COSA.V · 2025-08-25 12:00:00

Cosa Identifies Two Kilometres of Strong Sandstone Alteration and Graphitic Faulting at the Cyclone Trend on the Murphy Lake North Uranium Project

Exploration Programs

Cosa Identifies Two Kilometres of Strong

Sandstone Alteration and Graphitic Faulting at

the Cyclone Trend on the Murphy Lake North

Uranium Project

Vancouver, British Columbia--(Newsfile Corp. - August 25, 2025) -

Cosa Resources Corp.

(TSXV:

COSA) (OTCQB: COSAF) (FSE: SSKU)

Cosa

" or the "

Company

") is pleased to report summer

drilling has successfully identified two kilometres of highly prospective strike length characterized by

strong sandstone alteration and graphitic faulting at the Cyclone Trend on the Murphy Lake North Project

MLN

" or the "

Project

"). MLN is a joint venture (the "

Joint Venture

") between Cosa and Denison

Mines Corp.

(TSX: DML) (NYSE American: DNN

) ("

Denison

") and is located in the eastern

Athabasca Basin, Saskatchewan. Cosa is the project operator and holds a 70% interest with Denison

holding a 30% interest.

Highlights

Two kilometres of strong sandstone structure and alteration identified at the Cyclone trend

underlain by large scale graphitic faulting

Up to 30 metres of unconformity relief identified at Cyclone

Alteration and structure at Cyclone remain open in both directions and follow up drill targets exist

along multiple trends

Cosa has met its sole-fund obligation and now owns an irrevocable 70% interest in Murphy Lake

North

Keith Bodnarchuk, President and CEO of Cosa, commented:

"The results of the Murphy Lake North

summer drill program, specifically those at the Cyclone trend, are the most significant to date for

Cosa, and further support our thesis that ample search space remains for the next uranium discovery

in the infrastructure rich eastern Athabasca Basin. I want to thank Andy Carmichael and our field team

for executing a successful program in a safe and timely manner. We would also like to thank our

largest shareholder and Joint Venture partner, Denison Mines, for their continued support and

enthusiasm for exploration at Murphy Lake North."

Andy Carmichael, VP Exploration of Cosa, commented:

"Summer drilling at Cyclone identified over

two kilometres of highly prospective strike length and potentially identified an additional unexplored

parallel trend to the south. The intensity and continuity of sandstone alteration and structure, both

vertically and along strike, is an encouraging indicator of the trend's prospectivity. Basement

structures intersected two kilometres apart are textbook examples of major graphitic faults critical to

the formation of eastern Athabasca uranium deposits. With an average depth to the unconformity of

roughly 250 metres, the Cyclone trend is incredibly well situated for the discovery of relatively shallow

mineralization. Cosa and Denison have again elected to leave much of the drill equipment on site to

minimize the time and cost to resume work in 2026."

Chad Sorba, VP Technical Services & Project Evaluation of Denison and Technical Advisor to Cosa,

commented:

"We congratulate Cosa for completing a safe and successful drill program on behalf of

the Murphy Lake North Joint Venture. The structure and alteration observed at the Cyclone trend are

encouraging and could represent early indicators of an eastern Athabasca uranium bearing trend.

These initial results illustrate the potential benefits of Denison's strategy to advance a portion of our

large exploration project portfolio through joint ventures with capable and motivated partners. We are

excited to continue working with Cosa to plan and execute a follow up drill program at Murphy Lake

North in early 2026."

Drilling Program

Summer drilling at Murphy Lake North totaled 3,323 metres in eight holes completed as initial

reconnaissance of the Cyclone trend and to follow up winter 2025 drilling results on the Hurricane trend

(Figure 2). Positive results and greater exploration space led to a focus on Cyclone during the program.

Cyclone Trend Summary

Cyclone was drilled on four sections over 2.4 kilometres of strike length. Six of seven drill holes

intersected positive results; the seventh is interpreted as an overshot of the optimal target. Drilling

identified geology considered highly prospective for an eastern Athabasca style uranium deposit

including significant unconformity relief associated with major structures hosted within graphitic

basement rocks. Faulting controls broad zones of alteration in the sandstone and basement which are

comparable to those associated with the region's uranium deposits. Weakly elevated radioactivity was

intersected at the unconformity and in the basement and is typically associated with hematite and/or clay

alteration.

Results at Cyclone are exemplified by Section 2600E where the broadest and strongest alteration and

structure were intersected (Figure 3). Three drill holes on 2600E define a significant graphitic basement

fault zone within a broader package of graphitic rocks associated with 30 metres of unconformity relief

(Figures 3 and 4). Basement-rooted faulting is interpreted to extend through the entire 220 metre

thickness of the sandstone as faulting is evident beginning at the top of bedrock. These vertically

extensive structures control broad zones of hydrothermal alteration. In MLN25-010, nearly half of the

sandstone is structured including a 70-metre interval with strong fracturing, faulting, fault gouges,

increased clay content and sections of near-massive clay, rotated sandstone bedding, strong bleaching,

desilicification, and decimeter-scale zones of increased radioactivity (Figures 3 and 5).

The continuity and intensity of alteration and structure are considered highly encouraging. The Cyclone

alteration zone remains open in multiple directions and includes untested sections of up to 1.2

kilometres strike length (Figure 2). With continued support from its Joint Venture partner and largest

shareholder Denison Mines, Cosa will use pending geochemical results to guide follow up drilling in

early 2026.

Hurricane Trend Summary

MLN25-006 was completed as a 400 metre step out from winter drill hole MLN25-004 (Figure 2).

MLN25-004 intersected a broad zone of alteration and structure in the lower sandstone (see Cosa's

News Release dated 20 March 2025). In MLN25-006, the lower 93 metres of sandstone displays strong

bleaching, local clay alteration, and structure underlain by fault-controlled clay and chlorite alteration in

the upper basement. MLN25-006 intersected improved alteration compared to MLN25-004 and

additional follow-up to the east may be warranted pending geochemical results.

Figure 1 - Cosa's Eastern Athabasca Uranium Projects with Joint Venture Projects