention, (i) is resident solely in the U.S. for tax purposes, (ii) is a “qualifying person” under and entitled to the benefits of the Convention, (iii) holds all Common Shares as capital property, (iv) deals at arm’s length with and is not affiliated with the Company, (v) does not and is not deemed to use or hold any Common Shares in a business carried on in Canada (including an adventure or concern in the nature of trade), (vi) is not an insurer that carries on business in Canada and elsewhere, (vii) is not an “authorized foreign bank” (as defined in the Canadian Tax Act), (viii) has not entered into a “derivative forward agreement”, “synthetic equity arrangement” or
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“synthetic disposition arrangement” (each as defined in the Canadian Tax Act) with respect to the Common Shares, and (ix) does not have and has not had, at any time, a “permanent establishment” (as defined in the Convention) of any kind in Canada (each such holder, a “U.S. Resident Holder”). Certain U.S.-resident entities that are fiscally transparent for U.S. federal income tax purposes (including limited liability companies) may not in all circumstances be entitled to the benefits of the Convention. Members of or holders of an interest in such an entity that holds Common Shares should consult their own tax advisers regarding the extent, if any, to which the benefits of the Convention will apply to the entity in respect of its Common Shares. Generally, a U.S. Resident Holder’s Common Shares will be considered to be capital property of such holder provided that the U.S. Resident Holder is not a trader or dealer in securities, did not acquire, hold, or dispose of the Common Shares in one or more transactions considered to be an adventure or concern in the nature of trade (i.e. speculation), and does not hold the Common Shares in the course of carrying on a business. This summary is based on the current provisions of the Canadian Tax Act and the Convention in effect as of the date prior to the date hereof, all specific proposals to amend the Canadian Tax Act and the Convention publicly and officially announced by or on behalf of the Minister of Finance (Canada) prior to the date hereof (the “Tax Proposals”), and the current administrative policies and assessing practices of the Canada Revenue Agency (the “CRA”) published in writing and made publicly available by the CRA prior to the date hereof. This summary assumes that the Tax Proposals will be enacted as currently proposed, and that there will be no other material change to any applicable law or administrative policy or assessing practice, whether by way of judicial, legislative or governmental decision or action, although no assurance can be given in these respects. Except as otherwise expressly provided, this summary does not take into account any provincial, territorial, or foreign tax considerations, which may differ materially from those set out herein. This summary is of a general nature only, is not exhaustive of all possible Canadian federal income tax considerations and is not intended to be and should not be construed as legal or tax advice to any particular U.S. Resident Holder, and no representations with respect to the tax consequences to any U.S. Resident Holder are made herein. The tax consequences of holding and disposing of Common Shares will vary according to the U.S. Resident Holder’s particular circumstances. U.S. Resident Holders are urged to consult their own tax advisers for advice with respect to their particular circumstances. The discussion below is qualified accordingly. In general, for purposes of the Canadian Tax Act, all amounts relating to the holding or disposition of Common Shares must be converted into Canadian dollars based on the relevant exchange rate as determined in accordance with the Canadian Tax Act. A U.S. Resident Holder generally will not be subject to tax under the Canadian Tax Act in respect of a capital gain realized on the disposition or deemed disposition of one or more Common Shares, nor will a capital loss arising therefrom be recognized under the Canadian Tax Act, unless such Common Shares constitute “taxable Canadian property” (as defined in the Canadian Tax Act) of the U.S. Resident Holder at the time of disposition and the U.S. Resident Holder is not entitled to relief under the Convention. Generally, a U.S. Resident Holder’s Common Shares will not constitute “taxable Canadian property” of such holder at a particular time at which the Common Shares are listed on a “designated stock exchange” (which currently includes Nasdaq) unless at any time during the 60-month period that ends at the particular time both of the following conditions are concurrently met: 1. 25% or more of the issued shares of any class of the capital stock of the Company were owned by or belonged to one or any combination of: (a) the U.S. Resident Holder, (b) persons with whom the U.S. Resident Holder did not deal at arm’s length, and
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(c) partnerships in which the U.S. Resident Holder or a person referred to in clause (b) holds a membership interest directly or indirectly through one or more partnerships, and 2. more than 50% of the fair market value of the Common Shares was derived directly or indirectly from, one or any combination of, real or immovable property situated in Canada, “Canadian resource properties” (as defined in the Canadian Tax Act), “timber resource properties” (as defined in the Canadian Tax Act), or options in respect of, or interests in, or for civil law rights in, any of the foregoing, whether or not the property exists. Pursuant to Tax Proposals released by the Department of Finance (Canada) on July 23, 2026 (the “TCP Proposals”), shares that are listed on a designated stock exchange would be deemed to include an option, an interest or a right in such shares, whether or not such shares exist, such that any such options, interests or rights held by a U.S. Resident Holder would be included in determining whether such U.S. Resident Holder exceeds the 25% threshold described in (1) above. The TCP Proposals are proposed to come into force on Royal Assent. Notwithstanding the foregoing, Common Shares may also be deemed to be “taxable Canadian property” in certain circumstances set out in the Canadian Tax Act. U.S. Resident Holders whose Common Shares are or may be “taxable Canadian property” should consult their own tax advisors with respect to the tax and compliance considerations that may be relevant to them, including with respect to any potential relief under the Convention. A U.S. Resident Holder to whom the Company pays or credits or is deemed to pay or credit a dividend on such holder’s Common Shares will be subject to Canadian withholding tax, and the Company will be required to withhold the tax from the dividend and remit it to the CRA for the holder’s account. The rate of withholding tax under the Canadian Tax Act is 25% of the gross amount of the dividend, but should generally be reduced under the Convention to 15% (or, if the U.S. Resident Holder is a company which is the beneficial owner of at least 10% of the voting stock of the Company, 5%) of the gross amount of the dividend. For this purpose, a company that is a resident of the U.S. for purposes of the Canadian Tax Act and the Convention and is entitled to the benefits of the Convention shall be considered to own the voting stock of the Company owned by an entity that is considered fiscally transparent under the laws of the U.S. and that is not a resident of Canada, in proportion to such company’s ownership interest in that entity. Shareholder Rights Plan On November 21, 2025, the Board approved the Company’s limited-duration shareholder rights plan (the “Rights Plan”) as set forth in the Shareholder Rights Plan Agreement, dated as of November 21, 2025 (the “Original Rights Plan Agreement”), by and between the Company and Computershare Investor Services Inc., as rights agent (or any successor rights agent) (the “Rights Agent”). The Board adopted the Rights Plan to help ensure that all shareholders of the Company are treated equally and fairly in the event of any unsolicited take-over bid or other attempt to acquire control of the Company (including by way of a “creeping take-over bid”). On April 6, 2026, following approval by the Company’s shareholders at the Company’s Annual Meeting of Shareholders, the Company entered into an Amended and Restated Shareholder Rights Plan Agreement (the “Amended Rights Plan Agreement”), by and between the Company and the Rights Agent, which amends and restates the Original Shareholder Rights Plan Agreement in its entirety. Effective Date and Term The Rights Plan originally became effective on November 21, 2025, after approval by the Board on November 21, 2025. As amended pursuant to the Amended Rights Plan Agreement, the Rights Plan will expire at 5:00 p.m. (Toronto time) on the date of the Company’s annual general meeting of shareholders held in 2027, or earlier upon the redemption of the Rights (as defined below), or provided that a Flip-in Event (as defined below) has not occurred, at such date or time as the Board may determine in its sole discretion (the “Expiration Time”).
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Issue of Rights At the close of business on December 4, 2025 (the “Record Time”), one right (a “Right”) was issued and attached to each Common Share outstanding as at the Record Time. Thereafter, one Right will attach to each Common Share issued after the Record Time and prior to the earlier of the Separation Time (as defined below) and the Expiration Time. Rights Exercise Privilege The Rights are not exercisable initially. The Rights generally separate from the Common Shares and become exercisable (A) ten trading days after the earlier of (i) the first date of public announcement or disclosure by the Company or an Acquiring Person (as defined in the Amended Rights Plan Agreement) of facts indicating that a person has become an Acquiring Person (such date being the “Stock Acquisition Date”), (ii) the date of the commencement of or first public announcement or disclosure of the current intention of any person (other than the Company or any of its subsidiaries) to commence a take-over bid which would result in such person becoming the Beneficial Owner (as defined in the Amended Rights Plan Agreement) of 20% or more of the outstanding Common Shares and any other shares in the capital of the Company entitled to vote generally in the election of directors (collectively, “Voting Shares”), other than pursuant to a Permitted Bid or a Competing Permitted Bid (each as defined below), and (iii) the date on which a Permitted Bid or a Competing Permitted Bid ceases to qualify as such, or (B) such later time as may be determined by the Board (in any such case, the “Separation Time”). From and after the Separation Time and prior to the Expiration Time, each Right will entitle the holder thereof to purchase one Common Share for the Exercise Price (as defined in the Amended Rights Plan Agreement) as at the business day immediately preceding the Separation Time, subject to certain adjustments, including in connection with a Flip-in Event, as described below. The transaction or event in or pursuant to which any Acquiring Person becomes the Beneficial Owner of 20% of the outstanding Voting Shares, other than by way of a Permitted Bid or a transaction otherwise permitted by the Rights Plan, is referred to as a “Flip-in Event.” Any Rights held by an Acquiring Person (or any Affiliate or Associate (as each such term is defined in the Amended Rights Plan Agreement) of an Acquiring Person or any other person acting jointly or in concert with an Acquiring Person or any Affiliate or Associate of such other person) will become null and void upon the occurrence of a Flip-in Event. Ten trading days after the Stock Acquisition Date, each Right (excluding Rights held by an Acquiring Person (or any Affiliate or Associate of an Acquiring Person or any other person acting jointly or in concert with an Acquiring Person or any Affiliate or Associate of such other person or certain transferees) which have become void) will permit the purchase of that number of Common Shares having an aggregate Market Price (as defined in the Amended Rights Plan Agreement) on the date of consummation or occurrence of such Flip-in Event equal to twice the Exercise Price for an amount in cash equal to the Exercise Price. The “Exercise Price” is defined, for the period from and after the Separation Time, as an amount equal to three (3) times the Market Price per Common Share determined as at the Separation Time. For instance, if the Market Price at the Separation Time is $10 per share, the Exercise Price would be $30 and each Right would entitle the holder to acquire Common Shares having an aggregate Market Price on the date of consummation or occurrence of a Flip-in Event of $60 (i.e., twice the Exercise Price [2 x $30]) in exchange for cash consideration equal to the Exercise Price. In effect, each shareholder (other than an Acquiring Person (or any Affiliate or Associate of an Acquiring Person or any other person acting jointly or in concert with an Acquiring Person or any Affiliate or Associate of such other person or certain transferees)) will have the right, upon the occurrence of a Flip-in Event, to acquire six (6) Common Shares at a price equal to $30 (or 50% of the Market Price, as determined for the purposes of the Rights Plan), assuming the Market Price per Common Share on the date of consummation or occurrence of a Flip-in Event is $10. The Amended Rights Plan Agreement provides for certain adjustments to the Exercise Price and the number of Rights outstanding upon the occurrence of certain events, including, without limitation, the declaration or payment of a stock dividend on the Common Shares, the subdivision or consolidation of the outstanding Common Shares, and the fixing of a record date for distributions to all holders of Common Shares. Trading of Rights Until the Separation Time, the Rights will be evidenced by the certificates or book entries representing the associated Common Shares and will be transferable only together with the associated Common Shares. Promptly
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following the Separation Time, the Company will determine whether it wishes to issue separate certificates evidencing the Rights (“Rights Certificates”) or whether it will maintain the Rights in book entry form. If the Company decides to maintain Rights in book entry form, it will put in place such alternative procedures as are determined necessary in consultation with the Rights Agent for the Rights to be maintained in book entry form. In the event that the Company determines to issue Rights Certificates, then promptly following the Separation Time, Rights Certificates will be sent to holders of record of Common Shares (other than an Acquiring Person or certain transferees) as of the Separation Time. Rights Certificates will also be issued for Rights in respect of Common Shares issued after the Separation Time and before the Expiration Time, to each holder (other than an Acquiring Person or certain transferees) converting securities that are exchangeable for Common Shares after the Separation Time. Rights will trade separately from the Common Shares after the Separation Time. Permitted Lock-up Agreements A bidder may enter into lock-up agreements (a “Permitted Lock-Up Agreement”) with shareholders whereby such shareholders agree to deposit or tender their Voting Shares and/or Convertible Securities (as defined in the Amended Rights Plan Agreement) to a take-over bid (the “Lock-Up Bid”) without a Flip-in Event occurring, because such Voting Shares and/or Convertible Securities will not be deemed to be beneficially owned by the bidder for purposes of the Amended Rights Plan Agreement. Such Permitted Lock-Up Agreement must be publicly disclosed and permit the shareholder to terminate its obligation to deposit or tender Voting Shares and/or Convertible Securities or not to withdraw its securities from the Permitted Lock-Up Agreement in order to deposit or tender the Voting Shares and/or Convertible Securities to another take-over bid or support another transaction that in either case (A)(i) will provide a greater price or value to the shareholder than the Lock-Up Bid or (ii) contains an offer price or value for each Voting Share or Convertible Security that exceeds by as much as or more than a specified amount, which specified amount may not be greater than 7% of the price or value to the shareholder of the Lock-Up Bid, and (B) if the number of Voting Shares or Convertible Securities to be purchased under the Lock-Up Bid is less than 100% of the Voting Shares or Convertible Securities held by Independent Shareholders (as defined below), the number of Voting Shares or Convertible Securities to be purchased under such other take-over bid or transaction at a price or value that is not less than the Lock-Up Bid (i) will be greater than the number of Voting Shares or Convertible Securities offered to be purchased under the Lock-Up Bid or (ii) exceeds the number of Voting Shares or Convertible Securities offered to be purchased under the Lock-Up Bid by as much or more than a specified amount, which specified amount may not be greater than 7% of the number of Voting Shares or Convertible Securities offered to be purchased under the Lock-Up Bid. In addition, such Permitted Lock-Up Agreement must provide that no “break-up” fees, “top-up” fees, penalties, expenses or other amounts that exceed, in the aggregate, the greater of (i) the cash equivalent of 2.5% of the price or value of the consideration payable under the Lock-Up Bid to such shareholder and (ii) 50% of the increase in the consideration received under another take-over bid or transaction shall be payable by the shareholder if the shareholder fails to deposit or tender its securities to the Lock-Up Bid, withdraws Voting Shares and/or Convertible Securities previously deposited or tendered thereto or supports another transaction. Permitted Bid Requirements A “Permitted Bid” is a take-over bid, made by an Offeror (as defined below) by way of take-over bid circular, which also complies with the following additional provisions: • the take-over bid is made to all holders of Voting Shares on the books of the Company, other than the Offeror; • the take-over bid contains an irrevocable and unqualified provision that no Voting Shares and/or Convertible Securities will be taken up or paid for pursuant to the take-over bid unless more than 50% of the Voting Shares held by Independent Shareholders (i) shall have been deposited or tendered pursuant to the take-over bid and not withdrawn and (ii) have previously been or are taken up at the same time; • the take-over bid contains, and the take-up and payment for securities tendered or deposited is subject to, an irrevocable and unqualified provision that no Voting Shares and/or Convertible Securities will be taken up or paid for pursuant to the take-over bid prior to the close of business on the date that is not less than (i) 105
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days following the date of the take-over bid or (ii) the last day of such shorter minimum deposit period for which a take-over bid (that is not exempt from any requirements of Division 5 (Bid Mechanics) of National Instrument 62-104 – Take-Over Bids and Issuer Bids (“NI 62-104”)) must remain open for deposits of securities, in the applicable circumstances at such time, pursuant to section 2.28.2 or section 2.28.3 of NI 62-104; • the take-over bid contains an irrevocable and unqualified provision that unless the take-over bid is withdrawn, Voting Shares and/or Convertible Securities may be deposited or tendered pursuant to such take-over bid at any time during the period of time between the date of the take-over bid and the date on which Voting Shares may be taken up and paid for and that any Voting Shares deposited pursuant to the take-over bid may be withdrawn until taken up and paid for; and • the take-over bid contains an irrevocable and unqualified provision that if, on the date on which Voting Shares may be taken up and paid for under the take-over bid, more than 50% of the Voting Shares held by Independent Shareholders have been deposited or tendered pursuant to the take-over bid and not withdrawn, the Offeror will make a public announcement of that fact and the take-over bid will remain open for deposits and tenders of Voting Shares and/or Convertible Securities for not less than ten days from the date of such public announcement. For purposes of the Amended Rights Plan Agreement, (i) should a take-over bid which qualified as a Permitted Bid cease to be a Permitted Bid because it ceases to meet any or all of the requirements mentioned above prior to the time it expires (after giving effect to any extension) or is withdrawn, any acquisition of Voting Shares and/or Convertible Securities made pursuant to such take-over bid shall not be a Permitted Bid Acquisition (as defined in the Amended Rights Plan Agreement) and (ii) the term “Permitted Bid” shall include a Competing Permitted Bid. “Independent Shareholders” is defined in the Amended Rights Plan Agreement as holders of outstanding Voting Shares, other than any Acquiring Person, any person that is making or has announced a current intention to make a take-over bid but only so long as the take- over bid so announced or made has not been withdrawn or terminated or has not expired (an “Offeror”) (other than a person who by virtue of the exception for investment advisors described below is not deemed to beneficially own the Voting Shares held by such person for purposes of the Amended Rights Plan Agreement), Affiliates or Associates of an Acquiring Person or Offeror, any person acting jointly or in concert with such Acquiring Person or Offeror (which excludes customary agreements with and between underwriters and/or banking group members and/or selling group members with respect to a distribution of securities of the Company, pledges of securities in the ordinary course of business and Permitted Lock-Up Agreements) and any employee benefit, deferred profit sharing plan, stock participation plan and any other similar plan or trust for the benefit of employees of the Company or a subsidiary, unless the beneficiaries of the plan or trust direct the manner in which the Voting Shares are to be voted or withheld from voting or direct whether the Voting Shares are to be deposited or tendered to a take-over bid. The Rights Plan allows for a Competing Permitted Bid to be made while a Permitted Bid is in existence. A “Competing Permitted Bid” is a take-over bid that: • is made after a Permitted Bid or another Competing Permitted Bid has been made and prior to the expiry, termination or withdrawal of such Permitted Bid or Competing Permitted Bid; • complies with all of the provisions of a Permitted Bid other than the condition set forth in the third bullet of the definition of a Permitted Bid above; and • contains, and the take-up and payment for securities tendered or deposited is subject to, an irrevocable and unqualified provision that no Voting Shares will be taken up or paid for pursuant to the take-over bid prior to the close of business on the date that is no earlier than the date on which Voting Shares may be taken up under any Permitted Bid (determined as of the date of making the take-over bid, assuming no amendment or variation to the terms and satisfaction of all conditions to the completion of the Permitted Bid) that preceded the Competing Permitted Bid;
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provided that, should a Competing Permitted Bid cease to be a Competing Permitted Bid because it ceases to meet any or all of the requirements mentioned above prior to the time it expires (after giving effect to any extension) or is withdrawn, then any acquisition of Voting Shares made pursuant to such Competing Permitted Bid, including any acquisition of Voting Shares made prior to such time, shall not be a Permitted Bid Acquisition. Waiver The Board, acting in good faith, may, until the occurrence of a Flip-in Event, waive the application of the Rights Plan to a particular Flip-in Event where it would occur by reason of a take-over bid which is made by a take-over bid circular sent to all holders of Voting Shares. Where the Board exercises such waiver power for a particular Flip-in Event, the Board shall be deemed to have exercised such waiver power to any other Flip-in Events subsequently occurring by reason of a take-over bid which is made by means of a take-over bid circular to all holders of Voting Shares prior to the expiry of any other bid for which the Rights Plan is, or is deemed to have been, waived. The Board may, in respect of any Flip-in Event, waive the application of the Rights Plan to a particular Flip-in Event where the Board has determined within ten trading days following a Stock Acquisition Date that the Acquiring Person became an Acquiring Person by inadvertence and without any intent or knowledge that it would become an Acquiring Person and such person has reduced its beneficial ownership within fourteen days after the foregoing determination by the Board such that it is no longer an Acquiring Person. The Board, acting in good faith, may, with the approval of a majority of votes cast by the Independent Shareholders voting in person or by proxy at a meeting duly called for that purpose, determine, at any time prior to the occurrence of a Flip-in Event, to waive the application of the Rights Plan for any Flip-in Event. Redemption The Board, with prior approval of the holders of Voting Shares or the holders of Rights, at any time prior to the occurrence of a Flip- in Event, may redeem all of the then outstanding Rights at a price of $0.00001 each, subject to adjustment. Amendment The Board may amend the Amended Rights Plan Agreement with the prior approval of the holders of Voting Shares (or holders of Rights if the Separation Time has occurred). The Board, without such approval, may make amendments to the Amended Rights Plan Agreement to correct any clerical or typographical error, which are required to maintain the validity of the Amended Rights Plan Agreement as a result of any change in any applicable legislation or regulations or rules thereunder, or to cure any ambiguity, to correct or supplement any provision therein which may be defective or inconsistent with any other provision therein, or to make any other provisions with respect to matters or questions arising thereunder, provided that such action shall not adversely affect the interests of the holders of Voting Shares or Rights in any material respect. Exception for Investment Advisors Investment managers (for client accounts), trust companies (acting in their capacity as trustees or administrators or in a similar capacity), statutory bodies managing investment funds (for employee benefit plans, pension plans, insurance plans or various public bodies) and registered pension funds or plans and their administrators or trustees who become the Beneficial Owner of 20% or more of the outstanding Voting Shares are exempted from triggering a Flip-in Event, provided that they are not making and have not announced an intention to make, a take-over bid, alone or by acting jointly or in concert with any other person.
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Warrants From time to time, the Company has outstanding Common Share purchase warrants (“Warrants”), with each Warrant exercisable for one Common Share. Except with respect to pre-funded Warrants, the exercise price per Common Share and the number of Common Shares issuable upon exercise of Warrants is subject to adjustment upon the occurrence of certain events, including, but not limited to, the following: • the subdivision or re-division of the outstanding Common Shares into a greater number of Common Shares; • the reduction, combination or consolidation of the outstanding Common Shares into a lesser number of Common Shares; • the issuance of Common Shares or securities exchangeable for, or convertible into, Common Shares to all or substantially all of the holders of Common Shares by way of stock dividend or other distribution (other than a distribution of Common Shares upon the exercise of Warrants or any outstanding options); • the reorganization of the Company or the consolidation or merger or amalgamation of the Company with or into another corporate body; and • a reclassification or other similar change to the outstanding Common Shares. The Company generally will issue the Common Shares issuable upon exercise of Warrants within five business days following its receipt of notice of exercise and payment of the exercise price, subject to surrender of the Warrants. Prior to the exercise of any Warrants, holders of the Warrants will not have any of the rights of holders of the Common Shares issuable upon exercise, including the right to vote or to receive any payments of dividends on the Common Shares issuable upon exercise. NioCorp Assumed Warrants On March 17, 2023, the Company closed a series of transactions (the “GXII Transaction”) pursuant to the Business Combination Agreement, dated as of September 25, 2022 (the “Business Combination Agreement”), by and among the Company, GX Acquisition Corp. II, a Delaware corporation (“GXII”), and Big Red Merger Sub Ltd., a Delaware corporation and a direct, wholly owned subsidiary of the Company. In connection with the closing of the GXII Transaction (the “GXII Closing”), pursuant to the Business Combination Agreement, the Company assumed GXII’s obligations under the Warrant Agreement, dated March 17, 2021 (the “GXII Warrant Agreement”), by and between GXII and Continental Stock Transfer & Trust Company (“CST”), as warrant agent, and each share purchase warrant of GXII thereunder (the “GXII Warrants”) that was issued and outstanding immediately prior to the March 17, 2023 was converted into one Warrant (the “NioCorp Assumed Warrants”) pursuant to the GXII Warrant Agreement, as amended by an Assignment, Assumption and Amendment Agreement, dated the March 17, 2023 (the GXII Warrant Agreement, as so amended, the “NioCorp Assumed Warrant Agreement”), among the Company, GXII, CST, as existing warrant agent, and Computershare Inc. and its affiliate Computershare Trust Company, N.A, together as successor warrant agent (the “NioCorp Assumed Warrant Agent”). In connection with the GXII Closing, NioCorp issued (a) 9,999,959 public NioCorp Assumed Warrants in respect of the GXII Warrants that were publicly traded prior to the GXII Closing and (b) 5,666,667 NioCorp Assumed Warrants to GX Sponsor II LLC (the “Sponsor”) in respect of the GXII Warrants that it held prior to the GXII Closing, which NioCorp Assumed Warrants were subsequently distributed by the Sponsor to its members in connection with the GXII Closing. Both the public NioCorp Assumed Warrants and the NioCorp Assumed Warrants issued to the Sponsor are subject to the terms of the NioCorp Assumed Warrant Agreement and are identical, with certain exceptions applicable to the NioCorp Assumed Warrants issued to the Sponsor for so long as such NioCorp Assumed Warrants are held by the Sponsor, its members, or their respective affiliates and other permitted transferees. In accordance with the NioCorp Assumed Warrant Agreement, any NioCorp Assumed Warrants issued to the Sponsor that are held by someone other than the Sponsor, its members, or their respective affiliates and other permitted transferees, are treated as public NioCorp Assumed Warrants.
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Each NioCorp Assumed Warrant is exercisable on and after April 16, 2023, until its expiration for 1.11829212 Common Shares at a price of $11.50 per 1.11829212 Common Shares (subject to adjustments for stock splits, stock dividends, reorganizations, recapitalizations and the like). Under the terms of NioCorp Assumed Warrant Agreement, for so long as the NioCorp Assumed Warrants issued to the Sponsor are held by the Sponsor, its members, or their respective affiliates and other permitted transferees, such holders have the right to elect to exercise those NioCorp Assumed Warrants on a cashless basis. For such NioCorp Assumed Warrants exercised on a cashless basis after the GXII Closing, the holder will be entitled to pay the exercise price for those NioCorp Assumed Warrants by surrendering all or portion of the cash and/or Common Shares (valued at their fair market value) into which those NioCorp Assumed Warrants are exercisable as shall be elected by the holder. For this purpose, Common Shares so surrendered will be deemed to have a “fair market value” equal to the average reported last sale price of the Common Shares for the 10 trading days ending on the third trading day prior to the date of exercise of the applicable NioCorp Assumed Warrants. The NioCorp Assumed Warrants will expire at 5:00 p.m., New York City time, on March 17, 2028, or earlier upon redemption or liquidation. The Company will not be obligated to deliver any Common Shares pursuant to the exercise of a NioCorp Assumed Warrant and will have no obligation to settle such exercise unless a registration statement under the Securities Act with respect to the Common Shares underlying the NioCorp Assumed Warrants is then effective and a prospectus relating thereto is current, subject to the Company satisfying its obligations described below with respect to registration. No NioCorp Assumed Warrant will be exercisable and the Company will not be obligated to issue Common Shares upon exercise of a NioCorp Assumed Warrant unless Common Shares issuable upon such exercise have been registered, qualified or deemed to be exempt under the securities laws of the state of residence of the registered holder of the NioCorp Assumed Warrants. In the event that the conditions in the two immediately preceding sentences are not satisfied with respect to a NioCorp Assumed Warrant, the holder of such NioCorp Assumed Warrant will not be entitled to exercise such NioCorp Assumed Warrant and such NioCorp Assumed Warrant may have no value and expire worthless. In no event will the Company be required to net cash settle any NioCorp Assumed Warrant. The NioCorp Assumed Warrants, and the underlying Common Shares issuable upon the exercise thereof, were registered under the Securities Act pursuant to the Company’s registration statement on Form S-4, originally filed on November 7, 2022, as subsequently amended, which was declared effective by the SEC on February 8, 2023. The ongoing registered offering of the Common Shares underlying the NioCorp Assumed Warrants is being conducted pursuant to the Company’s registration statement on Form S-3, originally filed on April 14, 2023, as subsequently post-effectively amended to convert such registration statement to Form S-1, which was declared effective on October 30, 2023. The Company will have the right to call the public NioCorp Assumed Warrants for redemption at any time following the March 17, 2023: • in whole and not in part; • at a price of $0.01 per NioCorp Assumed Warrant; • upon not less than 30 days’ prior written notice of redemption (the “30-day redemption period”) to each public NioCorp Assumed Warrant holder; • if, and only if, the reported last sale price of the Common Shares equals or exceeds approximately $16.10 per share (subject to certain adjustments) for any 20 trading days within a 30-trading day period commencing once the NioCorp Assumed Warrants become exercisable and ending three business days before the Company sends the notice of redemption to the public NioCorp Assumed Warrant holders; and • if there is an effective registration statement covering the Common Shares issuable upon exercise of the NioCorp Assumed Warrants, and a current prospectus relating thereto, available throughout the 30-day redemption period.
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The NioCorp Assumed Warrants issued to the Sponsor are not redeemable by the Company for so long as such NioCorp Assumed Warrants are held by the Sponsor, its members, or their respective affiliates or other permitted transferees. In addition, the Company may not exercise its redemption right if the issuance of Common Shares upon exercise of the NioCorp Assumed Warrants is not exempt from registration or qualification under applicable state blue sky laws or the Company is unable to effect such registration or qualification. If the Company calls the public NioCorp Assumed Warrants for redemption as described above, the Company will have the option to require any holder that wishes to exercise its public NioCorp Assumed Warrant to do so on a “cashless basis.” In determining whether to require all holders to exercise their public NioCorp Assumed Warrants on a “cashless basis,” the Company will consider, among other factors, its cash position, the number of NioCorp Assumed Warrants that are outstanding and the dilutive effect on the Company’s shareholders of issuing the maximum number of Common Shares issuable upon the exercise of the NioCorp Assumed Warrants. If the Company takes advantage of this option, all holders of public NioCorp Assumed Warrants would pay the exercise price by surrendering their NioCorp Assumed Warrants for that number of Common Shares equal to the quotient obtained by dividing (x) the product of the number of Common Shares underlying the public NioCorp Assumed Warrants, multiplied by the difference between the exercise price of the NioCorp Assumed Warrants and the “fair market value” (defined below) by (y) the fair market value. The “fair market value” shall mean the average reported last sale price of the Common Shares for the 10 trading days ending on the third trading day prior to the date on which the notice of redemption is sent to the holders of public NioCorp Assumed Warrants. If the Company takes advantage of this option, the notice of redemption will contain the information necessary to calculate the number of Common Shares to be received upon exercise of the NioCorp Assumed Warrants, including the “fair market value” in such case. Requiring a cashless exercise in this manner will reduce the number of Common Shares to be issued and thereby lessen the dilutive effect of a redemption of the public NioCorp Assumed Warrants. If the Company calls the public NioCorp Assumed Warrants for redemption and does not take advantage of this option, the Sponsor, its members, and their respective affiliates and other permitted transferees would still be entitled to exercise their NioCorp Assumed Warrants for cash or on a cashless basis using the same formula described above that other NioCorp Assumed Warrant holders would have been required to use had all NioCorp Assumed Warrant holders been required to exercise their NioCorp Assumed Warrants on a cashless basis, as described in more detail below. A holder of a NioCorp Assumed Warrant may notify the Company in writing in the event it elects to be subject to a requirement that such holder will not have the right to exercise such NioCorp Assumed Warrant, to the extent that after giving effect to such exercise, such holder (together with such holder’s affiliates), to the NioCorp Assumed Warrant Agent’s actual knowledge, would beneficially own in excess of 4.9% or 9.8% (or such other amount as a holder may specify) of the Common Shares outstanding immediately after giving effect to such exercise. The NioCorp Assumed Warrants have certain anti-dilution and adjustments rights upon certain events. The NioCorp Assumed Warrants may be exercised upon surrender of the certificate representing such NioCorp Assumed Warrants on or prior to the expiration date at the offices of the NioCorp Assumed Warrant Agent, with the exercise form on the reverse side of such certificate completed and executed as indicated, accompanied by full payment of the exercise price (or on a cashless basis, if applicable), by certified or official bank check payable to the order of the NioCorp Assumed Warrant Agent or by wire transfer, for the number of NioCorp Assumed Warrants being exercised. The NioCorp Assumed Warrant holders will not have the rights or privileges of holders of Common Shares or any attendant voting rights until they exercise their NioCorp Assumed Warrants and receive Common Shares. After the issuance of Common Shares upon exercise of the NioCorp Assumed Warrants, each holder will be entitled to one (1) vote for each Common Share held of record on all matters to be voted on by NioCorp shareholders. If, upon exercise of the NioCorp Assumed Warrants, a holder would be entitled to receive a fractional interest in a share, the Company will, upon exercise, round down to the nearest whole number of Common Shares to be issued to the NioCorp Assumed Warrant holder. The NioCorp Assumed Warrants were issued in registered form under the NioCorp Assumed Warrant Agreement. The NioCorp Assumed Warrant Agreement may be amended by the parties thereto without the consent of any registered holder (i) for the purpose of curing any ambiguity, or curing, correcting or supplementing any mistake, or adding or changing any other provisions with respect to matters or questions arising under NioCorp Assumed Warrant Agreement as the parties may deem necessary or desirable and that the parties deem shall not adversely affect the
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interest of the registered holders of the NioCorp Assumed Warrants, and (ii) to provide for the delivery of such kind and amount of Common Shares or other securities or property (including cash) receivable upon a reclassification, reorganization, merger or consolidation, or upon a dissolution following any such sale or transfer, that the holder of NioCorp Assumed Warrants would have received if such holder had exercised his, her or its NioCorp Assumed Warrants immediately prior to such event. All other modifications or amendments, including any amendment to increase the warrant price or shorten the exercise period, shall require the vote or written consent of the registered holders of a majority of the then outstanding public NioCorp Assumed Warrants. Any amendment solely to the NioCorp Assumed Warrants issued to the Sponsor and that are held by the Sponsor, its members, or their respective affiliates or other permitted transferees, shall require the vote or written consent of a majority of the holders of the then outstanding NioCorp Assumed Warrants issued to the Sponsor.
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EXHIBIT 10.14 EXECUTION VERSION EMPLOYMENT AGREEMENT THIS EMPLOYMENT AGREEMENT, by and between Elk Creek Resources Corporation, a corporation, with its principal place of business located at 386 Broadway, P.O. Box 506, Tecumseh, NE 68450, and any successor entity thereto (the “Company”), and Ernest Cleave (“Executive”), is dated as of the 1st day of July, 2026 (the “Agreement”). WHEREAS, the Company wishes to continue to employ Executive on the terms and conditions, and for the consideration, hereinafter set forth, and Executive desires to continue to be employed by the Company on such terms and conditions and for such consideration; and WHEREAS, concurrently with this Agreement, Executive is receiving a copy of the Restrictive Covenant Agreement attached hereto as Exhibit A (the “Restrictive Covenant Agreement”) which includes a covenant not to compete that could restrict Executive’s options with respect to subsequent employment following the termination of Executive’s employment from the Company (or an affiliate thereof); and WHEREAS, Executive shall have a period of fifteen (15) days from the date of this Agreement to review and execute the Restrictive Covenant Agreement. NOW THEREFORE, in consideration of the promises provided for in this Agreement, the Company and Executive agree as follows: 1.Employment Period. Subject to Executive’s execution of the Restrictive Covenant Agreement prior to the Effective Date (as defined below), this Agreement shall become effective upon execution. Except as otherwise provided in Section 3 of this Agreement, the Company hereby agrees to continue to employ Executive, and Executive hereby agrees to continue to be employed by the Company, on an at-will basis on the terms and conditions set forth herein for the period commencing on the Effective Date and ending on Executive’s Date of Termination (as defined in Section 3(f)) (the “Employment Period”). 2. Terms of Employment. (a) Position and Duties. (i)During the Employment Period, Executive shall (A) serve as the Senior Vice President Business Development of NioCorp with such duties and responsibilities as are customarily commensurate with or incident to such positions for entities similar in size to, and in a business similar to that of, NioCorp and the Company, respectively, (B) report to the Chief Executive Officer of NioCorp, and (C) perform Executive’s services at the Company’s principal place of business in Centennial, Colorado (subject to reasonable travel requirements commensurate with Executive’s position).
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(ii)During the Employment Period, and excluding any periods of vacation and sick leave to which Executive is entitled, Executive agrees to devote Executive’s full business time and attention to the business and affairs of the Company. During the Employment Period, it will not be a violation of this Agreement for Executive to (A) serve on civic or charitable boards or committees, (B) deliver lectures, fulfill speaking engagements or teach at educational institutions and (C) manage personal investments, so long as such activities described in clauses (A), (B) and (C) do not significantly interfere with the performance of Executive’s responsibilities as an employee of the Company in accordance with this Agreement. Executive shall not during the Employment Period serve as a director or executive of another corporation without the prior written approval of the Chief Executive Officer of NioCorp. (b) Compensation. (i)Base Salary. During the Employment Period, Executive shall receive an annual base salary (“Annual Base Salary”) of $275,000 paid in accordance with the normal payroll practices of the Company as may be in effect from time to time, which Annual Base Salary shall be reviewed for increase at least annually. (ii)Employee Benefits. During the Employment Period, Executive shall be eligible to participate in the employee benefit plans, programs, and policies, as may be in effect from time to time, for senior executives of the Company generally, including, but not limited to, any annual cash bonus plan and/or any annual long-term incentive compensation program as may be established by the Company. (iii)Expenses. During the Employment Period, Executive shall be entitled to receive prompt reimbursement for all reasonable expenses incurred by Executive in accordance with the performance of Executive’s duties under this Agreement and in accordance with the Company’s business expense reimbursement policy. 3. Termination of Employment. (a) Death or Disability. Executive’s employment shall terminate automatically if Executive dies during the Employment Period. If the Company determines in good faith that the Disability (as defined herein) of Executive has occurred during the Employment Period (pursuant to the definition of “Disability” set forth below), it may give to Executive written notice in accordance with Section 13(b) of its intention to terminate Executive’s employment. In such event, Executive’s employment with the Company shall terminate effective on the thirtieth (30th) day after receipt of such notice by Executive (the “Disability Effective Date”), provided that, within the thirty (30) days after such receipt, Executive shall not have returned to full-time performance of Executive’s duties. “Disability” means the absence of Executive from Executive’s duties with the Company on a full-time basis
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for ninety (90) consecutive business days, or ninety (90) business days during any period of one hundred and twenty (120) consecutive business days, as a result of incapacity due to mental or physical illness that is determined to be total and permanent by a physician selected by the Company or its insurers and acceptable to Executive or Executive’s legal representative (such agreement as to acceptability not to be unreasonably withheld). (b) By the Company. The Company may terminate Executive’s employment during the Employment Period for any, or no reason, with or without Cause. For purposes of this Agreement, “Cause” will be deemed to exist upon: (i)any use or misappropriation by Executive of the funds, assets or property of the Company, its parent, an affiliate or a subsidiary for any personal or other improper purpose; (ii)any act of moral turpitude, dishonesty, fraud by or felony conviction of Executive whether or not such acts were committed in connection with the business of the Company, an affiliate or a subsidiary; (iii)any failure by Executive substantially to perform the lawful instructions of the person(s) to whom Executive reports (other than as a result of total or partial incapacity due to physical or mental illness) following written notice by the Company to Executive of such failure and fifteen (15) days within which to cure such failure; (iv)any willful or gross misconduct by Executive in connection with Executive’s duties to the Company which, in the reasonable good faith judgment of the Board of Directors of NioCorp, could reasonably be expected to be materially injurious to the financial condition or business reputation of the Company, its subsidiaries or affiliates; (v)any failure by Executive to follow a material Company policy; (vi)any material breach by Executive of this Agreement; or (vii)any breach by Executive of the Restrictive Covenant Agreement. (c) By Executive. Executive’s employment may be terminated during the Employment Period by Executive for any reason. (d) Notice of Termination. Any termination of employment by the Company for Cause shall be communicated by Notice of Termination to Executive given in accordance with Section 13(b) of this Agreement. “Notice of Termination” means a written notice that (i) indicates the specific termination provision in this Agreement relied upon, (ii) to the extent applicable, sets forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of Executive’s employment under the provision so indicated, and (iii) if the Date of Termination (as defined herein) is other than the date of
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receipt of such notice, specifies the Date of Termination (which Date of Termination shall be not more than thirty (30) days after the giving of such notice). The failure by the Company to set forth in the Notice of Termination any fact or circumstance that contributes to a showing of Cause shall not waive any right the Company hereunder or preclude the Company from asserting such fact or circumstance in enforcing the Company’s rights hereunder. (e) Resignation. Upon any termination of Executive’s employment with the Company for any reason, Executive agrees to resign, as of the date of such termination and to the extent applicable, as an officer of the Company and/or any of the Company’s subsidiaries and other affiliates. (f) Date of Termination. “Date of Termination” means: (i) if Executive’s employment is terminated by the Company for Cause, the date of receipt of the Notice of Termination or such later date specified in the Notice of Termination, as the case may be, (ii) if Executive’s employment is terminated by the Company other than for Cause or Disability, the date on which the Company notifies Executive of such termination, (iii) if Executive resigns, the date on which Executive notifies the Company of such termination, and (iv) if Executive’s employment is terminated by reason of death or Disability, the date of Executive’s death or the Disability Effective Date, as the case may be. Notwithstanding the foregoing, in no event shall the Date of Termination occur until Executive experiences a “separation from service” within the meaning of Section 409A of the Internal Revenue Code of 1986, as amended (the “Code”), and the date on which such separation from service takes place shall be the “Date of Termination.” 4. Obligations of the Company upon Termination. (a) By the Company other than for Cause, Death or Disability. If, during the Employment Period, the Company terminates Executive’s employment without Cause (other than due to death or Disability), and Section 4(b) does not apply: (i)The Company shall pay to Executive, in a lump sum in cash within thirty (30) days after the Date of Termination (or earlier, if required by applicable law), the aggregate of the following amounts: the sum of: (A) Executive’s Annual Base Salary through the Date of Termination to the extent not theretofore paid; (B) Executive’s business expenses that are reimbursable pursuant to Section 2(b)(iii) of this Agreement but have not been reimbursed by the Company as of the Date of Termination; and (C) any accrued and unused vacation pay or paid time off to the extent not theretofore paid (the sum of the amounts described in subclauses (A), (B), and (C), the “Accrued Obligations”); (ii)Subject to Section 4(e) and Section 10(b), the Company shall continue to pay Executive the Annual Base Salary as in effect at the time of such termination for a period of twelve (12) months following such termination in
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accordance with the Company’s normal payroll practices; and (iii)To the extent not theretofore paid or provided, the Company shall timely pay or provide to Executive any Other Benefits (as defined in Section 5) in accordance with the terms of the underlying plans or agreements. Other than as set forth in this Section 4(a), in the event of a termination of Executive’s employment by the Company without Cause (other than due to death or Disability) and Section 4(b) does not apply, the Company shall have no further obligation to Executive under this Agreement. (b)Termination in Connection With a Change in Control. If, during the Employment Period, the Company terminates Executive’s employment without Cause (other than due to death or Disability) or Executive terminates employment for Good Reason (as defined below), in each case, within a period of two years after a Change in Control (as defined below) (such termination hereinafter referred to as a “Change in Control Termination”): (i)The Company shall pay to Executive, in a lump sum in cash within thirty (30) days after the Date of Termination, subject to Section 10(b), the Accrued Obligations; (ii)Subject to Section 10(b), on the sixty-first (61st) day after the Date of Termination, the Company shall, subject to Section 4(e), pay to Executive a lump sum cash amount equal to two (2) times Executive’s Annual Base Salary as in effect at the time of such termination (without regard to any reduction thereto); and (iii)To the extent not theretofore paid or provided, the Company shall timely pay or provide to Executive any Other Benefits (as defined in Section 5) in accordance with the terms of the underlying plans or agreements. Other than as set forth in this Section 4(b), in the event of a termination of Executive’s employment by the Company without Cause (other than due to death or Disability) (and Section 4(a) does not apply) or by Executive for Good Reason, in each case, within a period of two (2) years after a Change in Control, the Company shall have no further obligation to Executive under this Agreement. (c)Death or Disability. If Executive’s employment is terminated by reason of Executive’s death or Disability during the Employment Period, the Company shall provide Executive or, in the event of death, Executive’s estate or beneficiaries, with the Accrued Obligations and the timely payment or delivery of the Other Benefits in accordance with the terms of the underlying plans or agreements, and shall have no further obligations under this Agreement. The Accrued Obligations shall be paid to Executive or, in the event of death, Executive’s estate or beneficiaries, in a lump sum in cash within thirty (30) days of the applicable Date of Termination. (d)Cause; Other than for Good Reason Following a Change in Control. If Executive’s employment is terminated for Cause during the Employment Period, the Company shall provide
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Executive with Executive’s Annual Base Salary through the Date of Termination, and the timely payment or delivery of the Other Benefits in accordance with the terms of the underlying plans or agreements, and shall have no further obligations under this Agreement. If Executive voluntarily terminates employment for any reason (other than for Good Reason within two (2) years after a Change in Control as provided in Section 4(b)) during the Employment Period, the Company shall provide to Executive the Accrued Obligations and the timely payment or delivery of the Other Benefits in accordance with the terms of the underlying plans or agreements, and shall have no further obligations under this Agreement. In such case, all the Accrued Obligations shall be paid to Executive in a lump sum in cash within thirty (30) days of the Date of Termination. (e)Release. Notwithstanding anything herein to the contrary, the Company shall not be obligated to make any payment under Sections 4(a)(ii) or 4(b)(ii) of this Agreement unless (i) prior to the sixtieth (60th) day following the Date of Termination, Executive executes a release of claims against the Company and its affiliates in a form provided by the Company (the “Release”), and (ii) any applicable revocation period has expired during such sixty (60)-day period without Executive revoking such Release. (f)Definition of Change in Control. For purposes of this Agreement, a “Change in Control” will be deemed to have occurred upon the occurrence (after the Effective Date) of any transaction that constitutes a “change in ownership,” a “change in effective control,” or a “change in the ownership of a substantial portion of the assets” of the Company under Section 409A(a)(2)(A)(v) of the Code. (g)Definition of Good Reason. For purposes of this Agreement, “Good Reason” shall mean, in the absence of the prior written consent of Executive: (i) a material reduction of Executive’s Annual Base Salary; (ii) relocation of Executive’s primary workplace, as assigned to Executive by the Company in accordance with Section 2(a)(i)(C) beyond a 50 mile radius from such workplace; or (iii) any other material breach by the Company of this Agreement; provided, however, that Executive’s termination of employment shall not be deemed to be for Good Reason unless (A) Executive has notified the Company in writing describing the occurrence of one or more Good Reason events within ninety (90) days of such occurrence, (B) the Company fails to cure such Good Reason event within thirty (30) days after its receipt of such written notice and (C) the termination of employment occurs within one hundred and eighty (180) days after the occurrence of the applicable Good Reason event. 5.Non-Exclusivity of Rights. Amounts that Executive is otherwise entitled to receive under any plan, policy, practice or program of or any other contract or agreement with the
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Company at or subsequent to the Date of Termination (“Other Benefits”) shall be payable in accordance with such plan, policy, practice or program or contract or agreement, except as explicitly modified by this Agreement. Notwithstanding the foregoing, Executive shall not be eligible to participate in any other severance plan, program or policy of the Company. 6.Set-off; No Mitigation. The Company’s obligation to make the payments provided for in this Agreement and otherwise to perform its obligations hereunder shall be subject to set- off, counterclaim, recoupment, defense, or other claim, right or action that the Company may have against Executive to the extent such set-off or other action does not violate Section 409A of the Code. In no event shall Executive be obligated to seek other employment or take any other action by way of mitigation of the amounts payable to Executive under any of the provisions of this Agreement; provided, however, that it is expressly understood that the Company’s payment obligations under Sections 4(a)(ii) and 4(b)(ii) of this Agreement shall cease in the event Executive breaches any of the terms contained in the Restrictive Covenant Agreement. 7.Limitations on Payments Under Certain Circumstances. Notwithstanding any provision of any other plan, program, arrangement or agreement to the contrary, in the event that it shall be determined that any payment or benefit to be provided by the Company to Executive pursuant to the terms of this Agreement or any other payments or benefits received or to be received by Executive (a “Payment”) in connection with or as a result of any event which is deemed by the U.S. Internal Revenue Service or any other taxing authority to constitute a change in the ownership or effective control of the Company, or in the ownership of a substantial portion of the assets of the Company and subject to the tax (the “Excise Tax”) imposed by Section 4999 (or any successor section) of the Code, the Payments, whether under this Agreement or otherwise, shall be reduced so that the Payment, in the aggregate, is reduced to the greatest amount that could be paid to Executive without giving rise to any Excise Tax; provided that in the event that Executive would be placed in a better after-tax position after receiving all Payments and not having any reduction of Payments as provided hereunder, Executive shall, notwithstanding the provisions of any other plan, program, arrangement or agreement to the contrary, receive all Payments and pay any applicable Excise Tax. All determinations under this Section 7 shall be made by a nationally recognized accounting firm selected by the Company (the “Accounting Firm”). Without limiting the generality of the foregoing, any determination by the Accounting Firm under this Section 7 shall take into account the value of any reasonable compensation for services to be rendered by Executive (or for holding oneself out as available to perform services and refraining from performing services (such as under a covenant not to compete)). If the Payments are to be reduced pursuant to this Section 7, the Payments shall be reduced in the following order: (a) Payments which do not constitute “nonqualified deferred compensation” subject to Section 409A of the Code shall be reduced first; and (b) all other Payments shall then be reduced, in each case as follows: (i) cash payments shall be reduced before non-cash payments and (ii) payments to be made on a later payment date shall be reduced before payments to be made on an earlier payment date. 8. Successors.
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(a)This Agreement is personal to Executive and without the prior written consent of the Company shall not be assignable by Executive otherwise than by will or the laws of descent and distribution. This Agreement shall inure to the benefit of, and be enforceable by, Executive’s legal representatives. (b)This Agreement shall inure to the benefit of and be binding upon the Company and its successors and assigns. As set forth in the preamble, as used in this Agreement, “Company” shall mean the Company as hereinbefore defined and any successor to its business and/or assets as aforesaid which assumes and agrees to perform this Agreement by operation of law, or otherwise. 9.Indemnification. The Company shall indemnify Executive to the maximum extent permitted under applicable law for acts taken within the scope of Executive’s employment and Executive’s service as an officer or director of the Company or any of its subsidiaries or affiliates. To the extent that the Company obtains coverage under a director and officer indemnification policy, Executive will be entitled to such coverage on a basis that is no less favorable than the coverage provided to any other officer or director of the Company. 10. Section 409A of the Code. (a)The intent of the parties is that payments and benefits under this Agreement comply with, or be exempt from, Section 409A of the Code and the regulations and guidance promulgated thereunder (collectively “Section 409A”) and, accordingly, to the maximum extent permitted, this Agreement shall be interpreted to be in compliance therewith. (b)Notwithstanding any provision of this Agreement to the contrary, in the event that Executive is a “specified employee” within the meaning of Section 409A (as determined in accordance with the methodology established by the Company as in effect on the Date of Termination) (a “Specified Employee”), any payments or benefits that are considered non- qualified deferred compensation under Section 409A payable under this Agreement on account of a “separation from service” during the six-month period immediately following the Date of Termination shall, to the extent necessary to comply with Section 409A, instead be paid, or provided, as the case may be, on the first business day after the date that is six months following Executive’s “separation from service” within the meaning of Section 409A. For purposes of Section 409A, Executive’s right to receive any installment payments pursuant to this Agreement shall be treated as a right to receive a series of separate and distinct payments. In no event may Executive, directly or indirectly, designate the calendar year of any payment to be made under this Agreement that is considered nonqualified deferred compensation, subject to Section 409A. (c)With regard to any provision herein that provides for reimbursement of costs and expenses or in-kind benefits that are deferred compensation subject to Section 409A, (i) the right to reimbursement or in-kind benefits shall not be subject to liquidation or exchange for another benefit, (ii) the amount of expenses eligible for reimbursement, or in-kind benefits, provided during any taxable year shall not affect the expenses eligible for reimbursement, or in-kind benefits to be provided, in any other taxable year and (iii) such payments shall be made on or before the last day of Executive’s taxable year following the taxable year in which the expense occurred.
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11.Compensation Recovery Policy. Notwithstanding anything in this Agreement to the contrary, Executive acknowledges and agrees that this Agreement and any compensation described herein are subject to the terms and conditions of the Company’s clawback policy (if any) as may be in effect from time to time, including specifically to implement Section 10D of the Securities Exchange Act of 1934, as amended, and any applicable rules or regulations promulgated thereunder (including applicable rules and regulations of any national securities exchange on which the shares of the Company’s common stock may be traded) (the “Compensation Recovery Policy”), and that applicable sections of this Agreement and any related documents shall be deemed superseded by and subject to the terms and conditions of the Compensation Recovery Policy from and after the effective date thereof. 12.Complete Agreement. This Agreement sets forth the entire agreement of the parties hereto in respect of the subject matter contained herein, and supersedes all prior agreements, promises, covenants, arrangements, communications, representations or warranties, whether oral or written, by any officer, employee or representative of any party hereto in respect of the subject matter contained herein. 13. Miscellaneous. (a)This Agreement shall be governed by and construed in accordance with the laws of the State of Colorado, without reference to principles of conflict of laws. Executive agrees that the state and federal courts located in the State of Colorado shall have jurisdiction in any action, suit or proceeding against Executive based on or arising out of this Agreement and Executive hereby: (i) submits to the personal jurisdiction of such courts; (ii) consents to service of process in connection with any action, suit or proceeding against Executive; and (iii) waives any other requirement (whether imposed by statute, rule of court or otherwise) with respect to personal jurisdiction, venue or service of process. The captions of this Agreement are not part of the provisions hereof and shall have no force or effect. This Agreement may not be amended or modified otherwise than by a written agreement executed by the parties hereto or their respective successors and legal representatives. (b)All notices and other communications hereunder shall be in writing and shall be given by hand delivery to the other party or by registered or certified mail, return receipt requested, or nationally-recognized overnight courier service, postage prepaid, addressed as follows: If to Executive: At the most recent address on file at the Company. If to the Company: 7000 South Yosemite Street, Suite 115 Centennial, CO 80112 or such other address as either party shall have furnished to the other in writing in accordance herewith (including via electronic mail). Notice and communications shall be effective when actually received by the addressee. (c)The invalidity or unenforceability of any provision of this Agreement shall not
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affect the validity or enforceability of any other provision of this Agreement. (d)The Company, its subsidiaries and affiliates may withhold from any amounts payable under this Agreement such Federal, state, local or foreign taxes or social security charges as shall be required to be withheld pursuant to any applicable law or regulation. None of the Company, its subsidiaries or affiliates guarantees any tax result with respect to payments or benefits provided hereunder. Executive is responsible for all taxes owed with respect to all such payments and benefits. (e)Subject to any limits on applicability contained therein, the Restrictive Covenant Agreement shall survive and continue in full force in accordance with its terms notwithstanding any termination or expiration of the Employment Period. (f)During Executive’s employment with the Company and thereafter, Executive will provide reasonable assistance to the Company in litigation and regulatory matters that relate to events that occurred during Executive’s period of employment with the Company and its predecessors, and will provide reasonable assistance to the Company with matters relating to its corporate history from the period of Executive’s employment with it or its predecessors. Executive will be entitled to reimbursement of reasonable out-of-pocket travel or related costs and expenses relating to any such cooperation or assistance that occurs following the Date of Termination. (g)This Agreement may be executed in several counterparts, each of which shall be deemed to be an original but all of which together will constitute one and the same instrument. (h)Executive’s or the Company’s failure to insist upon strict compliance with any provision of this Agreement or the failure to assert any right Executive or the Company may have hereunder shall not be deemed to be a waiver of such provision or right or any other provision or right of this Agreement. (i)With respect to any controversy or claim arising out of or relating to or concerning injunctive relief for Executive’s breach or purported breach of the Restrictive Covenant Agreement, the Company shall have the right, in addition to any other remedies it may have, to seek specific performance and injunctive relief with a court of competent jurisdiction, without the need to post a bond or other security. 14.Other Acknowledgements. Nothing in this Agreement prevents Executive from providing, without prior notice to the Company, information to governmental authorities regarding possible legal violations or otherwise testifying or participating in any investigation or proceeding by any governmental authorities regarding possible legal violations. [Remainder of page intentionally left blank]
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IN WITNESS WHEREOF, Executive and the Company have executed this Agreement on the date first above written. EXECUTIVE /s/ Ernest Cleave Ernest Cleave ELK CREEK RESOURCES CORPORATION By /s/ Mark Smith Name: Mark Smith Title: Chief Executive Officer
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Exhibit A Restrictive Covenant Agreement (See attached.)
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13 RESTRICTIVE COVENANT AGREEMENT THIS RESTRICTIVE COVENANT AGREEMENT (this “Agreement”) is made and entered into as of July 1, 2026 by and between Elk Creek Resources Corporation, a Delaware corporation, with its principal place of business located at 386 Broadway, P.O. Box 506, Tecumseh, NE 68450, and any successor entity thereto (the “Company”), and Ernest Cleave (“Executive”). This Agreement shall become effective upon execution. In consideration of the mutual covenants contained herein and other good and valuable consideration (including as set forth in the Employment Agreement between the Company and Executive dated as of July 1, 2026 (the “Employment Agreement”)), the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows: 1. Competitive Activity; Confidentiality; Nonsolicitation. (a)Acknowledgements and Agreements. Executive hereby acknowledges and agrees that in the performance of Executive’s duties to the Company during the Employment Period (as defined in the Employment Agreement), Executive shall be brought into frequent contact with existing and potential customers of the Company throughout the world. Executive also agrees that trade secrets and confidential information of the Company, more fully described in Section 1(h) gained by Executive during Executive’s association with the Company, have been developed by the Company through substantial expenditures of time, effort and money and constitute valuable and unique property of the Company. Executive further understands and agrees that the foregoing makes it necessary for the protection of the Company’s business that Executive not compete with the Company during Executive’s employment with the Company and not compete with the Company for a reasonable period thereafter, as further provided in the following sections. (b) Covenants. (i) Covenants During Employment. Except for permitted activities expressly approved by the Board, while employed by the Company, Executive will not compete with the Company anywhere in the world. In accordance with this restriction, but without limiting its terms, while employed by the Company, Executive will not: (A) enter into or engage in any business which competes with the Company’s business; (B) solicit customers, business, patronage or orders for, or sell, any products or services in competition with, or for any business that competes with, the Company’s business; divert, entice or otherwise take away any customers, business, patronage or orders of the Company or attempt to do so; or (C) promote or assist, financially or otherwise, any person, firm, association, partnership, corporation or other entity engaged in any business which competes with the Company’s business.
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14 (ii) Covenants Following Termination. For a period of (x) one (1) year following the date of termination of Executive’s employment with the Company for any reason other than a Change in Control Termination (as such term is defined in the Employment Agreement) or (y) two (2) years following the date of termination of Executive’s employment with the Company in the event of a Change in Control Termination (such period of time, the “Post-Termination Restricted Period”), Executive will not: (A) enter into or engage in any business which competes with the Company’s Business within the Restricted Territory (as hereinafter defined); (B) solicit customers, business, patronage or orders for, or sell, any products or services in competition with, or for any business, wherever located, that competes with, the Company’s Business within the Restricted Territory; (C) divert, entice or otherwise take away any customers, business, patronage or orders of the Company within the Restricted Territory, or attempt to do so; or (D) promote or assist, financially or otherwise, any person, firm, association, partnership, corporation or other entity engaged in any business which competes with the Company’s Business within the Restricted Territory. (iii) Indirect Competition. For the purposes of Sections 1(a) and (b) above, inclusive, but without limitation thereof, Executive will be in violation thereof if Executive engages in any or all of the activities set forth therein directly as an individual on Executive’s own account, or indirectly as a partner, joint venturer, employee, agent, salesperson, consultant, officer and/or director of any firm, association, partnership, corporation or other entity, or as a stockholder of any corporation in which Executive or Executive’s spouse, child or parent owns, directly or indirectly, individually or in the aggregate, more than 5% of the outstanding stock. (c)The “Company.” For purposes of this Section 1, the “Company” shall include any and all direct and indirect subsidiaries, parents, and affiliated, or related companies of the Company for which Executive worked or had responsibility, or with respect to which Executive had access to trade secrets or confidential information at the time of termination of Executive’s employment and at any time during the two (2) year period prior to such termination. (d)The Company’s “Business.” For the purposes of this Section 1, the Company’s “Business” is defined to be the acquisition, exploration, and development of mineral properties, as further described in any and all manufacturing, marketing and sales manuals and materials of the Company as the same may be altered, amended, supplemented or otherwise changed from time to
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15 time, or of any other products or services substantially similar to or readily substitutable for any such described products and services. (e)“Restricted Territory.” For purposes of Section 1, the Restricted Territory shall be defined as and limited to: (i) the geographic area(s) within a 100 mile radius of any and all of the Company’s location(s) in, to, or for which Executive worked, to which Executive was assigned or had any responsibility (either direct or supervisory) at the time of termination of Executive’s employment and at any time during the two-year period prior to such termination; (ii) the United States; and (iii) all of the specific customer accounts, whether within or outside of the geographic area described in (i) and (ii) above, with which Executive had any contact or for which Executive had any responsibility (either direct or supervisory) at the time of termination of Executive’s employment and at any time during the two-year period prior to such termination. (f) Extension. If it shall be judicially determined that Executive has violated any of Executive’s obligations under Section 1(b), then the period applicable to each obligation that Executive shall have been determined to have violated shall automatically be extended by a period of time equal in length to the period during which such violation(s) occurred. (g)Non-Solicitation. Executive will not directly or indirectly at any time during the period of Executive’s employment or thereafter, attempt to disrupt, damage, impair or interfere with the Company’s business by raiding any of the Company’s employees or soliciting any of them to resign from their employment with the Company, or by disrupting the relationship between the Company and any of its consultants, agents or representatives. Executive acknowledges that this covenant is necessary to enable the Company to maintain a stable workforce and remain in business. (h) Further Covenants. (i) Executive will keep in strict confidence and shall not, directly or indirectly, at any time during or after Executive’s employment with the Company, disclose, furnish, disseminate, make available or, except in the course of performing Executive’s duties of employment, use any trade secrets or confidential business and technical information of the Company or its customers or vendors, without limitation as to when or how Executive may have acquired such information. Such confidential information shall include, without limitation, the Company’s unique selling, manufacturing and servicing methods and business techniques, training, service and business manuals, promotional materials, training courses and other training and instructional materials, vendor and product information, customer and prospective customer lists, other customer and prospective customer information, employee evaluation and employee performance information, and other business information. Executive specifically acknowledges that all such confidential information, whether reduced to writing,
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16 maintained on any form of electronic media, or maintained in Executive’s mind or memory and whether compiled by the Company, and/or Executive, derives independent economic value from not being readily known to or ascertainable by proper means by others who can obtain economic value from its disclosure or use, that reasonable efforts have been made by the Company to maintain the secrecy of such information, that such information is the sole property of the Company and that any retention and use of such information by Executive during Executive’s employment with the Company (except in the course of performing Executive’s duties and obligations to the Company) or after the termination of Executive’s employment shall constitute a misappropriation of the Company’s trade secrets. The restrictions set forth in this Section 1(h) shall be perpetual for all confidential information that is a trade secret, or for so long as the information remains a trade secret under applicable law. The restrictions set forth in this Section 1(h) shall last for ten (10) years after termination, for all other forms of confidential information. (ii) Executive agrees that upon termination of Executive’s employment with the Company for any reason, Executive shall return to the Company, in good condition, all property of the Company, including without limitation, the originals and all copies of any materials which contain, reflect, summarize, describe, analyze or refer or relate to any items of information listed in this Section 1(h) of this Agreement. In the event that such items are not so returned, the Company will have the right to charge Executive for all reasonable damages, costs, attorneys’ fees and other expenses incurred in searching for, taking, removing and/or recovering such property. (iii) The U.S. Defend Trade Secrets Act of 2016 (“DTSA”) provides that an individual shall not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that (A) is made in confidence to a federal, state or local government official, either directly or indirectly, or to an attorney, and solely for the purpose of reporting or investigating a suspected violation of law; or (B) is made in a complaint or other document filed in a lawsuit or other proceeding, if such filing is made under seal. In addition, the DTSA provides that an individual who files a lawsuit for retaliation by an employer for reporting a suspected violation of law may disclose the trade secret to the attorney of the individual and use the trade secret information in the court proceeding, if the individual files any document containing the trade secret under seal and does not disclose the trade secret, except pursuant to court order. (i) Discoveries and Inventions; Work Made for Hire. (i) During the period of Executive’s employment Executive agrees that upon conception and/or development of any idea, discovery, invention, improvement, software, writing or other material or design that (A) relates to the business of the Company, or (B) relates to the Company’s actual or demonstrably anticipated research or development, or (C) results from any work performed by Executive for the Company, Executive hereby assigns to the Company the entire right, title and interest in and to any such idea,
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17 discovery, invention, improvement, software, writing or other material or design. Executive has no obligation to assign any idea, discovery, invention, improvement, software, writing or other material or design that Executive conceives and/or develops entirely on Executive’s own time without using the Company’s equipment, supplies, facilities, or trade secret information unless the idea, discovery, invention, improvement, software, writing or other material or design either: (x) relates to the business of the Company, or (y) relates to the Company’s actual or demonstrably anticipated research or development, or (z) results from any work performed by Executive for the Company. Executive agrees that any idea, discovery, invention, improvement, software, writing or other material or design that relates to the business of the Company or relates to the Company’s actual or demonstrably anticipated research or development which is conceived or suggested by Executive, either solely or jointly with others, within one (1) year following termination of Executive’s employment shall be presumed to have been so made, conceived or suggested in the course of such employment with the use of the Company’s equipment, supplies, facilities, and/or trade secrets. (ii) In order to determine the rights of Executive and the Company in any idea, discovery, invention, improvement, software, writing or other material, and to insure the protection of the same, Executive agrees that during Executive’s employment, and for one (1) year after termination of Executive’s employment Executive will disclose immediately and fully to the Company any idea, discovery, invention, improvement, software, writing or other material or design conceived, made or developed by Executive solely or jointly with others. The Company agrees to keep any such disclosures confidential. Executive also agrees to record descriptions of all work in the manner directed by the Company and agrees that all such records and copies, samples and experimental materials will be the exclusive property of the Company. Executive agrees that at the request of and without charge to the Company, but at the Company’s expense, Executive will execute a written assignment of the idea, discovery, invention, improvement, software, writing or other material or design to the Company and will assign to the Company any application for letters patent or for trademark registration made thereon, and to any common-law or statutory copyright therein; and that Executive will do whatever may be necessary or desirable to enable the Company to secure any patent, trademark, copyright, or other property right therein in the United States and in any foreign country, and any division, renewal, continuation, or continuation in part thereof, or for any reissue of any patent issued thereon. In the event the Company is unable, after reasonable effort, and in any event after ten (10) business days, to secure Executive’s signature on a written assignment to the Company of any application for letters patent or to any common-law or statutory copyright or other property right therein, whether because of Executive’s physical or mental incapacity or for any other reason whatsoever, Executive irrevocably designates and appoints the Corporate Secretary of the Company as Executive’s attorney-in-fact to act on Executive’s behalf to execute and file any such application and to do all other lawfully permitted acts to further the prosecution and issuance of such letters
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18 patent, copyright or trademark. (iii) Executive acknowledges that, to the extent permitted by law, all work papers, reports, documentation, drawings, photographs, negatives, tapes and masters therefor, prototypes and other materials (hereinafter, “items”), including without limitation, any and all such items generated and maintained on any form of electronic media, generated by Executive during Executive’s employment with the Company will be considered a “work made for hire” and that ownership of any and all copyrights in any and all such items will belong to the Company. The item shall recognize the Company as the copyright owner, will contain all proper copyright notices, e.g., “(creation date) NioCorp Developments Ltd., All Rights Reserved,” and shall be in condition to be registered or otherwise placed in compliance with registration or other statutory requirements throughout the world. (j) Non-Disparagement. (i)Throughout Executive’s employment with the Company and during the Post-Termination Restricted Period, outside the ordinary course of business on behalf of the Company, Executive will not make or issue, or procure any person, firm, or entity to make or issue, any statement in any form, including written, oral and electronic communications of any kind, which conveys negative or adverse information concerning the Company or its subsidiaries or affiliates, or any of their legal predecessors, successors, assigns, parents, subsidiaries, divisions or other affiliates, or any of the foregoing’s respective past, present or future directors, officers, employees or representatives (collectively, the “Non-Disparagement Parties”), or any Non-Disparagement Party’s business, or its actions, to any person or entity, regardless of the truth or falsity of such statement. Throughout Executive’s employment with the Company and during the Post-Termination Restricted Period, the Company will reasonably direct the executive officers and directors of the Company not make or issue, or procure any person, firm, or entity to make or issue, any statement in any form, including written, oral and electronic communications of any kind, which conveys negative or adverse information concerning Executive or any of Executive’s legal successors, assigns, or other affiliates, or any of the foregoing’s respective past, present or future directors, officers, employees or representatives (collectively, the “Executive Non-Disparagement Parties”), or any Executive Non- Disparagement Party’s business, or its actions, to any person or entity, regardless of the truth or falsity of such statement. (ii)This Section 1(j) does not apply to truthful testimony or disclosure compelled or required by applicable law or legal process. Notwithstanding anything in this Agreement to the contrary, Executive is not prohibited from providing information voluntarily to the Securities and Exchange Commission pursuant to Section 21F of the Securities Exchange Act of 1934, as amended. (k)Communication of Contents of Agreement. While employed by the Company and for two (2) years thereafter, Executive will communicate the contents of Section 1 of this Agreement to any person, firm, association, partnership, corporation or other entity that Executive intends to be employed by, associated with, or represent.
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19 (l) Confidentiality Agreements. Executive agrees that Executive shall not disclose to the Company or induce the Company to use any secret or confidential information belonging to Executive’s former employers. Executive warrants that Executive is not bound by the terms of a confidentiality agreement or other agreement with a third party that would preclude or limit Executive’s right to work for the Company and/or to disclose to the Company any ideas, inventions, discoveries, improvements or designs or other information that may be conceived during employment with the Company. Executive agrees to provide the Company with a copy of any and all agreements with a third party that preclude or limit Executive’s right to make disclosures or to engage in any other activities contemplated by Executive’s employment with the Company. (m)Remedies. The parties acknowledge and agree that any breach by Executive of the terms of this Agreement may cause the Company irreparable harm and injury for which money damages would be inadequate. Accordingly, the Company, in addition to any other remedies available at law or equity, shall be entitled, as a matter of right, to injunctive relief in any court of competent jurisdiction. The parties agree that such injunctive relief may be granted without the necessity of proving actual damages. Nothing in this Agreement shall limit the Company’s remedies under state for federal law or elsewhere. (n)Reasonableness. Executive acknowledges and agrees that Executive received the notice required by Colo. Rev. Stat. Ann. § 8-2-113. Executive acknowledges that Executive’s obligations under this Section 1 are reasonable in the context of the nature of the Company’s business and the competitive injuries likely to be sustained by the Company if Executive were to violate such obligations and that these obligations do not place an undue burden on Executive. Executive further acknowledges that this Agreement is made in consideration of, and is adequately supported by the agreement of the Company to perform its obligations under this Agreement and by other consideration, including Executive’s continued employment with the Company, which Executive acknowledges constitutes good, valuable and sufficient consideration. It is the desire and intent of the parties hereto that the provisions of this Agreement shall be enforced to the fullest extent legally-permissible. Accordingly, if any particular provision(s) of this Agreement shall be adjudicated to be invalid or unenforceable, the court may modify or sever such provision(s), such modification or deletion to apply only with respect to the operation of such provision(s) in the particular jurisdiction in which such adjudication is made. In addition, if any one or more of the provisions contained in this Agreement shall for any reason be held to be excessively broad as to duration, geographical scope, activity or subject, it shall be construed by limiting and reducing it, so as to be enforceable to the extent compatible with the applicable law as it shall then appear. The remaining provisions of this Agreement shall remain in full force and effect. 2. Choice of Law. This Agreement shall be governed by, and construed in accordance with, the internal, substantive laws of the State of Colorado. Executive agrees that the state and federal courts located in the State of Colorado shall have jurisdiction in any action, suit or proceeding against Executive based on or arising out of this Agreement and Executive hereby: (a) submits to the personal jurisdiction of such courts; (b) consents to service of process in connection with any action, suit or proceeding against Executive; and (c) waives any other requirement (whether imposed by statute, rule of court or otherwise) with respect to personal jurisdiction, venue or service of process. 3. Notices. Any notice provided to the Company provided for in this Agreement shall be in writing to the Company, marked Attention: Corporate Secretary, and any notice to Executive shall be addressed to said Executive at Executive’s address on file with the Company.
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20 Except as otherwise provided herein, any written notice shall be deemed to be duly given if and when delivered personally or deposited in the United States mail, first class registered mail, postage and fees prepaid, and addressed as aforesaid. Any party may change the address to which notices are to be given hereunder by written notice to the other party as herein specified (provided that for this purpose any mailed notice shall be deemed given on the third business day following deposit of the same in the United States mail). 4. Headings. The headings herein have been inserted for convenience only and shall not be deemed to limit or otherwise affect any of the provisions of this Agreement. 5. Counterparts; Effectiveness. This Agreement may be executed in one or more counterparts (including counterparts transmitted by facsimile or Adobe PDF attached to an email), each of which shall be deemed an original and all of which shall constitute one and the same agreement. The exchange of copies of this Agreement and executed signature pages hereto by facsimile or in Adobe PDF attached to an email shall constitute effective execution and delivery of this Agreement and may be used in lieu of the original Agreement for all purposes. 6. Amendment and Waiver. The provisions of this Agreement may be amended or waived only with the prior written consent of the Company and Executive, and no course of conduct or failure or delay in enforcing the provisions of this Agreement shall affect the validity, binding effect or enforceability of this Agreement. 7. Complete Agreement. This Agreement and the Employment Agreement embody the complete agreement and understanding between the parties with respect to the subject matter hereof and shall supersede all other agreements or arrangements between the parties with regard to the subject matter hereof and effective as of their dates supersede and preempt any prior understandings, agreements or representations by or between the parties, written or oral, which may have related to the subject matter hereof in any way. Notwithstanding the foregoing, this Agreement does not supersede or in any way limit or otherwise affect any restrictive covenants to which Executive may be bound, pursuant to another agreement or otherwise. Those restrictive covenants would be enforceable separately in accordance with their terms. 8. Prevailing Party’s Litigation Expenses. In the event of litigation between the Company and Executive related to this Agreement, the non-prevailing party shall reimburse the prevailing party for any costs and expenses (including, without limitation, attorneys’ fees) reasonably incurred by the prevailing party in connection therewith. 9. Successors and Assigns. This Agreement shall bind and inure to the benefit of and be enforceable by Executive, the Company and their respective heirs, executors, personal representatives, successors and assigns by merger or consolidation, except that Executive may not assign any rights or delegate any obligations hereunder without the prior written consent of the Company. As set forth in the preamble, as used in this Agreement, “Company” shall mean the Company as hereinbefore defined and any successor to the Company by merger or consolidation or purchase of all or substantially all of the Company’s assets which assumes the liabilities of the Company hereunder. Executive hereby consents to the assignment by the Company of all of its rights and obligations hereunder to any successor to the Company by merger or consolidation or purchase of all or substantially all of the Company’s assets, provided such transferee or successor assumes the liabilities of the Company hereunder.
