Denison Begins Construction at Phoenix as Uranium Sales Commitments Approach 16 Million Pounds

• In February 2026, Phoenix received all required federal and provincial approvals for construction, making it the first uranium mine in Canada to reach this stage in more than 20 years, after which Denison's board approved the Final Investment Decision (FID) for the project.
• Site preparation and early works are underway at Wheeler River, with tree clearing, a helipad, and aggregate production completed by end of April 2026; full-scale construction is targeted to commence before the end of Q2 2026.
• Wood Canada Limited has been appointed as construction manager for Phoenix, covering procurement, construction management, site safety oversight, and project controls under an integrated arrangement with Denison.
• The post-FID initial capital cost estimate for Phoenix is approximately $600 million, with first uranium production targeted for mid-2028.
• Contracted uranium sales commitments stand at nearly 8 million pounds of U3O8, with advanced negotiations covering a further 8 million pounds, bringing combined commitments to approximately 16 million pounds.

Denison Mines Corp. (TSX: DML / NYSE American: DNN) is a Canada-based uranium mining, exploration, and development company with interests focused in the Athabasca Basin region of northern Saskatchewan. The company holds a 95% interest in the Wheeler River Uranium Project, the largest undeveloped uranium project in the eastern portion of the Basin, which hosts both the Phoenix and Gryphon deposits. Based on respective feasibility studies, both deposits have the potential to be competitive with the lowest-cost uranium mining operations in the world. Denison also holds a 22.5% interest in the McClean Lake Joint Venture, which includes an operating uranium mill and the recently restarted McClean North mine, as well as interests in several other regional deposits covering approximately 457,000 hectares in total. Through its 50% ownership of JCU (Canada) Exploration Company, Denison holds further interests in uranium projects across Canada. In 2024, the company marked its 70th year in uranium mining and development.

Q1 2026 Financial and Operational Results Including Phoenix Early Works Commencement

Denison filed its first quarter 2026 financial statements on 12 May 2026, covering the three months ended 31 March 2026. Operational activity during the period centred on the receipt of final regulatory approvals for Phoenix and the initial mobilisation of the construction team to the Wheeler River property.

In February 2026, Canada's nuclear safety regulator, the Canadian Nuclear Safety Commission (CNSC), approved the Environmental Assessment (EA) for Phoenix and issued a Construction Licence, representing the final approvals required to commence construction. With provincial approvals from Saskatchewan already secured, Phoenix became the first uranium mine in Canada to receive federal construction approval in more than 20 years.

Following receipt of the CNSC approvals, Denison's board approved the Final Investment Decision (FID) for Phoenix construction. A joint on-site project management team comprising Denison personnel and specialists from Wood Canada Limited subsequently mobilised to Wheeler River in early March 2026. At the company's 22.5%-owned McClean Lake operation, mining activity at the McClean North SABRE mine was minimal during the quarter, with work focused on resource confirmation drilling ahead of a planned resumption of active mining in Q2 2026.

Phoenix Site Preparation and Construction Progress Toward 2028 Production

Phoenix is designed to use a method called In-Situ Recovery (ISR), in which a specially formulated solution is injected underground to dissolve uranium in place, and the uranium-bearing liquid is then pumped to surface for processing. This approach differs from conventional underground or open-pit mining, which requires excavating ore from the ground. Because Phoenix is a greenfield development, built on previously undeveloped land, significant site preparation is required before full-scale construction can begin.

By the end of April 2026, the Denison-Wood team had completed a number of schedule-critical early works activities. 

President and CEO David Cates said:

"In less than two months of on-site activity, our dedicated teams have completed (i) tree clearing activities across the primary mine site area, (ii) installation of construction management facilities, (iii) construction of our on-site helipad, (iv) civil works for the concrete batch plant pad, and (v) commencement of aggregate production at a nearby quarry." 

Civil works for access roads and clearings to establish a future site airstrip are also in progress.

Based on early works completed to date, Denison expects to ramp construction staffing and activities to a full-scale rate before the end of Q2 2026. Once full-scale construction commences, the build is expected to take approximately two years, targeting first uranium production in mid-2028. Cates noted that widespread flooding affecting road networks in northern Saskatchewan is being closely monitored, as it may affect the mobilisation of heavy equipment and supplies to site if conditions do not improve.

Uranium Sales Book Growth and Project Financing Strategy

Proceeds from the sale of Denison's physical uranium holdings and inventory form a key part of the company's financing plan for Phoenix. The physical uranium holdings were originally acquired in 2021 and have since been the basis for contracted sales to nuclear power utilities and industry intermediaries at market and negotiated prices.

In Q1 2026, Denison agreed to sell 550,000 pounds of U3O8 (uranium oxide, the standard commercial form of uranium) for delivery between Q2 2026 and Q1 2027 at an average price of US$99.07 per pound. At quarter-end, a total of 1,350,000 pounds were committed for near-term delivery: 950,000 pounds at a fixed average of US$92.05 per pound, representing gross proceeds of approximately US$87.5 million, with the remaining 400,000 pounds subject to market pricing. 

President and CEO David Cates commented: 

"In the first quarter, we entered near-term sales commitments with an average realized price over US$99/lb U3O8 for deliveries within a year. These sales are part of our Phoenix project financing efforts stemming from our physical uranium purchase from 2021, and demonstrate how our disciplined long-term strategy has facilitated significant participation in a rising uranium price environment."

The total uranium sales book now includes firm contracted commitments for nearly 8 million pounds of U3O8, with advanced negotiations covering a further 8 million pounds, for a combined total of approximately 16 million pounds. Customers include North American nuclear power utilities collectively responsible for over 50 nuclear reactors, as well as reputable industry intermediaries. Pricing structures include market-related and base-escalated arrangements, with Cates noting that base-escalated prices have recently been observed above US$100 per pound on a present-value basis, a level above what industry publications currently report.

Looking Ahead

Denison's near-term priorities include completing site preparation, ramping to full-scale construction before the end of Q2 2026, and progressing uranium sales negotiations. At McClean Lake, the resumption of active mining at the McClean North SABRE operation is expected in Q2 2026 following the completion of resource confirmation drilling. First uranium production at Phoenix remains targeted for mid-2028.

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