Mr. David Cates reports

DENISON ANNOUNCES SIGNING OF IMPACT BENEFIT AGREEMENT AND EXPLORATION AGREEMENT WITH METIS NATION-SASKATCHEWAN, MN-S NR-1, AND MN-S NR-3

Denison Mines Corp. has signed an impact benefit agreement (IBA) between Denison and the Metis Nation-Saskatchewan (MN-S), 13 MN-S Locals, MN-S Northern Region 1 and MN-S Northern Region 3 (collectively, the Metis parties). The IBA confirms the Metis parties' consent to and support for the development and operation of Denison's flagship Wheeler River project in Northern Saskatchewan. In addition, the parties have also entered into an exploration agreement covering Denison's exploration and evaluation activities within MN-S NR-1 and MN-S NR-3 of the Metis Homeland.

MN-S president Glen McCallum said: "Denison Mines recognized its duty to consult with MN-S regions, MN-S locals and communities on the Wheeler River project early in the planning stages. All parties have been negotiating since 2019. The MN-S commends Denison's commitment to environmental reclamation postproject and stability for citizens into the future. Today's IBA not only represents enormous economic opportunities for Metis families, but a milestone in our government's relationship with Denison and other industry partners."

David Cates, president and chief executive officer of Denison, commented: "We extend our sincere appreciation to the leadership of the MN-S, MN-S NR-1, MN-S NR-3 and the 13 MN-S Locals for trusting Denison to advance the Wheeler River project within the Metis Homeland. Since the beginning of our engagement with the MN-S, our team has remained deeply committed to building a long-lasting relationship grounded in trust, transparency and mutual respect. Formalizing both the IBA and the exploration agreement reflects the progress we have made together, and also our shared commitment to ensuring that the interests, knowledge and voices of Metis citizens in Saskatchewan are meaningfully incorporated into the construction and future operation of the project and Denison's exploration and evaluation activities in MN-S NR-1 and MN-S NR-3."

Laura Burnouf, regional director of MN-S NR-1, said: "Northern Saskatchewan is not only rich in natural resources, it is vibrant with the culture, tradition and language of a distinct people. Denison's engagement with our Metis communities and its focus on local talent brings economic and employment opportunities to our region and surrounding communities at a time when we face challenges with homelessness and addictions. The strong partnership between all of our impacted Metis regions and locals, MN-S, and Denison Mines is a reflection of how we believe in progress and are more than willing to collaborate with industry to better the outlook for our citizens."

Regional director of MN-S NR3, Minister Brennan Merasty, remarked: "Respecting our inherent and constitutionally protected rights as Metis citizens, our communities in the north have been engaged with Denison for six years. Today's signing means our region and surrounding communities will see significant cultural, economic and employment benefits to be provided through this partnership. Our citizens' voices deserved to be at the negotiating table, and we will continue to work alongside Denison as the Wheeler River project advances forward."

The IBA was entered into by Denison (on its own behalf and as operator on behalf of the Wheeler River joint venture), the MN-S, MN-S NR-1, MN-S NR-3 and each of the following MN-S Locals within MN-S NR-1 or MN-S NR-3, which comprised citizens who live and practice traditional activities in the vicinity of the Wheeler River project: Uranium City Local 50, Stony Rapids Local 80, La Ronge Local 19, Weyakwin Local 16, Timber Bay Local 20, Patuanak Local 82, Ile-a-la-Crosse Local 21, Canoe River Local 174, Jans Bay Local 38, Beauval Local 37, Cole Bay Local 41, Dore/Sled Lake Local 67 and Green Lake Local 5.

Impact benefit agreement

The IBA acknowledges that the project is located within the Metis Homeland and emphasizes a shared commitment to ensuring that the successful execution of the project meaningfully supports the Metis parties' broader social and economic priorities. This agreement sets out a framework for a long-term cooperative relationship grounded in openness, environmental stewardship and respect for Metis interests. The IBA affirms that project development can contribute to long-term community well-being while also reinforcing the joint responsibility to protect the surrounding lands, waters and wildlife. The parties commit to reducing environmental risks while upholding the values central to the Metis parties.

The IBA also includes specific commitments for sharing the benefits generated by the project, including community investment initiatives, contracting and business development opportunities, training and employment pathways, designated forms of financial participation, and opportunities for the Metis parties and their citizens to participate in environmental monitoring.

Together the commitments in the IBA reflect a joint vision for collaboration and establish a framework through which Denison and the Metis parties can work side by side to ensure that the project contributes to a sustainable and resilient future for Metis citizens in Saskatchewan.

Exploration agreement

The exploration agreement extends the cooperative and mutually beneficial relationship between Denison and the Metis parties beyond the project and covers all of Denison's other majority owned and operated exploration and evaluation projects within MN-S NR-1 and MN-S NR-3. The Metis parties consent to Denison's exploration and evaluation activities in the region and Denison commits to support the Metis parties' interests in community development, benefits sharing, environmental protection and monitoring, and sustainable and predictable consultation and engagement processes.

Through this co-operative approach, the parties aim to ensure Denison's future projects are positively advanced through the exploration and evaluation phases in a manner that is informed by and is fully respectful of the rights, knowledge and interests of the Metis parties.

About Denison Mines Corp.

Denison is a leading uranium mining, development and exploration company with interests focused in the Athabasca basin region of Northern Saskatchewan, Canada. Denison has an effective 95-per-cent interest in its flagship Wheeler River uranium project, which is the largest undeveloped uranium project in the infrastructure rich eastern portion of the Athabasca basin region of Northern Saskatchewan.

In mid-2023, the Phoenix feasibility study was completed for the Phoenix deposit as an ISR mining operation and an update to the previously prepared 2018 prefeasibility study was completed for Wheeler River's Gryphon deposit as a conventional underground mining operation. 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 in July, 2025, of the project's EA by the province of Saskatchewan and commencement in October, 2025, of the Canadian Nuclear Safety Commission Hearings for federal approval of the EA and project construction licence. The hearing is scheduled to continue and be concluded during the week of Dec. 8, 2025.

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 McClean North deposit via the MLJV's Sabre mining method having commenced in July, 2025, using the MLJV's Sabre mining method) and the McClean Lake uranium mill (currently utilizing a portion of its licenced 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 384,000 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) 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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