Peninsula Energy Has Been Authorized By Wyoming To Use Acidic Solutions For In Situ Mining Of Uranium At The Lance Mine
In situ leaching is a mining technique for extracting minerals such as copper and uranium. Holes are drilled into the ore deposit and leaching fluid is pumped into the holes. The solution carrying the dissolved ore is then pumped back to the surface and processed. In uranium in situ mining, an acidic solution such as sulfuric acid or an alkaline solution such as sodium bicarbonate is used. In situ mining does little to disturb the landscape and there are no mine tailings or waste rock created.
The ore body must be permeable to the leaching solution. In addition, care must be taken that the leaching solution will not reach the ground water in the area of the mine. The choice of acidic or alkaline leaching solution depends on the geology of the ore body. In general, leaching with an acidic solution recovers more uranium and costs less than alkaline leaching.
The in-situ process is used around the world to extract forty five percent of the uranium mined. In situ mining of uranium started in the U.S. and Soviet Union in the early 1960s using sulfuric acid. Since 1970, all commercial in-situ uranium mines in the U.S. have used carbonate solutions which are alkaline.
Peninsula Energy Ltd has just finished the regulatory application process for the use of low pH in situ uranium mining at the Lance uranium project in Wyoming. Peninsula is now the only operator licensed to use low pH uranium extraction in the U.S. Low pH means that the leaching solution is acidic.
The Wyoming Department of Environmental Quality (WDEQ) formally approved an amendment to the Lance source materials license on 31 July. The WDEQ notified the Peninsula Energy Ltd subsidiary Strata Energy Inc the following day. The authorization confirmed that the acidic in situ leaching technology to be employed by Peninsula complies with the regulatory standards and requirements of the state regulator.
Wayne Heli is the CEO of Peninsula. He described the low pH recovery technique as a “proven and effective” method. Low pH recovery is in wide use in other parts of the world. Peninsula began working on authorization for their low pH in situ mining method in 2017. Tests had shown that using acidic rather than alkaline leaching solutions could possibly improve performance and reduce costs in uranium mining. Heli said, “The final implementation of this initiative is anticipated to bring significant benefit for our shareholders.”
Peninsula reduced uranium production at the Lance mine in the second quarter of 2019 to prepare for a transition from alkaline to acidic leaching. According to the amended Permit to Mine from the state regulatory authority, Peninsula must demonstrate the process before they can begin commercial operations. Peninsula said that actual commercial use of the acidic in situ mining at the Lance mine would be determined by “the timing and extent of improvement in the uranium market conditions and the companies' requirements for produced uranium.” Currently, there are four in-situ mining operations in the U.S. including the Peninsula mine in Wyoming.