Phoenix Feasibility Study 2023

Fully Permitted In-Situ Recovery Feasibility Field Test (FFT): Highly successful first-of-its-kind test in the Athabasca Basin (1, 2) Double Walled Pipe to Recharge Well Lenison CAUTION The Phoenix FFT was designed to validate and inform various Feasibility Study (FS) elements for use of In-Situ Recovery (ISR) mining, including production and remediation profiles, and is planned to occur in three phases. The first two phases supported 2023 Phoenix FS. Leaching Completed successful injection of acidic solution and recovery of uranium bearing solution using a portion of the test | pattern installed at Phoenix in 2021(3). Neutralization Completed successful injection of mild alkaline solution to reverse the leaching process and return test area to protective conditions(4). Recovered Solution Management Completed compliance phase to separate recovered solution into mineralized precipitates | (temporarily stored on site) and neutralized treated solution (injected into sub-surface)(5). Test Wells Injection Solution Preparation Module -2-Trailers Recovered Solution Management Modules Mineralized- Precipitate Storage -03 OWR-040 ww-041 Washcar/Dry Trailer -Containment Berms Tanker Pad Recovered Solution Surge Tank -Double Walled Transfer Piping Perimeter Fence 6-Outdoor Solution Storage Tanks Solution Storage Area Graded Footprint 10 20 30 40 50m Containment Berms PHOTO: Inside FFT coverall structure during commissioning - including view of commercial scale test wells, monitoring wells, and injection solution preparation module (left) and plan map of Phoenix FFT site (right). NOTES: (1) See Denison's news release dated July 12, 2022. (2) See Denison's news release dated August 8, 2022. (3) See Denison's news release dated October 17, 2022. (4) See Denison's news release dated December 12, 2022. (5) See Denison's news release dated November 2, 2023. 14

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