NioCorp Investor Presentation Deck

Mineral Cut-off Resource NSR Classification (US$/t) Indicated Inferred Mineral Resource and Reserves¹ 180 Mineral Reserve Classification Probable 180 Tonnage Gr (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) 31

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