Denison Mines : Investor Update - May 2025

Published: 2025-05-27 14:47:57 ET DML.TO

Published on 05/27/2025 at 14:47

Corporate Update

May 2025

Uranium Development & Exploration

The Athabasca Basin, Northern Saskatchewan

#1 Mining Development Project in the World

Key Investment Highlights(1):

Advanced Athabasca Basin uranium developer with unique asset mix

Three low-cost uranium development projects operated by Denison

Phoenix, Gryphon, and THT/Waterbury all projected within UxC's "First Tier" of global assets

Phoenix combines lowest-cost mining method with Athabasca Basin high-grades

Ranked #1 mining development project globally in 2024 by Mining Journal Intelligence Flagship ISR project with final federal Environmental Impact Statement accepted by CNSC

Technical de-risking completed, with detailed design engineering and long-lead procurement in progress First production targeted by the first half of 2028

Interest in strategic regional asset with McClean Lake mill and mine

Excess licensed milling capacity with approval for expanded tailings management facility Announced 2025 mining restart at McClean Lake North deposit by Orano Canada

High-potential exploration portfolio and interests in key mines / projects operated by "majors"

Large exploration portfolio, including Moon Lake South and Johnston Lake properties

Minority interests in Orano-Denison Midwest Joint Venture & Cameco-JCU's Millennium project

Strong balance sheet with ~CAD$310M in cash, physical uranium and investments(2) Denison's financial and liquid assets on hand, relative to flagship development project initial capex (~$CAD400M)3 is unrivaled and puts the company in an enviable position for project advancement

Focused on the infrastructure-rich Eastern Athabasca Basin in Saskatchewan, Canada

Nuclear renaissance: 30+ nations pledge to triple nuclear energy capacity by 2050

NOTES: (1) See supporting slides for details. (2) For additional details see financial statements and MD&A for the period ended March 31, 2025. (3) Based on Denison's effective 95% ownership. 3

Diversified Athabasca Basin asset base with superior development leverage

95%(1)

effective interest in

Flagship

Wheeler River project

Development-stage project

Largest undeveloped uranium project in the infrastructure rich eastern Athabasca Basin

2023 Phoenix Feasibility Study(2)

Final Environmental Impact Statement accepted by CNSC(3)

22.5%

interest in

Strategic McClean Lake Uranium Mill & Mines

11% of global uranium production processed through mill

Mining restart activities using SABRE mining with production planned for mid 2025

Excess licensed milling capacity

70.55%

interest in

Emerging

Waterbury Lake project

PEA stage development project(4)

Tthe Heldeth Túé ("THT") deposit highlights potential for future development project pipeline

Successful 2023 ISR field test(5)

Participating interests in key development-stage assets operated by uranium "majors"

Includes 22.5% in McClean Lake (Orano), 25.17% in Midwest (Orano), and an effective 15% in Millennium (Cameco) through 50% ownership of JCU(6)

~384,000

hectares of

exploration ground(7)

PHOTO:

Aerial view of Denison's 22.5% owned McClean Lake mill facility

NOTES:

Denison increased its effective interest in Wheeler River as part of the acquisition of 50% of JCU (Canada) Exploration Company, Limited. See Denison's news release dated August 3, 2021.

See the Wheeler River Technical Report titled "NI 43-101 Technical Report on the Wheeler River Project, Athabasca Basin, Saskatchewan, Canada" dated June 23, 2023.

See news release dated November 25, 2024 and Canadian Impact Assessment Registry

Refer to the Waterbury Lake Technical Report titled "Preliminary Economic Assessment for the Tthe Heldeth Túé

(J Zone) Deposit, Waterbury Lake Property, Northern Saskatchewan, Canada" dated October 30, 2020.

See news release dated November 6, 2023.

See news release dated August 3, 2021.

Denison direct land position shown as of March 31, 2025; excludes the land positions held by JCU.

Denison's development portfolio projects:

Multiple assets amongst the lowest all-in cost assets of UxC's First Tier

All-in / Full Costs - USD$/lb U3O8

$70

$60

$50

Sample of Global Production Costs - September 2023 (1)(2)(3)

Planned and Producing Operations (with Mining Method)

"Second Tier"

(up to ~US$48/lb U3O8)

UxC's "First Tier"

(includes lowest-cost projects with full costs up to ~US$33/lb U O )

"Third/Fourth Tier" (up to ~US$92/lb U3O8)

NOTES:

Chart data, including "full costs" and UxC's categorization of production cost "tiers", have been derived from UxC's estimates of

$40

3 8

US$25.47

worldwide production costs from the Uranium Production Cost Study dated September 2023.

ISR

For Phoenix and

$30

$20

$10

US$16.04

ISR

(2023)

US$24.93

ISR

(2020)

(2023)

Kazakhstan

U.S.A.

Gryphon, see the Wheeler River Technical Report titled "NI 43-101 Technical Report on the Wheeler River Project, Athabasca Basin, Saskatchewan, Canada" dated June 23, 2023.

For THT/Waterbury, refer to the Waterbury Lake Technical Report titled "Preliminary Economic Assessment for the Tthe Heldeth Túé (THT) (J Zone) Deposit, Waterbury Lake Property, Northern Saskatchewan, Canada" dated October 30, 2020.

Disclaimer

Denison Mines Corp. published this content on May 27, 2025, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on May 27, 2025 at 18:26 UTC.