The leaching phase of the feasibility field test began in September 2022 and the company said the preliminary results received to date have demonstrated the successful acidification of a test pattern and recovery of uranium through ISR. Several samples of recovered solution have been collected during the leaching phase and remain subject to full lab assay and analysis, which will generate additional detailed information about the performance of the feasibility field test.

“The recovery of uranium bearing solution at targeted rates and grades is history in the making,” said Kevin Himbeault, vice president of plant operations and regulatory affairs for Denison. “Initial analysis indicates the hydrogeological system has responded as expected with pH trends, flow characteristics and uranium recovery meeting expectations.”

Given the highly successful results of the feasibility field test, Denison said it has ceased lixiviant injection, and operators at the Phoenix FFT site are preparing to transition from the leaching phase of the feasibility field test to the neutralization phase, which is expected to be completed before the end of the year. The final phase of the feasibility field test, which involves management of the recovered solution, is expected to begin in the spring of 2023.

The leaching phase was designed to assess the effectiveness and efficiency of the leaching process in the mineralized zone, which is approximately 400 m below the surface. The leaching phase includes the controlled injection of an acidic solution into a portion of the existing test pattern within the mineralized zone and the recovery of the solution back to the surface using existing test wells.

The neutralization phase involves the recovery of the remainder of the leached mineralized solution from the leaching zone and is intended to verify the efficiency and effectiveness of the process for returning the leaching zone to environmentally acceptable conditions. During this phase, a mild alkaline (basic) solution will be injected into the leaching zone to neutralize the area and reverse the residual effects of the acidic solution injected during the leaching phase.