Denison resumes ISL work at Phoenix

28 July 2020

Denison Mines has resumed in situ leach (ISL) field testing activities at the high-grade Phoenix deposit at Wheeler River in northern Saskatchewan, Canada. All operating procedures have been adapted to incorporate physical distancing and enhanced hygiene protocols to comply with COVID-19 health and safety guidelines.

Exploration camp at Wheeler River (Image: Denison)

The field tests were included in Denison's operating plan for the year which was announced in March and aims to further evaluate and de-risk ISL mining conditions at Phoenix, supplementing findings from the 2019 field programme. Data from last year's field testing enabled the development of a hydrogeologic model and simulation of an ISL wellfield for Phoenix and ultimately demonstrated 'proof of concept' for the use of the technique at the site.

Denison President and CEO David Cates said the company has over recent months developed extensive health and safety protocols and procedures to ensure a return to site work can be achieved safely for staff, contractors and the northern communities personnel must pass through to reach Wheeler River. "With the continuation of [ISL] field testing at Phoenix in 2020 we hope to minimise the impact of COVID-19 related disruptions to the overall project development schedule and environmental assessment process," he said.

The protocols developed by Denison consider the unique health and safety risks associated with operating a remote work camp amidst the ongoing pandemic, the company said. Special protocols to minimise health and safety risks associated with travel to and from the site through various communities in northern Saskatchewan have been developed in consultation with community leaders. However, it remains possible that the 2020 programme may be affected by the "continuously evolving social and/or economic disruptions" associated with COVID-19 which are outside its control, the company said.

Denison describes Wheeler River - with combined indicated mineral resources of 132.1 million pounds U3O8 (50,812 tU) plus combined inferred resources of 3.0 million pounds U3O8 - as the largest undeveloped uranium project in the infrastructure rich eastern portion of the Athabasca Basin region. The project is host to the high-grade Phoenix and Gryphon uranium deposits, and is a joint venture between Denison (90% and operator) and JCU (Canada) Exploration Company Limited (10%).

Denison began the environmental impact assessment process for Wheeler River in June 2019 but temporarily suspended related activities in March this year in response to COVID-19.

ISL - also known as in-situ recovery or ISR - involves pumping a solution through an orebody to dissolve the uranium-bearing mineral and pumping the resulting solution to the surface where the uranium can be recovered. This means there is little surface disturbance and no tailings or waste rock generated, but the method is only applicable to geologically suitable deposits. According to World Nuclear Association, around half of the world's uranium is now produced using ISL mining methods. The technique has not as yet been used for uranium production in Canada. The Gryphon deposit is not suitable for recovery by this technique.

Researched and written by World Nuclear News