The move comes as the uranium spot price reached US$50 a pound this month - for the first time since 2012 - amid supply cutbacks and a rush in physical purchases.

Denison now owns 95% of Wheeler River, which it describes as the largest undeveloped uranium project in the eastern Athabasca Basin. 

A 2018 prefeasibility study had considered both an ISR operation at Phoenix and conventional underground mining at the Gryphon deposit, outlining combined production of 109.4 million pounds U3O8 over 14 years.

Phoenix alone was estimated to have initial capex of C$322.5 million, a pre-tax NPV8 of $930.4 million and IRR of 43.4% on a 100% basis, with low average operating costs of US$3.33/lb.

Denison had paused the ISR environmental assessment process for much of last year due to COVID-19. 

President and CEO David Cates said de-risking to date had confirmed the technical viability of the project.

"Based on the results of field programs and metallurgical lab testing completed over the last three years, we are confident that the project is ready to advance into a full feasibility study," he said.

He said the new study would be based on an updated resource, set to include recent drilling results including 8.6m at 22% U3O8.

Denison shares (TSX: DML), which were trading about C56c a year ago, peaked at $2.29 earlier this month.

They lost 2.2% yesterday to close at $1.76, valuing it at $1.4 billion (US$1.1 billion).