Mr. David Cates reports

PETER BALLANTYNE CREE NATION WITHDRAWS JUDICIAL REVIEW AND CONFIRMS SUPPORT FOR THE WHEELER RIVER PROJECT

Peter Ballantyne Cree Nation (PBCN) has withdrawn its judicial review application previously filed in the Court of King's Bench for Saskatchewan related to the environmental assessment approval granted by the Province of Saskatchewan for the Phoenix in-situ recovery (ISR) uranium mine. As a result of further engagement with PBCN, Denison Mines Corp. is also pleased to report that PBCN has now formally provided its consent to and support for the development and operation of Denison's Wheeler River project in Northern Saskatchewan.

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. (JCU, 10 per cent). In August, 2023, Denison filed a technical report summarizing the results of (i) Phoenix FS; and (ii) a cost update to the 2018 prefeasibility study for conventional underground mining of the basement-hosted Gryphon uranium deposit. 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, culminating in the July, 2025, approval of the project's environmental assessment (EA) by the Province of Saskatchewan and the February, 2026, approval of the project's EA and the grant of the construction licence by the Canadian Nuclear Safety Commission. Site preparation and early works construction commenced for Phoenix in March, 2026, with first production targeted for 2028. More information 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, and an update to estimated Phoenix initial capital costs disclosed by press release dated Jan. 2, 2026, copies of which are available on Denison's website and under its profile on SEDAR+ and on EDGAR.

About Denison Mines Corp.

Denison is a leading uranium 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 include a 22.5-per-cent ownership interest in the McClean Lake joint venture (MLJV), which includes uranium deposits (with mining at the McClean North deposit having commenced in 2025 using the MLJV's Sabre mining method) 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 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 457,000 hectares in the Athabasca basin region.

Additionally, through its 50-per-cent ownership of JCU (Canada) Exploration Company Ltd. (JCU), Denison holds 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.

We seek Safe Harbor.