Strata Energy Granted Non-Significant Revision to Allow Low-pH Field Test
OSHOTO, WY. The Wyoming Department of Environmental Quality (WDEQ) has approved a Non-Significant Revision (NSR) to Strata’s Permit to Mine to allow a small-scale Field Leach Trial (FLT) using low-pH lixiviant at the Ross Uranium Mine near Oshoto. The trial is expected to commence in December.
The approval marks the next step in WDEQ consideration of Strata’s request to amend its Permit to Mine to allow for the use of a low-pH solution in the recovery of uranium at Ross. The company’s existing permit authorizes the use of alkaline and oxidant solutions in the in-situ recovery (ISR) process. Those solutions are generated by mixing native groundwater with carbon dioxide and/or sodium bicarbonate and gaseous oxygen.
Since uranium recovery efforts commenced in December 2015, the ore deposit at Ross has proven only moderately amenable to these alkaline solutions. Despite improved production rates over the last year, the overall uranium recovery rates at Ross continue to be below targeted levels.
The proposed permit revision would allow use of low concentrations (1.5% or less) of sulfuric acid mixed with native groundwater.
Of the 77 million pounds of uranium produced by ISR methods worldwide in 2015, ninety-six percent (96%) or 74 million pounds came from facilities using low-pH lixiviants. A successful transition to low-pH operations could align the operating performance and cost profile of the Lance Projects with current industry leading global uranium production projects.
The approved NSR field trial is designed to provide field-scale confirmation of laboratory testing and geochemical modeling to demonstrate that low-pH methods can be used safely. as WDEQ considers the two regulatory actions necessary for full-scale commercial low-pH operations at Ross. The FLT will allow Strata to conduct testing of low-pH lixiviant on a very small scale. The trial will take place in seven wellfield patterns within previously mined areas of an existing wellfield. The wellfield patterns comprise just 1.78 acres, or 5.4% of the wellfield area.
In order to receive approval for the FLT, Strata was required to demonstrate that the trial will not interfere with approved plant or wellfield operations and will not compromise public health, worker safety and environmental requirements. The FLT areas are monitored by shallow, deep, and perimeter monitoring wells. These wells are monitored bimonthly to detect unwanted migration of mining solutions.
WDEQ evaluation of Strata’s requested amendment to the Permit to Mine is expected to extend well into 2019, and will include a robust technical and environmental evaluation, as well as opportunities for public input.
Strata will publish information on permitting milestones, public hearings and opportunities for public comment on the company website at www.stratawyo.com. Legal notices regarding public hearings and comment periods will be published in the Moorcroft Leader.