#1NIOCORP: CRITICAL MINERALS FOR U.S. SUPPLY CHAIN SECURITY OUR MISSION: To accelerate the transition to a lower carbon economy by serving as a reliable U.S. supplier of sustainably produced critical minerals. 161 * WAOOOOOO SOAL DAN CHO CELOR Nio Critical Mineral Security#2Disclaimers & Technical Disclosures Forward-Looking Statements This Presentation contains forward-looking statements within the meaning of the United States Private Securities Litigation Reform Act of 1995 and forward-looking information within the meaning of applicable Canadian securities laws. Forward-looking statements may include, but are not limited to, the anticipated benefits of NioCorp's business combination (the "Business Combination") with GX Acquisition Corp. II ("GXII") and NioCorp's previously announced standby equity purchase facility (the "Yorkville Equity Facility Financing" and, together with the Business Combination, the "Transactions") with YA II PN, Ltd., an investment fund managed by Yorkville Advisors Global, LP (together with YA II PN, Ltd., "Yorkville"), including the ability to access the full amount of the expected net proceeds of the Yorkville Equity Facility Financing over the next three years; NioCorp's ability to receive a final commitment of financing from the Export-Import Bank of the United States ("EXIM"); anticipated benefits of the listing of NioCorp's common shares on Nasdaq; 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 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 expectation and ability to produce niobium, scandium, and titanium at the Elk Creek Project; NioCorp's plans to produce and supply specific products and market demand for those products; the outcome of current recovery process improvement testing, and NioCorp's expectation that such process improvements could lead to greater efficiencies and cost savings in the Elk Creek Project; 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; the completion of the demonstration plant and technical and economic analyses on the potential addition of magnetic rare earth oxides to NioCorp's planned product suite; the exercise of options to purchase additional land parcels; the execution of contracts with engineering, procurement and construction companies; NioCorp's ongoing evaluation of the impact of inflation, supply chain issues and geopolitical unrest on the Elk Creek Project's economic model; and the creation of full time and contract construction jobs over the construction period of the Elk Creek Project. In addition, any statements that refer to projections (including Averaged EBITDA, Averaged EBITDA Margin, and After- Tax Cumulative Net Free Cash Flow), forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. Forward-looking statements are typically identified by words such as "plan," "believe," "expect," "anticipate," "intend," "outlook," "estimate," "forecast," "project," "continue," "could," "may," "might," "possible," "potential," "predict," "should," "would" and other similar words and expressions, but the absence of these words does not mean that a statement is not forward-looking. The forward-looking statements are based on the current expectations of the management of NioCorp and are inherently subject to uncertainties and changes in circumstances and their potential effects and speak only as of the date of such statement. There can be no assurance that future developments will be those that have been anticipated. Forward-looking statements reflect material expectations and assumptions, including, without limitation, expectations, and assumptions relating to the future price of metals, the stability of the financial and capital markets and other current estimates and assumptions regarding the Transactions and their benefits. Such expectations and assumptions are inherently subject to uncertainties and contingencies regarding future events and, as such, are subject to change. Forward-looking statements involve a number of risks, uncertainties or other factors that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to:, those discussed and identified in public filings made by NioCorp with the Securities and Exchange Commission (the "SEC") and with the applicable Canadian securities regulatory authorities and the following: NioCorp's ability to recognize the anticipated benefits of the Transactions, including NioCorp's ability to access the full amount of the expected net proceeds under the Yorkville Equity Facility Financing Agreement over the next three years; unexpected costs related to the Transactions; the outcome of any legal proceedings that may be instituted against NioCorp following closing of the Transactions; NioCorp's ability to receive a final commitment of financing from EXIM on the anticipated timeline, on acceptable terms, or at all; NioCorp's ability to continue to meet Nasdaq and TSX listing standards; NioCorp's ability to operate as a going concern; risks relating to the Common Shares, including price volatility, lack of dividend payments and dilution or the perception of the likelihood any of the foregoing; NioCorp's requirement of significant additional capital; the extent to which NioCorp's level of indebtedness and/or the terms contained in agreements governing NioCorp's indebtedness or the Yorkville Equity Facility Financing Agreement may impair NioCorp's ability to obtain additional financing; covenants contained in agreements with NioCorp's secured creditors that may affect its assets; NioCorp's limited operating history; NioCorp's history of losses; the restatement of NioCorp's consolidated financial statements as of and for the fiscal years ended June 30, 2022 and 2021 and the interim periods ended September 30, 2021, December 31, 2021, March 31, 2022, September 30, 2022 and December 31, 2022 and the impact of such restatement on NioCorp's future financial statements and other financial measures; the material weaknesses in NioCorp's internal control over financial reporting, NioCorp's efforts to remediate such material weaknesses and the timing of remediation; the possibility that NioCorp may qualify as a PFIC under the Code; the potential that the Transactions 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; 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; current and future offtake agreements, joint ventures, and partnerships; NioCorp's ability to attract qualified management; the effects of the COVID- 19 pandemic or other global health crises on NioCorp's business plans, financial condition and liquidity; estimates of mineral resources and reserves; mineral exploration and production activities; feasibility study results; the results of metallurgical testing; 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 industry; 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; 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, or development activities; the 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 of grades of reserves and resources; claims on the title to NioCorp's properties; potential future litigation; and NioCorp's lack of insurance covering all of NioCorp's operations. Should one or more of these risks or uncertainties materialize or should any of the assumptions made by the management of NioCorp prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. All subsequent written and oral forward-looking statements concerning the Transactions or other matters addressed in this communication and attributable to NioCorp or any person acting on its behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this communication. Except to the extent required by applicable or regulation, NioCorp undertakes no obligation to update these forward-looking statements to reflect events or circumstances after the date of this communication to reflect the occurrence of unanticipated events.. Qualified Persons All technical and scientific information included in this Presentation derived from NioCorp's 2022 NI 43-101 Elk Creek Technical Report with respect to mineral resources has been reviewed and approved by Matthew Batty, P.Geo., Owner, Understood Mineral Resources Ltd., and all such information respecting NioCorp's mineral reserves has been reviewed and approved by Richard Jundis, P. Eng., Director of Mining, Optimize Group. Each of Messrs. Batty and Jundis is a "Qualified Person" as such term is defined in NI 43-101. Each of Mr. Batty and Mr. Jundis and their respective firms are independent consultants who provide consulting services to NioCorp. All technical and scientific information included in this Presentation derived from NioCorp's S-K 1300 Elk Creek Technical Report Summary with respect to mineral resources has been reviewed and approved by Understood Mineral Resources Ltd., and all such information respecting NioCorp's mineral reserves has been reviewed and approved by Optimize Group. Understood Mineral Resources Ltd. and Optimize Group are "Qualified Persons" as such term is defined in S-K 1300. All other technical and scientific information included in this Presentation has been reviewed and approved by Scott Honan, M.Sc., SME-RM, NioCorp's Chief Operating Officer. Mr. Honan is a "Qualified Person" as such term is defined both NI 43-101 and S-K 1300. NioCorp Critical Mineral Security#3Disclaimers & Technical Disclosures Financial Information; Non-GAAP Measures Certain financial information and data included in this Presentation is unaudited and may not conform to Regulation S-X. This Presentation also includes certain financial measures not presented in accordance with generally accepted accounting principles ("GAAP"), including, but not limited to, "Averaged EBITDA," "Averaged EBITDA Margin," and "After-Tax Cumulative Net Free Cash Flow." These performance measures do not have a standard meaning within GAAP and, therefore, amounts presented may not be comparable to similar data presented by other companies. These non-GAAP financial measures, and other measures that are calculated using these non-GAAP measures, are not measures of financial performance in accordance with GAAP and may exclude items that are significant in understanding and assessing NioCorp's financial results. Therefore, these measures should not be considered in isolation or as an alternative to net income, cash flows from operations or other measures of profitability, liquidity or performance under GAAP. These non-GAAP financial measures are included in this Presentation because they are key performance measures used in the June 2022 Feasibility Study for purposes of projecting the economic results of the Elk Creek Project, and NioCorp believes that these non-GAAP measures provide useful information to management and investors regarding certain financial and business trends relating to NioCorp's financial condition and results of operations. NioCorp believes that the use of these non-GAAP financial measures provides an additional tool for investors to use in evaluating ongoing operating results and trends and in comparing NioCorp's financial measures with other similar companies, many of which present similar non-GAAP financial measures to investors. These non-GAAP financial measures are subject to inherent limitations as they reflect the exercise of judgments by management about which expense and income are excluded or included in determining these non-GAAP financial measures. The non-GAAP financial measures included in this Presentation are projections. Reconciliations of these forward-looking non-GAAP financial measures to the most directly comparable GAAP financial measures are not provided because NioCorp is unable to provide such reconciliations without unreasonable effort, due to the uncertainty and inherent difficulty of predicting the occurrence and the financial impact of such items impacting comparability and the periods in which such items may be recognized. For the same reasons, the Company unable to address the probable significance of the unavailable information, which could be material to future results. See "Forward-Looking Statements." In addition to the non-GAAP financial measures, this Presentation may contain financial forecasts and projections (collectively, "prospective financial information") of NioCorp. Neither the independent registered public accounting firm of NioCorp audited, reviewed, compiled or performed any procedures with respect to the prospective financial information for the purpose of their inclusion in this Presentation, and accordingly, neither of them expressed an opinion or provided any other form of assurance with respect thereto for the purpose of this Presentation. This prospective financial information constitutes forward-looking statements and should not be relied upon as being guarantees or necessarily indicative of future results. The assumptions and estimates underlying such prospective financial information are inherently uncertain and are subject to a wide variety of significant business, economic, competitive and other risks and uncertainties that could cause actual results to differ materially from those contained in the prospective financial information. See "Forward-Looking Statements." Accordingly, there can be no assurance that the prospective financial information is indicative of future performance of NioCorp or that actual results will not differ materially from the results presented in the prospective financial information included in this Presentation. Actual results may differ materially from the results contemplated by the prospective financial information included in this Presentation. The inclusion of such prospective financial information herein should not be regarded as a representation by any person that the results reflected in such projections will be achieved. The purpose of the prospective financial information is to assist investors, shareholders and others in evaluating the performance of NioCorp's business. The prospective financial information may not be appropriate for other purposes. Information about NioCorp's guidance, including the various assumptions underlying it, is forward-looking and should be read in conjunction with "Forward-Looking Statements" in this Presentation, and the related disclosure and information about various economic, competitive, and regulatory assumptions, factors, and risks that may cause NioCorp's actual future financial and operating results to differ from what NioCorp currently expects. All amounts in this Presentation are expressed in U.S. dollars unless otherwise indicated. Mineral Reserves and Resources Unless otherwise indicated, information concerning NioCorp's mining property included in this Presentation, including mineral resource and reserve estimates, has been prepared in accordance with the requirements of National Instrument 43-101- Standards of Disclosure for Mineral Projects ("NI 43-101") and the Canadian Institute of Mining and Metallurgy ("CIM") "Definition Standards - For Mineral Resources and Mineral Reserves, May 10, 2014" (the "CIM Definition Standards"). Beginning with NioCorp's Annual Report on Form 10-K for the fiscal year ended June 30, 2022 (the "NioCorp Form 10-K"), NioCorp's mining property disclosures included or incorporated by reference in its SEC filings, including mineral resource and reserve estimates, are required to be prepared in accordance with the requirements of subpart 1300 of Regulation S-K ("S-K 1300"). Previously, NioCorp prepared its estimates of mineral resources and mineral reserves following only NI 43-101 and the CIM Definition Standards. On June 28, 2022, NioCorp issued a CIM-compliant NI 43-101 technical report (the "2022 NI 43-101 Elk Creek Technical Report") for the Elk Creek Project, which is available through the website maintained by the Canadian Securities Administrators at www.sedar.com. On September 6, 2022, the Company filed technical report summary for the Elk Creek Project that conforms to S-K 1300 reporting standards (the "S-K 1300 Elk Creek Technical Report Summary") as Exhibit 96.1 to "the NioCorp Form 10-K, which is available through the website maintained by the SEC at www.sec.gov. The 2022 NI 43-101 Elk Creek Technical Report and S-K 1300 Elk Creek Technical Report Summary are based on a feasibility study (the "June 2022 Feasibility Study") prepared by qualified persons (within the meaning of both NI 43-101 and S-K 1300, as applicable) and are substantively identical to one another except for internal references to the regulations under which the report is made, and certain organizational differences. The requirements and standards under Canadian securities laws, however, differ from those under S-K 1300. The terms "mineral resource," "inferred mineral resource," "indicated mineral resource," "mineral reserve," "probable mineral reserve," and "proven mineral reserve" included herein are used as defined in accordance with NI 43-101 under the CIM Definition Standards. While the terms are substantially similar to the same terms defined under S-K 1300, there are differences in the definitions. Accordingly, there is no assurance any mineral resource or mineral reserve estimates that the Company may report under NI 43-101 will be the same as the mineral resource or mineral reserve estimates that the Company may report under S-K 1300. NioCorp discloses estimates of both is mineral resources and mineral reserves. 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. Under both regimes, 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. See Item 1A, Risk Factors in the NioCorp Form 10-K. Reference should be made to the full text of the 2022 NI 43-101 Elk Creek Technical Report and the S-K 1300 Elk Creek Technical Report Summary for further information regarding the assumptions, qualifications and procedures relating to the estimates of mineral reserves and mineral resources as defined under NI 43-101 and S-K 1300, respectively. NioCorp Critical Mineral Security#4Value Proposition: Transition to Net Zero Emissions is Driving Demand Growth for the Critical Minerals at the Focus of NioCorp¹ Niobium Scandium Titanium Magnetic Rare Earths² NioCorp Critical Mineral Security [] ✩ Shovel-ready¹ pure-play critical minerals project with the highest-grade Niobium resource in North America and the 2nd largest indicated rare earth resource in the U.S.² Positioned to become a major U.S. miner / producer of Niobium, forecast to see strong demand growth via rapid-charging solid- state Titanium Niobium Oxide Li-Ion batteries.³ Large prospective U.S. producer of Scandium with a Scandium Mineral Reserve supported by a feasibility study. Scandium has large latent demand in the commercial aviation and automotive sectors.4 NioCorp is conducting technical and economic analyses5 on the potential addition to its planned product suite of several magnetic rare earth oxides, which are forecast to experience large supply shortages because of sharply rising demand.6 Elk Creek Project is strongly focused on environmental, social, and governance values and is already aligned with the Equator Principles ESG Framework. EQUATOR PRINCIPLES 1 Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 2 Indicated mineral resource, based on data from the "Critical Mineral Resources of the United States-Economic and Environmental Geology and Prospects for Future Supply," U.S. Geological Survey, 2017, and from company-issued reports. 