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21 10. Severability. Whenever possible, each provision of this Agreement shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Agreement is held to be invalid or unenforceable in any respect under any applicable law, such invalidity or unenforceability shall not affect any other provision, but this Agreement shall be reformed, construed and enforced as if such invalid or unenforceable provision had never been contained herein. 11. Other Acknowledgements. Nothing in this Agreement prevents Executive from providing, without prior notice to the Company, information to governmental authorities regarding possible legal violations or otherwise testifying or participating in any investigation or proceeding by any governmental authorities regarding possible legal violations. [Remainder of page intentionally left blank]
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IN WITNESS WHEREOF, Executive and the Company have executed this Agreement on the date first above written. EXECUTIVE /s/ Ernest Cleave Ernest Cleave ELK CREEK RESOURCES CORPORATION By /s/ Mark Smith Name: Mark Smith Title: Chief Executive Officer
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EXHIBIT 10.17 NIOCORP DEVELOPMENTS LTD. Long Term Incentive Plan Option Certificate This Certificate is issued pursuant to the provisions of the NioCorp Developments Ltd. (the “Issuer”) Long Term Incentive Plan (the “Plan”) and evidences that [NAME] is the holder (the “Option Holder”) of an option (the “Option”) to purchase up to [# Options] Common shares (the “Shares”) in the capital stock of the Issuer at a purchase price of US$[0.00] per Share. Subject to the provisions of the Plan: (a) the Award Date of this Option is [DATE]; (b) the Expiry Date of this Option is [DATE]; (c) this Option vests upon the following schedule (i) (ii) (iii) (d) this is an [ Incentive Stock Options (ISO) / Non-Qualified Option (NQO) ]; and (e) this Option terminates 90 days after the Option Holder ceases to be an eligible person to receive Options under the Plan. This Option may be exercised at any time and from time to time from and including the Award Date through to and including up to 4:30 local time in Denver, Colorado on the Expiry Date by delivery to the Administrator of the Plan an Exercise Notice, in the form provided in the Plan, together with this Certificate and a certified cheque or bank draft payable to “NioCorp Developments Ltd.” in an amount equal to the aggregate of the Exercise Price of the Shares in respect of which this Option is being exercised. This Certificate and the Option evidenced hereby is not assignable, transferable or negotiable and is subject to the detailed terms and conditions contained in the Plan, the terms and conditions of which the Option Holder hereby expressly agrees with the Issuer to be bound by. This Certificate is issued for convenience only and in the case of any dispute with regard to any matter in respect hereof, the provisions of the Plan and the records of the Issuer shall prevail. The foregoing Option has been awarded this [X] day of [MONTH YEAR]. NIOCORP DEVELOPMENTS LTD. Per: _____________ Administrator, Stock Option Plan NioCorp Developments Ltd.
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Exhibit 21.1 List of Subsidiaries of NioCorp Developments Ltd. (the “Company”) Name State/Province of Formation Ownership 0896800 B.C. Ltd. (“0896800”) British Columbia 100% Elk Creek Resources Corp. Delaware 81.33% NioCorp Advanced Metals and Alloys, LLC Delaware 100% NioCorp Technologies Limited United Kingdom 100% (1) Represents 100% of Class A common stock owned by 0896800, and 3,516,140 Vested Shares and 3,391,596 Earnout Shares (each as defined in the Company’s Annual Report on Form 10-K for the year ended June 30, 2026) held by third parties, and outstanding as of June 30, 2026. (1)
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EXHIBIT 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in Registration Statement Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333-270541, and 333-271266 on Form S-1, Nos. 333-280176 and 333-290837 on Form S-3 and Nos. 333- 290671 and 333-222313 on Form S-8 of our report dated September 25, 2026, relating to the financial statements of NioCorp Developments Ltd. appearing in this Annual Report on Form 10-K for the year ended June 30, 2026. /s/ DELOITTE & TOUCHE LLP Denver, Colorado September 25, 2026
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EXHIBIT 23.2 CONSENT OF QUALIFIED PERSON Dahrouge Geological Consulting USA Ltd. hereby consents to the public filing of Sections 1.1 to 1.5, 1.7, 1.12, 1.17, 2, 3, 4, 5, 6, 7, 8, 9, 11, 16, 20, 22.1, 22.7, 23.1, 23.9, 24 and 25 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Dahrouge Geological Consulting USA Ltd. also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333- 271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333- 280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333- 222313) (collectively, the “Registration Statements”). Dahrouge Geological Consulting USA Ltd. also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Dahrouge Geological Consulting USA Ltd. also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Dahrouge Geological Consulting USA Ltd. certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Centennial, Colorado. /s/Trevor Mills Trevor Mills, P.G., SME-RM Principal Geologist / US Operations Manager Dahrouge Geological Consulting USA Ltd.
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EXHIBIT 23.3 CONSENT OF QUALIFIED PERSON SMH Process Innovation hereby consents to the public filing of Sections 1.6, 1.6.2, 1.10, 10, 10.1, 10.3, 14.1, 14.2, 14.2.2, 14.3, 14.3.2, 14.4, 14.4.2, 14.5, 14.5.2, 14.6, 14.6.2, 22.3, 22.4, 23.2 and 23.6 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). SMH Process Innovation also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333- 254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). SMH Process Innovation also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. SMH Process Innovation also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). SMH Process Innovation certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Salt Lake City, Utah. /s/Eric Larochelle Eric Larochelle, B. Eng. Owner SMH Process Innovation
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EXHIBIT 23.4 CONSENT OF QUALIFIED PERSON Dumas Contracting USA Inc. hereby consents to the public filing of Sections 13.4.5, 13.5.2, 13.7, 13.8, 13.9, 15.2.3, 15.2.4 and 15.6.1 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Dumas Contracting USA Inc. also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333- 254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Dumas Contracting USA Inc. also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Dumas Contracting USA Inc. also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Dumas Contracting USA Inc. certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Timmins, Ontario, Canada. /s/Tony Linton Tony Linton, FEC, P.Eng. Director, Engineering & Technical Services Dumas Contracting USA Inc.
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EXHIBIT 23.5 CONSENT OF QUALIFIED PERSON Amplify Mine Planning LLC hereby consents to the public filing of Sections 1.8, 1.9, 12, 13.1, 13.4, 13.4.1, 13.4.2, 13.4.3, 13.4.4, 13.5, 13.5.1, 13.5.3, 13.5.4, 13.6, 13.6.1, 13.6.2, 13.6.3, 13.6.6, 22.2 and 23.4 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Amplify Mine Planning LLC also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333- 254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Amplify Mine Planning LLC also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Amplify Mine Planning LLC also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Amplify Mine Planning LLC certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Centennial, Colorado. /s/Scott Britton Scott Britton, P.E. Principal Consulting Engineer Amplify Mine Planning LLC
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EXHIBIT 23.6 CONSENT OF QUALIFIED PERSON BBA Consultants International LP hereby consents to the public filing of Sections 1.11.1, 15.8, 15.9, 15.10, 15.11, 15.12, and 22.5.1 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). BBA Consultants International LP also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). BBA Consultants International LP also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. BBA Consultants International LP also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). BBA Consultants International LP certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Lakewood, Colorado. /s/Troy Meyer Troy Meyer, P.E. Chief Geotechnical Quality Engineer BBA Consultants International LP
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EXHIBIT 23.7 CONSENT OF QUALIFIED PERSON Olsson hereby consents to the public filing of Sections 1.13, 17, 22.6 and 23.8 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Olsson also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333- 270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Olsson also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Olsson also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Olsson certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Omaha, Nebraska. /s/Brian Osborn Brian Osborn, BSc Environmental Technical Expert Olsson
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EXHIBIT 23.8 CONSENT OF QUALIFIED PERSON Adrian Brown Consultants Inc. hereby consents to the public filing of Section 13.3 (the “Covered Section”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10- K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Adrian Brown Consultants Inc. also consents to the incorporation by reference of the Covered Section in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Adrian Brown Consultants Inc. also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Adrian Brown Consultants Inc. also consents to any extracts from or a summary of the Covered Section in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Adrian Brown Consultants Inc. certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Section. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Denver, Colorado, USA. /s/Adrian Brown Adrian Brown, P.G., PE Principal Engineer Adrian Brown Consultants Inc.
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EXHIBIT 23.9 img79551898_0 CONSENT OF QUALIFIED PERSON Andrieux & Associates Geomechanics Consulting, L.P. hereby consents to the public filing of Sections 13.2, 13.6.5 and 23.3 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Andrieux & Associates Geomechanics Consulting, L.P. also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333- 279429, 333-271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333- 290671 and 333-222313) (collectively, the “Registration Statements”). Andrieux & Associates Geomechanics Consulting, L.P. also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Andrieux & Associates Geomechanics Consulting, L.P. also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Andrieux & Associates Geomechanics Consulting, L.P. certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 in Montreal, Quebec, Canada. /s/Patrick Andrieux Patrick Andrieux, Ph.D., P.Eng., Eng. Principal Engineer Andrieux & Associates Geomechanics Consulting, L.P.
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EXHIBIT 23.10 CONSENT OF QUALIFIED PERSON Tetra Tech hereby consents to the public filing of Sections 1.11, 14.7, 15.1, 15.2, 15.2.1, 15.2.2, 15.3, 15.4, 15.5, 15.6, 15.6.2, 15.7, 22.5 and 23.7 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Tetra Tech also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333- 270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Tetra Tech also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Tetra Tech also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Tetra Tech certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Salt Lake City, Utah. /s/David Winters David Winters, SE, PE Project Manager and Senior Principal Engineer Tetra Tech
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EXHIBIT 23.11 CONSENT OF QUALIFIED PERSON T Engineering hereby consents to the public filing of Sections 13.6.4 and 15.13 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). T Engineering also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333- 270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). T Engineering also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. T Engineering also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). T Engineering certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Oakville, Ontario. /s/Bernie Ting Yen Jui (Bernie) Ting, P. Eng., MASc. Principal, SME and Lead Engineer T Engineering
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EXHIBIT 23.12 CONSENT OF QUALIFIED PERSON Magemi Mining Inc. hereby consents to the public filing of Sections 1.6.1, 10.2, 14.2.1, 14.3.1, 14.4.1, 14.5.1 and 14.6.1 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Magemi Mining Inc. also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333- 254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Magemi Mining Inc. also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Magemi Mining Inc. also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Magemi Mining Inc. certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at North York, Ontario, Canada. /s/Georgi Doundarov Georgi Doundarov, M.SC, P.Eng., PMP, CCP CEO Magemi Mining Inc.
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EXHIBIT 23.13 CONSENT OF QUALIFIED PERSON Metallurgy Concept Solutions hereby consents to the public filing of Sections 1.6.3, 10.4, 14.2.3, 14.3.3, 14.4.3, 14.5.3, 14.6.3 and 23.5 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). Metallurgy Concept Solutions also consents to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). Metallurgy Concept Solutions also consents to the use of and references to our name, including our status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. Metallurgy Concept Solutions also consents to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). Metallurgy Concept Solutions certifies that we have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Valleyfield, QC, Canada. /s/Sylvain Harton Sylvain Harton, P. Eng. President & Owner Metallurgy Concept Solutions
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EXHIBIT 23.14 CONSENT OF QUALIFIED PERSON I, Scott Honan, M.Sc., SME-RM, consent to the public filing of Sections 1.14, 1.15, 1.16, 18, 19, 21 and 22.8 (the “Covered Sections”) of the Technical Report Summary titled “Technical Report Summary, Elk Creek Project, Nebraska” with an Effective Date of June 30, 2026 (the “Technical Report Summary”) as an exhibit to the Annual Report on Form 10-K for the fiscal year ended June 30, 2026 (the “Form 10-K”) of NioCorp Developments Ltd. (the “Company”). I also consent to the incorporation by reference of the Covered Sections in the Company’s Registration Statements on Form S-1 (Registration Nos. 333-285066, 333-279429, 333-271268, 333-254511, 333-270541 and 333-271266), Registration Statements on Form S-3 (Registration Nos. 333-280176 and 333-290837) and Registration Statements on Form S-8 (Registration Nos. 333-290671 and 333-222313) (collectively, the “Registration Statements”). I also consent to the use of and references to my name, including my status as an expert or “qualified person” (as defined in Subpart 1300 of Regulation S-K promulgated by the U.S. Securities and Exchange Commission), in connection with the Form 10-K, the Registration Statements and the Technical Report Summary. I also consent to any extracts from or a summary of the Covered Sections in the Form 10-K and incorporated by reference in the Registration Statements (the “Disclosure”). I certify that I have read the Disclosure being filed by the Company and that it fairly and accurately represents the information in the Covered Sections. ***SIGNATURE PAGE FOLLOWS***
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Signed and dated this 25th day of September, 2026 at Centennial, Colorado, USA. /s/Scott Honan Scott Honan, M.Sc., SME-RM Chief Operating Officer NioCorp Developments Ltd.
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EXHIBIT 31.1 CERTIFICATION I, Mark A. Smith, certify that: 1. I have reviewed this Annual Report on Form 10-K of NioCorp Developments Ltd.; 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report; 4. The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have: (a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared; (b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles; (c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and (d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and 5. The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions): (a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and (b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting. Date: September 25, 2026 By: /s/ Mark A. Smith Mark A. Smith Chief Executive Officer (Principal Executive Officer)
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EXHIBIT 31.2 CERTIFICATION I, Neal Shah, certify that: 1. I have reviewed this Annual Report on Form 10-K of NioCorp Developments Ltd.; 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report; 4. The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have: (a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared; (b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles; (c) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and (d) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and 5. The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions): (a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and (b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting. Date: September 25, 2026 By: /s/ Neal Shah Neal Shah Chief Financial Officer (Principal Financial and Accounting Officer)
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EXHIBIT 32.1 CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350 AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 In connection with the Annual Report on Form 10-K of NioCorp Developments Ltd. (the "Company"), for the year ended June 30, 2026, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Mark A. Smith, Chief Executive Officer of the Company, hereby certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge: 1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. Date: September 25, 2026 By: /s/ Mark A. Smith Mark A. Smith Chief Executive Officer (Principal Executive Officer)
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EXHIBIT 32.2 CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350 AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 In connection with the Annual Report on Form 10-K of NioCorp Developments Ltd. (the "Company"), for the year ended June 30, 2026, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Neal Shah, Chief Financial Officer of the Company, hereby certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge: 1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. Date: September 25, 2026 By: /s/ Neal Shah Neal Shah Chief Financial Officer (Principal Financial and Accounting Officer)
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EXHIBIT 95.1 MINE SAFETY DISCLOSURES The following disclosure is provided pursuant to Section 1503 of the Dodd-Frank Wall Street Reform and Consumer Protection Act (the "Dodd-Frank Act"), Section 13(a) of the Securities Exchange Act of 1934, as amended, and Item 104 of Regulation S-K (17 C.F.R. § 229.104), in respect of each coal or other mine of NioCorp Developments Ltd. (the "Company") or any of its subsidiaries that was subject to the jurisdiction of the U.S. Department of Labor, Mine Safety and Health Administration ("MSHA") under the Federal Mine Safety and Health Act of 1977, as amended (the "Mine Act"), at any time during the three months ended June 30, 2026. The Elk Creek Critical Minerals Project in Johnson County, Nebraska (the "Elk Creek Project"), operated by Elk Creek Resources Corp. ("ECRC"), an indirect majority-owned subsidiary of the Company, is subject to the jurisdiction of MSHA under the Mine Act. The MSHA Mine Identification Number for the Elk Creek Project is 25-01332. No other properties of the Company or its subsidiaries were subject to MSHA jurisdiction during the quarter. Other than as set forth below, no events required to be disclosed under Item 104 of Regulation S-K occurred at the Elk Creek Project, or at any other property of the Company or its subsidiaries, during the three months ended June 30, 2026. Citations, Orders, Assessments and Fatalities Mine or Operating Name / MSHA ID Section 104 S&S Citations (1) Section 104(b) Orders (2) Section 104(d) Citations and Orders (3) Section 110(b)(2) Violations (4) Section 107(a) Orders (5) Total Dollar Value of Proposed MSHA Assessments ($) (6) Mining- Related Fatalities Elk Creek Critical Minerals Project (MSHA ID: 25-01332) 1 0 0 0 0 $151 0 Pattern of Violations Notices and Legal Actions Mine or Operating Name / MSHA ID Pattern of Violations Notice Under Section 104(e) (7) Potential Pattern Notice Under Section 104(e) (7) Legal Actions Pending as of Last Day of Period (8) Legal Actions Initiated During Period (8) Legal Actions Resolved During Period (8) Elk Creek Critical Minerals Project (MSHA ID: 25-01332) No No 0 0 0 Notes to the Foregoing Tables: (1) Citations issued under Section 104 of the Mine Act, 30 U.S.C. § 814, for violations that could significantly and substantially contribute to the cause and effect of a mine safety or health hazard (“S&S” citations). (2) Orders issued under Section 104(b) of the Mine Act for failure to abate a cited violation within the period specified in the citation. (3) Citations and orders issued under Section 104(d) of the Mine Act for unwarrantable failure to comply with mandatory health or safety standards.
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(4) Flagrant violations issued under Section 110(b)(2) of the Mine Act, 30 U.S.C. § 820(b)(2). (5) Orders issued under Section 107(a) of the Mine Act, 30 U.S.C. § 817(a), for the existence of an imminent danger. (6) Proposed assessments received from MSHA during the period under 30 C.F.R. Part 100. Amounts shown reflect proposed assessments received during the period and do not reflect any subsequent settlement, adjustment, or final determination. (7) Written notices received from MSHA under Section 104(e) of the Mine Act, 30 U.S.C. § 814(e), of a pattern of violations, or of the potential to have such a pattern. (8) Legal actions before the Federal Mine Safety and Health Review Commission (the “FMSHRC”), including contests of citations, orders, and proposed penalties; complaints for compensation under Section 111 of the Mine Act; complaints of discharge, discrimination, or interference under Section 105 of the Mine Act; applications for temporary relief under Section 105(b)(2) of the Mine Act; and appeals of judges’ decisions or orders to the FMSHRC.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. SK-1300 Technical Report Summary Elk Creek Project, Nebraska PREPARED FOR: N IO C ORP D EVELOPMENTS L TD . EFFECTIVE DATE: JUNE 30, 2026 SIGNATURE DATE: SEPTEMBER 23, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. i | Page P REPARED AND S IGNED BY : 1. Dahrouge Geological Consulting USA Ltd. 2. SMH Process Innovation. 3. Dumas Contracting USA Inc. 4. Amplify Mine Planning LLC 5. BBA Consultants International LP 6. Olsson 7. Adrian Brown Consultants Inc. 8. Andrieux & Associates Geomechanics Consulting, L.P. 9. Tetra Tech 10. Metallurgy Concept Solutions 11. Magemi Mining Inc. 12. T Engineering 13. Scott Honan, M.Sc., SME-RM, NioCorp Developments Ltd.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. ii | Page Table of Contents 1 Executive Summary 1 1.1 Principal Outcomes 1 1.2 Property Location, Description & Ownership 1 1.3 History 2 1.4 Geological Setting & Mineralization 2 1.5 Exploration and Drilling 3 1.6 Mineral Processing & Metallurgical Testing 3 1.6.1 Mineral Processing 3 1.6.2 Hydrometallurgical Testing (Hydromet) 4 1.6.3 Pyrometallurgical Processing (Pyromet) 4 1.7 Mineral Resource Estimation 5 1.8 Mineral Reserve Estimation 6 1.9 Mining Methods 7 1.10 Recovery Methods 8 1.11 Project Infrastructure 9 1.11.1 Tailings 10 1.12 Markets and Contracts 10 1.13 Environmental Studies, Permitting & Social or Community Impact 11 1.14 Capital Cost Estimate 13 1.15 Operating Cost Estimate 14 1.16 Economic Analysis 14 1.17 Conclusions and Recommendations 16 2 Introduction 18 2.1 Registrant 18 2.2 Terms of Reference and Purpose of the Report 18 2.3 Sources of Information 19 2.4 Effective Date 19 2.5 Details of Inspection 19 2.6 Qualifications of Qualified Persons 20 2.7 Units of Measure 22 3 Property Description & Location 22 3.1 Property Location 22 3.2 Mineral Title and Land Tenure 23 3.2.1 Nature and extent of Issuer’s Interest 25 3.3 Royalties, Agreements and Encumbrances 25 3.4 Environmental Liabilities and Permitting 25 3.5 Other Significant Factors and Risks 26 4 Accessibility, Climate, Local Resources, Infrastructure and Physiography 27 4.1 Accessibility and Transportation to the Property 27 4.2 Climate and Length of Operating Season 28 4.3 Physiography 28 4.4 Infrastructure and Local Resources 28 5 History 29 5.1 Exploration History 29 5.2 Ownership History 30 5.3 Historical Mineral Resource Estimates 30 5.4 Historical Mineral Reserve Estimates 30
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. iii | Page 5.5 Historical Production 31 6 Geological Setting, Mineralization and Deposit 32 6.1 Regional Geology 32 6.2 Property Geology 34 6.2.1 Marine Sedimentary Rocks 36 6.2.2 Elk Creek Carbonatite 37 6.2.3 Structural Geology 38 6.3 Mineralization 39 6.3.1 Niobium and Titanium Mineralization 40 6.3.2 Scandium Mineralization 42 6.3.3 Rare Earth Element Mineralization 42 6.4 Deposit Type 43 7 Exploration and Drilling 46 7.1 Exploration 46 7.2 Drilling 47 7.2.1 Project Drilling Procedures 50 7.2.1.1 Collar and Downhole Surveys 50 7.2.1.2 Geomechanical Core Logging 51 7.2.1.3 Geological Core Logging 51 8 Sample Preparation, Analyses & Security 52 8.1 Sample Preparation & Security 52 8.2 Sample Analysis Procedures 54 8.3 Quality Assurance & Quality Control (“QAQC”) Programs 55 8.3.1 Historical QAQC 55 8.3.1.1 Molycorp, 1973-1986 57 8.3.1.2 NioCorp, 2011-2014 58 8.3.1.3 Historical Re-Sampling Programs, 2010-2021 58 8.3.1.4 Quality Assurance and Quality Control 59 8.3.2 NioCorp 2025 QAQC 60 8.3.2.1 Field Quartz Blanks 60 8.3.2.2 Certified Reference Material 62 8.3.2.2.1 Nb Ostandards and Certified Reference Material 63 8.3.2.2.2 Sc standards and Certified Reference Material 64 8.3.2.2.3 TiO standards and Certified Reference Material 65 8.3.2.2.4 Certified Reference Material and other REE results. 65 8.3.2.3 Duplicates 67 8.3.2.4 Third Party Check Samples 74 8.4 Qualified Person’s Opinion on the Adequacy of Sample Preparation, Security & Procedures 77 9 Data Verification 78 9.1 Data Validation 78 9.1.1 Core Processing Protocols 79 9.1.2 Database Validation 79 9.1.3 NioCorp QAQC 79 9.2 Limitations 79 9.3 Qualified Person’s Opinion 80 10 Mineral Processing and Metallurgical Testing 81 10.1 Historical Test Work 81 10.2 Mineral Processing 81 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. iv | Page 10.3 Hydrometallurgy 82 10.3.1 Mineralogy and Feed Characterization 82 10.3.2 Process Development & Flowsheet 83 10.3.2.1 Metallurgical Recoveries and Performance 83 10.3.2.1.1 Area 100 – Ore Activation 84 10.3.2.1.2 Area 200 - Ammonium Chloride Cycle 84 10.3.2.1.3 Area 300 - Hydrochloric Leach 87 10.3.2.1.4 Area 400 – Sulfuric Acid 90 10.3.2.1.5 Area 500 – Chlorination 92 10.3.2.1.6 Area 600 – Rare Earth Elements Extraction 96 10.3.2.1.7 Area 700 - Rare Earth Separation 98 10.3.2.1.8 Area 800 - Chloride Recovery 104 10.3.3 Significant Factors 107 10.4 Pyrometallurgy 108 11 Mineral Resource Estimate 112 11.1 Introduction 112 11.2 Source Database 112 11.3 Geological Domaining 113 11.4 Density Determination and Assignment 113 11.5 Exploratory Data Analysis 114 11.5.1 Distributed Analysis 114 11.5.2 Top Cut Analysis 119 11.5.3 Declustering 124 11.5.4 Correlation Analysis 125 11.6 Data Preparation 126 11.7 Variography 127 11.8 Block Model Resource Estimation 132 11.8.1 Block Model Configuration 132 11.8.2 Estimation Method 133 11.8.3 Estimation Pass Structure 133 11.9 Model Validation 135 11.10 Mineral Resource Classification 140 11.11 Reasonable Prospects of Eventual Economic Extraction 140 11.12 Cut-Off Grade 141 11.13 Mineral Resource Tabulation 141 11.14 Mineral Resource Sensitivity 142 11.15 Relevant Factors 143 12 Mineral Reserve Estimates 144 12.1 Introduction 144 12.2 Conversion, Assumptions, Parameters & Methods 146 12.2.1 Dilution 146 12.2.2 Recovery 148 12.2.3 COG / NSR Calculation 149 12.2.4 Mine Design 153 12.3 Reserves 153 12.4 Relevant Factors 156 13 Mining Methods 157 13.1 Geology Overview 157 13.2 Rock Engineering 157
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. v | Page 13.2.1 Geomechanical Appraisal 157 13.2.1.1 Available Geomechanical Data 157 13.2.1.2 Data Gaps 158 13.2.1.3 In-Situ Stress Conditions 159 13.2.1.4 Rock Mass Geomechanical Domains 159 13.2.1.5 Intact Rock Properties 160 13.2.1.6 Property-Scale Structures 161 13.2.1.7 Rock Mass Jointing 161 13.2.1.8 Rock Mass Classification 163 13.2.1.9 Anticipated Rock Mass Behaviour 163 13.2.2 Geomechanical Guidelines for Mine Design 165 13.2.2.1 Stope Dimensions and Dilution Estimates 165 13.2.2.2 Dimension of Pillars 166 13.2.2.3 Backfill Strength Requirement 167 13.2.2.4 Seismic Conditions 167 13.2.2.5 Infrastructure Proximity Relative to Ore Body 167 13.2.2.6 Ground Support 168 13.3 Hydrogeology Design Parameters 169 13.3.1 Conceptual Hydrogeology 170 13.3.2 Mine Inflow Control 176 13.3.2.1 Mine Inflow 176 13.3.2.2 Groutability of the Elk Creek Orebody 178 13.3.2.3 Grouting Design 181 13.3.2.4 Grout hole drilling 185 13.3.2.5 Inrush Safety 186 13.4 Mine Design 189 13.4.1 Selection of Mining Method 189 13.4.2 Stope Optimization 191 13.4.3 Stope Design 192 13.4.4 Development Design 194 13.4.5 Mine Access 198 13.4.5.1 Dual Portal Box Cut 198 13.4.5.2 Fresh Air Raise 199 13.5 Production Schedule 200 13.5.1 Productivity 200 13.5.2 Box Cut, Portal and Ramp Development 203 13.5.3 Primary Haulage Ramp & Secondary Access Ramp 205 13.5.4 Development and Production Schedule 205 13.6 Mining Operations 208 13.6.1 Production Schedule 208 13.6.2 Development 209 13.6.3 Truck and LHD Haulage 209 13.6.3.1 Development Phase Haulage 209 13.6.3.2 Transition to Railveyor Haulage 210 13.6.3.3 Production Phase Haulage 210 13.6.4 Backfilling 211 13.6.4.1 Normal Operation 211 13.6.4.1.1 Paste Backfill Quality Control 211 13.6.4.2 Upset Conditions 211
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. vi | Page 13.6.5 Ground Support 212 13.6.6 Grade Control and Reconciliation 212 13.7 Ventilation 212 13.8 Airflow Requirements 213 13.8.1 Ventilation Controls 218 13.8.1.1 Ventilation on Demand (VOD) 218 13.8.1.2 Surface Intake Fans 218 13.8.1.3 Auxiliary Fans 218 13.8.1.4 Monitoring and Control Infrastructure 219 13.8.2 Ventilation Model 219 13.8.2.1 Ventilation Numerical Modelling 219 13.8.3 Ventilation Equipment 221 13.8.3.1 Main Surface Ventilation 221 13.8.3.2 Auxiliary Ventilation 223 13.8.3.3 Development Headings 223 13.8.3.4 Crosscut (Draw Points) and Ore/Waste Pass Ventilation 223 13.8.3.5 Substations, Sumps, and Refuge Station Ventilation 223 13.8.3.6 Railveyor Loadout Ventilation 223 13.8.4 Recommended Ventilation Infrastructure 224 13.8.5 Ventilation Power Consumption 225 13.8.6 Mine Air Heating 226 13.8.6.1 Primary Equipment Heat 226 13.8.6.2 Railveyor Heat Loads 226 13.8.6.3 Sumps, Substations, Shops, and Refuge Stations 226 13.8.7 Thermal Exposure 231 13.9 Mine Infrastructure and Services 231 13.9.1 Material Handling System 231 13.9.2 Mine Dewatering System 233 13.9.3 Compressed Air System 235 13.9.4 Underground Water Supply 236 13.9.5 Underground Fuel Storage and Distribution 236 13.9.6 Workshop, Maintenance Bays, and Warehouse 237 13.9.7 Explosives Storage 238 13.9.8 Refuge Stations 239 13.9.9 Surface Electrical Distribution 240 13.9.10 Underground Electrical Distribution 241 13.9.11 Electrical Buried Services Distribution 242 13.9.12 Development Face Grouting 243 13.9.13 Dust Suppression System 244 13.9.14 Communications Systems 244 13.9.15 Safety and Health 245 13.9.16 Workforce 246 13.9.16.1 Development Phase 246 13.9.16.2 Full Production Phase 246 13.9.16.3 Direct and Indirect Designations 246 13.9.16.4 Engineering Maturity and Risk Statement 247 13.9.17 Equipment 247 13.9.17.1 Equipment Strategy and Fleet Basis 247 13.9.17.2 Underground Haulage and Material Handling 247
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. vii | Page 13.9.17.2.1 Load-Haul-Dump Equipment 248 13.9.17.2.2 Engineering Maturity and Implementation 248 13.9.17.2.3 Equipment Table 248 14 Process and Recovery Methods 251 14.1 Overview 251 14.2 Process Plant Design Criteria 252 14.2.1 Surface Crushing, Ore Storage & Mineral Processing 252 14.2.2 Hydrometallurgical Plant 254 14.2.3 Pyrometallurgical Plant 277 14.3 Flowsheets and Process Description 279 14.3.1 Surface Crushing, Ore Storage & Mineral Processing Plant 279 14.3.2 Hydrometallurgical Plant 281 14.3.3 Pyrometallurgical Plant 299 14.3.3.1 Furnace Feed System 301 14.3.3.2 Furnace Operation 302 14.3.3.3 Design of the Induction Furnace 302 14.3.3.3.1 Tapping Schedule — Design Basis 302 14.4 Mass Balances 303 14.4.1 Surface Crushing, Ore Storage & Mineral Processing Plant 303 14.4.2 Hydrometallurgical Plant 304 14.4.3 Pyrometallurgical Plant 310 14.5 Process Equipment 312 14.5.1 Surface Crushing, Ore Storage & Mineral Processing Plant 312 14.5.2 Hydrometallurgical Plant 313 14.5.3 Pyrometallurgical Plant 340 14.6 Power Requirements 341 14.6.1 Surface Crushing, Ore Storage & Mineral Processing Plant 341 14.6.2 Hydrometallurgical Plant 341 14.6.3 Pyrometallurgical Plant 342 14.7 Plant Layout 342 14.7.1 General 342 14.7.2 Mineral Processing Plant, Surface Crushing and Ore Storage 343 14.7.3 Hydrometallurgical Plant 344 14.7.4 Pyrometallurgical Plant 344 15 Project Infrastructure 349 15.1 General Information Site Layout 349 15.2 Electrical Power 350 15.2.1 Microgrid 350 15.2.2 Electrical Power Distribution - Plant and Facilities 350 15.2.3 Electrical Power Distribution – Underground 350 15.2.4 Emergency Power Generation 350 15.3 Control & Communications 351 15.3.1 Process Control System 351 15.3.2 Site Communications 351 15.3.3 Access and Security System 351 15.4 Natural Gas 351 15.4.1 Natural Gas Pipeline to Site 351 15.4.2 Natural Gas Distribution on Site 351 15.5 Plant Water 351
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. viii | Page 15.5.1 Water Treatment Plant 351 15.5.1.1 Flow Equalization 353 15.5.1.2 Softening Clarification 353 15.5.1.3 Multimedia Filtration 353 15.5.1.4 Reverse Osmosis (RO) System 354 15.5.1.5 Sludge Handling 354 15.5.1.6 Evaporation and Crystallization System 355 15.5.2 Process Water 357 15.5.3 Fire Water 357 15.5.4 Potable Water 358 15.6 Auxiliary Buildings and Facilities 358 15.6.1 Mining Infrastructure 358 15.6.2 Supporting Infrastructure 360 15.7 Roads 362 15.7.1 Main Access Road to Site 362 15.7.2 Secondary Site Access Roads 362 15.7.3 Secondary Site Roads 362 15.8 Carbonatite Rock Stockpile 362 15.9 Surface Water Management for TSF and Temporary Stockpile Areas 364 15.9.1 Stockpile 364 15.9.2 Tailings Storage Facility (“TSF”) 364 15.10 Tailings Surface Logistics 367 15.11 Tailings Storage and Associated Facilities 367 15.11.1 Overview and Capacity 367 15.11.2 Design Basis 368 15.11.3 Embankment Configuration 368 15.11.4 Liner System 369 15.11.5 Instrumentation 369 15.11.6 Conceptual Closure 370 15.12 Salt Management Cells 370 15.12.1 Mine Water Holding Function 370 15.12.2 Wastewater Treatment Solids Disposal 371 15.13 Paste Backfill System and Underground Distribution 372 15.13.1 Paste Backfill Plant 372 15.13.1.1 Basis of Design 372 15.13.1.2 Key Design Parameters 373 15.13.1.3 Process Description 374 15.13.1.4 Paste Backfill Plant Design 376 15.13.1.5 Power Requirements 379 15.13.2 Paste Distribution System 379 15.13.2.1 Throughput 379 15.13.2.2 Hydraulic Modelling 379 15.13.2.3 Paste Distribution System Process Description 380 15.13.3 Paste Backfill Test Work 380 15.13.3.1 Characterization 381 15.13.3.2 Paste Mix Design 381 16 Market Studies 382 16.1 Market Studies 382 16.1.1 Niobium Market Overview 382
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. ix | Page 16.1.2 Titanium Tetrachloride (TiCl ) Market Overview 384 16.1.3 Scandium Trioxide Market Overview 388 16.1.3.1 Scandium Trioxide Market Supply 389 16.1.3.2 Scandium Trioxide Market Demands 390 16.1.3.3 Scandium Trioxide Pricing 394 16.1.4 Rare Earth Market Overview 396 16.1.4.1 Market Demand 398 16.1.4.2 Pricing 400 16.2 Contracts and Status 403 16.2.1 Ferroniobium Offtake Agreement with Thyssen Krupp Metallurgical Products GmbH 403 16.2.2 Definitive Offtake Agreement with Traxys North America LLC 404 16.3 Market Dynamics 406 16.3.1 Scandium 406 16.3.2 Dysprosium and Terbium 410 16.3.3 Economic Model Pricing 411 17 Environmental Studies, Permitting & Plans, Negotiations, or Agreements with Local Individuals or Groups 413 17.1 Environmental Studies 413 17.1.1 Soils 413 17.1.2 Climate/Meteorology/Air Quality 413 17.1.3 Cultural and Archaeological Resources 413 17.1.4 Vegetation 413 17.1.5 Wildlife 414 17.1.6 Threatened, Endangered, and Special Status Species 414 17.1.7 Land Use 415 17.1.8 Hydrogeology (Groundwater) 415 17.1.9 Hydrology (Surface Water) 416 17.1.10 Environmental Geochemistry 416 17.1.11 Known Environmental Issues 419 17.2 Waste Management & Disposal 419 17.2.1 Mine Overburden 419 17.2.2 Tailings/Waste Rock/Process Waste (Onsite) 419 17.2.3 Project Waste Disposal (Offsite) 419 17.2.4 Site Monitoring 420 17.2.5 Water Management 420 17.2.6 Chemical and Reagents Handling 420 17.3 Project Permitting Requirements 421 17.3.1 Nebraska Underground Injection Control 426 17.3.2 DHHS Radioactive Materials Program and Licensing 426 17.3.3 Nebraska Air Quality Permitting 426 17.3.4 Nebraska Dam Permitting 427 17.3.5 Permitting Status 428 17.3.6 Post-Performance and Reclamation Bonding 429 17.4 Community Relations and Social Responsibilities 430 17.4.1 Safety and Health 430 17.5 Reclamation & Closure 430 17.5.1 Surface Disturbance 430 17.5.2 Buildings and Equipment 431 17.5.3 Tailings Disposal Facility 431 4
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. x | Page 17.5.4 Closure Cost Estimate 431 17.6 International Standards & Guidelines 432 18 Capital and Operating Costs 433 18.1 Capital Cost Estimate 433 18.1.1 Basis of Estimate 433 18.1.1.1 Mining, Process, and Infrastructure Capital Cost 433 18.1.1.2 Tailings and Tailings Water Management Capital Costs 433 18.2 Capital Cost Summary 433 18.2.1 Capitalized Pre-production Costs 434 18.2.2 Mining Capital Costs 434 18.2.3 Processing Plant Capital Costs 435 18.2.3.1 Processing Indirects 436 18.2.3.2 Process Commissioning 436 18.2.4 Tailings, Stockpile, Salt Management and Paste Tailings Costs 436 18.2.5 Water Management and Infrastructure 437 18.2.6 Site Preparation and Infrastructure Capital Costs 437 18.2.7 Owner’s Costs 437 18.2.8 Closure and Reclamation 438 18.2.9 Sustaining Capital Costs 439 18.2.10 Contingency 439 18.3 Operating Costs 439 18.3.1 Basis of Estimate (BoE) 439 18.3.1.1 Mining Operating Costs BoE 439 18.3.1.2 Process Plant Operating Costs BoE 440 18.3.1.3 Tailings Management Costs 441 18.3.1.4 General and Administrative (G&A) Costs BoE 441 18.3.1.5 Water Supply Operating Costs BoE 441 18.3.1.6 Closure and Reclamation 441 18.3.2 Operating Cost Summary 442 18.3.2.1 Mining Operating Costs 442 18.3.2.2 Process Plants Operating Costs 443 18.3.2.3 Tailings and Salt Management Operating Costs 446 18.3.2.4 Site G&A Operating Costs 446 18.3.3 Mine Operating Costs 448 19 Economic Analysis 450 19.1 Cautionary Statement 450 19.2 Methodology Used 450 19.3 Financial Model Parameters and Assumptions 451 19.3.1 Physicals 452 19.3.2 Revenue 453 19.3.3 Operating 456 19.3.4 Capital Costs 456 19.4 Cashflow Forecasts & Annual Production Forecasts 457 19.5 Taxes, Royalties & Other Interests 458 19.6 Sensitivity Analysis 459 20 Adjacent Properties 465 21 Other Relevant Data and Information 466 21.1 Project Implementation Plan 466 21.1.1 Project Cost Objectives 466
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xi | Page 21.1.2 Project Schedule Objectives 466 21.1.3 Early Works 467 21.1.4 Project Team 467 21.1.5 Project and Document Control 467 21.1.6 Engineering 468 21.1.7 Supply Chain and Procurement 468 21.1.8 Construction Management 468 21.1.9 Commissioning, Operational Readiness, and Early Operations 469 21.2 Risk Assessment 470 21.2.1 2022 Risk and Current Status 470 22 Interpretations and Conclusions 476 22.1 Geology & Mineral Resource 476 22.2 Mining & Mineral Reserve 477 22.3 Recovery Methods 477 22.4 Processing & Metallurgical Testing 478 22.5 Infrastructure 479 22.5.1 Tailings Storage Facility 480 22.6 Environmental, Permitting & Social or Community Considerations 480 22.7 Market Studies & Contracts 481 22.8 Projected Economic Outcomes 482 23 Recommendations 483 23.1 Geology and Resources 483 23.2 Hydrometallurgical Plant 483 23.3 Geomechnical 484 23.4 Mining & Reserves 484 23.5 Pyrometallurgical Plant 485 23.6 Recovery Methods 485 23.7 Infrastructure 485 23.8 Environmental & Social 486 23.9 Summary of Costs for Recommended Work 487 24 References 488 24.1 Definition of Terms 493 24.2 Abbreviations 495 25 Reliance on Information Provided By the Registrant 499 26 Signature Page 500
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xii | Page List of Figures Figure 3-1: Project Location Map 23 Figure 3-2: Project Tenure Map 24 Figure 3-3: Net Smelter Return (“NSR”) Map 25 Figure 4-1: Project Access 27 Figure 6-1: Regional Geology 33 Figure 6-2: Merged Aeromagnetic Anomaly Map of Nebraska, Kansas and Oklahoma showing Midcontinental Rift and Nemaha Uplift 34 Figure 6-3 Generalized Stratigraphy of the Elk Creek Area 35 Figure 6-4: (Left) Drill core illustrating the transition from eroded paleosurface of the Elk Creek Carbonatite Complex to the “Limestone Breccia”. (Right) Photographs of microstructures in the drill core. 36 Figure 6-5: Plan view of the location of the mineralized carbonatite (outlined in red) with underground development projected to surface 40 Figure 6-6: Plan and Cross -Sections of Geologic Model Hanging Wall Boundary and Mineralized Domain 40 Figure 6-7: Basic Statistics of Nb OMineralization 41 Figure 6-8: Correlation Statistics of Nb O and TiO and Fe O 42 Figure 6-9: Basic Statistics of Sc Mineralization 42 Figure 6-10: Schematic Diagram of St. Honoré Carbonatite 45 Figure 7-1: Geology of the Elk Creek Carbonatite as expressed in drill holes at an elevation of 394 ft (120 m) AMSL (approximately 755 ft or 230 m BGS) 46 Figure 7-2: All drilling completed within the area of the Elk Creek Carbonatite Complex 48 Figure 7-3: 2025 Drillhole locations on the Project 49 Figure 8-1: Sample Process Flow Chart (2014 - 2025 drill programs) 53 Figure 8-2: NioCorp Technicians cutting core at the project site. 53 Figure 8-3: Secure storage of the NioCorp Drill holes and pulps. 54 Figure 8-4: Summary of Blank Control Charts for Nb O, Sc, TiO Submission SGS for the 2025 Drill Program 62 Figure 8-5: Summary of Blank Control Charts for Nd, Pr, Dy and Tb Submissions to SGS 62 Figure 8-6: OREAS465 and OREAS464 Results for Nb O 64 Figure 8-7: OREAS465 and OREAS464 Results for Sc 64 Figure 8-8: OREAS465 and OREAS464 Results for TiO 65 Figure 8-9: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Pulp Duplicate) Core Duplicate Analysis for Analytes Nb O and Sc 67 Figure 8-10: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Pulp Duplicate) Core Duplicate Analysis for Analytes TiO, Nd, Pr, Dy and Tb 68 Figure 8-11: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nb O, Sc and TiO 69 Figure 8-12: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nd and Pr. 70 Figure 8-13: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Dy and Tb. 71 Figure 8-14: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nb O, Sc and TiO 72 2 5 2 5 2 2 3 2 5 2 2 5 2 2 5 2 2 5 2 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xiii | Page Figure 8-15: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nd and Pr 73 Figure 8-16: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Dy and Tb 74 Figure 8-17: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Nb O, Sc and TiO 75 Figure 8-18: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Nd and Pr 76 Figure 8-19: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Dy and Tb. 77 Figure 10-1: Calcium (top) and Magnesium (bottom) concentration over time and moving average trendline. 86 Figure 10-2: Ammonium chloride leach performance for Ca and Mg. 87 Figure 10-3: Ca and Mg leaching performance per countercurrent leach stage. 87 Figure 10-4: (a) Ca and Mg distribution in the precipitate from the Ca Precipitation (CaP) and the Magnesium Precipitation (MgP). (b) The aqueous concentration in grams per liter of Ca and Mg after the precipitation process. 87 Figure 10-5: Leach efficiencies for leach 1 and leach 2 in the counter current leach process. 90 Figure 10-6: Ti and Nb water leaching efficiency of acid baked material over various tests. 91 Figure 10-7: Aqueous concentration in gram per liter throughout the hydrolysis procedure for Ti and Nb. (a) NCPn-16, (b) NCPn-17, (c) NCPn-18. 92 Figure 10-8: L3 2026 93 Figure 10-9: Phase II Chlorination Equipment Design 95 Figure 10-10: Concentration of elements over time in the Extraction stage of the solvent extraction system. 99 Figure 10-11: Concentration of elements over time in the Scrub stage of the solvent extraction system. 99 Figure 10-12: Concentration of elements over time in the Strip 1 stage of the solvent extraction system. 100 Figure 10-13: Concentration of elements over time in the Strip 2 and Strip 3 stages of the solvent extraction system. 101 Figure 10-14: Distribution of the LREEs throughout the circuit. 102 Figure 10-15: Distribution of the SEG REEs throughout the circuit. 103 Figure 10-16: Distribution of the Tb, Dy, and Y throughout the circuit. 104 Figure 10-17: Distribution of the HREEs throughout the circuit. 104 Figure 10-18: Demonstration Ferric Chloride Pyro-Hydrolysis Reactor Unit Photo 105 Figure 10-19: Demonstration Ferric Chloride Pyro-Hydrolysis Reactor Unit Schematic 106 Figure 10-20: Iron Oxide Residue 107 Figure 10-21: Pyrohydrolysis residue elemental distribution. 107 Figure 10-22: Chemical analysis results for the 400 g sample supplied by L3 Process Development 110 Figure 11-1: Nb OGrade distribution by domain 115 Figure 11-2: TiO Grade distribution by domain 116 Figure 11-3: Sc Grade distribution by domain 117 Figure 11-4: TREO Grade distribution by domain 118 Figure 11-5: Nb OLog Probability Plot 121 Figure 11-6: TiO Log Probability Plot 121 2 5 2 2 5 2 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xiv | Page Figure 11-7: Sc Log Probability Plot 122 Figure 11-8: TREO Log Probability Plot 123 Figure 11-9: Nb O Ortho Directional Variogram for MCarb Domain. 128 Figure 11-10: Sc Omni Directional Variogram for MCarb Domain 129 Figure 11-11: TiO Omni Directional Variogram for MCarb Domain 130 Figure 11-12: TREO Omni Directional Variogram for MCarb Domain. 131 Figure 11-13: Swath Plot Nb Ofor the MCarb Domain 137 Figure 11-14: Swath Plot Sc for the MCarb Domain 137 Figure 11-15: Swath Plot TiOfor the MCarb Domain 138 Figure 11-16: Swath Plot TREO for the MCarb Domain 139 Figure 12-1: 2026 Elk Creek Study Mine Design 145 Figure 12-2: Sources of Mining Dilution for Typical Stope Layout (Not to scale). 147 Figure 12-3: NioCorp Grade (Nb O)-Tonne Curves Based on NSR Cut-Off 150 Figure 12-4: NioCorp Grade/Tonne Curves Based on NSR Cut-Off (TiO) 151 Figure 12-5: NioCorp Grade (Sc ppm) – Grade Tonne Curves Based on NSR Cut-Off 151 Figure 12-6: NioCorp Grade (TREO %) – Grade Tonne Curves Based on NSR Cut-Off 152 Figure 12-7: Current Mine Design 153 Figure 13-1: Lower hemisphere equal angle plots showing the structural data and joint sets interpretation per structural domain 163 Figure 13-2: Regional Hydrogeology 172 Figure 13-3: Hydrogeology of the Elk Creek Mine – view looking northeast 173 Figure 13-4: Hydraulic Conductivity of Geologic Materials at the Elk Creek Mine 175 Figure 13-5: Mine inflow with no controls — Schematic 177 Figure 13-6: Mine inflow with grout control — Schematic 178 Figure 13-7: Geophysical tests showing widely spaced high permeability flow zones (left panel) and corresponding widely-spaced large aperture voids (right panel) 180 Figure 13-8: Grout hole location plan, showing grouting boreholes, development drifts, mining stopes and sections. 182 Figure 13-9: Section A-A' looking northeast, showing geology, grouting boreholes, development drifts, and mining stopes 183 Figure 13-10: Section B-B looking northwest, showing geology, grouting boreholes, development drifts, and mining stopes 184 Figure 13-11: Example of a mobile concrete batch plant (Photo courtesy of Techwill Inc.) 186 Figure 13-12: Stability of grouted stope outer pillar against water drive — Force diagram 187 Figure 13-13: Vertical stress in 65.6 foot- (20 meter) thick and 131.2 foot- (40 meter) high grouted stope outer pillar located 3,280 feet (1,000 meters) below ground surface with 10 MPa (1,450 psi) water drive applied to outer edge of terminal pillar (blue arrows). All stresses reported in MPa, mesh blocks are 3.28-foot (1-meter) cubes. 188 Figure 13-14: 2026 Current Design 190 Figure 13-15: Undiluted Stope Optimization Results for Varying NSR Cut-Offs 192 Figure 13-16: Stopes and Crosscut Accesses (Cross Section View) 193 Figure 13-17: Level Layout with Stopes and Footwall Accesses (Rotated View Looking North) 194 Figure 13-18: Completed Mine Design (Plan View) 195 Figure 13-19: Completed Mine Design (Cross Sectional View) 195 Figure 13-20: Completed Mine Design - Main Infrastructure (Looking South) 196 Figure 13-21: Mine Design Coloured by Nb OGrade. 196 Figure 13-22: Mine Design Coloured by NSR ($/t) 197 Figure 13-23: Box Cut Design Dimensions – Plan View Looking Northeast 203 Figure 13-24: GSI Proposal for Slope Stability 204 2 5 2 2 5 2 2 5 2 2 5
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xv | Page Figure 13-25: Initial Ramp Development – Isometric View Looking North 205 Figure 13-26: Mine Production Schedule - Colored by Year 208 Figure 13-27: Current Overall Mine Ventilation Layout 213 Figure 13-28: Stage 1 Development to 210 Level 220 Figure 13-29: Life-of-Mine (LoM) Stage 221 Figure 13-30: Main Fan Configuration 222 Figure 13-31: Railveyor System Schematic 233 Figure 14-1: Overall Crushing Conceptual Block Flow Diagram 281 Figure 14-2: Area 100 – Ore Activation Block Flow Diagram 281 Figure 14-3: Area 200 – Ammonium Chloride Cycle Block Flow Diagram 282 Figure 14-4: Area 300 – Hydrochloric Acid Leach Block Flow Diagram 284 Figure 14-5: Area 400 – Sulfuric Acid Block Flow Diagram 286 Figure 14-6: Area 500 – Chlorination Block Flow Diagram 288 Figure 14-7: Area 600 - REE Recovery Block Flow Diagram 292 Figure 14-8: Area 700 – Rare Earth Separation Block Flow Diagram 294 Figure 14-9: Area 800 – Chloride Recovery Block Flow Diagram 298 Figure 14-10: Area 900 – Sulfate Effluent Block Flow Diagram 299 Figure 14-11: Pyrometallurgical Processing Simplified Flowsheet 301 Figure 14-12: Product Summary Block Flow Diagram 304 Figure 14-13: Summary of the pyrometallurgical plant 312 Figure 14-14: Process Plant Layout 343 Figure 14-15: Hydromet Plant 344 Figure 14-16: Pyromet Building Southeast View 345 Figure 14-17: Bulk Feed and Storage 345 Figure 14-18: FeNb Furnace Feed System 346 Figure 14-19: FeNb Furnace, Pelletization Basin, Dryer and Packaging Equipment 346 Figure 14-20: Office and Control Room 347 Figure 14-21: Pyromet Building Northwest View 348 Figure 14-22: Dust Collection and Cooling Systems 348 Figure 15-1: Elk Creek Project Site Plan Layout 349 Figure 15-2: Process Water Treatment Plant Block Flow Diagram 356 Figure 15-3: Overall Water Balance 357 Figure 15-4: Building 31 A – General Mine Admin, First Aid, Dry, and Underground Central Control 359 Figure 15-5: Building 31C - Shop and Battery Charging 360 Figure 15-6: Carbonatite Stockpile Layout 363 Figure 15-7: TSF West Cells Water Management 366 Figure 15-8: TSF East Cells Water Management 366 Figure 15-9: TSF General Arrangement 368 Figure 15-10: Process Flow Diagram of Paste Backfill Plant - Page 1 375 Figure 15-11: Process Flow Diagram of Paste Backfill Plant - Page 2 376 Figure 15-12: Plan View of the Paste Backfill Plant and SSF 377 Figure 15-13: Elevation View of the Paste Backfill Plant and SS 378 Figure 15-14: Paths of the Paste Distribution System Modelled 380 Figure 16-1: Ferroniobium Demand 2025-2035 (kt Nb) 384 Figure 16-2: Ferroniobium Price Forecast 2025-2035 (US$/kg) 384 Figure 16-3: Chinese Indicative TiCl Pricing 386 Figure 16-4: Historical and Forecast TiCl Pricing 388 Figure 16-5: Sc Otonnes Supply and Demand; Established Demand Segments Only 393 4 4 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xvi | Page Figure 16-6: Projected Sc OPrice per Kg through 2035 395 Figure 16-7: Lanthanide Series for REE's modified after Van Gosen 2014. 397 Figure 16-8: Historical global consumption and forecasted demand for NdFeB magnets by end-use category 399 Figure 16-9: Forecasted China domestic price of dysprosium oxide 401 Figure 16-10: Forecasted China domestic price of terbium oxide 402 Figure 16-11: Forecasted China price of neodymium oxide, praseodymium oxide and didymium oxide. 402 Figure 18-1: Reagent Consumption Percentages for the Hydrometallurgical facility 445 Figure 18-2: Natural Gas Consumption per Process area in Hydrometallurgy 446 Figure 19-1: Pre-Tax NPV Sensitivity Analysis 460 Figure 19-2: Pre-Tax IRR Sensitivity Analysis 460 Figure 19-3: After-Tax NPV Sensitivity Analysis 460 Figure 19-4: After-Tax IRR Sensitivity Analysis 461 Figure 19-5: Pre-Tax NPV Sensitivity to Grade and Recovery 461 Figure 19-6: After Tax NPV Sensitivity to Grade and Recovery 462 Figure 19-7: Pre-Tax IRR Sensitivity to Grade and Recovery 462 Figure 19-8: After Tax IRR Sensitivity to Grade and Recovery 463 Figure 19-9: Before-Tax NPV Profile 463 Figure 19-10: After-Tax NPV Profile 464 Figure 20-1: Adjacent Properties 465 Figure 21-1: Likelihood and Consequence Matrix 470 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xvii | Page List of Tables Table 1-1: Elk Creek Mineral Resource Estimate by Classification Inclusive of Reserves 5 Table 1-2: Elk Creek Mineral Resource Estimate by Classification Exclusive of Reserves 5 Table 1-3 Elk Creek Mineral Reserves 6 Table 1-4: Capital Costs Summary (US$ 000’s) 13 Table 1-5: Operating Cost Summary 14 Table 1-6: Indicative Economic Results 15 Table 2-1: A summary of the site visit inspections by the QP consultants 19 Table 2-2: List of Qualified Persons responsible for sections of this Report 21 Table 3-1: Active Option to Purchase Agreements Covering the Project 24 Table 5-1: Historical Exploration Summary 30 Table 6-1: Project rock types as defined by Molycorp and DGC 37 Table 6-2: List of Elements & Oxides Associated with REE Mineralization 43 Table 7-1: Drilling Completed within the Carbonatite Complex 47 Table 7-2: 2025 Drill Hole Summary 49 Table 8-1: Analytical methods used for sample assay. 54 Table 8-2: Summary of Historical Sample Preparation, Analysis, and QA/QC Programs — Elk Creek Project 56 Table 8-3: Summary of Field Quartz Blank Performance — 2011 and 2014 Drill Programs (Nb₂O₅) 59 Table 8-4: Summary of designed level of insertion of QC submissions in the 2025 drill program. 60 Table 8-5: Summary of 2025 Drill Program Field Blank Insertion 61 Table 8-6: Summary of the CRM used for the 2025 Program 62 Table 8-7: Summary of the Nb OResults per CRM (SGS) 63 Table 8-8: Summary of the Sc Results per CRM (SGS) 64 Table 8-9: Summary of the TiOResults per CRM (SGS) 65 Table 8-10: REE performance on CRM's OREAS 465, ORES463, GRE-11 and GRE-08 66 Table 9-1: Summary of QP Site Visits 78 Table 10-1: Summary of Historical Technical Reports 81 Table 10-2: Ore Feed Characterization Summary 83 Table 10-3: Product Recoveries per area 83 Table 10-4: Ammonium chloride test conditions and associated recoveries for select tests. 84 Table 10-5: HCl-PLS composition of for high and low density scenarios. 88 Table 10-6: Test conditions and leach efficiencies for select HCl leaching tests. 89 Table 10-7: Experiment test conditions and results for select acid bake-water leach tests. 90 Table 10-8: Experiment test conditions and results for select hydrolysis tests. 91 Table 10-9: Phase I Experimental Conditions 93 Table 10-10: Phase I Results 93 Table 10-11: Phase II Experimental Conditions 95 Table 10-12: Phase II Results 96 Table 10-13: Extraction PLS Description 96 Table 10-14: Experiment test conditions and results for select DGA-6 extraction tests 96 Table 10-15: Experiment test conditions and results for select DGA-6 scrub tests 97 Table 10-16: REE solvent extraction operational parameters. 98 Table 11-1: Bulk density by estimation domain 114 Table 11-2: Top Cut Summary by Domain and Analyte 124 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xviii | Page Table 11-3: Optimum cell size ranges used for cell declustering by domain and analyte. 125 Table 11-4: Pearson Correlation Matrix (Capped Composite Grades by Domain) 126 Table 11-5: Variogram Model Parameters: All Domains and Analytes 127 Table 11-6: Block Model Configuration Parameters 132 Table 11-7: Bulk Density Summary by Geologic Domain 133 Table 11-8: Multi-Pass Estimation Parameters 134 Table 11-9: Mineral Resource Classification Material 140 Table 11-10: NSR Conversion, Recoveries and Pricing 141 Table 11-11: Elk Creek Mineral Resource Estimate Inclusive of Reserve - Effective June 30, 2026 141 Table 11-12: Elk Creek Mineral Resource Estimate Exclusive of Reserve – Effective June 30, 2026 142 Table 11-13: Elk Creek Mineral Resource Sensitivity 142 Table 12-1: Mineral reserves as of June 30, 2026 and stated in this report 144 Table 12-2: Potential sources of mining dilution by stope type (primary and secondary) for a typical stope geometry and standard mining practices in the ground conditions expected at Elk Creek. 148 Table 12-3: Example of an NSR Block Calculation 149 Table 12-4: Operating Costs Used for Mine Design NSR Cut-off 152 Table 12-5: In-situ Underground Mineral Reserves Estimate for Elk Creek, Effective Date June 30, 2026 154 Table 13-1: Summary of available geomechanical data from drill holes for the Elk Creek Project 157 Table 13-2: In-situ stress conditions considered for the Elk Creek Project 159 Table 13-3: Number of valid intact rock strength laboratory tests per geomechanical domain used to establish intact rock strength envelopes. 160 Table 13-4: Summary of intact rock mechanical properties per geomechanical domain. 160 Table 13-5: Summary of mean joint set orientations per structural domain 162 Table 13-6: Summary of rock mass classification per geomechanical domain 163 Table 13-7: Undiluted Stope Optimization Results for Varying NSR Cut-offs 192 Table 13-8: Mine Design Summary - by Activity Type 197 Table 13-9: Productivity Rates 200 Table 13-10: Dimensions by Heading Types 201 Table 13-11: Workforce Schedule Parameters for Underground 202 Table 13-12: Cut Design Dimensions 203 Table 13-13: Mine Production Schedule 206 Table 13-14: Airflow Determination 215 Table 13-15: Ventilation Infrastructure Matrix 224 Table 13-16: Equipment Heat 228 Table 13-17: Underground Equipment 249 Table 14-1: Process Design Criteria 252 Table 14-2: Plant Design Criteria 255 Table 14-3: Area 100 – Ore Activation Process Design Criteria 255 Table 14-4: Area 200 – Ammonium Chloride Cycle Process Design Criteria 255 Table 14-5: Area 300 – Hydrochloric Acid Leach Process Design Criteria 257 Table 14-6: Area 400 – Sulfuric Acid Process Design Criteria 258 Table 14-7: Area 500 – Chlorination Process Design Criteria 260 Table 14-8: Area 600 – Solvent Extraction Process Design Criteria 264 Table 14-9: Area 700 – Rare Earth Separation 266 Table 14-10: Area 800 – Chloride Recovery Process Design Criteria 275
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xix | Page Table 14-11: Area 900 – Sulfate Effluent Treatment Process Design Criteria 276 Table 14-12: Pyrometallurgical process design criteria. 277 Table 14-13: Comminution Circuit Material Balance 303 Table 14-14: Recovery of Saleable Products 304 Table 14-15: Area 100 / 200 Summary Mass Balance Table 306 Table 14-16: Area 300 / 400 Summary Mass Balance Table 307 Table 14-17: Area 500 Summary Mass Balance Table 308 Table 14-18: Area 600 / 700 Summary Mass Balance Table 308 Table 14-19: Area 700 Summary Mass Balance Table 309 Table 14-20: Area 800 Summary Mass Balance Table 309 Table 14-21: Reagent and approximate feed rate (t/d). 311 Table 14-22: FeNb Furnace Partition Coefficients 311 Table 14-23: Primary Equipment List 312 Table 14-24: Ancillary Equipment List 313 Table 14-25: Area 100 – Ore Activation Summary Equipment List 314 Table 14-26: Area 200 – Ammonium Chloride Cycle Summary Equipment List 315 Table 14-27: Area 300 - Hydrochloric Acid Leach Summary Equipment List 319 Table 14-28: Area 400 – Sulfuric Acid Summary Equipment List 321 Table 14-29: Area 500 – Chlorination Summary Equipment List 324 Table 14-30: Area 600 – Solvent Extraction Summary Equipment List 328 Table 14-31: Area 700 – Rare Earth Separation Summary Equipment List 330 Table 14-32: Area 800 – Chloride Recovery Summary Equipment List 338 Table 14-33: Area 900 – Sulfate Effluent Summary Equipment List 340 Table 14-34: Pyrometallurgical processing major equipment list. 341 Table 14-35: Installed power breakdown 342 Table 14-36: FeNb Furnace Power Requirements 342 Table 15-1: Design Requirements 352 Table 15-2: TSF Infrastructure Description 364 Table 15-3: TSF Capacity Summary 367 Table 15-4: Expected Quality of Formation Water to WWT 370 Table 15-5: Primary Expected Solid Flows to Salt Cell from Process Water Treatment 371 Table 15-6: Paste Backfill System Key Design Parameters 373 Table 15-7: Backfill Throughput Rates 379 Table 16-1: Niobium Producers 383 Table 16-2: North American TiCl₄ Producers (2024) 385 Table 16-3: TiCl Demand by End-Use Application (Excl. TiO Pigment) 386 Table 16-4: Indicative TiCl Production Cost Breakdown (TZMI Model) 388 Table 16-5: Known Scandium Oxide Producers, Feedstock and Status 389 Table 16-6: Scandium Oxide Supply vs. Demand by Year 393 Table 16-7: Price Forecast by Region 2025 through 2035 395 Table 16-8: Comparison of NioCorp Pricing to publicly available information. 402 Table 16-9: Price projections, current US$, scandium oxide per Kg by source, 2025-35. 408 Table 16-10: Revised Price projections, current US$, scandium oxide per Kg by source, 2025-36 409 Table 16-11: Argus Non-Ferrous Market Pricing for Dy and Tb 410 Table 16-12: Pricing Comparison – Resource/Reserve versus Economic Model 412 Table 17-1: Project Permits 421 Table 18-1: Capital Costs Summary (US$ 000’s) 434 Table 18-2: Mine Direct Initial Capital Cost Breakdown 435 4 2 4
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. xx | Page Table 18-3: Mine Indirect Capital Cost Breakdown 435 Table 18-4: Process Plant Costs Summary 435 Table 18-5: Processing Indirects Cost Summary 436 Table 18-6: Pre-production Facilities 436 Table 18-7: Owner’s Costs 437 Table 18-8: LOM Operating Cost Unit Rate Summary 442 Table 18-9: Steady State Mining Operating Unit Cost 443 Table 18-10: ROM Processing Operating Cost Unit Rate Breakdown 444 Table 18-11: Support Roles for Facility Operations 447 Table 18-12: Steady State Mining Operating Unit Cost 448 Table 19-1: General Assumptions 451 Table 19-2: Mining Physicals 452 Table 19-3: Processing Physicals 453 Table 19-4: Pricing Assumptions 453 Table 19-5: Scandium Trioxide Pricing Assumptions 454 Table 19-6: TREO Pricing Assumptions 454 Table 19-7: Operating Cost Summary 456 Table 19-8: Capital Cost Summary (US$ 000’s) 456 Table 19-9: Initial Capital Costs Summary (US$ 000’s) 457 Table 19-10: Indicative Economic Results (US$ 000’s) 457 Table 22-1: Hydromet Elemental Recovery Summary 478 Table 24-1: Summary of general mining terms potentially used in this Technical Report Summary. 493 Table 25-1: Information supplied by Registrant 499
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 1 | Page 1 E XECUTIVE S UMMARY NioCorp Developments Ltd. (“NioCorp” or the “Company”) is a U.S.-based mineral development company focused on developing several critical minerals from the proposed Elk Creek, Nebraska Critical Minerals Mine (the “Elk Creek Mine,” the “Elk Creek Project” or the “Project”). NioCorp plans to produce eight commercial mineral products — ferroniobium, scandium oxide, titanium tetrachloride, NdPr oxide, Tb oxide, Dy oxide, SEG carbonate and heavies carbonate from a single underground orebody. All of the Elk Creek Project’s products have been designated as “Critical Minerals” by the U.S. Government, as have the rare earth elements. NioCorp is a publicly traded company that is listed on the NASDAQ under the ticker symbol “NB”. This Technical Report Summary ( this “Technical Report Summary,” “TRS” or “Report”) for the Elk Creek Project (“the Project”) located in southeast Nebraska was prepared for NioCorp in accordance with Item 601(b)(96) and subpart 1300 of Regulation S-K (“Regulation S-K 1300”) promulgated by the United States Securities and Exchange Commission (“SEC”) by Dahrouge Geological Consulting USA Ltd. (“DGC”), SMH Process Innovation (“SMH”), Amplify Mine Planning LLC (“Amplify”), Adrian Brown Consultants, Inc. (“ABC”), BBA Consultants International LP, formerly Tierra Group International, Ltd. (“Tierra Group/BBA”), Olsson, Andrieux & Associates Geomechanics Consulting, L.P. (“A2GC”), Magemi Mining Inc. (“Magemi”), Dumas Contracting USA Inc. (“Dumas”), T Engineering (“T Eng”), Tetra Tech, Metallurgy Concept Solutions (“MCS”), and Scott Honan, M.Sc., SME-RM, NioCorp (collectively, the “Qualified Persons” or “QPs”). This Technical Report Summary summarizes the results of a pre-feasibility study (as that term is defined under Regulation S- K 1300) (the “2026 Elk Creek Study”) prepared by the Qualified Persons. The reason that the 2026 Elk Creek Study does not qualify as feasibility study under Regulation S-K 1300 is because additional work with respect to the engineering of and procurement for the planned surface plant is required to allow the Qualified Person to reduce the overall contingency range attributed to the initial capital expenditure estimate for the Elk Creek Project from the current 14% to less than or equal to 10%. 1.1 P RINCIPAL O UTCOMES This Technical Report Summary is based on processing of 45,929,462 tons of ore over a 40-year operational life to produce 205,464 tons of Nb in the form of ferroniobium, 4,585 tons of scandium oxide, 2,341,367 tons of TiCl4, 25,923 tons of NdPr oxide, 690 tons of Tb oxide, 2,649 tons of Dy oxide, 13,886 tons of SEG carbonate and 10,161 tons of heavies carbonate. This has been estimated using a cut-off of US$218/ton. The initial capital cost is US$ 1,849 million. The total capital cost is US$ 4,019 million including sustaining and closure/reclamation capital. The overall contingency on initial capital is 14%. Based on current assumptions and design listed in this report, the project returns a pre-tax NPV 8% of US$ 4,111 million and an IRR of 24.0% along with an after-tax NPV 8% of US$ 3,441 million and IRR of 22.8%. 1.2 P ROPERTY L OCATION , D ESCRIPTION & O WNERSHIP The Project is located in southeast Nebraska, USA. It is located approximately 47 miles southeast of Lincoln, Nebraska (the state capital), and 68 miles south of Omaha, Nebraska. The Property is located
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 2 | Page within the U.S. Geological Survey Tecumseh Quadrangle Nebraska SE (7.5-minute series) mapsheet in Sections 1-6, 9-11; Township 3N; Range 11 and Sections 19-23, 25-36; Township 4N, Range 11. The area is well developed with direct access to roads, rail, supply and distribution companies, and a local workforce including heavy equipment operators. The Project consists of one 709.93-acre parcel of land 100% owned by the Company along with six option-to purchase agreements covering approximately 1,010.96 acres. Option agreements are between NioCorp's wholly owned subsidiary Elk Creek Resources Corp. (“ECRC”) and the individual landowners. The parcel owned by the Company contains most of the Mineral Resources and Mineral Reserves associated with the project. NioCorp retains 100% of the mineral rights to the Property and is the operator. The option agreements are in the form of pre-paid Exploration Lease Agreements (ELA), with an Option to Purchase (OTP) the mineral rights and/or the surface rights at any time during the term of the agreement. The individual landowners have title to the surface and subsurface rights, and the agreements are primarily concerned with only the mineral and surface interest of each property. The agreements convey to the Company adequate surface rights to access the land and to complete mineral exploration work. The option agreements that the Company currently holds include all the Mineral Resources and Mineral Reserves described in this report. Except for a 2% NSR royalty attached to the parcel owned by NioCorp and the OTPs that include the mineral rights, the Property has no other outstanding royalties, agreements, or encumbrances. 1.3 H ISTORY Exploration activities on the Property prior to NioCorp ownership were conducted by the University of Nebraska – Lincoln, Nebraska Conservation and Survey Division, United States Geological Survey (“USGS”), Cominco American Inc. (“Cominco American”), Molybdenum Corporation of America and later Molycorp Inc. (“Molycorp”). These activities consisted of airborne magnetic and gravity surveys, geochemical sampling and core drilling. Since 2011, NioCorp has completed extensive project development work on its Elk Creek Project, including Reverse Circulation (RC) drilling, core drilling, metallurgical testing, multiple Mineral Resource Estimates and Mineral Resource updates, two Preliminary Economic Assessments completed in 2015, and feasibility studies completed in, 2017, 2019 and 2022. 1.4 G EOLOGICAL S ETTING & M INERALIZATION The Project includes the Elk Creek Carbonatite (“the Carbonatite”) that intruded older Precambrian granitic and low to medium grade metamorphic basement rocks. Both the Carbonatite and Precambrian rocks are interpreted to be unconformably overlain by approximately 650 ft of Paleozoic marine sedimentary rocks of Pennsylvanian age. As a result of this thick cover, there is no surface outcrop within the Property area of the Carbonatite, which was identified and targeted through magnetic surveys and confirmed through subsequent drilling. The available magnetic data indicates dominant northeast, west-northwest striking lineaments, and secondary northwest and north-oriented features that mimic the position of regional faults parallel and/or perpendicular to the Nemaha Uplift. The Carbonatite hosts significant niobium (reported as Nb2O5), titanium (reported as TiO2) and scandium (reported as Sc) and is composed predominantly of dolomite, calcite and ankerite, with lesser chlorite, barite, phlogopite, pyrochlore, serpentine, fluorite, sulphides and quartz. Niobium is
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 3 | Page contained primarily within the mineral pyrochlore, and rare earth element (REE) mineralization is reported to occur as bastnäsite, parisite, synchysite and monazite. The Elk Creek Deposit (“the Deposit”), as defined in the Mineral Resource Estimate, consists of niobium, titanium, scandium and rare earth mineralization that is chiefly hosted within a magnetite (hematite) dolomite carbonatite. 1.5 E XPLORATION AND D RILLING Multiple drilling programs have been completed on the Project. The first were conducted by Molycorp during the 1970s and 1980s, followed by a second program by Quantum Rare Earth Development Corp. (predecessor to NioCorp) in 2011 and another three programs by NioCorp in 2014, 2015 and 2025. The 2014 program included nineteen holes drilled for resource estimation, totalling 52,389 ft. The 2015 program included five holes, totaling 11,000 ft drilled for hydrogeological and geotechnical studies and were not used for resource estimation. To date, a total of 160 drillholes have been completed within the Carbonatite complex totalling 269,905 ft (82,267 m), with 79 drillholes completed on the Property totalling 178,602 ft (54,438 m). The 2025 drilling program was specifically designed to target gaps within the current Mineral Resource in support of converting a portion of the Resource from Indicated and Inferred to Measured, Indicated and Inferred. The drilling for the 2025 program was completed by Boart Longyear Company – Western Coring, 7013 West Augusta Ave, Glendale, Arizona 85303. Drilling was initiated on April 29, 2025, and was completed on October 3, 2025. During this campaign a total of 16 HQ diameter drillholes were completed totalling 37,861 ft (11,540 m) utilizing 2 (two) LF-160 drill rigs, one track mounted and one truck mounted core drill. All drilling was completed using diamond coring methods (Table 7‐2). Overburden was cased using HWT casing, and the remainder of the drillholes were completed using HQ thereafter. 1.6 M INERAL P ROCESSING & M ETALLURGICAL T ESTING 1.6.1 Mineral Processing The comminution test work was completed in two stages at SGS Canada Inc. (“SGS”) in Lakefield, Ontario in 2016. The primary stage test work (SGS Canada Inc., 2016a) was conducted on six composite samples and 13 variability samples and included: • Bond Rod Mill Work Index (Rwi) testing. • Bond Ball Mill Work Index (Bwi) testing. • Bond Abrasion Index (Ai) testing. • Bond Low-energy Impact (Cwi) testing. • JK Drop Weight (JKDW) testing. • Semi-autogenous grinding (SAG) Mill Comminution (SMC) testing. The second stage of comminution test work (SGS Canada Inc., 2016b) was conducted on a single composite sample, using a LABWAL high-pressure grinding roll (HPGR) semi-pilot scale test work program.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 4 | Page The test work results indicate that the Project ore is categorized as soft to moderately hard in terms of ore hardness, and amenable to standard grinding as well as an HPGR operation. A bulk representative sample (approximately 3,000 kg) of ore was subjected to locked cycle pilot scale testing at NRRI- Coleraine in Minnesota. The ore tested indicates that it is amenable to processing via the HPGR. Autogenous layer buildup and flake generation were both acceptable, and there was, on average, 40% < 1 mm product generated from the HPGR when in steady state. The most notable observations from the testing are: (1) Final product particle size is largely independent of press force and moisture. (2) Specific energy increases as both moisture and press force increase. (3) There is a decrease in specific throughput as the press force increases. (4) There is a decrease in specific throughput as the feed moisture increases. Based on the results as indicated above, it would be recommended to run an installed HPGR at lower pressures, i.e. 3.0 N/mm2 or less, and to remove as much free water from the circuit as possible. This will have the effect of reducing power requirements with limited to no impacts on size reduction. The data as collected to date is suitable for full HPGR scale up and process guarantees around envisioned plant operation conditions. 1.6.2 Hydrometallurgical Testing (Hydromet) Metallurgical test work was conducted at L3 Process Development between 2021 and 2026, with post-FS optimization test work on-going. The test work campaigns were used to develop and optimize the flowsheet and process units to extract and purify a crude niobium oxide product suitable for further treatment into ferroniobium (FeNb) as well as marketable products of titanium chloride, scandium trioxide, dydimium oxide (Nd(Pr) oxide), terbium oxide and dysprosium oxide from Elk Creek Ore. Test work consisted of multiple bench and pilot scale hydrometallurgical test programs followed by the operation of an integrated demonstration scale circuit aimed at further refining the final flowsheet using different reagents and technologies. The operation of the demonstration plant showed that high recovery rates of the niobium, scandium, rare earths and titanium could be achieved, and that recycling and regeneration of reagents was also possible; thus, minimizing fresh reagent input and waste generation. Recoveries of 84.7% Nb, 80.5% Ti, 94.3% Sc, 88.7-94.4% NdPr, 94.4% Tb, and 94.6% Dy have been demonstrated. 1.6.3 Pyrometallurgical Processing (Pyromet) The initial KPM test work completed in 2016 established the basis for the Pyromet process, with niobium recovery estimated at 96%. Building on this work, XPS testing conducted in September 2025 successfully demonstrated the production of ferroniobium alloy from the sodium-bearing Hydromet feed. Further evaluation completed in April 2026 confirmed the technical viability of the process and established that titanium must be removed from the Hydromet feed. The remaining development priorities include achieving consistent Hydromet feed composition, improving slag fluidity and metal–slag separation, selecting an appropriate refractory, implementing effective phosphorus control, and conducting additional representative-scale testing to confirm the achievable niobium recovery.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 5 | Page 1.7 M INERAL R ESOURCE E STIMATION The Mineral Resource Estimate for the Elk Creek Carbonatite Project has been prepared by Dahrouge Geological Consulting USA Ltd. (DGC) and has an effective date of June 30, 2026. The estimate is reported in accordance with Regulation S-K 1300. The resource is estimated within three geological domains (MCARB, DOL_CARB, and LAMP) utilizing hard boundaries and modeled in Leapfrog GeoTM. All domains are defined from lithological logging of 65 diamond core drill holes of HQ size. Grade estimation is completed in Maptek VulcanTM using Ordinary Kriging informed by a domain specific variogram model, applied to a database of 39,098 composites. Top cutting is applied selectively by domain and analyte to manage high grade outliers, and cell declustering is applied throughout to correct for clustered drill spacing. The resulting block model is validated through global mean comparison, swath plot analysis, and grade tonnage curve comparison, and is considered unbiased and geologically reasonable. Mineral Resources are reported in-situ and effective as of June 30, 2026. Mineral resources are classified as Measured, Indicated or Inferred based on estimation pass number and slope of regression, and are reported at a cut-off of NSR > US$218/ton, reflecting updated operating cost assumptions from the 2026 Elk Creek Study (Table 1‐1). Table 1‐1: Elk Creek Mineral Resource Estimate by Classification Inclusive of Reserves Classification Cut-off NSR (US$/ton) Tonnage (Mtons)Nb₂O₅ (%) TiO₂ (%) Sc (ppm) TREO (%) Measured 218 21.7 0.61 2.46 69.1 0.35 Indicated 218 187.4 0.5 2.36 59.85 0.36 Measured + Indicated 218 209.1 0.51 2.38 60.81 0.36 Inferred 218 169.2 0.38 2.14 51.02 0.39 Table 1‐2: Elk Creek Mineral Resource Estimate by Classification Exclusive of Reserves Classification Cut-off NSR (US$/ton) Tonnage (Mtons)Nb₂O₅ (%) TiO₂ (%) Sc (ppm) TREO (%) Measured 218 14.1 0.53 2.05 47.6 0.39 Indicated 218 149.0 0.43 1.70 42.5 0.39 Measured + Indicated 218 163.1 0.44 1.89 45.3 0.39 Inferred 218 169.2 0.38 2.14 51.02 0.39 Source: Dahrouge 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 6 | Page (1) Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resource will be converted to Mineral Reserves. (2) Mineral Reserves are reported separately in Section 12 of this report. (3) Prepared in accordance with Regulation S-K 1300 (4) NSR cut-off of US$218/ton (US$240/tonne) based on longhole stoping underground mining; incorporates metallurgical recoveries of Nb 86.72%, TiO₂ 83.65%, Sc 92.00%, and REE by-products 92.00%, at metal prices of US$52.00/kg Nb, US$2,000.00/kg Sc, US$1.86/kg TCl4, US$1,845.00/kg Tb₂O₃, US$125.00/kg NdPr, and US$8.97/kg SEG carbonate. (5) TREO = LREO + HREO expressed as a percentage (TREO% = TREO ppm ÷ 10,000) (6) Tonnages in millions of short tons (Mtons). Grades rounded to reflect the approximate nature of resource estimates. (7) Totals may not sum due to rounding. This estimate supersedes the 2022 Mineral Resource Estimate and reflects the introduction of a Measured category, revised Inferred tonnage in the DOL_CARB domain, and an increased NSR cut-off. Full detail on the estimation methodology, parameters, and classification criteria is provided in Section 11 of this report. 1.8 M INERAL R ESERVE E STIMATION The Project has advanced from late-stage exploration into initial development, with underground long hole stoping identified as the preferred mining method based on the Deposit geometry and available geotechnical information. The mine plan incorporates paste backfill to improve recovery, enable adjacent stope extraction, and reduce the need for rib pillars. Mineral Reserves were defined by applying appropriate modifying factors to Measured and Indicated Mineral Resources in accordance with Regulation S-K 1300. As of June 30, 2026, the Elk Creek underground Mineral Reserve Estimate totals 45.93 million tons, comprising 7.57 million tons Proven and 38.36 million tons Probable reserves at an NSR cut-off of US$218/ton. The total reserve grades average 0.759% Nb₂O₅, 2.68% TiO₂, 69.3 ppm Sc, and 0.34% TREO. The reserve supports a 43-year life of mine (3 years development, 40 years operating), with a design strategy targeting an average cut-off grade of 0.650% Nb₂O5 and a life-of- mine average NSR of US$590.84/ton. Mineral Reserves are represented as in-situ, as of June 30, 2026. Table 1‐3 Elk Creek Mineral Reserves 2026 Reserve Mineral Reserve Classification Cut-off NSR Tonnage Grade Grade Grade Grade (US$/ton) (ton) (NbO%) (TiO%) (Sc ppm) (TREO %) Proven 218 7,570,098 0.760 2.70 71.5 0.32 Probable 218 38,359,365 0.759 2.67 68.8 0.35 Total 218 45,929,462 0.759 2.68 69.3 0.34 Classification Tonnage (ton) NbO Grade (%) FeNb (ton) Payable Nb (ton) TiO G rade (%) Payable TiCl (ton) Sc Grade (ppm) Payable ScO (ton) TREO Grade (ppm) Payable TREO (ton) Proven 7,570,098 0.76 53,651 34,873 2.70 405,938 71.5 762 3,232 22,509 Probable 38,359,365 0.76 271,386 176,401 2.67 2,036,334 68.8 3,717 3,489 123,115 2 5 2 2 5 2 4 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 7 | Page Total 45,929,462 0.76 325,038 211,274 2.68 2,442,272 69.3 4,479 3,446 145,625 Source: Amplify Mine Planning LLC, 2026. Notes: (1) All figures are rounded to reflect the accuracy of the estimates. Totals may not sum due to rounding. (2) The Qualified Person for the Mineral Reserve estimate is Amplify Mine Planning LLC. The estimate has an effective date of June 30, 2026. (3) The Mineral Reserve is based on the mine design and mine plan, utilizing an average cut-off grade of 0.650% Nb2O5 with an NSR of US$ 218/ton. (4) The estimate of Mineral Reserves may be materially affected by metal prices, environmental, permitting, legal, title, taxation, socio-political, marketing, infrastructure development, or other relevant issues. The underground mine design uses primary and secondary stoping within three mining horizons separated by partially recoverable sill pillars. Standard stope dimensions are planned at approximately 49 ft wide, with variable stope lengths of 33 ft to 49 ft and 131 ft level spacing. Primary and secondary stopes are expected to achieve 95% recovery, while sill pillar stopes are assigned 62.5% recovery. Mining dilution averages approximately 6%, derived from 3% dilution for primary stopes, 9% for secondary stopes, and 5% for ore development. Access to the deposit will be provided by two spiral ramps driven from a surface box cut: a primary access ramp for personnel, equipment, services, intake ventilation, and logistics; and a secondary haulage ramp serving as exhaust ventilation, a secondary escapeway, and the route for a Railveyor® ore haulage system. The haulage ramp has been extended deeper than prior feasibility study designs to reflect the increased Mineral Reserve base and to improve access to higher-grade ore zones. The Railveyor® system is sized to support the planned daily mine and mill production requirements. Ore will be mined using underground LHDs, trucks, ore passes, conveyors, and the Railveyor® system for transport to surface stockpiles. Mine access, underground infrastructure, surface infrastructure, ventilation, tailings, and material handling systems have been designed to align with production requirements and the selected mining method. Based on the information presented, no known environmental, permitting, legal, socio-economic, marketing, political, or other factors are currently identified that would materially affect the underground Mineral Reserve Estimate. 1.9 M INING M ETHODS Geomechanical investigations included core logging, televiewer surveys, laboratory rock strength testing, and numerical modelling. Geomechanical analyses supported the selected mining method, stope dimensions, dilution assumptions, ground support requirements, and backfill strength criteria. The selected mining method for the deposit is underground longhole stoping with cemented paste backfill, chosen to balance economic viability, geotechnical suitability, orebody geometry, and the need for selective extraction of higher-grade Nb₂O₅ mineralization. While bulk mining methods such as block or sub-level caving may be technically and economically feasible, they were not preferred due to limited grade selectivity under the 3,047 tpd milling constraint. The mine plan is organized into three resource blocks mined generally together using a declining-grade strategy, with bottom-up sequencing, primary/secondary stoping, and partial sill pillar recovery. Stope designs use 49 ft widths, 33–49 ft panel lengths, and 131 ft level spacing, with dilution of approximately 6% and 95% ore recovery applied. The resulting design supports approximately 45.93 million ore tons at 0.759% Nb₂O₅, producing an estimated 316,099 tons of ferroniobium over a mine life of about 43 years,
