Denison Reports Financial and Operational Results for Q3’2024, Including Positive Progress on Phoenix Engineering and Regulatory Review

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Denison Mines Corp.

1100 – 40 University Ave

Toronto, ON M5J 1T1

www.denisonmines.com

PRESS RELEASE

Denison Reports Financial and Operational Results for Q3’2024, Including

Positive Progress on Phoenix Engineering and Regulatory Review

Toronto, ON – November 7, 2024. Denison Mines Corp. (‘Denison’ or the ‘Company’) (TSX: DML, NYSE American:

DNN) today filed its Condensed Consolidated Financial Statements and Management’s Discussion & Analysis (‘MD&A’)

for the three and nine months ended September 30, 2024. Both documents will be available on the Company’s website

at www.denisonmines.com, SEDAR+ (at www.sedarplus.ca) and EDGAR (at www.sec.gov/edgar.shtml). The highlights

provided below are derived from these documents and sho uld be read in conjunction with them. All amounts in this

release are in Canadian dollars unless otherwise stated.

David Cates, President and CEO of Denison commented, “Our third quarter report includes an update on the positive

progress of our engineering and regulatory approval efforts for our planned Phoenix In-Situ Recovery (‘ISR’) uranium

mining operation. We continue to rapidly advance detailed design engineering efforts and achieved completion of 45%

of total engineering by the end of the third quarter. Long-lead procurement efforts continued to ramp up. Currently, $21

million in milestone payments or commitm ents have been made for items included in our estimates of initial project

capex, with several additional procurement packages in progress.

On the regulatory side, we are pleased to report that subst antially all outstanding information requests (‘IRs’) from the

Canadian Nuclear Safety Commission’s (‘CNSC’) review of the Wheeler River draft Envi ronmental Impact Statement

(‘EIS’) have been resolved, and the Federal review process is nearing completion. Given this positive progress with the

Federal review, we have opted to submit a final Provincial EIS to the Saskatchewan Ministry of Environment to advance

the process of obtaining formal approval from the Province.

Beyond Wheeler River, we are pleased with the progress of the SABRE program at the McClean North deposit, which

remains on track for production in 2025. Our team is also ac tive on our portfolio of other development and exploration

projects, with study work advancing on both the Midwest project and the Tthe Heldeth Túé ('THT') deposit, with the

potential to result in updated or new technical studies in the coming months.

Also notable is our recent transaction with Foremost Clean Energy, which involves Denison optioning up to 70% of its

interests in a portfolio of 10 exploration properties. The tr ansaction was designed to amplify our exposure to future

discovery by encouraging exploration on – and retaining significant ownership of - properties that would otherwise have

received little attention from Denison with our current focus on development and mining-stage projects.”

Q3 2024 MD&A Highlights

 Signing of Wheeler River Benefit Agreements with Kineepik Métis Local #9 and the Village of Pinehouse Lake

In July 2024, Denison announced the signing of a Mutual Benefits Agreement (‘MBA’) with Kineepik Métis Local #9

(‘KML’), and a Community Benefit Agreement (‘CBA’) with the northern Village of Pinehouse Lake (‘Pinehouse’), in

support of the development and operation of Denison’s 95% owned Wheeler River Project.

The MBA acknowledges that the project is located within KML’s Land and Occupancy Area in northern Saskatchewan

and provides KML’s consent and support to advance t he project. Additionally, the MBA recognizes that the

development and operation of the proj ect can support KML in advancing it s social and economic development

aspirations while mitigating the impacts on the local environment and KML members. The MBA provides KML and

its Métis members an important role in environmental moni toring and commits to the sharing of benefits from the

successful operation of the project – including benefi ts from community investment, business opportunities,

employment and training opportunities, and financial compensation.

The CBA acknowledges that Pinehouse is the closest resident ial community to the project by road, which relies on

much of the same regional infrastructure that Denison will rely on as it advances the project. Pinehouse has provided

its consent and support for the project, while Denison, on behalf of the Wheeler River Joint Venture, is committed to

helping Pinehouse develop its own capacity to take advantage of economic and other development opportunities in

connection with the advancement and operation of the project.