3 Source: CBMM. 4 "Scandium: A Market Assessment," ONG Commodities, 2019. 5 As no economic analysis has been completed on the rare earth mineral resource comprising the Elk Creek Project, further studies are required before determining whether extraction of rare earth elements can be reasonably justified and economically viable after taking account all relevant factors. 6 "Rare Earth Magnet Market Outlook to 2035," Adamas Intelligence, 2022.#5Stellantis and NioCorp Sign Non-Binding Rare Earth¹ Offtake Term Sheet Term Sheet Also Envisions a Possible Strategic Investment by Stellantis in NioCorp's Elk Creek Critical Minerals Project ALDE NioCorp Critical Mineral Security RAM Working toward a definitive agreement for a 10-year offtake contract for high-purity, separated rare earth oxides: NdPr, Dysprosium, and Terbium.1 Final volumes to be determined. NioCorp and Stellantis collaborating on the larger permanent RE magnet supply chain. ¹ NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. Final determination of possible rare earth production can be made only after work related to a mineral reserve update, additional engineering, updated project capital and operating cost estimates, and other required information is produced for publication in a new Feasibility Study. 2 Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 5#6EXPORT-IMPORT BANK OF THE UNITED STATES VETERANS ADMINISTRATION OFFICE OF CONSTRUCTION MOCAPD NioCorp US Export-Import Bank Considering up to $800M in Debt Financing for NioCorp March 2023: EXIM sends NioCorp a formal Letter of Interest for up to $800 in debt financing to the Elk Creek Project 811 June 2023: NioCorp applies to EXIM for financing 70 October 2023: EXIM notifies NioCorp that its application has been approved by the first of three reviews by the Bank's Transaction Review Committee, an important milestone in the application's progress. EXPORT IMPORT BANK. EXPORT-IMPORT BANK OF THE UNITED STATES VETERAM ADMINISTRATION OFFICE OF CONSTRUCTION 6#7NioCorp Critical Mineral Security میرا Listing on the Nasdaq Stock Exchange (Ticker: NB) # > 92% rare earth recovery rates achieved at demonstration plant 1,2 Additional Milestones Achieved E NioCorp added to FTSE / Russell Index Higher niobium recovery rates achieved at demonstration plant 1,2 8 Launched phased commercialization of Aluminum- Scandium master alloy C 2x titanium recovery rates achieved at demonstration plant 1,2 A Geotechnical drilling campaign recently completed 3) Front-page New York Times story on Project ¹ NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. 2 Final determination of niobium and titanium production levels and possible rare earth production can be made only after work on a mineral reserve update, additional engineering, updated project capital and operating cost estimates, and other required information is produced for publication in a new Feasibility Study.#8NioCorp's Expected Mining Operations Designed from the Start with Sustainability in Mind Fully aligned with Equator Principles, an auditable ESG framework Zero process water discharge facility Additional protection of groundwater resources through artificial ground freezing and grouting NioCorp Critical Mineral Security Local employment and support local businesses Recycling of reagents Avoidance of permanent impacts to Federally Jurisdictional Waters Utilizing tailings as underground mine backfill#9NioCorp Critical Mineral Security MARKETS 9#10Wider Adoption of Critical Materials is Supply Constrained The Problem Lack of secure and reliable long-term supply is preventing fulfilment of latent market demand and realization of environmental benefits resulting from existing applications and from significant new technologies. This is due to: Concentrated sources of supply for Niobium, Scandium, and separated magnetic rare earth oxides. Extremely scarce and limited Scandium supply. Some supply chains have politically sensitive and unreliable supply locations, particularly rare earths. Environmental impacts from many of these sources are greater than in the U.S. NioCorp Critical Mineral Security Current Annual Niobium, Scandium, and Magnetic REE Oxide Production¹ Magris Resources 7 kt CBMM 66 kt CMOC 10 kt Rio Tinto 3t - 12t Estonia 0.4kt Russia 3t Niobium Production Scandium Production Magnetic REE Oxides The U.S. is dependent on foreign suppliers for most of NioCorp's critical minerals. China • 10t Sc₂03 • 50t Sc₂03 ¹ Corporate reports and company information, ONG Commodities, USGS, Adamas Intelligence 2 Reported by USGS as production capacity, not necessarily production. raw material2 China 52kt Philippines 7.5t Malaysia 5kt 10#11The Solution O Reliable, Low-Risk U.S. Supply is Key to Securing Energy Transition NoCorp Illustration of NioCorp's planned Elk Creek Facility Significant production volumes planned for Niobium, Scandium, Titanium from a low-risk jurisdiction.¹ NioCorp is also conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite: O Diversifies global supply O Creates reliable and meaningful Scandium supply volumes (~100t per annum) Potentially provides non-Chinese rare earths for expansion of renewables and electrified vehicles NioCorp Critical Mineral Security Underground mineral source and environmentally responsible processing creates sustainable production solution.¹ The Elk Creek Project is anticipated to be able to supply some of the world's largest industries and sustainable technologies with Made-in-USA critical minerals produced in a low-impact, sustainable manner. Electrified Transportation Aerospace Clean Energy Mega Infrastructure Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 11#12Niobium 88% of the world's Niobium is produced in only one country¹ - Brazil - which increases supply chain risk and has forced the U.S. Government to stockpile Niobium. O O O O NIOBIUM: A Critical Supply Risk To The U.S. Market growth is expected to rise sharply with the expected use of niobium in next-generation Lithium- Ion batteries, which enables faster battery charging.² Light-weighting of transportation systems and strengthening of bridges and mega-infrastructure projects are expected to drive additional long-term growth. Highly liquid global market with many users and a growing number of applications. Global Niobium Supply =75 kt per annum¹ NioCorp Critical Mineral Security CBMM CMOC ■ Magris Global Niobium Sales by Sector² $3.3bn per annum¹ ■Construction ■Automotive and Transport Aerospace and Defense Oil and Gas ■ Other Global Niobium Demand Drivers Stronger and lighter steels for buildings & infrastructure mega-projects 0.025% Niobium in the steel of the Millau Viaduct bridge reduced the weight of steel and concrete by 60% in the overall project.³ Growing demand for lighter weight and more fuel- efficient cars, trucks, and buses 300 grams Nb reduces the weight of mid-size car by 200 kg and increases fuel efficiency by 5%.³ Next Generation Niobium- Lithium-Ion Batteries Significant potential demand. CBMM expects nearly 50 ktpa Nb Oxide sales by 2030.³ 1 "Niobium Outlook to 2030," Roskill, 2020. 2 Source: CBMM. 3 Source: Niobium.Tech (CBMM). 12#13Scandium Forecast demand (117 tpy by 2026) greatly exceeds current supply (25 tonnes/year)¹ and exceeds NioCorp's potential annual scandium production. 140 120 Momentum building in the market, with new pilot production from Rio Tinto² and planned production from others. 100 ● Potential in EV/Automotive: Net pounds of aluminum per light duty vehicle is forecast to increase from 459 lbs. in 2020 to 570 lbs. in 2030,³ representing a large potential for scandium use in aluminum-scandium alloys, even at low overall penetration; just 10% of this volume using 0.1% scandium would mean 700 tons/year scandium demand.¹ 80 60 40 ■ 20 " 0 SCANDIUM: Limited Current Supply But Very Large Latent Demand Solid oxide fuel cell use of Scandium (-22 tpy) forecast to grow at 23% CAGR¹ Aerospace + industrial use in 2022 (-5 tpy) forecast to reach 50tpy over next 5 years¹ 2021 Base Case: Global Scandium Demand, Unconstrained by Supply Availability NioCorp Critical Mineral Security 2022 2023 Bloom Energy (SOFCs) Aerospace Industrial Other 2024 117 tpa 2025 2026 Source: ONG Commodities Ltd., 2021 Global Scandium Demand Drivers Increasing focus on lighter-weight and more fuel efficient commercial jets Approximately $2M of scandium in a single airliner offers an estimated $27M million of net present value in fuel savings.4 1 ONG Commodities Ltd. 2 Rio Tinto. 3 Advanced Casting Research Center. Development of lighter-weight and more fuel efficient railway cars and large transport One of the world's largest aluminum companies has already produced Al-Sc alloy rail hopper cars.5 Weight reduction in EV components is a high priority for automakers. IEA forecast 25% CAGR growth in demand for EVs to 2030.6 4 Company estimate. 5 Aluminum International Today, Jan. 25, 2022. 6 EA Global EV Outlook 2022. 13#14Titanium O 60 Demand for titanium metal is forecast to growth by a 6.8% CAGR between 2022 and 2030, driven primarily by increasing demand in defense and industrial segments.¹ '000 tonnes 20 Global markets for aerospace-grade titanium metal have tightened in recent years because of increased demand and supply chain pressures resulting from the Ukraine conflict with Russia, the world's largest supplier. The last titanium sponge plant in the US closed in 2020. NioCorp plans to make titanium dioxide and/or TiO₂, a high-purity product used in the two largest titanium market segments: titanium dioxide pigments and titanium metal. 