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 8 | Page including 40 years at full production. The schedule targets steady-state production of 3,047 tpd and approximately 8,282 t/y ferroniobium, with production beginning 16 months after ramp development starts and ramping up over the following six months. 1.10 R ECOVERY M ETHODS The recovery process is an integrated multi-stage hydrometallurgical flowsheet designed to extract and separate the following products: niobium, titanium, scandium, and four magnetic rare earth elements (Pr, Nd, Tb and Dy) from the Elk Creek Ore. All major unit operations are commercially demonstrated technologies. The overall circuit has been engineered to achieve commercially relevant specification for all products while minimizing tailings. The principal commercial products are niobium oxide intended for conversion into ferroniobium, titanium tetrachloride (TiCl₄), high-purity oxides of didymium (NdPr), terbium, dysprosium and scandium. Mixed SEG (Sm, Eu, Gd) and HREY (Ho, Er, Tm, Yb, Lu, Y) carbonate concentrates are produced as secondary products. Process sequence: • Area 100 – Ore Activation: Indirect-fired calcination converts carbonate minerals to oxides and recovers CO₂ for reuse. • Area 200 – Ammonium Chloride Cycle: Two-stage counter-current ammonium chloride leaching selectively removes calcium and magnesium from the ore. Both are mineralized as carbonates, fully regenerating the ammonium chloride solution; a portion of the carbonates is used in the process for neutralization purposes while the excess reports to paste backfill. • Area 300 – Hydrochloric Acid Leach: Two-stage counter-current HCl leaching dissolves the rare earth elements (including scandium) and associated impurities, generating a pregnant leach solution for solvent extraction and a niobium-titanium residue. • Area 400 – Sulfuric Acid Treatment: Acid baking, water leaching, hydrolysis and calcination convert the niobium-titanium residue into a chlorination feed. • Area 500 – Chlorination: Fluid-bed chlorination followed by staged condensation and purification produces commercial-grade TiCl₄. Niobium and iron are recovered as a mixed chloride that is hydrolyzed and calcined to an oxide intermediate feed to pyrometallurgy for ferroniobium production. • Area 600 – Rare Earth Element Recovery: Diglycolamide solvent extraction recovers scandium and the rare earths from the HCl pregnant leach solution. • Area 700 – Rare Earth Separation: A multi-circuit solvent extraction unit using Cyanex 801 and Cyanex 572 extractants separates the mixed rare-earth solution into high-purity didymium, terbium, dysprosium and scandium oxides, together with the two mixed carbonate by-products. • Area 800 – Chloride Recovery: Pyro-hydrolysis of the chloride waste streams regenerates hydrochloric acid and recovers metal oxides for disposal into paste backfill. • Area 900 – Sulfate Effluent Management: Neutralization and dewatering of sulfate streams produce solids suitable for paste backfill, with treated water returned to the process.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 9 | Page The flowsheet is deliberately sequenced to first remove acid-consuming calcium and magnesium, then extract the rare earths and scandium together with the majority of the base metals, followed by treatment of the refractory niobium-titanium minerals, and finally recovery and recycle of the principal reagents (ammonium chloride, hydrochloric acid, and carbon dioxide). This design supports efficient production of multiple critical minerals while minimizing consumable requirements and environmental discharges. 1.11 P ROJECT I NFRASTRUCTURE There are several local communities near the Project, including Elk Creek, Tecumseh, Pawnee City and Syracuse that are intended to provide local housing for the Project construction and operating staff. There are several other communities within driving distance, and the large cities of Lincoln and Omaha are within reasonable driving distance. Both cities have substantial regional airports. Presently, the site has no existing infrastructure except for access via the Nebraska State Highway 50 and County Road 721. The Project will be accessed from the North from County Road 721 through a guarded gate house into the Project property. A secondary access point is available on the east side of the project from Highway 50. The Project will incorporate surface and underground infrastructure, as well as surface tailings and salt storage facilities. The offsite infrastructure includes a water supply pipeline from the City of Tecumseh along with temporary and permanent natural gas pipelines. On-site power will be provided by a third party microgrid based off modular 2.5 MW natural gas fired generators, rated at approximately 50 MW. A small amount of grid power (200 kW) will also be used. Telecommunications service will be provided by the local telecom supplier with on-site telecommunications distribution consisting of a combination of hardwire and fiber optics systems. The on-site surface infrastructure will include: • the microgrid generation system, including switchgear, transformer and a power distribution system; • on-site telecommunications; • fuel storage and dispensing system for above ground vehicles; • temporary fuel storage and dispensing system for the underground mine during mine construction; • truck scale; • process water treatment center; • potable water/fire water system including tankage, distribution and hydrants; • sanitary wastewater collection system with lift stations pumping to an on-site sewage lagoon • natural gas distribution to site loads; and • access roads to the site with parking, fencing and security.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 10 | Page Infrastructure building facilities will have an administration building and security gate house, assay laboratory, combination warehouse and maintenance shop, modular warehouse/maintenance shop offices, process water treatment plant building, and the mine change building. The mining related facilities will include a lined mine waste rock and ore storage area, surface water control facilities, and the tailings and salt impoundments. The mine surface facilities include the mine portal, surface Railveyor installation and Railveyor maintenance facility, mine control room, mine substations, paste backfill plant, the mine ventilation system and the mine dry. The underground facilities will include shop / warehouse areas, offices, explosives storage areas, electrical distribution system, water pumping and discharge system, process water distribution, ventilation infrastructure, compressed air distribution, and the backfill distribution system. The underground material handling system includes three loadout facilities equipped with grizzlies to load the Railveyor system, which will transport ore and waste to surface. A modular grout plant will be constructed near injection well NEC15-003 at the approximate geographic center of the resource. The grout plant will provide grout for the underground grouting program in the first year of construction, as well as shotcrete for underground use. The modular grout plant will then be relocated adjacent to the mine portal and will continue to supply shotcrete for mine use. 1.11.1 Tailings The tailings storage facilities (“TSFs”) are designed for storage of paste tailings solids in lined facilities permitted under State of Nebraska Industrial Solid Waste regulations. Based on the parameters and assumptions outlined in Section 18.11, the TSFs have been designed with adequate containment and capacity to manage the planned production of waste streams over the life of the mine. 1.12 M ARKETS AND C ONTRACTS Market studies for niobium, titanium dioxide and scandium trioxide are an important part of the proposed Elk Creek Mine. These products, especially niobium and scandium trioxide (scandium), are thinly traded without an established publicly available price discovery mechanism. Marketing studies and product price assumptions are based on research, and forecasts and NioCorp management’s knowledge of the markets for the following products: • Niobium: CMP Group Market Report, 2025 • Scandium: OnG Market Reports, 2025 and 2026 • Titanium: TZMI Market Report and Pricing Estimate, 2025 • Magnetic Rare Earths: Adamas Intelligence Q2/25 outlook, base case • SEG and Heavy Rare Earths: Adamas forecast 2025, base case NioCorp is considering selling ferroniobium, scandium trioxide and titanium dioxide products from the Project through all avenues, which include entering into long-term offtake contracts and Letters of Intent with buyers. Niobium, titanium, scandium and rare earth elements (“REEs”) comprise the mineral reserve reported in this Technical Report Summary, as well as the mineral resource. The rare earth elements (lanthanides plus yttrium), comprise a wide variety of markets, some more thinly traded and opaque
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 11 | Page than others. However, the "magnetic” rare earths (neodymium, praseodymium, terbium, and dysprosium) which are used to manufacture rare earth permanent magnets are more widely traded and are the primary REEs of interest for the Project. The Company has utilized market studies and forecasts from Adamas Intelligence (Adamas Intelligence, 2019 and 2022) to support inclusion of the REEs into the mineral resource. At the time of this report, NioCorp had entered into two off-take agreements covering 75% of the ferroniobium and an MOU for the balance of production. It is assumed that product not covered by an offtake agreement will be sold on a spot price, ex-mine gate basis. 1.13 E NVIRONMENTAL S TUDIES , P ERMITTING & S OCIAL OR C OMMUNITY I MPACT NioCorp has developed information and conducted the following environmental studies for baseline site characterization: • Soils • Climate/meteorology/air quality • Cultural and archeological resources • Vegetation • Wildlife • Threatened, endangered, and special status species • Land use • Hydrogeology (groundwater) • Hydrology (surface water) • Wetlands/riparian zones • Geochemistry (Section 17.1.10) There are low levels of naturally occurring radioactive materials (NORMs) in this ore body. Therefore, waste materials (e.g., RO treatment salts and process waste/tailings), water sourced from the carbonatite and wastewater have the potential for low radioactivity levels. Gross alpha, gross beta, and radioactivity of nine isotopes analyzed in process tailings indicated that fugitive dust and external radiation exposure are potential concerns for this setting. Three parameters (gross alpha, Ra-226, and Ra-228) exceeded the screening level but were below respective MCLs. Results indicate that the site materials are non- hazardous and will be permitted/managed as non-hazardous. Confirmation testing will be performed as the mine processes are developing and as permitting processes proceed. These waste materials will be landfilled in the on-site solid waste disposal units and closed according to those permits. Dewatering will be required during excavation of the mine portal. A construction dewatering permit has been secured from the Nebraska Department of Water, Energy, and Environment (DWEE) and NioCorp will maintain compliance with conditions of this permit. Dewatered groundwater from the portal excavation will be directed to a stormwater detention pond which will gradually discharge to an intermittent tributary to Elk Creek. Demonstration process plant residuals (water leach residue, Fe-oxide, and Mg/Ca Carbonate) were analyzed with a comprehensive suite of static tests. Tailings were also characterized using the Toxicity Characteristic Leaching Procedure (“TCLP”), including the eight inorganic substances
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 12 | Page expected to be present in the material (organic parameters are not expected to be present in the material). This set of results has no parameters exceeding regulatory action levels. Details can be found in Section 17.1.10. Detailed geochemical results from the demonstration process plant indicated, in sum, that while some waste material contained acidic characteristics, treatment and disposal facilities planned for the site would be sufficiently protective of the environment. Acid-base accounting results indicate that water leach would not have persistent acid-containing potential. Excavated portal material/uncontaminated overburden consists of marine sediments and will be crushed and used as construction fill/material. The permitted solid waste disposal units will receive waste from the surface production plant and from the mining operation. These waste sources include waste rock, tailings, process wastes, and slag. Waste rock sourced from the carbonatite will be placed in a lined impoundment on the surface or co-disposed with the tailings in lined impoundments. Plant waste streams will be combined with water, cement, and fly ash and either pumped underground as structural fill in the underground mine or pumped to engineered and lined surface disposal impoundments. Pyrometallurgical slag will be hauled to the same engineered and lined surface disposal impoundments. Once the mine is in operation, it is expected up to 200 gpm of mine groundwater will be pumped and treated through an RO treatment system. This clean water will be used in the process plant, and the RO reject will be evaporated and crystallized and disposed of in the onsite Salt Management Cell. Stakeholder engagement has been previously completed for the Project, including town halls (Most recently in December 2025) and individual meetings with pertinent stakeholders. NioCorp met with Johnson, Pawnee, Nemaha, and Richardson County representatives as well as representatives from the Southeast Nebraska Development District (Batty et al. 2022). No additional stakeholder engagement has been identified for the Project at this stage, as the community at large remains supportive of the Project. The mineral exploration process is permitted through Nebraska’s Mineral Exploration Permit. Nebraska does not have a specific permit for operating mines but has a comprehensive permitting process that applies to any industrial undertaking. This permitting process includes mining plans, mining reclamation and bonding/financial assurance. While the formal operational permitting program for the Project is dependent upon the completion of the mine plan, preliminary permitting and consultation as necessary to initiate portal excavation and construction has been completed. These permits and authorizations have allowed for the commencement of mine portal excavation and construction, and other construction and operations permits as needed have been scheduled for initiation as needed to support the remaining stages of construction and commencement of operation. The Project has or will provide these items including financial surety for proper closure and reclamation of the site; the estimated direct cost for closure and reclamation, is US$106 million using a 2026 cost basis. Engagement of local and state regulators is currently in progress. At this time, NioCorp has completed the following: (1) Nebraska Department of Water, Energy, and Environment (DWEE) Mineral Exploration Permit for exploration drilling;
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 13 | Page (2) DWEE air quality construction permit; (3) DWEE authorization for Class V underground injection well for the hydrogeological portion of the exploration drilling; (4) Johnson County road use and maintenance agreement; (5) Johnson County special use permit; (6) DWEE construction stormwater permit; (7) DWEE construction dewatering discharge permit; (8) notification of Commencement of Operations with the Mine Safety and Health Administration (MHSA); and (9) Johnson County floodplain development permit. At this time, there are no known environmental concerns that would materially impact NioCorp’s ability to extract the mineral reserves at the Elk Creek Project. Environmental permitting timelines at the state level require up to six months for processing of most individual permits, with roughly 18 months needed for solid waste permitting for tailings impoundments. Broadly speaking, general permits can be active within seven to 10 days of providing a full and complete application package. 1.14 C APITAL C OST E STIMATE Table 1‐4 shows the breakout in initial and sustaining capital estimates. An overall 14% contingency factor has been applied to the initial capital estimate. The pre-production period is defined as the first 35 months, after which the mine and plant are operating at nameplate capacity. Table 1‐4: Capital Costs Summary (US$ 000’s) Description Initial Sustaining Total Capitalized Preproduction Expenses $2,506 $2,506 Site Preparation and Infrastructure $24,722 $42,032 $66,754 Processing Plant $870,468 $309,322 $1,179,790 Water Management & Treatment $13,000 $13,000 Mining Infrastructure $144,938 $382,347 $527,285 Tailings Management $56,874 $168,930 $225,804 Site Wide Indirects $3,894 $3,894 Processing Indirects $33,620 $33,620 Mining Indirects $169,167 $999,917 $1,169,084 Owner's Costs Indirects $296,437 $2,522 $298,959 Closure and Reclamation $0 $95,930 $95,930 Contingency $233,409 $169,168 $402,577
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 14 | Page Description Initial Sustaining Total Total Capital Costs $1,849,036 $2,170,168 $4,019,204 Source: NioCorp 2026 1.15 O PERATING C OST E STIMATE Operating cost estimates were developed to show monthly and annual costs for production. All unit costs are expressed as US$/ton processed and are based on Q2 2026 US$. Operating cost metrics in the technical economic model are developed on a unit rate basis and applied to the 40-year operating period of the project, from the end of construction to the end of the mine life. The total operating cost unit rate of US$ 268.78/st processed is summarized in Table 1‐5. Table 1‐5: Operating Cost Summary Description LOM $/st ore Hydromet 128.01 Mining 71.34 Pyromet 17.69 Water Management 14.44 Site G&A 13.26 Infrastructure 8.60 Paste Plant 7.34 Mineral Processing 7.12 Product Packaging 0.97 Total 268.78 Source: NioCorp 2026 1.16 E CONOMIC A NALYSIS The results of the economic analysis represent forward-looking information that is subject to a number of known and unknown risks, uncertainties and other factors that may cause actual results to differ materially from those presented here. Forward-looking statements in this Report include, but are not limited to, statements with respect to future niobium, scandium, titanium and rare earth prices, the estimation of Mineral Resources and Mineral Reserves, the estimated mine production and niobium, scandium, titanium, and rare earths recovered, the estimated capital and operating costs, and the estimated cash flows generated from the planned mine production. Actual results may be affected by: • Differences in estimated initial capital costs and development time from what has been assumed in this Technical Report Summary.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 15 | Page • Unexpected variations in the quantity of ore, grade or recovery rates, or presence of deleterious elements that would affect the process plant or waste disposal. • Unexpected geotechnical and hydrogeological conditions from what was assumed in the mine designs, including water management during construction, mine operations, and post mine closure. • Differences in the timing and amount of estimated production, costs of future production, sustaining capital requirements, future operating costs, assumed currency exchange rate, requirements for additional capital, and unexpected failure of plant, equipment or processes not operating as anticipated. • Changes in government regulation of mining operations, environment, and taxes. • Unexpected social risks, higher closure costs and unanticipated closure requirements, and mineral title disputes. The production schedules and financial analysis annualized cash flow tables are presented with conceptual years shown. Years shown in these tables are for illustrative purposes only. If additional mining, technical, and engineering studies are conducted, these may alter the Project assumptions as discussed in this Report and may result in changes to the calendar timelines presented and the information and statements contained in this Report. The technical economic model metrics are prepared on an annual pre-tax and after-tax basis, the results of which are summarized in Table 1‐6. Based on current assumptions and design listed in this Report, the project returns a pre-tax NPV 8% of US$ 4,111 million and an IRR of 24.0% along with an after-tax NPV 8% of US$ 3,441 million and IRR of 22.8%. Table 1‐6: Indicative Economic Results Pre-Tax NPV ($M) $4,111 Pre-Tax IRR 24.0% After-Tax NPV ($M) $3,441 After-Tax IRR 22.8% After-Tax Payback Period (years) 2.93 Total Upfront CAPEX ($M) $1,849 Mine Life (years) 40 LoM Gross Revenue ($M) $37,435 Niobium ($M) $9,781 Scandium ($M) $14,331 Titanium ($M) $3,946 Rare Earths ($M) $9,378 NdPr Oxide ($M) $3,255 Dy Oxide ($M) $3,137 Tb Oxide ($M) $2,827 SEG Carbonate ($M) $113 Heavy Rare Earth Carbonate ($M) $46 Average Annual EBITDA ($M) $608 8% 8%
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 16 | Page Average EBITDA Margin over LoM (EBITDA as % of total revenue) 67% Average Annual Operating Cash Flow over LoM ($M) $519 Revenue Per Ton, (US$/ton) $815 Annual Operating Cost (OPEX) (US$/ton) ($255) Effective Tax Rate 14.3% Development Timeline (months) 35 Source: NioCorp 2026 1.17 C ONCLUSIONS AND R ECOMMENDATIONS Based on the data available and the analyses described in this Technical Report Summary, the Project has a valid Mineral Resource and Mineral Reserve. The Elk Creek deposit is a carbonatite-hosted, multi-element system defined by drilling and geophysics across three estimation domains (MCARB, DOL_CARB, LAMP); the Mineral Resource Estimate, effective June 30, 2026 and prepared in accordance with Regulation S-K 1300 which totals 209.1 Mt Measured + Indicated and 169.2 Mt Inferred at a US$218/ton NSR cut-off, and is considered unbiased and geologically reasonable based on domain-specific variography, Ordinary Kriging, and validation against the declustered composite mean. DGC is not aware of any drilling, sampling, or QA/QC factors that would materially affect the reliability of the resource database. Key uncertainties are geological confidence at depth and along the peripheral DOL_CARB domain margins, the relatively large Inferred tonnage compared to Measured and Indicated, and the sensitivity of the NSR cut-off to metallurgical recovery and commodity prices across seven analytes, particularly niobium and scandium. Long-hole open stoping, with a primary/secondary paste-backfill sequence, is confirmed as the appropriate mining method based on geotechnical characterization, and the mine design, production schedule (3,047 tons/d steady state), and grouting-based hydrogeological control plan are considered technically sound. Metallurgical testing indicates the ore is amenable to standard grinding or HPGR comminution, and demonstration-plant operation of the hydrometallurgical circuit has achieved high recoveries of niobium, scandium, rare earths, and titanium (84.7% Nb, 80.5% Ti, 94.3% Sc, 88.7-94.4% NdPr, 94.4% Tb, 94.6% Dy), supported by a flowsheet update that reduced acid consumption, reagent use, and process complexity while adding rare earth products. The Pyromet program has established the technical feasibility of producing ferroniobium alloy from Hydromet feed via aluminothermic reduction; SMH, MCS, and Magemi Mining are confident the design will yield the expected product suite, though further development work is required to confirm slag behavior, feed consistency, and refractory selection at commercial scale. Project infrastructure, including power, water, and site facilities, is expected to meet the Project's needs based on current design assumptions, and six tailings storage facilities have been designed with adequate capacity for the mine plan. It is recommended that hydrometallurgical optimization continue, focused on the ammonium chloride and chloride pyrohydrolysis circuits and on larger-scale piloting of the chlorination and rare earth separation units to reduce capital cost and finalize process calibration; that a larger-scale Pyromet test program be conducted using representative Hydromet feed to confirm design parameters, refractory compatibility, and phosphorus control at commercial scale; and that a comprehensive paste backfill testing and heat- integration (Pinch Analysis) program be undertaken to address the identified impact of carbonate content on backfill strength and to optimize energy recovery in the Hydromet flowsheet. 1
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 17 | Page No known environmental factors are expected to materially affect the Project's ability to extract its mineral reserves, and NioCorp has obtained the permits needed to commence mine portal excavation and construction, with a current closure and reclamation cost estimate of US$106 million; risks remain in the permitting process given the limited precedent for this type of mining in Nebraska. Market studies support the marketability of the Project's product suite notwithstanding thinly traded pricing, with offtake and marketing agreements in place for a substantial portion of planned production. Total life-of-mine capital costs are estimated at US$4,019 million (including initial capital of US$1,849 million over a 35-month construction period), and total operating costs are estimated at US$268.78 per ton processed; on this basis, the Project is expected to generate a pre-tax NPV (8% discount) of US$4,111 million and an IRR of 24.0%, and a post-tax NPV of US$3,441 million and an IRR of 22.8%, over a 40-year mine life. Olsson recommends continued, transparent engagement with identified stakeholders and with state and local regulators throughout construction and operation, to maintain a shared, current understanding of the mine plan and to keep permitting timelines predictable as the Project advances toward construction.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 18 | Page 2 I NTRODUCTION 2.1 R EGISTRANT This Technical Report Summary (this “Technical Report Summary,” “TRS” or “Report”) was prepared in accordance with Item 601(b)(96) and subpart 1300 of Regulation S-K (“Regulation S-K 1300”) promulgated by the United States Securities and Exchange Commission (“SEC”) for NioCorp Developments Ltd (“NioCorp” or “the Company”). The TRS was prepared by Qualified Persons listed in Section 1 for the proposed Elk Creek, Nebraska Critical Minerals Mine (the “Elk Creek Mine,” the “Elk Creek Project” or the “Project”), located in southeastern Nebraska. NioCorp is a publicly held company with its corporate office located at: 7000 S. Yosemite Street, Suite 115 Centennial, Colorado 80112 USA This Technical Report Summary summarizes the results of a pre-feasibility study (as that term is defined under Regulation S- K 1300) (the “2026 Elk Creek Study”) prepared by the Qualified Persons. The reason that the 2026 Elk Creek Study does not qualify as feasibility study under Regulation S-K 1300 is because additional work with respect to the engineering of and procurement for the planned surface plant is required to allow the Qualified Person to reduce the overall contingency range attributed to the initial capital expenditure estimate for the Elk Creek Project from the current 14% to less than or equal to 10%. 2.2 T ERMS OF R EFERENCE AND P URPOSE OF THE R EPORT This Technical Report Summary has been prepared for NioCorp in accordance with the requirements of Regulation S-K 1300. The purpose of the TRS is to provide a technical summary of the Elk Creek Project. The Elk Creek Project is an existing project for which previous exploration, drilling, geological interpretation, metallurgical testwork, engineering studies, and other technical evaluations have been completed. The current study incorporates the available historical information together with subsequent technical work and updated project assumptions considered appropriate as of the effective date of this TRS. The scope of the 2026 Elk Creek Study includes, as applicable, an update, review and evaluation of the geological database, data verification and quality assurance/quality control procedures, update of the Mineral Resource estimation and Mineral Reserve estimation, geotechnical and hydrogeological considerations, mining methods, metallurgical testwork, mineral processing and recovery methods, infrastructure requirements, environmental and permitting considerations, market assumptions, capital and operating cost estimates, and economic analysis. The conclusions and estimates presented in this TRS are based on information available to the Qualified Persons as of the effective date of June 30, 2026. The Qualified Persons have reviewed the information relevant to their respective areas of responsibility and consider the data and supporting technical studies adequate for the purposes of the disclosures presented in this TRS.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 19 | Page 2.3 S OURCES OF I NFORMATION The parties responsible for generating this TRS are listed on Page i. The sources of information provided by NioCorp and utilized in the preparation of this Report include: • Information on land ownership and land agreements in the Project Area • Information on permitting requirements for the Project and the status of the Company’s permitting efforts • Information related to NioCorp’s relationships with local community and community groups • Market reports and market data related to niobium, scandium, titanium and rare earth elements The Qualified Persons relied on certain information provided by the following persons in preparation of portions of this Technical Report Summary. The Qualified Persons responsible for the sections of this Technical Report Summary indicated below have reviewed and adopted such information and do not disclaim responsibility therefor. • Dr. Andrew Matheson, OnG Commodities – Sections 16.1.3 and 16.3.1 (Scandium Market) • Cari Anderson, SRK Consulting – Section 17.5 (Reclamation and Closure) • Mark Willow, SRK – Section 17.5 (Reclamation and Closure) • David Bird, M.Sc, PG, Consulting Hydrogeochemist, Section 17.2 (Waste Management and Disposal) External sources of information used to prepare the TRS are listed in Section 24 (References). 2.4 E FFECTIVE D ATE The overall effective date of this Technical Report Summary is June 30, 2026. 2.5 D ETAILS OF I NSPECTION A summary of the Qualified Persons that completed a site visit are summarized below in Table 2‐1. Table 2‐1: A summary of the site visit inspections by the QP consultants QP Company Expertise Date(s) of Visit Details of Inspection Anthony (Tony) Linton Dumas Contracting USA Inc. Mine Engineering March 10 to 11, 2026 View ongoing Portal Excavation Trevor Mills Dahrouge Geological Consulting USA Ltd. Geology Multiple times from April 24, 2025 through November 17, 2025 Review of drill core, review, verification of the geological setting / environment, logging, sampling, analytical, QA/QC, site facilities.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 20 | Page QP Company Expertise Date(s) of Visit Details of Inspection Jacob Andersdon Dahrouge Geological Consulting USA Ltd. Geology ResourcesSeptember 8 to 10, 2025 Review of drill core, review, verification of the geological setting / environment, logging, sampling, analytical, QA/QC, site facilities, drill collar locations Janine Brown Dahrouge Geological Consulting USA Ltd. Geology May 10 to 16, 2025 Review of drill core, review, verification of the geological setting / environment, logging, sampling, analytical, QA/QC, site facilities. Amélie C. Ouellet Andrieux & Associates Geomechanics Consulting Rock Mechanics May 13-14, 2025 Review of drilling operations and drill core logging Scott Britton Amplify Mine Planning Reserves/Mining March 30 to 31, 2026 Review of field operations, resource and reserve locations, property position Adrian Brown Adrian Brown Consultants Inc Hydrogeology July 25 to August 12, 2025; September 23 to September 25, 2025 Oversight of drilling operations related to hydrogeologic investigations and grouting test program. Troy Meyer Tierra Group/BBA Tailings January 22, 2026 Review of field operations, resource and reserve locations, property position Eric Larochelle SMH Process Innovation Hydrometallurgy & Process Engineering March 12, 2026 Review of field operations, resource and reserve locations, property position 2.6 Q UALIFICATIONS OF Q UALIFIED P ERSONS The Qualified Persons preparing this Report are specialists in the fields of geology, exploration, Mineral Resource and Mineral Reserve estimation and classifications, underground mining, mining backfill, geotechnical, environmental, permitting, metallurgical testing, mineral processing, processing design, pipeline design, capital and operating cost estimation, and mineral economics. None of the Qualified Persons, nor any associates involved in the preparation of this Technical Report Summary, holds any beneficial interest in NioCorp. The Qualified Persons are not insiders, associates, or affiliates of NioCorp. The conclusions and results presented in this Technical Report Summary are independent and are not influenced by any prior agreements regarding the outcomes to be reached, nor are there any undisclosed arrangements concerning future business dealings between NioCorp and the Qualified Persons. The Qualified Persons have been compensated for their services in accordance with standard professional consulting practices. Technical expertise and specialist services used in the preparation of this Technical Report Summary were provided by the Qualified Persons identified in Table 2-2. The areas of contribution included geology, exploration, Mineral Resource and Mineral Reserve estimation, mining, geotechnical
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 21 | Page engineering, environmental studies and permitting, metallurgy and mineral processing, infrastructure design, cost estimation, and mineral economics. The Qualified Persons, along with the sections of this Technical Report Summary for which they are responsible, are identified in Table 2‐2. Table 2‐2: List of Qualified Persons responsible for sections of this Report Qualified Person Sections Dahrouge Geological Consulting USA Ltd. 1.1 to 1.5, 1.7, 1.12, 1.17, 2, 3, 4, 5, 6, 7, 8, 9, 11, 16, 20, 22.1, 22.7, 23.1, 23.9, 24, and 25 SMH Process Innovation 1.6, 1.6.2, 1.10, 10, 10.1, 10.3, 14.1, 14.2, 14.2.2, 14.3, 14.3.2, 14.4, 14.4.2, 14.5, 14.5.2, 14.6, 14.6.2, 22.3, 22.4, 23.2, and 23.6 Dumas Contracting USA Inc. 13.4.5, 13.5.2, 13.7, 13.8, 13.9, 15.2.3, 15.2.4, and 15.6.1 Amplify Mine Planning LLC 1.8, 1.9, 12, 13.1, 13.4, 13.4.1, 13.4.2, 13.4.3, 13.4.4, 13.5, 13.5.1, 13.5.3, 13.5.4, 13.6, 13.6.1, 13.6.2, 13.6.3, 13.6.6 22.2 and 23.4 Tierra Group/BBA 1.11.1, 15.8, 15.9, 15.10, 15.11, 15.12, and 22.5.1, Olsson 1.13, 17, 22.6, and 23.8 Adrian Brown Consultants Inc. 13.3 Andrieux & Associates Geomechanics Consulting, L.P.13.2, 13.6.5, and 23.3 Tetra Tech 1.11, 14.7, 15.1, 15.2, 15.2.1, 15.2.2, 15.3, 15.4, 15.5, 15.6, 15.6.2, 15.7, 22.5, and 23.7 T Engineering 13.6.4 and 15.13 Magemi Mining Inc. 1.6.1, 10.2, 14.2.1, 14.3.1, 14.4.1, 14.5.1, and 14.6.1 Metallurgy Concept Solutions 1.6.3, 10.4, 14.2.3, 14.3.3, 14.4.3, 14.5.3, 14.6.3, and 23.5 Scott Honan, M.Sc., SME-RM, NioCorp 1.14 to 1.16, 18, 19, 21, and 22.8 As described in Section 2.3, the Qualified Persons reviewed and incorporated into their opinions and conclusions contained herein certain information that was provided to the Qualified Persons by NioCorp and others throughout the course of the investigations. The Qualified Persons used their experience to determine if the information from previous reports was suitable for inclusion in this Technical Report Summary and adjusted information that required amending. This report includes technical information, which required subsequent calculations to derive subtotals, totals and weighted averages. Such calculations inherently involve a degree of rounding and consequently introduce a margin of error. Where these occur, the Qualified Persons do not consider them to be material.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 22 | Page Except as specifically disclosed herein, the Qualified Persons have not independently verified legal, commercial, financial, taxation, permitting, or other non-technical information relied upon in this Technical Report Summary, nor have the Qualified Persons sought independent legal opinions regarding such matters. 2.7 U NITS OF M EASURE Unless otherwise noted, the following measurement units, formats and systems are used throughout this Report: • All references to measurement units use the Imperial System for measurement unless otherwise noted. • All references to orientation and coordinates in this Report are presented as UTM. • Currencies outline in this Report are stated in U.S. dollars (US$) unless otherwise noted. • Symbols and abbreviations used in this Report are outline in Section 24.2 3 P ROPERTY D ESCRIPTION & L OCATION 3.1 P ROPERTY L OCATION The Property is located in southeastern Nebraska, USA (Figure 3‐1M). The Property is situated within the United States Geological Survey (“USGS”) Tecumseh SE Quadrangle (7.5-minute series) mapsheet and encompasses Sections 1–6 and 9– 11, Township 3 North, Range 11 East, as well as Sections 19–23 and 25–36, Township 4 North, Range 11 East. The approximate center of the Project is located at UTM coordinates 739240 E and 4461282 N (NAD83, Zone 14N). The Project is located approximately 47 miles southeast of Lincoln, the state capital of Nebraska, and 68 miles south of Omaha, Nebraska. The nearest municipalities are Elk Creek, located approximately 3 miles east-northeast of the Property, and Tecumseh, located approximately 7 miles north of the Project. The mineralized body is located within Johnson County, Nebraska; however, NioCorp land ownership extends across both Johnson and Pawnee counties.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 23 | Page Source: DGC, 2026 Figure 3‐1: Project Location Map 3.2 M INERAL T ITLE AND L AND T ENURE The Property consists of a 709.93-acre (287.30 ha) parcel of land owned by the Company along with six option-to-purchase agreements covering approximately 1010.96 acres (463.72 ha). Option agreements are between NioCorp's subsidiary Elk Creek Resources Corp. (“ECRC”) and the individual landowners (Figure 3‐2). The surface and mineral rights owned by the Company were purchased in a series of transactions with landowners between 2021 and 2025. The parcel owned by the Company contains the Mineral Resources and Mineral Reserves associated with the Project. ECRC is a Nebraska-based wholly owned subsidiary of NioCorp. NioCorp retains 100% of the mineral rights to the Project and is the operator. The option agreements are in the form of pre-paid Exploration Lease Agreements (ELA), with an Option to Purchase (“OTP”) the mineral rights and/or the surface rights at any time during the term of the agreement. The individual landowners have title to the surface and subsurface rights, and the agreements are primarily concerned with only the mineral and surface interest of each property. The agreements convey to the Company adequate surface rights to access the land and to complete mineral exploration work. The parcels ECRC 5 and ECRC 1, of which the Company owns all surface and mineral rights, include all the Mineral Resources and Mineral Reserves described in this report. Active OTP agreements are listed in Table 3‐1.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 24 | Page Source: DGC 2026 Figure 3‐2: Project Tenure Map Table 3‐1: Active Option to Purchase Agreements Covering the Project Agreement Identifier Hectares Acres Agreement Expiry Beethe007 66.27 163.75 20-Jan-31 Heidemann005 79.55 196.57 16-Mar-30 Nielsen001 100.91 249.32 25-Jun-30 Woltemath002 152.49 376.81 4-Dec-29 Krueger001 32.78 63.79 12-Nov-30 Shuey001 32.37 80 27-May-40 Source: NioCorp 2026 The majority of the Mineral Resource is located on Company-owned parcels, and additional surface rights have been secured through OTP agreements as required. The Company’s land package provides sufficient area for mine waste and tailings disposal, a processing plant, and related infrastructure.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 25 | Page 3.2.1 Nature and extent of Issuer’s Interest The Company has secured surface rights under the exploration OTP agreements, allowing access for drilling and related exploration activities. Certain agreements also include mineral rights subject to a 2% NSR royalty, with options to acquire the surface rights, mineral rights, or both during the agreement term. 3.3 R OYALTIES , A GREEMENTS AND E NCUMBRANCES The leases covering the Property are 100% owned by NioCorp. Except for a 2% NSR royalty attached to the land owned by NioCorp and the OTPs that include the mineral rights, there are no other outstanding royalties, agreements, or encumbrances affecting the Property (Figure 3‐3). img170397038_3.jpg Source: DGC 2026 Figure 3‐3: Net Smelter Return (“NSR”) Map 3.4 E NVIRONMENTAL L IABILITIES AND P ERMITTING At this time, there are no known environmental concerns that would materially impact NioCorp’s ability to extract the mineral reserves or mineral resources near Elk Creek. Environmental permitting timelines at the state level require up to six months for processing of most individual permits, with roughly 18 months needed for solid waste permitting for tailings impoundments. Broadly speaking,
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 26 | Page general permits can be active within seven to 10 days of providing a full and complete application package Exploration work conducted to date on the Project has been completed under Exploration Permit NE0211001 issued by the Nebraska Department of Environment and Energy (“NDEE”). The permit provides the Company with the right to have ten open boreholes active at the Project at any given time. The Project will require various federal, state, and local permits for operations. Most permits are routine and involve standard applications and fees. Certain Nebraska permits, including a Solid Waste Permit and Air Operating Permit, are discretionary and require state approval. While the risk involved in such permits is low, such discretionary permits require more processing time by the state and do require the state agency to make a decision in favor of issuance of the permit. Permit costs and timelines are included in the Project execution plan. The Company has already received a Construction Air Permit from the State of Nebraska and a Special Use Permit from Johnson County, Nebraska. Details on the project’s permitting requirements can be found in Section 0 of this report. 3.5 O THER S IGNIFICANT F ACTORS AND R ISKS There are no known other significant factors or risks which could have a material impact on the ability to affect access, titles, or the right to perform exploration and development work on the Project.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 27 | Page 4 A CCESSIBILITY , C LIMATE , L OCAL R ESOURCES , I NFRASTRUCTURE AND P HYSIOGRAPHY 4.1 A CCESSIBILITY AND T RANSPORTATION TO THE P ROPERTY The Project is easily accessible year-round as it is situated approximately 47 miles southeast of Lincoln (State Capital), Nebraska and approximately 68 miles south of Omaha, Nebraska. Access to the site can be achieved via interstates and state highways from one of the regional airports. There are several regular scheduled flights to both Lincoln and Omaha (Figure 4‐1), with Omaha providing more regularly commercially serviced options. From Eppley Airfield in Omaha, Nebraska, the Project is accessed via paved roads by the following: • Abbott drive to Interstate I-480 for approximately 3.4 miles until exit 425C to merge onto Interstate I-80W towards Lincoln, Nebraska; • Then continue west on interstate I-80 for approximately 15 miles until exit 440 for state highway NE-50. • Then head south on State Highway NE-50 for approximately 62 miles through Tecumseh, Nebraska to the Project entrance. 38_4.jpg Source: DGC 2026 Figure 4‐1: Project Access
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 28 | Page 4.2 C LIMATE AND L ENGTH OF O PERATING S EASON Southeast Nebraska is situated in a Humid Continental Climate (Dfa) under the Köppen climate classification system. This climate is generally characterized by hot, humid summers and cold winters. Based on 1991–2020 climate normals for Tecumseh, Nebraska, average winter (January) temperatures are approximately 13°F to 35°F, while average summer (July) temperatures are approximately 65°F to 88°F. Average monthly precipitation (rain and liquid-equivalent snowfall) at the Tecumseh 1S station ranges from approximately 0.8 inches to 5.3 inches, with a mean annual total of approximately 32.3 inches (30-year “Normal”). Average annual snowfall in Tecumseh is approximately 22 inches. Exploration and mining-related activities may be conducted year-round, although severe winter weather and spring/early-summer thunderstorm activity can periodically affect operations. Nebraska is located within a region of the central United States that experiences severe thunderstorms and tornadoes, with peak tornado occurrence generally during May through July, although events can occur outside this period. 4.3 P HYSIOGRAPHY The local topography of eastern Nebraska is relatively low relief with shallow rolling hills intersected by shallow river valleys. Elevation varies from 1,066 ft to 1,276 ft (325 to 390 m) above mean sea level. Bedrock outcrop exposure is nonexistent in the Project area. Much of the Project area is used for cultivation of corn and soybeans, along with use as grazing land. Native vegetation typical of eastern Nebraska is upland tall-grass, prairie, and upland deciduous forests. 4.4 I NFRASTRUCTURE AND L OCAL R ESOURCES Technical and trades personnel can be sourced from local colleges and universities. An underground-experienced mining- related workforce can be found around Weeping Water, Nebraska as well as in neighboring states such as Salt Lake City, Utah, South Dakota and Denver, Colorado (eight hours drive west of the Project). Additional detailed information regarding specific infrastructure required for the Project can be found in Section 15.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 29 | Page 5 H ISTORY 5.1 E XPLORATION H ISTORY Regional airborne magnetic surveys were completed between November 1963 and January 1964 which identified regional features within southeast Nebraska. Further investigation of the Project was not completed until 1970 when a gravity survey was conducted by the Conservation and Survey Division (CS) of the University of Nebraska-Lincoln (“UNL”). Coinciding independent work was also being completed by the UNL geology department mapping the magnetic expression of the Nemaha Arch and Humbolt Fault systems. The comparison of the two surveys results identified a positive of the two geophysical survey results showed positive correlations between the magnetic and gravity anomalies which is now defined as the Elk Creek gravity anomaly (Anzman, 1976). The gravity survey outlined a near-circular anomaly, along with a concurrent magnetic anomaly, approximately 4.35 miles (7 km) in diameter. Analysis of the geophysical data provided a model of a cylindrical mass with of indefinite length with a radius of 5,500 ft (1,676 m) (Carlson & Treves, 2005). This early work resulted in early drilling by the Nebraska Geological Survey and the United States Bureau of Mines. In 1971, test hole 2-B-71 intersected carbonatite with pyrochlore mineralization and elevated niobium and rare earth elements, confirming the source of the anomaly. A private mineral leasing and exploration phase began in the early 1970s. Cominco American Inc. acquired mineral rights in 1973 and undertook exploration work, after which the rights were acquired by Molycorp in 1974. Molycorp completed detailed aeromagnetic surveying in 1973 and, in 1980, carried out a regional exploration program including gravity work, magnetic surveying, geologic mapping, surface sampling, and drilling. Between 1973 and 1986, Molycorp completed a regional drill program over an approximately 4.3 mi × 4.3 mi (7 km × 7 km) gravity anomaly, totaling 114 drill holes for approximately 157,992 ft (48,156 m). Within the Elk Creek Deposit area, 27 holes totaling 52,848 ft (16,108 m) were drilled during the 1970–1980 period, forming the foundation of the historical drilling database. The TRS notes that no known exploration was completed on the Property between 1986 and 2011. In 2010–2011, Quantum initiated verification and modernization of the historical dataset through DGC, compiling and checking historical drilling, lithology, and assay information, and completing resampling of historical material to assess comparability with historical results. Quantum then completed a 2011 diamond drilling program consisting of five inclined holes totaling 11,220 ft (3,420 m) of HQ core; three holes 7,605 ft (2,318 m) targeted the Elk Creek Deposit and two holes tested regional REE targets (not used in the Mineral Resource Estimate). Following acquisition, NioCorp advanced the project through additional diamond drilling programs to improve confidence and support updated technical studies. Between 2014 and 2015 NioCorp drilled a total of 24 holes within the Elk Creek Deposit totaling 63,389 ft (19,321 m). The program included data validation, metallurgical and mineralogical studies, geotechnical and hydrogeological studies all in support of resource estimation. Details of the program are provided in previous technical studies (Batty et al., 2022; Nordmin, 2019; SRK, 2014, 2015, 2017; Tetra Tech Wardrop, 2012). Table 5‐1: Historical Exploration Summary Year Company Exploration Work
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 30 | Page 1963-1964 US Geological Survey Regional Airborne Survey 1970 UNL Airborne Gravity & Magnetic Surveys 1971 Nebraska Geological Survey and the United States Bureau of Mines 1 Drill hole 2-B-71 (NN-1) 1973 Cominco American 4 Drill holes within the Carbonatite Complex 1973-1986 Molycorp 114 Drill holes within the Carbonatite Complex 2010-2011 Quantum Historical Data Verification; 5 Drill holes within Carbonatite Complex 2014-2015 NioCorp 24 Drill holes Source: Dahrouge 2026 5.2 O WNERSHIP H ISTORY Details of the original ownership of the complete Project area remain unclear; however, previous reports note that the initial land packages over the Project were controlled by Cominco American Inc. (“Cominco American”) and Molycorp Inc. (“Molycorp”) during the early 1970’s. Much of the historical exploration work completed over the Project area was done by Molycorp before 1984. On May 4, 2010, Quantum Rare Earth Developments Corp. (“Quantum”) announced the acquisition of the mineral rights to the Project and on March 3, 2013, Quantum announced an official name change to NioCorp Developments Ltd. (“NioCorp”). 5.3 H ISTORICAL M INERAL R ESOURCE E STIMATES Multiple historical resource estimates have been completed on the project and are detailed in the reports listed below. The previous resource estimate was completed by Understood Mineral Resources Ltd. in 2022. • Internal Molycorp Memo (Cook & Shearer, 1986) • Elk Creek NB Project, Nebraska, US Resource Estimate Update Tetra Tech Wardrop Estimate April 23, 2012 (Tetra Tech Wardrop, 2012) • NI 43-101 Technical Report on Resources Elk Creek Niobium Project, Nebraska (SRK, 2014) • NI 43-101 Technical Report Updated Preliminary Economic Assessment, Elk Creek Niobium Project, Nebraska (SRK, 2015) • NI 43-101 Technical Report Feasibility Study Elk Creek Niobium Project Nebraska NI 43-101 Technical Report Feasibility Study, Elk Creek, Superalloy Materials Project, Nebraska Nordmin Engineering April 16, 2019 (Nordmin, 2019) 5.4 H ISTORICAL M INERAL R ESERVE E STIMATES There is no historical reserve estimate on the Project. 5.5 H ISTORICAL P RODUCTION There has been no historical production at the Project.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 31 | Page 6 G EOLOGICAL S ETTING , M INERALIZATION AND D EPOSIT 6.1 R EGIONAL G EOLOGY The Nebraska Precambrian basement is comprised mainly of granite, diorite, basalt, anorthosite, gneiss, schist and clastic sediments. A series of island arcs sutured onto the Archean continent created the basic framework of the area. This suture left a north-trending intervening boundary zone ancestral to the Nemaha Uplift, providing a pre-existing tectonic framework which controlled the trend of the later Midcontinent Rift System (1.0 to 1.2 Ga) (Carlson & Treves, 2005). The Elk Creek Carbonatite is located at the northeast extremity of the Nemaha Uplift. The Midcontinent Rift System, or Keweenawan Rift, comprises mafic igneous rocks and forms a belt over 1,242 mi (2,000 km) long and 34 mi (55 km) wide that is exposed at the surface in the Lake Superior Region and extends southwards through the states of Michigan, Wisconsin, Minnesota, Iowa, Nebraska and into Kansas (Carlson, 1992). Both basalt and associated red clastic sedimentary rocks are found in the Precambrian basement of southeastern Nebraska. These rocks are very similar to those found in the Lake Superior region and are thus considered to be a product of the Keweenawan rifting (Burchett & Reed, 1967; Treves & Low, 1983). Figure 6‐1 illustrates the major rock types of the Midcontinental Rift system. The Nemaha Uplift (300 Ma) extends southward as a narrow belt from around Omaha, Nebraska across Kansas to around Oklahoma City, along the midcontinent rift system (King, 1969) (Figure 6‐1 and Figure 6‐2). Along the northern and eastern margins are complex fault zones and steeply dipping units. Regional north-northeast to northeast striking faults are locally transected by northwest trending ones, including the Central Plains mega-shear (Central Missouri Fault) to the north and the Oklahoma mega shear to the south (McBee, 2003). The Elk Creek Carbonatite body intruded near to the axis of the Nemaha uplift and has similar age dates to a cluster of carbonatites north of Lake Superior that are in the range of 560 to 580 Ma. (Erdosh, 1979; Woolley, 1989). Temporally, the carbonatite occurs near the boundary between the Penokean Orogen (approximately 1,840 Ma) and the Dawes terrane (1,780 Ma) of the Central Plains Orogen (Carlson & Treves, 2005). Regional geophysical data and drilling have confirmed the presence of kimberlitic intrusive bodies in northern Kansas to the southwest of the Elk Creek Carbonatite. These kimberlites were emplaced along the rift system during the Cretaceous time (Berendsen, P. & Weis, 2001). The eastern portion of Nebraska was glaciated several times throughout the early Pleistocene (Wayne, 1981), resulting in the deposition of up to 164 ft of unconsolidated till. Figure 6‐2 shows a merged airborne magnetic anomaly map of Nebraska, Kansas, and Oklahoma states (Sweeney & Hill, 2005) showing the Midcontinent Rift and Nemaha Uplift systems.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 32 | Page Source: Modified from (Palacas et al., 1990) Figure 6‐1: Regional Geology
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 33 | Page Source: Modified from Sweeney and Hill, 2005 Figure 6‐2: Merged Aeromagnetic Anomaly Map of Nebraska, Kansas and Oklahoma showing Midcontinental Rift and Nemaha Uplift 6.2 P ROPERTY G EOLOGY The Property includes the carbonatite that has intruded older Precambrian granitic and low- to medium-grade metamorphic basement rocks. The carbonatite and Precambrian rocks are unconformably overlain by approximately 656 ft (200 m) of Paleozoic marine sedimentary rocks of Pennsylvanian age ranging from ca. 299 to 318 Ma.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 34 | Page Source: Modified from KGS O-F Report 91-52 Figure 6‐3 Generalized Stratigraphy of the Elk Creek Area As a result of this thick cover, there is no surface outcrop within the Project area of the carbonatite, which was identified and targeted through magnetic surveys and confirmed through subsequent drilling. The available magnetic data indicates dominant northeast, west-northwest striking lineaments and secondary northwest and north-oriented features that mimic the position of regional faults parallel and/or perpendicular to the Nemaha Uplift (Figure 6‐2). Previous technical report summaries interpreted the contact between the Elk Creek carbonatite and the Pennsylvanian sedimentary sequence as a sheared and oxidized contact zone, suggesting an intrusive relationship between the carbonatite and the Pennsylvanian strata, and described associated brittle to brittle-ductile deformation features (tension veins, sheared veins, and slickensided fault planes) affecting both units (Batty et al., 2022). Based on subsequent review of drill core and the sub-horizontal, planar geometry of the broken rubble zone at the contact, the current interpretation is the Pennsylvanian– carbonatite boundary is an erosional unconformity rather than a shear-generated contact. This revised interpretation is consistent with the regional framework described by Carlson and Treves (2005), who concluded that uplift on the Nemaha Uplift was followed by significant erosion that likely truncated (beveled) the top of the carbonatite body, prior to reburial beneath Upper Pennsylvanian marine sediments. Under the revised model, the “brecciated limestone” immediately above the carbonatite is interpreted as a basal Pennsylvanian
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 35 | Page unit formed by transgressive–regressive reworking and erosion during early Pennsylvanian deposition, rather than as a product of shearing along the contact (Figure 6‐4). Brittle faults, veins, and related deformation features described previously remain recognized in core (Figure 6‐4); however, they are interpreted as superimposed structural features that may locally modify the contact zone but are not considered the primary process responsible for formation of the unconformity. Source: NioCorp 2025; SRK 2014 Figure 6‐4: (Left) Drill core illustrating the transition from eroded paleosurface of the Elk Creek Carbonatite Complex to the “Limestone Breccia”. (Right) Photographs of microstructures in the drill core. 6.2.1 Marine Sedimentary Rocks The state-wide Nebraska test hole database contains information for about 5,500 test holes drilled since 1930 by the CSD (Conservation and Survey Division of the University of Nebraska-Lincoln (UNL), School of Natural resources (SNR), (UNL- CSD/SNR), and cooperating agencies. Test hole
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 36 | Page location data, as well as lithological descriptions, stratigraphic interpretations, and geophysical log records, are included in the database. In addition, UNL-CSD/SNR maintains an extensive collection of geologic samples obtained from the drilling process (UNL-CSD/SNR website). There are active limestone quarries, and underground mines within approximately 43 miles of the Project site that create road materials, lime, fill, and construction materials. These quarries are actively mining approximately 2.2 million tons/year from within the Pennsylvanian limestone units. The Pennsylvanian limestone unit is the same as is currently located above the carbonatite unit at the Project site. 6.2.2 Elk Creek Carbonatite The Elk Creek Carbonatite Complex is an elliptical magmatic body with a northwest-trending long axis perpendicular to the strike of the 1.1 Ga Midcontinent Rift System (Figure 6‐1 and Figure 6‐2), near the northern part of the Nemaha uplift (Burchett, 1982; Carlson, 1992). The definitive confirmation of carbonatite was completed using Rare Earth Element (REE), P2O5 and Sr87/Sr86 isotope analysis (Brookins et al., 1975). The carbonatite has also been compared to the Iron Hill carbonatite stock in Gunnison County, Colorado, based on similar mineralogy (Xu, 1996). The lithological units present in the carbonatite complex were originally defined by Molycorp during their drill programs, additional studies by Xu in 1996 based on select drillholes (2-B-71 (also known as "NN-1"), EC-40, EC-42, EC-50, EC-70, and EC- 82) and were further simplified by DGC for interpretation purposes during each stage of the Project (2011, 2014, 2025). The carbonatite phase was classified into two main units (defined by texture, massive or brecciated) and several sub- units including a massive carbonatite (dolomite carbonatite, apatite bearing dolomite carbonatite and pyrochlore-bearing Carbonatite, apatite dolomite carbonatite, hematite dolomite carbonatite and magnetite dolomite carbonatite) and brecciated carbonatite. Xu (1996) also classified several silicate units including an altered basalt, altered lamprophyre and altered syenite. During the 2014, 2015 and 2025 drilling campaigns, DGC geologists split the dolomite carbonatite (“dolCarb”) units down into a number of key units using the information of the different phases of carbonatite. The main carbonatite lithologies used for geologic interpretation are: • Dolomite Carbonatite – dolCarb • Dolomite Carbonatite Breccia – dolCarbBc • Hematite Dolomite Carbonatite – hemdolCarb • Magnetite Dolomite Carbonatite – mdolCarb • Magnetite Dolomite Carbonatite Breccia – mdolCarbBc DGC considers the more detailed split of the carbonatite units for geologic interpretation to be relevant to determining the distribution of different grade populations as supported by statistics (discussed in Section 8.3). The most significant difference is the change in the logging codes between dolCarb and mdolCarb, in terms of the major rock types. Summarized below in Table 6‐1 are the lithological units captured from compiled drillhole logs and corresponding geology reports, and the nomenclature applied by DGC. Table 6‐1: Project rock types as defined by Molycorp and DGC Unit Name (Molycorp) Code Unit Name (DGC) Code Overlying Lithologies
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 37 | Page Unit Name (Molycorp) Code Unit Name (DGC) Code Quaternary sediments Qt Overburden (~165 ft) Ovb Pennsylvanian Sediments Pu Pennsylvanian Sediments (~656 ft thick)sed Elk Creek Complex Younger Mafic Rock ym Mafic Breccia mafBc Barite Beforsite III bb III Barite Dolomite Carbonatite dolCarb Barite Beforsite II bb II Beforsite Breccia bbx Dolomite Carbonatite Breccia dolCarbBc Barite Beforsite I bb I Barite Dolomite Carbonatite dolCarb Apatite Beforsite II ab II Apatite Dolomite Carbonatite Breccia dolCarb Apatite Beforsite I ab I Older Mafic Rock om Mafic dyke, vein or fragment maf Lamprophyre Lamp Magnetite Beforsite mb Magnetite Dolomite Carbonatite mdolCarb Syenite II sy II Syenite sy Syenite I sy I Host Rocks Granite/Gneiss pCgg Granite/Gneiss gn Amphibole Biotite — Gneiss pCbg Amphibole Biotite — Gneiss gn Source: DGC 2026 Limited age dating of the Elk Creek Carbonatite has been carried out with recent U-Pb zircon dates from the carbonatite ranging from 480 ±20 to Ma 540 ±14 (Farmer et al., 2013). The carbonatite consists predominantly of dolomite, calcite and ankerite, with lesser chlorite, barite, phlogopite, pyrochlore, serpentine, fluorite, sulphides and quartz (Xu, 1996). The stratigraphic reconstruction based on drill core observation in the area suggests that the carbonatite is unconformably overlain by approximately 656 feet (200 meters) of essentially flat-lying Palaeozoic marine sedimentary rocks, including carbonates, sandstones, and shales of Pennsylvanian age (ca. 299 to 318 Ma). 6.2.3 Structural Geology Based on data provided to carry out the structural study, the Project contains five main sets of brittle faults variably cutting through the Pennsylvanian rocks and the carbonatite boundary which appears to be tectonic. The orientations of the faults were determined by comparing Acoustic Televiewer (“ATV”) logs with specific customized structural core logging data, and by undertaking a preliminary interpretation of the provided geophysics images. This data has been used to model the fault pattern in 3D for use in further resource estimation and geotechnical studies. The overall fault model included approximately 28 structures with the vicinity
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 38 | Page of the Project with varying levels of confidence. Based on a review within the mineralization, at least three key northeast- trending faults have been identified and used during the geological modeling process. The joints and veins define orientation sets comparable to the fault trends. Hematite veins, which may be up to 3.28 feet (one meter) thick, represent the weakest fault- and joint-infilling material which may be problematic for mining and should, therefore, be given more attention during any future geotechnical studies. 6.3 M INERALIZATION The Property hosts niobium, titanium, and scandium mineralization as well as REE and barium mineralization that occur within the Elk Creek Carbonatite. In this TRS, niobium, titanium, scandium, and rare earth elements are considered the main elements of interest. The current extent of modelled mineralization is 3,937 ft (1,200 m) along strike, 1,640 ft (500 m) wide, and 2,461 ft (750 m) in dip extent below the unconformity. Previous reports found that that the mineralization is open in all directions. The recent drilling reported in this report indicates that there is a hanging wall contact between the Nb-Ti-Sc rich magnetite-dolomite- carbonatite lithology and the surrounding dolomite carbonatite to the south of the deposit, demonstrated in Figure 6‐5 and Figure 6‐6. Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 39 | Page Figure 6‐5: Plan view of the location of the mineralized carbonatite (outlined in red) with underground development projected to surface Source: DGC 2026 Figure 6‐6: Plan and Cross -Sections of Geologic Model Hanging Wall Boundary and Mineralized Domain 6.3.1 Niobium and Titanium Mineralization The deposit contains significant concentrations of niobium. Based on the metallurgical test work completed to date at several laboratories using QEMSCAN® analysis, the niobium mineralization is known to be fine-grained, and that 77% of the niobium occurs in the mineral pyrochlore, while the balance occurs in an iron-titanium-niobium oxide mineral of varying composition. Distribution and
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 40 | Page statistical review of Nb2O5 within the mineralized carbonatite, are shown in Figure 6‐7 and discussed in Section 6.4 and Section 11. Figure 6‐8 demonstrates that there is a fairly high correlation between increasing Nb2O5 grade and Fe2O3 and TiO2 grades. Source: DGC 2026 Figure 6‐7: Basic Statistics of Nb2O5 Mineralization Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 41 | Page Figure 6‐8: Correlation Statistics of Nb2O5 and TiO2 and Fe2O3 6.3.2 Scandium Mineralization Within the Elk Creek Carbonatite, a host of other elements exist with varying degrees of concentration. The Company has completed both whole rock analysis and multi-element analysis on all samples for the 2014 program, plus re-sampling programs of selected historical core and/or pulps between 2011 and 2021. As the metallurgical test work advanced during 2014 and 2015, the ability to obtain a titanium dioxide (TiO2) and scandium (Sc) product became apparent. TiO2 is strongly and positively correlated with niobium grades, whereas the scandium mineralization is spatially related to niobium and titanium mineralization, but with lesser degree of correlation. Basic statistics for Sc mineralization are shown in Figure 6‐9. Detailed discussion is presented in Section 14. Source: DGC 2026 Figure 6‐9: Basic Statistics of Sc Mineralization 6.3.3 Rare Earth Element Mineralization Within the Elk Creek Carbonatite complex, there are several occurrences of REE mineralization, including the Project area. REE mineralization is associated with a barite dolomite carbonatite and occurs within the following minerals: • Bastnäsite ([Ce,La,Y]CO3F) • Parisite (Ca[Ce,La]2[CO3]3F2) • Synchysite (Ca[Ce,La][CO3]F) • Monazite ([Ce,La]PO4)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 42 | Page Based on an excerpt from Molycorp’s drill logs: “Lanthanide minerals occur as radial patches and random aggregates of needles, irregular patches and vein-like aggregates. The aggregates occur with and without quartz. The aggregates appear as light-gray patches in reddish-brown, hematite-altered beforsite. Although individual lanthanide mineral grains are in the micrometer size range, aggregates of lanthanide minerals range from 0.23 to 8 mm. in maximum dimension. Monazite and bastnäsite have been identified in the aggregates, and EDX spectra show Ce > La." Present day nomenclature for REE is shown in Table 6‐2. Promethium (Pm) is not included as it is very rare in nature. The division into light and heavy rare-earth elements made below is based on differences in processing. Elsewhere in literature, the division has been made between gadolinium and terbium (atomic number 64 and 65) based on the lack of paired electrons in the inner incomplete subshell (4f) (Van Gosen et al., 2017). Statistical analysis of distribution and correlation of REEs within the deposit are presented in Section 11. Table 6‐2: List of Elements & Oxides Associated with REE Mineralization Element Element Acronym Compound Associated Elements and Oxides Nb NbONiobium Light Rare Earth Metals and Oxides (LREO) Lanthanum La La0 Cerium Ce Ce0 Praseodymium Pr Pr0 Neodymium Nd Nd0 Heavy Rare Earth Metals and Oxides (HREO) Samarium Sm SmO Europium Eu Eu0 Gadolinium Gd Gd0 Terbium Tb Tb0 Dysprosium Dy Dy0 Holmium Ho Ho0 Erbium Er Er0 Thulium Tm Tm0 Ytterbium Yb Yb0 Lutetium Lu Lu0 Yttrium Y Y0 Source: DGC 2026 6.4 D EPOSIT T YPE The Project is hosted within the Elk Creek Carbonatite. By definition, a carbonatite is an igneous rock body with greater than 50% modal carbonate minerals, mainly in the form of calcite, dolomite, ankerite, or sodium- and potassium-bearing carbonates. Carbonatites commonly occur as intrusive bodies, such as isolated sills, dykes, or plugs, although they can rarely occur as extrusive rocks (Oldoinyo Lengai, Tanzania). Many carbonatites are associated with alkalic silicate complexes which include syenite, nepheline syenite, ijolite, urtite, and pyroxenite. Carbonatites are generally related to large-scale, intra-plate fractures, grabens, or rifts that correlate with periods of extension, and 2 5 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 43 | Page range from Precambrian to recent in age. They are usually surrounded by an aureole of metasomatically altered rocks called fenites. Carbonatite-associated deposits can be classified as magmatic or metasomatic types (Richardson & Birkett, 1996). Carbonatites have been classified based on chemical classification into four classes (Woolley and Kempe, 1989; Wyllie and Lee, 1998), and further subdivided based on mineralogical and textural characteristics: • Calcio-carbonatite coarse-grained: sövite, and finer-grained: alvikite • Magnesio-carbonatite dolomite-rich: beforsite, and ankerite-rich: rauhaugite • Ferro-carbonatite (iron-rich carbonates) • Natro-carbonatite (sodium-potassium-calcium carbonates) The use of a chemical classification of carbonatites should be used with caution when replacement, or metasomatic, processes have altered the primary composition of the carbonatite rock (Mitchell, 2005). The majority of carbonatite deposits are located within stable, intra-plate crustal units, although some are linked with orogenic activity or plate separation. It is also important to note that carbonatites tend to occur in clusters, and in many places, there has been a repetition of intrusive activity over time (Woolley, 1989). Carbonatite-hosted deposits occur almost exclusively in intrusive carbonatite and may be subdivided into magmatic, replacement/veins, and residual sub-types. The Elk Creek Carbonatite can be classified as a magmatic sub-type, similar to the St-Honoré deposit in Quebec, Canada (Niobec niobium mine, Iamgold – Figure 6‐10), the Mountain Pass Deposit in California, U.S.A. (REE), and the Palabora Deposit in South Africa (apatite). The pipe-like carbonatites typically occur as sub-circular or elliptical shapes and can be up to 1.9-2.5 mi (3-4 km) in diameter. Magmatic mineralization within pipe-like carbonatites is commonly found in crescent shaped, steeply dipping zones. As carbonatite magma is typically volatile rich with low viscosity, it may ascend rapidly through the mantle, fracturing the crust on impact, causing a characteristic alternating ring (crescent) structure of carbonatite and wall rock to be formed. Metasomatic mineralization occurs as irregular forms, breccias, or veins. Carbonatites typically consist of multiple phases of intrusion with different mineralogical and textural characteristics. Early phases tend to consist mainly of calcite with later phases mainly consisting of dolomite, ankerite, or siderite. The later phases are typically more enriched in niobium or tantalum with the latest phases more enriched in rare earth minerals. In general, geochemical zonation of phases begin with calcio-carbonatite intrusion, followed by magnesio-carbonatite and finally ferro-carbonatite. Fenitization (alkali metasomatism) is common around many carbonatite intrusions.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 44 | Page Source: Jaroslav 2025 (Modified after Valliéres et al. (2013)) Figure 6‐10:Schematic Diagram of St. Honoré Carbonatite The major mineral constituents are calcite, dolomite, siderite, ferroan calcite, ankerite as carbonates, and hematite, biotite, titanite, olivine, and quartz. Economic minerals include fluorite (F), apatite (P), pyrochlore (Nb), anatase (Ti), columbite (Nb- Ta), monazite (REE), bastnaesite (REE), parasite (REE), zircon (Zr), and magnesite (Mg), among others. Mineralization within carbonatites is typically syn- to post-intrusion. The mineralization is controlled primarily by fractional crystallization within the intrusion, with tectonic and local structures influencing the form of metasomatic mineralization (Birkett & Simandl, 1999; Richardson & Birkett, 1996; Woolley & Kempe, 1989). Worldwide, carbonatite deposits are mined for niobium, REE, iron, copper, phosphate (apatite), vermiculite and fluorite; with barite, zircon/baddeleyite, tantalum and uranium as common by-products (Richardson & Birkett, 1996).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 45 | Page 7 E XPLORATION AND D RILLING 7.1 E XPLORATION Regional airborne magnetic surveys in 1963–64 first identified geophysical features in southeast Nebraska, followed by a 1970 gravity survey by UNL's Conservation and Survey Division that, combined with concurrent UNL mapping of the Nemaha Arch and Humboldt Fault systems, revealed a positive correlation between magnetic and gravity anomalies now known as the Elk Creek gravity anomaly. This anomaly was modeled as a near-circular feature roughly 4.35 miles (7 km) in diameter, corresponding to a cylindrical mass of indefinite length with a 5,500 ft (1,676 m) radius. This work prompted early drilling by the Nebraska Geological Survey and U.S. Bureau of Mines, and in 1971 test hole 2-B-71 intersected carbonatite with pyrochlore mineralization and elevated niobium and rare earth elements, confirming the anomaly's source. The carbonatite complex is a 3.7-4.9 mi (6–8 km) diameter alkaline intrusive body buried beneath roughly 656 ft (200 m) of Pennsylvanian marine sedimentary rocks with no surface expression, meaning exploration has relied entirely on geophysics and drilling. It comprises several lithologies dominated volumetrically by apatite dolomite, with the magnetite dolomite unit — though volumetrically minor — serving as the primary host of niobium mineralization (Figure 7‐1). Source: Drenth 2014 Note: (1) The term beforsite used in this figure has been superseded by the terms magnesio-carbonatite or dolomite carbonatite. Other rock-type names have been modified subsequently (see Table 6‐1). Figure 7‐1: Geology of the Elk Creek Carbonatite as expressed in drill holes at an elevation of 394 ft (120 m) AMSL (approximately 755 ft or 230 m BGS)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 46 | Page There is no other relevant exploration work outside of drilling completed on the Property on behalf of current and previous owners. Detailed descriptions of the geotechnical data, testing and analysis are included in Section 13.2. Descriptions, characterization and analysis of hydrogeology are included in Section 13.3. 7.2 D RILLING Mineral Resource definition drilling on the Project has been conducted in four phases: • Phase I: Drilling Campaigns completed during the 1970s and 1980s by MolyCorp. • Phase II: Initial Restart Drilling completed in 2011 by Quantum (NioCorp’s predecessor). • Phase III: Focused Resource Drilling completed in 2014 & 2015 by NioCorp. • Phase IV: Focused Resource Drilling completed in 2025 by Niocorp. To date, 94 drill holes have been completed on the Project for a total of 196,114 ft (59,775 m) (Figure 7‐2; Table 7‐1), including 16 drill holes totaling 37,861 ft (11,540 m) completed in 2025. A further five holes totaling 11,598 ft (3,353.1 m) were drilled in 2015 for hydrogeological and geotechnical studies but were not used for resource estimation. All drilling has been completed using a combination of tricone, reverse circulation (RC) or diamond drilling (DDH) core in the upper portion of the hole within the Pennsylvanian sediments. A portion of the 2014 drill holes used RC drilling within the Pennsylvanian sediments to increase drilling efficiency through cover material within areas of strong geological confidence. All drilling within carbonatite has been completed using diamond coring methods. To date, local labor has been used by drilling contractors when preparing the drill hole pads. All drilling has been completed using standardized procedures which are in line with international standards of best practice. The drilling by Molycorp was completed using company-owned equipment and sampling procedures. The drilling companies used by the Company between 2011 and 2015 programs are detailed below: • 2011: Black Rock Drilling, LLC (BRD Personnel and Leasing Corp.), 17525 E Euclid Ave, Spokane Valley, WA 99216 • 2014: Envirotech Drilling LLC, 900 East 4th Street, Winnemucca, NV 89445 • 2014: West-Core Drilling, LLC, 561 W Main Elko, NV 89801 USA; and • 2014: Idea Drilling, 1997 9th Avenue North, Virginia, MN 55792 • 2015: Idea Drilling, LLC, 1997 9th Avenue North, Virginia, MN 55792 • 2015: Envirotech Drilling LLC, 900 East 4th Street, Winnemucca, NV 89445 Table 7‐1: Drilling Completed within the Carbonatite Complex Year Company Number of Holes in Carbonatite Complex Number of holes on Project Project Hole Average Depth (m) Project Hole Average Depth (ft) Total Length (ft) Drillholes on Project Total Length (m) Drillholes on Project 1971-1986 Molycorp 114 49 530 1,738 85,171 25,960 2011 Quantum 5 4 739 2,423 9,692 2,954 2014-2015 NioCorp 24 24 805 2,641 63,390 19,321 2025 NioCorp 17 17 679 2,227 37,861 11,540
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 47 | Page Subtotal: 160 94 688 2,257 196,114 59,775 Source: DGC 2026 Source: DGC 2026 Figure 7‐2: All drilling completed within the area of the Elk Creek Carbonatite Complex During 2015 five holes (NEC15-001 to NEC15-005) were completed totalling 11,001 ft (3,353.1 m) for hydrogeological and geotechnical studies. The drilling was carried out by Idea Drilling and Envirotech Drilling LLC with Envirotech Drilling LLC as subcontractor. Not all the drill holes within the Project were used in the 2026 Mineral Resource Estimation, as many do not intersect the Nb2O5 anomaly and are located a significant distance away from the Deposit (Figure 7‐2). A total of 79 drill holes has been drilled within the Project, of these 65 drill holes were used to inform the Elk Creek Deposit Mineral Resource Estimation (Figure 7‐3). Note that there are more holes within the Project area, but some holes were excluded from the Mineral Resource as they were drilled for other purposes (geotechnical, hydrogeology) and were not sampled. A summary of the drilling in the Project area can be seen in Figure 7‐2.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 48 | Page Source: DGC 2026 Figure 7‐3: 2025 Drillhole locations on the Project The 2025 drilling program was specifically designed to target gaps within the current Mineral Resource in support of converting a portion of the Resource from Indicated and Inferred to Measured, Indicated and Inferred. The drilling for the 2025 program was completed by Boart Longyear Company – Western Coring, 7013 West Augusta Ave, Glendale, Arizona 85303. Drilling was initiated on April 29, 2025, and was completed on October 3, 2025. During this campaign a total of 16 HQ diameter drillholes were completed totalling 37,861 ft (11,540 m) utilizing 2 (two) LF-160 drill rigs, one track mounted and one truck mounted core drill. All drilling was completed using diamond coring methods (Figure 7‐2). Overburden was cased using HWT casing, and the remainder of the drillholes were completed using HQ thereafter. Table 7‐2: 2025 Drill Hole Summary Drill hole ID Easting Northing Elevation (m) Length Azimuth Inclination Comments NEC25-024 739068.9 4461370.1 350.7 740.7 118 -81 NEC25-025 739201.9 4461347 354.9 935.6 300 -85 NEC25-026 739002.9 4461298.9 349.8 920.8 30 -80
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 49 | Page Drill hole ID Easting Northing Elevation (m) Length Azimuth Inclination Comments NEC25-027 739217.1 4461460 353.5 859.8 182 -83 NEC25-028 739000.9 4461296.2 349.8 229.1 30 -63 Lost hole. NEC25-028a 739000.6 4461295.6 349.8 410.6 30 -63 Re-drill of NEC25-028 NEC25-029 739182 4461456.5 355.4 850.7 205 -80 NEC25-030 739478.9 4461193 345.5 768.7 280 -75 NEC25-031 739074.8 4461223.2 347.9 292.1 20 -65 NEC25-031a 739074.8 4461223.2 347.9 545.9 20 -65 Wedge: NEC25-031. NEC25-032 739309.6 4461173.3 344.5 801.6 25 -85 NEC25-033 739448.9 4461218.6 347.8 900.7 290 -68 NEC25-034 739444.9 4461139.4 341.7 451.4 30 -75 NEC25-035 739494.9 4461120.7 340.8 431.3 30 -80 NEC25-036 739524.2 4461088.2 340.6 451.5 30 -75 NEC25-037 739489.6 4460945.9 340.5 1,000.10 295 -65 NEC25-038 739075.6 4461210.1 347.5 949.4 320 -80 Source: DGC 2026 7.2.1 Project Drilling Procedures Historical Molycorp drilling (1970s–80s) was never reviewed by DGC, though presumed to reflect era-appropriate industry practice, while the 2011 Quantum program and all NioCorp drilling since 2014 were managed under consistent DGC/SRK quality control protocols. Drill collars were staked and oriented using GPS, compass, and Azimuth Pointing System equipment, with core drilled by West-Core, Idea Drilling, and Boart Longyear and transitioned from PQ to HQ size beneath the Pennsylvanian-carbonatite contact; completed holes were either piezometer-equipped or grouted and abandoned per standard procedure. Eight of the 2014 drill holes were completed with piezometers using locking steel casing, cement pads, and identification nameplates, while the remaining holes were marked with steel posts and nameplates noting hole number, depth, and orientation. All non-piezometer holes were abandoned with grout from total depth to the Pennsylvanian contact and cemented to surface, while piezometer holes were grouted from total depth to the base of the piezometer. 7.2.1.1 Collar and Downhole Surveys Drill collar locations were surveyed by ESP, Inc., Jorgensen Surveying, and CES Group using GPS/RTK equipment with horizontal accuracies of approximately 10–11 mm, referenced to NAD83(2011)/NAVD88, with historical Molycorp and 2011 collars re-excavated and re-surveyed as needed. Downhole survey methods evolved from compass readings historically, to Devico DeviFlex
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 50 | Page surveys in 2011, to Reflex GYRO surveys in 2014 (chosen to avoid magnetic interference from deposit mineralogy), to TruGyro gyrocompass surveys in 2025 at 50–100 ft intervals, all using non-magnetic tools appropriate to hole lengths exceeding 2,300 ft (700 m). 7.2.1.2 Geomechanical Core Logging Geomechanical logging was performed by DGC personnel under direction of A2GC, following a project-specific manual and on-site training in May 2025, using the Q-system (Barton, 1974) to assess rock mass quality. Recorded parameters included RQD, joint characteristics, fracture data, and lithological/alteration data, entered into a customized MX Deposit database. Additionally, geomechancial core logging data was also collected in 2014 and 2015 under the supervision of SRK. 7.2.1.3 Geological Core Logging The Qualified Person has reviewed the drilling, surveying, and core-logging procedures used across the 2011, 2014, and 2025 programs and considers them adequate and consistent with industry-standard practice to support Mineral Resource estimation, including collar and downhole survey methods, geomechanical logging, and geological logging and sample QAQC procedures. Historical Molycorp drilling and survey data (1970s–80s) have not been independently verified by the QP unless otherwise discussed in Section 8 and are relied upon with correspondingly reduced confidence due to their age, wider measurement spacing, and use of older equipment. The QP considers the sampling, security, and data verification methods described in this section adequate to support the reliability of the analytical results used in Mineral Resource estimation, consistent with the internal controls disclosure required under § 229.1305.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 51 | Page 8 S AMPLE P REPARATION , A NALYSES & S ECURITY 8.1 S AMPLE P REPARATION & S ECURITY In 2025, drill core was transported daily to the Project core processing facility in the core boxes for logging, photographing, sampling, and storage. Diamond drilling was monitored by DGC geologists and trained geological staff, with professional oversight provided by DGC. Standardized logging codes and lithological descriptions, developed from historical procedures, were used to maintain consistency between logging geologists. Geological observations, including lithology, texture, structure, mineralization, alteration, and color, were recorded by sample interval in the MX Deposits database. Drill core was digitally photographed at high resolution before cutting. Sample intervals were generally 3.28 ft (1 m) long and were assigned unique sample numbers. Specific gravity measurements were collected at approximately 19.67 ft (6 m) intervals. HQ core was split in half along orientation marks using water-cooled diamond saws. Broken or soft intervals were split as evenly as practicable. Split core was cleaned before bagging, and cutting equipment was routinely cleaned between samples. Samples were placed in labelled, barcoded sample bags containing backup sample tags. Original samples and field-inserted control samples were scanned, secured in five-gallon shipping pails, and accompanied by hard-copy and digital shipping records and laboratory preparation instructions. Samples were transported to the analytical laboratory by bonded carrier. The remaining half-core was retained in labelled core boxes and securely stored at the Project site for reference and potential future sampling. Sample security measures included redundant sample identification, secure bag closures, controlled storage, and shipment in sealed pails. The authors consider these procedures consistent with industry practice for a project of this scale. The sampling, preparation, and shipment procedures were standardized and monitored to minimize sample identification and handling errors. The on-site geologist managed the QA/QC program, which included certified reference materials, quartz blanks, field duplicates, coarse-reject duplicates, pulp duplicates, and external check analyses. Samples were prepared and analyzed at SGS and Activation Laboratories, with selected samples submitted for secondary check analysis. The data collection from the processed drill core is outlined in Figure 8‐1 process flow.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 52 | Page Source: DGC 2014 Figure 8‐1: Sample Process Flow Chart (2014 - 2025 drill programs) Source: NioCorp 2026 Figure 8‐2: NioCorp Technicians cutting core at the project site.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 53 | Page Source: NioCorp 2026 Figure 8‐3: Secure storage of the NioCorp Drill holes and pulps. 8.2 S AMPLE A NALYSIS P ROCEDURES Analytical methods used during the program included fusion XRF, fusion ICP-MS, and sodium peroxide fusion ICP-MS/ICP- OES methods available from SGS and Act labs. The recommended methodologies each have differences in the sample decomposition technique, analytical finish, and intended concentration range, and are applicable to the mineralization. The results generated by different laboratories and methods were compared with consideration of method-specific digestion efficiency, detection limits, upper reporting limits, and the mineralogical deportment of the elements of interest. Table 8‐1: Analytical methods used for sample assay. Company Method Decomposition Finish Use Act labs FUS-XRF Lithium borate fusion XRF Whole rock / major oxides Act labs FUS-MS Lithium borate fusion ICP-MS Trace elements / REE / HFSE SGS GC_XRF72MET Borate fusion XRF Metallurgical / concentrate-grade material SGS GC_XRF76V Borate fusion XRF Ore-grade / overlimit XRF SGS GE_IMS91A50 Sodium peroxide fusion ICP-MS Trace-level refractory elements SGS GE_ICP91A50 Sodium peroxide fusion ICP-OES / ICP-AES Higher concentration multi-element work Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 54 | Page The selected analytical methods are considered appropriate for the sample material and elements reported. The method- specific detection limits, overlimit procedures, and QAQC performance are reviewed accordingly. Overall, the analytical methods reviewed are considered appropriate for the elements and sample types reported; however, comparisons between laboratories should be assessed with reference to the specific decomposition method, analytical finish, reporting limits, and QAQC performance for each dataset. 8.3 Q UALITY A SSURANCE & Q UALITY C ONTROL (“QAQC”) P ROGRAMS Quality Control (QC) measures are typically set in place to ensure the reliability and trustworthiness of exploration data. Appropriate documentation of quality control measures and regular analysis of quality control data are essential as a safeguard for project data and form the basis for the Quality Assurance (QA) program implemented during exploration. Analytical QC measures typically involve internal and external laboratory procedures implemented to monitor the precision and accuracy of the sample preparation and assay data. They are also important to identify potential sample sequencing errors and to monitor for contamination of samples. Sampling and analytical QA/QC protocols typically involve taking duplicate samples and inserting quality control samples (CRMs and blanks) to monitor the reliability of the assay results throughout the drill program. Umpire check assays are typically performed to evaluate the primary lab for bias and involve re-assaying a set proportion of sample rejects and pulps at a secondary umpire laboratory 8.3.1 Historical QAQC The following section summarizes the historical sampling methodologies, analytical procedures, and quality assurance and quality control (QAQC) programs applied to the Elk Creek Project from the original Molycorp drilling campaigns (1973– 1986) through to NioCorp's 2021 re-sampling program. Detailed descriptions of all procedures, QAQC results, and the Qualified Person's (QP's) opinion are provided for in the 2022, S-K 1300 Elk Creek Technical Report Summary. Sampling at the Elk Creek Project spans five decades and multiple operators. Table 8‐2 summarizes the key attributes of each program era, including core size, laboratory, analytical methods, and QA/QC controls employed Table 8‐2: Summary of Historical Sample Preparation, Analysis, and QA/QC Programs — Elk Creek Project Program Era Period Core Size Laboratory Primary Analytical MethodsQA/QC Controls Employed Molycorp (Historical) 1973–1986 NQ / BQ Molycorp Louviers Lab (CO); occasional Bondar-Clegg WD-XRF on pressed powder pellets (pulverized to -325 mesh); Nb₂O₅ and LnO (total lanthanides) reported; individual REEs not reported Internal Elk Creek standards; instrumentation changed (Philips PW1212 → PW1400, 1981); limited external checks
