Wheeler River - Gryphon

Gryphon is a basement-hosted unconformity-associated uranium deposit on the Wheeler River project, located ~3 km northwest of the Phoenix deposit. Discovered by Denison in 2014, it occurs 520-850 m below surface within southeasterly-dipping crystalline basement rocks of the Wollaston Supergroup, comprising 24 stacked A/B/C/D/E lenses over 610 m strike × 390 m dip. Planned conventional longhole stoping with backfill, accessed via two blind-bored shafts, with ore trucked to the McClean Lake mill for processing. Gryphon PFS Update (Wheeler Report, June 23, 2023): 49.7 Mlb U3O8 Probable reserves (1.257 Mt @ 1.8%), 9 Mlb/yr peak production with 2-yr ramp-up, mine life supports parallel processing alongside Cigar Lake Phase 2. Estimated initial capex $737.4M (AACE Class 4, Q3 2022 CAD), sustaining $98.7M, LOM operating cost $843.2M ($17.27/lb; US$12.75/lb). Pre-tax NPV8% $1.43B (100%), after-tax NPV8% $864.2M (100%, Denison share $821.0M), IRR 37.6%, 22-month after-tax payback. In 2025 Denison completed ~12,500 m delineation drilling (17 holes plus off-cuts) confirming continuity and supporting feasibility-study advancement; metallurgical testwork ongoing. Pre-commitment costs of $56.5M required before Construction Licence / FID.