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Denison CFO on Temporary Medical Leave of Absence, Interim CFO Appointed

Management Changes

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  Denison Mines Corp. 

1100 – 40 University Ave 

Toronto, ON  M5J 1T1 

www.denisonmines.com 

PRESS RELEASE

Denison CFO on Temporary Medical Leave of Absence,

Interim CFO Appointed

Toronto, ON – September 1, 2023. Denison Mines Corp. (‘Denison’ or the ‘Company’) (TSX: DML, NYSE

American: DNN) reports that Mac McDonald (CPA), the Company’s Chief Financial Officer, is on a

temporary medical leave of absence. Elizabeth Sidle (C PA, CA), who currently serves as Denison’s Vice

President Finance, has also been appointed Interim Chief Financial Officer.

About Denison

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

region of northern Saskatchewan, Canada. The Compan y has an effective 95% 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 In-Situ Recovery (‘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 lo west 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 (‘EIS’) submitted for regulator and public review

October 2022.

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

Venture, which owns several uranium deposits and the McClean Lake uranium mill, contracted to process

the ore from the Cigar Lake mine under a toll milling agreement, plus a 25.17% interest in the Midwest Main

and Midwest A deposits and a 67.41% interest in the Tthe Heldeth Túé (‘THT’) and Huskie deposits on the

Waterbury Lake property. The Midwest Main, Midwes t A, THT and Huskie deposits are located within 20

kilometres of the McClean Lake mill.

Through its 50% ownership of JCU (Canada) Exploration Co mpany, Ltd (‘JCU’), Denison holds additional

interests in various uranium project joint ventures in Canada, including the Millennium project (JCU,

30.099%), the Kiggavik project (JCU, 33.8118%) and Christie Lake (JCU, 34.4508%).

Denison’s exploration portfolio includes further in terests in properties covering approximately 285,000

hectares in the Athabasca Basin region.

For more information, please contact:

David Cates (416) 979-1991 ext. 362

President and Chief Executive Officer

Elizabeth Sidle (416) 979-1991 ext. 311

Vice President Finance & Interim Chief Financial Officer

Follow Denison on Twitter @DenisonMinesCo

This press release constitutes a "designated news release" for the purposes of the Company's prospectus

supplement dated September 28, 2021 to its short form base shelf prospectus dated September 16, 2021.

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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: expectations with respect to the leave

of absence and Interim CFO appointment; in terpretations, projections and plans with respect to ex ploration, development and

expansion of the Company’s projects; expectations regarding Denison’s joint venture ownership interests; and expectations regarding

the continuity of its agreements with third parties.

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. 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 ma terially from those anticipated in this for ward-

looking information. For a discussion in respect of risks and other factors that could influence forward-looking events, please refer to

the factors discussed in the Company’s Annual Information Form dated March 27, 2023 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.