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 55 | Page Program Era Period Core Size Laboratory Primary Analytical MethodsQA/QC Controls Employed Quantum / NioCorp Re- Sampling 2010 NQ / HQ pulps ALS Chemex, Reno NV (prep); ALS North Vancouver BC (analysis) XRF (ME-XRF10): pulverized to 90% passing -70 μm, Li- borate flux fusion; Nb₂O₅ reported; Sc and TiO₂ not included SRM SX18-01 & SX18-05 (Dillinger Hütte); field pulp duplicates; quartz blanks; subset checked at Hazen (Golden, CO) NioCorp Drilling (2011 Program) 2011 HQ core (half) Actlabs, Ancaster, ON (primary); Inspectorate (external check) XRF (Panalytical Axios-mAX, Li-metaborate/ tetraborate fusion, 2 g): Nb₂O₅ and Ta₂O₅. ICP/MS (Perkin Elmer Sciex, Li-borate fusion): 43 major/trace elements including REEs. Preparation: crush 90% <2 mm, riffle split 250 g, pulverize 95% <75 μm (Actlabs RX1) SRM SX18-01, SX18-04, SX18- 05 (Dillinger Hütte); CRM AMIS0185; field quartz blanks (5%); 1/4-core field duplicates (5%); coarse-reject and pulp duplicates; Inspectorate external pulp check (~5%) NioCorp Drilling (2014 Program) 2014 HQ / PQ core (half / quarter) Actlabs, Ancaster, ON (primary); SGS Lakefield, ON (secondary check) Same as 2011 program. Additional fluoride analysis (4F- F method) for NEC14- 006/007/008. SGS secondary: XRF (GO_XRF76V) for Nb₂O₅ and 13 major oxides; Sc by GE_JCP90A (ICP-MS, 5 ppm DL) SRM SX18-01, -02, -04, -05; field quartz blanks (5%); 1/4-core duplicates (~4.3%); coarse-reject duplicates (~2.7%); pulp duplicates (~4.9%); SGS external check pulps (~5%) Re-Sampling: Sc Infill 2014–2015 Molycorp pulps / coarse splits SGS Lakefield, ON Sc analysis only (GE_JCP90A); 1,410 samples from 2010 ALS program lacking Sc values CRM GRE-04 (Geostats; Nb₂O₅, Sc, TiO₂, REE); pulp duplicates (0.6%); insertion rate ~4.8% CRM Re-Sampling: Multi-Element Infill 2016 Molycorp pulps / fine crush Actlabs, Ancaster, ONFull multi-element ICP/MS and XRF (Code 8-Nb₂O₅, WRA4B2); 667 samples targeting missing TiO₂, Sc, and REE results from 2015 MRE CRM GRE-03 and GRE-04 (Geostats); SRM SX18-01; pulp duplicates (6.6%); insertion rate ~6.2% total standards Re-Sampling: REE / Sc Infill 2021 Molycorp pulps / coarse / chip splits Actlabs, Ancaster, ONFull multi-element ICP/MS and XRF (same as 2011/2014 programs); 1,094 interval samples targeting REE and Sc gaps in outer resource CRM GRE-03 (Geostats), Oreas 460 and 464, AMIS0185; insertion rate ~7% total control samples
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 56 | Page Program Era Period Core Size Laboratory Primary Analytical MethodsQA/QC Controls Employed boundaries across 19 historical drillholes Source: DGC 2022 8.3.1.1 Molycorp, 1973-1986 Detailed documentation of Molycorp's sampling procedures was not formally preserved, and the QPs did not directly review primary source records. Based on a review of previous technical reports and discussions with a former Molycorp sampling technician, the following procedures were reconstructed: • Drill core was photographed at the time of drilling. • Samples were derived from 5 ft (1.52 m) or 10 ft (3.05 m) intervals of hydraulically split, predominantly NQ diameter core, with minor BQ diameter material. Core was crushed on site prior to dispatch. • The on-site crusher was cleaned between samples using limestone blank material. • Core samples were shipped to Molycorp's exploration laboratory at Louviers, Colorado, for niobium (Nb₂O₅) and total lanthanide oxide (LnO) analysis by wavelength-dispersive XRF on pressed powder pellets, following pulverization to -325 mesh. Individual REE values were not reported. • Molycorp employed internal Elk Creek samples as standards. Over the project duration, the number and identification of these standards changed several times. In 1981, the primary instrument was upgraded from a Philips PW1212 to a PW1400. A limited number of samples from holes EC-27 and EC-30 were checked against an external commercial laboratory (possibly Bondar-Clegg), which used a single standard from hole EC-11 compared to 19 standards used by Louviers. • Sample homogenization methods were not clearly defined in historical records, and photographs of core were not included with available historic records. Historical drill core, coarse-reject splits, and pulverized material were donated to and are currently stored at a facility managed by the University of Nebraska-Lincoln (UNL), located approximately 5.2 mi (8.5 km) south of Mead, Nebraska. NioCorp and DGC have completed multiple site visits to confirm the condition and organization of stored material. The facility is secured and maintained by UNL. Select Molycorp samples were subsequently re-assayed in 2010, 2014, 2016, and 2021 to expand the analytical suite and apply modern QA/QC protocols. 8.3.1.2 NioCorp, 2011-2014 Re-sampling programs of historical Molycorp core and pulps were conducted between 2010 and 2014 to verify results and QA/QC procedures. In 2015 a re-assay program was conducted on pulps to add scandium and titanium analysis. Further re- sampling was conducted between 2016 and 2021. NioCorp implemented a detailed core processing and sampling program commencing with the 2011 drilling program, with continuous improvements applied through the 2014 program. Diamond drilling utilized HQ core as the standard size, with minor PQ intervals. Core was boxed at the drill site daily and transported to the on-site processing facility, where it was photographed, logged, and split.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 57 | Page Professional oversight was provided by geologists and engineers from DGC, SRK Consulting, and NioCorp. Core logging used standardized codes entered the Datamine Fusion drillhole database. The full carbonatite intersection was sampled at approximately 3.28 ft (1 m) intervals. Core was halved using electric, water-cooled diamond-bladed core saws (BD 3003E). Sampled intervals were placed in barcoded sample bags, secured in five-gallon plastic pails, and shipped via bonded trucking company to Activation Laboratories Ltd. (Actlabs), Ancaster, Ontario. Redundant barcode identification was applied both inside and outside each sample bag to ensure accurate chain of custody. Half-core not used for analysis was retained in labelled core boxes at the secured on-site facility. At Actlabs, samples were prepared using the RX1 modified preparation package: dried at 140°F (60°C) for 12 hours; crushed by jaw crusher to 90% passing 2 mm (with quartz wash between samples); riffle split to 250 g; and pulverized using ring and puck ESSA pulverizers to 95% passing 75 μm (with quartz wash between each sample). Primary analysis was by XRF (Panalytical Axios-mAX, Li-metaborate/tetraborate fusion, 2 g aliquot) for Nb₂O₅ and Ta₂O₅, and by ICP/MS (Perkin Elmer Sciex, Li-borate fusion) for 43 major and trace elements including the full REE suite. Actlabs maintained ISO/IEC 17025 and ISO 9001 accreditation throughout the program periods. SGS Lakefield, Ontario (ISO 17025 accredited) served as the secondary umpire laboratory for the 2014 program. SGS analyzed pulp splits for Nb₂O₅ and 13 major oxides by XRF (GO_XRF76V borate fusion) and Sc by ICP-MS (GE_JCP90A, 5 ppm detection limit). Fluoride analysis (method 4F-F) was additionally completed for holes NEC14-006, NEC14-007, and NEC14-008. 8.3.1.3 Historical Re-Sampling Programs, 2010-2021 NioCorp in 2010 and 2021, undertook four re-sampling programs targeting the historical Molycorp sample archive to expand analyte coverage, infill QA/QC data, and address gaps identified during successive resource estimates. 2010 Re-Sampling (Quantum/NioCorp): A total of 1,860 pulverized or coarse-split samples from Molycorp drillholes were submitted to ALS Chemex (preparation in Reno, NV; analysis in North Vancouver, BC) using method ME-XRF10 (Li-borate flux, XRF). Samples were selected based on geological interpretation and proximity to elevated Nb₂O₅ values. The program introduced NioCorp's first systematic QA/QC protocol over historical material, including SRM SX18-01 and SX18-05 (Dillinger Hütte), quartz blanks, and field pulp duplicates. A subset of results was checked at Hazen Research, Golden, Colorado. Note: Nordmin (2019) identified that SRM results ran consistently low using the ME-XRF10 methodology relative to later programs; this methodology was not used in the 2011 or 2014 drilling programs. 2014–2015 Sc Infill Re-Sampling: The 2015 Mineral Resource Estimate (SRK) identified that the 2010 ALS program did not include Sc analysis and that a portion of the database lacked TiO₂ and Sc values. A total of 1,410 pulverized Molycorp samples were submitted to SGS Lakefield for Sc-only analysis (GE_JCP90A), with CRM GRE-04 (Geostats; Nb₂O₅, Sc, TiO₂, REE certified) inserted at approximately 4.8%. 2016 Multi-Element Infill Re-Sampling: A second infill phase submitted 667 pulverized and fine-crush Molycorp samples to Actlabs for full multi-element analysis (Code 8-Nb₂O₅ XRF and WRA4B2 ICP/MS), targeting residual TiO₂, Sc, and REE gaps from the 2015 MRE. QA/QC included CRM GRE-03 and GRE-04 (Geostats), SRM SX18-01, and pulp duplicates at 6.6% insertion rate.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 58 | Page 2021 REE and Sc Infill Re-Sampling: An internal evaluation identified 1,095 intervals across 19 historical Molycorp drillholes that contained Nb₂O₅ results but lacked REE and Sc values within the outer resource boundaries. A total of 1,094 interval samples (1,047 pulverized splits, 24 coarse splits, and 23 chip splits) were submitted to Actlabs using the same ICP/MS and XRF methods applied in the 2011 and 2014 programs. QA/QC included CRMs GRE-03 (Geostats), Oreas 460 and 464, and AMIS0185, at a combined insertion rate of approximately 7%. 8.3.1.4 Quality Assurance and Quality Control NioCorp integrated a systematic QA/QC program across all 2011–2021 programs. Control sample types inserted at the field stage included: optical-quality quartz blanks (5%), CRMs and SRMs (5–6%), and field quarter-core duplicates (5%). These were supplemented by laboratory-generated coarse-reject and pulp duplicates, and external umpire laboratory check analysis. Table 8‐3 summarizes blank performance across the 2011 and 2014 drill programs. Table 8‐3: Summary of Field Quartz Blank Performance — 2011 and 2014 Drill Programs (Nb₂O₅) Drill Program No. of Blanks Submitted Insertion Rate Blank Failure Rate (Nb₂O₅) 2011 90 5.1% 39% (early program; corrected) 2014 454 4.7% 4% (following corrective measures) Source: DGC 2022 Note: (1) Failure defined as result exceeding 2× XRF detection limit. The elevated blank failure rate observed in the 2011 program (39%) was attributed to contamination early in the program. This was identified, reported to the laboratory, and corrective measures were implemented, resulting in a significant reduction to 4% failure in the 2014 program. Failing blanks were re-analyzed to differentiate between contamination and analytical error. The QPs concluded that blank material exhibited acceptable levels of error with no evidence of material contamination following corrective action. CRMs and SRMs used across the programs were sourced from carbonatite-matrix certified reference materials (Dillinger Hütte SX18-series; Geostats GRE-03 and GRE-04; Oreas 460 and 464; AMIS0185), all carrying certified values for Nb₂O₅, Sc, TiO₂, and REE as appropriate to the program era. Where SRM or CRM failures were identified, ten samples on either side of the failing control were re-assayed, with the re-assay result accepted as the final value. For the 2011 program, no standards required re-assay at a level of concern. Reject and pulp duplicate programs confirmed acceptable sampling precision throughout both drill programs, with most duplicate pairs plotting within expected variability ranges for the deposit type. Third-party external check analysis submitted to Inspectorate (2011) and SGS Lakefield (2014) confirmed the primary laboratory results were free from systematic bias. 8.3.2 NioCorp 2025 QAQC Routine QAQC procedures throughout the sampling and analytical analysis for the 2025 drilling programs continued at the highest level of quality standard throughout the process. Insertion of duplicate samples taken from various stages of the process, insertion of known control samples
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 59 | Page (SRMs, CRMs and blanks) and sending third-party pulps to the secondary lab was done similarly to previous sampling programs. Table 8‐4: Summary of designed level of insertion of QC submissions in the 2025 drill program. Sample Type Sample Sub-type Type Number Actual Insertion Rate Blanks Field Quartz Blanks Optical Quartz 463 6% Certified Reference Material OREAS 465 Nb CRM 116 6%OREAS 464 Nb CRM 95 GRE-11 Nb CRM 123 GRE-08 Nb CRM 120 Duplicates Field quartered core ¼ HQ Core 398 6% External Lab Checks Coarse-Rejects Reject split 282 4% Pulp Pulp split 490 6% Source: DGC 2026 To meet the planned QAQC insertion rates the following guidelines were followed: • Field quartz blanks (1 in 20, or 5%) were inserted within or immediately after samples collected from mineralized intervals, targeting zones of elevated visual mineralization, where possible. • CRMs (1 in 20, or 5%) were inserted in the field with the sample sequence. • Field quarter-core duplicates (1 in 20, or 5%) were inserted to test mineralization and sampling variability. The following sections provide detail on the types of samples used to validate the QA/QC results and the certain discussion around how the results were managed. 8.3.2.1 Field Quartz Blanks The 2025 Drill program had a similar methodology utilizing coarse natural clear quartz blanks (sourced from an optical- quality quartz quarry, in Arkansas, USA) whereby the samples were inserted into the sample sequence to identify potential contamination and to confirm sample sequence consistency. Table 8‐5: Summary of 2025 Drill Program Field Blank Insertion Element NbO Drill Program # of Assays sent to Lab 7,198 # of Field Quartz Blanks Sent to Lab 462 Insertion Rate of Blanks 6% # of Blank Failure (2x XRF Detection Limit) 51 Percentage of Blank Failure Rate 11% Source: DGC 2026 The TiO2 data for the blank quartz material is more variable than the Nb2O5 data. Results for Sc were 99% below the control line of 2 x XRF detection limit of 5ppm. Overall good results were returned for Nb2O5 and Sc. 2 5
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 60 | Page DGC considers that the blank material has acceptable levels of error and there is limited evidence of any major contamination issues at the laboratory. The laboratory utilised internally supplied blank material at the sample preparatory stage. Source: DGC 2026 Figure 8‐4: Summary of Blank Control Charts for Nb2O5, Sc, TiO2 Submission SGS for the 2025 Drill Program
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 61 | Page Source: DGC 2026 Figure 8‐5: Summary of Blank Control Charts for Nd, Pr, Dy and Tb Submissions to SGS 8.3.2.2 Certified Reference Material Certified reference material was selected for the 2025 sampling program to monitor the accuracy of the analytical methods. Four CRMS were selected for the sampling program based on their representativity of the carbonatite matrix. The main purpose of the CRM insertion was to provided controls of Nb2O5, Sc and TiO2. The CRM selected were OREAS464 and OREAS 465 from Ore Research & Exploration and GRE-11 and GRE-08 from Geostats. These were added as the best representation the Sc, TiO2, REE’s and the Nb2O5 ranges for the orebody. Table 8‐6: Summary of the CRM used for the 2025 Program Analyte Unit CRM - Certified Values OREAS 465 OREAS 464 GRE-11 GRE-08 NbO % 0.67 0.272 0.875 0.148 Sc ppm 149 141 72 91 TiO % 10.52 3.26 - - La ppm 24100 12000 523 1467 Ce ppm 39500 15300 135 5099 Pr ppm 3772 2597 601 953 Nd ppm 11800 9940 3574 4433 Sm ppm 1361 1498 452 515 Eu ppm 286 324 82.7 108.8 Gd ppm 584 676 183 283 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 62 | Page Analyte Unit CRM - Certified Values OREAS 465 OREAS 464 GRE-11 GRE-08 Tb ppm 57 54 17.5 33.4 Dy ppm 217 178 67 143 Ho ppm 27.7 21.3 8.5 19.1 Er ppm 50 38.2 17.1 33.8 Tm ppm 4.52 3.56 1.9 3 Yb ppm 19 15.7 9.9 14.6 Lu ppm 1.72 1.69 1.2 1.8 Y ppm 524 449 179 448 Source: DGC 2026 8.3.2.2.1 Nb2O5 standards and Certified Reference Material The summary of the results for Nb2O5 analysis for each CRM is summarized below. The 2025 drill program performed well showing a very low failure rates, less than 2%. Bulk of the results returned were within the acceptable 3 Standard deviation limits. Very low Bias overall was reported. With GRE11- and GRE08 reporting -4% and 2% respectively. The OREAS 464 and OREAS465 reported very low at 1% and 0%. Table 8‐7: Summary of the Nb2O5 Results per CRM (SGS) Standard (NbO) Count Certified Value (%) STD DEV (%) Mean Assay (%)Range (%) Min (%) Max (%) N outside 3SD OREAS 465 113 0.67 0.043 0.6691 0.43 0.27 0.7 1 1% OREAS 464 94 0.2723 0.0115 0.2747 0.41 0.25 0.66 1 1% GRE-11 123 0.87 0.03 0.84 0.77 0.15 0.92 2 2% GRE-08 119 0.148 0.005 0.154 0.04 0.13 0.17 1 1% Source: DGC 2026 The failure on OREAS464 and OREAS465 was due to a mislabelling of the CRM when sampled. The mislabelling was corrected in the database, Figure 8‐6 shows results of the original data before the correction. The performance observed for the certified reference material and their coverage support accurate assay results received for the assay labs and the incorporation of these results in future work is recommended. 2 5
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 63 | Page Source: DGC 2026 Figure 8‐6: OREAS465 and OREAS464 Results for Nb2O5 8.3.2.2.2 Sc standards and Certified Reference Material The summary of the results for Sc analysis for each CRM is summarized below. The 2025 drill program showed erratic values for Sc on OREAS465. The lab was contacted and the results began to improve. Failure rates on OREAS464, GRE-11 and GRE-08 showing a failure rate below 9%. Bulk of the results returned were within the acceptable 3 Standard deviation limits. Table 8‐8: Summary of the Sc Results per CRM (SGS) Standard (Sc) Count Certified Value ppm) STD DEV ppm) Mean Assay ppm) Range (ppm) Min (ppm)Max (ppm) N outside 3SD OREAS 465 113 149 9.1 156.07 69 132 201 31 27% OREAS 464 94 141 5.8 139.9 40 123 163 8 9% GRE-11 123 72 5 66.47 33 59 92 1 1% GRE-08 889 91 6 83.12 17 76 93 0 0% Source: DGC 2026 Very low Bias overall was reported. With GRE11- and GRE08 reporting very low bias at -8% and -9% respectively. The OREAS 464 and OREAS465 reported a low bias at 5% and -1% respectively. Source: DGC 2026 Figure 8‐7: OREAS465 and OREAS464 Results for Sc
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 64 | Page 8.3.2.2.3 TiO2 standards and Certified Reference Material The summary of the results for TiO2 analysis for each CRM is summarized below. The 2025 drill program showed variability at the start of the program. Internal Lab issues were addressed with SGS and results started showing more consistency. Failure rates on OREAS464 and OREAS465 showed low failure rates of 1%. GRE-08 and GRE-11 were not reported as the CRM did not have an approved methodology for reporting of the TiO2 analyte. Overall results returned were within the acceptable 3 Standard deviation limits. Table 8‐9: Summary of the TiO2 Results per CRM (SGS) Standard (Ti0) Count Certified Value (%) STD DEV (%) Mean Assay (%)Range (%) Min (%) Max (%) N outside 3SD OREAS 465 113 10.51 0.307 10.36 7.33 3.27 10.6 1 1% OREAS 464 94 3.26 0.099 3.32 7.4 3.043 10.53 1 1% GRE-11 123 - - 0.632 0.25 0.46 0.71 not measured GRE-08 119 - - 0.458 0.04 0.43 0.48 not measured Source: DGC 2026 OREAS465 and OREAS 464 reported -1 and 2% bias respectively. Differences after correction at the lab were negligible. Source: DGC 2026 Figure 8‐8: OREAS465 and OREAS464 Results for TiO2 8.3.2.2.4 Certified Reference Material and other REE results. The CRM’s used for the 2025 Drill programs provide reference control of Nd, Pr, Dy and Tb. These CRMs performed within acceptable ranges with a low bias across all grade ranges for both Nd and Pr. Reported results for both Dy and Tb were generally close to the expected values. There is a 1% to 8% percent sample failure rate for Nd, Dy and Tb. Pr showed a good performance on OREAS464 and OREAS465 with bias less than 1%, however on GRE08 and GRE11 result reported a positive bias between 3% to 9% resulting from several of the results falling outside the upper limits. These certified reference materials are not individually suited for REE evaluations but when considered in combination, the overall performance of REE’s across the 4 CRMS submitted to the lab is within acceptable limits. The results represent the expected levels of REE. 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 65 | Page Overall, the CRM’s performed well. Using this information obtained from external carbonatite projects assisted with compiling a better understanding of what is to be expected. Table 8‐10: REE performance on CRM's OREAS 465, ORES463, GRE-11 and GRE-08 OREAS 465 Element Count Certified Assay Value (ppm) STD DEV (ppm) Mean Assay (ppm) Range (ppm) Min (ppm) Max (ppm) N outside 3 STD DEV Nd 113 11800 500 11596 2907 9693 12600 1 1.00% Pr 113 3772 18.13 3781 1400 2800 4200 1 1.00% Dy 113 217 13 59 28.17 48.05 76.22 5 4.00% Tb 113 57 3.1 226 101 180 281 9 8.00% OREAS 464 Element Count Certified Assay Value (ppm) STD DEV (ppm) Mean Assay (ppm) Range (ppm) Min (ppm) Max (ppm) N outside 3 STD DEV Nd 94 9940 320 9828.6 2286 9114 11400 5 5.00% Pr 94 2597 106 2625.1 2900 1000 3900 5 5.00% Dy 94 178 8 184.89 51 171 222 5 5.00% Tb 94 54 2.7 54.8 14.37 49.1 63.47 4 4.00% GRE-11 Element Count Certified Assay Value (ppm) STD DEV (ppm) Mean Assay (ppm) Range (ppm) Min (ppm) Max (ppm) N outside 3 STD DEV Nd 123 3574 153 3514.1 1482 2926 4408 4 3.00% Pr 123 601 22 637 475 525 1000 19 15.00% Dy 123 67 2 67.6 89.07 56.93 146 8 7.00% Tb 123 17.5 0.9 17.07 17.38 14.61 31.99 3 2.00% GRE-08 Element Count Certified Assay Value (ppm) STD DEV (ppm) Mean Assay (ppm) Range (ppm) Min (ppm) Max (ppm) N outside 3 STD DEV Nd 119 4433 197 4361.3 734 3996 4730 0 0.00% Pr 119 953 36 982.7 600 700 1300 20 17.00% Dy 119 143 6 144.64 26 132 158 0 0.00% Tb 119 33.4 1.6 32.89 6.65 28.98 35.63 0 0.00% Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 66 | Page 8.3.2.3 Duplicates Pulp Duplicates The Pulp duplicates that were taken after pulverization, were sent to the lab as part of the 2025 sample submission. The 463 pairs represent approximately ~6% of total sample submissions from the 2025 drilling program. The results indicate a reasonable comparison between the original and duplicate assays (Figure 8‐9 and Figure 8‐10). All REE’s were evaluated, charted, and classified as reasonable comparisons, during this review and the targeted REE’s element charts. Source: DGC 2026 Figure 8‐9: Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Pulp Duplicate) Core Duplicate Analysis for Analytes Nb2O5 and Sc
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 67 | Page Source: DGC 2026 Figure 8‐10:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Pulp Duplicate) Core Duplicate Analysis for Analytes TiO2, Nd, Pr, Dy and Tb Course Reject Duplicates
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 68 | Page A total of 282 coarse duplicate samples, taken after crushing, were sent to the lab for analysis (blind) as part of the sample submission. This represent ~3% of the total sample submissions from the 2025 drilling program. Upon review there was a positive mean difference trend for TiO2, Tb, Pr, Dy where Nb2O5, Sc showed a negative mean bias. Overall, the precision of the results is within the acceptable limits as no analyte fell beyond the 10% average relative difference boundary (Figure 8‐11 to Figure 8‐13). Source: DGC 2026 Figure 8‐11:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nb2O5, Sc and TiO2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 69 | Page Source: DGC 2026 Figure 8‐12:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nd and Pr.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 70 | Page Source: DGC 2026 Figure 8‐13:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Dy and Tb. Field ¼ Core Duplicates A total of 398 field duplicate samples comprised of ¼ core were resubmitted to the lab representing 5.5% of total sample submissions for 2025. The results for the ¼ core duplicates were relatively good. A small positive bias was reported for TiO2, Nd, Pr, Dy and TiO2 and a slight negative bias on Nb2O5 and Sc less than 1%. Overall excellent precision reported for the samples retuned for the 2025 exploration program (Figure 8‐14 to Figure 8‐16).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 71 | Page Source: DGC 2026 Figure 8‐14:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nb2O5, Sc and TiO2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 72 | Page Source: DGC 2026 Figure 8‐15:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Nd and Pr
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 73 | Page Source: DGC 2026 Figure 8‐16:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (Coarse Reject Duplicate) Core Duplicate Analysis for Analytes Dy and Tb 8.3.2.4 Third Party Check Samples For 2025, pulp duplicates of the samples that SGS labs prepared samples were submitted to Actlabs for alternative analyses. These 463 pulps represent approximately ~6% of total sample submissions from the 2025 drilling program. An additional 27 of those external duplicated were duplicated and sent to an umpire lab for testing. Overall, 490 external pulps were analysed to determine if there is any bias. There is a slightly high bias observed from these results. A possible reason for these results could be that most duplicate samples are expected to a have a degree of variability between laboratories and analytical methods. • It is recommended to utilise a higher relative difference cutoff be considered when comparing third party duplicate check analysis. The Samples for both analyses reviewed remain below an average 10% relative difference, identifying a degree of risk, but falling within accepted limits.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 74 | Page Source: DGC 2026 Figure 8‐17:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Nb2O5, Sc and TiO2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 75 | Page Source: DGC 2026 Figure 8‐18:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Nd and Pr
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 76 | Page Source: DGC 2026 Figure 8‐19:Paired Relative Difference and an XY Scatter Comparison of Original Versus Quarter (External Lab Duplicate) Core Duplicate Analysis for Analytes Dy and Tb. 8.4 Q UALIFIED P ERSON ’ S O PINION ON THE A DEQUACY OF S AMPLE P REPARATION , S ECURITY & P ROCEDURES It is the QP’s opinion that the sample preparation, security, and analytical procedures used by NioCorp are consistent with standard industry practices and that the data is suitable for the 2026 Mineral Resource Estimate. The continuation of a robust QAQC program from the 2022 work has led to the opinion that there are no material concerns with the geological or analytical procedures used or the quality of the resulting data. The QP confirms that the Elk Creek geological database is of suitable quality to support both Mineral Resource and Mineral Reserve estimation. The QPs responsible for the preparation of this report have reviewed the historical sample preparation, analytical procedures, and QA/QC protocols and have confirmed they remain current and applicable to the geological database used in this report. No new material scientific or technical information has become available that would alter the QP's opinion on the adequacy of the historical data.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 77 | Page 9 D ATA V ERIFICATION The QPs responsible for this report have reviewed the data verification section of the 2022 Technical Report Summary and are satisfied that the procedures described therein are adequate for the purposes of this report. The QPs confirm that the geological database is of suitable quality to support the Mineral Resource and Mineral Reserve estimates disclosed herein. 9.1 D ATA V ALIDATION Site visits to the Elk Creek Project between 2025 and 2026 are detailed below in Table 9‐1: Table 9‐1: Summary of QP Site Visits QP Company Expertise Date(s) of Visit Jacob Anderson, CPG, MAusIMM Dahrouge Geological Consulting USA Ltd. Mineral Resources September 8 to 10, 2025 Janine Brown, P.Geo. Dahrouge Geological Consulting USA Ltd. Geology May 10 to 16, 2025 Trevor Mills Dahrouge Geological Consulting USA Ltd. Geology; procedures; QAQCMultiple times from April 24, 2025 to November 17, 2025 Amélie C. Ouellet, P.Eng Andrieux & Associates Geomechanics Consulting Rock Mechanics May 13-14 2025 Scott Britton, P.E. Amplify Mine PlanningReserves/Mining March 30 to 31, 2026 Adrian Brown, P.E. Adrian Brown Consultants Inc Hydrogeology July 25 to August 12, 2025; September 23 to September 25, 2025 Troy Meyer, P.E. P.Eng Tierra Group/BBA Tailings January 22, 2026 Anthony (Tony) Linton, FEC, P.Eng., IntPE (Canada) Dumas Contracting USA Inc. Mine Engineering March 10 to 11, 2026 Eric Larochelle, B.Eng SMH Process InnovationHydrometallurgy & Process Engineering March 12, 2026 During the site visits completed by the Qualified Persons, the following site visit included: • Review of current drilling, logging, sampling, analytical and QAQC procedures used during the 2025 drilling program. • Review and verification of the interpreted geological setting of the Project. • Visual confirmation of some previously completed drill hole collars.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 78 | Page • Visual confirmation of previously completed drilling in 2011 and 2014. • Review of overall site facilities. 9.1.1 Core Processing Protocols Core processing was completed by DGC during the 2011 and later work programs. As such, the QPs have relied on DGC’s database to review the core logging procedures, collection of samples, and chain of custody associated with those programs. DGC provided the QPs with data exports from the project drillhole database (MX Deposit) and electronic copies of the original assay certificates and procedural documentation. The QA/QC protocols employed by DGC included the routine insertion of field duplicates, laboratory pulp duplicates, blanks, and niobium, scandium, titanium and REE certified reference standards. No significant issues were identified during the site visit. It is DGC’s opinion that the geological data collection procedures and the chain of custody were found to be consistent with industry standards and in accordance with NioCorp’s internal procedural documentation. 9.1.2 Database Validation Multiple database validations have been completed by SRK between 2014 and 2017, with subsequent validations completed by Nordmin in 2019, Understood and Optimize in 2022. Detailed information on database validations is described in detail in previous technical reports on the Project. Data validation for the current report is summarized below. Validation consisted of the verification of collar locations, downhole survey data, geologic and assay data, along with checks for missing values, duplicate entries and inconsistencies among tables. Checks were applied to confirm that the aforementioned data types were accurate and fell within the appropriate thresholds. All inaccuracies that were identified were corrected before incorporating them into the final dataset. 9.1.3 NioCorp QAQC It is the opinion of the QPs that NioCorp implemented a robust QA/QC process, as described in Section 11. Assay results were actively monitored throughout all drill programs including the 2025 drill program and QA/QC results were summarized. A number of failures for standard and blank reference materials were documented. Most of the reference materials performed as expected within tolerances of 2 to 3 standard deviations of the mean grade. The QP is satisfied that the QA/QC process is performing as designed to ensure the quality of the assay data. 9.2 L IMITATIONS All Qualified Persons were not limited in access to any of the supporting data use for the resource estimation or describing the geology and mineralization in this report. The database verification is limited to the procedures described above. All mineral resource data relies on industry professionalism and integrity of those who collected and handled the database. 9.3 Q UALIFIED P ERSON ’ S O PINION It is of the opinion of the QP that all geological data collection, standard operating procedures and QA/QC procedures implemented during all programs since 2011 are of suitable quality to support the Mineral Resource and Mineral Reserve Estimates and meet industry best practice standards.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 80 | Page 10 M INERAL P ROCESSING AND M ETALLURGICAL T ESTING This section describes the mineral processing and metallurgical testing conducted for the Elk Creek Niobium, Scandium, Titanium, and Rare Earth Production Facility. The Qualified Persons (QPs) for this section have reviewed the testwork and modeling results and opine that they provide a reasonable basis for the process flowsheet, subject to the limitations noted. The process targets production of niobium, scandium, titanium tetrachloride (TiCl4), and rare earth products from the Elk Creek orebody. It is the QP’s opinion that the data generated from the testwork is adequate for the purposes of this TRS, and that the data itself was produced using conventional industry practice. The metallurgical program for the Elk Creek Project has evolved through multiple phases, incorporating drill core analysis, mineralogical reconciliation, bench-scale tests, pilot campaigns, and demonstration plant operations. Recoveries and performance metrics presented in this section are derived from empirical data as observed by L3 Process Development during various bench scale and demonstration scale testing campaigns. L3 is independent of the Company and is not certified by any standards association. The QP (SMH) provided oversight for all of the metallurgical work conducted at L3’s facilities in Trois Rivieres, Quebec. 10.1 H ISTORICAL T EST W ORK Historical metallurgical test work was conducted at SGS Canada Inc. (SGS), Hazen Research (Hazen) and Kingston Process Metallurgy (KPM) throughout 2014, 2015, 2016 and into 2017 to properly design the required process units for the conversion of mined ore into niobium, titanium and scandium products. The preliminary test work was performed on flotation concentrate, which has since been abandoned due to the poor recovery it offered. Test work then focused on whole ore as a feed and consisted of the extensive exploratory bench and pilot scale hydrometallurgical test programs aimed at defining and proving out a flowsheet using different reagents and technologies. The historical process flowsheet was therefore established and proven by test work and piloting performed in all the process units. Historical metallurgical test work has been previously extensively disclosed in technical reports issued during the period 2015-2022. Table 10‐1: Summary of Historical Technical Reports Technical Report Stage Issue Date Source Preliminary Economic Assessment 2015-05-15 (SRK, 2015) Feasibility Study 2017-08-10 (SRK, 2017) Feasibility Study 2019-05-29 (Nordmin, 2019) Feasibility Study 2022-06-28 (Batty et al., 2022) 10.2 M INERAL P ROCESSING The comminution test work was completed in two stages at SGS Canada Inc. (SGS) in Lakefield, Ontario in 2016. The primary stage test work (SGS 2016a) was conducted on six composite samples and 13 variability samples and included: • Bond Rod Mill Work Index (Rwi) testing. • Bond Ball Mill Work Index (Bwi) testing. • Bond Abrasion Index (Ai) testing.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 81 | Page • Bond Low-energy Impact (Cwi) testing. • JK Drop Weight (JKDW) testing. • Semi-autogenous grinding (SAG) Mill Comminution (SMC) testing. The second stage of comminution test work (SGS 2016b) was conducted on a single composite sample, using a LABWAL high-pressure grinding roll (HPGR) semi-pilot scale test work program. The test work results indicate that the Project ore is categorized as soft to moderately hard in terms of ore hardness, and amenable to standard grinding as well as an HPGR operation. A bulk representative sample (approximately 3,000 kg) of ore was subjected to locked cycle pilot scale testing at NRRI- Coleraine in Minnesota. The ore tested indicates that it is amenable to processing via the HPGR. Autogenous layer buildup and flake generation were both acceptable, and there was, on average, 40% < 1 mm product generated from the HPGR when in steady state. The most notable observations from the testing are: a) Final product particle size is largely independent of press force and moisture b) Specific energy increases as both moisture and press force increase c) There is a decrease in specific throughput as the press force increases d) There is a decrease in specific throughput as the feed moisture increases Based on the results as indicated above, it would be recommended to run an installed HPGR at lower pressures, i.e. 3.0 N/mm2 or less, and to remove as much free water from the circuit as possible. This will have the effect of reducing power requirements with limited to no impacts on size reduction. The data as collected to date is suitable for full HPGR scale up and process guarantees around envisioned plant operation conditions. 10.3 H YDROMETALLURGY 10.3.1 Mineralogy and Feed Characterization The following ore samples were received by L3 Process Development and used in the execution of bench scale, pilot scale and demonstration scale underlying the flowsheet disclosed in this technical report. The material was characterized as screen undersized material from the High-Pressure Grinding Rolls (HPGR) test work performed by Weir. The ore used in the HPGR test was obtained from assay reject samples from exploration activity, all passing 10 mesh. These samples were received from the 2014 core drilling program and were used as feed material to test the HPGR circuit. A total of ten representative samples representing different areas of the mine that could be reasonably expected during production were combined into a composite sample and used as feed to the HPGR program. The material received at the demonstration plant was analyzed, and the results are shown in Table 10‐2.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 82 | Page Table 10‐2: Ore Feed Characterization Summary Parameter Value/Source Key Minerals Carbonates (converted to oxides), MgO, CaO, REE-bearing phases Elemental Content Reconciled from drill core assays Water Content Estimated from anhydrous/hydroxide minerals Mass Loss (Calcination) ~30% (CO2 + H2O) 10.3.2 Process Development & Flowsheet The process flowsheet follows a sequential structure divided into areas and units. The area breakdown is as follows: Area 100 – Ore Activation Area 200 – Ammonium Chloride Cycle Area 300 – Hydrochloric Acid Leach Area 400 – Sulfuric Acid Baking and Water Leaching Area 500 – Niobium and Titanium Recovery Area 600 – Rare Earth Elements Extraction Area 700 – Rare Earth Separation Area 800 – Chloride Recovery Area 900 – Sulfate Effluent Treatment 10.3.2.1 Metallurgical Recoveries and Performance Table 10‐3 summarizes the product recoveries for each of the areas. Table 10‐3: Product Recoveries per area Element/Unit 100 / 200 300 400 500 600 700 Overall Ti 100% 99.00% 81.20% 100% 80.50% Nb 100% 99.70% 85.40% 99.60% 84.70% Sc 100% 96.20% 98.10% 94.30% Pr 100% 90.00% 100% 98.50% 88.70% Nd 100% 94.90% 100% 99.40% 94.40% Tb 100% 95.00% 100% 99.30% 94.40% Dy 100% 95.00% 100% 99.50% 94.60%
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 83 | Page 10.3.2.1.1 Area 100 – Ore Activation The activation process involves the thermal decomposition of carbonates minerals to oxides in an indirect natural gas rotary calciner at 1,454°F (790°C). During this process, CO2 is released then recovered, dehydrated and used to mineralize calcium and magnesium in Area 200 - Ammonium Chloride Cycle. Ore activation is performed using a continuous rotary kiln processing 10 kg per hour at an external tube temperature of 1,652°F (900°C) for an average of 15 minutes. In this process, calcium and magnesium carbonates are converted to their respective oxides and made available for leaching by an ammonium chloride solution. Approximately 21 wt% of the initial ore mass is lost during this stage. Between 2022 and 2023, L3 generated approximately 2,400 kg of calcined ore. As part of an on-going optimization campaign, L3 has processed an additional 1,153 kg since January 2026. 10.3.2.1.2 Area 200 - Ammonium Chloride Cycle The ammonium chloride cycle is a closed loop process using an ammonium chloride solution to selectively leach Ca and Mg as chlorides, followed by their mineralization as carbonates, regenerating the ammonium chloride leach solution. The demonstration unit has been operated during 11 months between 2022 and 2024 to process the 2,400 kg of calcined material. The continuous demonstration unit operation revealed that the leaching process was effective with over 80% calcium removal achieved. The complex equilibria between ammonia (a weak base) and carbonic acid (a weak acid) in combination with magnesium and calcium ions resulted in difficulty precipitating the MgCO3 from solution in initial design of the Carbonate Mineralization portion of the circuit. As a result, additional test work was performed to identify a steady-state process that would successfully mineralize MgCO3 from solution. During the 2026 Elk Creek Study, L3 modeled the system and the speciation across the unit. The difference in behavior between calcium and magnesium allowed for a 2-stage selective precipitation of both elements in sequence and for a potential increase in calcium recovery. Since 2025, L3 has performed various optimization campaigns to support the 2026 Elk Creek Study modeling and associated recovery of calcium. Selected experiments conditions and leach efficiencies are presented as Table 10‐4. Concentration of feed and residue in the NHL leach unit is presented in Figure 10‐1. Table 10‐4: Ammonium chloride test conditions and associated recoveries for select tests. Experiment ID NCPn NHL25 NCPn NHL28 NCPn NHL31 NCPn NHL33 Leaching Conditions Concurrent Concurrent Countercurrent Countercurrent Temperature (°C) (Leach 1/Leach 2) 99/99 99/99 98/98 99/100 NH4Cl Conc. (gpL) 125 125 125 125 Leach pH (1/2) 7.69/8.06 7.03/6.85 7.77/7.73 7.67/7.59 % Solids 10% 10% 10% 10% Reaction time (min) (Leach 1/Leach 2) 135/50 90/60 120/50 120/50 Leach Efficiency Ca 82% 68% 79% 80%
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 84 | Page Mg 40% 43% 73% 66% Fe 5% 2% 0% 0% LREE 0% 0% 0% 0% MREE 0% 0% 0% 0% HREE 0% 0% 0% 0% TREE + Y 0% 0% 0% 0% Source: L3 2026 Source: L3 2026 Figure 10‐1:Calcium (top) and Magnesium (bottom) concentration over time and moving average trendline. Recovery of selected concurrent and counter current campaigns are presented as Figure 10‐2. A detailed look at the countercurrent leach recoveries is presented as Figure 10‐3. The demonstration
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 85 | Page unit was modified in March 2026 to reflect the dual precipitation process, and initial data is presented in Figure 10‐4. Source: L3 2026 Figure 10‐2:Ammonium chloride leach performance for Ca and Mg. img170397038_40.jpg Source: L3 2026 Figure 10‐3:Ca and Mg leaching performance per countercurrent leach stage.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 86 | Page Source: L3 2026 Figure 10‐4:(a) Ca and Mg distribution in the precipitate from the Ca Precipitation (CaP) and the Magnesium Precipitation (MgP). (b) The aqueous concentration in grams per liter of Ca and Mg after the precipitation process. 10.3.2.1.3 Area 300 - Hydrochloric Leach The hydrochloric acid leach area employs a counter-current HCl leach circuit to solubilize metals and concentrate niobium and titanium in the residue. The following section is adapted from Larochelle et al., 2024: “A new paradigm for the recovery of rare earth elements: the high activity flowsheet as applied to the Elk Creek deposit” (Proceedings IMPC 2024: XXXI international mineral processing congress). The initial hydrochloric acid leach unit was composed of a cascade of three 1-hour residence time agitated reactors with temperature controlled at 80 ºC. L3 operated this unit for approximately 6 months, processing ammonium chloride circuit residue. During the demonstration campaign and following the optimization of the ammonium chloride operation, it became obvious that the HCl pregnant leach solution (HCl-PLS) had too much residual acid, with molarities up to 5 M HCl, for the subsequent solvent extraction circuits. Slurry handling equipment constraints between the reactor stages at the chosen scale prevented L3 from increasing the solids content in the leach circuit. Thus, it was decided that HCl-PLS would be recycled in the leach circuit to mimic a high solids content. L3 operated the hydrochloric acid leach circuit for approximately 5 months in its initial configuration and for three months in the configuration where recycled PLS was used on fresh solids to mimic the high-density leaching operation. The circuit processed approximately 1,500 kg of ammonium chloride leach residue. The leach efficiency and HCl-PLS composition for both scenarios is presented in Table 10‐6. The typical HCl-PLS composition for each scenario is presented as Table 10‐5. The low- density leaching operation aggregates data from approximately 1- month continuous campaign while the high-density operation aggregates data from over a month of HCl-PLS fed to the solvent extraction process covering many leach campaigns. XRF assays are identified using a * and are elements that do not have a significant impact in the solvent extraction circuit. The improved process allowed for smaller and more efficient solvent extraction circuits.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 87 | Page Table 10‐5: HCl-PLS composition of for high and low density scenarios. Low Density Leaching High Density Leaching Element Unit Average σ Average σ Mg mg/L 2,657 440 6,545 273 Ca mg/L 7,331 2,003 36,759 2,192 Si* mg/L 10 9 1.6 3.0 Al* mg/L 980 423 1,607 155 Fe mg/L 20,854 1,862 58,502 3,185 Mn* mg/L 840 163 1,485 98 Zn* mg/L 55 14 115.8 12.4 Ti mg/L 266 29 97.1 9.5 Nb mg/L 22.6 6 7.5 0.9 Sc mg/L 10.2 2.3 24.4 2.1 TREE mg/L 429 56 1,144 114 Th mg/L 45.5 6.9 160.7 9.6 Source: L3 2026 The PLS generated during those campaigns was used to operate the solvent extraction demonstration circuit described in Section 10.3.2.1.6. Following the initial campaign, L3 has modified the leaching unit to transition from a co-current unit toward a counter-current unit. Initial test work revealed this arrangement was more effective in leaching the rare earths and scandium. Selected experiments are presented in Table 10‐6. Table 10‐6: Test conditions and leach efficiencies for select HCl leaching tests. Experiment ID NCPl HCL03 NCPl HCL04 NCPm HCL12 NCPm HCL13 NCPn HCL15 NCPn HCL16 Leaching Conditions Temperature (°C) (Leach 1/Leach 2) 90/90 90/90 90/60 80/60 80/60 80/60 PLS Acid Molarity NA 1.88 4.56 7.04 3.03 2.65 Feed Iron Mass % 27.2% 18.0% 21.3% 20.4% 20.9% 19.3% % Solids 25% 25% 17% 17% 30% 30% Reaction time (min) 120 120 60 60 20 20 Leach Efficiency
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 88 | Page Experiment ID NCPl HCL03 NCPl HCL04 NCPm HCL12 NCPm HCL13 NCPn HCL15 NCPn HCL16 Ca 98% 97% 91% 90% 91% 89% Mg 99% 99% 97% 94% 99% 94% Fe 97% 97% 90% 86% 89% 82% Th 96% 73% 89% 93% 75% 67% Nb <1% <1% <1% <1% <1% <1% Ti <1% <1% <1% <1% <1% <1% Sc 98% 88% 96% 98% 89% 86% LREE 98% 89% 93% 92% 88% 84% MREE 98% 92% 95% 95% 90% 82% HREE 98% 87% 94% 93% 80% 59% TREE + Y 98% 89% 94% 93% 89% 82% Source: L3 2026 Two tests were performed using material optimally processed in the ammonium chloride circuit. The tests were performed using 4,500 g of ammonium chloride circuit residue and subjected to a counter current leach using 13 liters of PLS from the previous stage 2 experiment and 15 liters of 32 wt.% hydrochloric acid. Both leaches were performed at 194°F (90°C) for 120 minutes. The individual rare earth recoveries for these experiments are presented as Table 10‐3. Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 89 | Page Figure 10‐5:Leach efficiencies for leach 1 and leach 2 in the counter current leach process. 10.3.2.1.4 Area 400 – Sulfuric Acid The sulfuric acid area employs a pug mill, where concentrated sulfuric acid is mixed with the residue from the Hydrochloric Acid leach circuit, and a rotary calciner to convert niobium and titanium to water-soluble sulfates. This is then followed by their dissolution and hydrolysis. Selected experiments are presented Table 10‐7. Calculated recoveries of typical experiments are presented as Source: L3 2026 Figure 10‐6. However, it should be noted that the system is designed to account for the residual concentrations following the recycling of barren solution in the water leach and hydrolysis circuit. Therefore, such concentration profiles for selected representative experiments are presented as Figure 10‐7. Table 10‐7: Experiment test conditions and results for select acid bake-water leach tests. Experiment ID NCPm-ABK03 NCPm-ABK04 NCPn-ABK05 Acid Bake Conditions Outlet Temperature °C 300 300 300 Acid/Solid Ratio (m/m) 48% 49% 36% Cake Yield 132% 134% 81% Experiment ID NCPm-WTL09 NCPm-WTL10 NCPn-WTL10 Water Leach Conditions Temperature °C 90 90 40 Reaction Time (min) 120 120 30 % Solid 23% 23% 23% Wash Conditions Number of Washes 3 3 3 Final Cake Humidity 30% 34% 36% Conversion Efficiency Fe 72% 89% 65% Ti 86% 79% 80% Nb 89% 85% 91% Source: L3 2026 Table 10‐8: Experiment test conditions and results for select hydrolysis tests. Experiment ID NCPm-HYD07 NCPm-HYD08 NCPm-HYD12 NCPm-HYD15 Hydrolysis Conditions Temperature °C 105 105 105 105 Reaction Time (min) 30 30 30 30
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 90 | Page Water to PLS Ratio 2 2 2 2 Residual Concentration (g/L) Fe 0.52 0.75 0.30 0.22 Ti 0.28 0.73 0.24 0.16 Nb 0.06 0.23 0.50 0.01 Source: L3 2026 Source: L3 2026 Figure 10‐6: Ti and Nb water leaching efficiency of acid baked material over various tests. Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 91 | Page Figure 10‐7: Aqueous concentration in gram per liter throughout the hydrolysis procedure for Ti and Nb. (a) NCPn-16, (b) NCPn-17, (c) NCPn-18. 10.3.2.1.5 Area 500 – Chlorination Carbo-chlorination (Chlorination) is the primary commercial process to convert titanium oxide into titanium tetrachloride, which is then purified by distillation. It has also been applied successfully to other refractory metals. The reaction involving both carbon and chlorine is presented as Eq. MxOy + yC + yCl2 → xMCl2y/x + yCO Chlorination test work was performed in two phases of increasing complexity. The goals of the test work campaigns were to demonstrate that the chlorination and separation of Nb from Ti from hydrolysate material could be achieved. A minimum working chlorinator and condensing train was designed, fabricated, and operated. The phase I unit is illustrated as Figure 10‐8. . Source: L3 2026 Figure 10‐8:L3 2026 Phase I consisted of 5 experiments, involving the processing of 502g of hydrolysate material. While the technical feasibility of niobium chlorination was demonstrated, the design of the unit did not allow for the calculation of a mass balance. A summary of the test work parameters and results is presented as Table 10‐9 and Table 10‐10 respectively.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 92 | Page Table 10‐9: Phase I Experimental Conditions Test No Hydrolysate Mass Graphite Feed Ratio Temperature Cl2 Flow Retention Time g m/m °C CFH min 1 70 0.17 900 5 60 2 120 0.67 900 5 70 3 108 0.50 900 3 120 4 108 0.50 900 3 120 5 96 0.33 900 3 120 Source: L3 2026 Table 10‐10: Phase I Results Recovery Nb/Ti Ratio (wt.%) Test No Mass Out Nb Ti In C1 C2 C3 2 30.1 N/A N/A 0.31 9.32 12.69 0.03 3 N/A N/A N/A 0.43 3.31 0.35 0.06 4 28.49 96% 93% 0.43 17.45 10.44 0.03 5 8.26 99% 99% 0.36 10.09 28.01 0.04 Source: L3 2026 The first series of tests allowed the researchers to ensure the safe operation (test 1, not presented) and validate the operating procedures while starting the data collection. This first campaign demonstrated that chlorination was an effective method for recovering niobium and separating it from titanium. Recoveries are estimated from the chlorinator feed and residue and should be used as indicative only. Phase II involved the addition of a titanium tetrachloride scrubbing loop similar to the commercial flowsheet design. The goal of phase II was to demonstrate that niobium could be recovered and separated from titanium using selective condensation and titanium vaporization with an emphasis on the composition of the niobium product. Recoveries should also be considered as indicative because the campaign did not aim at their optimization. The phase II unit is presented as Figure 10‐9.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 93 | Page Source: L3 2026 Figure 10‐9:Phase II Chlorination Equipment Design Phase II consisted of 3 weeks of tests, involving the processing of 2,779 g of hydrolysate material. The technical feasibility of niobium separation and recovery from titanium was demonstrated with niobium samples with low titanium concentration. Summary of the test work is presented as Table 10‐11 and Table 10‐12. Table 10‐11: Phase II Experimental Conditions Week Hydrolysate Mass Graphite Ratio Temperature Cl2Flow Retention Time g C:H °C CFH min 1 820.8 0.21 900 3 60 2 1096.8 0.20 900 3 60 3 861.6 0.21 900 3 60 Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 94 | Page Table 10‐12: Phase II Results Nb/Ti Ratio Week Residue (g) In Out Nb 1 495 0.36 73.41 22.24 2 513 0.39 119.12 27.1 3 402 0.35 125.71 27.27 Source: L3 2026 10.3.2.1.6 Area 600 – Rare Earth Elements Extraction The Rare Earth Elements Extraction area uses dimethyloctyl dihexyl diglycolamide (DMODHDGA, DGA-6) to selectively extract rare earths and scandium from HCl PLS at high activity. Co-extracted impurities are then scrubbed and the rare earth are stripped using a weakly acidic chloride solution. Residual iron in the strip liquor is precipitated out as iron hydroxide using ammonium hydroxide and the REE-rich strip solution is sent to Area 700 – Rare Earth Separation. Bench scale extraction test work was performed on HCl PLS at different acidity and activity levels. Selected extraction experiments are described as Table 10‐13, with results presented as Table 10‐14. Each test was performed using a matrix approach to reproduce the effect of a 3-stage counter-current extraction circuit and derive distribution ratios from developed profiles using aqueous-based mass balance. The data presented is the 3rd stage extraction data. Table 10‐13: Extraction PLS Description Experiment ID (NCPt) DG6-01 Base Case HCl PLS DG6-02 DG6-01 PLS Neutralized to 2.11M HCl using MgCO3 DG6-03 DG6-01 PLS diluted to 1.5 M HCl using ROW DG6-04 DG6-01 PLS Neutralized to 1.0M HCl using MgCO3 Source: L3 2026 Table 10‐14: Experiment test conditions and results for select DGA-6 extraction tests Experiment ID (NCPt) DG6-01 DG6-02 DG6-03 DG6-04 Extraction parameters O:A 1:3 1:3 1:3 1:3 PLS Free Acid (M) 2.72 2.11 1.54 0.96 Contact Time (min) 30 30 30 30 Results Raff. Free Acid (M) 2.63 2.27 1.17 1.09 Disengagement (sec) 30 30 15 30 Phase Separation (min) 3.5 4.0 1.3 5.0
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 95 | Page Experiment ID (NCPt) DG6-01 DG6-02 DG6-03 DG6-04 Distribution Ratio* Mg 0.07 0.11 0.21 0 Ca 0.62 0.57 1.37 0.55 Al 0.03 0.11 0.47 0 Fe 1.53 1.07 1.49 1.25 Ti 1.31 0.82 0.62 0.28 Nb 1.04 2.08 ** 0.36 0 Sc 5.2 3.65 313 3.43 Y 4.03 3.10 11.61 3.53 La 4.24 3.08 4.91 3.31 Ce 5.95 4.25 22.99 4.36 Nd 7.46 5.33 73.71 5.88 Dy 3.86 7.61 37.05 5.23 Th 0.65 0.58 0.44 0.14 * Sc, Y and Dy had raffinate concentrations near the ICP-OES detection limit and should be considered indicative only. ** DL in organic phase assay. Source: L3 2026 Bench scale scrubbing test work was performed on loaded organic at different acidity and activity levels. Selected scrub experiments are described as Table 10‐15. Each test was performed using a matrix approach to reproduce the effect of a 3- stage counter-current scrub circuit. Table 10‐15: Experiment test conditions and results for select DGA-6 scrub tests Experiment ID (NCPt) DG6-01 SCB-01 DG6-01 SCB-02 DG6-08 DGB-07 Extraction parameters O:A 1:1 1:1 3:1 Scrub Solution Free Acid (M) 0.01 0.01 0 Scrub Solution MgCl2 (M) 0.5 0.1 1.2 Contact Time (min) 15 15 15 Scrub Stage No 3 3 1 Results SCB Liquor Free Acid (M) 0.53 0.45 0.37 Disengagement (sec) 15 15 60 Phase Separation (min) 2.0 2.0 5.0 Distribution Ratio
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 96 | Page Experiment ID (NCPt) DG6-01 SCB-01 DG6-01 SCB-02 DG6-08 DGB-07 Mg N/A N/A 0.07 Ca 2.73 1.12 1.05 Fe 0.66 0.35 1.81 Sc Note 1 2,724 553.9 Y 4,018 157 1,288 La 5.28 1.66 52.1 Ce 19.58 4.14 409.2 Nd Note 1 21.47 150.8 Dy Note 1 180.77 Note 1 Th Note 1 4.43 N/A Source: L3 2026 Note 1. UDL in the scrub liquor. 10.3.2.1.7 Area 700 - Rare Earth Separation L3 used its predictive rare earth separation simulation software and literature extraction data to design a separation flowsheet to recover magnet rare earth elements. The first circuit in the area was assembled and operated over a 3-month period using synthetic PLS with ratios similar to the modeled REE extraction circuit strip liquor to generate calibration data for more accurate circuit modeling. The circuit was designed with 2 saponification stages, 6 extraction stages, 16 scrub stages, 24 strip 1 stages, 6 strip 2 stages and 2 strip 3 stages. The organic phase was prepared using 35 v% Cyanex 572 diluted in D80 kerosene. The circuit operated as intended and a summary of the operation, with the circuit concentration of target element across the various discharge streams is presented as Figure 10‐10 to Figure 10‐13. The relative distribution of each element across those streams is then presented as Figure 10‐14 to Figure 10‐17. The operation parameters are presented as Table 10‐16. Table 10‐16: REE solvent extraction operational parameters. SAP EXT SCB STR1 STR2 STR3 Flow Rate (mL/min) Aqueous 9.1 100 8 6.4 4.1 3.1 Recirculation 0 0 13 16 5 20 Org 22 22 22 22 22 22 [H+]/[OH-] 0.25 0.5 1 1.5 3 Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 97 | Page Source: L3 2026 Figure 10‐10: Concentration of elements over time in the Extraction stage of the solvent extraction system. Source: L3 2026 Figure 10‐11: Concentration of elements over time in the Scrub stage of the solvent extraction system.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 98 | Page Source: L3 2026 Figure 10‐12: Concentration of elements over time in the Strip 1 stage of the solvent extraction system. img170397038_50.jpg Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 99 | Page Figure 10‐13: Concentration of elements over time in the Strip 2 and Strip 3 stages of the solvent extraction system. Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 100 | Page Figure 10‐14: Distribution of the LREEs throughout the circuit. Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 101 | Page Figure 10‐15: Distribution of the SEG REEs throughout the circuit. Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 102 | Page Figure 10‐16: Distribution of the Tb, Dy, and Y throughout the circuit. Source: L3 2026 Figure 10‐17: Distribution of the HREEs throughout the circuit. 10.3.2.1.8 Area 800 - Chloride Recovery The ferric chloride pyrohydrolysis demonstration unit was designed and fabricated to demonstrate the technical feasibility of using pyrohydrolysis for the recovery of hydrochloric acid from ferric chloride solutions. A photo and a schematic of the demonstration unit are presented respectively as Figure 10‐18 and Figure 10‐19. The demonstration unit operated for 190 hours over 6 weeks and processed 122 gallons of ferric chloride produced by the iron recovery circuit.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 103 | Page img170397038_55.jpg Source: L3 2026 Figure 10‐18: Demonstration Ferric Chloride Pyro-Hydrolysis Reactor Unit Photo
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 104 | Page Source: L3 2026 Figure 10‐19: Demonstration Ferric Chloride Pyro-Hydrolysis Reactor Unit Schematic The unit was not optimized, and signs of corrosion are observable in the ferric oxide residue. This was specific to the pilot unit and is not representative of commercial operation. A typical residue produced during the operation is presented as Figure 10‐20. The distribution of elements in the residue is presented as Figure 10‐21. It should be noted that most of the base metals such as Mo, Ni and Cr assayed in the solid residue are likely corrosion products from the demonstration unit itself as they are not present in the ferric chloride liquor. The demonstration unit is designed as a spray roaster pyrohydrolyser, operating at 0.9 gallon per hour, at a temperature of 1200°F, and using natural gas burners.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 105 | Page Source: L3 2026 Figure 10‐20: Iron Oxide Residue Source: L3 2026 Figure 10‐21: Pyrohydrolysis residue elemental distribution. 10.3.3 Significant Factors A sufficient level of test work was conducted to support the design for the Hydrometallurgical Facility included in this Technical Report Summary and to reduce the risk of a fatal flaw in the flowsheet to a negligible level. (Here the term ‘fatal flaw’ is defined as an impairment or risk that is significant enough that if realized, would prevent the process from operating as intended, create a significant operating cost burden or result in a much lower recovery than expected for targeted metals). It’s
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 106 | Page important to note that optimization was not achieved in all areas, and some areas were not operated at the pilot or demonstration level. In addition, a vendor testing program is essential to the final equipment selection effort. Process optimization should continue to be explored both in preparation for and throughout detailed design. While the current model for rare earth separation has been successfully calibrated to a level sufficient for this Technical Report Summary, L3 recommends that the full circuit be piloted and that commercial samples be produced to perform the final calibration of the model for each circuit and to optimize the circuit design and operation. Finally, it is likely that the facility design could be optimized by increasing the project mass balance definition through process simulation of monthly elemental feed composition using the processing plant model and the compositions from the mine plan. 10.4 P YROMETALLURGY The purpose of the pyrometallurgical plant is to reduce the niobium oxide present in the Hydromet feed and convert it into a saleable ferroniobium metal. Pyrometallurgical test work has been conducted at multiple facilities, including: • Consulting & Testwork Services (XPS), Sudbury, Ontario, Canada (Spring 2015) • Kingston Process Metallurgy (KPM), Kingston, Ontario, Canada (Summer 2017) • Consulting & Testwork Services (XPS), Sudbury, Ontario, Canada (Fall 2025) • Consulting & Testwork Services (XPS), Sudbury, Ontario, Canada (ongoing, 2026) The 2015 and 2017 test programs did not fully characterize the chemical nature of the compounds present in the Hydromet feed; however, the material was identified as being rich in titanium. Subsequent Hydromet process improvements led to a significant reduction in titanium content by 2025, shifting the focus of the pyrometallurgical process toward the treatment of niobium–sodium–oxide compounds formed following calcination. More recent 2026 testing identified the presence of titanium oxide along with phosphorus-bearing niobium oxide phases, indicating variability in feed composition. Despite these variations, the aluminothermic reaction has consistently demonstrated the capability to produce a Fe–Nb alloy, supporting the development of multiple processing options pending confirmation of the ongoing test program. For the 2025 test campaign conducted at the Glencore XPS facility in Sudbury, Ontario, Canada, approximately 400 g of material was used for pyrometallurgical testing. The sample was supplied by L3 Process Development (Trois-Rivières, Québec, Canada), and the corresponding chemical analysis results are presented in Figure 10‐22. Hydrometallurgical process improvements implemented between 2019 and 2023 resulted in a significant reduction in titanium content in the product stream feeding the pyrometallurgical stage. Chemical analysis indicated that titanium was present only at trace levels, thereby mitigating previous concerns related to slag handling and slag chemistry. However, the chemical analysis did not provide information regarding the specific nature of the compounds present in the hydrometallurgical precipitate. X-ray diffraction (XRD) analysis identified a polyoxoniobate compound, Na₇(H₃O)(Nb₆O₁₉)·(H₂O)₁₄, as the dominant phase. This compound cannot be directly reduced in its existing form. Thermal decomposition at elevated temperature (approximately 1,022°F (550 °C)) results in the formation of sodium niobate (NaNbO₃),
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 107 | Page which can subsequently be reduced using aluminum in the presence of Fe₂O₃ to produce a ferroniobium alloy. For the 2025 test campaign, a discrete Fe0.₈₇Nb intermetallic phase was not directly identified. However, microstructural and compositional analyses of the produced alloy indicated Fe/Nb ratios consistent with the targeted FeNb alloy composition. These results confirm that, despite the complex chemical form of niobium in the Hydromet feed, the NaNbO₃ phase obtained after calcination can be effectively reduced through the pyrometallurgical process to produce a ferroniobium alloy meeting compositional expectation.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 108 | Page Source: L3 Process Development, 2026 Figure 10‐22: Chemical analysis results for the 400 g sample supplied by L3 Process Development
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 109 | Page While the pyrometallurgical test work successfully demonstrated the production of FeNb alloy, several aspects require further evaluation and optimization prior to advancement to detailed engineering: • Improved understanding and control of polyoxoniobate formation within the Hydromet circuit to ensure consistent feed chemistry • Larger-scale testing to optimize slag fluidity and enhance metal–slag separation • Optimization of flux composition to promote effective slag formation while maintaining acceptable refractory life and plant availability • Production of sufficient quantities of FeNb alloy to define product handling and shipping requirements • Evaluation of suitable crucible and refractory materials compatible with process chemistry and operating temperatures • Determination of the optimal Fe/Nb ratio based on both market requirements and process performance Pyrometallurgical test work conducted at Kingston Process Metallurgy confirmed the technical viability of producing a saleable FeNb alloy through aluminothermic reduction of niobium-bearing precipitates, including under conditions of elevated TiO₂ content. The test program demonstrated niobium recovery on the order of 96% and validated the use of hematite (Fe₂O₃) as an effective iron source. Within this framework, the pyrometallurgical circuit functions both as a metal production step and as a contributing mechanism for managing residual titanium-bearing compounds. Ongoing test work is evaluating process performance under updated feed conditions, with results pending at the time of this report. Variations in feed composition and compound speciation, particularly with respect to titanium-bearing phases, are expected to influence process behavior and phase distribution. The current program is therefore focused on confirming the applicability of earlier assumptions and refining the operating basis where required.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 110 | Page 11 M INERAL R ESOURCE E STIMATE 11.1 I NTRODUCTION The Mineral Resource Estimate for the Elk Creek Carbonatite Project was prepared by Dahrouge Geological Consulting USA Ltd. and has an effective date of June 30, 2026. The Mineral Resource Estimate was reported by Dahrouge Geological Consulting USA Ltd. The geology was modeled in Leapfrog Geo™ software, and the 3D bock model, grade estimation and classification were developed in Maptek Vulcan™ software. The resource encompasses four commodity streams niobium (Nb₂O₅), titanium (TiO₂), scandium (Sc), and total rare earth oxides (TREO) — hosted within a carbonatite intrusive complex located in Johnson County, Nebraska, USA. The methodology followed a systematic, domain-controlled estimation workflow comprising of source database validation, geological domaining, exploratory data analysis (EDA) and compositing, variography, ordinary kriging block model estimation, model validation, and resource classification. Each phase is described in the subsections that follow. It is of the opinion of the QP that all geological data collection, standard operating procedures and QA/QC procedures implemented during all programs since 2011 are of suitable quality to support the Mineral Resource Estimate and meet industry best practice standards. All issues relating to all relevant technical and economic factors likely to influence the prospect of economic extraction can be resolved with further work. 11.2 S OURCE D ATABASE The drillhole database used for resource estimation was managed in MX Deposit and transferred into Maptek Vulcan™ for compositing and estimation. The database was compiled and maintained by DGC for independent resource estimation. The resource database comprises 65 drill holes totalling approximately 127,569 ft (38,883 m) of HQ diamond core, with individual holes ranging from surface to a maximum depth of approximately 3,280 ft (1,000 m). All mineralised intercepts are located within the carbonatite intrusive complex and were drilled using diamond core methods. The full composite dataset contains 38,876 approximately 3.28 ft (one-meter) and 336 sub 3.28 foot (one-meter) composite intervals for a total of 39,098 composite sales spanning depths of 587 ft to 3,280 ft (179 m to 1,000 m) below surface, consistent with the sub-cropping nature of the deposit beneath approximately 656 ft (200 m) of Pennsylvanian marine sediment cover. The assay database includes determinations for the following analytes used in resource estimation: Nb₂O₅ (%), range 0.010– 4.093%; TiO₂ (%), range 0.001–11.570%; Sc (ppm), range 0–306 ppm; LREO (ppm, calculated), range 0–43,642 ppm; HREO (ppm, calculated), range 0–2,480 ppm; and TREO (ppm, calculated), range 0.01–44,004 ppm. LREO is calculated as the sum of La₂O₃, Ce₂O₃, Pr₂O₃, Nd₂O₃, and Sm₂O₃; HREO is calculated as the sum of Eu₂O₃, Gd₂O₃, Tb₂O₃, Dy₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Yb₂O₃, and Lu₂O₃; and TREO is the sum of LREO and HREO (14 rare earth oxides in total). Prior to compositing, DGC carried out standard database validation procedures within MX Deposit and Maptek Vulcan™ including checks for overlapping sample intervals, missing or inconsistent collar and survey data, and interval length consistency. No material errors were identified, and no
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 111 | Page significant corrections were required. The database was considered suitable for resource estimation purposes. 11.3 G EOLOGICAL D OMAINING Three estimation domains were defined by DGC for the Elk Creek resource estimate, based on the primary lithological controls on mineralisation within the carbonatite intrusive complex. Domain wireframes were constructed by DGC geologists in Leapfrog Geo™ using logged lithological contacts from all 65 drill holes in the resource database. Domain boundaries were interpreted to honour the principal lithological transitions observed in core logging and were not grade driven. All three domain boundaries were treated as hard boundaries for estimation purposes, meaning no composites from one domain were permitted to inform grade estimates in an adjacent domain. This treatment is justified by the pronounced grade contrasts between domains: Domain contacts were validated by visual inspection of drill sections and plans in Leapfrog Geo™. The three domains are described below: (1) MCARB – Magnetite / Dolomite Carbonatite (Primary Resource Domain) The MCARB domain encloses the magnetite-dolomite carbonatite, which is the principal host of economic mineralisation at Elk Creek. This domain contains 18,675, 3.28-foot (one-meter) composites from 46 drill holes and represents the highest- grade, most continuous mineralised unit in the deposit. Mean grades within MCARB of 0.560% Nb₂O₅, 2.434% TiO₂, 65.7 ppm Sc, and 2,837 ppm TREO are markedly elevated relative to all other domains. Grade distributions within MCARB are comparatively well-behaved, with coefficients of variation (“CV”) of 0.74 for Nb₂O₅ and 0.53 for TiO₂, consistent with a spatially coherent, continuously mineralised carbonatite body. (2) DOL_CARB – Dolomite Carbonatite (Peripheral Domain) The DOL_CARB domain is composed of dolomite carbonatite peripheral to and transitional with the MCARB unit. It contains 9,845 composites from 54 drill holes. Grades are substantially lower than MCARB across all analytes. The DOL_CARB domain is highly variable with CVs (coefficient of variation) of 1.12 for Nb₂O₅ and 1.53 for TiO₂. TREO grades in DOL_CARB are more erratic, with a high CV of 1.51 and a pronounced high-grade tail. (3) LAMP – Lamprophyre (Intrusive Dyke Domain) The LAMP domain encloses lamprophyre dykes that intrude the carbonatite complex. It contains 2,858 composites from 19 drill holes, spanning depths of 623 ft (190 m) to 3,317 ft (950 m). Lamprophyre is lithologically and geochemically distinct from the carbonatite units, with moderate Nb₂O₅ grades (mean 0.149%), elevated TiO₂ relative to DOL_CARB (mean 1.782%), and subdued Sc (mean 29.7 ppm). (4) Non Mineralized Domain There are 7,720 non mineralized composites in the database. These intervals are contained within the overlying Marine Sediments are were not used in the estimation. 11.4 D ENSITY D ETERMINATION AND A SSIGNMENT Dry bulk density values were determined from 3,382 core samples collected from diamond core during the 2025 drilling program. Density was measured by two methods: volumetric determination
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 112 | Page from dry weight and dimensional measurements (primary method, 2,955 measurements), and water immersion. Domain average dry bulk density values were calculated as the arithmetic mean of valid measurements within each domain and assigned uniformly to all estimated blocks within the corresponding domain wireframe. No spatial interpolation of density applied. Density statistics by domain are summarized in Table 11‐1. Table 11‐1: Bulk density by estimation domain Domain Number of Samples Mean SG (t/m3) Std. Dev. MCARB 1,471 3.06 0.23 DOL_CARB 898 2.87 0.17 LAMP 784 2.86 0.19 The large measurement populations and low standard deviations, particularly for DOL_CARB and LAMP, support the use of domain arithmetic means as representative density values. The elevated MCARB density (3.06 t/m3) is consistent with the abundant magnetite characteristic of the magnetite-dolomite carbonatite lithology that defines this domain. 11.5 E XPLORATORY D ATA A NALYSIS Exploratory data analysis (EDA) was carried out by DGC on the 3.28-foot (one-meter) composite database following domain assignment, conducted independently for the MCARB, DOL_CARB, and LAMP domains across Nb₂O₅, TiO₂, Sc, and TREO. 11.5.1 Distributed Analysis Grade distributions were examined using histograms, log-probability plots, and summary statistics (Figure 11‐1 through Figure 11‐4).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 113 | Page Source: DGC 2026 Figure 11‐1: Nb2O5 Grade distribution by domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 114 | Page Source: DGC 2026 Figure 11‐2:TiO2 Grade distribution by domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 115 | Page Source: DGC 2026 Figure 11‐3:Sc Grade distribution by domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 116 | Page Source: DGC 2026 Figure 11‐4:TREO Grade distribution by domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 117 | Page 11.5.2 Top Cut Analysis Top-cut values were determined using a combination of three methods: (1) log-probability plot disintegration; (2) CV stabilisation analysis; and (3) fixed-percentile evaluation at the 99th percentile used as a cross-check. Top-cut decisions were made on a per-analyte, per-domain basis. Sc was not top cut by any domain. Log probability plots show the upper tail tracking the fitted lognormal reference line continuously and is consistent with well behaved distributions that do not require outliner suppression (Figure 11‐5 through Figure 11‐8).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 118 | Page Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 119 | Page Figure 11‐5:Nb2O5 Log Probability Plot Source: DGC 2026 Figure 11‐6:TiO2 Log Probability Plot
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 120 | Page Source: DGC 2026 Figure 11‐7:Sc Log Probability Plot
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 121 | Page Source: DGC 2026 Figure 11‐8:TREO Log Probability Plot
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 122 | Page After analysis the results of the top cut by analyte and domain are contained in Table 11‐2. Table 11‐2: Top Cut Summary by Domain and Analyte Domain Analyte Cap Value Composites Affected % of Domain Mean Before Mean After Change MCARB Nb₂O₅ 3.000% 21 0.11% 0.5595% 0.5591% −0.1% MCARB TiO₂ Not applied — — 2.434% 2.434% — MCARB TREO Not applied — — 2,837 ppm 2,837 ppm — DOL_CARB Nb₂O₅ 1.000% 84 0.85% 0.1695% 0.1654% −2.4% DOL_CARB TiO₂ 3.570% 172 1.75% 0.5763% 0.5611% −2.6% DOL_CARB TREO 15,000 ppm 99 1.01% 2,045 ppm 1,995 ppm −2.5% LAMP Nb₂O₅ 1.200% 1 0.03% 0.1489% 0.1487% −0.1% LAMP TiO₂ Not applied — — 1.782% 1.782% — LAMP TREO Not applied — — 2,227 ppm 2,227 ppm — Source: DGC 2026 11.5.3 Declustering Cell declustering was applied independently to each analyte (Nb₂O₅, TiO₂, Sc, TREO) across all three domains using the Vulcan™ cell declustering algorithm configured to minimise the weighted average grade. Isotropic cell geometry was used throughout (Y and Z anisotropy = 1.0), with 5 offsets per cell size and 10 cell sizes tested across domain-specific ranges bracketing the representative drill spacing. The resulting declustered weight fields were passed directly to the Vulcan™ estimator as sample weighting inputs. The optimum cell sizes and resulting declustered means are presented in Table 11‐3. In the MCARB domain, declustered means are 7–14% lower than arithmetic means across all analytes, confirming a positive clustering bias in the high-grade core where infill drilling at closer spacing has preferentially sampled higher-grade material. The optimum cell sizes of 394-886 ft (120-270 m) in MCARB are consistent with the representative drill spacing of 164-246 ft (50-75 m) for Indicated resources and confirm that the declustering correction is geologically meaningful rather than an artefact of cell size selection. The declustered MCARB Nb₂O₅ mean of 0.484% is the reference grade against which the OK block model mean was benchmarked during validation, where the volume-weighted estimated mean was confirmed within 5% of this value. In DOL_CARB, the pattern is more variable. Nb₂O₅ and Sc show moderate negative clustering bias (−16% and −20% respectively), consistent with a peripheral domain where wider-spaced holes have sampled both higher and lower grade zones unevenly. The near-zero declustering correction for TiO₂ (+0.6%) and small positive correction for TREO (+3.0%) in DOL_CARB reflect the more erratic spatial distribution of these analytes in the peripheral carbonatite. The short optimum cell size for DOL_CARB TREO (10 m) indicates that TREO in this domain has no meaningful clustering bias at deposit scale and the arithmetic mean is effectively the declustered mean. In LAMP, declustering
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 123 | Page corrections are small (< 8%) across all analytes, consistent with the more uniform drill spacing in that domain. Table 11‐3: Optimum cell size ranges used for cell declustering by domain and analyte. Domain Analyte Units Arithmetic Mean Capped Mean Optimum Cell Size (m)Declustered Mean MCARB Nb₂O₅ % 0.5595 0.5591 120 0.4837 TiO₂ % 2.434 2.434 250 2.224 Sc ppm 66 66 270 57 TREO ppm 2,837 2,837 260 2,634 DOL_CARB Nb₂O₅ % 0.1695 0.1654 290 0.1391 TiO₂ % 0.576 0.561 280 0.565 Sc ppm 22 22 280 17 TREO ppm 2,045 1,995 10 2,055 LAMP Nb₂O₅ % 0.1489 0.1487 290 0.1433 TiO₂ % 1.782 1.782 280 1.718 Sc ppm 30 30 120 28 TREO ppm 2,227 2,227 20 2,324 Source: DGC 2026 11.5.4 Correlation Analysis Inter-element correlations were evaluated through bivariate scatter plots and Pearson correlation matrices within each domain (Table 11‐4). Strong positive correlations exist between Nb₂O₅ and TiO₂ within the MCARB domain, consistent with co- occurrences pyrochlore, magnetite, and rutile/ilmenorutile in the magnetite-dolomite carbonatite assemblage. Sc correlates positively with both Nb₂O₅ and TiO₂ in MCARB, supporting co-product NSR modelling. TREO correlations with base metals are moderate in MCARB and weaker in DOL_CARB, reflecting more erratic REE distribution in peripheral carbonatite.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 124 | Page Table 11‐4: Pearson Correlation Matrix (Capped Composite Grades by Domain) img170397038_68.jpg Source: DGC 2026 11.6 D ATA P REPARATION Assay intervals were composited to a uniform 3.28 ft (1 m) downhole length using length-weighted averaging within Maptek Vulcan™. Compositing was performed independently within each estimation domain, with domain boundaries treated as hard constraints such that no composite interval spans more than one domain. At domain contacts, residual intervals shorter than the
