Blueprint

DENISON MINESCORP.

/s/ Amanda Willett

Date: August 5,2025

AmandaWillett

VicePresident Legal and Corporate Secretary

Toronto, ON – August 5,2025. Denison Mines Corp. (“Denison” or the “Company”) (TSX: DML; NYSE American: DNN) is pleasedto announce that it has received Ministerial approval underThe EnvironmentalAssessment Act (Saskatchewan)to proceed with the development of the In-Situ Recovery(“ISR”) uranium mine planned for the Wheeler RiverProject (the “Project”).

Aspart of Denison’s strategy to effectively harmonize theFederal and Provincial Environmental Assessment (the“EA”) for the Project, the Provincial EA was submittedfor final approval in late 2024 after Denison successfullycompleted multiple key milestones in the Federal regulatoryprocess, including completion of the Canadian Nuclear SafetyCommission’s (“CNSC”) rigorous technical reviewphase, and acceptance by the CNSC of the Company's finalEnvironmental Impact Statement (“EIS”) for the Project.As a result of this approach, the Federal and Provincial EAs forthe Project are substantially the same and no subsequent revisionsfor conformance are expected to be required.

“Saskatchewanis the world’s second-largest uranium producer, and remains adestination of choice for mining investment due to our abundantnatural resources and strong regulatory environment,”Saskatchewan Premier Scott Moesaid. “Theprovince continues to be a national leader in safe and sustainablemining practices, well positioning Canada as an emerging energysuperpower. As demand for these resources increase, we are pleasedto see this project move ahead, further enhancingSaskatchewan’s world class energy sector, while bringing newjobs and opportunities to northerncommunities.”

“Iwould like to congratulate Denison Mines on this significantproject milestone with their Wheeler RiverProject”, commented theHonourable Travis Keisig, Saskatchewan Minister ofEnvironment. “We look forward toworking with Denison as this project progresses and are excitedthat they have chosen Saskatchewan as a place to dobusiness.”

David Cates, President and CEO of Denison,commented, “Wethank the Province of Saskatchewan for entrusting Denison toproceed with the development of the Project, which is expected toset a superior standard of sustainability as the first ISR uraniummine in Canada. We applaud the work of the Provincial Government touphold the province’s rigorous environmental regulations,while simultaneously recognizing the important role that thenatural resources sector can play in driving societal wellbeing.The Province of Saskatchewan is truly a leading jurisdiction forsustainable natural resource investments.

I’d also like to applaud our own environmental, regulatory,sustainability and technical teams for working closely with theSaskatchewan Ministry of the Environment, Indigenous nations, localcommunities, and other interested parties during the EA process.Importantly, completion of the provincial EA represents one of thefinal regulatory milestones necessary for Denison to commenceconstruction of the Phoenix ISR mine, which is on track to becomeCanada’s next new large-scale uraniummine.”

Withthe Provincial EA approved, the remaining regulatory requirementsto commence construction of the ISR mine planned for the Phoenixdeposit include receipt of the Provincial Pollutant ControlFacility Permit, as well as the Federal approval of the EA andreceipt of the Federal License to Prepare the Site & Construct.Both outstanding Federal approvals are the subject of the CNSCpublic hearings for the Project scheduled in October and December2025.

Wheeler River is the largest undeveloped uranium project in theinfrastructure-rich eastern portion of the Athabasca Basin region,in northern Saskatchewan. The project is host to the high-gradePhoenix and Gryphon uranium deposits, discovered by Denison in 2008and 2014, respectively, and is a joint venture between Denison (90%and operator) and JCU (Canada) Exploration Company Limited(“JCU”, 10%). In August 2023, Denison filed a technicalreport summarizing the results of (i) the feasibility studycompleted for ISR mining of the high-grade Phoenix uranium depositand (ii) a cost update to the 2018 Pre-Feasibility Study forconventional underground mining of the basement-hosted Gryphonuranium deposit. More information on the studies is available inthe technical report titled “NI 43-101 Technical Report onthe Wheeler River Project Athabasca Basin, Saskatchewan,Canada” dated August 8, 2023, with an effective date of June23, 2023, a copy of which is available on Denison's website andunder its profile on SEDAR+ at www.sedarplus.ca and on EDGAR atwww.sec.gov/edgar.