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 Continued Advancement of Phoenix Engineering and Federal Regulatory Review of the Draft EIS

During the third quarter, the Company continued to focu s its efforts on the advancement of the Phoenix project

towards a final investment decision in support of its objective to achieve first production by 2027 / 2028, including:

 Phoenix engineering activities are advancing within expected timelines to support a financial investment

decision (‘FID’) by mid-2025. Total engineering completion at end of the third quarter was 45%, supported by

finalization of process design, piping and instrument ation diagrams (P&ID’s), hazard and operability studies

(‘HAZOPs’), as well as the selection of major process equipment and electrical distribution infrastructure.

 The review of the draft EIS continues to advance and Denison has been in regular contact with CNSC staff to

support the conclusion of any remaining IRs. In Sept ember 2024, Denison receiv ed confirmation that the

majority of outstanding IRs have been resolved, which s uggests that the Federal re view process is nearing

completion.

 Option of Non-Core Exploration Projects to Foremost Clean Energy Ltd.

In September 2024, Denison executed an option agreement with Foremost Clean Energy Ltd (‘Foremost’), which

grants Foremost an option to acquire up to 70% of Denison's interests in 10 non-core uranium exploration properties

(collectively, the ‘Foremost Transaction’). Pursuant to the Foremost Transaction, Foremost would acquire such total

interests upon completion of a combination of direct pay ments to Denison and funding of exploration expenditures

with an aggregate value of up to approximately $30 million. The Foremost Transaction provides the following benefits

to Denison:

 Collaboration with Foremost is expected to increase exploration activity on a portfolio of non-core Denison

properties with the potential to incr ease the probability of discovery within Denison's vast Athabasca Basin

exploration portfolio.

 In October 2024, Denison received an upfront payment in Foremost common shares (representing a ~19.95%

ownership interest in Foremost). If Foremost completes the remaining two phases of the Foremost Transaction

Denison will receive further cash and/or common share milestone payments of $4.5 million and Foremost will

fund $20 million in project exploration expenditures.

 In addition to becoming Foremost’s largest shareholder , Denison retains direct interests in the optioned

exploration properties and also secures certain strategic pre-emptive rights to participate in future exploration

success from the optioned properties.

About Denison

Denison Mines Corp. was formed under the laws of Ontario and is a reporting issuer in all Canadian provinces and

territories. Denison’s common shares are listed on the To ronto Stock Exchange (the ‘TSX’) under the symbol ‘DML’

and on the NYSE American exchange under the symbol ‘DNN’.

Denison is a uranium mining, exploration and development company with interests focused in the Athabasca Basin

region of northern Saskatchewan, Canada. The Company has an effective 95% interest in its flagship Wheeler River

Uranium Project, which is the largest undeveloped uranium proj ect in the infrastructure rich eastern portion of the

Athabasca Basin region of northern Sa skatchewan. In mid-2023, the Phoeni x FS was completed for the Phoenix

deposit as an ISR mining operation, and an update to the previously prepared 2018 Pre-Feasibility Study (‘PFS’) was

completed for Wheeler River’s Gryphon deposit as a c onventional underground mining operation. Based on the

respective studies, both deposits have t he 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 Enviro nmental Impact Study (‘EIS’) submitted for regulatory and

public review in October 2022.

Denison’s interests in Saskatchewan also include a 22.5% ownership interest in the McClean Lake Joint Venture

(‘MLJV’), which includes unmined uranium deposits (planned for extraction via the MLJV’s SABRE mining method

starting 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% interest in the Midwest Joint Venture

(‘MWJV’)’s Midwest Main and Midwest A deposits, and a 69.44% interest in the Tthe Heldeth Túé (‘THT’) and Huskie

deposits on the Waterbury Lake Property (‘Waterbury’). The Midwest Main, Midwest A, THT and Huskie deposits are

located within 20 kilometres of the McClean Lake mill. Taken together, the Company has direct ownership interests in

properties covering ~384,000 hectares in the Athabasca Basin region.