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 125 | Page nominal composite length were assigned to the dominant domain by majority interval length. The resulting composite database contains 39,098 samples with a length of 3.28 ft (1 m): 18,675 samples in MCARB, 9,845 samples in DOL_CARB, 2,858 samples in LAMP and 7,720 non mineralized samples. The mean composite length across all domains is 0.994 m, confirming a highly uniform support with minimal residual interval effects. Capped composite grades were used as inputs to variography and estimation. 11.7 V ARIOGRAPHY Experimental semivariograms were computed and modelled by DGC for each estimation analyte within each domain using capped composite grades. All variograms were standardised to a total sill of 1.0. For all other domain-analyte combinations, the nugget was determined by visual fitting to the y-intercept of the experimental variogram, as data density in those domains and directions was insufficient to compute reliable downhole variograms. All structures were fitted using spherical models. The MCARB domain Nb₂O₅ variogram was computed directionally; all other domain-analyte combinations were modelled omni-directionally due to data density constraints. The complete variogram model parameters are presented in Table 11‐5. Table 11‐5: Variogram Model Parameters: All Domains and Analytes Domain Analyte Nugget Str. Type Sill (C) Maj Range (m) Semi (m) Min (m) Orientation MCARB Nb₂O₅ 0.30 1 Sph 0.70 110 70 30 Az30°/Pl75°/Dip90° MCARB TiO₂ 0.30 1 Sph 0.70 35.8 35.8 35.8 Omni MCARB Sc 0.14 1 Sph 0.86 268.6 268.6 268.6 Omni MCARB TREO 0.35 1 Sph 0.42 60 60 60 Omni MCARB TREO — 2 Sph 0.23 319 319 319 Omni DOL_CARB Nb₂O₅ 0.30 1 Sph 0.70 38 38 38 Omni DOL_CARB TiO₂ 0.30 1 Sph 0.70 11.8 11.8 11.8 Omni DOL_CARB Sc 0.20 1 Sph 0.80 31.8 31.8 31.8 Omni DOL_CARB TREO 0.20 1 Sph 0.80 380 380 380 Omni LAMP Nb₂O₅ 0.25 1 Sph 0.75 92.4 92.4 92.4 Omni LAMP TiO₂ 0.25 1 Sph 0.75 74.2 74.2 74.2 Omni LAMP Sc 0.13 1 Sph 0.87 14.0 14.0 14.0 Omni LAMP TREO 0.30 1 Sph 0.70 191 191 191 Omni Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 126 | Page Source: DGC 2026 Figure 11‐9:Nb2O5 Ortho Directional Variogram for MCarb Domain.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 127 | Page Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 128 | Page Figure 11‐10: Sc Omni Directional Variogram for MCarb Domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 129 | Page Source: DGC 2026 Figure 11‐11: TiO2 Omni Directional Variogram for MCarb Domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 130 | Page Source: DGC 2026 Figure 11‐12: TREO Omni Directional Variogram for MCarb Domain.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 131 | Page The MCARB Nb₂O₅ variogram demonstrates clear anisotropy with a major range of 361 ft (110 m) oriented steeply (Az30°, Pl75°), consistent with the near-vertical geometry of the carbonatite body. The minor range of 98 ft (30 m) reflects the across- strike horizontal continuity. Sc in MCARB has the longest range (882.5 ft, 269 m) and lowest nugget (0.14) of all MCARB analytes, consistent with its homogeneous distribution (CV 0.43). TREO in MCARB required a two-structure nested model capturing both local REE clustering (197 ft, 60 m) and broader deposit-scale continuity (1,046 ft, 319 m). In DOL_CARB, Nb₂O₅ displays very short-range continuity (125 ft, 38 m) while TiO₂, Sc, and TREO have long ranges reflecting broad compositional trends across the peripheral carbonatite rather than local high-grade continuity. In LAMP, Sc has an unusually short range (46 ft, 14 m) with a low nugget, while other analytes show moderate ranges of 243-627 ft (74–191 m). 11.8 B LOCK M ODEL R ESOURCE E STIMATION 11.8.1 Block Model Configuration The resource block model was constructed in Maptek Vulcan™ (Version 2025) using a parent block size of 16.4 ft × 16.4 ft × 16.4 ft (5 m × 5 m × 5 m) throughout the model volume. Each block was discretized into a 4 × 4 × 4 grid of 64 points for kriging weight calculation, providing accurate volume-weighted grade estimates. The block model is named 'elk_creek_bm_dec2025.bmf'. The model was constrained by the geological domain wireframes described in Section 11.3, with each block coded to a single domain using the hard boundary assignment. The block model configuration parameters are summarised in Table 11‐6. Table 11‐6: Block Model Configuration Parameters Parameter Value Notes Model geometry Block size (X × Y × Z) 16.4 ft × 16.4 ft × 16.4 ft (5 m × 5 m × 5 m)Parent blocks only Sub-blocking None Fixed parent block; no sub-cells Block discretization (kriging) 4 × 4 × 4 = 64 points per block Per-block point grid for OK weight calculation Model rotation (Bearing / Dip / Plunge)0° / 0° / 0° Axis-aligned; no rotation applied Model origin and extents Origin (Easting) 739,700.000 m E SW lower corner of model volume Origin (Northing) 4,461,000.000 m N SW lower corner of model volume Origin (Elevation) −650.000 m RL Below sea level Block count and volume Blocks in X (Easting) 130 650 m E–W extent Blocks in Y (Northing) 185 925 m N–S extent
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 132 | Page Parameter Value Notes Blocks in Z (Elevation) 170 2,779 ft (850 m) vertical extent Total blocks in model 4,088,500 130 × 185 × 170 Model bounding box Easting range 739,700 – 740,350 m E 650 m E–W Northing range 4,461,000 – 4,461,925 m N 925 m N–S Elevation range −650 to +200 m RL 2,779 ft (850 m) vertical Software and file Estimation software Maptek Vulcan™ (Version 2025) Ordinary Kriging estimation Block model file elk_creek_bm_dec2025.bmf Vulcan™ native block model format Source: DGC 2026 11.8.2 Estimation Method Grade estimation was carried out using Ordinary Kriging (OK) for all analytes (Nb₂O₅, TiO₂, Sc, and TREO) within all three domains. OK was selected on the basis of the moderate CVs in the primary MCARB domain (CV 0.43–0.74). The higher CVs in DOL_CARB for TiO₂ and TREO (CV 1.45–1.53 post-capping) were managed through top-cutting. Declustering weights were applied to all analytes in all domains during the OK run. An independent nearest neighbour (NN) check model was run for validation purposes (Section 14.8). All estimation used capped composite grades as inputs. Dry bulk density values were determined from 3,382 core samples collected from the 2014 and the 2025 drilling program. The density statistics and assigned values are summarized in Table 11‐7 below: Table 11‐7: Bulk Density Summary by Geologic Domain Domain Measurements (n) Mean SG t/m3) Std dev (t/m3) Assigned Density (t/m3) MCARB 1,471 3.06 0.23 3.06 DOL_CARB 898 2.87 0.17 2.87 LAMP 784 2.86 0.19 2.86 Source: DGC 2026 The elevated MCARB density (3.06 t/m³) is consistent with the abundant magnetite in the magnetite-dolomite carbonatite lithology. 11.8.3 Estimation Pass Structure A three-pass estimation strategy was employed for all domains. Pass 1 (flag = 1) uses tight search parameters and strict composite requirements, estimating only well-informed blocks. Pass 2 (flag = 2) expands the search and relaxes composite requirements for areas of moderate drill density. Pass 3 (flag = 3) uses the full variogram range and minimum composite requirements as a fill pass for peripheral blocks. For Nb₂O₅ in MCARB, Pass 3 estimated zero additional blocks, confirming that the
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 133 | Page MCARB Nb₂O₅ model is fully populated within two passes. The DOL_CARB Nb₂O₅ Pass 3 search has no per-hole composite limit, consistent with its use as a low-confidence fill pass in a sparse data area. The complete estimation parameters for all domain-analyte-pass combinations, as verified from the Vulcan™ BEF output files, are presented in Table 11‐8. Table 11‐8: Multi-Pass Estimation Parameters Domain Analyte Pass Search Maj (m) Search Semi (m) Search Min (m) Max Smp Min Smp Min Holes Max/Hole MCARB Nb₂O₅ 1 58 45 20 14 6 3 4 MCARB Nb₂O₅ 2 100 80 40 16 4 2 4 MCARB Nb₂O₅ 3 170 130 60 12 4 1 4 MCARB TiO₂ 1 50 35 20 16 8 3 4 MCARB TiO₂ 2 80 60 30 16 8 2 4 MCARB TiO₂ 3 170 120 60 12 4 1 4 MCARB Sc 1 60 45 20 16 8 3 4 MCARB Sc 2 120 85 35 14 6 2 4 MCARB Sc 3 270 180 60 12 4 1 4 MCARB TREO 1 75 75 35 16 8 3 4 MCARB TREO 2 120 120 55 24 6 2 4 MCARB TREO 3 220 220 90 32 4 1 4 DOL_CARB Nb₂O₅ 1 22 20 14 12 6 3 4 DOL_CARB Nb₂O₅ 2 40 35 25 16 4 2 4 DOL_CARB Nb₂O₅ 3 230 155 55 32 2 1 4 DOL_CARB TiO₂ 1 100 70 40 16 8 3 4 DOL_CARB TiO₂ 2 200 140 80 14 6 2 4 DOL_CARB TiO₂ 3 300 210 120 12 4 1 4 DOL_CARB Sc 1 50 38 18 16 8 3 4 DOL_CARB Sc 2 100 70 30 14 6 2 4 DOL_CARB Sc 3 230 155 55 32 2 1 8 DOL_CARB TREO 1 212 212 212 16 8 3 4 DOL_CARB TREO 2 264 264 264 14 6 2 4
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 134 | Page Domain Analyte Pass Search Maj (m) Search Semi (m) Search Min (m) Max Smp Min Smp Min Holes Max/Hole DOL_CARB TREO 3 380 380 380 12 4 1 4 LAMP Nb₂O₅ 1 60 50 35 14 6 3 4 LAMP Nb₂O₅ 2 105 85 65 16 4 2 8 LAMP Nb₂O₅ 3 180 145 95 12 4 1 4 LAMP TiO₂ 1 50 35 20 16 8 3 4 LAMP TiO₂ 2 80 55 30 16 4 2 4 LAMP TiO₂ 3 120 85 45 12 4 1 4 LAMP Sc 1 70 50 22 16 8 3 4 LAMP Sc 2 140 95 40 14 6 2 4 LAMP Sc 3 300 200 70 12 4 1 4 LAMP TREO 1 75 75 75 16 4 3 4 LAMP TREO 2 120 120 120 24 4 2 4 LAMP TREO 3 220 220 220 32 2 1 4 Source: DGC 2026 11.9 M ODEL V ALIDATION Model validation comprised four components: (1) global mean comparison between the OK model, declustered composite mean, and independent NN check model; (2) swath plot analysis in east–west, north–south, and vertical directions; (3) grade- tonnage curve comparison at multiple cut-off grades; and (4) visual inspection of estimated grades on drill sections and plans. For each domain and analyte, the volume-weighted OK block model mean was within 5% of the declustered composite mean, satisfying the standard acceptance threshold for unbiased estimation. The close agreement between OK and NN check model means provides additional confidence that the estimation parameters are producing geologically reasonable results. Swath plots showed the OK model tracking composite swath means acceptably in all three directions with no persistent directional bias. Local deviations are attributable to kriging smoothing and variable composite density within swath panels. Grade- tonnage curves for the OK model are consistent with composite and NN curves across all relevant cut-off ranges, with the expected smoothing effect observed. Visual inspection on representative cross-sections and longitudinal projections confirmed geologically coherent grade transitions with no artefacts at domain boundaries.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 135 | Page Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 136 | Page Figure 11‐13: Swath Plot Nb2O5 for the MCarb Domain Source: DGC 2026 Figure 11‐14: Swath Plot Sc for the MCarb Domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 137 | Page Source: DGC 2026 Figure 11‐15: Swath Plot TiO2 for the MCarb Domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 138 | Page Source: DGC 2026 Figure 11‐16: Swath Plot TREO for the MCarb Domain
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 139 | Page The Elk Creek block model is considered unbiased and geologically reasonable. The model is suitable for mineral resource classification and reporting. 11.10 M INERAL R ESOURCE C LASSIFICATION Mineral Resource classification was assigned in accordance with the definitions and requirements of Regulation S-K, Subpart 1300. Classification was based on per-block estimation quality flags (pass number) and slope of regression (SoR) values computed during the OK estimation run, supplemented by geological confidence review. Table 11‐9: Mineral Resource Classification Material Classification Nb₂O₅ flag Nb₂O₅ SoR Sc flag Sc SoR TREO flag TREO SoR Measured 1 > 0.3 1 > 0.3 1 > 0.3 Indicated ≤ 2 — ≤ 2 — ≤ 2 — Inferred ≤ 3 — ≤ 3 — ≤ 3 — Source: DGC 2026 The requirement that all three primary analytes meet classification thresholds simultaneously ensures that blocks are well- constrained across the full commodity suite contributing to NSR value. Classification boundaries were reviewed in three dimensions to confirm spatial coherence. The MCARB domain, with the greatest drill density and strongest variogram continuity, hosts the majority of Measured and Indicated resources. The DOL_CARB and LAMP domains contribute predominantly to the Inferred category. 11.11 R EASONABLE P ROSPECTS OF E VENTUAL E CONOMIC E XTRACTION The Elk Creek deposit is hosted within a carbonatite intrusive complex at depths ranging from approximately 590 ft to 3,280 ft (180 m to 1,000 m) below surface, beneath approximately 656 ft (200 m) of Pennsylvanian marine sediment cover with no surface outcrop. The deposit is considered amenable to underground bulk mining by longwall stoping, consistent with the geometry of the MCARB domain as a large, continuously mineralised tabular to sub-cylindrical carbonatite body. Reasonable prospects of eventual economic extraction were evaluated by applying an NSR cut-off value to the block model. Only blocks with NSR values exceeding the cut-off and assigned a Measured, Indicated, or Inferred classification were included in the mineral resource statement. The NSR model incorporates process recoveries of 86.72% for Nb, 83.65% for TiO₂, and 92.00% for Sc, representing the concentration circuit recoveries applied in the block model NSR calculation as derived from metallurgical test work results described in Section 13 of this report. The deposit is in a politically stable jurisdiction (Nebraska, USA) with established infrastructure and a supportive regulatory environment. There are no known legal, environmental, or social factors that would preclude eventual economic extraction at the time of reporting. The deposit is in a politically stable jurisdiction (Nebraska, USA) with established infrastructure and a supportive regulatory environment. There are no known legal, environmental, or social factors that would preclude eventual economic extraction at the time of reporting.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 140 | Page 11.12 C UT -O FF G RADE The mineral resource is reported at a cut-off of NSR greater than US$218/ton (US$240/tonne) of mineralised material. NSR values were calculated for each block within Maptek Vulcan™ by applying elemental conversion factors, metallurgical recoveries, and assumed commodity prices to the estimated grades of Nb₂O₅, TiO₂, Sc, Tb₂O₃, NdPr Oxide, and Dy₂O₃. Table 11‐10: NSR Conversion, Recoveries and Pricing Product Conversion Factor Recovery (%) Price (US$/kg) Ferroniobium (FeNb) 0.699 × Nb₂O₅ 86.72 52 Sc₂O₃ 1.530 × Sc ppm 92 2,000.00 TiCl₄ 2.350 × TiO₂ 83.65 1.86 Tb₂O₃ — 92 1,845.00 NdPr Oxide — 92 125 SEG Carbonate — 92 8.97 Source: DGC 2026 The NSR cut-off of US$218/ton (US$240/tonne) was derived from preliminary operating and capital cost estimates developed during the 2026 Elk Creek Study and represents the minimum block value at which mineralised material is considered economically viable to mine and process under the assumed cost and price parameters. At the MCARB domain mean grades (0.560% Nb₂O₅, 2.434% TiO₂, 65.7 ppm Sc), the calculated NSR is approximately US$409/ton, confirming the mean MCARB grade is well above the reporting cut-off. The NSR formula incorporates six product streams: FeNb, Sc₂O₃, TiCl₄, Tb₂O₃, NdPr Oxide and SEG Carbonate. Of these, Nb₂O₅, TiO₂ and Sc are reported as mineral resource grades; Tb₂O₃, NdPr Oxide, and SEG Carbonate were estimated independently and contribute to the NSR calculation but are not reported as separate resource attributes. 11.13 M INERAL R ESOURCE T ABULATION The in-situ Elk Creek Mineral Resource estimate, effective June 30, 2026, is presented in Table 11‐11. The estimate was prepared by Dahrouge Geological Consulting USA Ltd., in accordance with Regulation S-K 1300. Table 11‐11: Elk Creek Mineral Resource Estimate Inclusive of Reserve - Effective June 30, 2026 Classification Cut-off NSR (US$/ton) Tonnage (Mtons)Nb₂O₅ (%) TiO₂ (%) Sc (ppm) TREO (%) Measured 218 21.7 0.61 2.46 69.1 0.35 Indicated 218 187.4 0.50 2.36 59.85 0.36 Measured + Indicated 218 209.1 0.51 2.38 60.81 0.36 Inferred 218 169.2 0.38 2.14 51.02 0.39
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 141 | Page Table 11‐12: Elk Creek Mineral Resource Estimate Exclusive of Reserve – Effective June 30, 2026 Classification Cut-off NSR (US$/ton) Tonnage (Mtons)Nb₂O₅ (%) TiO₂ (%) Sc (ppm) TREO (%) Measured 218 14.1 0.53 2.05 47.6 0.39 Indicated 218 149.0 0.43 1.70 42.5 0.39 Measured + Indicated 218 163.1 0.44 1.89 45.3 0.39 Inferred 218 169.2 0.38 2.14 51.02 0.39 Source: DGC 2026 Notes: (1) Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resource will be converted to Mineral Reserves. (2) Mineral Reserves are reported separately in Section 12 of this report. (3) Prepared in accordance with Regulation S-K 1300 (4) NSR cut-off of US$218/ton (US$240/tonne) based on longhole stoping underground mining; incorporates metallurgical recoveries of Nb 86.72%, TiO₂ 83.65%, Sc 92.00%, and REE by-products 92.00%, at metal prices of US$52.00/kg Nb, US$2,000.00/kg Sc, US$1.86/kg TCl4, US$1,845.00/kg Tb₂O₃, US$125.00/kg NdPr, and US$8.97/kg SEG carbonate. (5) TREO = LREO + HREO expressed as a percentage (TREO% = TREO ppm ÷ 10,000) (6) Tonnages in millions of short tons (Mt). Grades rounded to reflect the approximate nature of resource estimates. (7) Totals may not sum due to rounding. (8) Qualified Person: Dahrouge Geological Consulting USA Ltd., effective date June 30, 2026. 11.14 M INERAL R ESOURCE S ENSITIVITY The sensitivity of the Elk Creek Mineral Resource to the NSR cut-off grade is summarised in Table 11‐13. The base case cut- off of US$218/ton is highlighted. The resource responds predictably to changes in the NSR cut-off — lower cut-offs capture additional lower-grade peripheral material while higher cut-offs progressively exclude sub-marginal blocks. Table 11‐13: Elk Creek Mineral Resource Sensitivity NSR Cut-Off (US$/t)Tonnage (Mt) Nb₂O₅ (%) TiO₂ (%) Sc (g/t) TREO (%) 136 216.7 0.50 2.24 59 0.36 163 215.2 0.50 2.25 60 0.36 190 212.6 0.50 2.27 60 0.36 218 209.1 0.51 2.38 61 0.36 245 201.8 0.52 2.33 62 0.36 272 195.3 0.53 2.35 63 0.36 300 188.1 0.55 2.38 64 0.36 Source: DGC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 142 | Page 11.15 R ELEVANT F ACTORS The following factors are considered relevant to the interpretation and use of the Elk Creek Mineral Resource estimate. Geological factors. The deposit has no surface exposure and is defined entirely by diamond drilling and geophysical interpretation. While domain wireframes are internally consistent and supported by strong lithological logging, the absence of outcrop means geological uncertainty at the deposit margins is higher than for a surface-exposed deposit. Inferred resources in the peripheral DOL_CARB domain carry correspondingly higher geological uncertainty. Metallurgical factors. The NSR cut-off incorporates process recoveries derived from demonstration scale metallurgical test work. The recoveries used are: Nb 86.72%, TiO₂ 83.65%, Sc 92.00%, and REE by-products 92.00%. Overall plant recoveries incorporating downstream processing steps may differ from these concentration circuit values. Variations in metallurgical recovery across any of the primary commodities could have a material effect on the NSR value of individual blocks and consequently on reported resource tonnage at the stated cut-off. Title and surface rights. NioCorp Developments Ltd. holds the Elk Creek property in fee simple, with full ownership of both surface and mineral rights. There are no known title disputes or encumbrances that would preclude resource development. Royalties and encumbrances. The entirety of the Mineral Resource is subject to a 2% NSR royalty held by the former owners of the lands that host the Resource. Permitting. The Elk Creek project is fully permitted. All material permits required for the proposed mining and processing operations have been obtained. There are no known outstanding permitting requirements that would materially affect the development timeline or the validity of the mineral resource estimate. Taxation. The project will be subject to standard federal and Nebraska state income tax, along with property taxes payable to Johnson County, Nebraska. Socio-economic and political factors. The Elk Creek project is located in Johnson County, Nebraska, USA, a politically stable jurisdiction with a well-established legal and regulatory framework for mining development. There are no known socio- economic, community, or indigenous land use factors that would materially affect the reasonable prospects of eventual economic extraction. Commodity price factors. The NSR model is based on commodity price assumptions current at the time of the 2026 Elk Creek Study and are based on independent market studies. Commodity prices may be subject to market volatility and are influenced by supply concentration, emerging technology demand, and geopolitical factors. A material decline in any primary commodity price, particularly niobium and scandium which dominate the NSR, would reduce the economic viability of the deposit and could reduce reportable resource tonnage at the stated cut-off. Classification and data density. The Inferred resource (153.5 Mt / 169.2 Mtons) is large relative to the Indicated + Measured resource (189.8 Mt / 209.1 Mtons), reflecting the significant volume of DOL_CARB domain drilled at wider spacing. Conversion of Inferred to Indicated resources would require infill drilling, particularly in the peripheral carbonatite. Reporting code compliance. Mineral Resource classification was assigned in accordance with the definitions and requirements of Regulation S-K 1300. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Mineral Reserves are reported separately in Section 12 of this report and are a subset of the total Mineral Resources reported herein. Inferred Mineral Resources are considered too speculative geologically to have the economic considerations
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 143 | Page applied to them that would enable them to be categorised as Mineral Reserves, and there is no certainty that Inferred Mineral Resources will be upgraded through continued exploration. 12 M INERAL R ESERVE E STIMATES 12.1 I NTRODUCTION The Project is currently in the late stages of exploration and has advanced to initial development as of the report date. Based on geotechnical information and mineralized geometry, an underground long hole stoping method (LHS) has been determined to be suitable for the Deposit. Paste backfill will be used to allow for higher recovery of material. “Modifying factors” were applied to the mineral resources to allow for the defining of mineral reserves as stated herein. Table 12‐1: Mineral reserves as of June 30, 2026 and stated in this report 2026 Reserve Mineral Reserve Classification Cut-off NSR Tonnage Grade Grade Grade Grade (US$/ton) (ton) (NbO%) (TiO%) (Sc ppm) (TREO %) Proven 218 7,570,098 0.760 2.70 71.5 0.32 Probable 218 38,359,365 0.759 2.67 68.8 0.35 Total 218 45,929,462 0.759 2.68 69.3 0.34 Source: Amplify Mine Planning, 2026 The stopes dimensions are planned at 49ft wide while using a stope length that varies - based on Nb2O5 mineralization grade - with a maximum of 49 ft and minimum of 33 ft per stope and a level spacing height of 131 ft. The variation on stope length allows optimizing the Nb2O5 grade with a minimal increase in operating costs. The spacing of 131 ft between levels was designed based in part on the analysis of beneficial estimated operating and sustaining capital costs. Three ore blocks (“horizons”) are identified and are composed of several mining levels that are above a designed sill pillar level and contain stopes which are planned to be mined in their entirety on a primary and secondary mining sequence (Figure 12‐1). This mining strategy allows cemented paste backfill to be placed and cured between mining cycles. Each stope in the block is mined using a bottom-up excavation approach and is expected to recover 95% of the in-place volume in each stope. A paste backfill mixture of tailings that includes cement and/or fly ash as a binder and strengthening agent will be placed in the emptied primary stope and allowed to cure prior to mining the secondary stope on either side of the primary. This methodology allows mining of ore and establishes an early start to the mining of the upper mining block above the first sill pillar level while at the same time allowing the development of the lower mining blocks. The cemented backfill was designed to have adequate strength for mining adjacent to filled stopes, thus eliminating the need for rib pillars. A partially recoverable sill pillar level designed to be left between each of these mining blocks until such time as the life-of-mine sequence plans their extraction. Extracting ore from the sill pillar level is expected to be roughly 62.5% of the in-place volume using production up- holes through the lower 82ft of the 131ft thick sill pillar and is accounted for within the reserve statement. 2 5 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 144 | Page Source: Amplify Mine Planning, 2026 Figure 12‐1:2026 Elk Creek Study Mine Design There will be two spiral ramps (a primary “access” ramp and secondary “haulage” ramp) driven from a box cut type of surface excavation through the strata located in the first 655ft from surface and to efficiently reach the mineral deposit. Both ramps are excavated at the same time using conventional drifting methods in conjunction with a bolting, shotcrete, and grouting ground control procedure through the first 655ft from the surface to secure the strata around the ramps. The primary “access” ramp is designed to facilitate main access and equipment/services movement, serve as the intake air ventilation, and provide mine material logistics. A short ventilation shaft connecting the primary access ramp to the surface will also be excavated to connect the ramp to the surface mounted mine fans and create the intake mine ventilation system. The haulage ramp will be excavated to a deeper elevation than in the previous feasibility studies to reflect an increase in defined mineral reserves. This also allows earlier access to higher grade ore in the central portion of the mine and to access higher grade ore in the lower mining blocks with a more efficient material handling system. The ventilation system is engineered as a positive-pressure (“push”) ventilation network, with surface facilities providing conditioned intake air to address the humid continental climate of southeast Nebraska (hot, humid summers and cold winters). Detailed airflow quantities, fan configurations, auxiliary ventilation, refrigeration, heating, and control philosophy are presented in subsequent sections of this report. The secondary “haulage” ramp and return ventilation system is designed to serve as the mine exhaust air system and a second means of mechanical movement/escapeway. In addition, when mining the secondary access ramp (which will be as deep as the haulage ramp), it allows for an earlier start to key lateral development using a periodic ventilation connection drift between the two ramps. The secondary haulage ramp will install and operate a “Railveyor©” (“Railveyor”) conveying system to transport the ore from the loadout drifts to the surface stockpile. The Railveyor system is sized to support the daily production requirements of the mine and mill.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 145 | Page Mined ore will be transported from the stopes via the access level drifts to the primary haulage Railveyor ramp system using underground LHDs filling trucks, which then dump into ore passes, and on to a conveyor loading into the Railveyor cars for transport out of the mine. Access and infrastructure development for the underground workings was designed to support the mining method and was sized based on ventilation, mining equipment specifications, and production rate requirements. Surface infrastructure and tailings were designed to match the underground production rate requirements. 12.2 C ONVERSION , A SSUMPTIONS , P ARAMETERS & M ETHODS Defined blocks of Measured Resources were converted to Proven Reserves and Indicated Mineral Resources were converted to Probable Mineral Reserves by applying the appropriate modifying factors, as described within this sub-section, tied to potential mining block shapes created during the mine design process. The undiluted tons and grade of each potential mining block are based on the resource block model estimated by DGC as described in Section 11 of this report. All Mineral Reserve tonnages are expressed as "dry" tons (i.e., no moisture) and are based on the density values stored in the block model. 12.2.1 Dilution Mining dilution of approximately 6% by volume was applied to all stopes and development excavations, based on geotechnical analysis and recommendations. This figure is an average based on calculating 3% dilution by volume for the primary stopes, 9% dilution by volume for the secondary stopes, and 5% dilution by volume for ore development. The mining dilution percentage was added to the designed tonnage to account for unplanned sources of dilution, such as backfill and host rock around the periphery of the ore mass. Mining dilution of host rock from around the periphery of the ore mass has been applied with zero grade as a conservative assumption even though some sources of this type of dilution will likely carry grade. The primary stopes will have extraneous ore, host rock and unconsolidated backfill as potential material that will slough into them while being extracted. It should be noted that the ore portion of the sloughed material is not included in calculation of the 3% dilution factor, since this ore is accounted for in the adjacent stopes. The higher dilution factor for the secondary stopes is due to the fact these stopes have more sources of waste material with no grade and less ore from adjacent stopes; therefore, a higher dilution factor of 9% has been applied to them. The 5% dilution of development drifts is the result of the mining process, which can potentially be exposed to higher amounts of initial dilution material. As stated in Section 13.2, the thickness of external dilution is estimated as equivalent linear overbreak/slough (ELOS), for moderately weathered carbonatite, and for fresh to slightly weathered carbonatite. Sidewall and back dilution are not expected to be a problem because the dilution in the primary stopes (i.e. from adjacent secondary stopes) will be at grade, and dilution from the secondary stopes is managed by controlling backfill strength. As shown in Figure 12‐2, sources of mining dilution for primary stopes include: • Backfill material on the floor/sill with no grade. • Backfill material from the hangingwall end with no grade if the stope is adjacent to a previously mined stope.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 146 | Page • Low grade periphery rock dilution in the hangingwall or footwall if the stope is not adjacent to other stopes. As shown in Figure 12‐2, sources of mining dilution for secondary stopes include: • Backfill material on the floor/sill with no grade. • Backfill material from the hangingwall end with no grade if the stope is adjacent to a previously mined stope. • Low grade periphery rock dilution in the hangingwall or footwall if the stope is not adjacent to other stopes. • For most situations, backfill material on both sidewalls with no grade. Source: Nordmin, 2019 Figure 12‐2:Sources of Mining Dilution for Typical Stope Layout (Not to scale).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 147 | Page Table 12‐2: Potential sources of mining dilution by stope type (primary and secondary) for a typical stope geometry and standard mining practices in the ground conditions expected at Elk Creek. Footwall P2 P1 P0 S2 S1 S0 P2 P1 P0 S2 S1 S0 P2 P1 P0 S2 S1 S0 Primary Stopes Secondary Stopes P2 P1 P0 S2 S1 S0 Hanging Wall Dilution - Rock Yes Yes Footwall Dilution - Rock Yes Yes Hanging Wall Dilution - Backfill Yes Yes Yes Yes Footwall Dilution - Backfill Sidewalls - Rock (Ore) Sidewalls - Backfill Yes Yes Yes Floor/Sill Dilution - Backfill Yes Yes Yes Yes Yes Yes Source: Nordmin, 2019 12.2.2 Recovery A stope recovery factor of 95% was calculated for mining all the primary and secondary stopes. The following parameters in combination were considered in calculating this factor: • Potential material loss into backfill (floor) of 0.4 m. • Potential material loss to side and end walls (under blast) of 0.2 m. • Potential material loss to mucking along edges and in blind corners (using limited visibility). • Additional potential loss factor due to rockfalls, sudden unanticipated regional stress load relief, and other geotechnical reasons. A development recovery factor of 95% was also used for all horizontal drift development because it is subject to the same potential material loss as stated above. A recovery factor of 62.5% was applied to sill pillar stopes was used to reflect the lower expected recovery of back-stopes excavated under previously mined stopes above.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 148 | Page 12.2.3 COG / NSR Calculation Net Smelter Return (NSR) is a commonly accepted method of evaluating a mineral deposit where revenue is generated from multiple elements. NSR is defined as the proceeds from the sale of mineral products after deducting off-site processing and distribution costs. NSR is typically expressed on a dollar per tonne basis. An NSR (Net Smelter Return) approach was used and focused on targeted amounts of Nb2O5 and considers planned mining of four (4) elements (Nb2O5, Sc, TiO2, rare earths) that results in generating eight (8) separate products (FeNb, Sc2O3, TiCl4, NdPr Oxide, Tb2O3, Dy2O3, SEG Carbonate, Heavies Carbonate). Stope optimization was completed to identify economic mining areas based on these saleable products. The 3D mine design was completed on an elevated cut-off grade (CoG), which achieved an average of over 2.5 times the actual calculated cut-off grade. Recoveries used are based on metallurgical test work discussed in Section 10. The NSR was evaluated for each block in the 3D geologic resource block model as of the report date. Table 12‐3 shows NSR parameters and an example NSR calculation for an individual block. Table 12‐3: Example of an NSR Block Calculation Input Parameters Total NbO TiO Sc Example Block Model Mass 100 t Example Block Model Grades 100 t 0.70% 2.50% 60 ppm Metallurgical Recoveries 86.72% 83.65% 92% Amount Payable 100.0% 100% 100.0% Conversions from input grade to product 69.6% 235.0% 153.4% Refining Charges 0 0 0 Price US$ 52/kg US$ 1.86/kg US$ 2,000/kg Calculate Contained Metal Nb2O5 TiO2 Sc 100 t 700 kg 2,500 kg 6 kg Calculate Saleable Metal (conversion to product, discounted by recovery) 100 t 8.45 kg Nb 424.3 kg FeNb 653 kg TiO2 4,914.6 kg Sc (as Sc2O3) Calculate Block Dollar Value for Each Metal FeNb TiO2 Sc 100 t US$ 22,065 US$ 9,141 US$ 16,891 2 5 2 (1) (2)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 149 | Page Total Block Value Block Value per tonne US$ 48,097 US$ 480.97/t Source: DGC 2026 1. Stored as PPM in the block model. Sc % = Sc ppm/10,000. 2. Overall metallurgical recovery, including all losses Figure 12‐3 through Figure 12‐6 provide a grade-tonne curve for the deposit using various NSR cut- off grades, (CoG). It includes only Proven and Probable material and shows average grades for each grade variable. All Inferred material is treated as having a zero-grade value in this mineral reserve estimation. img170397038_79.jpg Source: Amplify Mine Planning, 2026 Figure 12‐3:NioCorp Grade (Nb2O5)-Tonne Curves Based on NSR Cut-Off
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 150 | Page Source: Amplify Mine Planning, 2026 Figure 12‐4:NioCorp Grade/Tonne Curves Based on NSR Cut-Off (TiO2) Source: Amplify Mine Planning, 2026 Figure 12‐5:NioCorp Grade (Sc ppm) – Grade Tonne Curves Based on NSR Cut-Off
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 151 | Page Source: Amplify Mine Planning, 2026 Figure 12‐6: NioCorp Grade (TREO %) – Grade Tonne Curves Based on NSR Cut-Off To establish the initial boundary of the mine design and to assure inclusion of all potential Mineral Reserves, a minimum CoG of US$218/ton was used based on the estimated costs shown in Table 12‐4. Table 12‐4: Operating Costs Used for Mine Design NSR Cut-off Category 2024 BOD Model Mining Cost $50.86 $46.14 Processing $137.83 $125.04 Water Management and Infrastructure $18.28 $16.58 Tailings Management $2.21 $2.00 Other Infrastructure $6.02 $5.46 General and Administrative $9.80 $8.89 Royalties / Annual Bond Premium $9.17 $8.32 Other Costs $6.92 $6.28 Total Cost $241.09 $218.71 (US$/tonne mined) (US$/ton mined) Source: NioCorp, 2025 Notes:
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 152 | Page (1) Includes backfill. (2) Values used here differ from the economic model generated from the final overall site design. NioCorp, Dumas, and Amplify are satisfied that the values used were applicable to establishing the correct and optimum mining design. 12.2.4 Mine Design Potential mining areas were identified using stope optimization within Deswik.SO StopeOptimizer© software. The stope optimizer output was reviewed on a level-by-level basis, and a 3D mine design was generated. The estimated cut-off NSR value (CoNSR) of US$ 218/ton provided by NioCorp was used as a starting point for this analysis. Generally, stopes would be selected based on the minimum CoG or CoNSR. However, as the CoNSR value is much lower than the resulting average stope NSR value, the CoNSR was not the decisive factor in the stope optimization process. Rather than using only a minimum CoNSR, the mine design also targeted an average cut-off Nb2O5 grade of 0.65% and targeted higher annual ferroniobium production during the first five years of production. With a milling constraint of 3,047 tpd, the steady-state life of mine average annual ferroniobium production during full production years was 8,282 tons annually. This strategy results in a LOM NSR average value of US$ 590.84/ton. The identified mining blocks provide an approximate 43-year LOM. The design includes stopes, development accesses, and necessary infrastructure. Figure 12‐7 shows the current mine design. Source: Amplify Mine Planning, 2026 Figure 12‐7:Current Mine Design 12.3 R ESERVES The 2026 Mineral Reserves were classified in accordance with Regulation S-K 1300. More specifically, the 2026 Mineral Reserves were classified using the guidelines developed by the Committee for Mineral Reserves International Reporting Standards (CRIRSCO) released in 2013 and adopted for the United States by the Society for Mining, Metallurgy and Exploration (SME) in 2017. Measured and Indicated Mineral Resources were converted to Proven and Probable Mineral
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 153 | Page Reserves by applying the appropriate modifying factors, as described earlier in this section, to potential mining block shapes created during the mine design process. The underground mine design process resulted in a mine plan with an in-situ Mineral Reserve Estimate of 45.9 Mt (diluted) with an average grade of 0.76% Nb2O5, 2.68% TiO2, 69.3 ppm Sc, and 0.34% TREO. This estimate is based on a mine design using elevated CoGs and applying the US$ 218/t NSR CoG to capture all potential Mineral Reserves within the design and an average cut-off grade of 0.650% Nb2O5. These numbers include a 95% mining ore recovery to the designed wireframes (sill pillar recovery is 62.5%) in addition to applying approximately 6% - 9% unplanned dilution as described in Section 12.2.1. Table 12‐5 summarizes the underground reserves as of June 30, 2026. Table 12‐5: In-situ Underground Mineral Reserves Estimate for Elk Creek, Effective Date June 30, 2026 2026 Reserve Mineral Reserve Classification Cut-off NSR Tonnage Grade Grade Grade Grade (US$/ton) (ton) (NbO%) (TiO%) (Sc ppm) (TREO %) Proven 218 7,570,098 0.760 2.70 71.5 0.32 Probable 218 38,359,365 0.759 2.67 68.8 0.35 Total 218 45,929,462 0.759 2.68 69.3 0.34 Classification Tonnage (ton) NbO Grade (%) FeNb (ton) Payable Nb (ton) TiO G rade (%) Payable TiCl (ton) Sc Grade (ppm) Payable ScO (ton) TREO Grade (ppm) Payable TREO (ton) Proven 7,570,098 0.76 53,651 34,873 2.70 405,938 71.5 762 3,232 22,509 Probable 38,359,365 0.76 271,386 176,401 2.67 2,036,334 68.8 3,717 3,489 123,115 Total 45,929,462 0.76 325,038 211,274 2.68 2,442,272 69.3 4,479 3,446 145,625 Source: Amplify Mine Planning, 2026. Notes: (1) All figures are rounded to reflect the accuracy of the estimates. Totals may not sum due to rounding. (2) The Qualified Person for the Mineral Reserve estimate is Amplify Mine Planning LLC. The estimate has an effective date of June 30, 2026. (3) The Mineral Reserve is based on the mine design and mine plan, utilizing an average cut-off grade of 0.650% Nb2O5 with an NSR of US$ 218/ton. (4) The estimate of Mineral Reserves may be materially affected by metal prices, environmental, permitting, legal, title, taxation, socio-political, marketing, infrastructure development, or other relevant issues. (5) Annual life of mine (LOM) average production rate of ~8,282 tons of FeNb/annum in the years of full production, (6) Mining dilution of ~6% was applied to all stopes and development, based on 3% for the primary stopes, 9% for the secondary stopes, and 5% for ore development. (7) Mining recoveries of 95% were applied in longhole stopes and 62.5% in sill pillar stopes. (8) Price assumptions for FeNb, Sc2O3, TiO2 and TREO metals are based upon independent market analyses for each product. (9) Price and cost assumptions are based on the pricing of products at the “mine- gate,” with no additional down-stream costs required. The assumed products are a ferroniobium product (metallic alloy shots consisting of 65%Nb and 35% Fe), titanium in the form of TiCl4, scandium trioxide in powder form and rare earth oxides in either purified oxide or carbonate form. The Mineral Reserve has an average LOM NSR of US$590.84/ton. (10) The economic assumptions used to define Mineral Reserve cut-off grade are as follows: 2 5 2 2 5 2 4 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 154 | Page Parameter Value Unit Mining Cost 46.14 US$/ton mined Processing 125.04 US$/ton mined Water Management and Infrastructure 16.58 US$/ton mined Tailings Management 2.00 US$/ton mined Other Infrastructure 5.46 US$/ton mined General and Administrative 8.89 US$/ton mined Royalties/Annual Bond Premium 8.32 US$/ton mined Other Costs 6.28 US$/ton mined Total Cost 218.71 US$/ton mined NbO to Niobium conversion 69.9 % Niobium Process Recovery 86.72 % Niobium Price 23.59 US$/lb TiCl Process Recovery 83.65 % TiCl Price 0.84 US$/lb Sc Process Recovery 92 % Sc to ScO conversion 153.4 % Sc Price 891.76 US$/lb DyO Process Recovery 92 % DyO Price 185.97 US$/lb NdO Process Recovery 92 % NdO Price 56.70 US$/lb PrO Process Recovery 92 % PrOPrice 56.70 US$/lb TbO Process Recovery 92 % TbO Price 836.88 US$/lb 12.4 R ELEVANT F ACTORS It is Amplify Mine Planning LLC’s opinion that there are no known environmental, permitting, legal, socio-economic, marketing, political, or other factors which could materially affect the underground Mineral Reserve Estimate. In addition, realistic and justifiable mining factors were used in determining the mine plan and schedule for reporting mineral reserves. These factors include geotechnical considerations, ore loss, dilution, mine extraction rates and metallurgical recovery. The pricing for Niobium, Scandium, Titanium and Rare Earths used to support the Mineral Reserve estimate was based on third party market reports described in Section 16.1. It is Amplify Mine Planning LLC’s opinion that the pricing used is adequate and appropriate for use in estimating Mineral Reserves. Further details on the market assumptions and timeframes analyzed are disclosed in Chapter 16 of this report. 2 5 4 4 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 155 | Page 13 M INING M ETHODS 13.1 G EOLOGY O VERVIEW The mine planning work is based on the resource geology and block model, described in Section 11 of this Technical Report Summary. In addition to the mineralization, various other elements were estimated into the model for metallurgical purpose. 13.2 R OCK E NGINEERING This section presents the rock mass characterization work (Section 13.2.1) and the associated rock engineering aspects of the project (Section 13.2.2). 13.2.1 Geomechanical Appraisal This section is summarized from the rock mass characterization report completed in support of the mine design (A2GC, 2026a). 13.2.1.1 Available Geomechanical Data The rock mass characterization is based on the following data sources: • Geomechanical core logging, which includes the description of the core intervals (RQD, strength, etc.) and the condition of every open joint. From this dataset, the rock mass can be classified according to the Q-system (Barton et al., 1974; NGI, 2022). • Televiewer surveys from which the orientation of the structures in the drill core is obtained from measured alpha and beta angles. • Laboratory intact rock strength testing from which intact rock strength parameters are derived. A supplemental geomechanical drilling and strength testing program was conducted in 2025 to improve the geomechanical domains grouping. The available geomechanical data from drill holes are summarized in Table 13‐1. Table 13‐1: Summary of available geomechanical data from drill holes for the Elk Creek Project Type of data 2011 Investigation 2014 Investigation 2015 Investigation 2025 Investigation Drillholes with RQD data only5,005 ft (1,525 m) (3 holes) 4,920 ft (1,500 m) (3 holes) 3,555 ft (1,083 m) (2 holes) 23,550 ft (7,178 m) (11 holes) Complete geomechanical core logging (with joints description)- 36510 ft (11,128 m) (16 holes) 2505 ft (763 m) (2 holes) 13,115 ft (3,998 m) (6 holes) Televiewer surveys - 19,869 picks 13,454 open joints (13 holes) 2,236 picks 1,237 open joints (2 holes) 3,704 picks 554 open joints (9 holes) Laboratory testing - 31 UCS tests 40 UCSE tests 17 TCS tests 12 BTS tests 0 UCS tests 18 UCSE tests 54 TCS tests 35 BTS tests Source: A2GC, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 156 | Page Notes: (1) UCS = Unconfined compressive strength. (2) UCSE = Unconfined compressive strength with measurements of elastic properties. (3) TCS = Confined triaxial compressive strength. (4) BTS = Indirect splitting tensile strength (Brazilian test). 13.2.1.2 Data Gaps The amount, coverage and quality of data are sufficient for this level of study. • The orebody has good coverage from the geomechanical drillholes, including at depth. • The domaining approach is acceptable. • The joint sets interpretation is suitable for this stage of the project development, with Televiewer surveys having been conducted in several orientations to reduce the bias due to blind zones. • The fitting of the intact rock strength envelopes is satisfactory for most geomechanical domains. • Local stress measurements have been conducted. However, the following data gaps are identified: • There are no underground mapping data, as would be expected for a project that has not been developed. • The presence, location and extent of degraded rock mass quality areas are not well known, although modeling efforts were made to improve the current understanding. • Results from local stress measurements show some variability in both magnitude and orientation. • Some geomechanical domains have insufficient strength testing data. The datasets for elastic properties are relatively small (five data points or less). To address the above data gaps, the following supplemental data collection is recommended: • As underground development starts, underground mapping should be conducted as soon as possible to confirm rock mass conditions and joint sets orientation. • The presence, location and rock mass conditions of the degraded rock mass quality areas should be investigated. As such, it will be important to validate the location and thickness of the interpreted property-scale structures. A better definition and 3D understanding of the zones with lower quality (weathered areas) is needed for detailed and reliable planning of the stoping area. • As underground development progresses, field observations should be conducted to validate the measured stress field. This is done by observing the location of shear failure around the perimeter of isolated horizontal and vertical development and deducing the stress field orientation with respect to their orientation. If discrepancies are observed, supplemental in situ stress measurements should be conducted at several depths to constrain the pre-mining stress regime.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 157 | Page • Additional strength testing data should be conducted in the weathered lamprophyre, weathered carbonatite and weathered mineralized domains. Supplemental elastic properties testing in all domains would increase the confidence in the dataset. 13.2.1.3 In-Situ Stress Conditions Stress measurements were conducted by Agapito Associates Inc. (Agapito) at Elk Creek in Fall 2014. Measurements were done using the Sigra over-coring stress test tool. This technique enables a calculation of the magnitudes and orientation of the principal stresses in the plane perpendicular to the borehole axis. Testing was conducted between 425 ft (130 m) and 2,180 ft (665 m) below surface. A total of thirteen (13) tests were attempted, yielding eight successful tests. Table 13‐2 summarizes the in-situ stress tensor considered for the Project, based on the stress testing results. Table 13‐2: In-situ stress conditions considered for the Elk Creek Project Principal stress component Orientation (dip/azimuth) Magnitude (MPa) Major principal stress σ 00° / 072° 0.036 z Where z is the depth in meters Intermediate principal stress σ = σ 90° / 000° 0.029 z Minor principal stress σ 00° / 162° 0.021 z Source: A2GC, 2026 13.2.1.4 Rock Mass Geomechanical Domains For the purpose of geomechanical analyses and designs, the rock mass volume is typically divided into geomechanical domains with similar geological, structural and rock parameter characteristics. The domaining approach was refined based on the updated geological model, on the logged rock weathering index and on the geomechanical data collected in the 2025 investigation campaign. The Elk Creek deposit is contained within carbonate rocks whose boundary lies well beyond the property. The carbonates are generally strong, hard and brittle rock masses, sparsely jointed to blocky. They are very heterogenous in nature exhibiting numerous macro and micro defects and frequent lithological changes. The initial domaining approach grouped all lithologies within the hanging wall, footwall and mineralized rocks into three (3) geomechanical domains. Some areas within the carbonate rocks with significantly lower rock mass quality have been identified (higher degree of fracturing, higher degree of rock alteration); these areas are referred to as weathered areas (their logged weathering index in the drillhole database is usually high). A concentration of weathered rock was identified to the west of the orebody and hanging wall, but there are also other areas to the east. A conceptual weathering model was built and used to guide the geomechanical domaining approach. The carbonate rocks are overlain by Pennsylvanian sedimentary rocks. Those exhibit various intensities of foliation, this foliation being generally sub-horizontal. The contact between the Pennsylvanian sediments and the carbonate rocks is generally weathered over several meters. Seven (7) geomechanical domains are considered for the Elk Creek project: 1 2 v 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 158 | Page (1) Pennsylvanian sediments: limestone, mudstone and, to a lesser extent, sandstone found in the first 820 ft (250 m) (shallowest) (2) Carbonatite: rock forming the main orebody with a dominant carbonatite composition (3) Weathered carbonatite: pockets of carbonatite exhibiting significantly degraded rock mass quality (4) Lamprophyre: rock forming the main orebody with a dominant lamprophyre composition (5) Weathered lamprophyre: pockets of lamprophyre exhibiting significantly degraded rock mass quality (6) Mineralized domain: carbonatite identified as being mineralized (7) Weathered mineralized domain: pockets of mineralized carbonatite exhibiting significantly degraded rock mass quality 13.2.1.5 Intact Rock Properties Intact rock strength was evaluated with laboratory strength tests on selected samples. Unconfined compressive strength tests with and without measurements of elasticity parameters (UCSE and UCS, respectively), Brazilian tensile strength tests (BTS) and triaxial compressive strength tests (BTS) were conducted. The number of valid intact rock strength laboratory tests per geomechanical domain used to establish intact rock strength envelopes is given in Table 13‐3. Table 13‐3: Number of valid intact rock strength laboratory tests per geomechanical domain used to establish intact rock strength envelopes. Lithology Unit UCSE UCS Triaxial Brazilian Total Sediments 20 6 14 13 53 Carbonatite 5 3 14 11 33 Weathered carbonatite 7 3 7 — 17 Mineralized 8 13 20 12 53 Weathered mineralized 5 2 2 3 12 Lamprophyre 10 2 12 7 31 Weathered lamprophyre 1 — 1 — 2 Total 56 29 70 46 201 Source: A2GC 2026 Hoek-Brown intact rock strength envelopes (Hoek, 1994) were obtained for each geomechanical domain by Bayesian fit through the selected datapoints. The intact rock mechanical properties per geomechanical domain are shown in Table 13‐4. Tests that have failed along a pre-existing discontinuity were excluded from the analysis. Table 13‐4: Summary of intact rock mechanical properties per geomechanical domain. Geomechanical domainUCS BTS E 𝜈 Density 𝜎 m Sediments 10,890 psi (73 MPa) 770 psi (5.3 MPa) 3.63 Mpsi (25 GPa) 0.29 156.1 lb/ft3 (2,500 kg/m3) 10,010 psi (69 MPa) 16.5 Carbonatite 17,985 psi (124 MPa) 1,405 psi (9.7 MPa) 11.02 Mpsi (76 GPa) 0.30 181.7 lb/ft3 (2,910 kg/m3) 21,900 psi (151 MPa) 21.1 (1) (2) (3) (4) ci (5) i (5)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 159 | Page Geomechanical domainUCS BTS E 𝜈 Density 𝜎 m Weathered carbonatite6,235 psi (43 MPa) - 7.54 Mpsi (52 GPa) 0.25 176.7 lb/ft3 (2,830 kg/m3) 15,665 psi (108 MPa) 19.7 Mineralized 23,785 psi (164 MPa) 1,350 psi (9.3 MPa) 10.88 Mpsi (75 GPa)* 0.28* 189.8 lb/ft3 (3,040 kg/m3) 23,060 psi (159 MPa) 19.9 Weathered mineralized20,885 psi (144 MPa) 710 psi (4.9 MPa) 10.44 Mpsi (72 GPa) 0.28 181.7 lb/ft3 (2,910 kg/m3) 15,665 psi (108 MPa) 26.3 Lamprophyre 21,755 psi (150 MPa) 1,365 psi (9.4 MPa) 9.28 Mpsi (64 GPa) 0.29 180.4 lb/ft3 (2,890 kg/m3) 16,680 psi (115 MPa) 15.1 Weathered lamprophyre28,570 psi (197 MPa)* - 7.69 Mpsi (53 GPa)* 0.29* 172.3 lb/ft3 (2,760 kg/m3) 11,315 psi (78 MPa) 14.0 Notes: (1) unconfined compressive strength (2) indirect splitting tensile strength (Brazilian Tensile Strength tests) (3) Young’s modulus (4) Poisson’s ratio (5) sci, mi: Hoek-Brown parameters * only one sample available 13.2.1.6 Property-Scale Structures Property-scale structures were interpreted by SRK in 2016 based on drillcore data (RQD and lithological information) and the Televiewer orientation dataset. A total of 31 structures have been identified. Based on the evidence of structures being crossed in the drillcore, this model seems to be generally concordant (although some depth mismatches were observed). Conversely, many features crossed in the drillcore are not captured at the scale of this structural model. As underground development progresses, the presence, location and extent of the property-scale structures should be confirmed. 13.2.1.7 Rock Mass Jointing For joint sets interpretation, the carbonatite, mineralized, and lamprophyre (weathered and unweathered) geomechanical domains were grouped. The resulting sub-dataset is referred to as the carbonatite structural domain. The Pennsylvanian sediments constitute the second and distinct structural domain. The orientation of the mean joint sets is provided in Table 13‐5, per structural domain. The stereonets are shown in Figure 13‐1. The stereonets are shown in Figure 13‐1. The Televiewer dataset shows high variability, reflecting the heterogeneous nature of the rock mass. In the carbonatite, joint set 1 is major and apparently more related to fracturing. Joint set 2, more related to foliation and contacts, also seems to be major but is more randomly distributed. Joint sets 3 and 4 are minor and could be seen more as areas on the stereonet where there are many random joints. In the sediments, the dominant structural trend is sub-horizontal and related to their foliated nature. Some sub-vertical joints have also been logged. Their orientation trend is reported, although minor compared to that of the sub-horizontal set that remains the main driver. (1) (2) (3) (4) ci (5) i (5)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 160 | Page Table 13‐5: Summary of mean joint set orientations per structural domain Structural DomainSet Area definition on stereonet Average within the area Carbonatite 1 Cone Dip: 70° Dip direction: 155° Cone angle: 33° Dip: 69° Dip direction: 155° 2 Cone Dip: 28° Dip direction: 063° Cone angle: 40° Dip: 29° Dip direction: 065° 3 Window Dip: 55 to 95° Dip direction: 190° to 260° Dip: 75° Dip direction: 220° 4 Window Dip: 50 to 80° Dip direction: 320° to 030° Dip: 64° Dip direction: 357° Sediments H Cone Dip: 00° Dip direction: 155° Cone angle: 30° Dip: 01° Dip direction:268° 1 Window Dip: 72 to 102° Dip direction: 125° to 175° Dip: 87° Dip direction: 148° Notes: (1) Dip is measured downwards from horizontal and varies between 00° (horizontal) and 90º (vertical). Values greater than 90° indicate that the window continues on the other side of the stereonet. (2) Dip direction varies clockwise from north (North is 000°, East is 090°, South is 180° and West is 270º). Carbonatite Sediments Source: A2GC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 161 | Page Figure 13‐1:Lower hemisphere equal angle plots showing the structural data and joint sets interpretation per structural domain 13.2.1.8 Rock Mass Classification Geomechanical core logging data were processed according to the Q-system (Barton et al., 1974; Grimstad & Barton, 2014; NGI, 2022). Rock mass quality has been assessed by geomechanical domain. The Pennsylvanian sediments, carbonatite, lamprophyre and mineralized domains are classified as ‘Good’ quality rock masses quality rock masses in the Q-system (30th percentiles and median values between 10 and 40). The weathered rock masses are classified as Fair in the Q-system (30th percentiles and median values between 4 and 10). The rock mass classification results are provided in Table 13‐6 in terms of 10th, 30th and 50th percentile of the distribution of the ratings weighted per drill hole interval length. These percentiles, which can be considered on the conservative side, are commonly used for projects at this level of study. It should be pointed out that the RQD values of the entire dataset are variable, with very high and very low values (8% of the drilling intervals logged in geomechanical drillholes have a RQD value lower than 25%). This is in accordance with the general rock mass aspect. Table 13‐6: Summary of rock mass classification per geomechanical domain Geomechanical domain Q’-system 10 percentile 30 percentile 50 percentile Sediments 12 33 50 Carbonatite 3.5 12.8 25 Weathered carbonatite 2.0 4.6 7.3 Mineralized 4.3 9.8 18 Weathered mineralized 2.1 6.7 12.4 Lamprophyre 8.2 24 47 Weathered lamprophyre 1.6 4.8 7.4 Source: A2GC 2026 Notes: (1) *Assuming dry conditions and excluding the influence of active stresses (excluding the Jw and SRF factors). 13.2.1.9 Anticipated Rock Mass Behaviour The anticipated rock mass behaviour can be differentiated into the following main categories: • From surface to approximately 2135 ft (650 m) in depth (approximately 58% of the project tonnage, between levels L250 and L650): o Due to the low stress conditions, the rock mass behaviour around the openings is expected to be largely structurally controlled and influenced mainly by the occurrence, spacing, persistence and characteristics of the natural discontinuities, as well as their intersections. o The ground instabilities in stopes and around development is anticipated to be controlled by the relaxation of the jointed rock mass, which could result in gravity-driven wedge instabilities. * th th th
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 162 | Page o Due to relaxation, the dilution off the stope walls can be expected to be particularly sensitive to the length of time the stopes will remain open and the rock mass damage originating from drilling and blasting practices. o Minimum to no rock mass damage due to the induced stresses is expected to occur around typical stopes in this depth range, except in sectors of lower rock mass quality, for example in shallow stopes close to the Pennsylvanian contact. • From 2135 ft (650 m) to 3280 ft (1,000 m) in depth (approximately 42% of the project tonnage, between levels L650 and L930): o This depth range will constitute a transition between mainly relaxation-induced instabilities to stress damage-driven instabilities. The former are structurally controlled whereas the latter are controlled by the strength of the rock and healed discontinuities (such as veins). • With increasing depth, development could sustain some stress-induced damage near the mining fronts where stresses concentrate ahead of mining. The high stress front can be expected to concentrate close to the excavations (i.e., typically one stope strike length ahead and within the same retreating panel). Its intensity will increase with depth. • Higher stress mining fronts are expected only in lead primary stopes and the first panels in the secondary stopes. The second, third and beyond panels are anticipated to be in the stress shadow (i.e., in deconfined ground), even at depth. • Sill pillar levels (approximately 14% of the project tonnage) o Sill pillar levels are created where mining fronts will merge (vertically). The following levels are concerned: L490 and L690. The bottom-up sequence will push ground stresses upwards and concentrate them in sill pillars. Stress concentration increases should start to be tangible in the L690 sill pillar. Stress concentration on sill levels is anticipated to lead to spalling and local instabilities, as well as slippage and deformation along geological discontinuities. No rock bursting conditions are expected largely because all stopes are shallower than 3,280 ft (1,000 m). Some operational challenges are likely to be encountered during the mining of sill pillar stopes at depth, particularly in the lead stopes. • Poor rock-mass quality areas (evaluated at 15% of the project tonnage): o The rock mass in the vicinity of the interpreted property-scale faults is expected to be of lower quality. Areas of weathered rock mass have also been identified. Stopes located in and close to these areas can be expected to produce higher levels of dilution and require additional ground support. o Areas of poor rock mass quality could provide conduits for water infiltration into mine workings. FLAC3D numerical simulations did not consider hydrogeological effects. • The main joint set orientations are expected to be highly variable throughout the deposit. The geometry of gravity-driven wedge instabilities is thus anticipated to vary throughout the mine. At the scale of a drift, the large variability and complexity of the rock mass jointing is anticipated to result in variable conditions in terms of wedge instabilities.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 163 | Page Development crossing property-scale structures will encounter lower rock mass quality and unraveling conditions. Other small-scale faults and geological features can also be expected to influence the rock mass behaviour locally. Note that the mining sequence is planned to be progressing from the center of a horizon towards the abutments (i.e., there are no converging mining fronts within a horizon) to manage mining-induced stresses. 13.2.2 Geomechanical Guidelines for Mine Design The geomechanical recommendations and guidelines presented below are based on geomechanical assessments that included empirical methods (stope dimensions, dilution estimates, backfill strength requirements) and mine-wide numerical simulations of the mining sequence with the advanced explicit three-dimensional finite-difference code for continuum mechanics engineering applications FLAC3DTM (Itasca, 2019). This section is summarized from the rock engineering study completed in support of the mine design (A2GC, 2026b). The rock engineering study was completed based on the life of mine stope layout and mining sequence dated March 13, 2026. 13.2.2.1 Stope Dimensions and Dilution Estimates The planned mining method is transverse longhole open stoping. The stopes are planned to be backfilled with cemented paste backfill. Stope dimensions were first established for the individual stopes to be stable according to the empirical Stability Graph method (Mathews et al., 1980; Nickson, 1992; Potvin, 1988), amongst others) and to have an external dilution of less than 3 ft (1.0 m) according to the equivalent linear overbreak/slough (“ELOS”) empirical method (Clark, 1998). These dimensions were later tested with the numerical modelling analyses. The stope dimensions considered for the economic evaluation of the deposit are: • Vertical height between levels (floor-to-floor): 130 ft (40 mH) • Panel width (transversally, east-west): 50 ft (15 mW). • Maximum stope strike length (longitudinally, north-south): 50 ft (15 mL). Following the numerical analyses – where local stress magnitudes, lithology effects and the interaction between stopes were examined more explicitly – the empirical ELOS estimates (i.e., less than 3 ft (1 m)) were maintained. The two main numerical assessment criteria to estimate dilution were the plastic state of the rock mass and its confinement level (minimum principal stress magnitude). Little rock mass failure is predicted from the numerical analyses, confirming the limited potential for dilution. However, in the weathered areas, estimated to represent about 15% of the production stopes, higher dilution is anticipated (up to 3 ft (1.0 m) or even 7 ft (2.0 m) in some cases). In the end, an average ELOS of 6% in primary stopes and 9% in secondary stopes was considered in the economic evaluation of the deposit. For 50 ft-long (15 m-long) and wide stopes, this corresponds to 3.0 ft (0.90 m) and 4.4 ft (1.35 m), respectively, and is a conservative estimate. These analyses are dependent on the pre-mining stress regime (orientation and magnitude). As stress data and observations become available and as mining experience is gained, the pre-mining stress regime should be confirmed. If the maximum principal stress magnitude is higher than anticipated, the potential for dilution could be higher. Conversely, if the maximum principal stress
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 164 | Page orientation shows evidence of being more parallel to the orebody strike rather than perpendicular to it (as assumed), the potential for dilution could be lower. Stope dimensions being an important control to reduce the potential for dilution, efficient mitigation measures should also be implemented and maintained during production, including the following: • Good blasting techniques, in terms of design and QA/QC. In particular, blasthole accuracy will be critical as any loaded blasthole deviating into a stope wall will immediately cause significant dilution; • Quick mucking following blasting; and, • Prompt backfilling, to further minimize the amount of time stopes will remain open. 13.2.2.2 Dimension of Pillars Sill Pillar Mining Two sill pillars will be created in the mining sequence (on levels L490 and L690). These sill pillars are planned to be extracted during the mining sequence. The thickness of the sill pillars is planned to be 131 ft (40 m) (similar to the rest of the stopes). The anticipated stress conditions in the sill pillars were assessed based on numerical modelling results. The main assessment criterion was the pre-mining stress magnitude: the more stresses accumulate in a sill pillar prior to mining, the more operational challenges can be expected during its recovery. None of the sill pillars are forecasted to yield (fail) prior to mining. Operational challenges due to mining in highly stressed ground are expected for the lead stopes of the first panel to be mined in the sill pillars at L690. To reflect the operational rock mechanics-related challenges anticipated during mining of the sill pillars, a 62.5% estimated recovery was applied to all sill pillars. Increasing stoping cycle time (by 60-75% of the normal mining rate) and/or adding rehabilitation costs and delays could also be considered for the deeper sill pillar. Waste Rib Pillars Rib pillars are not planned to be left in place as part of the selected mining method. However, waste rib pillars could be left in place when the mineralization is not continuous. Some instances of waste rib pillars were present in the proposed stope layout. Such pillars should maintain at least a 1:1 aspect ratio, i.e., maintain the rib pillar strike length equal to, or longer than, the diluted horizontal width of the widest abutting stope. At depth, it would be preferable to systematically mine small rib pillars (with an aspect ratio less than 1:1) to avoid stress concentration and seismicity related issues. Waste rib pillars at depth with an aspect ratio up to 2:1 may benefit from their own specific stability analyses. Crown Pillar The orebody being contained within the carbonate rocks beneath the 820-ft (250-m) thick Pennsylvanian sediments, there is no crown pillar as such in the Elk Creek Project.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 165 | Page 13.2.2.3 Backfill Strength Requirement The production stopes will be backfilled with cemented paste backfill. Minimum backfill strength requirements were estimated for longitudinal mining using various common backfill limit equilibrium stability methods, namely the Mitchell (1982), and Li & Aubertin (2012 and 2014) approaches. In all cases the exposed backfill height was 130 ft (40 m), the backfill had a density of 137.3 lb/ft3 (2200 kg/m3) and a friction angle of 30° was considered, along with a factor of safety of 1.5. Based on the range of results provided by these methods, the A2GC recommendation is to maintain a minimum backfill UCS of 60 psi (400 kPa). In addition to ensuring self-standing exposed paste walls, this strength value would also prevent liquefaction triggered by nearby blasting. Note that stopes sitting immediately above sill pillar stopes will require higher backfill strength as they will be undercut during sill mining. For these stopes the minimum UCS required is in the 75 to 145 psi (0.5 to 1.0 MPa) range, depending on geometry and to be confirmed by site-specific analyses. The higher strength will also be beneficial to reduce backfill dilution from blasting. 13.2.2.4 Seismic Conditions Considering that: • Most of the mining will occur at a depth of less than 1475 ft (450 m) for the first years; • The mining sequence does not create converging pillars (except for the sill pillars); • The footprint of the orebody is not overly large (strike length less than 2295 ft (700 m) and at most 330 ft (100 m) wide); and, • The rock mass is generally not overly stiff, strong and brittle. Problematic seismicity is not anticipated early in the mine life. Therefore, there is no stringent need to install a seismic system at the very start of the project. However, it will be important to closely monitor any signs of seismicity reported by the operations as the mine deepens. Typically, and as the numerical modelling analyses also suggest, seismic conditions could develop starting at a depth of around 2135 ft (650 m) in sill pillar stopes and will further increase with depth, and particularly in the lead stopes. If such signs start to appear, then a sufficiently sensitive and accurate seismic monitoring system should be promptly installed, and related triggered action response plans (TARPs) developed and implemented. The costing of the installation of a microseismic monitoring system that would be installed at some point in the life of mine (sometime during the first few years so that reliable background seismic levels can be established), should be considered in future financial forecasts, especially if there is a potential to extend the mine deeper than the maximum depth considered in the current study. 13.2.2.5 Infrastructure Proximity Relative to Ore Body Fixed infrastructure proposed locations were assessed based on numerical stress modelling results. The infrastructures and development were not explicitly included in the simulations at this stage and therefore the modelling results do not take into account the stress redistributions due to the presence of all future underground openings. The main assessment criteria were the variation of stress due to mining, the loss of confinement and the stress increase (relative to the strength of the intact rock) at the proposed underground infrastructure locations, but at this stage without physically including these excavations in the model.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 166 | Page The assessed infrastructures include: • Ramps • Levels accesses and main level drives (longitudinally following the orebody) • Ventilation raises (two segments in the first mining horizon only) • Ore passes (one for each mining horizon) • Underground shops (located on levels L450 and L650) Based on the numerical modelling results and a general review of the currently planned infrastructure locations, the following were concluded. • The ramps are located within the area affected by mining (from a stress change perspective) but are not expected to be subjected to stress-induced damage (no excessive stress variation is anticipated). • The level accesses, linking the ramps to the level main drives, hence transitioning from a low mining-induced stress change area to closer to the mining area, will experience stress changes as they get nearer the orebody. Based on the modelling results, the level accesses in the analysed layout are not expected to experience excessive stress changes. • Main level drives are expected to be subjected to some stress-induced damage, particularly at depths below 1870 ft (570 m) (L570 and deeper). This has been taken into account in the ground support requirements (rehabilitation anticipated at least once or twice during the life-of-mine). • The ventilation raises, the ore passes and the underground shops are located within areas affected by mining but are not expected to be subjected to stress-induced damage. 13.2.2.6 Ground Support Ground support requirements were derived with both empirical guidelines and limit equilibrium gravity driven wedge analyses. They were derived for costing purposes, based on current data and their interpretation, the assessments performed and A2GC’s experience. Ground support consists of various combinations of rebar bolts, friction sets, cable bolts, mesh screen and shotcrete. Support was selected based on several parameters including excavation size, location and planned service time, local geology, mining- induced stress changes, as well as other factors that could affect its performance. A high-level summary of the ground support recommendations is given hereafter. Please refer to A2GC, 2026b for accompanying notes and details (e.g., length of ground support elements, spacing and pattern). • Ramp and other permanent infrastructures such as level accesses: rebar bolts in the back and in the walls, with mesh screen • In adverse conditions, a layer of shotcrete is to be added, and Swellex may replace the rebar bolts for easier installation. This is considered for 30% to 50% and 15% to 40% of the Sediment and Carbonatite rock units, respectively.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 167 | Page • For best practice, development faces should be supported with friction bolts and mesh screen. • Ore drives: Swellex bolts in the back and SplitSets in the walls, with mesh screen. • Intersections: secondary support added in the back (resin-grouted threaded bar bolts, or tensioned-plated single- strand plain cablebolts). • Permanent stationary infrastructures (refuges, parking areas, garages, shops): rebar bolts in the back and in the walls, with mesh screen, and secondary support in the back (resin-grouted threaded bar bolts, or tensioned- plated single-strand plain cablebolts) with shotcrete. • Vertical raises: rebar bolts in the walls, with mesh screen and possibly a shotcrete layer, depending on conditions. Note that ore passes and inter-level ventilation raises with no man entry can be left unsupported if in good ground. • Stopes: tensioned-plated single-strand plain cablebolts in the back • For cost estimation purposes, this recommendation should be applied to about 20% of primary stopes and up to 60% of secondary stopes in unweathered rock. • Stopes in adverse conditions (about 15% of the stopes) can be expected to require additional cablebolting. • Cablebolts should also be installed in the face for the first stope in sequence. • All stopes will be paste backfilled. • Surface boxcut excavation (under construction at the time of writing): rebar bolts in the face and in the walls, with mesh screen and shotcrete. • Mine portal (under construction at the time of writing): rebar bolts with mesh straps and shotcrete in the back and walls in the first 32.8 feet (10 meters) of the ramp. Mesh straps across the brow. The ground support needs should be reassessed once the rock mass conditions and behaviour are confirmed once underground access becomes available. Changes in ground conditions will need to be monitored and ground support modified accordingly. 13.3 H YDROGEOLOGY D ESIGN P ARAMETERS The hydrogeology of the deposit was characterized based on four phases of work: Phase I: The first phase of hydrogeological characterization was conducted during Phases 1 and 2 of the core drilling program and consisted of packer testing, installation of piezometers, and measurement of water levels (SRK, 2017). Specifically, the program included: • 42 downhole packer-isolated injection and airlift tests in drill holes.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 168 | Page • Installation of six 2“ PVC standpipe piezometers isolated in the carbonatite and open to large intervals of the deposit. • Installation of two nominal 2“ PVC standpipe piezometers isolated in the 600 ft thick Pennsylvanian aquitard above the carbonatite. • Frequent measurement of water levels in open drill holes and piezometers over a period of six months. Phase 2: Following the second phase of resource-related core drilling, a 10-day airlift pumping test was completed using a deep, open, vertical PQ drill hole as a pumping well (SRK, 2017). Water levels from the surrounding piezometers were recorded over the duration of the test and for several weeks following the test. Phase 3: The third phase of hydrogeological characterization involved installation of two multi-level piezometers and a deep 6” diameter injection well completed to depths of 2,800 feet, followed by the performance of a nominal 30-day injection test (SRK, 2017). The piezometers were completed within the carbonatite at distances between 0.4 to 0.8 miles from the center of the injection well, which was located at the center of the orebody. The injection test was chosen as a test method over a standard pumping test due to the salinity of the groundwater and the expense of handling the discharge water. During the injection test, surface water from Todd Creek was injected at rates of between 350 to 480 gpm over a period of 33 days, including downtime. Response to the injection test was monitored over the duration of the test and for more than eight weeks following the test. Phase 4: The fourth phase of geohydrological characterization was conducted in 2025 during Phase 3 of the core drilling program, and involved the characterization of the hydraulics, porosity and groutability of the carbonatite (ABC, 2026). The program involved the detailed logging of water take and voids in the 15 coreholes drilled in 2025, detailed flow testing of three of the boreholes for permeability and hydraulic characterization of voids, and direct demonstration of groutability of the carbonatite in three boreholes using a variety of grout mixes. Groundwater hydrogeological characterization data collected in the four phases described above was completed by SRK, NioCorp, ABC, DGC, and the contract drilling companies present at the project site in 2014, 2015, and 2025. The data collection was conducted by Professional Hydrogeologists, Geologists, and Engineers in accordance with established procedures modified to be effective in the conditions presented at the Elk Creek mine site (ABC, 2026; SRK, 2017). 13.3.1 Conceptual Hydrogeology The Elk Creek Deposit is hosted in the Elk Creek Carbonatite, a volcanic carbonatite plug located in south-east Nebraska. The carbonatite plug is 3 to 4 miles in diameter and contains the orebody at its approximate center (Figure 13‐2). The carbonatite plug was vertically injected upward through and is surrounded by Precambrian age silicious rocks, which are of low permeability. This prevents significant lateral movement of water to or from the carbonatite, and together with the overlying marine sediments encloses the sodium
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 169 | Page chloride brine in the carbonatite. The brine appears to be a remnant of connate sea water captured in the carbonatite plug during the Late Cretaceous period 66 to 94 million years ago, when the site was covered by an inland sea (Naugle, 2018). The geology local to the orebody generally consists of a 50 to 100 ft thick layer of variable permeability Pleistocene-aged glacial till overlying 600-ft thick low-permeability Pennsylvanian-aged marine sediments, which rest on top of a moderate overall permeability Cambrian carbonatite volcanic plug extending to great depth (Figure 13‐3). Source: ABC 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 170 | Page Figure 13‐2:Regional Hydrogeology Source: ABC 2026 Figure 13‐3:Hydrogeology of the Elk Creek Mine – view looking northeast
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 171 | Page Glacial Till Pleistocene-aged glacial till covers the surface of the site, to a depth of between 40 to 100 feet. It is variably permeable, with lenticular glacial outwash features providing potable water to shallow wells that service local agriculture and homes. Water levels in these wells are typically within 30 ft of the ground surface. Pennsylvanian Sediments The Pennsylvanian sediments are made up of marine limestone, shale, and mudstone. The hydraulic conductivity of the Elk Creek Pennsylvanian Sediments has been evaluated by packer tests, active flowmeter tests, and laboratory tests on intact core. The results are compiled on Figure 13‐4 and the average is: Hydraulic conductivity of the Elk Creek Pennsylvanian Sediments = 0.002 ± 0.001 gpd/ft² (10-9 m/s) These marine sediments are functionally impermeable and will provide little groundwater inflow to the mine access drives and associated excavations The unit also functions as an aquiclude for vertical water movement, and effectively isolates the potable groundwater in the overlying glacial till from the brine in the carbonatite below. Water levels in wells completed in the Pennsylvanian marine sediments are typically 150 feet below ground surface, indicating a vertical downward head gradient from the glacial till above to the carbonatite below. However, due to the very low vertical permeability of the sediments, there is essentially no vertical downward groundwater flow through them, even over geological time scales. Cambrian Carbonatite The Cambrian age carbonatite unit is a volcanic plug made up of carbonatite (volcanic calcium-magnesium-iron carbonate) with siliceous lamprophyre rock masses interspersed throughout. The intact carbonatite and lamprophyre rocks are essentially impermeable, and the rock mass is generally lightly fractured, resulting in locally low hydraulic conductivity. However, the carbonatite is intersected by a small number of widely spaced, narrow, extensive and connected void zones. These are interpreted to be related to faulting and hydraulic fracturing that occurred during volcanic carbonatite emplacement and hydrothermal ore emplacement (ABC, 2026; SRK, 2017). These widely spaced void zones are the primary conduits for groundwater flow in the carbonatite and form a three-dimensional groundwater-flow network. Hydraulic Conductivity The hydraulic conductivity of the Elk Creek carbonatite has been evaluated by pump tests, injection tests, packer tests, active flowmeter tests, and laboratory tests on intact core. The results are compiled on Figure 13‐4 and the average is: Hydraulic conductivity of the Elk Creek Carbonatite = 3.3 ± 2.5 gpd/ft² (2×10-6 m/s) The results in Figure 13‐4 show four orders of magnitude range of permeability for a single geological rock type (carbonatite). This is unusual in geohydrology studies. The explanation is one of scale: the impact of the sparse high permeability void zones distributed through the otherwise functionally impermeable intact carbonatite. On the left of the figure there are four long packer tests which have hydraulic conductivity less than 0.001 gpd/ft² (5×10-9 m/s). This is approximately the permeability of intact carbonatite and lamprophyre (based on 28 laboratory permeability tests), indicating that
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 172 | Page the packer interval tested included no void zones, or any other significantly permeable features in the hundreds of feet of rockmass tested. To the right are the results of testing borehole intervals which are much more permeable; this permeability comes from one or more highly conductive void zones encountered in the test section. The hydraulic conductivity of a single void is proportional to the cube of the aperture, so variations in aperture creates large variations in permeability (Hoek & Bray, 1974). The observed large variation supports the conclusion that the permeability in each test is caused by a few narrow voids with varying aperture widths. Source: ABC 2026 Figure 13‐4:Hydraulic Conductivity of Geologic Materials at the Elk Creek Mine
