Denison Clears Final Federal Hurdle for Phoenix Uranium Mine, Paving the Way for Construction

• The Canadian Nuclear Safety Commission (CNSC) has approved the Environmental Assessment and issued a construction licence for the Phoenix ISR uranium mine at Wheeler River, completing all required regulatory approvals.
• Phoenix is the first uranium mine in Canada approved to use the In-Situ Recovery (ISR) mining method, a lower-footprint technique that extracts uranium without conventional excavation.
• This is the first large-scale uranium mine in Canada approved for construction in more than 20 years.
• With pre-construction licence conditions already addressed and a construction management contract recently awarded, Denison is positioned to begin site preparation immediately upon a final investment decision.
• Management is targeting first uranium production from Phoenix by mid-2028, based on an approximately two-year construction timeline.

Denison Mines Corp. (TSX: DML / NYSE American: DNN) is a Toronto-based uranium exploration and development company with interests focused in the Athabasca Basin region of northern Saskatchewan, Canada. The company holds a 90% operating interest in its flagship Wheeler River Project, a 22.5% stake in the McClean Lake Joint Venture, a 25.17% interest in the Midwest Joint Venture, and a 70.55% interest in the Tthe Heldeth Tue and Huskie deposits on the Waterbury Lake Property. Through its 50% ownership of JCU (Canada) Exploration Company, Limited, Denison also holds interests in several additional uranium project joint ventures across Canada. In total, Denison has direct ownership interests in properties covering approximately 457,000 hectares in the Athabasca Basin region and has been active in uranium mining, exploration, and development since 1954.

From Discovery to a Fully Permitted Mine: The Phoenix Story

The Phoenix deposit was discovered by Denison in 2008 within the Wheeler River Project in the eastern Athabasca Basin region of northern Saskatchewan. A second deposit, Gryphon, was discovered at the same project in 2014. Wheeler River is described by Denison as the largest undeveloped uranium project in the infrastructure-rich eastern portion of the Athabasca Basin. Based on the results of a feasibility study and pre-feasibility study filed in August 2023, both deposits have the potential to be competitive with the lowest-cost uranium mining operations in the world.

Phoenix has been designated for development using ISR mining, a method in which a liquid solution is injected underground to dissolve uranium in place, with the uranium-bearing solution then pumped to surface for processing. This approach does not require conventional rock excavation and is associated with a lower environmental footprint relative to traditional mining methods. Phoenix will be the first operation in Canada to use ISR mining at commercial scale.

The project is structured as a joint venture between Denison, which holds a 90% interest and serves as operator, and JCU (Canada) Exploration Company Limited, which holds the remaining 10%.

Regulatory Milestone: Seven Years in the Making

Denison initiated the environmental assessment process for Wheeler River in 2019. The regulatory review involved engagement with Indigenous and non-Indigenous communities, technical review by federal and provincial authorities, and a two-part public hearing held by the CNSC in October and December 2025. The Province of Saskatchewan approved the project's environmental assessment in July 2025. The CNSC's February 2026 decision to approve the federal environmental assessment and issue the construction licence completes all regulatory approvals required to commence construction.

President and CEO David Cates stated:

"The Commission decision to approve the EA and issue the Licence represents a landmark achievement for Denison, as well as our staff, shareholders, Indigenous partners, and other stakeholders in the Project. Phoenix is the first uranium mine in Canada to be approved for ISR mining and is the first large-scale Canadian uranium mine approved for construction in more than 20 years."

A draft licence presented during the October 2025 hearing proceedings included several conditions requiring resolution before site construction could begin. Denison addressed those conditions ahead of the licence being formally issued, meaning the company is in a position to proceed with site preparation and construction activities as soon as a final investment decision is confirmed.

Technical Groundwork Supporting Construction Readiness

In August 2023, Denison filed a technical report covering the results of the Phoenix Feasibility Study and an updated cost analysis for the Gryphon deposit. The feasibility study established the technical baseline for Phoenix's mine design, processing approach, capital requirements, and operating cost structure. Denison subsequently updated its initial capital cost estimate for Phoenix by press release on 2 January 2026.

In parallel with the regulatory process, Denison has advanced detailed engineering and awarded a construction management contract to Wood Canada. The company has also noted a strong financial position as a contributing factor to its readiness to proceed.

President and CEO David Cates noted:

"Given Phoenix's construction-ready state, our recent award of the construction management contract, and Denison's strong financial position, we are eager to conclude the Company's final investment decision for the Project and announce the timeline for the commencement of construction."

What Comes Next

With all regulatory approvals now in place, Denison's stated near-term priority is concluding a final investment decision for Phoenix. Once that decision is made, site clearing and construction activities are expected to commence. Based on an approximately two-year construction timeline, the company is targeting first production by mid-2028. Denison has indicated the project remains on track to meet that schedule.

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