Based on the respective studies, both deposits have the potentialto be competitive with the lowest-cost uranium mining operations inthe world. Permitting efforts for the planned Phoenix ISR operationcommenced in 2019 and are nearing completion with approval of theproject’s EA received from the Province of Saskatchewan andCNSC hearing dates set in the fall of 2025 for Federal approval ofthe EA and project construction license.

Denison is a uranium mining, exploration and development companywith interests focused in the Athabasca Basin region of northernSaskatchewan, Canada. In addition to Denison’s effective 95%interest in its flagship Wheeler River Project, Denison’sinterests in Saskatchewan also include a 22.5% ownership interestin the McClean Lake Joint Venture (“MLJV”), whichincludes unmined uranium deposits (with mining at the McClean Northdeposit via the MLJV's SABRE mining method having commenced in2025) and the McClean Lake uranium mill (currently utilizing aportion of its licensed capacity to process the ore from the CigarLake mine under a toll milling agreement), plus a 25.17% interestin the Midwest Joint Venture’s Midwest Main and Midwest Adeposits, and a 70.55% interest in the Tthe Heldeth Túé(“THT”) and Huskie deposits on the Waterbury LakeProperty. The Midwest Main, Midwest A, THT and Huskie deposits arelocated within 20 kilometres of the McClean Lake mill. Takentogether, Denison has direct ownership interests in propertiescovering ~384,000 hectares in the Athabasca Basinregion.

Additionally, through its 50% ownership of JCU (Canada) ExplorationCompany, Limited (“JCU”), Denison holds additionalinterests in various uranium project joint ventures in Canada,including the Millennium project (JCU, 30.099%), the Kiggavikproject (JCU, 33.8118%), and Christie Lake (JCU,34.4508%).

Certain information contained in this press release constitutes‘forward-looking information’ within the meaning of theapplicable United States and Canadian legislation, concerning thebusiness, operations and financial performance and condition ofDenison. Generally, these forward-looking statements can beidentified by the use of forward-looking terminology such as‘potential’, ‘plans’,‘expects’, ‘budget’,‘scheduled’, ‘estimates’,‘forecasts’, ‘intends’,‘anticipates’, or ‘believes’, or thenegatives and/or variations of such words and phrases, or statethat certain actions, events or results ‘may’,‘could’, ‘would’, ‘might’ or‘will’ ‘be taken’, ‘occur’ or‘be achieved’.

In particular, this press release contains forward-lookinginformation pertaining to the following: expectations with respectto the EA process, including the filing of the final EIS and theresults and objectives thereof; expectations regarding regulatoryreviews and processes, including hearings with the CNSC Commission;and expectations regarding its joint venture ownership interests,including plans for mining and the use of SABRE by the MLVJ, andthe continuity of its agreements with its partners and thirdparties.

Forward-looking statements are based on the opinions and estimatesof management as of the date such statements are made, and they aresubject to known and unknown risks, uncertainties and other factorsthat may cause the actual results, level of activity, performanceor achievements of Denison to be materially different from thoseexpressed or implied by such forward-looking statements. Denisonbelieves that the expectations reflected in this forward-lookinginformation are reasonable but no assurance can be given that theseexpectations will prove to be accurate and results may differmaterially from those anticipated in this forward-lookinginformation. For a discussion in respect of risks and other factorsthat could influence forward-looking events, please refer to thefactors discussed in Denison’s Annual Information Form datedMarch 28, 2025 under the heading ‘Risk Factors’ or insubsequent quarterly financial reports. These factors are not, andshould not be construed as being, exhaustive.

Accordingly, readers should not place undue reliance onforward-looking statements. The forward-looking informationcontained in this press release is expressly qualified by thiscautionary statement. Any forward-looking information and theassumptions made with respect thereto speaks only as of the date ofthis press release. Denison does not undertake any obligation topublicly update or revise any forward-looking information after thedate of this press release to conform such information to actualresults or to changes in Denison's expectations except as otherwiserequired by applicable legislation.

Exhibit Number		Description

99.1		Press release dated August 5,2025