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 173 | Page Porosity The void zones are also the main source of drainable porosity in the carbonatite. Drainable porosity is a key parameter for mine hydrology, as it controls the amount of water that will drain from the rock once the porewater pressure has been relieved. In addition – of importance to this project – at this site these voids have been shown to be large enough to be groutable, so it is also the groutable porosity: the volume of cured grout that would be required to seal a unit volume of carbonatite against flow. In Phase 4 of the Elk Creek hydrology investigation drainable porosity was evaluated by core analysis of vugs and voids, downhole geophysical surveys of voids, and flowmeter tests of circulation loss (ABC, 2026). The result is: Groutable porosity of the Elk Creek carbonatite = 0.09% ± 0.05% This is very low porosity for a carbonate or volcanic rockmass. The voids that make up the groutable porosity are relatively large – between 1 inch and 3 inches aperture. However, they are very sparse, with a spacing ranging from 100 to 500 feet of borehole. By contrast, the primary porosity of the intact carbonatite rocks is 1% or less, which is typical of an intact rock of almost any type. Permeability testing demonstrated that the porosity in the intact rock was effectively unconnected to the secondary porosity, due to the very low intact rock permeability (Figure 13‐4, shaded area). 13.3.2 Mine Inflow Control 13.3.2.1 Mine Inflow Inflow with no controls Based on the mine design in this report the mining will take place in a block of material within the carbonatite with the following approximate dimensions: Length (L) = 2,500 feet (NW-SE) Width (W) = 1,000 feet (NE-SW) Height (D) = 2,400 feet (600 feet to 3,000 feet below ground surface) The carbonatite block is submerged in brine with a current average piezometric surface 300 feet below ground surface. This brine exerts an average hydraulic head on the sides of the mined block as follows: Hydraulic head (H) = AVERAGE(600 ft, 3,000 ft) — 300 ft = 1,500 ft (650 psi) The average hydraulic conductivity of the carbonatite in the vicinity of the orebody was found by large-scale pumping tests to be in the order of 4 gpd/ft² (2x10-4 cm/s) (SRK, 2017). Using these data, the peak inflow to the mine during mining without any external inflow control is estimated by treating the mine as a large diameter well (Figure 16.3-4). Computations use the steady state radial flow equation (Theim, 1870): Q ≈ 2 π D K H / ln(R/r)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 174 | Page where: Q = mine inflow [gpm] D = height mine exposed to carbonatite [2,400 ft] K = hydraulic conductivity of carbonatite [4 gpd/ft² = 0.0028 gpm/ft²] H = average drawdown at the mine opening [1,500 ft] r = effective well radius of mine [≈ 1,000 ft] R = radius of influence of mine [radius of carbonatite ≈ 10,000 ft] Thus: Q ≈ 2π*(2,400 ft)*(0.0028 gpm/ft²)*(1,500 ft) / ln(10,000 ft/1,000 ft) ≈ 26,000 gpm This inflow is judged to be in excess of the inflow that could be safely allowed to flow into the mine or could be timely dewatered ahead of mining. Source: Adrian Brown Consultants 2026 Figure 13‐5:Mine inflow with no controls — Schematic Inflow with grouting control Accordingly, the decision was taken in the mine planning process to control the mine inflow and make the mine safe for operation by grouting the mining block. This would plug the karst voids with cement grout, which has a hydraulic conductivity of approximately 0.0004 gpd/ft² (2x10-8 cm/s) (Carmichael & Arulraj, 2017; Whiting, 1988). Intact carbonatite in the mining block has a hydraulic conductivity of approximately 0.002 gpd/ft² (7x10-10 m/s) (Figure 13‐4). Filling the karst voids within that material with cement grout would reduce the overall hydraulic conductivity of the grouted volume to that of the carbonatite intact rock. The grouting program is designed to limit the average mine inflow to 200 gpm, which is manageable from a dewatering and a water treatment perspective. To achieve this objective, it is necessary to grout the entire mining block to a minimum of 150 feet outside the proposed mined excavation, computed as follows.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 175 | Page As the mining progresses the grouted mining block will be "hollowed out", as the orebody is removed for processing, leaving a minimum 150-foot-wide grouted carbonatite flow barrier on all sides of the excavated mine. The mine will be at least partially backfilled with cemented fill after ore is extracted, but no credit is taken for the further resistance to inflow which this will create. Inflow to the interior of the mine through all sides of the grouted mine block at the end of mining is shown Figure 13‐6, and is computed using Darcy’s Law (Darcy, 1856): Q = K I A where: Q = inflow through all sides and the base of the orebody block [gpm] K = hydraulic conductivity of grouted carbonatite [0.002 gpd/ft²] H = average hydraulic head across flow barrier [1,500 ft] L = thickness of flow barrier [150 ft] I = hydraulic gradient = H / L' = (1,500 ft) / (150 ft) = 10 ft/ft A = area = 2*[(2,500 ft+1,000 ft)*(2,400 ft) + (2,500 ft*1,000 ft)] ≈ 22,000,000 ft² Thus, the peak steady brine inflow to the grouted Elk Creek mine at the end of excavation is approximately: Q ≈ (0.002 gpd/ft² / 1,440 min/day)*(10 ft/ft)*(22,000,000 ft²) ≈ 300 gpm Source: ABC 2026 Figure 13‐6:Mine inflow with grout control — Schematic 13.3.2.2 Groutability of the Elk Creek Orebody Groutability of fractured karst rock depends on the ability to deliver grout to the fractures and voids in the rock, and thereby to largely eliminate the ability of those conduits to convey groundwater to the mine workings. Cementitious grout is a mixture of portland cement, fly ash, blast furnace slag, bentonite, and fine-grained aggregate in water. After injection the grout cures to create a low permeability solid which seals the conduits. The Elk Creek carbonatite is an attractive candidate for grouting. It is a largely intact rockmass with a sparse network of voids. The voids can be intersected by grout injection boreholes and will readily
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 176 | Page accept grout (ABC, 2026). There are a number of lines of evidence from the investigations of the orebody that demonstrate the groutability of the Elk Creek Orebody: 1. Geology. The Elk Creek carbonatite is made up of essentially impermeable intact carbonatite, intersected with widely spaced narrow void zones ((SRK, 2017), App. 6K). These void zones are the only significant conduits for mine inflow and are also excellent high-transmissivity conduits for injection of grout to plug them. After the grout cures the resulting grouted rockmass has an overall permeability approximately equal to the intact rockmass permeability. 2. Drilling fluid take. During exploration diamond drilling approximately 10 gallons per minute of bentonite slurry is injected into the drill string to keep the drilling bit cool, lubricate the drill string to allow continued rotation, and transport the drill cuttings to the surface. Despite this, in all fifteen (15) drill holes in the 2025 drilling program in and around the orebody, circulation of this slurry carrying the drill cuttings was lost while drilling in the carbonatite. As a result, a measured total of 1,200,000 gallons of bentonite slurry and the drill cuttings it was carrying was inadvertently injected into the carbonatite. This demonstrates the ability of the carbonatite to accept large quantities of slurry and granular materials without plugging, which is an essential component of groutability. 3. Abandonment. After drilling, all boreholes in all of the Elk Creek drill programs were abandoned under supervision by the State of Nebraska. In general, this required filling the hole to refusal with low permeability material: high- viscosity bentonite slurry, topped off with neat cement grout. In all cases, this required the introduction of a volume of abandonment materials hundreds to thousands of gallons in excess of the volume needed to plug the borehole stem, indicating that even this high viscosity and rapidly-setting plugging material moved into the carbonatite formation readily through the voids. 4. Geohydrology. Three of the boreholes drilled in the 2025 Elk Creek program were tested for permeability by performing an active flowmeter test over their full length (ABC, 2026). This testing disclosed that essentially all of the flow injected during the tests (about 16 - 18 gpm) entered the formation in a few locations, each comprising less than a foot of the borehole length of 3,000 feet (Figure 13‐4). This confirms that the permeability of the Elk Creek orebody occurs in a small percentage of its length, and that those permeable sections must be of very high permeability, typical of voids, and easily groutable. 5. Direct demonstration. At the conclusion of the 2025 Elk Creek Mine drilling program a total of three groutability tests were performed (ABC, 2026). In these tests grout was injected by hand in batches to the full depth of the borehole until refusal. A variety of grout mixes were tested, including neat portland cement, neat ultrafine cement, and cement-bentonite, with and without retarding plasticizer to reduce the slurry viscosity and increase the time that the grout remained fluid. The results are that it was possible to inject as much as 12,000 gallons of cement grout into the formation through a single hole. This injection had the ability to plug the karst sheets encountered in the borehole to a computed distance of approximately 30 feet radially from the hole before the grout cured in about two days. This result was the same for grout using portland cement and ultrafine cement, both of which required the addition of a retardant to increase the setting time to be equal to or greater than the total time required for injection.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 177 | Page Source: ABC 2026 Figure 13‐7:Geophysical tests showing widely spaced high permeability flow zones (left panel) and corresponding widely-spaced large aperture voids (right panel)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 178 | Page 13.3.2.3 Grouting Design Grout quantity The void volume required to be sealed in the entire mined volume is approximately 0.09% of the mine orebody volume: Vvoids ≈ 0.0009*(2,500 ft)*(1,000 ft)*(2,400 ft)*(7.48 gal/ft³) ≈ 40 million gallons Thus, grouting of the entire mining block will require approximately 40 million gallons of cured grout. Grout mix The grout mix demonstrated to be effective for injection at Elk Creek to produce 1,000 gallons of cured grout in the carbonatite is as follows: Portland cement: 5,000 lb Water: 1,000 gallons Plasticizer/retarder: 30 lb Accordingly, the total material usage for the project grouting is: Portland cement: 100,000 tons Water: 40,000,000 gallons Plasticizer/retarder: 600 tons Cured grout volume: 40,000,000 gallons Grouting method Grouting of the orebody and the immediately surrounding carbonatite will be conducted in two phases: Phase 1: Primary grouting from surface. Grouting from surface under gravity with 68 holes in a grid with an average spacing between holes of 300 feet, and a length averaging 2,500 feet. Surface grout holes: 68 holes @ 2,500 ft ≈ 170,000 feet Phase 2: Dental grouting from underground. Horizontal grout holes drilled through a blowout preventer in advance of each development and stope, oriented NW-SE, spaced 150 feet apart horizontally and vertically, grouted under high pressure to refusal where continuous inflow of water is encountered. Underground grout holes: 5 holes/level x 24 levels x 2,500 ft ≈ 300,000 ft Surface Grout Hole Design The surface grouting will be conducted through a total of 68 deep grout holes, installed as shown in Figure 13‐8, Figure 13‐9, and Figure 13‐10. Grouting Concept The grouting concept is as follows: 1. Grouted carbonatite flow control wall. An outer grout wall will be constructed, with injection wells spaced at 150 feet around the ends of the planned ore stopes. Grout will be
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 179 | Page injected to refusal, with injected grout spreading out to a minimum of 150 feet beyond the planned location of the outermost stope headwall. This grouted “shell” provides flow control to 300 gpm throughout the mine life and also provides a stable outer wall to resist the water forces created by the high-pressure brine in the adjacent brine aquifer. 2. Stoping area grouting. The stoping area inside the flow control wall will be grouted at 300 feet spacing inside the stoping area. This is designed to block any karst conduits within the stoping area, so as to minimize inrushes through conduits that have not been sealed by the flow control wall, and to minimize the underground dental grouting that would be required to seal them. 3. Access drive area grouting. Inflow to the access drives located to the southwest of the stope area will be achieved by targeted grouting at approximately 300 feet spacing. It is expected that this surface grouting will limit inflow to the drives, with any remaining inflow being sealed off with underground grout holes drilled in advance of the development drifting. For project access timing purposes, the access drive area grouting will be conducted from southeast to northwest first, followed by the installation of the flow-control wall and stope-area grouting from southwest to northeast. Source: ABC 2026 Figure 13‐8:Grout hole location plan, showing grouting boreholes, development drifts, mining stopes and sections.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 180 | Page ‘ img170397038_94.gif Source: Adrian Brown Consultants, 2026 Figure 13‐9:Section A-A' looking northeast, showing geology, grouting boreholes, development drifts, and mining stopes
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 181 | Page img170397038_95.jpg Source: ABC 2026 Figure 13‐10: Section B-B looking northwest, showing geology, grouting boreholes, development drifts, and mining stopes
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 182 | Page 13.3.2.4 Grout hole drilling The surface grout holes will be drilled as follows: 1. Vertical holes. All grout holes will be drilled vertically to the total depth of the mine in the hole location. Vertical holes are the easiest and quickest to drill, and result in the minimum length of drilling for the project. Grouting effectiveness will be monitored during the project, and in the event that significant vertical karst features are present and are not grouted, the inclination of the grout holes will be adjusted. 2. Full depth grout holes. All grout holes will be drilled to lowest level of mining at the hole location prior to any underground activity in or near that location. This will free the underground works areas for safe operation with respect to drilling impact, inrush impact, and stope wall blowout. Grouting of the carbonatite rockmass to full depth is expected to seal off upflow through the base of the mine at all levels prior to any mining. Drilling technology Grout holes must be drilled to avoid plugging of the formation during drilling, and to create a borehole with sufficient capacity to allow injection of as much as 500,000 gallons of low-viscosity grout in each hole within 48 hours. The drilling specification to achieve this performance is as follows: 1. Reverse air dual-string rotary drilling. This drilling technique involves injection of compressed air into the drill string to air lift drill fluid and cuttings to the surface inside the drill string. The drill fluid return is screened to remove cuttings, and the resulting cuttings-free return is conducted down the drilling annulus. This prevents injection of the coarse rotary cuttings into the karst formations intersected by the drilling, leaving the voids open to accept grout at the completion of drilling. 2. Six-inch drilling. In order for the borehole to be able to conduct the required grout injection flow (500,000 gallons in 48 hours), it must be capable of passing a minimum of 200 gpm of low viscosity slurry down as much as 3,000 feet of well under gravity (which creates an available injection head loss of approximately 400 feet of water). This requires a 6-inch internal diameter well, which is readily advanced by rotary drilling. Grouting technology The grouting technology required to support the Elk Creek Mine water control project is as follows: 1. Batch Plant: A centrally located batch plant capable of continuous operation for 48 hours with a production of 500,000 gallons of grout slurry at a minimum rate of 200 gpm (Figure 13‐11). 2. Delivery: Pipe or ready-mix trucks operating 24 hours a day during grout injection. 3. Injection: Grout will be piped or poured into the well under gravity. 4. Completion: Injection will continue until refusal at each well, to ensure sealing of the void conduits.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 183 | Page Figure 13‐11: Example of a mobile concrete batch plant (Photo courtesy of Techwill Inc.) 13.3.2.5 Inrush Safety Mining of the Elk Creek orebody will result in the removal of ore from stopes that extend out to within 150 feet of the edge of the grouted carbonatite mine block. Outside of that grouted block there will be up to 2,700 feet of brine with a head pressure up to 1,400 psi. The mine pillars will be unsupported at various times during mining and will have to safely withstand the full applied lateral brine pressure. Safety against blowout The grouted wall at the end of the outermost stope in each level constitutes a 130 foot by 50-foot plug, which has to resist the applied force of the brine (Fw) (Figure 13‐12). This force is substantial: at full depth of the mine it is approximately 500,000 tons. It is resisted by friction on any fractures that are at the periphery of the plug (Fs). If the water force exceeds the resisting frictional force, the stope wall blows in to the stope, connecting any high-capacity karst water conduit outside the grouted envelope to the mine. The inrush flow would be sudden and large: up to 2,000 gpm. Blowouts of this size are hazardous to mining personnel, impact mine production, and are difficult and expensive to repair. To ensure mine safety against blowout, the stability of the terminal stope wall plug has been evaluated (ABC 2026). To create a 99% confidence that the stope wall will be safe against blowout over the entire mine depth requires the grouted wall to be no less than 80 feet thick. This is achieved
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 184 | Page in the design by surrounding the entire stopped volume of the mine with a line of full-depth grout holes spaced 160 feet apart and located outboard of the terminal wall of each line of stopes on each level, and grouting them to provide the 150-foot-thick flow control barrier. Figure 13‐12: Stability of grouted stope outer pillar against water drive — Force diagram Safety against pillar collapse The terminal stopes in the mine are supported by pillars extending out into the un-mined carbonatite. These pillars are grouted and are subject to the lateral force exerted by the unrelieved brine pressure on their outer surface (at the limit of the grouting). Accordingly, they are laterally loaded columns, and they have to be thick enough to safely carry the load of the overlying rock while resisting the lateral brine load. If they are too thin, they will bend and fail progressively in compression on the stope face, resulting in inrush. This safety of the terminal stope pillars against collapse has been evaluated using 3-dimensional numerical modeling (A2GC, 2026b). A typical cross-section of the analyses is presented in Figure 13‐13. Based on that analysis, the 150-foot-thick grouted terminal stope pillar will be stable with respect to stope pillar collapse. This is achieved in the design for inflow limitation and blowout mitigation.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 185 | Page Source: A2GC, 2026 Figure 13‐13: Vertical stress in 65.6 foot- (20 meter) thick and 131.2 foot- (40 meter) high grouted stope outer pillar located 3,280 feet (1,000 meters) below ground surface with 10 MPa (1,450 psi) water drive applied to outer edge of terminal pillar (blue arrows). All stresses reported in MPa, mesh blocks are 3.28-foot (1-meter) cubes. Environmental Protection The Elk Creek mine grouting program drills 68 deep injection boreholes and emplaces fifty million gallons of liquid grout containing cement, water, and plasticizer through them into the Elk Creek Carbonatite. The impacts to the environment are evaluated and where necessary mitigated as described below. Drilling impacts Drilling will be accomplished by reverse-air rotary technology, in which compressed air is injected into the drill string and drill water and drill cuttings are air-lifted through an inner drill pipe to the surface. All brine that is raised to the surface in this process will be re-injected down the drill hole annulus after removal of cuttings. All boreholes will have a steel casing through the surficial till materials, to protect the fresh water in them from impact. Drilling will be conducted under standard environmental protection requirements, which contain all drilling fluids and other materials to the
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 186 | Page drill site. Following drilling, all boreholes will be abandoned by grouting to refusal. No significant impacts are expected to the carbonatite brine aquifer. Grout impacts The grout to be used in the Elk Creek project is a chemical mixture of non-hazardous constituents, which cures when injected and forms an effectively impermeable mass. In doing so, it immobilizes any chemical constituents in it, rendering them incapable of impacting the environment. The impact to the environment of the grout will be insignificant, the same as the impact to the environment of cured concrete in any other setting. The grout is being introduced into an isolated brine aquifer, in which the natural salinity is in the order of 18,000 mg/L TDS (mainly NaCl). Accordingly, the grout program will not change the use category of the water in the aquifer, which is non- potable. Brine displacement impacts The grouting will inject 50 million gallons of grout into the carbonatite brine aquifer. This will displace a like volume of brine away from the mine block. It is important that the displaced brine does not emerge at the surface or in the shallow drinking water aquifer in the surficial glacial till. It will not, for the following reason. The current brine piezometric level is approximately 300 feet below ground surface. Thus any displaced brine would need to raise the water table in the carbonatite at least this amount before brine could appear on the surface. An injection test was conducted in the carbonatite in 2017 (SRK 2017). In the test fresh water was injected at a rate of 350 to 480 gpm over a period of 33 days. This caused a maximum stabilized increase in the brine level in the carbonatite close to the injection well of approximately 30 feet. This is approximately the same maximum injection rate that is anticipated for the grouting, so the head build-up should be no greater than in the test. If so, the brine level in the aquifer is expected to rise to no higher than about 270 feet below ground surface, far lower than would allow discharge of brine to the surface or the surficial glacials from this cause. 13.4 M INE D ESIGN 13.4.1 Selection of Mining Method The mining method selected for this ore body was based on modifying factors such as economic parameters and geotechnical information, ensuring it was suitable for the mineralized geometry. A number of studies from the recent past have evaluated different mining methods for this deposit, such as caving, open or sublevel stoping, or room and pillar methods. Due to its depth and the requirement to have selectivity in mill feed grades, the underground longhole stoping method (LHS) was determined as a suitable mining method. Given the bulky geometry of the deposit, a block caving or sub-level caving method also could have been considered economically viable. However, the limited selectivity of such methods would not allow for optimizing the higher value of this deposit given the mill production constraints. To maximize the recovery of the high-grade zones, the longhole stoping method utilizing cemented paste backfill was chosen. Figure 13‐14 below shows a cross-sectional view of the current mine design. Three large blocks of resources are defined by the mine plan and will generally be mined together in a declining FeNb grade strategy.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 187 | Page Source: Amplify Mine Planning, 2026 Figure 13‐14: 2026 Current Design The stope dimensions are planned to be 49 ft wide, with stope lengths varying based on Nb2O5 mineralization grade from 33 ft to a maximum of 49 ft per panel, and a maximum level spacing height of 131 ft. The varying stope length allows for optimizing the Nb2O5 grade with a minimal increase in operating costs. The level spacing of 131 ft was designed because of its beneficial operating and sustaining capital costs. Each block is mined with a bottom-up sequence. A sill pillar level is designed to be left between each of the three mining blocks until that sill level is scheduled to be partially mined. The extraction of ore from the sill pillar level is expected to be 62.5% by volume using production upholes drilled through the first 82 ft of the bottom of the 131 ft thick sill pillar. The mining of the sill pillar is scheduled only after the upper block immediately above is mined out and is accounted for within the reserves. This methodology will allow partial mining of ore on the sill pillar level, while at the same time allowing the development of the lower mining blocks as well as establishing an earlier start to the mining of the upper mining block. Using this approach minimizes the impact on initial capital investment. The backfill was designed to have adequate strength after curing to allow for mining adjacent to filled stopes, thus eliminating the need for rib pillars. The mine design process centered on using four Deswik© modules – Mine Design, Stope Optimizer, Sequencing, and Scheduling software to determine potentially mineable areas based on 4 main parameters: • Estimated minimum cut-off net smelter return (CoNSR) value • Nb2O5 grades • Mining dimensions parameters • Geotechnical design and sequencing constraints The reader should note that since the stope cut-off grade value based on overall mining costs (CoG) of $218/ton is much lower than the resulting average stope CoNSR value of roughly $591/ton, the CoNSR was not the only decisive factor in the stope optimization process. Mining dilution of
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 188 | Page approximately 6% was applied to all stopes and development, based on 3% for the primary stopes, 9% for the secondary stopes, and 5% for ore development. The mining dilution was added to the designed tonnage to account for unplanned sources of dilution such as backfill and host rock around the periphery of the ore mass. An ore recovery factor of 95% was applied to account for unrecoverable ore left within the stopes. The mine design and schedule were based on recognizing a milling design constraint of 3,047 tpd as defined by NioCorp’s design process. At this rate, the mill is expected to produce approximately 8,282 t/y of ferroniobium during the years of full production. Planned mine life of mine of about 43 years with 40 years at full production. Optimization work indicated that the grade of Nb2O5, (0.803%) at a unit NSR of US$ 591/ton could sustain and produce a consistent ferroniobium production over the LOM. Scandium trioxide and titanium tetrachloride as well as six rare earth metals (Dy2O3, Nd2O3, Pr2O3, and Tb2O3, Sm-Eu-Gd carbonate, Ho-Er-Tm-Yb-Lu-Y carbonate) that accompany the ferroniobium production in the mine plan. NioCorp favored a higher Nb2O5 COG approach to maximize the LOM NPV for production scheduling while at the same time maintaining the annual ferroniobium target. 13.4.2 Stope Optimization As mentioned in Section 13.4.1 the minable shape optimization software module provided by Deswik© was used to determine potentially mineable areas based on 1) cut-off net smelter return (CoNSR) calculation provided by NioCorp, 2) Nb2O5 grades provided by DGC, and 3) mining dimension parameters designed by Amplify Mine Planning and Dumas. The estimated cut- off NSR value (CoNSR) of US$ 218/t provided by NioCorp was used as a starting point for the analysis. As the CoNSR value is much lower than the resulting average stope NSR revenue value, the CoNSR was not the decisive factor in the stope optimization process. Rather than using just a minimum CoNSR, the mine design also targeted an average cut-off Nb2O5 grade of 0.65% and a milling constraint of 3,047 tpd which resulted in a steady-state average annual ferroniobium production of 8,282 tons during the years of full production. This strategy results in a LOM NSR average value of US$590.84/ton. Figure 13‐15 and Table 13‐7 below show the mineable stopes optimized for varying CoNSR scenarios. An average dilution of approximately 6% was added to the designed tonnage which accounts for unplanned sources of dilution such as backfill and the host rock around the periphery of the ore mass while a recovery factor was applied to account for unrecoverable material which will be left within the stopes. The average dilution was derived from applying 3% dilution by volume to primary stopes, 9% dilution by volume to secondary stopes, and 5% dilution by volume for development drifts. As discussed in Section 12, the dilution is a natural consequence of the mining process and the defined amounts of dilution by mining type reflects Amplify Mine Planning’s understanding of the unique facts and data of the deposit and used in the mine planning process and acknowledges the relevant accuracy of those facts and data applied during the planning process to create a successful mining plan.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 189 | Page Source: Amplify Mine Planning, 2026 Figure 13‐15: Undiluted Stope Optimization Results for Varying NSR Cut-Offs Table 13‐7: Undiluted Stope Optimization Results for Varying NSR Cut-offs Source: Amplify Mine Planning, 2026 13.4.3 Stope Design Figure 13‐16 shows a cross-sectional sketch of a typical 2-level and primary/secondary stope extraction design. The stope width is a constant 49 ft with a vertical height of 131 ft from sill to sill. The length (depth) of the stopes is designed to a maximum panel length of 49 ft and a minimum panel length of 33 ft. Figure 13‐17 shows a typical level arrangement of the stopes, cross- cuts, footwall
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 190 | Page drive, ramp and other infrastructures servicing a single level. The mine plan stope orientation is perpendicular to the general strike of the deposit, which is 20° off the measured principal stress. This offset will not have a significant impact on stope stability. The actual planned stope lengths currently have a maximum length of 49 ft in both fresh and moderately weathered rock, which is a conservative design in relation to the stability assessment described in Section 13.2.2. Source: Amplify Mine Planning, 2026 Figure 13‐16: Stopes and Crosscut Accesses (Cross Section View)
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 191 | Page img170397038_103.jpg Source: Amplify Mine Planning, 2026 Figure 13‐17: Level Layout with Stopes and Footwall Accesses (Rotated View Looking North) 13.4.4 Development Design The production stopes are accessed through a footwall drive drift that is offset approximately 82ft from the nearest edge of a stope. The crosscuts (x-cuts) are driven into the center of each target primary or secondary stope from the footwall drive, as shown in Figure 13‐18. This figure provides a plan view showing the distinct offset difference between the mine access/infrastructure locations which are offset to the production stopes located in the deposit. Source: Amplify Mine Planning, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 192 | Page Figure 13‐18: Completed Mine Design (Plan View) These footwall access drifts are connected by the ramp system and further connect to ventilation raises, and on some levels, they are connected to the secondary haulage ramp which contains the Railveyor© train. Much of the mine infrastructure is located in waste rock, but some infrastructure areas can be found in lower grade material as it gets closer to the ore body. The designed vertical extent of the mine production area is approximately 2,380 ft, with a bottom elevation of roughly 3,050 ft below the surface elevation. Figure 13‐19 shows the completed mine design highlighting several main infrastructure areas and the vertical extent of the current mine plan. The ramps, internal slot or drop raises, and underground infrastructure included in the design are discussed in other subsections. The three mining blocks are generally mined simultaneously, based on declining grade strategy using a primary/secondary stoping sequence that will utilize cemented paste backfill to support the mined-out stopes once the backfill is cured. Altogether, they provide an estimated life-of-mine (LOM) of 43 years. The primary access ramp and secondary haulage ramp are designed to reach a depth of roughly 3,050 ft below the surface. Source: Amplify Mine Planning, 2026 Figure 13‐19: Completed Mine Design (Cross Sectional View) Figure 13‐20 is a closer view of the mine in profile view looking south showing main infrastructure locations and their connection to the main producing stopes.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 193 | Page Source: Amplify Mine Planning, 2026 Figure 13‐20: Completed Mine Design - Main Infrastructure (Looking South) Figure 13‐21 and Figure 13‐22 show the mine design colored by Nb2O5 grade and NSR, respectively. img170397038_107.jpg Source: Amplify Mine Planning, 2026 Figure 13‐21: Mine Design Coloured by Nb2O5 Grade.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 194 | Page img170397038_108.jpg Source: Amplify Mine Planning, 2026 Figure 13‐22: Mine Design Coloured by NSR ($/t) Table 13‐8 Summarizes the mine design by activity type. Table 13‐8: Mine Design Summary - by Activity Type General Summary Units LOM Statistics Ore Tons (T) 45,929,463 FeNb Tons (T) 316,099 Nb2O5 Grade - Mined (%) 0.759 Sc Grade - Mined (ppm) 69.3 TiO Grade - Mined (%) 2.68 TREO Grade - Mined (ppm) 3,447 Development Ore Tons (T) 1,135,621 Stope Production Tons (T) 44,793,842 Total Waste Tons (T) 6,482,430 Total Tons Moved (T) 52,436,964 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 195 | Page General Summary Units LOM Statistics Lateral Development: RAMP DEVELOPMENT (ft) 38,711 LEVEL ACCESSES (ft) 13,040 PRODUCTION LEVELS (ft) 33,872 STOPE DEVELOPMENT (ft) 184,184 LOADOUTS (ft) 5,219 AUXILIARY LATERAL DEVELOPMENT (ft) 23,035 TOTAL LATERAL DEVELOPMENT (ft) 298,061 Vertical Development: RETURN AIR RAISE (ft) 130 ORE BIN (ft) 394 ORE PASS (ft) 1,837 ORE PASS FINGER (ft) 940 WASTE BIN (ft) 394 WASTE PASS (ft) 1,838 WASTE PASS FINGER (ft) 887 TOTAL VERTICAL DEVELOPMENT (ft) 6,420 Source: Amplify Mine Planning, 2026 13.4.5 Mine Access 13.4.5.1 Dual Portal Box Cut The underground mine will be accessed via a purpose-designed box cut excavation incorporating two portals, designated as the Service Portal (also referred to as the North Portal) and the Production Portal (also referred to as the South Portal). These portals terminate at the closest finished face of competent bedrock beneath the overburden, thereby establishing stable entry points into the underground workings in accordance with standard industry practices for portal location and development. At the rock interface, the two underground decline ramps—the North Service Ramp and the South Production Ramp— commence, providing controlled access to the various production levels of the mine. At the time of this report, construction of the mine portal box cut has commenced on site. For the purposes of the economic analysis and establishment of capital costs in this Technical Report Summary, the portal box cut, associated sockets, and fresh air raise are assumed to be fully completed and available for operations. Actual capital expenditures incurred to date for portal construction will be tracked separately and reconciled against the study estimates as detailed engineering and construction progress. The mine access box cut area will remain excavated and will not be backfilled, ensuring permanent, open access for ongoing operations, maintenance, and emergency response. Highwalls of the box cut will be stabilized in full compliance with site- specific geotechnical recommendations and established best-practice guidelines for slope and bench stability. Stabilization measures will incorporate
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 196 | Page appropriate batter angles, benching where required, and systematic ground support systems (such as fibre-reinforced shotcrete, welded mesh, rock bolts, and cable bolts) to mitigate rockfall hazards, erosion, and potential instabilities in the near-surface weathered zone. These designs are derived from detailed geotechnical investigations, kinematic and numerical stability analyses, and engineering best practices, ensuring long-term reliability of the access infrastructure. The box cut floor will descend from the original surface start point at a gradient of 15%. From the portal rock interface, the North Service Ramp will decline to the mine bottom at a gradient of 15%, while the South Production Ramp will continue at an 18% gradient. This dual-ramp configuration within a single box cut excavation follows proven technical approaches for similar underground operations, where twin declines enable functional separation of traffic while maintaining a compact surface footprint and optimized geotechnical conditions at depth. The North Service Ramp will serve as the primary means of egress to the underground mine for personnel and vehicular traffic, supporting safe, efficient movement of workers, equipment, and materials under normal operating conditions. The South Production Ramp will be dedicated to production activities utilizing a Railveyor conveyance system for the continuous transport of ore and waste materials from underground to the designated surface dumps. In addition, the South Production Ramp will function as an alternate means of egress during emergencies, providing essential redundancy and thereby reducing the overall risk profile associated with single-access scenarios in accordance with contemporary mine portal design principles. Both the North and South Portal Ramps will incorporate a short enclosure extending from the rock interface, sufficient to provide localized weather protection and structural transition at the portal face while aligning with the service-oriented functions. Surface runoff entering the box cut excavated area will be collected and pumped to the site’s stormwater pond independent of the mine dewatering system. This arrangement incorporates dedicated sumps and pumping capacity as part of comprehensive surface water management, preventing inundation, erosion, or uncontrolled water ingress into the mine and ensuring compliance with environmental and operational safety requirements. 13.4.5.2 Fresh Air Raise The underground mine incorporates a purpose-developed fresh air raise as a third independent mine access opening, providing vertical ingress and egress to the underground workings as a redundant pathway in addition to the primary dual-portal box cut excavation (North Service Portal and South Production Portal). This raise is established as a vertical shaft commencing at a stabilized surface collar and extending through overburden and competent bedrock to connect underground via a horizontal drift, thereby ensuring multiple means of access and egress in compliance with regulatory requirements and contemporary mine design standards for operational safety and emergency preparedness. Raise collar construction establishes a secure foundation through installation of secant piles within the glacial till overburden, followed by a steel-reinforced concrete collar pad. The upper coping section of the raise is excavated mechanically through stiff to very stiff lean-to-fat clay glacial till, with a steel-reinforced, cast-in-place concrete liner installed in staged lifts to maintain ground control, dimensional accuracy, and groundwater isolation. The intermediate section transitions into un- weathered to slightly weathered shale and moderately hard limestone, where excavation shifts to controlled drill-and-blast methods. A concrete liner is placed in coordination with sinking advances
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 197 | Page to ensure structural continuity and long-term stability. Upon completion of the vertical raise, an access drift is developed to establish the underground connection, with ground support comprised of rock bolts, wire mesh, and shotcrete. This raise-and- drift development provides a stable, permanent access opening sized and supported in accordance with the variable ground conditions encountered. To enable safe personnel movement within the fresh air raise and to provide a dedicated third means of access and egress should the primary portal entrances become compromised, a suitable man-way ladder system is incorporated throughout the vertical raise. The ladderway is designed in accordance with MSHA standards (30 CFR § 57.11036–57.11041) and industry best practices for shaft escapeways. It features fixed ladders with a minimum unobstructed cross-sectional opening of 24 in × 24 in measured from the ladder face, substantial landings or offset ladder sections with gates at intervals not exceeding 30 ft for ladders steeper than 70° from horizontal, and protective cages or equivalent fall-arrest systems where required. The manway provides direct vertical access from surface to the underground drift connection, ensuring rapid self-escape or rescue team intervention independent of the ramp portals. Collectively, the dual-portal box cut and the fresh air raise establish a robust, multi-redundant mine access framework. This configuration enhances personnel safety and operational resilience while meeting geotechnical, regulatory, and infrastructure requirements for permanent underground access. All elements are engineered for long-term structural integrity, groundwater control, and seamless integration with the overall mine development. 13.5 P RODUCTION S CHEDULE The production schedule is based on the mine design and access to defined reserves as discussed in previous sections. In general, a strategy of prioritizing grade for Nb2O5, while following a bottom-up pyramidal stoping sequence via scheduled, available development access drifts provides the basis for the production schedule. 13.5.1 Productivity Productivities for mine development and production were derived from first principal calculations by Dumas. Additional input from supporting mining contractors, blasting suppliers, and other equipment vendors were used by Dumas to assist with estimating the key parameters. The rates developed from first principles were also subject to potential adjustments based on relevant benchmarking and the experience and judgment of the mine design team. The productivity rates used for mine scheduling are shown in Table 13‐9, followed by a description of the general and activity-specific parameters upon which the productivity rates are based. Typical dimensions by heading types are presented in Table 13‐10. These will all be developed by contractors in accordance with the productivity rates and levelled in the schedule by crew assignments. Table 13‐9: Productivity Rates Activity Type Dimensions Rate Lateral Development Priority Face See Table 16-10 16.4 ft/d Non-Priority Face 9.8 ft/d
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 198 | Page Activity Type Dimensions Rate Vertical Development Fresh Air Raise 13 ft diameter 9.8 ft/d Return Air Raise 13 ft diameter 9.8 ft/d Ore Bin 20 ft diameter 3.3 ft/d Waste Bin 20 ft diameter 3.3 ft/d Conical Sump 16 ft diameter 3.3 ft/d Ore Pass Finger 6.5 ft x 6.5 ft 9.8 ft/d Waste Pass Finger 6.5 ft x 6.5 ft 9.8 ft/d Ore Pass 9.8 ft x 9.8 ft 9.8 ft/d Waste Pass 9.8 ft x 9.8 ft 9.8 ft/d Stoping Slot Development - 10.5 d Drilling - 656 ft/d Stope Production - 1020 t/d Backfill Preparation - 10.0 d Backfilling - 42,378 ft³/d Backfill Curing - 28.0 d Source: Amplify Mine Planning, 2026 Table 13‐10: Dimensions by Heading Types Heading Types Width (ft) Height (ft) Area (ft) Rate RAILVEYOR BYPASS 26.2 19.0 499 16 ft/d LEVEL AXS 18.0 19.0 343 16 ft/d LOADOUT 18.0 19.0 343 16 ft/d MUCKBAY 18.0 19.0 343 10 ft/d PASSING BAY 18.0 19.0 343 16 ft/d RAMP 18.0 19.0 343 16 ft/d RAMP ACCESS 18.0 19.0 343 10 ft/d FRESH AIR ACCESS 14.8 14.8 218 10 ft/d LATRINE 14.8 14.8 218 10 ft/d PRODUCTION LEVEL 14.8 14.8 218 16 ft/d ELECTRICAL LOAD CENTER 14.8 14.8 218 10 ft/d ORE PASS ACCESS 14.8 14.8 218 16 ft/d PARKING BAY 14.8 14.8 218 10 ft/d PRIMER MAGAZINE 14.8 14.8 218 10 ft/d RETURN AIR ACCESS 14.8 14.8 218 10 ft/d SUMP 14.8 14.8 218 10 ft/d WASTE PASS ACCESS 14.8 14.8 218 16 ft/d MAIN SUMP 14.8 17.1 252 10 ft/d POWDER MAGAZINE 14.8 17.1 252 10 ft/d 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 199 | Page Heading Types Width (ft) Height (ft) Area (ft) Rate REFUGE BAY 14.8 17.1 252 10 ft/d STOPE DRIFT 14.8 17.1 252 10 ft/d STOPE CROSSCUT 14.8 17.1 252 10 ft/d DRILL BAY 14.8 17.1 252 10 ft/d SHOP 23.0 23.0 527 10 ft/d CHARGING STATION 29.5 19.0 562 10 ft/d WAREHOUSE 29.5 19.0 562 16 ft/d Source: Amplify Mine Planning, 2026 General Parameters Table 13‐11 provides the general schedule parameters applicable to all underground mining activities for the ramp-up period and life of mine production. Table 13‐11: Workforce Schedule Parameters for Underground Schedule Parameters Value Units Annual Mining Days 365 days/yr Mining Days per Week 7 days/wk Shifts per Day 2 shifts/day Scheduled Shift Length 12 hrs/shift Pre-shift meeting 15 min Travel to work area via ramp or cage 15 min Inspection pre-start 10 min Lunch 30 min Cleanup and setup for cross shift 10 min Travel to surface 10 min Handover meeting 10 min Non-productive time 100 min Work Time 620 min Total Work Time Per Shift 10.33 hr/shift Total Work Time per Day 20.66 hr/day Efficiency 86.10% Source: Dumas 2026 Refer to Section 13.2.2.6 for detailed ground support requirements. The mine plan has conservatively designed a plan using grouted rebar in the back (roof) of all excavations. Split sets are designed for walls of all excavations, but not in the roof (back). 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 200 | Page 13.5.2 Box Cut, Portal and Ramp Development The proposed box cut design dimensions are shown in Table 13‐12 and Figure 13‐23. Construction of the box cut commenced in February 2026 and is fully funded. The descriptions herein are provided for completeness, but costs are not included in the economic model associated with this technical report, as the box cut will be complete before the balance of project execution is undertaken. The portion of the box cut that lies within the bedrock has a high wall at a 75° angle. The portion of the box cut that lies within the overburden and shale will have 1:1 sloped wall with benches at 41’ heights. Table 13‐12: Cut Design Dimensions Box Cut Dimension Unit Value Length ft 1,228 Width ft 320 Maximum Depth ft 132 Excavation Volume Yd³ 628,423 Source: Dumas, 2026 img170397038_109.jpg Source: Dumas, 2026 Figure 13‐23: Box Cut Design Dimensions – Plan View Looking Northeast The box cut slopes in the overburden will be soil nailed to preserve the 1:1 slope per the GSI proposal #168695633 (Figure 13‐24).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 201 | Page Figure 13‐24: GSI Proposal for Slope Stability The initial ramps are both going to be driven at the same time (18 ft wide x 19 ft high) from the box cut and proceed down to 210L, shown in Figure 13‐25. Ventilation loops will be established as the ramps are driven by breaking through from one ramp to the other. The South Ramp will be used for the Railveyor and driven at 18% maximum grade and will facilitate the movement of both ore and waste as well as being the main ventilation path for the return air. The North Ramp will facilitate the movement of larger mining equipment, services and the workforce to and from the mine and will be driven at 15% maximum grade. It will also act as the fresh air path for the mine ventilation system. Source: Dumas, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 202 | Page Figure 13‐25: Initial Ramp Development – Isometric View Looking North 13.5.3 Primary Haulage Ramp & Secondary Access Ramp The ore body will be accessed by two spiral access ramps at decline angles of 15 and 18 degrees from the face of a box cut ramp and spaced a minimum of 16.4ft between the ramp openings. Excavating both spiral primary haulage and secondary access ramps will be carried out simultaneously. In addition, a short vertical shaft will be excavated in the development timeline connecting the surface to the primary access ramp to provide a route for air ventilation supply purposes. The main mine fan will be constructed at the surface of this shaft to provide ventilation to the mine as well as cooling and heating depending on the time of year. Driving both ramps simultaneously allows the initial lateral development entries to begin from the first sill level location of the primary haulage ramp while the primary haulage and secondary access ramps continue to be excavated to lower elevations to facilitate extraction of higher niobium grade stopes located at the lower levels. The primary haulage ramp will be excavated to a total depth of 3,050 ft and is estimated to be a total 18,240 ft in length. The secondary access ramp will also be excavated to the depth of 3,050 ft given an estimated total length of 20,360 ft. The primary haulage and secondary access ramps will be excavated simultaneously using conventional mine drilling and blasting methods in conjunction with probe drilling and grouting as needed ensure ground water in-flow control. The planned rate of excavation averages 16.3 ft/d; this rate was developed in collaboration with mine contractors given the strata material expected to be encountered. The average rate captures the activities of drilling, blasting, mucking, and bolting, with experiential rate adjustments due to rock types and shaft depth. The ore or waste material will be removed by an LHD which loads into a mine truck and hauls the waste and ore to the surface until such time as the vertical muck raises are excavated and the Railveyor is installed and operational. Both ramps are developed to finished dimensions of 18 ft wide by 19 ft high which excludes the required cement lining thickness required for the ground support program, discussed earlier. These ramps have been sized to allow the safe passage of required production equipment, personnel, mining parts and supplies, service lines, and most importantly, the ventilating air required to dilute, render harmless, and carry away all noxious gases and dusts from mining operations. The secondary access ramp will be excavated with the same dimensions and method as the primary haulage ramp also to a depth of 3,050 ft. Conventional drifting coupled with a probe drilling and grouting to contain any leakage into the ramp from the potential water-bearing structures. This method, unlike other potential methods considered for accessing the ore body, allows better control over potential formation water inflows. An LHD loader to truck haulage system will be utilized to move ore and waste from lateral mine development prior to the completion and installation of the permanent Railveyor in the haulage ramp. 13.5.4 Development and Production Schedule The production and development schedules were completed using the Deswik© scheduling module software. The production schedule is based on the rate assumptions shown in Table 13‐13. A delay of 28 days was used before driving on paste backfill or mining adjacent to a paste backfilled stope. These delays account for curing time as well as multiple pours.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 203 | Page The mining operation schedule is based on 365 days/year, 7 days/week, with two 12 hour shifts each day. A production rate of 3,047 tons/d was targeted with a ramp-up to full production as quickly as possible. The schedule timeframe is monthly for the entire life of mine. Primary access ramp and secondary haulage ramp excavation preparation begins upon completion of the box cut excavation on surface. Production stoping begins sixteen months after the start of ramp development, with a production ramp-up period through the following six months, after which the mine and plant are operating at full capacity. Table 13‐13 shows the annual mine production schedule, and Figure 13‐26 shows the mine production schedule colored by year. Table 13‐13: Mine Production Schedule Year Ore Tons (tons) Mined NbO (%) Mined TiO (%) Mined Sc (ppm) Mined Waste Tons (tons) Backfill Volume (ft) Year 0 396,351 Year 1 22,663 1.153 3.33 75.73 919,483 Year 2 491,681 0.786 2.54 65.32 657,959 3,191,046 Year 3 1,194,029 0.770 2.66 66.99 646,590 12,741,436 Year 4 1,247,664 0.771 2.58 60.23 540,800 12,338,948 Year 5 1,232,616 0.767 2.49 63.21 557,650 12,504,055 Year 6 1,193,599 0.744 2.47 65.14 576,777 12,370,694 Year 7 1,210,747 0.744 2.53 69.58 277,252 12,454,386 Year 8 1,133,751 0.789 2.73 63.61 33,508 12,437,151 Year 9 1,177,200 0.733 2.41 62.03 68,466 11,995,000 Year 10 1,214,345 0.772 2.48 70.71 149,448 12,445,117 Year 11 1,172,803 0.743 2.42 70.18 81,576 12,418,233 Year 12 1,176,621 0.762 2.65 69.11 96,378 12,370,014 Year 13 1,163,999 0.784 2.78 71.89 55,943 12,566,035 Year 14 1,159,979 0.741 2.74 76.95 37,909 12,287,642 Year 15 1,159,636 0.763 2.69 73.13 25,221 12,411,519 Year 16 1,175,711 0.732 2.71 77.21 61,118 12,361,373 Year 17 1,197,510 0.721 2.58 72.95 106,387 12,429,481 Year 18 1,184,559 0.751 2.58 73.64 73,191 12,386,938 Year 19 1,186,644 0.748 2.48 73.40 67,671 12,445,413 Year 20 1,172,192 0.753 2.64 70.64 57,481 12,275,126 Year 21 1,163,531 0.739 2.71 69.37 50,346 12,227,143 Year 22 1,115,642 0.822 2.72 77.79 36,848 12,446,536 Year 23 1,155,006 0.804 2.81 73.00 97,671 11,915,615 Year 24 1,107,493 0.815 2.79 71.14 60,499 12,284,901 Year 25 1,155,661 0.781 2.63 70.94 78,175 11,719,351 Year 26 1,181,405 0.761 2.63 67.20 60,017 12,266,487 2 5 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 204 | Page Year Ore Tons (tons) Mined NbO (%) Mined TiO (%) Mined Sc (ppm) Mined Waste Tons (tons) Backfill Volume (ft) Year 27 1,164,560 0.773 2.82 71.78 39,732 12,462,230 Year 28 1,171,849 0.750 2.77 68.11 60,265 12,320,050 Year 29 1,165,828 0.729 2.69 69.07 68,341 12,183,031 Year 30 1,163,315 0.744 2.61 67.03 58,765 12,477,265 Year 31 1,156,476 0.740 2.77 66.50 27,827 12,325,815 Year 32 1,157,871 0.768 2.90 69.08 38,545 12,243,565 Year 33 1,156,848 0.745 2.72 69.32 42,351 12,361,994 Year 34 1,150,141 0.781 2.88 68.26 63,944 12,345,009 Year 35 1,162,321 0.743 2.82 67.08 54,451 12,900,177 Year 36 1,153,279 0.743 2.83 66.74 36,341 12,445,163 Year 37 1,151,331 0.787 2.81 71.45 25,728 12,107,186 Year 38 1,164,743 0.716 2.71 66.09 27,788 12,506,866 Year 39 1,138,302 0.746 2.79 67.82 0 12,103,058 Year 40 910,483 0.802 2.86 70.60 27,351 9,558,283 Year 41 972,938 0.716 2.59 66.37 40,283 10,440,185 Year 42 242,493 0.716 2.71 63.96 0 3,060,371 Year 43 311,007 Totals 45,929,462 0.759 2.68 69.27 6,482,430 483,440,895 Source: Amplify Mine Planning, 2026 2 5 2 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 205 | Page img170397038_112.jpg Source: Amplify Mine Planning, 2026 Figure 13‐26: Mine Production Schedule - Colored by Year 13.6 M INING O PERATIONS 13.6.1 Production Schedule The ore feed to the plant comes primarily from stope production. In aggregate, development drifts contribute less than 3% of the total ore produced over the life of mine. Stopes are mined using the longhole open stoping method with cemented backfill on a primary-secondary stope mining sequence. Individual stope blocks are designed to be 49ft wide, up to 49ft long and oriented roughly parallel to the main stress. Levels are spaced 131ft apart in height, and each stope block has top and bottom access drift called the crosscut (x-cut: 14.8 ft x 17 ft flat back drifts) traversing the middle of the stope. Each crosscut is developed to its’ full extent within each stope before the stope is set up for retreat mining. The majority of ore processed by the plant is sourced from longhole open stoping operations, with development ore contributing less than 3% of the total life-of-mine mill feed. Production stopes are designed as longitudinal longhole stopes measuring approximately 50 ft wide by 50 ft long (15 m by 15 m) and are oriented generally parallel to the principal stress direction to optimize geotechnical stability. Mining levels are vertically spaced at 131 ft (40 m) intervals. Each stope is accessed by upper and lower crosscuts measuring 15 ft × 15 ft (4.5 m × 4.5 m) and associated stope drifts
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 206 | Page measuring 15 ft × 17 ft (4.5 m × 5.2 m). Production drilling is completed from the upper stope access using ITH longhole production drills equipped with 3.0-in (76-mm) diameter drill steel. Initial stope void creation is established through the development of a slot raise using a slot reaming machine producing a 30-in (762-mm) diameter opening. The slot is subsequently expanded through blasting to establish the free face required for production blasting. Mining follows a level-by- level, bottom-up extraction sequence utilizing a primary-secondary stope mining strategy. Following ore extraction, both primary and secondary stopes are backfilled with high-strength cemented paste backfill (CPB) to provide regional ground support and maintain overall mine stability. All production blasting is conducted using bulk emulsion explosives. Stope extraction typically consists of an initial slot expansion blast followed by one or more production blasts to recover the remaining stope inventory. Broken ore is mucked from the lower stope access using a 10.3-yd³ (7.9-m³) battery-electric load- haul-dump (LHD) unit with an 18-tonne (19.8-short-ton) payload capacity and remote-operation capability. Ore is transported by the LHD either directly to an ore pass or to a remuck bay, where required, to optimize stope mucking productivity and minimize the impact of haulage distances on production efficiency. Development ore generated from lateral and vertical mine development activities is recovered and transported through the same material handling system as production ore. Development ore represents less than 3% of the total life-of-mine mill feed and is integrated into the production schedule as available. 13.6.2 Development Lateral development includes interlevel ramps, level accesses, stope accesses, and short connecting drifts for ventilation, water handling, supply storage, and power. The interlevel ramp system is 18 ft wide by 19ftm high at a maximum 15% gradient for the Access ramp and a maxim 18% gradient for the Railveyor®. Level accesses are planned at 18 ft wide by 19 ft high and are mined higher at the remuck bays to allow the haul trucks to be loaded by the LHD. Stope access drifts 14.8 ft wide by 17 ft high. Stope access is oriented perpendicular to the strike of the orebody. The lateral development is sized for the operation of the mining equipment fleet selected for the operation. The development profiles include allowances for ventilation ducting and services 13.6.3 Truck and LHD Haulage The underground material haulage system for the Elk Creek Project combines conventional load-haul-dump (LHD) units and haul trucks during the initial development phase, including an early introduction of the Railveyor™ electric railcar haulage system. This hybrid approach provides operational flexibility during ramp and level development while transitioning to a highly efficient, low-emission primary haulage method during steady-state production. Mobile equipment utilized during early development will consistently of conventional units, with a progressive transition towards electrification as infrastructure and operational requirements evolve. The use of battery-electric equipment is central to the long-term strategy to minimize underground heat load, reduce emissions, and limit ventilation demand, consistent with the overall electrification strategy of the Project. 13.6.3.1 Development Phase Haulage During early ramp and level development, primary muck haulage is performed using 45-tonne haul trucks. Muck is transported from remuck bays or temporary stockpile locations to surface via the service and production ramps. Haulage performance has been evaluated using first-principles cycle-time analysis that incorporates bucket capacity, fill factor, material density (broken), and varying
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 207 | Page haul distances along the ramps. The resulting productivity assumptions are considered appropriate for the mine planning included in this Technical Report Summary. Mucking at the development face is carried out with 8 yd³ LHDs. The 8 yd³ bucket size provides a good match with the 45- tonne (49.6 ton) haul trucks and offers suitable versatility for ramp and crosscut development activities. 13.6.3.2 Transition to Railveyor Haulage As underground development advances, the haulage system progressively transitions from truck-based transport to the Railveyor material-handling system. Initial Railveyor installation is planned at the 210 Level. The first operational Railveyor segment (from the 210 Level to surface) will be commissioned as part of the development program. Once the initial Railveyor segment is operational, ore and waste material will be loaded directly onto Railveyor trains at dedicated underground loading stations, significantly reducing average trucking distances and the number of haul trucks required underground. Truck haulage will remain available as a flexible backup for development activities, waste handling, and any areas not yet served by the Railveyor system. 13.6.3.3 Production Phase Haulage During steady-state production, the Railveyor system becomes the primary underground-to-surface haulage method. Ore and waste from the three main load levels (490L, 690L, and 930L) are transferred to the Railveyor via ore-pass systems equipped with grizzlies, arc gates, and vibratory feeders. The Railveyor operates with five 1,080 ft trains at a nominal capacity of 374 tons per hour, supporting the planned peak production rate. At the production faces, 10 yd³ battery-electric LHDs are utilized to handle ore from stopes and deliver it to the ore passes. Haulage performance for production LHDs has been evaluated using first-principles analysis based on an average tramming distance of approximately 1,000 ft, bucket fill factors, and material density. Based on these assumptions, a fleet of up to three 10 yd³ battery-electric LHDs is expected to be sufficient to support the planned production rate at a level of confidence appropriate for the 2026 Elk Creek Study. The primary access headings (North and South Ramps) remain available throughout the Life-of-Mine to support continued development, excavation of ore and waste passes, transfer bins, and progressive expansion of the Railveyor infrastructure. The haulage system configuration and equipment selections described above are based on the production profiles and equipment productivity assumptions detailed in this Technical Report Summary. Final fleet sizing, Railveyor phasing, and productivity verification will be confirmed during detailed engineering once vendor data, site-specific operating conditions, and early development performance are available. The system is designed to support safe, efficient, and low-emission material movement in compliance with MSHA standards under 30 CFR Part 57, Subpart M (Machinery and Equipment).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 208 | Page 13.6.4 Backfilling 13.6.4.1 Normal Operation The Paste Backfill System operator will coordinate with the Hydrometallurgical Plant, underground operations, and the TSF. During typical operation, the Paste Backfill Plant’s belt conveyor network will direct process waste from the Hydrometallurgical Plant to paste mixers for paste production. When paste backfill is required while the Hydrometallurgical Plant is offline, the system will draw process waste from the Surge Storage Facility (SSF), with the belt conveyor network reconfigured accordingly. SSF capacity will be monitored to ensure that it can absorb excess process waste should the Paste Backfill System unexpectedly go offline. Paste backfill campaigns will be planned and documented in a Backfill Letter. The Backfill Letter will specify the paste mix design, the required quantity of paste backfill, and the destination for paste placement. Before start-up, the operator will complete a pre-operational checklist to confirm the availability of process waste, binder, and water; assess the condition of equipment; and coordinate with the Hydrometallurgical Plant, TSF, and underground supervisors. The Paste Backfill Plant operator must also confirm with the underground supervisor that stope barricades are suitable for retaining paste backfill. Start-up will begin with a pre-flush of the Paste Distribution System (PDS) to provide confirmation that the PDS is correctly configured and sending material to the target destination. This confirmation may be provided by a camera feed at the stopes or by visual observation by workers. Before a planned shutdown, the operator will confirm that the required quantity of paste backfill has been delivered. Once the Paste Backfill Plant ceases paste production, the operator will flush the PDS with water to remove residual paste from the piping 13.6.4.1.1 Paste Backfill Quality Control Paste backfill will be sampled regularly to verify that it meets specification. This will include bleed water testing and UCS testing. For UCS testing, paste will be cast into cylinder molds 50 mm in diameter by 100 mm in height. Each sample set will include six cylinders, with three for 7-day breaks and three for 28-day breaks. For each paste mixer and for each paste mix design, sampling sets will be collected once per 1,000-2,000 yd³ of paste produced, or once per 12-hour shift, whichever occurs first. For every 50,000 yd³ of a given paste mix design placed, one set of UCS cylinders will be sent to a third-party laboratory for testing. Slump testing will be performed hourly to confirm that the paste meets slump and slump flow specifications. 13.6.4.2 Upset Conditions In the event of a power outage during paste production, the system will cease operation. The operator will assess whether critical equipment has shut down safely. Selected equipment will be connected to backup power to facilitate the clearing of paste from the system to prevent it from setting. This equipment will include the flush pump to clear the PDS, sump pumps to collect paste discharged from the paste mixers and paste hoppers, the wastewater tank’s agitator and pumps, and PDS diverter valves. In the event of a blockage in the PDS, paste operations will be immediately suspended to prevent additional material from building up and to reduce potential damage to the system. The operator must notify the Hydrometallurgical Plant supervisor and the relevant underground or TSF supervisor
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 209 | Page of the blockage and determine the location of the blockage. The operator will assess whether the blockage can be cleared by controlled flushing. If flushing is unsuccessful or unfeasible, the contents of the PDS may be discharged by a remotely actuated valve. Once the PDS is cleared, it must undergo a flushing sequence followed by the standard start-up procedure before operations resume. 13.6.5 Ground Support Refer to Section 13.2.2.6 for detailed information regarding ground support. 13.6.6 Grade Control and Reconciliation Grade control is an integral component of the long-hole stoping mining method at the Elk Creek Project. It provides confirmation of in-situ grade and tonnage ahead of extraction, supports short-term production scheduling, and enables ongoing validation of the resource block model against actual mining results. Production core drilling is conducted in advance of each production face, aligned to the planned stope geometry, to confirm grade continuity and domain boundaries prior to blasting and extraction. In the 2026 Elk Creek Study, the Elk Creek Project has incorporated a three-stage reconciliation framework into the mine design and production schedule. Reconciliation is planned to compare (1) the long-term resource block model, (2) the short- term production (grade control) block model informed by production drilling, and (3) production actuals derived from mined tons and mill/plant feed grades. Differences between these stages are planned to be tracked on a stope by stope basis to identify systematic bias, informing ongoing calibration of estimation parameters. All detailed reconciliation procedures, sampling protocols, and acceptance criteria remain to be developed during subsequent detailed engineering. The grade control strategy described is considered appropriate to support the selected long-hole stoping method and production reporting requirements, with no material technical constraints identified that would prevent the Project development or operation. 13.7 V ENTILATION The Elk Creek deposit comprises a large, near-vertical, tabular orebody. Production levels are spaced at ~131 ft (40 m) vertical intervals (sill-to-sill) across a total vertical mining span of approximately ~2,230 ft (680 m). The proposed mine layout employs a dual-ramp configuration developed from a single box cut, with each ramp terminating at its own portal. The uppermost production horizon is the 210 Level, situated approximately ~689 ft (210 m) below surface. The two ramps are designated as follows: • Ramp 1 – Personnel and Equipment Access. This ramp is dedicated to the transport of personnel, equipment, and materials. It is developed to dimensions of ~18 ft (5.5 m) wide by ~19 ft (5.8 m) high at a maximum gradient of 15%. • Ramp 2 – Railveyor® Haulage System. This ramp accommodates the Railveyor® haulage system and is developed to the same dimensions, ~18 ft (5.5 m) wide × ~19 ft (5.8 m) high, but at a steeper gradient of up to 18%. The Railveyor system services dedicated ore and waste bin infrastructure at the 490 Level, 690 Level, and 930 Level loading points. All remaining capital development, including footwall drifts and crosscuts (draw points), is constructed to dimensions of ~14.8 ft (4.5 m) high by ~14.8 ft (4.5 m) wide.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 210 | Page The mine ventilation system is designed as a simple, unidirectional circuit. Fresh air is supplied via Ramp 1 (personnel and equipment access) and exhausted via Ramp 2 (Railveyor® decline). This configuration forms the foundation of the overall ventilation network, which has been developed using numerical modelling (VentSim) to ensure adequate airflow distribution, heat management, and air quality throughout the mine life. Return air is routed through the Railveyor decline, with split louver regulators on each level providing precise airflow control. A schematic of the proposed overall mine ventilation layout is illustrated in Figure 13‐27. Source: Dumas 2026 Figure 13‐27: Current Overall Mine Ventilation Layout Owing to the selection of battery-electric mobile equipment and the Railveyor® haulage system, diesel particulate matter and exhaust emissions are eliminated from the ventilation design basis. Airflow requirements are therefore governed by worker comfort, heat dissipation, and velocity criteria rather than regulatory diesel standards. The system is engineered as a positive- pressure (“push”) ventilation network, with surface facilities providing conditioned intake air to address the humid continental climate of southeast Nebraska (hot, humid summers and cold winters). Detailed airflow quantities, fan configurations, auxiliary ventilation, refrigeration, heating, and control philosophy are presented in subsequent sections of this report. 13.8 A IRFLOW R EQUIREMENTS The selection of battery-electric mobile equipment and a Railveyor® haulage system have eliminated diesel particulate matter and exhaust emissions from the ventilation design basis. This has allowed
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 211 | Page the ventilation system to focus on providing adequate air movement for worker comfort, heat dissipation, and maintenance of overall air quality throughout the underground workings. Consequently, airflow requirements for the Elk Creek Mine are determined solely on the basis of minimum and maximum air velocity criteria established in the Ventilation Design Criteria, rather than regulatory diesel ventilation standards. Ventilation simulation modelling (VentSim) has been performed for both the development phase and the life-of-mine (LoM) steady-state peak production scenario to quantify the required airflow quantities and confirm distribution throughout the ramp, drift, and production horizons. The LoM steady-state model establishes a total underground airflow requirement of 240 m³/s (508,531 CFM), inclusive of modelled leakage and autocompression. This quantity represents the maximum design airflow demand and defines the duty for the surface intake fans and associated conditioning plant. A detailed breakdown of airflow by activity (development and production zones), heading type, support facilities (shops), and velocity-based allocation is provided in Table 13‐14.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 212 | Page Table 13‐14: Airflow Determination TOTAL U/G Airflow Required Steady State Activity Quan tity Po wer (hp ) Tot al Po wer (hp ) Tot al Po wer (k W) Velo city Ar ea Volu me (headi ng) Volu me (m3/ s Tota l) Volu me (CF M Tota l) Development Mid Zone Jumbo 1 Dev area 8 yard LHD Bolter Truck TH550B No. of Dev. Faces @ 5.5 m x 5.8 m 1 0.75 31. 9 24 1.15 28 28 5829 8 Lower Zone Jumbo 1 Dev Area 8 yard LHD Bolter Truck TH550B No. of Dev. Faces @ 5.5 m x 5.8 m 1 0.75 31. 9 24 1.15 28 28 5829 8 Production Mid Zone - 5 level plus loading Jumbo 1 Prod 8 yard LHD 1 Main Heading Bolter 1 Secondary Heading No. of Production Areas @ 4.5 m x 4.5 m 1 1 20. 25 20
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 213 | Page TOTAL U/G Airflow Required Steady State Activity Quan tity Po wer (hp ) Tot al Po wer (hp ) Tot al Po wer (k W) Velo city Ar ea Volu me (headi ng) Volu me (m3/ s Tota l) Volu me (CF M Tota l) Only 4 LH518iB 10 yard total No. of Main Headings @ 4.5 m x 4.5 m 1 0.5 20. 25 10 No. of Secondary Headings @ 4.5 m x 4.5 m 1 0.25 20. 25 5 35 35 7508 8 Lower Zone - 7 level plus loading Jumbo 3 Prod 8 yard LHD 2 Main Heading Bolter 1 Secondary Heading No. of Production Areas @ 4.5 m x 4.5 m 3 1 20. 25 61 Only 4 LH518iB 10 yard total No. of Main Headings @ 4.5 m x 4.5 m 1 0.5 20. 25 10 No. of Secondary Headings @ 4.5 m x 4.5 m 1 0.25 20. 25 5 76 76 1609 02 Air Velocity Min Secondary Headings 0.25 m/s (50 ft/min) Drift size 4.5 x 4.5 1 0.25 20. 25 5.06 Main Heading 0.5 m/s (100 ft/min) Drift size 4.5 x 4.5 1 0.5 20. 25 10.13 Production 1.0 m/s (200 ft/min) Drift size 4.5 x 4.5 1 1 20. 25 20.25 Developme nt 0.75 m/s (150 ft/min) Drift size 5.5 x 5.8 1 0.75 31. 9 23.93 Shops 0.75 m/s (150 ft/min) Drift size 5.5 x 5.8 1 0.75 31. 9 23.93 Summary Dev Areas Upper 0 0 0
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 214 | Page TOTAL U/G Airflow Required Steady State Activity Quan tity Po wer (hp ) Tot al Po wer (hp ) Tot al Po wer (k W) Velo city Ar ea Volu me (headi ng) Volu me (m3/ s Tota l) Volu me (CF M Tota l) Dev Areas Lower 0 0 0 Production Areas Mid Zone 1 35 7508 8 Production Areas Lower Zone 1 76 1609 02 Main Shop 1 24 5069 4 Sat Shop 1 24 5069 4 0 Subtotal 159 337,3 79 Modeled Leakage and Autocompression (actual) 81 171,6 29 Total Underground Volume Requirement 240 508,5 31 Source: Dumas 2026 Production 4 Main Heading Development 0 Main Headings 2 Secondary Headings 2 8
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 215 | Page More detailed velocity limits, dust mitigation measures, numerical modelling results, and the integration of auxiliary ventilation are addressed in subsequent sections of this report. The airflow quantities established here form the design basis for the surface fresh-air intake system, which is sized to deliver approximately 509,000 CFM of conditioned air under peak LoM conditions. 13.8.1 Ventilation Controls The ventilation control system for the Elk Creek underground mine has been developed to provide integrated, automated management of airflow distribution, fan operation, auxiliary ventilation, and environmental monitoring. The system ensures safe working conditions, optimizes energy consumption, and maintains compliance with regulatory requirements while supporting the unidirectional ventilation circuit described in prior sections. Complete control and monitoring of all ventilation and cooling parameters are available from the Operations Control Center (OCC) or any Human Machine Interface (HMI) connected to the Process Control Network (PCN). The architecture also supports management through the VentSim™ Control Ventilation on Demand (VOD) system. Further refinement of control logic, hardware selection, and hazard reviews will occur during detailed engineering. 13.8.1.1 Ventilation on Demand (VOD) A Ventilation on Demand (VOD) system forms the core of the automated airflow management strategy. The VOD system utilizes real-time data from the PCN to automatically allocate sufficient ventilation throughout the mine to maintain safe working conditions. It can operate in fixed-speed mode, be scheduled to ramp up or down at shift changes or dynamically adjust based on measured flow requirements. The level of automation is user-selectable, ranging from manual control (Level 1) to advanced control strategies that optimize airflow distribution (Level 5). Level 4 incorporates vehicle tracking data to determine and control flow setpoints. These automation levels, adapted from industry-standard VOD frameworks, enable progressive implementation of demand-driven ventilation while preserving operational flexibility. The VOD package will be vendor-supplied, with final integration details confirmed during detailed design. 13.8.1.2 Surface Intake Fans The main surface intake fans operate in flow-control mode. Fan speed is automatically adjusted via variable frequency drives (VFDs) to maintain the required total airflow into Ramp 1. This mode supports production targets while minimizing power consumption and ensuring that underground heat loads and contaminant levels remain within design limits. 13.8.1.3 Auxiliary Fans Auxiliary fans and associated ducting deliver fresh air to development headings, production areas, and infrastructure locations. These fans are controlled remotely through the HMI or automatically through the VOD system. On/off commands may be issued manually by the ventilation engineer or executed automatically by the VOD system based on equipment and personnel presence (via scheduling, tracking data, or direct commands). Each auxiliary fan includes local start/stop buttons, remote HMI control, and full integration with VOD for remote and automatic operation. Starters are located at the nearest electrical substation and communicate directly with the PCN, allowing real-time status visibility on OCC HMIs and field devices (tablets or Wi-Fi/LTE-enabled interfaces).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 216 | Page 13.8.1.4 Monitoring and Control Infrastructure Level-specific ventilation control is achieved through Air Monitoring Stations (AMSs) installed in close proximity to regulators at each mining level exit and major access points to the Railveyor haulage ramps. Each AMS includes an air flow meter, wet-bulb globe temperature compound instrument (relative humidity, barometric pressure, and dry-bulb temperature), carbon monoxide and nitrogen dioxide sensors, two electrically actuated louvers forming a split/door-type regulator, differential pressure measurement across the regulator, and regulator position feedback. The AMS flow and temperature cascade controller actuates the regulator to maintain minimum flow and maximum temperature setpoints established by the ventilation engineer or VOD system. Active and inactive levels are dynamically identified within the control system. In the event that temperature setpoints cannot be met at a level, the refrigeration plant setpoint is adjusted to deliver cooler intake air where possible. Excess airflow is managed by ramping down the refrigeration plant to raise outlet temperature toward the design setpoint. Air Quality Stations (AQSs) provide supplementary monitoring at every level access and major decline/ramp fresh-air route (primarily on the intake side, with selected exhaust-side installations during early development). Each AQS is equipped with an air flow meter, dust (opacity) analyzer, carbon monoxide sensors, and a wet-bulb globe temperature compound instrument. Alarms are generated for dust, carbon monoxide, temperature, and low-flow conditions. All monitoring and control data are routed through local Remote I/O (RIO) panels to the PCN, ensuring full visibility on mine HMIs, the OCC, and the VOD system. This architecture supports real-time decision-making, automated response to changing conditions, and compliance with modern mine ventilation standards for continuous environmental oversight. Detailed alarm setpoints, interlocks, and control sequences for the surface cooling plant and heating systems are addressed in subsequent sections of this report. 13.8.2 Ventilation Model 13.8.2.1 Ventilation Numerical Modelling Two modelling stages were evaluated using VentSim Version 6.0: a development scenario extending to the 210 Level, and a Life-of-Mine (LoM) steady-state model documented in the file “Niocorp_IFU_20251117.vsm.” VentSim is an industry- standard three-dimensional mine ventilation simulation software employed globally for the analysis of airflow distribution, pressure losses, heat transfer, gas concentrations, and climatic conditions in underground mining operations. The LoM model represents mine conditions during the steady-state peak production period. This scenario captures the combined effects of the furthest extent of the ventilation infrastructure and the highest total airflow demand, thereby defining the maximum fan duty requirements. There is limited potential to increase airflow throughout the mine without enlarging excavation dimensions, which would result in higher capital development costs. Consequently, the total airflow rate is considered fixed. With the airflow rate established, the capacity of the ventilation system to remove heat from the underground workings is constrained. As a result, heat load becomes a primary driver of the overall mine energy demand, and climatic modelling has determined that the installation of a surface cooling plant is recommended.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 217 | Page Source: Dumas, 2026 Figure 13‐28: Stage 1 Development to 210 Level
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 218 | Page Source: Dumas, 2026 Figure 13‐29: Life-of-Mine (LoM) Stage The ventilation modelling results provide the technical foundation for the detailed design of the surface intake fans, auxiliary ventilation network, and climate-control infrastructure. These models ensure that both the early development phase and the full production phase can be ventilated safely and efficiently while highlighting the critical role of heat management in the overall mine energy balance. More detailed results, including airflow distribution, pressure profiles, and auxiliary ventilation requirements, are presented in subsequent sections of this report. 13.8.3 Ventilation Equipment 13.8.3.1 Main Surface Ventilation The mine ventilation system is designed as a positive-pressure (“push”) system capable of delivering up to 240 m³/s (~508,000 cfm) of conditioned fresh air to the underground workings. Return air flows through the Railveyor decline, which connects directly to the ore-zone exit on each production level. Split louver regulators installed at each level provide precise control of airflow distribution throughout the mine, enabling balanced ventilation to meet varying production demands while minimizing short-circuiting and maintaining design velocities.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 219 | Page The main ventilation system comprises the following key surface installations: • Main fresh-air supply fans, direct-fired natural-gas mine-air heaters, and bulk-air coolers. • Variable-frequency drives (VFDs) on all primary fans to provide operational flexibility in air-volume capacity and to allow real-time adjustment to changing production requirements. Figure 13‐30 illustrates a typical parallel-fan installation, consisting of a refrigeration system, a direct-fired natural-gas mine- air heater, a fan, and an evase. The parallel configuration employs Howden 9250-AMF-6100 full-bladed, 1,000 HP (~745 kW) vane-axial fans. Each branch is equipped with a 4 MW (~13.5 MMBTU/hr) direct-fired natural-gas mine-air heater and 3,000 kWR (~853 RT) of refrigeration capacity. This arrangement ensures redundancy, high efficiency, and the ability to deliver conditioned intake air under the full range of seasonal climatic conditions encountered at the Elk Creek site. The main fan configuration is typical parallel installation showing refrigeration plant, direct-fired heater, Howden vane-axial fan, and evase; after Jodouin Mine Ventilation Ltd., 2026. Source: Dumas, 2026 Figure 13‐30: Main Fan Configuration This surface ventilation infrastructure forms the primary air-supply pathway for the unidirectional circuit, integrating seamlessly with the Ventilation on Demand (VOD) control system described in Section 16.9. Detailed specifications for the refrigeration plant, heating system, and associated electrical and control interfaces are presented in subsequent sections. 13.8.3.2 Auxiliary Ventilation Auxiliary ventilation systems are employed throughout the Elk Creek underground mine to deliver fresh air to development headings, crosscuts, draw points, ore and waste passes, and various underground infrastructure locations that are not adequately served by the primary ventilation
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 220 | Page circuit. These localized systems consist of vane-axial auxiliary fans connected to PVC ducting, sized to overcome frictional losses and leakage while maintaining the required airflow quantities and velocities at the working faces and enclosed areas. All auxiliary fans are fully integrated with the mine’s Ventilation on Demand (VOD) control system, enabling remote start/stop capability and automatic operation based on equipment and personnel presence. This integration supports efficient ventilation management, energy optimization, and compliance with air-quality and climatic criteria. 13.8.3.3 Development Headings Development headings are excavated to dimensions of ~18 ft (5.5 m) wide by ~19 ft (5.8 m) high. Given ventilation lengths often exceeding ~3,280 ft (1 km) and the resulting high frictional pressure drops, twin ~1,219 mm (48-inch) PVC ducts are utilized in conjunction with 54-inch (~1,372 mm), 100 HP (~75 kW) Howden 5400-VAX-2700 fans. This configuration delivers approximately 40 m³/s (~86,000 cfm) at the face. The fans are installed in a staggered arrangement within the airway to minimize the extent of slashing required while optimizing airflow distribution. 13.8.3.4 Crosscut (Draw Points) and Ore/Waste Pass Ventilation Crosscuts and draw points are developed to ~14.8 ft × 14.8 ft (4.5 m × 4.5 m) dimensions. To achieve the minimum required air velocity of ~100 fpm (0.5 m/s), 32-inch (~813 mm), 100 HP (~75 kW) Howden 3200-VAX-2100 fans connected to 36- inch (~914 mm) ducting are specified. These fans are sized to deliver ~22,000 cfm (10.5 m³/s) while accounting for typical duct leakage. 13.8.3.5 Substations, Sumps, and Refuge Station Ventilation Substations, sumps, and refuge stations, also excavated to ~14.8 ft × 14.8 ft (4.5 m × 4.5 m) dimensions, are ventilated using 24-inch (~610 mm), 3 HP (~2.2 kW) Howden 2400-VAX-1800 fans with 24-inch (~610 mm) ducting to provide the required ~4,200 cfm (2 m³/s) of fresh air. 13.8.3.6 Railveyor Loadout Ventilation The Railveyor loadout areas utilize 36-inch (~914 mm) auxiliary ventilation ducting to maintain the necessary clearance above the Railveyor assembly (minimum 74 inches (~1,880 mm) from the top of the drift) while minimizing frictional pressure losses. Appropriate fan selections and duct configurations are provided for the temporary development at the 210 Level and the permanent loading levels at the 490L, 690L, and 930L to satisfy the specific airflow and velocity requirements at each location. The auxiliary ventilation design ensures reliable fresh-air delivery to localized work areas, complementing the main surface ventilation system and supporting safe, productive operations across all phases of mine development and production. Detailed fan performance curves, pressure-volume calculations, and integration with the overall control philosophy are addressed in subsequent sections of this report. 13.8.4 Recommended Ventilation Infrastructure JMVL compiled a list to estimate the required quantity and locations of ventilation controls such as fans, bulkheads, large equipment air doors, man doors, and regulators. For this exercise, the Life-of-Mine (LoM) ventilation model was examined level-by-level to count required ventilation infrastructure. A summary of the required ventilation infrastructure is provided in Table 13‐15 (Infrastructure Matrix).
