Denison Mines Corp. announce the successful completion of the recovered solution management phase of the Phoenix in-situ recovery ('ISR') Feasibility Field Test ('FFT') at the Company's 95% owned Wheeler River project ('Wheeler River' or the 'Project'). View PDF version The FFT was highlighted by the recovery of 14,400 lbs U(3) O(8) dissolved in solution generated during the leaching and neutralization phases of the FFT in late 2022. The solution recovered during the operation of these phases was stored on site in accordance with permit conditions and in anticipation of the recovered solution management phase of the FFT. This phase was initiated during the first half of 2023 and involves the treatment of the recovered solution via an on-site purpose-built treatment system. Following treatment, a uranium bearing mineralized precipitate and a treated effluent were produced. The treated effluent was tested to ensure compliance with permit conditions before being injected into a designated subsurface area. The mineralized precipitates have been recovered from the process and are safely stored on surface in accordance with permit conditions. Completion of the Recovered Solution Management Phase The recovered solution management phase of the FFT commenced in April 2023 with the set-up and commissioning of the solids management and water treatment circuit. Approximately 560 m(3) of covered solution plus wash water used for cleaning of storage tanks and site equipment were processed during the operation of the treatment circuit. Treatment of
recovered solutions concluded in October 2023, resulting in the safe and successful treatment of all recovered solution, which ensured compliance with all provincial permit conditions. The approximately 14,400 lbs U(3) O(8) estimated to be contained within the recovered solution from the leaching and
neutralization phases were precipitated during the recovered solution management phase with over 99.99% efficiency, further validating the Company's processing designs and assumptions for the future Phoenix processing plant. The treated effluent injected into the subsurface during the recovered solution management phase was monitored for injection pressure and contained to the designated injection area, with no migration of the treated effluent observed above, below or outside of the injection area. Decommissioning of the Feasibility Field Test Site With the completion of the recovered solution management phase, Denison has initiated decommissioning of the FFT facilities, in accordance with its permit conditions. Decommissioning involves the cleaning, deconstruction, and shipment of equipment used during the leaching, neutralization, and solution management phases. Given the expected onset of winter weather conditions, Denison expects to complete the majority of the decommissioning of the FFT in 2024. Northern Indigenous Employment and Business Contributions Denison is also pleased to recognize the significant contributions of several members of the English River First Nation ('ERFN') and various Indigenous owned businesses to the successful completion of all the phases of the FFT in 2022 and 2023. Tron Construction & Mining, a well-established operator in northern Saskatchewan that is part of the Des Nedhe Group and owned 100% by ERFN, and PBN Construction, a Northern Saskatchewan Indigenous owned and operated contractor, provided qualified support for commissioning, maintenance, and decommissioning work throughout the various phases of the FFT. Feasibility Field Test Background The FFT was designed to use the commercial-scale ISR test pattern, installed at the Phoenix deposit in 2021, to facilitate a combined assessment of the deposit's hydraulic flow properties and its leaching characteristics previously determined through the metallurgical core-leach testing program. The operation of the FFT occurred in three phases: (1) the leaching phase, (2) the neutralization phase, and (3) the recovered solution management phase. The FFT is fully permitted, having been authorized by both the Saskatchewan Minister of Environment and the Canadian Nuclear Safety Commission. Overall, the FFT provided further verification of the permeability, leachability, and containment parameters needed for the successful application of the ISR mining method at Phoenix and validates and informs various design elements -- including the expected production and remediation profiles reflected in the results announced from the Feasibility Study for Phoenix during the summer of 2023.