Mr. Keith Bodnarchuk reports

COSA COMMENCES 3,000 METRE SUMMER DRILLING PROGRAM AT THE MURPHY LAKE NORTH URANIUM PROJECT

Cosa Resources Corp. has commenced a 3,000-metre summer drilling program targeting the Hurricane and Cyclone trends on the Murphy Lake North (MLN) project. MLN is a joint venture between Cosa and Denison Mines Corp., and is located in the eastern Athabasca basin in Saskatchewan. Cosa is the project operator and holds a 70-per-cent interest, with Denison holding a 30-per-cent interest.

Highlights:

• Denison, Cosa's joint venture partner and largest shareholder, has indicated it will finance its portion to retain a 30-per-cent interest in the Murphy Lake North joint venture;
• Largest drill program to date on the project with a planned 3,000 metres in up to eight drill holes;
• Drilling is planned to follow up significant sandstone alteration intersected by winter drilling at the Hurricane trend and to complete reconnaissance testing of the parallel Cyclone trend.

Keith Bodnarchuk, president and chief executive officer of Cosa, commented: "This is the most exciting time of the year for Cosa as drilling has officially begun. Thanks to our VP, exploration, Andy Carmichael, and the rest of our technical team and contractors for ensuring a safe and timely start to this summer drilling program. We are eager to continue testing promising targets at the Hurricane and Cyclone trends following the encouraging results of our inaugural winter program earlier this year. With positive sentiment returning to the uranium sector and the continued support of our joint venture partner and largest shareholder, Denison, we are well positioned to advance the Murphy Lake North project toward its full potential."

Murphy Lake North

Murphy Lake North covers a portion of the Larocque Lake trend and is located 2.7 kilometres east of the Hurricane deposit. Hurricane is the world's highest-grade indicated uranium resource, and was discovered and delineated for IsoEnergy Ltd. by current members of Cosa's management, board of directors and advisers from 2018 through 2022. The Larocque Lake trend also hosts the high-grade Larocque Lake zone, Yelka prospect and Alligator Lake zone.

Initial drilling in winter, 2025, confirmed that up to two kilometres of Hurricane trend basement geology is present within the project (see Cosa news release dated March 20, 2025). While testing the southern portion of the Hurricane trend, the fourth and final drill hole of the program intersected a broad zone of alteration and structure in the lower sandstone that is open along strike in both directions.

Per the completed acquisition agreement between Cosa and Denison (see Cosa's news release dated Jan. 14, 2025), Cosa expects to meet its obligation to sole-finance $1.5-million (Canadian) of exploration expenditures at the project during the summer drill program. Denison has indicated that it intends to fund its share of exploration costs that exceed Cosa's sole-financing obligation in order to retain its 30-per-cent interest in the project.

For details of Cosa's planned drill program and target areas, see the company's news release dated June 17, 2025.

About Cosa Resources Corp.

Cosa Resources is a Canadian uranium exploration company operating in Northern Saskatchewan. The portfolio comprises roughly 237,000 hectares across multiple underexplored 100-per-cent-owned-and-Cosa-operated joint venture projects in the Athabasca basin region, the majority of which reside within or adjacent to established uranium corridors.

In January of 2025, the company entered a transformative strategic collaboration with Denison that has secured Cosa access into several additional highly prospective eastern Athabasca uranium exploration projects. As Cosa's largest shareholder, Denison gains exposure to Cosa's potential for exploration success and its pipeline of uranium projects.

Cosa's award-winning management team has a long record of success in Saskatchewan. In 2022, members of the Cosa team were awarded the AME Colin Spence Award for their previous involvement in discovering IsoEnergy's Hurricane deposit. Prior to Hurricane, Cosa personnel led teams or had integral roles in the discovery of Denison's Gryphon deposit and 92 Energy's GMZ zone, and held key roles in the founding of both NexGen and IsoEnergy.

The company's core focus throughout 2025 is drilling at the Murphy Lake North joint venture. Murphy Lake North is a 70/30 joint venture between Cosa and Denison, respectively, and is located at the northern end of the Larocque Lake trend. The project is within three kilometres of and on trend with the Hurricane deposit. Initial drilling completed by Cosa during winter, 2025, intersected broad zones of hydrothermal alteration of the sandstone, associated with prospective basement structures interpreted as the strike extension of those controlling the Hurricane deposit. An expanded follow-up campaign is currently in planning for the summer season.

Technical disclosure

Historical drilling and geophysical results for Murphy Lake North and adjacent projects were sourced from the Saskatchewan Mineral Assessment Database (SMAD). SMAD sources for the Murphy Lake North project include file Nos. 74I-0060, 74I09-0057, 74I09-0064, 74I09-0066, 74I09-0077, 74I09-0098 and MAW00510. Data and reports related to the 2020 ground EM (electromagnetic) survey completed by Denison are not presently available via SMAD and were supplied to Cosa by Denison.

SMAD sources for drilling and geophysical results proximal to Murphy Lake North include 64L05-0161, 64L05-0180, 74I-0066, 74I-0067, 74I01-0114, 74I08-0056, 74I09-0053, 74I09-0061, 74I09-0064, 74I09-0071, 74I09-0079, 74I09-0087, 74I09-0088, 74I09-0090, 74I09-0091, 74I09-0092, MAW01939, MAW02327, MAW02599 and MAW02395.

Drill hole collar locations for Murphy Lake North and relevant along-strike drill holes were verified from air photos. The collar locations of Murphy Lake North drill holes CRK-144 and CRK-145 were verified on the ground using a hand-held Global Positioning System (GPS) and determined to be within 20 metres of the locations derived from air photos. Segments of drill core from CRK-143 and CRK-144 were reviewed in the field; further review was hampered by the deteriorated condition of core boxes.

Verification of historical geophysical results included confirming the locations of geophysical survey grids from air photos, compiling data from geophysical surveys completed post-2000, engaging a consultant to reinterpret historical geophysical surveys completed inside MLN and comparing with historical interpretations, and evaluating whether interpreted geophysical results could be reasonably explained by historical drilling results.

Qualified person

The company's disclosure of technical or scientific information in this news release has been reviewed and approved by Andy Carmichael, PGeo, vice-president, exploration, for Cosa. Mr. Carmichael is a qualified person as defined under the terms of National Instrument 43-101. This news release refers to neighbouring properties in which the company has no interest. Mineralization on those neighbouring properties does not necessarily indicate mineralization on the company's properties.

We seek Safe Harbor.