Mr. David Cates reports

DENISON ANNOUNCES EXCLUSIVE ACQUISITION OF MAXPERF TOOL SYSTEMS, ENHANCING DENISON'S LEADERSHIP IN ISR MINING IN THE ATHABASCA BASIN

Denison Mines Corp. has completed an acquisition of fixed and mobile MaxPERF tool systems from Penetrators Canada Inc. Significantly, Penetrators has also agreed to work exclusively with Denison with respect to the use of the MaxPERF tool systems for uranium mining applications, and related services, in Saskatchewan for a 10-year period.

David Cates, Denison's president and chief executive officer, commented, "We are pleased to enter into this exclusive arrangement with Penetrators and add the MaxPERF technology to Denison's in-house ISR mining tool kit, which we believe will further enhance our existing and significant competitive advantage in deploying the low-cost in situ recovery (ISR) mining method to our high-grade uranium deposits in the Athabasca basin."

Chad Sorba, Denison's vice-president, technical services and project evaluation, added: "With Denison on track to operate the first ISR uranium mine in the Athabasca basin region, the acquisition of the MaxPERF tool systems represents another important step in our preparations for project execution and commercial ISR mining. MaxPERF has historically been used in the oil and gas sector and was identified by Denison as a potentially useful tool for permeability enhancement to support ISR mining. In 2023, Denison completed a groundbreaking multiyear technical derisking program at the company's Phoenix deposit, which rigorously assessed and successfully applied the MaxPERF system to enhance deposit permeability -– including its deployment as part of the highly successful feasibility field test program. Given the demonstrated success of the technology, we look forward to continuing to work together with the team at Penetrators to use MaxPERF in this new commercial application."

Dwayne West, president of Penetrators, further commented: "Denison's ISR uranium mining technique is an outstanding application for the MaxPERF technology -- permeability exposure that will be exploited for both injectivity and productivity purposes. Penetrators is very pleased with the relationship we have built with Denison and this partnership is a positive next step."

Permeability enhancement techniques, such as the use of the MaxPERF tool, are designed to improve hydraulic responses and interwell connectivity within an ISR mining pattern, essentially engineering additional access to the natural permeability within the deposit. The MaxPERF tool has been successfully deployed several times as a method of permeability enhancement in ISR field studies conducted on the company's potential ISR mining projects, including at Denison's flagship Phoenix uranium deposit.

About Denison Mines Corp.

Denison is a uranium exploration and development 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, a feasibility study was completed for Wheeler River's Phoenix deposit as an ISR mining operation, and an update to the previously prepared PFS 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 have advanced significantly, with licensing in progress and a draft environmental impact statement submitted for regulatory and public review in October, 2022.

Denison's interests in Saskatchewan also include a 22.5-per-cent ownership interest in the McClean Lake joint venture, which owns several uranium deposits and the McClean Lake uranium mill that is contracted to process the ore from the Cigar Lake mine under a toll milling agreement, plus a 25.17-per-cent interest in the Midwest Main and Midwest A deposits, and a 67.41-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.

Through its 50-per-cent ownership of JCU (Canada) Exploration Company Ltd., 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).

Denison's exploration portfolio includes further interests in properties covering approximately 285,000 hectares in the Athabasca basin region.

Qualified person

The technical information contained in this release has been reviewed and approved by Mr. Sorba, PGeo, Denison's vice-president, technical services and project evaluation, a qualified person in accordance with the requirements of Canadian National Instrument 43-101.

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