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 221 | Page Table 13‐15: Ventilation Infrastructure Matrix Level New Crosscut Fans Reused Crosscut Fans Typical Aux Duct Length to Face 36" Duct Length Sumps / Slurry Pumps 24" Duct Length Sump Fans Elec Fans 24" Duct Length Elec Sub Fans Charging Stations 24" Duct Length Charging Station Fans Ore/Was te Feed Conveyo r 24" Duct Length Conveyo r Fans Refuge Station QTY QTY FT FT QTY FT QTY QTY FT QTY QTY FT QTY QTY FT QTY QTY Surface 0 0 0 0 2 164 2 5 410 5 0 0 0 0 0 0 0 210L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 250L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 290L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 330L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 370L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 450L 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 490L 6 0 0 0 1 82 1 0 0 0 0 0 0 0 0 0 0 530L 6 0 0 0 1 82 1 1 82 1 0 0 0 0 0 0 0 570L 6 0 0 0 0 0 0 1 82 1 0 0 0 0 0 0 0 610L 0 6 492 2953 1 82 1 1 82 1 1 82 1 0 0 0 0 650L 0 6 1312 7874 2 164 2 1 82 1 1 82 1 0 0 0 1 690L 0 6 1115 6693 0 0 0 1 82 1 0 0 0 0 0 0 0 730L 0 6 820 4921 0 0 0 1 82 1 0 0 0 0 0 0 1 770L 0 6 1230 7382 0 0 0 1 82 1 0 0 0 0 0 0 0 810L 0 6 984 5906 0 0 0 1 82 1 0 0 0 0 0 0 0 850L 0 6 656 3937 0 0 0 1 82 1 1 82 1 0 0 0 0 890L 0 6 820 4921 2 164 2 1 82 1 1 82 1 1 82 1 0 930L 0 6 558 3346 1 82 1 1 82 1 0 0 0 0 0 0 0 Level 24" Duct Length Refuge Fans Loadout Fan Power 36" Loadout Ducting Length Ore/Was te Pass Fan 36" Duct Length Ore/Was te Pass Fan Intake Fans 9250- AMF- 6100 Heaters Bulk Air Coolers Condens er Cooling Towers Chillers (3.5 MWR) Evap and Cond Pumps Regulato rs Bulkhea ds Personne l Door Airlock Door FT QTY kW FT QTY QTY QTY QTY QTY QTY QTY QTY QTY QTY QTY QTY QTY Surface 0 0 0 0 0 0 0 2 2 2 2 2 4 0 2 2 2 210L 0 0 13 656 0 0 0 0 0 0 0 0 0 1 1 2 2 250L 0 0 0 0 1 50 1 0 0 0 0 0 0 2 2 1 0 290L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 330L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 370L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 450L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 490L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 530L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 570L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 610L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 650L 25 1 40 1841 1 50 1 0 0 0 0 0 0 1 1 1 0 690L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 730L 25 1 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 770L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 810L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 850L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 890L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 930L 0 0 0 0 1 50 1 0 0 0 0 0 0 1 1 1 0 Source: Dumas, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 222 | Page The infrastructure comprises auxiliary fans of various diameters and power ratings with associated PVC ducting to supply fresh air to development headings, crosscuts and draw points, Railveyor loadout facilities, substations, sumps, and refuge stations. Split louver regulators are specified at strategic locations to enable precise regulation of airflow to individual mining levels. Large equipment air doors, man doors, and bulkheads are incorporated to direct airflow, provide isolation, and maintain the integrity of the unidirectional ventilation circuit. This infrastructure is fully integrated with the main surface ventilation system (Section 13.8.3.1) and the auxiliary ventilation network (Section 13.8.3.2). It supports the Ventilation on Demand (VOD) control philosophy (Section 13.8), ensuring reliable delivery of conditioned air to active working areas while minimizing short-circuiting, maintaining design velocities, and facilitating effective heat and contaminant management. The quantities and locations identified in the Infrastructure Matrix provide the basis for procurement, detailed design, and installation planning, with final configuration to be confirmed during detailed engineering. The recommended ventilation infrastructure ensures compliance with safety and operational requirements across all phases of mine development and production, consistent with industry best practices for underground hard-rock mines. 13.8.5 Ventilation Power Consumption The Life-of-Mine (LoM) ventilation scenario was evaluated in accordance with the detailed numerical modeling and infrastructure requirements presented in the Mine Ventilation Design Report prepared by Jodouin Mine Ventilation Ltd. (February 2026). This assessment accounts for all operating primary and auxiliary fans, direct-fired mine-air heaters, the surface refrigeration plant, condenser cooling towers, and associated pumps operating under steady-state peak-production conditions. The electrical consumption of the refrigeration plant is based on an equivalent of three months of full-load operation per year to reflect seasonal cooling requirements in the Nebraska climate. The ventilation system is projected to have an instantaneous power demand of 10 MW, corresponding to an annual electrical energy consumption of approximately 78 GWh. At a revised electricity rate of US$0.0918/kWh (as of March 2026), the total annual electricity cost for the ventilation systems included in this scope is estimated at US$7.16 million. This figure comprises the following components: • Sump fans: US$11,286/yr • Electrical substation fans: US$18,059/yr • Charging station fans: US$4,514/yr • Conveyor fans: US$1,129/yr • Refuge station fans: US$2,257/yr • Loadout fans: US$86,851/yr • Ore and waste pass fans: US$180,939/yr • Primary intake fans: US$1,414,141/yr • Heaters (electricity portion only): US$105,754/yr (natural-gas costs excluded) • Bulk air coolers: US$0/yr • Condenser cooling towers: US$19,829/yr • Chillers: US$213,541/yr • Chiller pumps: US$63,887/yr
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 223 | Page These estimates are derived from the LoM steady-state model and reflect the unidirectional push-ventilation system design, including variable-frequency drives on primary fans and auxiliary ventilation for development, production, and service areas. Actual operating costs will be subject to final equipment selection, site-specific energy tariffs, maintenance practices, and realized production schedules. The values presented herein are suitable for this level of mine planning and are consistent with the ventilation design criteria established for the Elk Creek Project. 13.8.6 Mine Air Heating Heat inputs for the ventilation numerical model were developed in accordance with the Mine Ventilation Design Report prepared by Jodouin Mine Ventilation Ltd. (February 2026) to support the determination of both mine air heating and cooling requirements for the Elk Creek Project. These inputs form the basis for climatic modeling that establishes the required capacity of the surface direct-fired natural gas mine-air heaters. 13.8.6.1 Primary Equipment Heat Heat generation was modeled based on primary mining equipment, including load-haul-dump (LHD) units, longhole drills, jumbo drills, secondary breakage equipment, and bolters. For the Life-of-Mine (LoM) scenario, a single truck was modeled on the ramp near the intake portal. Heat loads from underground pickup trucks and utility vehicles were combined and positioned at the top of the intake ramp. For the development scenario, two trucks, two LHDs, and two jumbos were modeled at the advancing faces of both the Railveyor ramp and the personnel/equipment ramp. Detailed estimates of heat output from each piece of equipment are summarized in Table 13‐14. 13.8.6.2 Railveyor Heat Loads The total heat output from the 154 Railveyor drive stations was calculated to be 263.28 kW (898,000 BTU/hr). This heat load was uniformly distributed along the 18,674 ft (5,692 m) length of the Railveyor ramp, resulting in a linear heat generation rate of 0.04625 kW/m (0.0141 BTU/hr per ft). 13.8.6.3 Sumps, Substations, Shops, and Refuge Stations Heat loads associated with ancillary excavations (sumps, electrical substations, maintenance shops, and refuge stations) were provided by the respective discipline work packages and incorporated into the model at representative locations. These heat inputs were used in the ventilation and climatic simulations to confirm that the surface mine-air heating system is sized to maintain acceptable underground working temperatures under design winter conditions. The heaters form an integral part of the positive-pressure ventilation system and operate in conjunction with the main intake fans and bulk air coolers. Actual heating requirements will be refined during detailed design based on final equipment selections, production schedules, and site-specific operating data. The values presented are suitable for planning and are consistent with the ventilation design criteria established for the project.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 224 | Page Table 13‐16: Equipment Heat Category Equipment Brand Model Underground Utilization Qty req. Preprod Qty. Production Additional Information User Comments Selected Development Bolter Sandvik DS412iE ☐ 3 3 Electric Contractor x Development Haul Truck Sandvik TH550B ☐ 3 1 Electric Contractor x Development Jumbo Sandvik DD422iE ☐ 3 3 Electric Contractor x Development LHD - 10 YD Sandvik LH518iB ☐ 4 4 Electric Contractor x Development LHD - 2 YD Sandvik LH203 ☐ 1 1 Diesel Contractor Low utilization x Development LHD - 6 YD Sandvik LH410 ☐ 1 1 Diesel Contractor Low utilization x Development Cable bolter Sandvik DS422i ☐ 1 1 Diesel Contractor x Light vehicle UG Pickup - Mechanic Kovatera KT200 ☐ 1 1 Electric Contractor x Light vehicle UG Pickup - Safety Supervision Kovatera KT200 ☐ 1 1 Electric Contractor x Light vehicle UG Pickup - Survey / Engineering Kovatera KT200 ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Electrician Kovatera KM200e Cable Reeler With Scissor Deck ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Explosives transport Kovatera KT200 ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Face cleaning Kovatera KM200e Mine Utility Vehicle c/w fork and lift ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Loading Kovatera KM200e Mine Utility Vehicle c/w basket and anfo ☐ 2 2 Electric Contractor x Light vehicle Utility vehicle – Man carrier Kovatera KT300e Personnel Carriers - Closed Box 2+8 ☐ 2 3 Electric Contractor x Light vehicle Utility vehicle - Mechanic Kovatera KT300e Mobile Mechanical Support w crane ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Mechanic Kovatera KT300e Mobile Mechanical Support w crane ☐ 1 1 Electric Owner x Light vehicle Utility vehicle - Mine RescueKovatera KT300e Mine Rescue - Closed Box ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Service Kovatera KM200e Mine Utility Vehicle c/w fork and backhoe ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Supervision Kovatera KT300e Mine Utility Vehicle - flat deck ☐ 1 1 Electric Contractor x Light vehicle Utility vehicle - Supervision Kovatera KT300e Mine Utility Vehicle ☐ 3 5 Electric Owner x Other SatStat - Fuel Rock-Tech SE90 0F ☐ 1 1 Electric Contractor x Other SatStat - Lube Rock-Tech SE90 0L ☐ 1 1 Electric Contractor x Production Raise bore Epiroc Easer E10SG ☐ 0 1 Electric Contractor x Production Longhole Sandvik DL422iE ☐ 1 3 Electric Contractor x
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 225 | Page Category Equipment Brand Model Underground Utilization Qty req. Preprod Qty. Production Additional Information User Comments Selected Production Secondary breaking drill Sandvik DB331 ☐ 0 1 Diesel Contractor Low utilization x Supporting Boom truck MacLean BTS EV ☐ 1 1 Electric Contractor x Supporting Explosives Loader - Anfo MacLean ACS EV ☐ 1 1 Electric Contractor Development x Supporting Explosives Loader - Emulsion MacLean ECS EV ☐ 1 1 Electric Contractor Production x Supporting Grader MacLean GRS EV ☐ 1 1 Electric Contractor x Supporting Scissor lift MacLean SLS EV ☐ 2 2 Electric Contractor x Supporting Shotcrete Sprayer MacLean SSS EV ☐ 1 1 Electric Contractor x Supporting Transmixer MacLean TMS EV ☐ 1 1 Electric Contractor x Category Equipment Brand Model Max Speed (km/h) Grade Distance Up (m) Distance Down (m) Distance Flat (m) Time Idle (mins) Avg Heat Load (kW) Development Bolter Sandvik DS412iE 5 N/A N/A N/A 400 240 90 Development Haul Truck Sandvik TH550B 15 15% 6000 6000 400 180 253 Development Jumbo Sandvik DD422iE N/A N/A N/A N/A N/A N/A 160 Development LHD - 10 YD Sandvik LH518iB 10 N/A N/A N/A N/A N/A 132 Development LHD - 2 YD Sandvik LH203 10 N/A N/A N/A N/A N/A 46 Development LHD - 6 YD Sandvik LH410 10 N/A N/A N/A N/A N/A 129 Development Cable bolter Sandvik DS422i N/A N/A N/A N/A N/A N/A 75 Light vehicle UG Pickup - Mechanic Kovatera KT200 15 15% 6000 6000 400 240 11 Light vehicle UG Pickup - Safety Supervision Kovatera KT200 15 15% 6000 6000 400 240 11 Light vehicle UG Pickup - Survey / Engineering Kovatera KT200 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Electrician Kovatera KM200e Cable Reeler With Scissor Deck 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Explosives transport Kovatera KT200 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Face cleaning Kovatera KM200e Mine Utility Vehicle c/w fork and lift 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Loading Kovatera KM200e Mine Utility Vehicle c/w basket and anfo 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle – Man carrier Kovatera KT300e Personnel Carriers - Closed Box 2+8 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Mechanic Kovatera KT300e Mobile Mechanical Support w crane 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Mechanic Kovatera KT300e Mobile Mechanical Support w crane 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Mine RescueKovatera KT300e Mine Rescue - Closed Box 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Service Kovatera KM200e Mine Utility Vehicle c/w fork and backhoe 15 15% 6000 6000 400 240 11
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 226 | Page Category Equipment Brand Model Underground Utilization Qty req. Preprod Qty. Production Additional Information User Comments Selected Light vehicle Utility vehicle - Supervision Kovatera KT300e Mine Utility Vehicle - flat deck 15 15% 6000 6000 400 240 11 Light vehicle Utility vehicle - Supervision Kovatera KT300e Mine Utility Vehicle 15 15% 6000 6000 400 240 11 Other SatStat - Fuel Rock-Tech SE90 0F 15 15% 6000 6000 400 240 11 Other SatStat - Lube Rock-Tech SE90 0L 15 15% 6000 6000 400 240 11 Production Raise bore Epiroc Easer E10SG N/A N/A N/A N/A N/A N/A 110 Production Longhole Sandvik DL422iE 5 N/A N/A N/A N/A N/A 160 Production Secondary breaking drill Sandvik DB331 12 N/A N/A N/A 400 240 48 Supporting Boom truck MacLean BTS EV 10 N/A N/A N/A 400 240 29 Supporting Explosives Loader - Anfo MacLean ACS EV 10 N/A N/A N/A 400 240 26 Supporting Explosives Loader - Emulsion MacLean ECS EV 10 N/A N/A N/A 400 240 26 Supporting Grader MacLean GRS EV 5 15% 6000 6000 400 0 38.2 Supporting Scissor lift MacLean SLS EV 10 N/A N/A N/A 400 240 29 Supporting Shotcrete Sprayer MacLean SSS EV 10 N/A N/A N/A 400 240 30 Supporting Transmixer MacLean TMS EV 10 15% 6000 6000 400 0 59.1 Source: Dumas, 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 227 | Page 13.8.7 Thermal Exposure The ventilation and cooling system for the Elk Creek Project has been designed to control thermal exposure and maintain underground workplace ambient conditions within acceptable limits for worker health and safety. Design underground workplace conditions, as established in the Ventilation Design Criteria (Jodouin, 2025), are as follows: • Maximum dry-bulb temperature: ~104°F (40.0°C) • Maximum wet-bulb temperature: ~82.4°F (28.0°C) • Maximum reject Wet-Bulb Globe Temperature (WBGT): ~82.4°F (28.0°C) Refrigeration is incorporated into the ventilation system when wet-bulb temperatures exceed ~80.6°F (27.0°C). Climatic modeling performed using VentSim™ Version 6.0 for both the development stage and the Life-of-Mine (LoM) steady-state scenario, as documented in the Mine Ventilation Design Report (Jodouin, 2026), incorporated all major heat sources, including primary mobile equipment, the Railveyor haulage system, sumps, substations, shops, refuge stations, geothermal heat from the rock mass, and auto-compression effects. The modeling confirmed that a surface refrigeration plant and bulk air coolers are required to manage the combined heat loads under peak summer conditions. The positive-pressure (“push”) ventilation system supplies conditioned air via the personnel and equipment ramp (Ramp 1), ensuring that design thermal limits are maintained at the working faces and throughout the active production areas. The integrated heating, ventilation, and cooling strategy—comprising surface direct-fired natural-gas mine-air heaters for winter operation and the refrigeration plant with bulk air coolers for summer operation—provides effective thermal exposure management across the full vertical mining span of approximately ~2,230 ft (680 m). These engineered controls, together with the unidirectional ventilation circuit and auxiliary ventilation systems, ensure compliance with the specified thermal criteria under both development and full-production conditions. The thermal exposure parameters and associated system capacities are suitable for planning at the level of the 2026 Elk Creek Study. Final verification and refinement of refrigeration loads, control setpoints, and system performance will be completed during detailed engineering based on confirmed equipment selections, production schedules, and site-specific monitoring data. 13.9 M INE I NFRASTRUCTURE AND S ERVICES 13.9.1 Material Handling System The material handling system for the Elk Creek Project consists of a fully electric, automated Railveyor haulage system that transports ore and waste from underground loading stations to surface discharge points. The system comprises underground loading stations, the Railveyor railcar haulage network (including the dedicated Ramp 2), two surface discharge loops (one for ore and one for waste), a surface railcar maintenance facility, and associated track switches, bypass spurs, and control infrastructure. Ore is transferred from the surface stockpile to the crusher circuit by wheel loaders, while waste is stockpiled separately. All components are described in detail in the NioCorp – Elk Creek Project Material Handling Engineering Study (Railveyor Technologies Global Inc., 2026),
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 228 | Page which was prepared specifically for the 2026 Elk Creek Study and is illustrated in the schematic shown in Figure 13‐31. The Railveyor system is a shuttle configuration utilizing lightweight railcars propelled by stationary electric drive stations along a light-gauge track. The system is controlled by a centralized automation platform and is designed to operate continuously and autonomously. The south portal Ramp 2 is dedicated exclusively to the Railveyor and has been developed at an 18% grade with nominal dimensions of ~18 ft (5.5 m) wide by ~19 ft (5.8 m) high. The system has a Life-of-Mine (LoM) capacity of 48.8 million short tons (~44.3 million metric tonnes) of ore and 5.4 million short tons (~4.9 million metric tonnes) of waste. It is sized to sustain a nominal production rate of 5,500 short tons per day (~4,990 metric tonnes per day) based on a 16.2-hour daily operating schedule, with a peak continuous capacity of 340 short tons per hour (~308 metric tonnes per hour) using five trains, each 1,080 ft (~329 m) in length at full mine build-out. The trains are powered by a total of 154 drive stations strategically located along the route to provide the required tractive effort for starting, stopping, and continuous movement under full load. The Railveyor system is installed in a phased manner to align with mine development and production ramp-up. During the development phase, temporary loading points are established at the 210L horizon using mobile feeders (e.g., Terex or equivalent) supplied by haul trucks or LHDs. Production loading occurs at the three primary load levels (490L, 690L, and 930L), each equipped with two ore-pass discharge points (one for ore and one for waste). Ore passes are fitted with 16 in. × 16 in. (~406 mm × 406 mm) grizzlies, arc gates, high-speed vibratory feeders, discharge chutes with scalper bars, and overhead tramp-metal magnets. Weigh scales and light-fence profile monitors downstream of each feeder ensure trains are loaded to design capacity without overloading. Loaded and empty trains pass each other in four automated bypass spurs located along the ramp. Each bypass is equipped with automated track switches that allow the loaded train to remain on the mainline while the empty train diverts to the offset track. On surface, automated track switches direct trains to the appropriate discharge loop (ore or waste). The discharge loops are constructed on engineered earth ramps with retaining walls and elevated steel skid structures. Material is discharged by inverting the train around the loop; the empty train then reverses direction and returns underground. A separate maintenance loop and 40 ft × 100 ft (~12.2 m × 30.5 m) maintenance shop are located west and south of the portal to allow complete trains to be removed from the production circuit for servicing. Each train consists of individual railcars connected by clevis pins and spherical bearings to permit articulation through horizontal and vertical curves and the discharge-loop inversion. Cars are equipped with rubber-lined steel troughs. The lead and trailing cars incorporate rail-sensing instrumentation and communication equipment. Each drive station comprises two 100 hp (~75 kW) AC motors driving gearboxes fitted with commercial truck tires that apply squeeze traction to the sides of the train. Spring-applied/electric-release brakes provide parking and emergency stopping capability. Variable-frequency drives (VFDs) located in electrical control cabinets (ECCs) control the motors, with regenerative braking utilized to reduce energy consumption. System control is achieved through four programmable logic controllers (PLCs) networked via fibre-optic cable. One PLC functions as the master, coordinating all drive stations, track switches, feeders, scales, and safety devices. Operator interface is provided by a SCADA system located in the surface Underground Control Center (UCC). Closed-circuit video (CCTV) cameras at drive stations, switches, load points, and discharge points allow real-time monitoring.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 229 | Page The Railveyor material handling system provides a reliable, low-maintenance, and energy-efficient means of underground-to- surface haulage that is fully integrated with the mine’s phased development schedule and production requirements. The design parameters and capacities summarized above are based on the engineering study completed for the 2026 Elk Creek Study and are suitable for planning purposes. Final system performance will be confirmed during detailed design, procurement, and commissioning once vendor data, site-specific geotechnical conditions, and operating experience are incorporated. Source: Dumas, 2026 Figure 13‐31: Railveyor System Schematic 13.9.2 Mine Dewatering System The mine dewatering system for the Elk Creek Project has been designed to manage both surface precipitation entering the box-cut area and groundwater ingress plus operational water from the underground workings, thereby preventing flooding and maintaining safe, dry operating conditions throughout the Life-of-Mine (LoM). The system comprises surface portal pump stations, temporary mobile underground pump stations, permanent underground pump stations, associated sumps, pipelines, and vertical boreholes. Design parameters and capacities are based on the engineering completed for the 2026 Elk Creek Study. Surface dewatering is provided to intercept and remove precipitation from the box-cut excavation before water can enter the service (Ramp 1) or production (Ramp 2) portals. The portal pump-station capacity is based on the 10-year, 24-hour design storm event for the Tecumseh, Nebraska area (4.71
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 230 | Page in. or ~120 mm of precipitation). The box-cut area of 509,135 ft² (~47,300 m²) generates a peak runoff of 1,040 gpm (~236 m³/h). A settling sump collects runoff and removes solids prior to gravity feeding into a clear-water sump. Four operating submersible pumps (plus one spare) are installed in the clear-water sump and are sized to handle flows up to 1,000 gpm (~227 m³/h). Discharge is routed to the site stormwater management pond for discharge or reuse as process water. The portal and the associated pumping infrastructure are currently under construction and are expected to be completed before project Final Investment Decision (FID). Underground dewatering collects natural groundwater inflow from rock faces together with water introduced by mining and development activities. The combined maximum inflow is estimated at 1,500 gpm (~341 m³/h). The net average inflow consists of 200 gpm (~45 m³/h) of formation water and an additional 200 gpm (~45 m³/h) of water used for mine operations purposes. The groundwater at the Elk Creek site is expected to exhibit moderate to high salinity (brackish character with elevated total dissolved solids, primarily chlorides and sodium), consistent with hydrogeological characterization data for the deposit. In addition, mine water will contain residues from explosives (such as nitrates) and trace machinery oil/hydrocarbons introduced during development and production activities. These constituents are addressed through the dewatering system design, which includes settling sumps for solids and oil separation, followed by transfer to the surface holding pond. Final treatment occurs in the site water-treatment plant, which may incorporate processes such as softening, clarification, multimedia filtration, and reverse osmosis to manage salinity and remove contaminants prior to reuse in process circuits or other site applications. This integrated approach ensures compliance with water quality requirements and supports the project’s zero-discharge objectives. Water is collected in sumps installed along both the service and production ramps. Boreholes convey water from higher-level sumps to the respective pump-station horizons, where it is directed into settling sumps for solids removal. Horizontal transfer pumps then move the clarified water to the main vertical pumping stations. The system incorporates both temporary and permanent pumping infrastructure phased to match mine development: • Temporary Mobile Pump Stations (210 Level and 650 Level): Skid-mounted centrifugal pump stations (six pumps operating in pairs) with 2,640 gal (~10,000 L) integrated tank capacity provide variable flow up to 1,500 gpm (~341 m³/h). These units are deployed as required during early development. Water from the 210 Level station is pumped to surface via pipeline installed in the production ramp. Water from the 650 Level station is pumped to the permanent 450 Level station through a vertical borehole. • Permanent Pump Stations (450 Level and 930 Level): Each station is equipped with four positive-displacement pumps sized for variable flow up to 1,500 gpm (~341 m³/h). o The 450 Level station pumps water to surface: first via vertical borehole to the 210 Level, then continuing up the production ramp pipeline. o The 930 Level station pumps water to the 450 Level station via vertical borehole.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 231 | Page • Bottom-Level (930 Level) Pumping: Submersible pumps located at the lowest mine elevation transfer dirty water to the 930 Level settling sump through a dedicated vertical borehole. All underground water is ultimately delivered to the surface holding pond, where it undergoes treatment in the site water- treatment plant prior to reuse in process circuits. The dewatering design ensures that pump capacities exceed maximum anticipated inflows under both development and full-production scenarios, providing operational flexibility and redundancy. The system parameters summarized above are consistent with the project’s design basis and will be refined during detailed engineering on the basis of final geotechnical data, confirmed inflow measurements, equipment vendor data, and site-specific operating experience. 13.9.3 Compressed Air System The compressed air system for the Elk Creek Project is designed to supply clean, dry, pressurized air to underground workshops, active mining areas, Railveyor loading-station dust-suppression systems, and refuge shelters (as an emergency backup air supply). The system is located in Facility 23, the surface Underground Electrical Maintenance Substation and Compressor Facility, in accordance with the Basis of Design – Electrical Generator Power (Dumas / NioCorp, Rev A, January 2026). Compressed air is generated by two 150 hp air compressors (one operating, one standby) rated to deliver air at 125 psi (862 kPa) with a total system capacity of up to 600 cfm (1,020 m³/h). The compressors are equipped with variable-speed drives (VSDs) to optimize energy efficiency and respond to fluctuating demand. Each unit includes integrated filtration and a refrigerant dryer to condition the air. A dry-air receiver is provided to stabilize system pressure and minimize compressor cycling. Distribution piping is routed down the production ramp (Ramp 2) to serve the underground operations, with temporary piping installed in the service ramp (Ramp 1) during early development. Branch lines are provided at each mine level. Water drains are installed at every level and at all sumps to remove accumulated condensate from the air lines. Point-of-use treatment is provided as follows: • Filter-regulators at refuge stations on the 450, 610, 730, and 850 levels. • Filter-regulators at the Railveyor dust-suppression systems on the 490, 690, and 930 levels. • Filter-regulator-lubricators (and, where required, small local air receivers) at the maintenance shops on the 450 and 650 levels to support pneumatic tools. The compressed air system is fully integrated with the surface facilities and underground infrastructure. The design parameters summarized above are based on engineering appropriate for the 2026 Elk Creek Study. Detailed piping design, pressure-drop calculations, and final equipment selection will be completed during the detailed design phase, incorporating vendor data, confirmed operating requirements, and site-specific conditions. 13.9.4 Underground Water Supply The underground process water supply system for the Elk Creek Project supplies water to underground workshops, active mining areas, Railveyor loading-station dust-suppression systems, foam-type fire suppression systems in the maintenance shops, latrines, and refuge shelters.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 232 | Page Process water is sourced from reclaimed water produced by the surface water treatment plant and supplemented by externally sourced water as required. The system is designed to deliver a supply capacity exceeding 500 gpm (114 m³/h) at a pressure range of 45 to 80 psi (310 to 552 kPa). Distribution piping is installed down the production ramp (Ramp 2) to serve all underground levels, with temporary piping provided in the service ramp (Ramp 1) during early development. Branch lines are provided at each mine level. Pressure- reducing valves are installed at each level to regulate pressure increases resulting from hydrostatic head with depth and to protect equipment and piping infrastructure. The process water system is fully integrated with the surface water management and dewatering facilities. All underground water is ultimately delivered to the surface, treated, and made available for reuse. The design parameters summarized above are based on engineering appropriate for the 2026 Elk Creek Study. Detailed hydraulic calculations, final pipe sizing, pressure-drop analysis, and valve specifications will be completed during detailed design once vendor data, confirmed flow requirements, and site-specific operating conditions are incorporated. 13.9.5 Underground Fuel Storage and Distribution The Elk Creek Project is designed as a highly electrified underground operation utilizing the Railveyor™ electric haulage system and a predominantly battery-electric mobile equipment fleet. Dedicated battery swap, storage, and charging bays are incorporated to support battery-electric vehicles (BEVs) throughout the Life-of-Mine (LoM). To support the project’s battery-electric mobile equipment fleet (including loaders, trucks, drills, bolters, and utility vehicles), dedicated battery swap, storage, and charging bays are provided at strategic underground locations, including proximity to maintenance shops, refuge stations, and key production levels. These facilities are designed to minimize equipment downtime, maintain high fleet availability, and integrate with the underground electrical distribution network. Industry-proven technologies will be incorporated: • Automated battery exchange systems enable fully automated battery exchange in approximately three minutes. The operator remains in the cabin, and the vehicle self-swaps the depleted battery for a fully charged unit without requiring overhead cranes or additional heavy infrastructure. • Flexible opportunity charging infrastructure, including remote charge posts connected up to 948 ft (300 m) from central charging cabinets. This decentralized approach reduces tramming distances, minimizes queuing, and supports mixed-fleet compatibility. • Onboard charging design philosophy, which eliminates the need for extensive stationary charging bays in many applications and provides operational flexibility for production-support duty cycles. Battery bays will include high-power chargers compatible with the selected equipment voltages, battery storage racks, fire detection and suppression systems, spill containment, forced ventilation for thermal management, and appropriate safety interlocks. The layout provides sufficient maneuvering space for safe vehicle access and egress. Charging infrastructure is sized based on equipment duty cycles, production scheduling, and electrical load distribution from the surface substations and underground power distribution system. Regenerative braking energy recovery is utilized where applicable to improve overall energy efficiency.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 233 | Page The BEV charging infrastructure described above supports the project’s overall electrification strategy and phased transition to full battery-electric operations. Detailed bay configurations, charger ratings, number of bays, and battery management protocols will be finalized during detailed engineering once the final BEV fleet composition, duty cycles, and vendor-specific recommendations are confirmed. The design parameters summarized herein are based on engineering suitable for the 2026 Elk Creek Study. 13.9.6 Workshop, Maintenance Bays, and Warehouse The Elk Creek Project includes dedicated underground maintenance workshops at the 450 Level and 650 Level to support the repair, servicing, and maintenance of mobile equipment, as well as the storage of spare parts and consumables. These facilities are sized to accommodate the battery-electric and support-equipment fleet throughout the Life-of-Mine (LoM) and are integrated with the underground electrical distribution, compressed-air, process-water, ventilation, drainage and fire- suppression systems. A temporary surface workshop will be utilized during early development until the underground facilities are commissioned. The 450 Level workshop comprises 12 maintenance bays and includes the following dedicated areas: • Substation and electrical integration area • Office and maintenance supervision space • Warehouse for parts storage • Lube storage and handling facilities • Two heavy repair bays equipped with monorail hoists • Service bay • Heavy repair bay equipped with an overhead bridge crane • Electrical shop • Tire repair bay • Welding and Fabrication Bay • Combined lube and wash bay The 650 Level workshop comprises 9 maintenance bays and includes: • Substation • Warehouse for parts storage • Office space • Lube storage • Service bay • Electrical shop • Heavy repair bay equipped with an overhead bridge crane • Tire repair bay • Combined lube and wash bay Each underground workshop is equipped with a wash bay containing a water and oil separator. The wash bay is located on the downslope side of the facility to capture any water and foam discharged from the foam-type fire-suppression system in the event of a fire. A surface workshop will be constructed and equipped with an overhead bridge crane and sufficient space to service multiple vehicles simultaneously. This facility will also include office space and personnel amenities. The surface workshop will serve as the primary maintenance area during the
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 234 | Page initial development phase and will be decommissioned or repurposed once the underground workshops become operational. The conceptual layouts and functional descriptions are based on assumptions appropriate for the 2026 Elk Creek Study and are considered appropriate to support the planned battery-electric mobile equipment fleet, development sequence, and production profile. Detailed architectural, structural, and equipment specifications will be developed during detailed engineering once final fleet composition, duty cycles and vendor data are confirmed. 13.9.7 Explosives Storage Explosives storage requirements for Elk Creek Project have been evaluated at a level appropriate for the 2026 Elk Creek Study. Facilities are planned to support safe underground development and production blasting while complying with MSHA 30 CFR Part 57 Subpart E, ATF 27 CFR Part 55 Subpart K, and Nebraska Title 272 regulations. Storage concepts incorporate guidance from the MSHA Program Policy Manual and the American Table of Distances. Final designs, locations and operating parameters will be confirmed during detailed engineering. Surface Explosives Storage Surface storage is planned to utilize ATF-equivalent Type 1 or Type 4 magazines located outside active portal and processing areas. Magazine siting is expected to satisfy American Tabel of Distances separation requirements consistent with ATF and MSHA guidance. A cleared safety zone of approximately 25 ft (7.6 m) surrounding each magazine is planned to reduce ignition risk. Magazines are expected to be fire-resistant, weather-resistant, theft resistant, and vandal-resistant, with non-sparking interiors, secure locking, ventilation, grounding, and lightning protection. Separate storage is planned for detonators. Inventory control, housekeeping, and access procedures will follow MSHA and ATF requirements. Exact locations and capacities will be finalized during detailed engineering. Underground Explosives Storage Underground storage is expected to include central magazines and smaller day-use units such as powder chests or portable magazines. Storage locations will be selected in competent or supported ground, positioned away from active blast areas and traffic, and separated from workplaces and other facilities in accordance with MSHA underground storage guidance (approximately 200 ft minimum separation). Detonators and explosives will be stored separately. Underground Storage concepts include restricted quantities, adequate ventilation, housekeeping, non-sparking materials, and routine inspection/inventory procedures. Day-use powder chests or portable units are planned near active faces to minimize transport distances. Inventory will be managed on a just-in-time basis to limit on-site quantities. Safety, Security and Operational Considerations Explosives storage strategies are intended to support safe blasting operations while minimizing on-site inventories through controlled supply and just-in-time delivery. Storage and handling concepts are integrated with the Project’s ventilation, traffic management, access control, and emergency response framework. Hazards will be managed through engineering controls, administrative procedures, training, and regulatory compliance. Detailed procedures and emergency response plans will be developed during detailed engineering.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 235 | Page Engineering Maturity Explosives storage concepts reflect engineering accuracy appropriate for the 2026 Elk Creek Study and are considered sufficient to support evaluation of the Project’s technical and economic viability. No material explosives storage related constraints have been identified. Final magazine designs, capacity, siting, security features, and regulatory submissions will be completed during detailed engineering prior to construction and operation. All parameters are based on planning consistent with the Project’s safety and environmental design criteria. 13.9.8 Refuge Stations The Elk Creek Project incorporates a network of permanent built-in refuge stations and portable refuge chambers to provide safe, breathable environments for underground personnel in the event that immediate egress via the primary escapeways is compromised. The refuge station network consists of two (2) permanent built-in refuge stations and three (3) portable refuge chambers, consistent with the Project cost estimate. Refuge facilities are designed and will be operated in full compliance with Mine Safety and Health Administration (MSHA) mandatory standards for underground metal and nonmetal mines under 30 CFR § 57.11050 (Escapeways and refuges), 30 CFR § 57.11052 (Refuge areas), and 30 CFR § 57.11054 (Communication with refuge stations). Refuges are positioned such that they can be reached within 30 minutes from any workplace. The design follows MSHA Program Policy guidance and industry best practices. Nebraska state oversight of underground mining safety aligns with these federal requirements. The combination of built-in and portable stations, together with the dual ramp escapeway system, provides comprehensive emergency shelter coverage across the mine. Built-in Refuge Station Permanent built-in refuge stations are integrated into the mine infrastructure at strategic locations along the main ramps and production levels. At the current planning stage, stations are located at the 650 Level and 850 Level. These stations are constructed as hardened, airtight rooms or alcoves in competent or supported ground and located off primary travel ways to provide protection from blast effects, fire, smoke and mobile equipment traffic. Each station includes dedicated connections to the underground compressed-air system (including filter-regulators for emergency backup air) and the process-water supply. Typical features include independent ventilation, lighting, sanitation facilities, first-aid supplies, emergency rations, and communication links to the surface Underground Control Center. The built-in stations provide long-duration shelter capability consistent with the project’s escapeway design and are sized to accommodate the expected number of personnel in each mining block consistent with the mine’s emergency response design philosophy. Portable Refuge Stations Portable refuge chambers (also referred to as refuge alternatives) will be deployed during the development phase and in active production areas to supplement the permanent built-in network. These MSHA-approved mobile units are typically steel- constructed chambers equipped with self-contained life-support systems, including breathing-air supply, carbon-dioxide scrubbing, temperature and humidity control, food, water, sanitation, and monitoring equipment. They are designed to provide a minimum 96-hour survival period for a designated number of miners and can be relocated forward with advancing development and production faces. Portable chambers will be positioned to ensure that miners can reach one within 30 minutes from any working place, in
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 236 | Page accordance with 30 CFR § 57.11050(b). They will be maintained, inspected, and tested in accordance with manufacturer recommendations and MSHA guidelines. Integration with Emergency Response and Engineering Maturity Refuge stations form an integral component of the Project’s overall emergency response framework, which includes multiple escapeways, ventilation controls, underground communications, the surface control room, and mine rescue capability. Operational practices include routine inspection, maintenance, testing, and readiness verification of refuge facilities in accordance with regulatory requirements and manufacturer recommendations. Access, signage, and training related to refuge station use are incorporated into workforce training and emergency preparedness programs. Refuge station concepts described in this section reflect engineering accuracy appropriate for the 2026 Elk Creek Study and are considered appropriate to support evaluation of the Project’s technical and operational viability. Final refuge station specifications, capacities, exact locations, life-support configurations, and inspection and maintenance procedures will be completed during detailed engineering and finalized prior to commencement of underground operations in consultation with MSHA. 13.9.9 Surface Electrical Distribution Electrical power for the Elk Creek Project is supplied by a contract power generation facility provided by Liberty, located on the north side of the project site, to the main surface mine substation. From there, power is distributed underground at 13.8 kV to the Underground Electrical Maintenance Substation and Compressor Facility (Facility 23), which serves as the primary surface electrical distribution hub. Facility 23 also supplies power to selected surface facilities, specifically: • Facility 31A – Mine Dry, Underground Control Center, and First Aid Facility • Facility 31B – Railveyor Maintenance Facility • Facility 31C – Battery Charging and Maintenance Facility • Facility 31D – Mine Ventilation Plant The switchgear lineup in Facility 23 is configured in a main-tie-main arrangement. Under normal operating conditions, the tie breaker remains closed, creating a common bus that is segmented into two distribution sections. This configuration provides operational flexibility for maintenance and isolation while ensuring continuity of service during fault conditions and maintaining power to essential loads. Loads have been categorized into two principal sections to support power reliability planning: (1) Safety-Critical and Operational Infrastructure (Section A), and (2) Production, Surface Facilities, and Haulage Systems (Section B). These categories were used to evaluate power continuity requirements during an unplanned utility outage. There will be no dedicated on-site emergency backup generators. For construction, Liberty will provide 6 × 2.5 MW units, with 4 running and 2 on standby. For operations, Liberty will provide 20 × 2.5 MW units, with 16 running at peak load along with 4 on standby. This level of redundancy ensures that standby units can be brought online in 5–6 minutes, eliminating the need for separate backup generators while maintaining continuity of service to critical loads.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 237 | Page Facility 23 distributes power to the underground mine electrical infrastructure via redundant feeders routed through both the service ramp (Ramp 1) and the production ramp (Ramp 2). This dual-path strategy enhances system reliability for critical underground loads. The surface electrical distribution system is described in detail in the Basis of Design – Electrical Power Distribution (Document 4498-BOD-PWR-A-RI, Rev A, January 2026) and is illustrated on the associated single-line diagrams (Drawings 4498-E-840 and 4498-E-841). The design provides a robust, maintainable, and redundant power supply suitable for the full Life-of-Mine (LoM) production schedule. Final equipment ratings, protective relaying, and arc-flash studies will be completed during detailed engineering to incorporate vendor data, site-specific utility coordination, and updated load profiles. The parameters summarized above are based on engineering appropriate for the 2026 Elk Creek Study and are suitable for planning purposes. 13.9.10Underground Electrical Distribution The underground electrical distribution system for the Elk Creek Project is supplied at 13.8 kV from the switchgear lineup located in the surface Underground Electrical Maintenance Substation and Compressor Facility (Facility 23). Facility 23 receives power from the main surface power generation facility, located on the north side of the project site. To ensure continuity of supply to safety-critical underground infrastructure, Facility 23 utilizes a main-tie-main switchgear arrangement. Under normal operation, the tie breaker remains closed, creating a common bus segmented into two distribution sections. This configuration provides operational flexibility for maintenance and fault isolation while maintaining power to essential loads. Power is distributed underground via redundant 13.8 kV feeders routed through both the service ramp (Ramp 1) and the production ramp (Ramp 2). This dual-path strategy enhances system reliability and allows for isolation of sections without interrupting critical underground services. Underground electrical substations step down voltage as required to serve power distribution panels (PDPs), motor control centers (MCCs), lighting panels, and other equipment at standard utilization voltages, including 4,160 V, 480 V, and 208/120 V. Loads are segregated between safety-critical infrastructure (ventilation systems, dewatering pumps, communications networks, and refuge stations) and non-critical production and haulage loads. This segregation supports reliable operation of essential systems during power disruptions. The design incorporates comprehensive grounding, protective relaying and coordination, and power quality management, including active harmonic filters to mitigate the effects of variable-frequency drives (VFDs) used throughout the mine. The underground electrical distribution system is fully described in the Basis of Design – Electrical Power Distribution (Document No. 4498-BOD-PWR-A-RI, Rev A, January 2026) and is illustrated on the project single-line diagrams (Drawings 4498-E-840 through 4498-E-843). As a greenfield project, all underground electrical infrastructure is new and has been designed specifically for the planned production schedule and equipment fleet. Detailed protection and coordination studies, arc-flash hazard analyses, and final equipment sizing will be completed during detailed engineering. The design parameters and configuration summarized above are based on engineering appropriate for the 2026 Elk Creek Study and are appropriate for planning purposes.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 238 | Page 13.9.11Electrical Buried Services Distribution The surface electrical buried services distribution system for the Elk Creek Project provides reliable, protected power delivery between the main mine substation, Facility 23 (Underground Electrical Maintenance Substation and Compressor Facility), and the other surface facilities (Facility 31A – Mine Dry/Underground Control Center/First Aid; Facility 31B – Railveyor Maintenance; Facility 31C – Battery Charging & Maintenance; and Facility 31D – Mine Ventilation Plant). The system consists of underground duct banks, cable trenches, and direct-buried cable runs designed to safeguard conductors from mechanical damage, environmental exposure, and surface activities while maintaining system integrity and operational redundancy. Buried services are routed in dedicated cable trenches and multi-duct concrete-encased duct banks to avoid conflicts with other underground utilities, roads, and surface infrastructure. Cable trenches are detailed in the plan views of the Compressor and Electrical Building (Facility 23) and include provisions for future expansion and maintenance access. Power feeds to the underground ramps enter the portals via buried duct banks, providing dual-path redundancy through both Ramp 1 (service) and Ramp 2 (production). All buried installations are coordinated with the overall site grading and stormwater management plans. The design and installation of buried electrical services comply with the National Electrical Code (NFPA 70), Article 300.5 (Underground Installations) and Table 300.5 (Minimum Cover Requirements), the National Electrical Safety Code (NESC) for utility coordination, and Nebraska state electrical requirements (which adopt the current NEC with state-specific amendments). Burial depths, conduit materials (typically rigid PVC or steel), separation distances, and marking practices follow these standards and MSHA best-practice guidance for surface electrical installations at metal/nonmetal mines (30 CFR Part 57, Subpart T – Electrical). Grounding, surge protection, and cathodic protection (where required for steel conduits) are incorporated to mitigate corrosion and fault hazards in the Nebraska soil conditions. The buried services distribution system supports the project’s main-tie-main switchgear arrangement in Facility 23, ensuring that critical loads remain supplied during utility outages. As a greenfield project, all buried electrical infrastructure is newly designed and installed. Detailed trench/duct-bank profiles, cable schedules, pull-box locations, and final burial-depth verification will be completed during detailed engineering, incorporating site-specific geotechnical data and final load calculations. The parameters summarized above are based on engineering appropriate for the 2026 Elk Creek Study and are suitable for planning purposes. 13.9.12Development Face Grouting Probe drilling and pre-excavation grouting ahead of the development face are integral components of the ground control and water management strategy for the Elk Creek Project. These measures are implemented during ramp and level advance to identify and seal water-bearing fractures, faults, or weak zones in advance of the working face, thereby minimizing groundwater inflow, maintaining stable ground conditions, and ensuring safe, efficient development. The program is designed in accordance with MSHA mandatory standards under 30 CFR Part 57, Subpart C (Ground Control) and Subpart E (Explosives), as well as best practices outlined in the MSHA Program Policy Manual (Volume IV) and Nebraska state mining guidelines, which adopt federal MSHA requirements for metal and nonmetal underground operations. Probe Drilling
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 239 | Page Probe drilling is conducted from the development face using production drill jumbos or dedicated probe rigs. Holes are drilled 100 to 150 ft (~30 to 46 m) ahead of the face on a pattern that covers the full excavation perimeter plus a safety margin. Drilling parameters, including hole diameter, spacing, and inclination, are adjusted based on real-time geological observations and water inflow data. All probe holes are logged for geology by systematic collection and visual description of rock cuttings returned to the collar at regular intervals (typically every 3 m or 10 ft), supplemented by real-time monitoring of drilling parameters (penetration rate, thrust, torque, and rotation speed) via the jumbo’s on-board instrumentation. These data enable identification of changes in rock type, fracturing, alteration, or hardness. Water pressure and inflow rates are quantified by direct measurement at the collar as drilling progresses. This practice aligns with MSHA recommendations for proactive water control and ground stability during tunnel advance (30 CFR § 57.3401 and related ground control guidelines). Grouting Where probe drilling indicates significant water-bearing zones or unstable ground, systematic pre-excavation grouting is performed. Grout is injected under controlled pressure through packers installed in the probe holes to permeate fractures and create an impermeable curtain ahead of the face. The grouting sequence follows a primary–secondary–tertiary hole pattern to ensure comprehensive coverage. Grout takes are monitored in real time to verify seal effectiveness before excavation resumes. Equipment • Production jumbo drills or dedicated probe drill rigs for probe hole drilling. • High-pressure grout pumps (piston or progressive cavity type) with automated mixing and injection controls. • Mechanical packers and inflatable packers for hole sealing during injection. • Grout mixers, agitators, and delivery lines rated for the required pressures and volumes. Materials Primary grout materials consist of Portland cement-based mixes, supplemented by microfine cement or chemical grouts (e.g., polyurethane or silicate-based) where finer fractures or high-flow conditions are encountered. Accelerators, retarders, and superplasticizers are used as required to control set time and penetration. All materials meet MSHA-approved standards for underground use and are stored in accordance with 30 CFR § 57.6100 (Storage of Explosives and Other Materials) and best- practice guidelines for chemical handling. Resources Grouting operations are performed by specialized crews trained in accordance with 30 CFR Part 48. Materials are procured and stockpiled on surface with just-in-time delivery to the face to minimize inventory. Dedicated water supply and compressed air are provided from the underground utility networks. The program is integrated with the overall development schedule and ventilation plan to maintain air quality during grouting activities. The development face grouting program described above is based on engineering appropriate for the 2026 Elk Creek Study. Final probe patterns, grout mix designs, injection pressures, and performance criteria will be refined during detailed engineering once site-specific geotechnical data from early probe drilling and laboratory testing are available. The measures ensure compliance with
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 240 | Page MSHA and Nebraska regulatory requirements while supporting safe and efficient ramp and level advance to the planned production depths. 13.9.13Dust Suppression System Dust suppression systems are provided at all underground Railveyor loading stations to control airborne dust generated during the transfer of ore and waste material from the ore passes through the vibratory feeders and discharge chutes into the Railveyor trains. Separate dry-fog dust suppression systems are installed at the ore and waste loading locations on the 490 Level, 690 Level, and 930 Level. A dry-fog (ultra-fine mist) system is utilized at each loading station. Strategically placed air-atomizing nozzles are positioned around the material loading chute gates and vibratory feeder discharge points. These nozzles generate water droplets in the 1- to 10-micron range that agglomerate with airborne dust particles, causing them to settle back into the material stream. The dry-fog approach requires significantly less water addition than conventional water-spray systems, thereby minimizing the introduction of moisture into the ore and waste material and reducing potential impacts on material flow and downstream processing. Each system utilizes process water and compressed air supplied from the underground utility distribution networks. Appropriate filtration, pressure regulation, and controls are provided to ensure reliable operation. The dust suppression systems assist in maintaining respirable dust concentrations in compliance with MSHA regulatory requirements for underground metal and nonmetal mines (30 CFR Part 57, Subpart D – Air Quality). The dry-fog dust suppression systems form an integral part of the Railveyor loading station general arrangement (Drawing 4498-G-111) and are described in detail in the NioCorp – Elk Creek Project Material Handling Engineering Study (Railveyor Technologies Global Inc., 2026). The configuration described is based on engineering appropriate for the 2026 Elk Creek Study. Final system sizing, nozzle layout, performance criteria, and integration with the ventilation system will be confirmed during detailed design once vendor data and site-specific operating conditions are incorporated. 13.9.14Communications Systems The communications and surveillance system for the Elk Creek Project is designed to provide reliable, continuous, and MSHA-compliant voice, data, tracking, and video coverage throughout all active underground areas, including the ramps, drifts, stopes, refuge stations, and mobile equipment. The system also supports surface facilities and enables centralized monitoring and control from the Underground Control Center located in Facility 31A. The network architecture consists of a single-mode fibre-optic backbone supplemented by Wi-Fi access points (with LTE as an alternative technology where required) to deliver voice communications, remote equipment operation, real-time personnel and asset tracking, and video surveillance. Coverage is determined by mine geometry and operational requirements, with access points, cameras, and network switches strategically spaced to account for signal attenuation, bends in drifts, and the need for redundancy. Redundant fibre uplink paths are incorporated to eliminate single points of failure. The system is sized to meet minimum bandwidth, latency, and device performance requirements necessary to support remote- operated equipment, fleet management systems, ventilation and dewatering controls, alarm systems, and emergency response communications. Power resilience is
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 241 | Page provided through uninterruptible power supplies (UPS). The communications infrastructure is described in detail in the Basis of Design – Communications & Surveillance (Document No. 4498-BOD-COM-A-RI, Rev A, January 2026) and is illustrated on the Mine Communications Architecture Diagram (Drawing 4498-E-844). As a greenfield project, all communications infrastructure is newly designed and installed. The design satisfies the requirements of 30 CFR Part 57, Subpart T (Electrical – Surface and Underground) and related MSHA Program Policy guidance for underground communications at metal and nonmetal mines. The parameters and configuration summarized above are based on engineering appropriate for the 2026 Elk Creek Study and are suitable for planning purposes. Final system sizing, detailed cable routing, access-point placement, cybersecurity provisions, and integration with the mine automation platform will be completed during detailed engineering once vendor data, confirmed mine layout, and operational procedures are finalized. 13.9.15Safety and Health Safety and health considerations have been integrated into all aspects of the Elk Creek Project mine design, equipment selection, and operating assumptions at a level appropriate for the 2026 Elk Creek Study. The Project will be developed and operated in full compliance with applicable United States federal and state occupational safety and health regulations, primarily those administered by the Mine Safety and Health Administration (MSHA) under 30 CFR Part 57 (Safety and Health Standards – Underground Metal and Nonmetal Mines). Key safety-in-design measures incorporated in the 2026 Elk Creek Study include multiple escapeways, refuge facilities, battery-electric mobile equipment selection to reduce diesel emissions and heat load, ventilation and cooling provisions, ground control measures, and centralized surface control room concept. Principal occupational hazards typical of underground hard-rock mining have been identified and considered in mine planning. Risk management will follow a hierarchy-of-controls approach. A formal Safety and Health Management System, mine rescue capability, detailed emergency response plans, training programs, and ground control standards will be developed during detailed engineering in accordance with MSHA requirements and recognized industry practice. Based on the assessment completed in connection with the 2026 Elk Creek Study, no material safety- or health-related constraints have been identified that would reasonably be expected to prevent development or operation of the Project. Residual risks are typical of underground hard-rock mining and are considered manageable through engineering controls, administrative practices, training, and regulatory compliance. 13.9.16Workforce Workforce requirement for the Elk Creek Project has been estimated based on detailed, role-based Labor loading assessments prepared specifically for the 2026 Elk Creek Study cost estimate. Workforce estimates distinguish between owner-operated (Mine) personnel and contractor personnel and further segregate direct (production, development, and construction) and indirect (management, technical, maintenance and support) roles. Workforce levels are derived from the planned production schedule, mine development rates, selected equipment fleet, and operating philosophy defined at a level appropriate for the 2026 Elk Creek Study. Staffing levels, rotations, and shift structures presented herein represent planning
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 242 | Page assumptions applied in mine scheduling, infrastructure sizing, and operating cost estimation and do not constitute finalized employment or contracting arrangements. The Project is planned to operate under a hybrid owner-operator model, whereby owner-operator personnel provide core management, technical authority, safety, environmental, and key maintenance functions, while contractors perform most of the underground development, construction and production activities. Personnel training and competency assumptions are consistent with Mine Safety and Health Administration (MSHA) requirements under 30CFR Part 48 and are described in Section 13.9.15. The Project does not contemplate construction of an on-site accommodation camp. Workforce accommodation is assumed to be provided through existing housing services, and infrastructure within the regional communities in the vicinity of Elk Creek, consistent with operating practices for mining projects located near established population centers. 13.9.16.1Development Phase Total workforce is estimated at approximately 297 personnel (83 owner-operated +214 contractor). Contractor personnel operate on a 14-days-on / 14-days-off, 12-hour shift rotation. Peak underground personnel on site are estimated at 115-125 persons. 13.9.16.2Full Production Phase Total workforce is estimated at approximately 228 personnel (84 owner-operated + 144 contractor). Peak underground personnel on site are estimated at 95-110 persons. Contractor levels decline as construction activities conclude and steady- state operations commence. 13.9.16.3Direct and Indirect Designations Direct personnel include equipment operators, miners, and blasters engaged in production and development face activities. Indirect personnel include supervisory, technical, maintenance, electrical, automation, logistics, safety, environmental, and administrative roles. Underground construction crews are classified as indirect for the level of planning appropriate for the 2026 Elk Creek Study, as their work is schedule-driven and not directly rate-limiting to production or development advance rates. The 2026 Elk Creek Study cost estimate also includes the allowances for specialized, short-duration construction crews supporting vertical development, ore/waste passes, bins, and phased Railveyor system installation and commissioning. These crews are mobilized on a campaign basis, treated as indirect resources, and are not reflected in permanent site staffing levels. Detailed role breakdowns and quantities supporting the cost estimate are provided in the project labor loading documentation. Actual staffing levels and contractor scopes will be refined during detailed engineering. 13.9.16.4Engineering Maturity and Risk Statement Workforce assumptions reflect engineering accuracy appropriate for the 2026 Elk Creek Study and are consistent with the mine design, development sequence, equipment selection, and automation strategy. No material workforce-related constraints have been identified that would prevent development or operation of the Project. The hybrid owner-operator model with phased contractor support is considered appropriate and achievable. Residual risks, including Labor availability and
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 243 | Page contractor mobilization timing, are typical of underground hard-rock projects and are considered manageable. Final workforce arrangements will be confirmed during detailed engineering and operations planning. 13.9.17Equipment Lateral development for the Elk Creek Project comprises the primary access ramps—the North Ramp, which provides personnel, equipment, and service access, and the South Ramp, which is dedicated to the Railveyor™ haulage system—as well as level access drives, footwall drifts, crosscuts, and other underground mine infrastructure excavations. Excavation cross-section dimensions have been established based on equipment clearance requirements, operational needs, and mine ventilation design, and are considered appropriate for the selected mining method and planned production rate. 13.9.17.1Equipment Strategy and Fleet Basis The underground mining equipment fleet has been sized to support the development and full-production schedules described in Section 16.5. The equipment strategy prioritizes battery-electric equipment to minimize underground emissions, heat load, and ventilation demand, consistent with the Project’s overall electrification strategy. The primary underground-to-surface material handling system is the Railveyor™ electric railcar system, which is fully integrated into the South Ramp design. Limited temporary conventional (diesel-powered) units will be utilized during early development prior to commissioning of permanent charging infrastructure. All mobile and fixed mining equipment is expected to comply with Mine Safety and Health Administration (MSHA) mandatory standards under 30 CFR Part 57, Subpart M, governing machinery guarding, maintenance, and safe operation. Mining equipment regulatory oversight in Nebraska defers to federal MSHA requirements, and no additional state-specific equipment standards are anticipated beyond MSHA approval and certification for underground use 13.9.17.2Underground Haulage and Material Handling The underground material handling system is based on a combination of load–haul–dump (LHD) units, underground haul trucks, and the Railveyor™ system. This approach is expected to provide sufficient operational flexibility during mine development and ramp-up while enabling efficient, predominantly electric material transport during steady-state operations. During early underground development, primary haulage of development muck is planned to be undertaken using 45 t haul trucks transporting material from remuck locations to surface. Haulage performance for ramp development has been assessed using first-principles methods, incorporating assumed bucket capacities, fill factors, material densities, and estimated haulage cycle times over a range of haul distances. The resulting productivity assumptions are considered reasonable for the mine planning included in the 2026 Elk Creek Study. As underground development advances, material haulage is expected to transition progressively from truck-based haulage to the Railveyor™ system, with initial installation planned at the 210 Level. The first Railveyor segment, extending from the 210 Level to surface, is assumed to be installed as part of the development program. Following commissioning of this initial segment, ore and waste material are expected to be transferred directly to the Railveyor using dedicated loading