36 2%1 40 15% 26% 57% 0 r TITANIUM: Tight Global Supply Because of Rising Demand + War in Europe 41 40 NioCorp Critical Mineral Security +2.6% 41 46 9107 49 50 2017 2018 Historic and Forecast Demand for Titanium Metal 43 2019 21 T 27 4% 27% 30% T 40% T PRIMARY TITANIUM (TITANIUM SPONGE) PRODUCTION CAPACITY 33 34 T 5,000 Primary Titanium Sponge Production Capacity T 41 +6.8% 43 45 47 Credit: IperionX, 2023, based on USGS Survey. Locations approximate. 43 T 45 19% 32% -2% 47% 7 Emerging +1.5% Military +2.3% Industrial +2.6% Aerospace +0.2% Source: TiCl4 Market Analysis, conducted for NioCorp by TZMI, 2023. Global Titanium Demand Drivers Demand in commercial aviation Production backlogs at Boeing underpin a significant portion of US demand for titanium metal and therefore titanium sponge.¹ Increased use in advanced military fighter jets For example, the F-22 utilizes 9,000+ lbs. of titanium, comprising approximately 42% of the aircraft's weight.² ¹ TIO₂ Market Analysis for NioCorp, performance by TZMI, 2023. 2 Cotton, James D., et al. "Titanium Alloys on the F-22 fighter airframe." Advanced Materials & Processes, vol. 160, no. 5, May 2002. 3 Research and Markets, 2023. Extensive consumption of TiO₂ across multiple markets Titanium dioxide demand is expected to grow at 6.3% CAGR from 2023 to 2030.³ 14#15Magnetic Rare Earth Elements O NioCorp has signed a non-binding term sheet with Stellantis NV for possible sale of these magnetic rare earth oxides: NdPr, Dy, and Tb.² Tonnes O Global magnetic REE oxide consumption value is forecast to increase 3x by 2035, from US$15.1 billion in 2022 to US$46.2 billion by 2035.¹ Global REE markets are forecast to under-produce NdPr, Dy, and Tb oxides from 2022 onward unless significant new supplies are brought online.1¹ Historical global consumption and forecast demand for magnet rare earth oxides by end-use category 250,000 200,000 150,000 MAGNETIC RARE EARTHS: Global Demand to Grow 3X by 2035¹ 100,000 50,000 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 NioCorp Critical Mineral Security 2028 2029- 2030 2031 2032 2033 2034 2035 Automotive (Passenger & commercial EVs; micromotors / sensors/speakers; other e-mobility) Consumer Electronics, Appliances, Power Tools Wind Power Industrial Applications Miscellaneous Growth Rates for Magnetic REE Consumption by Sector from 20222035¹ Sector Retail and Commercial EV Traction Motors Direct drive and hybrid drive wind power generators Automotive micromotors, sensors, and car speakers Industrial motors, pumps, generators, robotics Electronics, appliances, power tools All other uses CAGR 14.0% 13.0% 4.9% 4.2% 4.1% 12.6% Automotive market requires significant REEs with EV traction expected to drive a 14.1% CAGR¹ Global Magnetic REE Demand Drivers GHG reductions driven by greater use of electric vehicles and other tech Demand for magnetic rare earths is expected to grow by more than 150% from 2020 to 2030.¹ ed) Demand for direct drive and hybrid drive wind turbines requires significant REE volumes Demand expected to grow at 13.0% CAGR by 2035.¹ Acute global supply shortages of magnetic REES are forecast Shortages of rare earth alloys for magnets forecast to be equal to one- third of the total market by 2035.¹ 1"Rare Earth Magnet Market Outlook to 2035," Adamas Intelligence, 2022. All REE calculations carried on an elemental basis. 2 NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. Final determination of possible rare earth production can be made only after work related to a mineral reserve update, additional engineering, updated project capital and operating cost estimates, and other required information is produced for publication in a new Feasibility Study. 15#16O U.S. Government: The Products That NioCorp Intends to Produce¹ Are Critical All of NioCorp's planned products have been singled out as "critical minerals" by the U.S. Government. The products NioCorp intends to focus on - including potentially rare earths² - include the top 3 most critical minerals to U.S. national security, according to defense experts.³ Billions of dollars now available for investments in critical minerals processing from U.S. gov't agencies. New federal law provides a 10% production tax credit applicable to all of NioCorp's planned critical minerals.4 U.S. electric vehicle tax credit now contingent on increasing content of U.S.-produced critical minerals.4 NioCorp intends to focus on the TOP 3 MOST CRITICAL MINERALS1,2 NioCorp Critical Mineral Security Mineral 1 Rare Earths² 2 Scandium 3 Niobium 24 Titanium (sponge metal) Criticality Score 10 10 9 U.S. Net Import Reliance 100% 100% 100% 75% ¹ Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 2 NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. 3 Business Executives for National Security, 2020. 4 Inflation Reduction Act of 2022, signed into law by President Biden on August 16, 2022. 16#17NioCorp Critical Mineral Security Aluminum-Scandium Master Alloyal 17#18The Power of Aluminum-Scandium Master Alloy No need to quench cast parts High specific strengthening effect Inhibition of recrystallization Grain size refinement Better fatigue life Improved resistance to hot cracking and improved corrosion resistance Enables better parts recycling and circular economics for manufacturers NioCorp Critical Mineral Security Superior Grain Refinement: Aluminum Alloy without scandium (left) and Al-Sc (right)¹ 1 Source: Metallica Minerals. 18#19n NioCorp's Phased Commercialization of Aluminum-Scandium Master Alloy Scandium mining NioCorp Critical Mineral Security NioCorp Goal: To produce in the U.S. both scandium oxide and aluminum-scandium master alloy. NioCorp SC₂03 oxide AISC Master Alloy High margin capture Aluminum industry Tier 1 & 2 manufacturers Automotive Manufacturers 19#20First Al-Sc Master Alloy Ingots Produced Successful pilot-scale production of two 1-kg Al-Sc alloy ingots recently at testing facility in Pennsylvania. Ingots contain 2% scandium by weight, which is considered industry standard. Using metallothermic reduction of scandium chloride, which involves: - NioCorp Critical Mineral Security Less environmental impacts Very high prospective yield Separates Sc reduction and alloying with Al into 2 steps NioCorp's Al-Sc Master Alloy pilot-scale testing at Creative Engineers in New Freedom, Penn. 20#21Scandium Market Development Initiative Recently established NioCorp Technologies Ltd in the UK Effort focused on developing Al-Sc mass market applications for light-weighting and recycling of automotive components Partnering with a leading UK university to undertake advanced Al-Sc research Working closely with leading automotive OEMs, Tier 1 suppliers and specialist manufactures Undertaking rapid prototyping to build early track record and accelerated market adoption NioCorp Critical Mineral Security 8. EXAMPLE: Cast Node on Battery Box requires strength, corrosion resistance, weldability 21#22Phased Commercialization Deployment Progression Pilot-Scale Manufacturing Goal: production of three 1-kg ingots of 5% wt.% scandium. Work underway now in New Freedom, Penn. Scandium chloride obtained from various commercial sources. NioCorp Critical Mineral Security Commercial Demonstration Scale to production of 10-kg and then to 100-kg ingots. Work to be performed at 3rd party ingot casting facility in the US, which helps to provide a blueprint for commercial-scale master alloy plant with 100 tonnes (contained Sc) per year production capacity delivered at end of demonstration. Scandium chloride from various commercial sources. Full-Scale Commercialization Facility co-located with Elk Creek facility in Nebraska to take advantage of existing infrastructure. Scandium from Elk Creek Project in Nebraska. 22#23Automotive NioCorp is now working with automotive manufacturers to explore different aluminum- scandium alloy chemistries to be used for prototype parts for EV and ICE vehicles. Application Examples Cast Node on Battery Box Tesla Model 3 Ford Mach-g NioCorp Critical Mineral Security Industrial Sectors Seeking Greater Access to Scandium Alloys Extruded Bumpers WWW MEB Jaguar -Pace Battery Enclosures Commercial Aviation Commercial airlines intensely interested in light-weighting jets to reduce emissions. Al-Sc alloy parts have already been developed that can be swapped out with current alloy parts to reduce weight. Application Examples APWorks, and Airbus subsidiary, developed a lightweight aircraft bulkhead partition using Scalmalloy, an aluminum- magnesium-scandium alloy. Defense/Space DoD interested in aluminum- scandium alloys in land-, air-, sea-, and space systems. NioCorp, DoD, and Congress working to potentially accelerate our current Al-Sc master alloy commercialization effort. Application Examples 5G / Communications 5G networks require improved RF filtering. Designs incorporating scandium-aluminum-nitride are much more efficient. This requires high-purity scandium metal for production. Application Examples Scandium Sputtering Target 23#24NioCorp Critical Mineral Security THE ASSET 24#25Ferroniobium Resource: 970,300 tonnes No production in the U.S. Highest grade Niobium project under development in N.A.