Mr. David Cates reports

DENISON ACKNOWLEDGES APPLICATION FOR JUDICIAL REVIEW REGARDING PROVINCIAL ENVIRONMENTAL ASSESSMENT APPROVAL FOR WHEELER RIVER

Denison Mines Corp. has acknowledged an application for judicial review filed in the Court of King's Bench for Saskatchewan by the Peter Ballantyne Cree Nation (PBCN) against the government of Saskatchewan and the company.

Pursuant to the application, PBCN seeks an order setting aside the provincial ministerial approval under the Environmental Assessment Act (Saskatchewan) allowing Denison to proceed with the construction of a new uranium mine and processing plant at the Wheeler River project and remitting the decision back to the Saskatchewan Minister of the Environment for reconsideration. The application asserts that the government of Saskatchewan breached its duty to consult with PBCN and is required to further consult with PBCN regarding the project.

Denison has undertaken and continues to undertake extensive and impactful indigenous engagement and consultation efforts with respect to the project. Denison further believes the government of Saskatchewan undertook a thorough and meaningful consultation process in advance of the project's ministerial approval.

PBCN was provided with an opportunity to review the draft environmental impact statement for the project starting in November, 2022, and Denison has directly engaged with PBCN since March, 2023, when Denison first became aware of PBCN's interest in the project. Denison was not made aware of PBCN's intention to seek a judicial review and recently executed an environmental monitoring and capacity agreement with PBCN to support their independent environmental monitoring activities.

Denison is committed to reconciliation and works hard to listen to the perspectives of various interested parties, including PBCN, with whom Denison intends to maintain open communication. The company values indigenous knowledge and insight, and have sought to incorporate indigenous knowledge into its project planning processes, to ensure that its activities are designed to minimize impacts, wherever possible.

With respect to the application, Denison denies the claims made, and intends to refute several of the factual statements and vigorously defend against the orders requested.

About Wheeler River

Wheeler River is the largest undeveloped uranium project in the infrastructure-rich eastern portion of the Athabasca basin region, in Northern Saskatchewan. The project is host to the high-grade Phoenix and Gryphon uranium deposits, discovered by Denison in 2008 and 2014, respectively, and is a joint venture between Denison (90 per cent and operator) and JCU (Canada) Exploration Company Ltd. In August, 2023, Denison filed a technical report summarizing the results of (i) the feasibility study completed for ISR mining of the high-grade Phoenix uranium deposit and (ii) a cost update to the 2018 prefeasibility study for conventional underground mining of the basement-hosted Gryphon uranium deposit. More information on the studies is available in the technical report titled "NI 43-101 Technical Report on the Wheeler River Project Athabasca Basin, Saskatchewan, Canada" dated Aug. 8, 2023, with an effective date of June 23, 2023, a copy of which is available on Denison's website and under its profile on SEDAR+ and on EDGAR.

Based on the respective studies, both deposits have the potential to be competitive with the lowest-cost uranium mining operations in the world. Permitting efforts for the planned Phoenix ISR operation commenced in 2019 and are nearing completion with approval of the project's EA received from the Province of Saskatchewan and CNSC hearing dates set in the fall of 2025 for federal approval of the EA and project construction licence.

About Denison Mines Corp.

Denison is a uranium mining, exploration and development company with interests focused in the Athabasca basin region of Northern Saskatchewan, Canada. In addition to Denison's effective 95-per-cent interest in its flagship Wheeler River project, Denison's interests in Saskatchewan also include a 22.5-per-cent ownership interest in the McClean Lake joint venture (MLJV), which includes unmined uranium deposits (with mining at the McClean North deposit via the MLJV's Sabre mining method having commenced in 2025) and the McClean Lake uranium mill (currently utilizing a portion of its licensed capacity to process the ore from the Cigar Lake mine under a toll milling agreement), plus a 25.17-per-cent interest in the Midwest joint venture's Midwest Main and Midwest A deposits, and a 70.55-per-cent interest in the Tthe Heldeth Tue (THT) and Huskie deposits on the Waterbury Lake property. The Midwest Main, Midwest A, THT and Huskie deposits are located within 20 kilometres of the McClean Lake mill. Taken together, Denison has direct ownership interests in properties covering approximately 384,000 hectares in the Athabasca basin region.

Additionally, through its 50-per-cent ownership of JCU (Canada) Exploration Company Ltd. (JCU), Denison holds additional interests in various uranium project joint ventures in Canada, including the Millennium project (JCU, 30.099 per cent), the Kiggavik project (JCU, 33.8118 per cent) and Christie Lake (JCU, 34.4508 per cent).

In 2024, Denison celebrated its 70th year in uranium mining, exploration and development, which began in 1954 with Denison's first acquisition of mining claims in the Elliot Lake region of Northern Ontario.

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