Denison Mines to Break Ground on Phoenix Uranium Mine in March 2026

• Denison's board of directors formally approved a Final Investment Decision (FID) for the Phoenix uranium mine in February 2026, with site preparation and construction scheduled to begin in March 2026.
• Phoenix will use in-situ recovery (ISR), a method that extracts uranium by injecting a solution underground to dissolve the ore, then pumping the uranium-bearing liquid to the surface for processing, without conventional open-pit or underground excavation.
• All regulatory approvals are in place, including a provincial environmental assessment approval from Saskatchewan in July 2025 and a federal construction licence from the Canadian Nuclear Safety Commission in February 2026.
• Financing for the project has been secured ahead of the construction start.
• Denison is targeting first uranium production from Phoenix by mid-2028.

Denison Mines Corp. (TSX: DML / NYSE American: DNN) is a Toronto-based uranium exploration and development company focused on the Athabasca Basin region of northern Saskatchewan, Canada. The company holds an effective 95% interest in its flagship Wheeler River Project, which hosts the high-grade Phoenix and Gryphon uranium deposits. Denison also holds a 22.5% stake in the McClean Lake joint venture, which includes a share of the McClean Lake uranium processing mill currently operating under a toll milling arrangement, as well as interests in the Midwest joint venture and the Waterbury Lake property, with combined land holdings of approximately 457,000 hectares across the basin. Through its 50% ownership of JCU (Canada) Exploration Company Limited, the company holds further interests in several uranium joint ventures across Canada. Denison has been active in uranium mining, exploration, and development since 1954.

Final Investment Decision Approved and Construction Commencement Planned for March 2026

On 24 February 2026, Denison's board of directors approved the construction of the Phoenix ISR uranium mine, located within the Wheeler River Project in northern Saskatchewan. An FID is the formal, binding commitment of capital to build a mine, taken after a project has satisfied engineering, permitting, and financing requirements. Denison holds a 90% operating interest in the Wheeler River Project, with the remaining 10% held by JCU (Canada) Exploration Company Limited.

In the lead-up to the decision, Denison completed a feasibility study, procured long-lead equipment and materials, and awarded a construction management contract to Wood Canada. Grid power was also made available at the future mine site following the completion of a SaskPower transmission line, removing a key infrastructure dependency ahead of construction.

President and CEO David Cates stated:

"Making a Final Investment Decision and the upcoming initiation of construction activities at Phoenix mark the beginning of a new era in Denison's history and the Canadian uranium mining sector. Our teams have worked diligently over the last several years to bring Phoenix to a construction-ready state, obtain provincial and federal approvals, procure long-lead materials, and secure financing to be in a position to make this landmark decision."

Two-Year Construction Timeline Targeting First Production by Mid-2028

Construction of the Phoenix mine is expected to take approximately two years from the March 2026 start date, with first uranium production targeted by mid-2028. The ISR method selected for Phoenix involves extracting uranium without conventional underground or open-pit excavation, and the Wheeler River Project's feasibility study indicates that both the Phoenix and Gryphon deposits have the potential to be competitive with the lowest-cost uranium mining operations in the world.

Permitting efforts for the Phoenix ISR operation began in 2019, with approvals obtained at both the provincial and federal levels ahead of the FID. The completion of detailed design engineering, the procurement of long-lead materials, and the engagement of a construction management contractor were all completed prior to the board's decision, supporting the planned March 2026 construction start.

President and CEO David Cates noted:

"With construction anticipated to take approximately two years, commencing construction in March is expected to allow us to maintain our objective to achieve first production from Phoenix by mid-2028 and ultimately position Denison as one of the few uranium suppliers globally who will be able to provide a sizeable new source of uranium production before the end of the decade."

Phoenix to Become the First New Large-Scale Canadian Uranium Mine in Over Two Decades, with All Regulatory Approvals and Financing Secured

Phoenix is expected to be the first new large-scale uranium mine in Canada in more than 20 years. Regulatory approvals were obtained at both levels of government prior to the FID. Saskatchewan granted environmental assessment approval in July 2025, and the Canadian Nuclear Safety Commission issued its environmental assessment approval along with a Licence to Prepare Site and Construct in February 2026. Permitting efforts had commenced in 2019.

On the financing side, Denison closed a US$345 million convertible senior notes offering in 2025, providing the capital required to fund construction. With regulatory approvals, procurement, a construction management partner, and financing all in place at the time of the FID, Denison proceeded to the construction decision with the key project requirements addressed.

Wheeler River is described by Denison as the largest undeveloped uranium project in the infrastructure-rich eastern portion of the Athabasca Basin. The Phoenix deposit was discovered by Denison in 2008, and the project has been the subject of extensive field testing, engineering studies, and regulatory review in the years since.

Looking Ahead: Milestones and Next Steps

With the FID approved, Denison's immediate focus is site preparation and the commencement of construction activities in March 2026. The company's stated objective is to achieve first production from Phoenix by mid-2028. The Wheeler River Project also hosts the Gryphon deposit, which remains subject to a separate pre-feasibility study for conventional underground mining. Updates on construction progress, capital deployment, and production readiness are expected as the project advances through the two-year build period.

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