¹ NioCorp Critical Mineral Security Critical Minerals in the Elk Creek Resource¹ Critical Minerals Scandium Oxide Resource: 11,337 tonnes No production in the U.S. Largest planned producer in N.A. Titanium Dioxide (or TiC14)² Resource: 4,221,000 tonnes High import reliance for U.S. Is expected to be produced by NioCorp as a co-product. Magnetic Rare Earths Neodymium- Praseodymium Oxide³ Resource: 125,800 tonnes No production in the U.S. Elk Creek Project contains the 2nd largest indicated NdPr Mineral Resource in the U.S.4 Dysprosium Oxide³ Resource: 9,100 tonnes No production in the U.S. Elk Creek Project contains the 2nd largest indicated Dysprosium Mineral Resource in the U.S.4 Terbium Oxide³ Resource: 2,300 tonnes No production in the U.S. Elk Creek Project contains the largest indicated Terbium Mineral Resource in the U.S.4 Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 NioCorp is currently assessing the feasibility of producing Titanium Tetrachloride in addition to, or in lieu of, Titanium Dioxide. Final determination of possible rare earth production can be made only after work related to a mineral reserve update, additional engineering, updated project capital and operating cost estimates, and other required information is produced for publication in a new Feasibility Study. 3 NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. 4 Indicated mineral resource, based on data from the "Critical Mineral Resources of the United States-Economic and Environmental Geology and Prospects for Future Supply," U.S. Geological Survey, 2017, and from company-issued reports. 25#26Niobium ThyssenKrupp Metallurgical Products² 50% of NioCorp's planned ferroniobium production for first 10 yrs.¹ Pricing set at 3.75% discount to Argus Metals index pricing for ferroniobium NioCorp Critical Mineral Security Offtake Agreements for Products NioCorp Intends to Produce¹ 75% of NioCorp's planned Ferroniobium production already contracted for the first 10 years of operation CMC Cometals³ 25% of NioCorp's planned ferroniobium production for first 10 yrs. ¹ Pricing set at 3.75% discount to Argus Metals index pricing for ferroniobium Scandium ~12% of NioCorp's planned production already contracted for the first 10 years of operation Traxys North America LLC4 Up to 12 tonnes per year of NioCorp's planned scandium production over 10 yrs.¹ Largest commercial sales agreement for Scandium known to have been executed. ¹ Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 2 Contract with Thyssen Metallurgical Products GmbH, dated November 10, 2014. 3 Contract with CMC Cometals, dated June 13, 2016, which was subsequently assigned to Traxys Cometals USA, LLC. Rare Earths5 Stellantis, 3rd largest global automaker, and NioCorp executed a non-binding term sheet in July 2023 on the prospective sale of NioCorp's magnetic rare earth oxides. 4 Contract with Traxys North America LLC, dated October 3, 2018. 5 NioCorp is currently conducting technical and economic analyses on the potential addition of magnetic rare earth oxides to its planned product suite. Final determination of possible rare earth production can be made only after work related to a mineral reserve update, additional engineering, updated project capital and operating cost estimates, and other required information is produced for publication in a new Feasibility Study. 26#27DE NioCorp Critical Mineral Security ZACHRY Surface Processing Facilities EPC DAHROUGE CONSULTING LTD. World Class Development Partners Geology olsson Project Permitting Cementation AUNDERSTOOD Mine Development EPC Mineral Resource MINERAL RESOURCES LTD. [²0 Process Development Mineral Reserve Process Development OPTIMIZE GROUP COMMUNICATE COLLABORATE INNOVATE NioCorp's global team includes some of the world's best in their fields. 27#28Nio Corp Critical Mineral Security THE ELK CREEK PROJECT 28#29Crawford No Scottsbluff +3424 Chadron Kimball Gordon. Rushville. Patridgeport Niobrará Alliance SAND Hyannis HILLS NioCorp Critical Mineral Security Middle Imperial Lake McConaughy Ogatata 80 Thedford Benkelman Elk Creek Project Location & Layout¹ The Elk Creek Project is centered within one 640-acre section of all private land. Valentine North North Platte McCook River Ainsworth Dunning Lou Loup South Loup Lexingt Broken Bow Ansley Kearney O'Neilon Burwell Holdrege Minden Alma Republican Lewis and Clark Lake Neligh Loup Hastings A Little Norfolk Grand Island R River Blue Superior Work Elk Creek Project Location Hartington South Sioux City Wayne Columbus West Point Wahoo Fairbury Blait Fremont Omaha Bellevue Lincoln Nebraska City Falls City • 105 km (65 miles) southeast of Lincoln, Nebraska (the state capital) • 129 km (80 miles) south of Omaha, Nebraska. • 3 miles west of Elk Creek, Nebraska and 6 miles south of Tecumseh, Nebraska. Tailings 2 Pond Tailings 3 Salt Cell 1 Resource Projection W PLO P Fill Substation doc Pyro Acid Hydromet HCI Waste e Ore Mineral Processing Dry Production TE Backfill Life Estates Bunker Pond Topsoil Tailings 1 Pond 2 a Vent Highway 62 Highway 50 Excellent location near highways, utilities, and supporting infrastructure. ¹ Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 29#30Mineral Cut-off Resource NSR Classification (US$/t) Indicated Inferred Mineral Resource and Reserves¹ 180 Mineral Reserve Classification Probable 180 Tonnage Grade (000's Mt) (Nb₂05%) 188.8 108.3 Tonnage (000's t) 36,656 0.51 0.39 NioCorp Critical Mineral Security Grade (Nb₂05%) Initial Operational Footprint (640 acres) 0.811 Grade (TiO₂%) 2.24 1.92 Gra (Sc g/t) NOTE: Mineral Resources shown above are reported inclusive of the Mineral Reserve. Grade (TiO₂%) 2.92 Mineral Reserves and Mineral Resources¹ 60.06 52.28 Grade (TREO%) 0.34 0.38 Grade (Sc g/t) 70.2 NOTE: For a complete description of the Elk Creek Project's Mineral Resources and Mineral Reserves, please refer to the Mineral Reserve and Mineral Resource slides in the Appendix of this presentation. Highway 62 Highway 50 Pisal Elk Creek Elk Creek NioCorp's mineral reserve lies within a much larger carbonatite footprint. ¹ Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. Carbonatite Boundary (~7,800 acres) 30#31Key Permits Obtained The Elk Creek Project has secured key federal, state, and local permits required to proceed to the start of construction once project financing is obtained. Construction Air Permit secured from the State of Nebraska. A Special Use Permit secured from Johnson County, Nebraska, the key local land use permit for the Elk Creek Project. The Elk Creek Project is designed to avoid impacts to federal jurisdictional waters and other features and does not require a federal permit under NEPA. NioCorp Critical Mineral Security 31#321 2 3 4 L? 5 NioCorp Critical Mineral Security Strong State & Local Support The Elk Creek Project is located exclusively on private land with extensive nearby infrastructure (roads, rail, water, and utilities). The Elk Creek Project enjoys strong community support as well as state and local government support. Nebraska Governor Pete Ricketts nominated the Elk Creek Project as a "National High-Priority Infrastructure" Project to the White House.¹ Elk Creek Project is slated to receive approximately $200 million in tax benefits from the State of Nebraska over its first 10 years of operation.² Nebraska is reducing its state corporate income tax over time from 7.5% in 2022 to 3.99% in 2027³ Estimated Economic Benefits and New Tax Revenue Generated by the Elk Creek Project 4 Direct full-time, permanent jobs created5 Indirect jobs created or supported Peak construction-related jobs5 Cumulative operating expenses over project life5 Employee payroll over project life (included in cumulative operating expenses above)5 New tax revenue to state and local government over project life5 Royalties paid to Nebraska landowners over project life5 ~450 $6.59 billion ~2,117 1,232 $1.1 billion $608 million The Elk Creek Project enjoys strong and broad-based state and local support. $300 million ¹ https://www.mining.com/nebraska-governor-says-niocorps-elk-creek-high-priority-project/ 2 Contract signed July 23, 2021 with the State of Nebraska under the Nebraska Advantage Act. 3 https://governor.nebraska.gov/press/governor-pillen-signs-historic-tax-cuts-package #:~:text-Reduces%20the%20top%20individual%20and,care%2C%20for%20families%20and%20providers 4 2022 NI 43-101 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 5 2022 Elk Creek Technical Report. Estimates account for tax benefits NioCorp expected to receive from the Nebraska Advantage program. 6 Additional jobs created or supported was estimated using the Economic Policy Institute's Employment Multiplier for Metal Ore Mining, https://www.epi.org/publication/updated-employment-multipliers-for-the-u-s-economy/ 32#33NioCorp Critical Mineral Security $2.8B Pre-Tax NPV 68% Averaged Annual EBITDA² Margin over Run of Mine³ Elk Creek Feasibility Study¹ Highlights (not including REE production) 29.2% Pre-Tax IRR $21.9B Gross Revenue over Mine Life $2.35B After-Tax NPV $10.9B After-Tax Cumulative Net Free Cash Flow² over Run of Mine³ 27.6% After-Tax IRR $1.14B Total Net Up- Front CAPEX $403M Averaged Annual EBITDA² over Run of Mine³ 38 Yrs. Mine Life ¹ Based on the 2022 NI 43-101 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 See "Financial Information; Non-GAAP Measures" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 3 "Run of Mine" is defined as the period of time during which the mine is fully operational and excludes the periods of time when the mine is conducting its initial production ramp or is ramping down to closure. 