Denison Mines Approves Construction of Phoenix ISR Uranium Mine, Targets First Production by Mid-2028

• Denison's board approved the Final Investment Decision for the Phoenix ISR uranium mine in February 2026, with site preparation and construction scheduled to begin in March 2026.
• Total initial capital for Phoenix is estimated at approximately $600 million at a Class 2 precision level, with an approximately two-year construction timeline and first production targeted by mid-2028.
• US$345 million in convertible senior notes were raised in August 2025 at a 4.25% annual interest rate, maturing September 2031, to fund construction.
• The McClean North SABRE mine commenced production in July 2025 and produced 648,558 pounds of U3O8 on a 100% basis during the year at an average operating cost of approximately US$26 per pound.
• Denison signed an Impact Benefit Agreement with Métis Nation-Saskatchewan in December 2025, and a separate regional benefit agreement with the Ya'thi Néné Land and Resource Office, three First Nations groups, and four northern municipalities.

Denison Mines Corp. (TSX: DML | NYSE American: DNN) is a Canadian-based uranium mining, exploration and development company focused on the Athabasca Basin region of northern Saskatchewan. The company holds a 95% effective interest in its flagship Wheeler River Uranium Project, which contains the Phoenix and Gryphon uranium deposits, along with joint venture interests in the producing McClean Lake uranium mine and mill, the Midwest deposit, and the Waterbury Lake Property. In total, Denison's direct interests span approximately 457,000 hectares across the Athabasca Basin. The company has been engaged in uranium mining, exploration and development since 1954.

2025 Year-End Financial and Operational Results

Much of Denison's activity in 2025 centred on advancing Phoenix toward a construction-ready state. By year-end, approximately 87% of total engineering had been completed, with 92% of primary engineering deliverables already issued for construction. The company also executed key construction contracts and continued purchasing long-lead items, which are equipment and materials that carry extended delivery times and must be ordered well in advance of construction. In August 2025, Denison completed a US$345 million offering of convertible senior unsecured notes at a 4.25% annual interest rate, maturing September 2031, to fund the project.

On the production side, the McClean Lake Joint Venture commenced uranium mining at the McClean North deposit in July 2025 using the patented SABRE method, a surface-access technique that extracts high-grade ore through boreholes drilled from the surface without requiring underground excavation. Over the remainder of the year, 648,558 pounds of U3O8 were produced on a 100% basis, with Denison's share amounting to approximately 145,926 pounds at an average operating cost of about US$26 per pound. CEO David Cates described McClean North as one of the most productive operating uranium mines in North America.

A separate development covered in the 2025 results is the Midwest Preliminary Economic Assessment (PEA), which modelled the potential use of ISR mining at the Midwest Main deposit. The PEA outlined estimated total production of 37.4 million pounds of U3O8 over an approximately six-year mine life, with an after-tax base-case net present value of $965 million and an internal rate of return of 82.7%, at initial capital of $254 million. A PEA is a preliminary study that does not confirm economic viability, and there is no assurance the joint venture will advance development using the ISR method or that PEA results will be realised. Denison holds a 25.17% interest in the Midwest Joint Venture.

Final Investment Decision and Construction Commencement for Phoenix ISR Mine

In February 2026, Denison's board formally approved the Final Investment Decision to build the Phoenix ISR uranium mine at Wheeler River. Phoenix will use in-situ recovery (ISR) mining, where a specially formulated solution is injected underground to dissolve uranium within the rock formation, and the uranium-bearing solution is then pumped to the surface for processing. This method avoids large-scale underground excavation and can result in a reduced surface footprint compared to conventional mining. Site preparation and construction were scheduled to begin in March 2026, with a two-year build and first production targeted by mid-2028.

The total initial capital estimate was updated to approximately $600 million in January 2026 at a Class 2 level of precision, accounting for inflation, cost refinements, and project changes since the original 2023 feasibility study. The remaining engineering work, covering the latter phases of construction, is expected to be completed by mid-2026. Following a competitive tender, Wood Canada Limited was awarded the construction management contract in February 2026, and will be responsible for procurement, project controls, on-site safety oversight, and the construction of the full processing plant.

President and CEO David Cates commented: 

"With receipt of all regulatory approvals necessary to start construction, significant advancement of construction planning and procurement efforts, appointment of Wood Plc as construction manager, and a strong balance sheet, we are ready to commence site preparation for and construction of the Phoenix ISR uranium mine later this month, which positions Phoenix to become one of the few new sizeable sources of uranium production expected to come to the market before the end of the decade."

Regulatory Approvals and Community Engagement Agreements

After more than six years in the regulatory review process, Phoenix secured its final approvals in early 2026. In February 2026, the Canadian Nuclear Safety Commission (CNSC) approved the project's Environmental Assessment and issued the Licence to Prepare a Site and Construct, making Phoenix the first uranium mine in Canada to receive federal approval for construction in over 20 years. This followed the July 2025 provincial Environmental Assessment approval by Saskatchewan, completing all required regulatory approvals at both levels of government.

In December 2025, Denison signed an Impact Benefit Agreement with Métis Nation-Saskatchewan, 13 MN-S Locals, and two MN-S northern regions, confirming the Métis Parties' consent to and support for the development and operation of Wheeler River. A companion Exploration Agreement covering Denison's broader evaluation activities in the region was also executed.

Also in December 2025, Denison and the Ya'thi Néné Land and Resource Office announced the Nuhenéné Benefit Agreement with three First Nations groups, including Hatchet Lake Denesułiné, Black Lake Denesułiné, and Fond du Lac Denesułiné, along with four northern municipalities. The agreement covers Denison's Wheeler River and Waterbury Lake projects, as well as the company's minority positions in the Midwest and McClean Lake projects.

Milestones and Next Steps

With the FID approved, the construction licence issued, and a construction manager appointed, Denison's near-term focus is on the commencement and advancement of Phoenix construction. Completion of the remaining project engineering is expected by mid-2026. In parallel, the company plans to advance exploration across its broader Athabasca Basin portfolio, including follow-up drilling on targets identified through 2025 geophysical surveys and development of four new joint ventures with Skyharbour Resources on properties adjacent to Wheeler River. Denison has stated its objective is first uranium production from Phoenix by mid-2028.

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