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Additionally, through its 50% ownership of JCU (Canada) Explorat ion Company, Limited (‘JCU’), Denison holds

interests in various uranium project joint ventures in Ca nada, including the Millennium project (JCU, 30.099%), the

Kiggavik project (JCU, 33.8118%) and Christie Lake (JCU, 34.4508%).

Technical Disclosure and Qualified Person

The technical information contained in this press release has been reviewed and approved by Chad Sorba, P.Geo.,

Denison’s Vice President Technical Services & Project Evaluation, and Andy Yackulic, P.Geo., Denison’s Vice

President Exploration, who are both Qualified Persons in accordance with the requirements of NI 43-101.

For more information, please contact

David Cates (416) 979-1991 ext. 362

President and Chief Executive Officer

Geoff Smith (416) 979-1991 ext. 358

Vice President Corporate Development & Commercial

Follow Denison on Twitter @DenisonMinesCo

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Certain information contained in this pre ss release constitutes ‘forward-looking info rmation’, within the meaning of the applic able

United States and Canadian legislation conc erning the business, operations and financ ial performance and condition of Denison.

Generally, these forward-looking statements c an be identified by the use of forward-look ing terminology such as ‘plans’, ‘expects’,

‘budget’, ‘scheduled’, ‘estimates’, ‘forecasts’, ‘intends’, ‘anticipates’, or ‘believes’, or the negatives and/or variations of such words and

phrases, or state that certain actions, events or results ‘may’, ‘could’, ‘would’, ‘might’ or ‘will be taken’, ‘occur’, ‘be achieved’ or ‘has

the potential to’.

In particular, this press release contains forward-looking information pertaining to the following: projections with respect to exploration,

development and expansion plans and objectives, including the scope, objectives and in terpretations of FS, PFS and the Wheeler

River technical de-risking process for the proposed ISR operation for the Phoenix depos it; expectations with respect to the EA, EIS

and licensing and permitting for propos ed operations at Wheeler River; anticipated benefits of the transaction with Foremost;

expectations regarding the restart of mini ng operations at McClean Lake; expectations regarding the assessment of the amenabili ty

of ISR for THT and advancement of technical studies for the Midwest deposit; expectations regarding the performance of the uranium

market and global sentiment regarding nucl ear energy; expectations rega rding Denison’s joint venture ownership interests; and

expectations regarding the objectives and continuity of its agreements with third parties. Statements relating to ‘mineral reserves’ or

‘mineral resources’ are deemed to be forward-looking information, as they involve the implied assessment, based on certain estimates

and assumptions that the mineral reserves and mineral resources described can be profitably produced in the future.

Forward looking statements are based on the opinions and estimates of management as of the date such statements are made, and

they are subject to known and unknown risks, uncertainties and other factors that may c ause the actual results, level of activi ty,

performance or achievements of Denison to be materially different from those expre ssed or implied by such forward-looking

statements. For example, the results and underlying assumptions and interpretations of the FS and PFS may not be maintained after

further testing or be representative of ac tual conditions within the applicable deposit s. In addition, Denison may decide or ot herwise

be required to discontinue testing, evaluati on, engineering, and development work if it is unable to maintain or otherwise secu re the

necessary approvals or resources (such as testing facilities, capital funding, etc.). Denison believes that the expectations reflected in

this forward-looking information are reasonable, but no assurance can be given that these expectations will prove to be accurate and

results may differ materially from those anticipated in this fo rward-looking information. For a discussion in respect of risks and other

factors that could influence forward-looking events, please refer to the factors discu ssed in the Company’s Annual Information Form

dated March 28, 2024 under the heading ‘Risk Factors’. These factors are not, and should not be, construed as being exhaustive.

Accordingly, readers should not place undue re liance on forward-looking statements. The forward-looking information contained i n

this press release is expressly qualified by this cautionary statement. Any forward-looking information and the assumptions made with

respect thereto speaks only as of the date of this press release. Denison does not undertake any obligation to publicly update or revise

any forward-looking information after the date of this press rel ease to conform such information to actual results or to change s in

Denison's expectations except as otherwise required by applicable legislation.