33#34Elk Creek Project Expected to Deliver Significant Cash Flow Over 38-Year Life 2022 Elk Creek Feasibility Study Economic Results (not including REE production) Pre-Tax Net Present Value (NPV) (8% discount) Pre-Tax Internal Rate of Return (IRR) After-Tax NPV After-Tax IRR After-Tax Payback Period from Production Onset (years) Total Upfront CAPEX Mine Life (years) Life of Mine ("LoM") Gross Revenue ($M) Niobium Scandium Titanium Averaged Annual EBITDA over LoM² Averaged EBITDA Margin over LoM (EBITDA as % of total revenue)² Averaged Annual Operating Cash Flow over LoM² Average Annual Operating Cost, LOM (OPEX) (US$/t) Averaged Annual EBITDA over Run of Mine ("RoM") ² Averaged EBITDA Margin over RoM (EBITDA as % of total revenue) 2 Averaged Annual Operating Cash Flow over RoM² Effective Tax Rate Elk Creek Project Metrics Summary¹ NioCorp Critical Mineral Security (US$ Millions) $2,819 29.2% $2,350 27.6% 2.69 $1,141 38 $21,900 $7,968 $13,504 $427 $397.5 69% $337 ($195.9) $403 68% $340 16.4% $M US $500 $400 $300 $200 $100 $0 ($100) ($200) ($300) ($400) ($500) Elk Creek Project After-Tax Metrics Year of Operation Capex Free Cash Flow-Payable Nb ¹ Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 See "Financial Information; Non-GAAP Measures" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 6,000 4,000 2,000 0 -2,000 -4,000 -6,000 Payable Nb in tonnes 34#35Mark A. Smith, P.E. Executive Chairman, President and Chief Executive Officer Mr. Smith joined NioCorp as CEO and Chairman in 2013. He has 40+ years of experience in the mining and mineral processing industries. Formerly, he was President, CEO & Director of Molycorp; CEO and Director of Largo Resources; CEO and President of Chevron Mining; and Director of Companhia Brasileira de Metalurgia e Mineracao Ltd. ("CBMM"), the largest niobium producer in the world. Mr. Smith also serves as CEO and Chairman of IBC Advanced Alloys and US Vanadium LLC. He holds a B.Sc. degree in engineering from Colorado State University and a J.D. (cum laude) from Western State University, College of Law. NioCorp Critical Mineral Security Management Team Scott Honan, MSc, SME-RM Chief Operating Officer, NioCorp President, Elk Creek Resources Corp. Mr. Honan joined NioCorp in 2014. He has 29+ years of experience in the niobium, base metals, gold and rare earth industries. He served as General Manager and Environmental Manager and Vice President Health, Environment, Safety and Sustainability at Molycorp. Scott is a graduate of Queen's University in Mining Engineering in both Mineral Processing (B.Sc. Honors) and Environmental Management (M.Sc.) disciplines. He is a registered member (No. 04231597) of the Society for Mining, Metallurgy & Exploration (SME). Neal Shah, BSME, MBA Chief Financial Officer & Corporate Secretary Mr. Shah has been with NioCorp since 2014. With nearly 20 years of experience in various industries as diverse as high-tech to rare earths, Neal's past experience includes senior positions with Molycorp, Intel, IBM, Boeing, and Covidien. He a graduate of the University of Colorado's Mechanical Engineering program (BSME) and Purdue University's Krannert School of Management (MBA). Jim Sims Chief Communications Officer Mr. Sims joined NioCorp in 2015 and has 25+ years of experience representing companies in mining, chemical, manufacturing, utility, and renewable energy sectors, including Dow Chemical, Calpine, FMC, MidAmerican Energy, Danaher, and others. He was VP of Corporate Communications for Molycorp and is the former head of the U.S. Geothermal Energy Association, the Western Business Roundtable, and the Rare Earth Technology Alliance. A former White House staffer, Jim served for 11 years in the U.S. Senate, including as a Chief of Staff, and held a top- secret security clearance. He is an honors graduate of Georgetown University. A management team with decades of combined experience in mineral production. 35#36Mark A. Smith, P.E. Executive Chairman, President and CEO Mr. Smith has over 40 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, and later as CEO, for Largo Resources Ltd. Mr. Smith has also served on the board of directors of IBC Advanced Alloys Corp., a leading beryllium and copper advanced alloys company, 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, Inc., a rare earths producer, where he was instrumentally involved in taking it from a private company to a publicly traded company with a producing mine. Prior to Molycorp, Mr. Smith was the President and CEO of Chevron Mining Inc. He 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. 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. NioCorp Critical Mineral Security Board of Directors (slide 1 of 2) Nilsa Guerrero-Mahon Audit Committee Chair 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 NG Mahon Business Consulting, LLC. In addition, Ms. Guerrero-Mahon was appointed to the Board 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 on the Board of the State of Colorado Division of Securities. From 2016 to August 2019, she served on the board of directors of Centura Health Mountains & North Denver Operating Group, the largest division in the Centura Health Care System. From 2014 to 2016, she served as the Vice Chair of the board of directors and Chaired the Strategy Committee at St. Anthony Hospital. From 2009 to 2017, Ms. Guerrero- Mahon served as a gubernatorial appointed Board Member of the State of Colorado Financial Services Commission. Among other prior positions, from 2004 to 2007, she was the Global Services Controller at Microsoft Corporation, overseeing internal controls and corporate finance activities. Michael J. Morris Lead Director Mr. Morris was formerly the Chairman of the board of directors of Heritage Oaks Bankcorp, the holding company of Heritage Oaks Bank. When Heritage Oaks Bank merged with Pacific Premier Bancorp on April 1, 2017, Mr. Morris became a member of the Pacific Premier Bancorp's board of directors, a position he held until May 31, 2020. He joined Heritage Oaks' board of directors in January 2001 and assumed the board's chairmanship in 2007. In addition, Mr. Morris has worked since 1972 at Andre, Morris & Buttery, a professional law corporation, where he serves as Senior Principal and has served as Chairman of the board since 2005. From 2000 to late 2006, Mr. Morris served on the board of Molycorp, a rare earths producer, which at the time was a wholly owned subsidiary of Unocal and then Chevron Mining. Mr. Morris was the only independent director of Molycorp at that time. Mr. Morris is a graduate of Georgetown University and received his law degree from the University of San Francisco School of Law. He has practiced business and environmental law for over 40 years. Mr. Morris served as a member of the Board of Governors and Vice President of the State Bar of California. He served as a 1st Lieutenant in the U.S. Army from 1970 to 1972. David C. Beling, P.E. Mr. Beling is a Registered Professional Mining Engineer with 58 years of project and corporate experience. He has served as a director on the boards of 14 mining companies starting in 1981, including NioCorp since 2011. Mr. Beling is the owner of D.C. Beling & Assoc., LLC, which provides strategic advisory, project, and corporate development services to the mining industry. His previous employment and consulting included 14 years with five major mining companies and then 44 years with 30+ U.S. and Canadian junior mining companies. He was the President, CEO, and Director of Bullfrog Gold Corp. from 2011 until October 2020; and the Executive Vice President and COO of Geovic Mining Corp. from 2004 through 2010. Mr. Beling has examined, significantly reviewed, or been directly involved with 90 underground mines, 136 open pit mines, and 174 process plants in the global metal, energy, and industrial mineral sectors. 36#37Anna Castner Wightman A sixth generation Nebraskan and a graduate of Nebraska Wesleyan University, Ms. Wightman serves as a Senior Director of Government Relations for First National Bank of Omaha, Nebraska, a position she has held since 2000. Prior to that, she worked for the Greater Omaha Chamber of Commerce and served in the U.S. Congress for former Congressman Bill Barrett and former Congresswoman Virginia Smith, both of whom represented the 3rd Congressional District of Nebraska. Ms. Wightman serves on the board of directors for the Nebraska Chamber of Commerce, Rose Theater for Performing Arts, and Joslyn Castle. NioCorp Critical Mineral Security Board of Directors (slide 2 of 2) Peter Oliver 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, a mining company, where he served as General Manager of Talison's Greenbushes and Wodgina Mines and as Talison's Chief Operating Officer, 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 Australian Stock Exchange in September 2010. Mr. Oliver guided Talison through its acquisition in 2013 by Tianqi Lithium Corporation. 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 Albermarle 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. Dean C. Kehler Mr. Kehler is Managing Partner of Trimaran, which he co-founded in 1998, and serves as a Manager of Trimaran Fund II. Prior to Trimaran, Mr. Kehler was a Managing Director and Vice Chairman of CIBC, where he was responsible for CIBC's United States and European Merchant Banking activities, which were conducted through the CIBC Funds. In addition, Mr. Kehler was responsible for overseeing CIBC's United States and European Leveraged Finance businesses, which included financial sponsor coverage; acquisition finance; high yield origination, underwriting, sales and trading; private placements; and financial restructuring advisory services. Prior to CIBC, Mr. Kehler was a co- founder of The Argosy Group LP. Prior to Argosy, Mr. Kehler was a Managing Director of Drexel Burnham Lambert Inc., and before that he was an investment banker at Lehman Brothers. Mr. Kehler serves on the Boards of Directors of Celularity, Inc. (biotech; NASDAQ: CELU); and Portman Ridge Finance Corp... (fixed income investments/asset management; NASDAQ: PTMN). Mr. Kehler previously served as a Director, Treasurer and Chair of the Finance Committee of CARE USA, one of the world's largest private humanitarian organizations; and as Chair of the Board of Overseers of the University of Pennsylvania School of Nursing. Mr. Kehler graduated from the Wharton School of the University of Pennsylvania. Michael G. Maselli Mr. Maselli is a Managing Director of Trimaran Fund Management, L.L.C. since 2006. Most recently, he served as President of GXII (NASDAQ: GXII). Mr. Maselli has guided companies and their boards as a director or advisor for over 30 years. Before joining Trimaran, Mr. Maselli worked in the Corporate and Leverage Finance Groups of CIBC. 