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 244 | Page arrangements. This transition is anticipated to reduce average trucking distances, limit the required underground haul truck fleet, and improve overall haulage efficiency. Truck haulage is expected to remain available during and after Railveyor commissioning to support ongoing development activities, waste handling, and operational flexibility. The North and South Ramps are assumed to remain the primary access headings to facilitate continued development toward the 490 Level and to support excavation of ore and waste passes, transfer bins, and permanent Railveyor loading infrastructure. These activities are expected to enable staged expansion of the Railveyor system and support ramp-up to steady-state production. 13.9.17.2.1Load-Haul-Dump Equipment During early underground development, 8 yd³ LHDs are planned to be used for mucking and short-distance haulage. This bucket size is compatible with the selected 45 t haul trucks and represents an appropriate balance between productivity and operational versatility for ramp and level development activities. During the production stage, 10 yd³ battery-electric LHDs are planned for ore handling from stopes. Production haulage performance has been assessed using first-principles methods, incorporating assumed bucket capacity, fill factor, material density, and estimated cycle times based on an average haulage distance of approximately 1,000 ft. Based on these assumptions, a fleet of up to three 10 yd³ battery-electric LHDs is expected to be sufficient to support the planned peak production rate at a level of confidence appropriate for the 2026 Elk Creek Study. 13.9.17.2.2Engineering Maturity and Implementation The equipment strategy summarized above is considered suitable for mine planning purposes at this stage of the study. Final fleet composition, battery-electric equipment specifications, MSHA approvals, and productivity confirmation are expected to be completed during detailed engineering and early operations once vendor data and site-specific operating experience are incorporated. All equipment is expected to be maintained in accordance with MSHA Subpart M requirements and manufacturer recommendations to ensure safe and reliable operation throughout the Project life. 13.9.17.2.3Equipment Table A summary of the major mobile equipment planned for the development and pre-production phase and for steady-state production is provided in the accompanying equipment table. The quantities shown represent phased concurrent underground equipment required to support the planned development, ramp-up, and steady-state production schedules in Table 13‐17. Table 13‐17: Underground Equipment Description Brand / Model Project Phases Initial Development Production Ramp Up (3 Fleet) Production Steady state (2 Fleet) Mechanized Bolter 975S 3 0 0 Mechanized Bolter 975 EV 0 3 2 Development Jumbo Boomer 282 3 0 0 Development Jumbo M20 SG 0 3 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 245 | Page Description Brand / Model Project Phases Initial Development Production Ramp Up (3 Fleet) Production Steady state (2 Fleet) LHD - 4YD ST4 1 1 1 LHD - 6 YD R1600 1 0 0 LHD - 6 YD ST10 G 0 1 1 LHD - 8 YD - Development ST14SG 0 3 2 LHD - 10 YD - Production ST18SG 0 1 3 Haul Truck - Development AD 45 3 3 1 Production drilling rigs Simba E70 SG ITH 1 3 3 Raise bore - Slot E10 SG 1 1 1 Explosives Loader - Anfo AC3 1 0 0 Explosives Loader - Emulsion EC5 EV 0 1 1 Scissor lift SL3 2 0 0 Scissor lift SL5 0 2 2 Boom truck BT3 1 0 0 Boom truck BT5 EV 0 1 1 Shotcrete Sprayer SS3 1 0 0 Shotcrete Sprayer SS5 EV 0 1 1 Trans-mixer TM3 1 0 0 Trans-mixer TM5 EV 0 1 1 Mobile Batch Plant BP EV 0 0 0 Blockholer c/w Auto Explosive ChargerBH3 EV 0 1 1 Fuel Truck FL3 1 0 0 Lube truck FL5 EV 1 1 0 Grader UG 20M 1 0 0 Grader GR5 EV 0 1 1 Häggloader 7HR 1 1 0 Telehandler TH1055 1 1 1 Light utility EV Landcruiser EV 8 8 8 Service tractor c/w fork and lift MM530 EV 2 2 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 246 | Page Source: Dumas, 2026 Notes: (1) Equipment quantities are based on assumptions appropriate for the 2026 Elk Creek Study and reflect peak concurrent operational requirements. (2) Battery-electric equipment is assumed where technically and commercially feasible; limited temporary diesel units may be utilized during early development prior to commissioning of permanent charging infrastructure. (3) Final equipment selection, specifications, and fleet sizes will be confirmed during detailed engineering and early operations.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 247 | Page 14 P ROCESS AND R ECOVERY M ETHODS 14.1 O VERVIEW The processing facility is designed to recover the following products from the Elk Creek Deposit: ferroniobium, scandium oxide, titanium tetrachloride, neodymium/praseodymium oxide, terbium oxide, dysprosium oxide, samarium-europium- gadolinium carbonate (“SEG”) and holmium-erbium-thulium-ytterbium-lutetium-yttrium carbonate. The facility is divided into three plants: a mineral process plant, a hydrometallurgical plant and a pyrometallurgical plant. While both the mineral processing and pyrometallurgical plants are composed of only one area. The hydrometallurgical plant is divided into 9 nine areas as follows: (1) AREA 100 – Ore Activation (2) AREA 200 – Ammonium Chloride Cycle (3) AREA 300 - Hydrochloric Acid Leach (4) AREA 400 – Sulfuric Acid (5) AREA 500 – Chlorination (6) AREA 600 – Rare Earth Elements Extraction (7) AREA 700 – Rare Earth Separation (8) AREA 800 – Chloride Recovery (9) AREA 900 – Sulfate Effluent Treatment Run of mine ore is stockpiled on surface and fed to a jaw crusher. The jaw crusher product is stored in a three-bin system and conveyed to the mineral processing plant. The mineral processing plant contains a High-Pressure Grinding Roll and cone crusher in closed circuit with screens to produce a uniform –1 mm product suitable for hydrometallurgical processing. Ore from the mineral processing unit is first activated in a rotary calciner to convert carbonate to oxides. Two of the main impurities, calcium and magnesium, are then sequentially leached and mineralized using an ammonium chloride cycle circuit. The ammonium chloride cycle leach residue, depleted in calcium and magnesium, is then subjected to a two-stage counter- current hydrochloric acid leach where iron, rare earths and scandium are solubilized. The resulting pregnant leach solution is contacted with a DGA-6 organic solution to selectively recover rare earths and scandium. The rare earth and scandium strip liquor is then sent to the REE separation unit where the rare earth elements and scandium are separated and recovered as individual oxide or mixed-carbonate products. The residue from the hydrochloric acid leach unit is dried before being subjected to a sulfuric acid bake where the niobium and titanium minerals are decomposed to soluble sulfate compounds. The residue from the acid bake process is leached with water and the non-soluble impurities are sent to paste backfill. The sulfate leach solution, rich in niobium and titanium, is hydrolyzed and the resulting hydrolysate, a combination of niobium and titanium compounds, is dewatered and calcined. The calcined hydrolysate is chlorinated, converting both niobium and titanium into their respective chlorides. The vapor is then sequentially condensed and distilled to yield a pure titanium
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 248 | Page tetrachloride product and a crude niobium chloride product. The crude niobium chloride product is then leached using water and re-hydrolyzed to generate a niobium oxide product which is subsequently converted into ferroniobium in the pyrometallurgical plant. The chloride effluent from REE extraction is concentrated and pyro-hydrolyzed to produce a mixed-oxide by-product, regenerating the hydrochloric acid used in the hydrochloric acid leach unit. The resulting hydrochloric acid produced by the pyro hydrolysis unit is condensed and recovered. All sulfate effluents are combined and neutralized using a combination of calcium carbonate and quicklime to precipitate all base metals as hydroxides and generate a treated water stream. The solid effluents from the process are recovered and sent to the paste backfill plant, where they are pumped underground as a structural paste backfill or pumped to the tailings impoundments for disposal 14.2 P ROCESS P LANT D ESIGN C RITERIA 14.2.1 Surface Crushing, Ore Storage & Mineral Processing The primary driver of the comminution circuit design is the dry processing of ore, which will be used to avoid an expensive drying operation prior to acid leaching. The process design relies upon two things; receiving a primary crusher product with a characteristic particle size of (P80) 115 mm at the comminution circuit feed bin and producing feed material for the downstream hydrometallurgical processing at a characteristic particle size of (P80) 1.1 mm. The primary crusher product will be fed to the secondary cone crusher system, operating in closed circuit with a double deck screen. The screen undersize from the cone crusher system will be fed to an HPGR unit, operating in closed circuit with another double deck screen. The HPGR screen undersize is the comminution product that will report to the hydrometallurgical process. The process design criteria are provided in Table 14‐1. Table 14‐1: Process Design Criteria Description Value Unit Throughput and Operational Time Non-operational Time 0 h/a Planned Down Time 252 h/a Unplanned Down Time 1,276 h/a Available Time 7,232 h/a Availability 85 % Annual Design Throughput 1,008,129t/a Process Plant Throughput 125 t/h Ore Characteristics Average Specific Gravity 2.96 - Moisture in Ore 5 % Bulk Density 1.8 t/m Angle of Repose 37 degrees Angle of Reclaim 60 degrees Test Work Parameters 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 249 | Page Description Value Unit JK Drop Weight Test A x b - Maximum 58.4 - A x b - Minimum 44.3 - SMC Test A x b - Maximum 56.4 - A x b - Minimum 34.9 - M, - Design 19.7 kWh/t Mih - Design 15.0 kWh/t Crushability and Grindability Tests Cwi 12.0 kWh/t Rw, - Design 17.9 kWh/t Bw, - Design 15.4 kWh/t A, - Design 0.112 g Crushing Circuit 139 t/hFeed Rate to Secondary Crusher Primary Crusher Product Size (Pao) 115 mm Primary Crusher Product Size (Ploo) 203 mm Crushed Ore Bin Reclaim Feeder Type Vibrating Feeder Design Feeder Capacity (Total) 160 t/h Number of Feeders 3 - Secondary Crusher Screen Screen Type Double Deck Vibratory Number of Screens 1 - Fresh Feed Throughput 139 t/h Secondary Crusher Recycle Throughput 171 t/h Total Screen Feed 311 t/h Number of Decks 2 - Top Deck Opening Size 50 mm Bottom Deck Opening Size 25 mm Product Sze (Pao) 22.4 mm Screen Size - Area 18 m Secondary Crusher Crusher Type Cone Average Throughput 171 t/h Number of Units 1 - Feed Size - Maximum (Firm) 203 mm Feed Size (Fao) 115 mm Close Side Setting 25 mm Product Size (Pao) 26 mm Selected Crusher Size HP300 or Equivalent- a 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 250 | Page Description Value Unit Crusher Motor Size 200 kW HPGR Circuit Crusher Type HPGR Feed Size (Fao) 22.4 mm Fresh Feed Throughput 139 t/h Total Throughput 198 t/h Number of Units 1 Specific Energy Consumption 4.18 kWh/t Selected Size POLYCOM 14/08 - 02 Installed Power 1,000 kW Product Size (Pao) 1.1 mm HPGR Screen Screen Type Double Deck Vibratory Number of Screens 1 - Screen Throughput 198 t/h Screen Recycle Throughput (to HPGR) 59 t/h Top Deck Opening Size 6 mm Bottom Deck Opening Size 3 mm Product Size (Pao) 1.10 mm Screen Size - Area 18 m Fine Ore Bin Fine Ore Bin - Storage Time 48.0 h Crushed Ore Bin - Live Capacity 6,000 t Fine Ore Bin Reclaim Feeder - Feeder Type Vibrating Feeder Design Feeder Capacity (Total) 144 t/h Number of Feeders 3 - Source: Magemi Mining Inc., 2026 14.2.2 Hydrometallurgical Plant The purpose of the Hydromet Plant is to extract the pay metals while separating them from the impurities. The process involves a series of successive unit- operations that include ore activation, leaching, purification, hydrolysis, chlorination, and solvent extraction. The hydrometallurgical process design criteria have been established based on bench, pilot, and demonstration scale test work conducted by L3 and KPM. The design criteria is also informed by similar projects and standard industry practices. The plant design criteria are provided in Table 14‐2. Table 14‐2: Plant Design Criteria Description Value Unit Throughput and Operational Time Available Time 7,920 h/a 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 251 | Page Description Value Unit Availability 90.4 % Design Throughput – Maximum 1,227,765st/yr Design Throughput - Average 1,109,900st/yr Process Plant Throughput 140.1 st/h 126.9 mt/h Ore Characteristics Average Specific Gravity 2.96 - Moisture in Ore 5 % Bulk Density 112.4 Lb/ft3 1.8 t/m Source: L3 Process Developments 2026 Note: The following nomenclature is used to identify the source of the process design criteria data. NCP = Calculated or established by NioCorp; L3 = Calculated or established by L3 Process Development; L3-T = Established by L3 Process Development using test work data; L3-H = Assumption made by L3 Process Development; OTH = Calculated or established by other party; LIT = Literature; SUP = Information from supplier; SGS = Calculated or established by SGS Lakefield; TBD = To be determined during the next engineering phase. Area 100 – Ore Activation The process design criteria for Area 100 – Ore Activation is presented as Table 14‐3. Table 14‐3: Area 100 – Ore Activation Process Design Criteria Equipment / Description DATA UNIT SOURCE 100 - ORE ACTIVATION UNIT 100 - CALCINATION CIRCUIT 100-RCA-001 - ORE ACTIVATION CALCINER Discharge Temperature 1,454 °F L3-T Residence Time 30 min L3-T 110-TEG-001 - CO2 DEHYDRATATION UNIT Moisture Content saturated % L3 Temperature 116 °F L3-H Source: L3 2026 Area 200 - Ammonium Chloride Cycle The process design criteria for Area 200 – Ammonium Chloride Cycle is presented as Table 14‐4. Table 14‐4: Area 200 – Ammonium Chloride Cycle Process Design Criteria Equipment / Description DATA UNIT SOURCE 200 - NH4Cl Leaching Unit 200 - 1st Stage Leaching Circuit 200-TAK-005-007 - NH4Cl LEACH STAGE 1 REACTOR #1 to #3 Temperature 210 °F L3-T Pressure Ambient - L3 Residence Time (each) 13.3 each min L3-T Percent Solid 10 % L3-T 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 252 | Page 200 – 2nd Stage Leaching Circuit 200-TAK-009-011 - NH4Cl LEACH STAGE 2 REACTOR #1 to #3 Temperature 210 °F L3-T Pressure Ambient - L3 Residence Time 13.3 min L3-T Percent Solid 10 % L3-T NH4Cl Solution Concentration 125 g/L L3-T 200 - Filtration Circuit 200-FPR-012/112 - NH4Cl LEACH STAGE 2 CANDLE FILTER #1 / #2 Residue Percent Solid 80 % L3-H Assumed filtration rate 5.25 ft3/h ft2 L3-H 210 - Filtration Circuit 210-FPR-001/101 - NH4Cl LEACH FILTER PRESS #1 / #2 Residue Percent Solid 80 % L3-H 220 - Crystallization Circuit 220-TAK-001 - 003 - Ca CARBONATATION REACTOR #1 to #3 Temperature 86 °F L3-T Pressure Ambient - L3 Residence Time 10 each min L3-T Percent Solid 3.6 % pH 8 L3-T CO2 30 VCFH L3-T 220-ROW-001 – REE EFFLUENT RO SYSTEM Temperature Ambient - L3 Water Recovery 80% Wt% L3 230 – NH4Cl Makeup Circuit 230-ROW-001 – NH4Cl RECOVERY RO SYSTEM Temperature Ambient - L3 Water Recovery 15% % L3 240 - Precipitation Circuit 240-TAK-002-004 - Mg CARBONATATION REACTOR #1 to #3 Temperature Ambient - L3 Pressure Ambient - L3 Residence Time 10 each min L3-T Residual Ammonium Carbonate Concentration 5 g/L L3 250 - MgCO3 Dewatering Circuit 250-BLF-001 - Mg CARBONATE RESIDUE BELT FILTER #1 Residue Percent Solid 80 % L3-H Cake Moisture TDS 0.1 wt% L3 260/270 – Reagent Recycle Circuit 200-TAK-002-004 - NH4Cl DEGASING TANK #1 to #3 Temperature 210 °F L3 Pressure atm psig L3 Residence Time 10 min L3 Source: L3 2026
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 253 | Page Area 300 - Hydrochloric Acid Leach The process design criteria for Area 300 - Hydrochloric Acid Leach is presented as Table 14‐5 Table 14‐5: Area 300 – Hydrochloric Acid Leach Process Design Criteria Equipment / Description DATA UNIT SOURCE 300 - HCl Leaching Unit 300 - 1st Stage Circuit 300-TAK-002/003 - 1ST STAGE HCl LEACH TANK Temperature 176 °F L3-T Pressure Ambient - L3-T Residence Time 10 each min L3-T Feed Percent Solid 27.5 % L3-T Disch. Percent Solid 13.8 % L3 300 - 2nd Stage Circuit 300-TAK-004/005 - 2nd STAGE HCl LEACH TANK Temperature 140 °F L3-T Pressure Ambient - L3-T Residence Time 10 each min L3-T Disch. Percent Solid 15.9 % L3 Residual Molarity 6.8 M [HCl] L3 310 - 1st Stage PLS Filtration 310-CAF-001/002/101 - 1ST STAGE HCl LEACH CANDLE FILTERS Cake Percent Solid 80 % L3-T Water Frac in Cake Moisture 99.99 wt% L3 Wash Efficiency 70 % L3-H Wash Stages 3 - L3 320 - Residue Dewatering Filtration Circuit 320-HYC-001 to 003 - 101/102 - DEWATERING STAGE 1 PRIMARY HYDROCYCLONE D95 to underflow 10 micron L3 Underflow Percent Solid 65 wt% L3-H 320-CAF-001/002-101 - HCl LEACH RESIDUE DEWATERING CANDLE FILTERS Cake Percent Solid 80 wt% L3-T Wash Efficiency 70 % L3-H 330 - HCl Leach Residue Drying Circuit 330-SCH-001 - HCl LEACH RESIDUE PRE-HEATER Discharge Temperature 212 °F L3 Discharge Percent Solids 95 wt% L3 Residence Time 20 Min L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 254 | Page 330-DRY-001 - HCl LEACH RESIDUE ROTARY DRYER Discharge Temperature 572 °F L3 Discharge Percent Solids 100 wt% L3 Residence Time 20 Min L3 Source: L3 2026 Area 400 – Sulfuric Acid The process design criteria for Area 400 – Sulfuric Acid is presented as Table 14‐6. Table 14‐6: Area 400 – Sulfuric Acid Process Design Criteria Equipment / Description DATA UNIT SOURCE 400 - Acid Baking Unit 400 - Acid Bake Circuit 400-PUG-001 - ACID BAKE PUG MILL Discharge Percent Solids 60 wt% L3 H2SO4 Flow Rate Ratio 0.625:1 L3-T 400-KLN-001 - ACID BAKE KILN Discharge Temperature 572 °F L3-T Residence Time min L3-T 400-SCR-001 - H2SO4 PRIMARY STAGE CONDENSING VENTURI Discharge Temperature 536 °F L3 400-SCR-001 - H2SO4 SECONDARY STAGE CONDENSING COLUMN Discharge Temperature 356 °F L3 410 - Water Leaching Unit 410 - Leaching Circuit 410-TAK-002-004 - WATER LEACH REACTOR #1 to #3 Temperature 176 amb to 176 maximum °F L3-T Pressure Ambient - L3 Residence Time 20 min L3-T Water Leach Solution Acidity (H2SO4) 0.3 M L3-T Percent Solid 30 % L3-T 410 - Filtration Circuit 410-CAF-001/002 - WTL PLS CANDLE FILTERS Cake Percent Solid 80 % L3 Number of Stages 3 L3 Wash Ratio (Barren: Solids) 3 : 1 L3 Wash Efficiency 70 % L3-H
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 255 | Page 420 - Dewatering Circuit 420-HYC-001 to 003 - 101/102 - DEWATERING STAGE 1 CYCLONE Solids Fraction to Underflow 98 wt% L3-H Underflow Percent Solid 70 wt% L3-H 420-HYC-004 to 006 - 104/105 - DEWATERING STAGE 2 CYCLONE Solids Fraction to Underflow 98 wt% L3-H Underflow Percent Solid 70 wt% L3-H 420-HYC-007 to 010 - 107/108 - DEWATERING STAGE 3 CYCLONE Solids Fraction to Underflow 98 wt% L3-H Underflow Percent Solid 70 wt% L3-H 420-CAF-001/002-101 - WATER LEACH RESIDUE DEWATERING CANDLE FILTERS Cake Percent Solid 80 % L3-H Number of Wash Stages 1 L3 Wash Ratio (Barren : Solids) 2 : 1 L3 Wash Efficiency 70 % L3-H 430 - Hydrolysis Unit 430 - 1st Stage Circuit 430-TAK-001 - STG 1 HYDROLYSIS REACTOR Temperature 212 °F L3-T Pressure Ambient - L3-T Residence Time 20 min L3-T 430 - 2nd Stage Circuit 430-TAK-002 - STG 2 HYDROLYSIS REACTOR Temperature 212 °F L3-T Pressure Ambient - L3-T Residence Time 20 min L3-T 440 - Barren Filtration Circuit 440-CAF-001/003-101 - BARREN FILTRATION CANDLE FILTER Cake Percent Solid 80 % L3-H Number of Wash Stages 1 L3 Wash Ratio (Solution: Solids) 3 : 1 L3 Wash Efficiency 70 % L3-H 450 - Residue Drying Circuit 450-RCA-001 - HYDROLYSIS CAKE CALCINER Discharge Temperature 1562 °F L3-T
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 256 | Page S Residual Concentration 0.27 wt% L3-T Source: L3 2026 Area 500 – Chlorination The process design criteria for Area 500 – Chlorination is presented as Table 14‐7. Table 14‐7: Area 500 – Chlorination Process Design Criteria Equipment / Description DATA UNIT SOURCE 500 - Chlorination Circuit 500-CLN-001/101 - CHLORINATOR Temperature 1742 °F L3 Petroleum Coke:Feed Ratio 0.27 : 1 L3 Discharge Chlorine Concentration 0.25 Mole % L3 Discharge Nitrogen Concentration 35 Mole % L3 500 - CLN Condensation Circuit 500-SCR-001 - Nb/Fe CONDENSER Temperature 267 °F L3 Solids Fraction in Bottoms 30 Wt% L3 500-HTX-001 - Nb/Fe CONDENSER COOLER Type Shell & Tube L3 Temperature (In/Out) Process Side 267 / 248 °F L3 Utility Side 140 / 248 °F L3 Heat Transfer Fluid Thermal Fluid L3 510-SCR-002 - TiCl4 PRIMARY CONDENSER Temperature 86 °F L3 500-HTX-002 - TiCl4 PRIMARY CONDENSER COOLER Type Shell & Tube L3 Temperature (In/Out) Process Side 86 / 81 °F L3 Utility Side 68 / 86 °F L3 Heat Transfer Fluid Cooling Water L3 500-SCR-003 - TiCl4 SECONDARY CONDENSER Temperature 19.4 °F L3 500-HTX-003 - TiCl4 SECONDARY CONDENSER COOLER Type Shell & Tube L3 Temperature (In/Out) Process Side 19 / 0 °F L3 Utility Side -20 / 0 °F L3 Heat Transfer Fluid Ammonia L3 510 - TiCl4 Treatment Unit 510 - TiCl4 Degas Circuit
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 257 | Page 510-TAK-002 - TiCl4 DEGAS TANK Temperature 277 °F L3 Pressure TBD In HG TBD Residence Time 60 min L3 510-HTX-002 – CRUDE TiCl4 FEED HEATER Type Tube Bundle Temperature (In/Out) Process Side 277 / 277 °F L3 Utility Side 482 / 302 °F L3 Heat Transfer Fluid Thermal Fluid L3 510-CND-001 - TiCl4 DEGAS TANK CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 86 °F L3 510 - TiCl4 Vaporization Circuit 510-TAK-004 - TiCl4 VAPORIZOR #1 Temperature 277 °F L3 Experience Pressure TBD In HG TBD Residence Time 60 min L3 Solids Content 33.3 Wt% L3 510-HTX-004 – TiCl4 VAPORIZOR #1HEATER Type Tube Bundle Temperature (In/Out) Process Side 277 / 277 °F L3 Utility Side 482 / 302 °F L3 Heat Transfer Fluid Thermal Fluid L3 510-CND-002 - TiCl4 VAPORIZOR #1 CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 201 °F L3 510-TAK-006 - TiCl4 VAPORIZOR #2 Temperature 277 °F L3 Experience Pressure TBD In HG TBD Residence Time 60 min L3 TiCl4 Vaporization Extent 92 % L3 510-HTX-006 – TiCl4 VAPORIZOR #2 HEATER Type Tube Bundle Temperature (In/Out) Process Side 277 / 277 °F L3 Utility Side 482 / 302 °F L3 Heat Transfer Fluid Thermal Fluid L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 258 | Page 510-CND-003 - TiCl4 VAPORIZOR #2 CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 201 °F L3 520 - TiCl4 Purification Unit 520 - TiCl4 Stripping Circuit 520-SCR-001 - TiCl4 STRIPPER Type Packed Column L3 Reboiling Ratio (Vapor / Feed) 2.51 L3 Reflux Ratio (Reflux / Feed) 1.61 L3 520-HTX-001 – TiCl4 STRIPPER REBOILER Type Shell & Tube Thermosiphon L3 Temperature (In/Out) Process Side 277 / 284 °F L3 Utility Side 482 / 302 °F L3 Heat Transfer Fluid Thermal Fluid L3 510-CND-003 - TiCl4 STRIPPER O/H CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 86 °F L3 520 - TiCl4 Purification Circuit 520-COL-001 - TiCl4 PURIFICATION COLUMN Type Mixed, Packing and Trays L3 Reboiling Ratio (Vapor / Feed) 1.50 L3 Reflux Ratio (Reflux / Feed) 0.39 L3 520-TAK-004 - TiCl4 PURIFICATION COLUMN REBOILER TANK Temperature 284 °F L3 Pressure TBD In HG TBD Residence Time 120 min L3 Mineral Oil Addition Rate (Mineral Oil / Feed) 0.0014 L3 Bleed Rate (Bleed / Feed) 0.034 L3 520-HTX-004 – TiCl4 PURIFICATION COLUMN REBOILER HEATER Type Tube Bundle Temperature (In/Out) Process Side 277 / 284 °F L3 Utility Side 392 / 374 °F L3 Heat Transfer Fluid Thermal Fluid L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 259 | Page 510-CND-003 - TiCl4 PRODUCT O/H CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 104 °F L3 530 - Nb Recovery Unit 530 - Nb Recovery Circuit 530-SCH-001 - Nb/Fe CHLORIDE DRYER Type Screw Dryer L3 Temperature (In/Out) Process Side 267 / 464 °F L3 Utility Side 482 / 392 °F L3 Heat Transfer Fluid Thermal Fluid L3 Solids Discharge % 100 Wt% L3 530-SCR-001 - TiCl4 RECOVERY CONDENSER Temperature 277 °F L3 530-HTX-001 - TiCl4 RECOVERY CONDENSER COOLER Type Finned HTX L3 Temperature (In/Out) Process Side 277 / 86 °F L3 540 - TiCl4 Vapor Recovery Unit 540 - TiCl4 Vapor Recovery Circuit 540-SCR-001 - TiCl4 VENT CONDENSER Discharge Temperature 81 °F L3 530-HTX-001 - TiCl4 RECOVERY CONDENSER COOLER Type Finned HTX L3 Temperature (In/Out) Process Side 81 / 77 °F L3 540-SCR-002 - TiCl4 VENT SCRUBBER TiCl4 Scrubbing Efficiency 100 % L3 Cl2 Scrubbing Efficiency > 99 % L3 550 - Chlorination OFF-GAS Management Unit 550 - CO Boiler & FGD Scrubber Circuit 550-TOX-001 - THERMAL OXIDIZER Discharge Temperature 1,600 °F L3 Heat Recovery Temperature (In/Out) Process Side 1,600 / 284 °F L3 Utility Side 68 / 482 °F L3 Heat Transfer Fluid Thermal Fluid L3 550-SCR-001 - FGD SCRUBBER VENDOR PACKAGE SO2/SO3 Scrubbing Efficiency > 97 % L3 560 - Nb Recovery Unit
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 260 | Page 540 - Nb Hydrolysis Circuit 560-TAK-001/002/003 - Nb/Fe STAGE #1/#2/#3 HYDROLYSIS TANK Temperature 212 °F L3 Pressure Ambient - L3 Residence Time 30 min L3 Steam Injection Ratio 0.55 L3 Dilution Ratio 3 L3 560-CND-001/002/003 - Nb/Fe STAGE #1/#2/#3 HYDROLYSIS CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 212 / 176 °F L3 560 - Nb Dewatering Circuit 560-CA-001/002 - Nb/Fe HYDROLYSIS CANDLE FILTER Cake Percent Solid 70 % L3-H Number of Wash Stages 1 L3 Wash Ratio (Solution: Solids) 3 : 1 L3 Wash Efficiency 70 % L3-H 560 - Nb Product Calcination Circuit 560-RCA-001 - Nb CALCINER Discharge Temperature 1,112 °F L3 Source: L3 2026 Area 600 – Solvent Extraction The process design criteria for Area 600 – Solvent Extraction is presented as Table 14‐8. Table 14‐8: Area 600 – Solvent Extraction Process Design Criteria Equipment / Description DATA UNIT SOURCE 600 - REE Extraction 600 - REE Extraction 600-COL-001 - DGA-6 EXTRACTION COLUMN Temperature AMB °C L3-T Capacity Factor 40 m3/(m2*h) SUP Efficiency / Stage per Meter 4 SUP 600-COL-002 - DGA-6 SCRUB COLUMN Temperature AMB °C L3-T Capacity Factor 40 m3/(m2*h) SUP Efficiency / Stage per Meter 4 SUP 610 - Acid Scrub 610 - Acid Scrub 610-MSE-001|101 - DGA-6 ACID SCRUB MIXER-SETTLER
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 261 | Page Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 1:3 L3-T Internal O:A Ratio 0.9:1 L3 Scrub Solution pH 1.5 L3 610 - Acid Scrub Neutralization 610-TAK-006-008 - DGA-6 ACID SCRUB. NEUT. REACTOR #1 TO #3 Temperature Amb °C L3 Pressure atm psig L3 Residence Time 60 min L3-H 610 - Acid Scrub Filtration 610-CAF-001-003 - DGA-6 ACID SCRUB NEUT. RESIDUE FILTER #1 TO #3 Cake Percent Solid 70 % L3-H Number of Wash Stages 2 L3 Wash Efficiency 80 % L3-H Filtrate Mg Concentration 51 g/L L3 620 – REE Strip 620 – REE Strip 600-MSE-002-005 - DGA-6 STR 1 TO 4 MIXER-SETTLER Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 2:1 L3 Internal O:A Ratio 1.1:1 L3 630 - Iron Removal 630 - Neutralization circuit 630-TAK-001-003 - DGA-6 STRIP LIQ. NEUT. REACTOR #1 TO #3 Temperature Amb °C L3 Pressure atm psig L3 Residence Time 60 min L3 630 - DGA-6 Strip Filtration 630-CAF-001-003 - DGA-6 STRIP LIQ. NEUT. RESIDUE FILTER #1 TO #3 Cake Percent Solid 80 % L3-H Number of Wash Stages 1 L3 Wash Efficiency 80 % L3-H Cake Moisture TDS 0.01 Wt% L3 Source: L3 2026 Area 700 – Rare Earth Separation The process design criteria for Area 700 – Rare Earth Separation is presented as Table 14‐9. Note: The following nomenclature is used to identify the solvent extraction process stage. SAP = Saponification, EXT = Extraction, SCB = Scrubbing, STR = Stripping and SCV = Scavenging. Table 14‐9: Area 700 – Rare Earth Separation Equipment / Description DATA UNIT SOURCE
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 262 | Page 700 - Primary Circuit 700 - Primary Circuit 700-MSE-001|01-02 – PRIMARY CIRCUIT: SAP Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 2 L3 Internal O:A Ratio 1.1 L3 Extractant – Cyanex 572 35 V% L3 Diluent – D80 Kerosene 65 V% L3 Saponification Solution NH4OH, NH4Cl L3 700-MSE-002|01-06 - PRIMARY CIRCUIT: EXT Number of Stages 6 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 0.048 L3 Internal O:A Ratio 1.1 L3 Raffinate pH 2.1 L3 700-MSE-003|01-16 - PRIMARY CIRCUIT: SCB Number of Stages 16 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 2.56 L3 Internal O:A Ratio 1.1 L3 Scrub Solution HCl Concentration 0.70 Mol/L L3 700-MSE-004|01-24 - PRIMARY CIRCUIT: STR1 Number of Stages 24 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 3.8 L3 Internal O:A Ratio 1.1 L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 263 | Page Strip Solution HCl Concentration 1.10 Mol/L L3 700-MSE-005|01-06 - PRIMARY CIRCUIT: STR2 Number of Stages 6 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 6.53 L3 Internal O:A Ratio 1.1 L3 Strip Solution HCl Concentration 1.80 Mol/L L3 710 - NdPr Circuit 710 - NdPr Circuit 710-MSE-001|01-02 - NdPr CIRCUIT: SAP Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 2 L3 Internal O:A Ratio 1.1 L3 Extractant – Cyanex 801 35 V% L3 Diluent – D80 Kerosene 65 V% L3 Saponification Solution NH4OH, NH4Cl L3 710-MSE-002|01-12 - NdPr CIRCUIT: EXT Number of Stages 12 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 0.066 L3 Internal O:A Ratio 1.1 L3 Raffinate pH 1.8 L3 710-MSE-003|01-24 - NdPr CIRCUIT: SCB Number of Stages 24 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 1.99 L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 264 | Page Internal O:A Ratio 1.1 L3 Scrub Solution HCl Concentration 0.80 Mol/L L3 710-MSE-004|01-06 - NdPr CIRCUIT: STR Number of Stages 6 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 4.67 L3 Internal O:A Ratio 1.1 L3 Strip Solution HCl Concentration 1.25 Mol/L L3 720 - Tb Circuit 720 - Tb Circuit 720-MSE-001|01-02 - Tb CIRCUIT: SAP1 Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 0.5 L3 Internal O:A Ratio 1.1 L3 Extractant – Cyanex 572 35 V% L3 Diluent – D80 Kerosene 65 V% L3 Saponification Solution NH4OH, NH4Cl L3 720-MSE-002|01-16 - Tb CIRCUIT: EXT Number of Stages 16 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 0.84 L3 Internal O:A Ratio 1.1 L3 Raffinate pH 1.25 L3 720-MSE-003|01-12 - Tb CIRCUIT: SCB Number of Stages 12 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 265 | Page Overall O:A Ratio 2.5 L3 Internal O:A Ratio 1.1 L3 Scrub Solution HCl Concentration 1.1 Mol/L L3 720-MSE-004|01-02 - Tb CIRCUIT: SAP2 Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 0.5 L3 Internal O:A Ratio 1.1 L3 Saponification Solution NH4OH, NH4Cl L3 720-MSE-005|01-32 - Tb CIRCUIT: SCV Number of Stages 32 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 1.73 L3 Internal O:A Ratio 1.1 L3 Feed Solution pH 0.93 L3 Raffinate pH 1.2 L3 720-MSE-006|01-24 - Tb CIRCUIT: STR Number of Stages 24 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 6.02 L3 Internal O:A Ratio 1.1 L3 Strip Solution HCl Concentration 1.30 Mol/L L3 730 - Dy Circuit 730 - Dy Circuit 730-MSE-001|01-02 - Dy CIRCUIT: SAP Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 266 | Page Overall O:A Ratio 0.5 L3 Internal O:A Ratio 1.1 L3 Extractant – Cyanex 572 35 V% L3 Diluent – D80 Kerosene 65 V% L3 Saponification Solution NH4OH, NH4Cl L3 730-MSE-002|01-12 - Dy CIRCUIT: EXT Number of Stages 2 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 2.06 L3 Internal O:A Ratio 1.1 L3 Feed Solution pH 1.0 Raffinate pH 1.25 L3 730-MSE-003|01-24 - Dy CIRCUIT: SCB Number of Stages 24 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 4.92 L3 Internal O:A Ratio 1.1 L3 Scrub Solution HCl Concentration 1.45 Mol/L L3 730-MSE-004|01-06 - Dy CIRCUIT: STR Number of Stages 6 L3 Mixer Residence Time 5 min L3 Settler Residence Time 12.5 min L3 Overall O:A Ratio 13.1 L3 Internal O:A Ratio 1.1 L3 Strip Solution HCl Concentration 2.5 Mol/L L3 740 - SEG Recovery Unit 740 - SEG Carbonate Precipitation Circuit 740-TAK-002-004 - SEG CARBONATE PRECIP. TANK #1 to #3 Temperature amb °C L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 267 | Page Pressure atm psig L3 Residence Time 60 min L3 740-CLR-001 - SEG CARBONATE CLARIFIER Discharge Solids Fraction 50.0 % L3 740 - SEG Carbonate Dewatering Circuit 740-CAF-001/101 - SEG CARBONATE CANDLE FILTER #1/#2 Cake Percent Solid 65 % L3-H Number of Wash Stages 2 L3 Cake Moisture TDS 0.01 Wt% L3 Wash Efficiency 80 % L3-H 740 - SEG Carbonate Drying Circuit 740-RD-001 - SEG CARBONATE ROTARY DRYER Discharge Temperature 248 °F L3 Residence Time 15 Min L3-H 750 - HREY Recovery Unit 750 - HREY Carbonate Precipitation 750-TAK-002-004 - HREY CARBONATE PRECIP. TANK #1 to #3 Temperature amb °F L3 Pressure atm psig L3 Residence Time 60 min L3 750-CLR-001 - HREY CARBONATE CLARIFIER Discharge Solids Fraction 50.0 % L3 750 - HREY Carbonate Dewatering 750-CAF-001/101 - HREY CARBONATE CANDLE FILTER #1/#2 Cake Percent Solid 65 % L3-H Number of Wash Stages 2 L3 Cake Moisture TDS 0.01 Wt% L3 Wash Efficiency 80 % L3-H 750 - HREY Carbonate Drying Circuit 750-RD-001 - HREY CARBONATE ROTARY DRYER Discharge Temperature 248 °F L3 Residence Time 15 Min L3-H 760 - NdPr Recovery Unit
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 268 | Page 760 - NdPr Oxalate Precipitation Circuit 760-TAK-002-004 - NdPr OXALATE PRECIP. TANK #1 to #3 Temperature Amb °F L3 Pressure atm psig L3 Residence Time 60 min L3 Residual Oxalic Acid Concentration 5 g/L L3 760 - NdPr OXALATE Dewatering Circuit 760-CAF-001/101 - NdPr OXALATE CANDLE FILTER #1/#2 Cake Percent Solid 65 % L3-H Number of Wash Stages 2 L3 Cake Moisture TDS 0.01 Wt% L3 Wash Efficiency 80 % L3-H 760 - NdPr OXALATE Calcining Circuit 760-RCA-001 - NdPr OXALATE ROTARY CALCINER Discharge Temperature 1,562 °F L3 Residence Time 30 Min L3-H 770 - Tb Recovery Unit 770 - Tb Oxalate Precipitation Circuit 770-TAK-002-004 - Tb OXALATE PRECIP. TANK #1 to #3 Temperature Amb °F L3 Pressure atm psig L3 Residence Time 60 min L3 Residual Oxalic Acid Concentration 5 g/L L3 770 - Tb OXALATE Dewatering Circuit 770-CAF-001/101 - Tb OXALATE CANDLE FILTER #1/#2 Cake Percent Solid 65 % L3-H Number of Wash Stages 2 L3 Cake Moisture TDS 0.01 Wt% L3 Wash Efficiency 80 % L3-H 770 - Tb OXALATE Calcining Circuit 770-RCA-001 - Tb OXALATE ROTARY CALCINER Discharge Temperature 1,562 °F L3 Residence Time 30 Min L3-H 780 - Dy Recovery Unit 780 - Dy Oxalate Precipitation Circuit
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 269 | Page 780-TAK-002-004 - Dy OXALATE PRECIP. TANK #1 to #3 Temperature Amb °F L3 Pressure atm psig L3 Residence Time 60 min L3 Residual Oxalic Acid Concentration 5 g/L L3 780 - Dy OXALATE Dewatering Circuit 780-CAF-001/101 - Dy OXALATE CANDLE FILTER #1/#2 Cake Percent Solid 65 % L3-H Number of Wash Stages 2 L3 Cake Moisture TDS 0.01 Wt% L3 Wash Efficiency 80 % L3-H 780 - Dy OXALATE Calcining Circuit 780-RCA-001 - Dy OXALATE ROTARY CALCINER Discharge Temperature 1,562 °F L3 Residence Time 30 Min L3-H 790 - Sc Recovery Unit 790 - Scandium Prestripitation Circuit 790-TAK-002/003 - Sc PRESTRIPITATION TANK #1/#2 Temperature 122 °F SGS Pressure atm psig L3 Residence Time 30 min L3-H [NaOH] 100 g/L L3 [NaCl] 1 Mol/L L3 Tank #2 O:A 2:1 L3 Tank #2 O:A 1:1 L3 790-CAF-001/101 - Sc BARREN ORG. CANDLE FILTER Cake Percent Solid 80 % L3-H Cake Flush Water Ratio 4 L3 790-THK-001 - Sc PRESTRIPITATION 3-PHASE SEPARATOR Residence Time 24 min L3-H Underflow Phases Aqueous / Solids L3 790-CAF-002/003 - Sc(OH)3 CANDLE FILTER #1/#2 Cake Percent Solid 75 % L3-H
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 270 | Page Number of Wash Stages 1 L3 Wash Ratio (Solution : Solids) 3 : 1 L3 Wash Efficiency 70 % L3-H 795 - Scandium Purification 795 - Scandium Hydroxide Leach Circuit 795-TAK-001 - Sc(OH)3 LEACH TANK Temperature Amb °F L3 Pressure atm psig L3 Residence Time 60 min L3-H Residual H2SO4 0.01 M L3-H 795 - Scandium Purification Circuit 795-TAK-003 - ScP EXT TANK Temperature Amb °F SGS Pressure atm psig SGS Residence Time 60 min L3-H O:A Ratio 1 SGS Extractant – Alamine 336 2.5 V% SGS Extractant – Aliquat 336 2.5 V% SGS Modifier - Tridecanol 2.5 V% SGS Diluent – D80 Kerosene 92.5 V% SGS 795-TAK-004 - ScP LOADED ORG. TANK Temperature Amb °F NCP Pressure atm psig L3 Residence Time 60 min L3-H O:A Ratio 1 NCP [H2SO4] 50 g/L NCP 795-TAK-005 - ScP COND TANK Temperature Amb °F NCP Pressure atm psig L3 Residence Time 60 min L3-H [NaOH] 50 Wt% NCP 795 - Scandium Oxalate Precipitation 795-TAK-006 - Sc OXALATE PRECIPITATION TANK
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 271 | Page Temperature Amb °F NCP Pressure atm psig L3 Residence Time 60 min L3 Oxalic Acid Stochiometric Excess Ratio 1.25 L3 795-BLF-001 - Sc OXALATE VACUUM BELT FILTER Cake Solids Fraction 70 % L3 Wash Water to Solid Ratio 5 m3/dmt L3 Number of Wash Stages 3 L3 Wash Efficiency 98 % L3 795 - Scandium Oxalate Calcination 795-RCA-001 - SCANDIUM OXIDE ROTARY CALCINER Discharge Temperature 1,832 °F L3-H Residence Time 30 Min L3-H Source: L3 2026 Area 800 – Chloride Recovery The process design criteria for Area 800 – Chloride Recovery is presented as Table 14‐10. Table 14‐10: Area 800 – Chloride Recovery Process Design Criteria Equipment / Description DATA UNIT SOURCE 820 – HCl Recovery 820 – HCl Absorption 820-COL-001/011 - HCl QUENCH TOWER Type Packed-Bed Column L3 Temperature 122 °F 820-HTX-001/011 – HCl QUENCH COOLER Type Shell & Tube L3 Temperature (In/Out) Process Side 122 / 41 °F L3 Utility Side -20 / -10 °F L3 Heat Transfer Fluid Ammonia L3 820-COL-002/012 - HCl CONDENSER Type Packed-Bed Column L3 Temperature 86 °F 820-HTX-002/012 – HCl CONDENSER COOLER Type Shell & Tube L3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 272 | Page Temperature (In/Out) Process Side 86 / 41 °F L3 Utility Side -20 / -10 °F L3 Heat Transfer Fluid Ammonia L3 840 - MgCl2 Pyrohydrolysis Unit 840 - MgCl2 Pre-Evaporation Circuit 840-EVP-001 – CHLORIDE PRE-EVAPORATOR Type Vertical tubes L3 Temperature 263 °F L3 Chloride Concentration in Concentrate 430 g/L L3 Temperature (In/Out) Utility Side 482/ 248 °F L3 Heat Transfer Fluid Heat Transfer Fluid L3 840-CND-001 – Chloride PRE-EVAP CONDENSER Type Finned HTX L3 Temperature (In/Out) Process Side 262 / 176 °F L3 850 - MgCl2 Spray Roasting Circuit 850-SPR-001 - CHLORIDE PYROHYDROLYSIS SPRAY ROASTER Temperature 1,472 °F L3 Gas Velocity 1.65 ft/s L3 Gas residence time 30 sec L3 Source: L3 2026 Area 900 – Sulfate Effluent Treatment The process design criteria for Area 900 – Sulfate Effluent Treatment is presented as Table 14‐11. Table 14‐11: Area 900 – Sulfate Effluent Treatment Process Design Criteria Equipment / Description DATA UNIT SOURCE 950 – Sulfate Effluent Treatment 950 – Sulfate Effluent Neutralization 950-TAK-002/003/004 – SULFATE EFFLUENT NEUTRALIZATION TANK Temperature Amb °F L3 Pressure atm psig L3 Residence Time 20 min L3 Neutralization Reagent CaCO3 L3 Discharge pH 4.5 L3 950-TAK-021/022/023 – SULFATE EFFLUENT NEUTRALIZATION TANK
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 273 | Page Temperature Amb °F L3 Pressure atm psig L3 Residence Time 20 min L3 Neutralization Reagent Ca0 L3 Discharge pH 8 L3 950-BLF-030/031/040/041 – SULFATE EFFLUENT BELT FILTER Cake Solids Fraction 65 % L3 Source: L3 2026 14.2.3 Pyrometallurgical Plant As stated in a previous report, niobium improves the mechanical properties of the high-grade steel and producing a ferro- niobium alloy was an attractive way for NioCorp to supply potential future steelworks factories customers. The pyrometallurgical process design criteria were established based on thermodynamic calculations, inspired by test results completed by and supported by the literature available on the aluminothermic reduction as well as on the niobium pyrometallurgy. Table 14‐12 presents the pyromet design criteria. Table 14‐12: Pyrometallurgical process design criteria. Section Description Value Units NaNbO Precipitate Pelletized NaNbO Precipitate Feed Rate (Dry Basis) 1.16 t/h 27.9 t/d Moisture Content (After Pelletizing) <1 % Storage capacity 14 days Bulk density 4.3 Tm/m Sodium Niobium trioxide Precipitate Composition Na 15.6 %w/w Nb 55.0 %w/w Nb Precipitate Pellets Number of bins 1 ea. Storage time 11 days Capacity 324 t Aluminum (Al) pellets Aluminum (Al) feed rate 3.9 t/batch Number of bins 1 ea. Storage time 13 days Capacity 162 t 3 3 3
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 274 | Page Section Description Value Units Hematite (FeO) Pellets Hematite (FeO) feed rate 2.4 t/batch Number of bins 1 ea. Storage time 13 days Capacity 150 t Calcium fluoride (CaF) Feed rate 0.15 t/batch Super sacks rack (1 Tm or 2Tm) 1 ea. Limestone (CaCO) Limestone feed rate 0.87 t/batch Super sacks rack (1 Tm or 2Tm) 1 ea. FeNb Furnace – Aluminothermic Reduction Total Feed to FeNb Furnace 11.2 t/batch Operating Temperature 1700 to 1750 °C FeNb Furnace Power Electric Induction Furnace 420 kW Power Consumption Per Ton Precipitate Pellets 182 kW/t Furnace Thermal Efficiency 60.0 % Furnace Design Power 1000 kW Nb Recovery 96.6 % Furnace Cooling system Water Flow Rate 36 m³/h Cooling Tower 1 ea. FeNb Furnace - FeNb Alloy Composition Nb 64.9 %w/w Fe 34.0 %w/w Al 0.9 %w/w FeNb Alloy Tapping FeNb Alloy per batch 4.7 t/batch Tapping Schedule 2 taps/8-hour shift 4 taps/day Tapping Time 10.0 min/tap Mass per tap 5.6 t/tap Daily production 22.4 t/d density 8.2 t/m3 Slag production Slag per batch 9.9 t/batch NbO 1.0 %w/w 2 3 2 3 2 3 2 5
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 275 | Page Section Description Value Units Furnace Slag Composition FeO 1.9 %w/w FeNb (trapped) 0.3 %w/w AlO 92.1 %w/w CaO 3.2 %w/w CaF 1.5 %w/w Slag density 4.0 t/m³ Slag tapping Slag per tap 9.9 t/batch Tapping Schedule 4 8 taps/day Tapping Time 15.0 min/tap Daily slag production 39.6 t/day FeNb Furnace Off gas HandlingDust: largely recycled ___ % Gas generation 0.07 t/day FeNb Pelletizing system Cooling water 15.1 m³/h Source: MCS 2026 Notes: (1) This Process Design Criteria applies for Hydromet feed and 2025 campaign test. (2) The mass distribution presented reflects the conversion of oxide feed materials into metallic alloy and slag phases during aluminothermic reduction. The apparent increase in condensed-phase mass relative to the initial solid feed is primarily attributed to oxygen transfer from metal oxides to aluminum, resulting in the formation of Al₂O₃-rich slag, as well as the contribution of fluxing agents. Gas generation, including CO₂ from limestone decomposition and sodium-bearing vapors, is not included in the condensed-phase mass balance and accounts for the observed difference between total feed and product streams 14.3 F LOWSHEETS AND P ROCESS D ESCRIPTION 14.3.1 Surface Crushing, Ore Storage & Mineral Processing Plant The ROM ore from the underground mine will be transported to a surface ROM stockpile, located in front of the primary crushing circuit. The ore will be fed via grizzly feeder and screen to a C135 primary jaw crusher, and the crushed product with a top size of 203 mm and characteristic size (Pao) of 115 mm, will be delivered by the means of a three-way diverter splitter to three crushed ore bins each with a capacity of 1,400mt. This part of the crushing circuit will operate on a 10 hours per day schedule with the subsequent crushing and the processing plant will operate 24 hour per day. The ore from the primary crushing circuit will be reclaimed from the ore bins by three feeders with a total capacity of 139 t/h and passed on to the secondary crusher circuit via the secondary crusher screen feed conveyor. 2 3 2 3 2
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 276 | Page At the secondary crushing stage, the ore will be sized on a dry, double deck screen with a top deck aperture size of 50 mm and bottom deck aperture size of 25 mm. The screen oversize from both decks will report to the secondary crushing stage consisting of a single cone crusher unit. The screen undersize will be conveyed to a High-Pressure Grinding Rolls (HPGR) circuit. The screen oversize fractions will be crushed in a single secondary cone crusher operating with a closed side setting of 25 mm. The secondary crushed product will be sized by the same double deck screen with the primary crusher discharge ore. The screen undersize, at an approximate characteristic particle size (Pao) of 22 mm, will be further crushed in the HPGR circuit. The HPGR circuit will consist of a single HPGR unit, with a separate double-deck vibrating screen with top and bottom deck aperture sizes of 6 mm and 3 mm, respectively. The recirculating load of the HPGR circuit is expected to be in the range of 30 to 40% of the circuit new feed. The HPGR screen undersize will be the final comminution product and is expected to have a characteristic particle size (Pao) of 1.1 mm. The ore will be stored in a fine ore bin, then reclaimed by a vibrating feeder with a design capacity of 132 t/h, and then passed on to the acid leach circuit via the acid leach feed conveyor for further processing. The overall primary, secondary, and HPGR crushing conceptual block flow diagram is presented in Figure 14‐1. Source: Magemi Mining Inc., 2026 Figure 14‐1:Overall Crushing Conceptual Block Flow Diagram 14.3.2 Hydrometallurgical Plant The majority of the unit processes selected for the hydrometallurgical flowsheet have been extensively reported in literature and are predominately proven and existing processes. The plant consists of multiple buildings that will house separate physical and chemical processes required to separate the niobium, scandium, titanium and rare earth elements that are contained in the ore and to regenerate and recover reagents for reuse.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 277 | Page Area 100 – Ore Activation The ore activation area is used to convert the carbonate minerals in the feed material to oxides through thermal decomposition while recovering the CO2 generated in the process. A simplified block flow diagram is presented as Figure 14‐2. Source: L3 2026 Figure 14‐2:Area 100 – Ore Activation Block Flow Diagram Unit 100 – Ore Activation The ore activation circuit converts the carbonates in the feed material to oxides through thermal decomposition. Activation of the feed ore is accomplished by heating the feed material to approximately 1454°F (790°C) in the indirect natural gas rotary calciner. The high heat converts the carbonate feed material into their oxide components. The conversion releases CO2 gas that is captured, treated, and reused. Following the calcination process, the calcined ore is cooled in the activated material cooler and conveyed to Area 200 – Ammonium Chloride Cycle by the Activated Material Conveyor. Waste heat from the calciner natural gas combustion is recovered using the activation Calciner Waste heat exchanger. The energy is recovered using thermal fluid. The CO2 released during the calcination process is captured and filtered using an electro-filter. The filtered gas is then cooled, and physical liquid is separated from the gas in the CO2 Knockout Drum. Once the remaining moisture has been removed from the CO2 gas, the CO2 is transferred and stored via a blower. It is stored in the CO2 distribution tank. Area 200 – Ammonium Chloride Cycle The ammonium chloride cycle area is used to selectively leach calcium and magnesium from the calcined ore feed material using a closed loop circuit. The calcium and magnesium are then sequentially recovered through carbonate mineralization, regenerating the ammonium chloride leach reactant, which is recycled to the leach circuit. A simplified block flow diagram is presented as Figure 14‐3.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 278 | Page Source: L3 2026 Notes: The following abbreviations are used in the block flow diagram: NHL = Ammonium Chloride Leach; CaP = Calcium Precipitation; MgP = Magnesium Precipitation; BCO = Scrubbing Unit. Figure 14‐3:Area 200 – Ammonium Chloride Cycle Block Flow Diagram Unit 200 – NH4Cl Leach The ammonium chloride leach circuit is used to selectively leach calcium and magnesium from the calcined ore feed material. This leach reaction converts ammonium chloride into ammonium hydroxide which is partially vaporized and recovered. The calcined material from Unit 100 – Ore Activation is stored in a day bin, prior to being fed into the NH4Cl Leach reactors where is it mixed with the stage 2 leach ammonium chloride solution and the resulting slurry is pumped to the stage 1 NH4Cl Leach Circuit. The stage 1 NH4Cl Leach Circuit is composed of a cascade of three agitated tanks in series, each with external heating loops to maintain the reactors at their operating temperature. The discharge of the third reactor is hydrocycloned and the overflow is filtered using candle filters. The filtrate is sent to Unit 220 – Calcium Carbonatation while the solids are sent to the stage 2 NH4Cl Leach Circuit. In stage 2, the residue from stage 1 is mixed with fresh hot NH4Cl solution from Unit 260 – Degassing and processed in a cascade of three agitated tanks in series, each with external heating loops to maintain the reactors at their operating temperature. The discharge of the third reactor is sent to Unit 210 – NH4Cl Filtration. Vapor leaving the reactors are condensed in the ammonium carbonate scrubber located in Unit 260/270 – Ammonium Carbonate and Scrubber Units. Unit 210 – NH4Cl Filtration
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 279 | Page The NH4Cl Filtration circuit comprises three identical filtration trains which the NH4Cl Leach slurry from Unit 200 – NH4Cl Leach is split between. The slurry is filtered using plate and frame presses to separate the Ca/Mg-rich pregnant leach solution from the remaining oxide solids in the system. The filtrate from the process is collected and sent to Unit 220 – Calcium Carbonatation where calcium is mineralized. The residue from the filters from all three trains is combined and dried before being sent to Area 300 – Hydrochloric Acid Leach. Unit 220 – Calcium Carbonatation The calcium carbonatation circuit is designed to mineralize the calcium leached in the ammonium chloride process by converting it to solid calcium carbonate. NH4Cl PLS from Unit 210 – NH4Cl Filtration enters the circuit and is cooled to 86°F (30°C) before being mixed with an ammonium hydroxide solution condensed from the leach reactors’ overhead condensers. The PLS is then contacted with carbon dioxide in the CaCO3 reactor train to mineralize calcium as a carbonate and the resulting slurry is sent to Unit 230 – Calcium Carbonate Dewatering. Excess CO2 is recovered and recycled in the process. Unit 230 – Calcium Carbonate Dewatering The slurry Unit 220 – Calcium Carbonatation is filtered using Belt Filters installed in parallel and the resulting cake is washed using clean water. The wash water is sent to the NH4Cl Mixing Tank located in Unit 200 – NH4Cl Leach while the calcium barren solution continues to Unit 240 – Magnesium Carbonation. The solids sent to area 900 – Sulfate Effluent and to paste backfill. Unit 240 – Magnesium Carbonation The magnesium carbonation circuit is designed to mineralize the magnesium leached in the ammonium chloride process by converting it to solid magnesium carbonate using a metathesis reaction with ammonium carbonate. Barren solution from Unit 230 – Calcium Carbonate Dewatering enters the circuit and is combined with an ammonium carbonate solution, mineralizing the magnesium as a carbonate. The resulting slurry is sent to Unit 250 – MgCO3 Dewatering. Unit 250 – MgCO3 Dewatering The slurry Unit 240 – Magnesium Carbonatation is filtered using Belt Filters installed in parallel and the resulting cake is washed using clean water. The wash water and the magnesium barren are sent to Unit 260/270 – Ammonium Carbonate and Scrubber Units. The solids are sent to paste backfill. Unit 260/270 – Ammonium Carbonate and Scrubber Units The barren solution from Unit 250 – MgCO3 Dewatering and the wash solutions from both Unit 230 – Calcium Carbonate Dewatering and Unit 250 – MgCO3 Dewatering are combined and heated to decompose and vaporize residual ammonium carbonate and excess ammonium hydroxide prior to being recycled in the NHL unit. The vapors are then recovered and mixed with additional ammonium hydroxide and carbon dioxide rich off gas from the NHL Degassing tanks to prepare the ammonium carbonate solution used in Unit 240 – Magnesium Carbonation. Area 300 - Hydrochloric Acid Leach
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 280 | Page The hydrochloric acid leach area is used to leach the rare earth elements, including scandium, away from the niobium and titanium-containing minerals, simplifying the latter elements’ recovery and purification. Elements such as iron, calcium, thorium and other impurities are also recovered in the chloride pregnant leach solution (HCl PLS). A simplified block flow diagram is presented as Figure 14‐4. Source: L3 2026 Figure 14‐4: Area 300 – Hydrochloric Acid Leach Block Flow Diagram Unit 300- HCl Leach The hydrochloric leach circuit is used to leach the REEs, including scandium, away from the Nb and Ti minerals present in the ammonium chloride leach residue. A counter-current system is used to maximize recovery and control the acidity of the PLS prior to extraction in Area 600 – Solvent Extraction. NHL residue from Area 200 – Ammonium Chloride Cycle is combined with 2nd stage leach filtrate, 2nd stage leach wash solution and 1st stage leach wash solution into the HCl leach stage 1 cascade of agitated tanks. External recirculation flows are planned to maintain the leach reactors’ temperatures. Leach slurry from the 1st stage HCl leach step is dewatered in a 2-step hydrocyclone unit. The cyclone underflow is sent to the 2nd stage HCl leach circuit while the overflow is sent Unit 310 – HCl Leach Filtration. In the second stage, the cyclone underflow is combined with hot hydrochloric acid in a cascade of agitated tanks where all leachable elements are extracted into the PLS. External circulation flows are planned to maintain the leach reactors’ temperatures. The residual slurry from the second HCl leach stage is sent to Unit 320 – HCl Leach Dewatering. Unit 310 – HCl Leach Filtration The HCl leach filtration unit is used to ensure no solids are entrained in the PLS prior to the solvent extraction circuits. HCl PLS from the 1st stage leach cyclone in Unit 300 - HCl Leach is filtered in a candle filter with a 3-stage counter-current wash. Each stage is undertaken in batch mode with 2 candle filters operating at different stages to allow for a continuous operation. The residue is sent to the Area 400 – Sulfuric Acid. Unit 320 – HCl Leach Dewatering The HCl dewatering unit is used to recover and wash HCl leach residue prior to the acid baking circuit.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 281 | Page Slurry from the 2nd Stage HCl Leach Reactor cascade, located in Unit 300 - HCl Leach, is washed in a 3 counter-current stages cyclone circuit that includes repulps between each stage. The discharge of the 3rd cyclone stage is then filtered, and the solution is used to repulp the intermediate solids between the 2nd and 3rd cyclone stages. The overflow of the 1st and 2nd cyclone stages is sent back to Unit 300 - HCl Leach and the washed cake is sent to Unit 330 – HCl Residue Drying. Unit 330 – HCl Residue Drying The HCl residue drying unit is used to remove moisture and HCl traces prior to the acid bake circuit using a hollow flight screw conveyor followed by an indirect rotary dryer. Dewatered HCl leach residue from Unit 320 – HCl Leach Dewatering is first partially dried to 95 wt% solids using a hollow flight screw dryer heated with thermal fluid. The partially dried material is then fed to an indirect rotary dryer where it is fully dried. Vapors are collected and sent to Unit 340 – HCl Water Scrubber. Unit 340 – HCl Water Scrubber The HCl water scrubber unit recovers off gases from the HCl unit and cleans them through a water scrubber. The discharge of the scrubber is sent to Area 800 - Chloride Neutralization. The HCl water scrubber is a packed column where vapors and off gasses from the HCl unit are cleaned with water. Water vapor is condensed in the process and the resulting non-condensables are sent to the facility caustic scrubber. Area 400 – Sulfuric Acid The sulfuric acid area is used to convert the Nb and Ti-bearing minerals to leachable sulfate compounds. The resulting sulfates are then leached using water and both the niobium and titanium sulfate compounds are hydrolyzed before being dewatered, calcined and sent to AREA 500 – Chlorination for further processing. A simplified block flow diagram is presented as Figure 14‐5.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 282 | Page Source: L3 2026 Figure 14‐5:Area 400 – Sulfuric Acid Block Flow Diagram Unit 400 – Acid Baking The acid baking unit reacts HCl leach residue, a Nb and Ti rich solid, with concentrated sulfuric acid at elevated temperatures to convert the minerals to solid anhydrous sulfates. Vaporized sulfuric acid is recovered and recycled in the circuit using a 2- step scrubbing circuit. Dry HCl leach residue from Area 300 – Hydrochloric Acid Leach is combined with hot, concentrated sulfuric acid and mixed thoroughly in a pug mill. The pug mill discharge is conveyed in the Acid Bake Kiln where the mixed materials are heated in steps to push the reaction to completion and vaporize any residual liquid sulfuric acid. The reacted materials are then sent to Unit 410 Water Leaching. Vaporized sulfuric acid from the acid bake kiln is recovered through a 2-stage condensing scrubbing system which allows for the recovery of concentrated sulfuric acid while purging the system of water. Unit 410 Water Leaching The water leaching circuit is used to solubilize the sulfate compounds from the acid bake process into an aqueous phase, leaving the insoluble contaminants in the solid residue to be dewatered, washed and sent to sulfate management for paste backfill preparation. Acid bake solids from Unit 400 – Acid Baking are mixed with a heated combination of recycled solutions and reverse osmosis water (ROW). The resulting slurry is pumped into the water leach
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 283 | Page cascade of three agitated tanks, each maintained at a temperature of 176°F (80°C) with a circulation heating loop. The slurry leaving the water leach tanks is sent to Unit 420 – Water Leach Dewatering. Unit 420 – Water Leach Dewatering The water leach dewatering unit is used to filter and wash the water leach residue to maximize niobium recovery. The slurry leaving Unit 410 Water Leaching is dewatered, and the solids are sent through a series of repulp and cyclone operations using a counter-current setup. The water leach PLS from the first cyclone stage is sent to Unit 430 – Hydrolysis while the final repulp is filtered using candle filters. The residue is then washed using acidified hydrolysis barren solution and sent to AREA 900 – Sulfate Effluent for treatment before being sent to paste backfill. A portion of the wash solutions are sent to Unit 410 Water Leaching. Unit 430 – Hydrolysis The hydrolysis unit is used to convert soluble niobium and titanium sulfates compounds into insoluble compounds comprised of a mixture of oxide, hydroxide and oxy-hydroxy-sulfates. Filtered water leach PLS from Unit 420 – Water Leach Dewatering is pumped to a three-stage reaction unit where it is sequentially diluted using hot reverse osmosis water (“ROW”) and steam, converting niobium and titanium sulfates compounds into insoluble compounds comprised of a mixture of oxide, hydroxide and oxy-hydroxy-sulfates. The resulting slurry is sent to Unit 440 – Hydrolysis Dewatering and Filtration. Unit 440 – Hydrolysis Dewatering and Filtration The hydrolysis dewatering and filtration unit is used to recover and dewater hydrolysis solids prior to their calcination. The hydrolysate slurry from Unit 430 – Hydrolysis is filtered and washed using ROW in candle filters. The hydrolysate cake is sent to Unit 450 – Hydrolysate Calcination while the barren solution is partially recycled in Unit 410 Water Leaching and Unit 430 – Hydrolysis. Unit 450 – Hydrolysate Calcination The hydrolysate calcination unit is used to dry the hydrolysate cake and minimize moisture to the chlorination unit. It also allows for a reduction of volatile elements such as sulfur. Hydrolysis cake from Unit 440 – Hydrolysis Dewatering and Filtration is calcined in a rotary calciner and sent to Area 500 – Chlorination. Off gas from the calciner is collected and treated in the plant caustic scrubber. Area 500 – Chlorination The chlorination area is used to convert hydrolysate cake to gaseous metal chlorides and recover each element individually. Niobium and iron are first solidified in a titanium tetrachloride slurry. The titanium tetrachloride is subsequently vaporized, and the mixture of niobium and iron chloride is hydrolyzed. Niobium is recovered as an oxide with iron residuals while iron is sent to the chloride management unit as a ferric chloride solution. The crude titanium tetrachloride solution is then distilled into a pure titanium tetrachloride product.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 284 | Page Products: • Niobium / Iron Oxide (to Pyromet) • Titanium Tetrachloride (TiCl4) A simplified block flow diagram is presented as Figure 14‐6. Source: L3 Process Developments 2026 Figure 14‐6:Area 500 – Chlorination Block Flow Diagram The chlorination unit is used to convert the hydrolysate cake to a mixture of individual metal chlorides using a fluid bed reactor. The metal chlorides exit the chlorinator as gases and are recovered by staged condensation. Iron and niobium are solidified first in a titanium tetrachloride slurry as a crude titanium tetrachloride solution is condensed. Hydrolysate cake is mixed with petroleum coke and fed to the chlorinator, a fluid bed reactor using a sub-stoichiometric chlorine mixture to ensure a minimum amount of unreacted chlorine is lost. Air is also injected into the chlorinator to maintain the temperature of the fluid bed, ensure fluidization and support proper conversion. Cooling water is sparged on the outside of the chlorinator to maintain the reaction below 1,742 °F (950 °C), protecting the equipment.
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 285 | Page The gaseous discharge of the chlorinator is filtered using Electro-Filters and sent to the condensation circuit. The solid residue accumulating in the chlorinator is periodically purged and discarded during shutdowns, prior to the equipment being rebuilt. The chlorination unit operates as a single train, with a full alternate train available. In a typical operation, while one train is in operation, the other train is being maintained. Chlorinator off gases are condensed in a series of three venturi absorbers with decreasing operating temperatures (Nb/Fe Condenser, Primary Condenser, Secondary Condenser), with residual vapors and non-condensable gases discharging to Unit 550 – CO Boiler and FGD Scrubber. The Nb/Fe condenser uses a venturi spray tower without packing to solidify and recover niobium and iron chloride in a titanium tetrachloride slurry. The bottom of the tower is gravity discharged to the clarifier and the underflow is sent to Unit 530 – Nb/Fe Recovery. Excess titanium tetrachloride is sent to the Unit 510 – Crude TiCl4 Treatment. The off gas of the Nb/Fe condenser is sent to the primary condenser. The Nb/Fe condenser cooling circulation loop uses thermal fluid to operate near the boiling point of titanium tetrachloride (277 °F, 136.4 °C). The primary condenser uses a venturi spray tower with packing to condense a titanium tetrachloride solution. The bottom of the tower is sent to Unit 510 – Crude TiCl4 Treatment. The off gas from the primary condenser is sent to the secondary condenser. The primary condenser cooling circulation loop uses cooling water to operate near ambient temperature. The secondary condenser uses a venturi spray tower with packing to condense a titanium tetrachloride solution. The bottom of the tower is sent to the primary condenser. The off gas of the secondary condenser is sent to Unit 550 – CO Boiler and FGD Scrubber. The secondary condenser cooling circulation loop uses an ammonia vaporizer unit to obtain a secondary condenser recirculation operating temperature of 0°F (-18°C). Unit 510 – Crude TiCl4 Treatment The crude TiCl4 Treatment Unit is used to remove most dissolved metals and gases from the TiCl4 prior to its purification using a series of three vaporizers (TiCl4 Degas Tank, Vaporizer #1, Vaporizer #2) and related aero condensers. The first vaporizer is used to de-gas crude TiCl4 from Unit 500 – Chlorination and recycled TiCl4 from unit 520 – TiCl4 Purification by vaporizing it under full reflux conditions to vaporize dissolved non-condensable gases. The TiCl4 Degas tank overflows to the TiCl4 Vaporizer #1 where it is combined with recovered TiCl4 from the Nb/Fe Dryer Condenser and a bleed from the TiCl4 Vaporizer #2. The TiCl4 Vaporizer #1 boils titanium tetrachloride which is fully condensed and pumped to the TiCl4 Vaporizer #2. The TiCl4 Vaporizer #2 boils titanium tetrachloride which is fully condensed and sent to Unit 520 – TiCl4 Purification. Each vaporizer uses fully submerged tube bundles operated with thermal fluid. The second vaporizer in the train (Vaporizer #1) operates at the saturation point of metals dissolved in the crude TiCl4, and as such, as TiCl4 is vaporized and removed from the system, those metals precipitate and form a slurry. A bleed from the vaporizer #1 to the Nb/Fe Condenser in Unit 500 – Chlorination is used to control the solids’ fraction in Vaporizer #1. The third vaporizer in the train (Vaporizer #2) operates below the saturation point of metals dissolved in the crude TiCl4, and as such, as TiCl4 is vaporized and removed from the system, those
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 286 | Page metals concentrate in Vaporizer #2. A bleed from Vaporizer #2 to Vaporizer #1 is used to control the dissolved metals concentration in Vaporizer #2. Unit 520 – TiCl4 Purification The TiCl4 purification unit is used to prepare pure TiCl4 that meets commercial purity specifications using a combination of stripping and distillation. Treated TiCl4 from Unit 510 – Crude TiCl4 Treatment is fed to the TiCl4 Stripper, a packed column used to separate all non- condensable gases dissolved in the treated TiCl4, such as chlorine, nitrogen, carbon monoxide and carbon dioxide through partial reboiling and full reflux. Following the TiCl4 stripper, the TiCl4 is maintained under an inert blanket to ensure no other gases can redissolve in it. Stripped TiCl4 is then fed to the TiCl4 Purification Column, a mixed packed / tray column used to remove metals through distillation of TiCl4, using both reboiling and reflux to control the TiCl4 purity. A bleed from the bottom section is used to control the metal impurities in the column. The bleed stream is sent to Unit 510- Crude TiCl4 Treatment. Mineral oil is also added to the reboiler to raise the vapor pressure of metal impurities. The excess condensate on top of the purification column is sent to storage as a pure TiCl4 product. Unit 530 – Nb/Fe Recovery The Nb/Fe recovery unit is used to recover all Nb from the Nb/Fe TiCl4 slurry as a dry, TiCl4-free solid mixture of niobium chloride and iron chloride. The Nb/Fe Recovery Unit is used to vaporize all TiCl4 from the Nb/Fe TiCl4 slurry in a sloped hollow-flight conveyor. The off gas from the dryer is condensed in the Nb/Fe Dryer Condenser, a venturi scrubber circuit similar in design to the Primary Condenser Circuit. The resulting niobium and iron chloride solids are conveyed to Unit 560 - Nb/Fe Recovery while the recovered crude TiCl4 is pumped to Unit 510 – Crude TiCl4 Treatment and the Vapor is sent to Unit 540 – TiCl4 Vapor Recovery Unit. The Nb/Fe dryer uses hollow screws and thermal fluid to vaporize TiCl4 and dry the niobium and iron chlorides. The Nb/Fe chloride recovery condenser uses a venturi spray tower with packing to condense a titanium tetrachloride solution. Unit 540 – TiCl4 Vapor Recovery Unit The TiCl4 vapor recovery unit is used to recover TiCl4 from various equipment vapor streams before the caustic scrubber discharges to the atmosphere. TiCl4 vapors from the various units are collected and TiCl4 is condensed in a spray tower with packing. The off gas from the vent condenser is then scrubbed with a caustic solution prior to being vented to the atmosphere. The recovered TiCl4 is recycled back to Unit 520 – TiCl4 Purification. Unit 550 – Chlorination Off Gas Management The chlorination off gas management unit is used to treat the chlorination condensation non condensable gases such as chlorine, carbon monoxide and sulfur oxides. Non condensable gases, specifically carbon monoxide from Unit 500 – Chlorination condensation, are first oxidized in the thermal oxidizer before being scrubbed in the Chlorination Wet Flue Gas
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SK-1300 Technical Report Summary – Elk Creek Project, Nebraska NioCorp Developments Ltd. 287 | Page Desulfurization (“FGD”) Scrubber. The FGD scrubber circuit is used to recover sulfur oxides and hydrochloric acid gases by calcium carbonate neutralization. Air is injected in the scrubber to oxidize the calcium sulfite to gypsum, which is recovered from the circuit and sent to paste backfill. The FGD scrubber is then vented to the atmosphere. Unit 560 – Nb Recovery The hydrolysis unit uses heat and dilution to convert niobium chloride into insoluble niobium compounds while solubilizing ferric chloride. The resulting niobium solid is dewatered and calcined into a final product. The niobium and iron chlorides from Unit 530 – Nb/Fe Recovery are sequentially dissolved in wash water from the niobium hydrolysate filter and hydrolyzed using steam injection in a series of three reactors. The resulting slurry is then phase separated using a clarifier to skim the mineral oil present in the chloride solids. The mineral oil mixture is then coalesced, and the aqueous solution is returned to the phase separator. The mineral oil is then sent to Unit 570 -Mineral Oil Conditioning. The Nb hydroxide hydrolysate solids are calcined to generate the niobium oxide product sent to the pyrometallurgy Plant to be converted to ferroniobium (FeNb). Unit 570 – Mineral Oil Conditioning The mineral oil conditioning is used to vaporize any entrained fluids and dry the recycled mineral oil prior to reintroducing it to the chlorination unit. Area 600 – Rare Earth Element Recovery AREA 600 – REE Recovery involves the extraction of scandium, and rare earth elements from the HCl pregnant leach solution (HCl PLS) generated in Area 300 – Hydrochloric Acid Leach and the preparation of a REE solution to feed Area 700 – REE Separation. The REE Recovery Area uses dimethyloctyl dihexyl diglycolamide (DGA-6) diluted in ethyl-hexanol. A simplified block flow diagram is presented as Figure 14‐7.