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. Since, 2011, Mr. Maselli has served as the Chairman of the Board of El Pollo Loco Holdings Inc. (NASDAQ: LOCO). From 2013 to 2015, he served on the board of directors of Norcraft Companies, Inc., and served on the board of managers of its predecessor company beginning in 2003. Additionally, Mr. Maselli served on the board of directors of ChanceLight, Inc. (f/k/a Educational Services of America, Inc.) and 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. 37#38Low Carbon Economy Defense and Aerospace Mega- Infrastructure NioCorp Critical Mineral Security Investment Highlights Potential pure play exposure to critical mineral mega trends¹ Significant, rapidly growing total available markets Unique competitive position with large barriers to entry Key customer relationships and offtake agreements Government permits in hand for construction start Attractive valuation 1 Subject to receipt of necessary project financing and commencement of operations at the Elk Creek Project. 38#39Nio Critical Mineral Security APPENDIX 39#40Elk Creek Project Advancement: Next Steps¹ Various levels of funding can advance the project to create additional value and move the project closer to the commencement of mine and surface construction.² Examples of Uses of Funds at Various Levels (USD millions) (for illustrative purposes only) Cost Element Final Subsurface Water and Subsoil Characterization Exercise Additional Land Options Final Engineering Before Construction Start Site Preparation and Infrastructure Initial Construction Works Production and Ventilation Shafts Overhead and Site Management Costs Contingency G&A / NioCorp Execution Team NioCorp Critical Mineral Security Uses of Funds at Various Levels (USD millions) $25 $100 $150 $300 $11 $11 $11 $11 $4 $4 $9 $9 $2 $22 $39 $39 $40 $40 $40 $15 $15 $94 $49 $21 $22 I I I $3 $1 $3 $14 $3 $5 $19 $11 $7 1 Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 Total Elk Creek Project up-front capital expenditure of $1.141 billion. 40#411970: Discovery of a gravity anomaly during an airborne gravity geophysical survey by State of Neb. HH ~500 million years ago: carbonatite genesis. ~200 million years ago: Limestone cap formed over carbonatite. 1971: Initial exploratory hole drilled 1973: Molycorp starts exploration after assembling a land package (NN-1), discovering carbonatite NioCorp Critical Mineral Security Progression to a Highly De-Risked Critical Minerals Project 1986: Molycorp halts exploration and calculates an initial resource; Elk Creek Project not advanced due to Molycorp's interest in other projects 1978: Molycorp discovers Niobium resource 2012: First NI 43-101 compliant resource report 2009: NioCorp assembles land package and resumes exploration 2014: ThyssenKrupp Metallurgical contracts for 50% of planned FeNb production over first 10 years 2014/2015: Additional resource, geotechnical, hydrogeology drilling and site investigations 2018: Traxys N.A. contracts for up to 12 tonnes/ year of planned Scandium production over first 10 years 2016: CMC Cometals contracts for 25% of planned FeNb production over first 10 years² 2021: NioCorp acquires key land parcel and mineral rights to 90%+ of Mineral Resource & Reserve 2017/2019/ 2022: Feasibility Studies published 2022: NioCorp issues updated NI 43-101- compliant technical report and filed first S-K 1300-compliant technical report summary based on June 2022 Feasibility Study 2022: NioCorp launches demonstration plant to optimize processing and measure rare earth recoveries 2024: NioCorp expects to issue updated Feasibility Study incorporating rare earth economics Nb,0, (%) L The Elk Creek Resource¹ Indicated Total drilling: 68,334 meters (42 miles) • Resource dimensions: 830 meters strike, 500 meters wide, 850 meters dip Inferred • Majority (~90%) of resource is under NioCorp-owned property; the remainder is under optioned property to the West 1 Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 Contract subsequently assigned by CMC Cometals to Traxys Cometals USA, LLC. • Potential expansion of the deposit to the NW, to the SE, at depth, and in the center. 41#42Classification Elk Creek 2022 In Situ Mineral Resource Estimate (niobium, titanium, and scandium) excluding reserves Indicated Inferred NSR Cutoff (US$/tonne) NioCorp Critical Mineral Security 180 180 Elk Creek S-K 1300 Mineral Resource¹ Tonnage (Mt) 151.7 108.3 (MINERAL RESOURCE AS OF June 30, 2022) Grades Nb205 (%) 0.43 TiO2 (%) 2.02 Sc (ppm) 56.42 Nb205 (%) 0.39 TiO2 (%) 1.92 Sc (ppm) 52.28 Tonnages Nb205 (kt) 649.8 TiO2 (kt) 3,067 Sc (t) 8,558 Nb205 (kt) 426.6 TiO2 (kt) 2,082 Sc (t) 5,660 NOTE: The Qualified Person for the Mineral Resource estimate is Understood Mineral Resources Ltd. The estimate has an effective date of June 30, 2022. Notes: a. Classification of Mineral Resources in the above tables is in accordance with the S-K 1300 classification system. Mineral Resources in this table are reported exclusive of Mineral Reserves b. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. The Mineral Resources are reported at a Diluted Net Smelter Return (NSR) Cut-off of US $180/tonne. The diluted NSR is defined as: C. d. e. f. g. h. i. j. . ● Diluted NSR (U.S. $) = Revenue per block Nb₂05 (diluted) + Revenue per block Tio2 (diluted) + Revenue per block Sc (diluted) Diluted tonnes per block The diluted revenue from Nb₂O5, TiO2, and Sc per block used the following factors: • Nb₂O5 Revenue: a 94% grade recovery, 0.696 factor to convert Nb₂O5 to Nb, 82.36% assumption for plant recovery, and a US$ 39.60 selling price per kg of ferroniobium as of June 30, 2022. • TiO₂ Revenue: a 94% grade recovery, a 40.31% assumption for plant recovery, and a US$ 0.88 selling price per kg of titanium oxide as of June 30, 2022. Sc Revenue: a 94% grade recovery, a 1.534 factor to convert Sc to SC₂O3, 93.14% assumption for plant recovery, and a US$ 3,675 kg selling price per kg of scandium oxide as of June 30, 2022. The diluted tonnes are a 6% increase in the total tonnes of the block. Price assumptions for FeNb, Sc₂O3, and TiO₂ are based upon independent market analyses for each product. Numbers may not sum due to rounding. The rounding is not considered to be material. Rare Earth Oxides (REO) were evaluated as a potential by-product to the mining of niobium, titanium, and scandium; thus the estimated values of the REOs are reported using the previously determined diluted NSR as derived from the Nb₂O5, TiO₂, and Sc Mineral Resources and are assigned a price of $0. The stated Light Rare Earth Oxides (LREO) grade (%) is the summation of La₂O3 (%), Ce₂O3 (%), Pr₂O3 (%), and Nd₂O3 (%) estimates. The stated Heavy Rare Earth Oxides (HREO) grade (%) is the summation of Sm₂O3 (%), Eu203 (%), Gd₂03 (%), Tb₂O3 (%) , Dy2O3 (%), Ho₂O3 (%), Er₂O3 (%), Tm₂03 (%), Yb₂O3 (%), Lu₂03 (%), and Y₂O3 (%) estimates. The stated Total Rare Earth Oxide (TREO) grade (%) is the summation of LREO (%) and HREO (%). Based on the S-K 1300 Elk Creek Technical Report Summary. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 42#43Class Indicated Class Inferred Elk Creek 2022 In Situ Mineral Resource Estimate (rare earth oxides) excluding reserves Tonnage (Mt) La203 (kt) La203 (%) 0.0766 Nd₂03 (%) 0.0511 Gd203 (%) 0.0096 Ho203 (%) 0.0006 Yb203 (%) 0.0010 LREO (%) 0.2737 116.2 Nd₂O3 (kt) 77.5 Gd203 (kt) 14.6 Ho203 (kt) 1.0 Yb203 (kt) 1.5 LREO (kt) 415.2 Ce203 (%) 0.1320 Sm₂03 (%) 0.0116 Tb203 (%) 0.0011 Er203 (%) 0.0015 Lu203 (%) 0.0001 HREO (%) 0.0528 NSR Cut-off 180 NSR Cut-off 180 151.7 NioCorp Critical Mineral Security Tonnage (Mt) 108.3 Elk Creek S-K 1300 REE Mineral Resource¹ (MINERAL RESOURCE AS OF JUNE 30, 2022) La203 (%) 0.0943 Nd₂03 (%) 0.0575 Gd203 (%) 0.0090 Ho203 (%) 0.0006 Yb203 (%) 0.0010 LREO (%) 0.3257 La203 (kt) 102.1 Nd₂O3 (kt) 62.2 Gd203 (kt) 9.8 Ho203 (kt) 0.7 Yb203 (kt) 1.1 LREO (kt) 352.6 Ce203 (%) 0.1576 Sm₂03 (%) 0.0116 Tb203 (%) 0.0010 Er203 (%) 0.0014 Lu203 (%) 0.0001 HREO (%) 0.0512 Ce203 (kt) 200.2 Sm₂03 (kt) 17.6 Tb203 (kt) 1.6 Er203 (kt) 2.2 Lu203 (kt) 0.2 HREO (kt) 80.0 Ce203 (kt) 170.6 Sm₂O3 (kt) 12.6 Tb203 (kt) 1.1 Er203 (kt) 1.5 Lu203 (kt) 0.1 HREO (kt) 55.5 Pr203 (%) 0.0140 Eu₂O3 (%) 0.0040 Dy203 (%) 0.0044 Tm203(%) 0.0002 Y203 (%) 0.0187 TREO (%) 0.3265 Pr203 (%) 0.0163 Eu₂O3(%) 0.0038 Dy203 (%) 0.0042 Tm203(%) 0.0002 Y203 (%) 0.0182 TREO (%) 0.3769 Pr203 (kt) 21.3 Eu₂O3 (kt) 6.0 Dy203 (kt) 6.7 Tm203 (kt) 0.3 Y203 (kt) 28.4 TREO (kt) 495.2 Pr203 (kt) 17.7 Eu₂O3 (kt) 4.1 Dy203 (kt) 4.6 Tm203 (kt) 0.2 Y203 (kt) 19.7 TREO (kt) 408.1 NOTE: The Qualified Person for the Mineral Resource estimate is Understood Mineral Resources Ltd. The estimate has an effective date of June 30, 2022. Notes: a. b. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. C. The Mineral Resources are reported at a Diluted Net Smelter Return (NSR) Cut-off of US $180/tonne. d. The diluted NSR is defined as: f. g. h. i. Classification of Mineral Resources in the above tables is in accordance with the S-K 1300 classification system. Mineral Resources in this table are reported exclusive of Mineral Reserves j. • TiO₂ Revenue: a 94% grade recovery, a 40.31% assumption for plant recovery, and a US$ 0.88 selling price per kg of titanium oxide as of June 30, 2022. Sc Revenue: a 94% grade recovery, a 1.534 factor to convert Sc to Sc₂O3, 93.14% assumption for plant recovery, and a US$ 3,675 kg selling price per kg of scandium oxide as of June 30, 2022. The diluted tonnes are a 6% increase in the total tonnes of the block. e. Price assumptions for FeNb, Sc₂O3, and TiO₂ are based upon independent market analyses for each product. Numbers may not sum due to rounding. The rounding is not considered to be material. Rare Earth Oxides (REO) were evaluated as a potential by-product to mining of niobium, titanium, and scandium; thus the estimated values of the REOS are reported using the previously determined diluted NSR as derived from the Nb₂O5, TiO2, and Sc Mineral Resources and are assigned a price of $0. The stated Light Rare Earth Oxides (LREO) grade (%) is the summation of La₂O3 (%), Ce₂O3 (%), Pr₂O3 (%), and Nd₂O3 (%) estimates. The stated Heavy Rare Earth Oxides (HREO) grade (%) is the summation of Sm₂03 (%), Eu₂O3 (%), Gd₂O3 (%), Tb₂O3 (%) , Dy2O3 (%) , Ho₂O3 (%), Er₂O3 (%), Tm₂O3 (%), Yb₂O3 (%), Lu₂03 (%), and Y2O3 (%) estimates. The stated Total Rare Earth Oxide (TREO) grade (%) is the summation of LREO (%) and HREO (%) The effective date of the Mineral Resource, including by-products, is June 30, 2022 k. ● Diluted NSR (U.S. $) = Revenue per block Nb₂05 (diluted) + Revenue per block Tio2 (diluted) + Revenue per block Sc (diluted) Diluted tonnes per block The diluted revenue from Nb₂O5, TiO2, and Sc per block used the following factors: Nb₂O5 Revenue: a 94% grade recovery, a 0.696 factor to convert Nb₂O5 to Nb, 82.36% assumption for plant recovery, and a US$ 39.60 selling price per kg of ferroniobium as of June 30, 2022. ● Based on the S-K 1300 Elk Creek Technical Report Summary. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 43#44Classification Proven Probable ● TOTAL Tonnage (Kt) 36,656 36,656 Underground In Situ Mineral Reserves Estimate for Elk Creek TiO₂ Grade (%) Nb₂05 Grade (%) NioCorp Critical Mineral Security 0.81 0.81 Contained Nb₂05 (t) 297,278 297,278 Payable Nb (t) Elk Creek S-K 1300 Mineral Reserve¹ (not including REE production) (MINERAL RESERVE AS OF May 10, 2022) 170,409 2.92 170,409 2.92 Contained TiO₂ (t) 1,071,182 1,071,182 Payable TiO₂ (t) 431,793 431,793 Sc Grade (ppm) 70.2 70.2 Contained Sc Payable (t) SC₂O3 (t) 2,573 2,573 3,677 NOTES The Qualified Person for the Mineral Reserve estimate is Richard Jundis, P.Eng., of Optimize Group Inc. The estimate has an effective date of May 3rd, 2022. The Mineral Reserve is based on the mine design and mine plan, utilizing an average cut-off grade of 0.679% Nb205 with an NSR of US$ 180/mt. 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. 3,677 The economic assumptions used to define Mineral Reserve cut-off grade are as follows: o Annual life of mine (LOM) average production rate of ~7,450 tonnes of FeNb/annum in the years of full production, 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. O Mining recoveries of 95% were applied in longhole stopes and 62.5% in sill pillar stopes. Parameter Mining Cost Processing Water Management and Infrastructure Tailings Management Other Infrastructure General and Administrative Royalties/Annual Bond Premium Other Costs Total Cost Nb₂O5 to Niobium conversion. Niobium Process Recovery Niobium Price TiO₂ Process Recovery TiO₂ Price Sc Process Recovery Sc to Sc₂O3 conversion Value 42.38 106.70 16.62 2.01 5.47 8.91 8.34 6.29 Unit US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined 196.72 69.60 82.36 39.60 US$/kg 40.31 % 0.88 93.14 153.40 % % US$/kg % % Price assumptions for FeNb, Sc203, and TiO2 are based upon independent market analyses for each product. Price and cost assumptions are based on the pricing of products at the "mine-gate," with no additional down-stream costs required. The assumed products are a ferroniobium product (metallic alloy shots consisting of 65% Nb and 35% Fe), a titanium dioxide product in powder form, and scandium trioxide in powder form. The Mineral Reserve has an average LOM NSR of US$ 563.06/tonne. Richard Jundis has provided detailed estimates of the expected costs based on the knowledge of the style of mining (underground) and potential processing methods (by 3rd party Qualified Persons). Mineral reserve effective date May 10th, 2022. The financial model was run post-February 2019, which reflects a total cost per tonne of US$ 196.72 versus US$ 189.91 (May 20, 2022 Mineral Reserve Details Table above). This is not considered a material change. Price variances for commodities are based on updated independent market studies versus earlier projected pricing. The updated independent market studies do not have a negative effect on the reserve. ¹ Based on the 2022 Elk Creek Technical Report. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 44#45Classification ● Proven Probable ● TOTAL Underground In Situ Mineral Reserves Estimate for Elk Creek Payable TiO₂ Nb Grade (t) (%) Tonnage (Kt) O Nb₂05 Grade (%) NioCorp Critical Mineral Security 36.656 0.81 36,656 0.81 Contained Nb₂O5 (t) Elk Creek S-K 1300 Mineral Reserve¹ (not including REE production) (MINERAL RESERVE AS OF June 30, 2022) 297,278 170,409 2.92 297,278 170,409 2.92 Contained TiO₂ (t) 1,071,182 1.071.182 Payable TiO₂ (t) 431,793 Sc Grade (ppm) 70.2 431,793 70.2 Contained Payable Sc (t) Sc₂03 (t) 2,573 NOTES The Qualified Person for the Mineral Reserve estimate is Optimize Group Inc. The estimate has an effective date of June 30, 2022. The Mineral Reserve is based on the mine design, mine plan, and cash-flow model utilizing an average cut-off grade of 0.679% Nb₂O5 with an NSR of US$ 180/t. 2.573 3.677 3,677 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 economic assumptions used to define Mineral Reserve cut-off grade are as follows: O Annual life of mine (LOM) production rate of ~7,450 tonnes of FeNb/annum during the years of full production. O Initial elevated five-year production rate ~ 7,500 tonnes of FeNb/annum when full production is reached. O 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. Mining recoveries of 95% were applied in longhole stopes and 62.5% in sill pillar stopes. Parameter Mining Cost Processing Water Management and Infrastructure. Tailings Management Other Infrastructure General and Administrative Royalties/Annual Bond Premium Other Costs Total Cost Nb₂O5 to Niobium conversion Niobium Process Recovery Niobium Price TiO₂ Process Recovery TiO₂ Price Sc Process Recovery Sc to Sc₂O3 conversion Sc Price Value 42.38 106.70 16.62 2.01 5.47 8.91 8.34 6.29 196.72 69.60 82.36 39.60 40.31 0.88 93.14 153.40 3,675.00 Unit US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined US$/t mined % % US$/kg % US$/kg % % US$/kg Price assumptions are as follows: FeNb US$ 39.60/kg Nb, Sc₂O3 US $3,675/kg, and TiO₂ US $0.88/kg. Price assumptions are based upon independent market analyses for each product as of June 30, 2022 Price and cost assumptions are based on the pricing of products at the "mine-gate," with no additional down-stream costs required. The assumed products are ferroniobium (metallic alloy shots consisting of 65% Nb and 35% Fe), a titanium dioxide product in powder form, and scandium trioxide in powder form. The Mineral Reserve has an average LOM NSR of US$ 563.06/tonne. Optimize Group has provided detailed estimates of the expected costs based on the knowledge of the style of mining (underground) and potential processing methods (by 3rd party Qualified Persons). Mineral reserve effective date is June 30, 2022. The financial model was run after the estimate of the NSR above, which reflects a total cost per tonne of US$ 196.72 versus US$ 189.91. This is not considered a material change. Price variances for commodities are based on independent market studies versus earlier projected pricing. The independent market studies do not have a negative effect on the reserve. 1 Based on the S-K 1300 Elk Creek Technical Report Summary. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 45#46Operating Year Production Niobium Scandium Titanium Realized Pricing Niobium Scandium Titanium Gross Revenues ($M) Total Opex ($M) EBITDA ($M) 2 EBITDA Margin 2 Operating CF ($M) ² EBT ($M)² Net Income ($M) Income Margin NioCorp Critical Mineral Security t-Nb t-Sc₂O3 t-TiO₂ $/kg $/kg $/kg 1 4,960 116 13,063 $3,986 $0.99 $701 ($205) $496 71% $496 $227 $227 32% Feasibility Study: Indicated Economic Results¹ 2 4,742 114 12,120 $3,487 $0.99 $626 ($200) $426 68% $426 $202 $202 32% 3 4,949 113 12,747 5.46 $2,989 $0.99 $575 ($201) $374 65% $353 $181 $161 28% 4 4,903 109 12,605 $45.46 $3,088 $0.99 $573 ($207) $366 64% $328 $188 $150 26% 5 4,949 112 12,606 5.46 $3,188 $0.99 $596 ($210) $386 65% $341 $222 $176 30% 6 4,716 109 12,114 .46 $3,387 $0.99 $594 ($196) $398 67% $346 $259 $207 35% 7 4,715 105 11,846 $3,586 $0.99 $602 ($201) $401 67% $342 $284 $225 37% 8 4,733 102 12,167 $608 $45.46 $3,735 $3,734 $0.99 $0.99 ($202) 9 $406 67% $345 $295 $234 39% 4,799 101 11,926 $608 ($210) $398 65% $339 $287 $228 38% 10 4,672 101 11,544 $45.84 $3,750 $0.99 $606 ($211) $395 65% $339 $283 $226 37% 20 4,772 102 12,365 $47 $3,750 $0.99 $617 ($207) $411 67% $339 $293 $221 36% 1 Based on Table 19-12 "Indicative Economic Results" from the S-K 1300 Elk Creek Technical Report Summary. See "Mineral Reserves and Resources" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 2 See "Financial Information; Non-GAAP Measures" in the Disclaimers & Technical Disclosures at the beginning of this presentation. 30 4,773 107 12,527 $47.00 $3,750 $0.99 $637 ($200) $436 69% $356 $326 $245 39% 46#47For More Information NioCorp Jim Sims Chief Communications Officer [email protected] +1 (303) 503-6203 NioCorp Critical Mineral Security CONTACT 47