Mr. Keith Bodnarchuk reports

COSA COMMENCES PARTNER FUNDED AMBIENT NOISE TOMOGRAPHY SURVEY AT THE ASTRO URANIUM PROJECT, ATHABASCA BASIN, SASKATCHEWAN

Cosa Resources Corp. has commenced an ambient noise tomography (ANT) survey at the Astro project. Astro is located in the eastern Athabasca basin, approximately 28 kilometres west of Cameco's McArthur River uranium mine. The survey and supporting work are fully financed by Cosa's partner, Global Uranium Corp., per the option agreement announced by the company on April 9, 2025. Global has the right to earn up to an 80-per-cent interest in the Astro project by sole financing $9.5-million in exploration expenditures and completing cash and share payments.

Highlights:

• ANT survey and supporting work are 100 per cent financed by Global;
• Survey will identify seismic anomalies potentially attributable to prospective geological features, including unconformity offsets and zones of strong hydrothermal alteration;
• Results of the survey to guide proposed follow-up ground EM (electromagnetic) surveying and diamond drilling.

Andy Carmichael, vice-president, exploration, of Cosa, commented: "Building on the success of the 2025 airborne program, which defined over 25 kilometres of prospective conductive strike, a significant partner-funded ANT program at Astro has potential to generate compelling drill targets in an area that is entirely untested for the presence of a Tier 1 eastern Athabasca uranium deposit. We look forward to the results of the ANT survey and ultimately advancing the project towards a potential inaugural drill program in 2027."

ANT survey

Surveying will be completed by CAUR Technologies of Quebec, Canada. CAUR's objective is to deliver high-resolution shear wave velocity models that will refine geological interpretations and guide drill targeting by delineating lithological contrasts, structural features and alteration zones within the lower Athabasca sandstone and upper basement rocks. The area of interest for the survey is the AS-1 target area, which covers a significant portion of a 25-kilometre-long, east-northeast-trending conductive corridor defined by a project-wide airborne survey completed by Cosa in 2025. East-northeast-trending conductive corridors are high-priority exploration targets in the Athabasca basin as they are known to host Tier 1 deposits like McArthur River and Cigar Lake. The survey design will deploy 300 seismic sensors and is expected to take two months to complete.

Next steps

Results of the survey will be used to identify and prioritize prospective strike for additional work. Follow-up partner-financed work may include ground EM surveying in Q1 2027 to define conductive drill targets, with an inaugural drill program to follow.

About Astro

The Astro project is located roughly 28 kilometres west of Cameco's McArthur River mine, the world's largest high-grade uranium mine, and approximately 10 kilometres west of Canalaska Uranium Ltd.'s Pike zone, which boasts world-class intersections. Only one historical drill hole, EK-01, has been completed on the project. EK-01 failed to explain the strong conductive response it was targeting, suggesting the hole was not ideally located. Historical drill log notes favourable features in the sandstone, including a brecciated and silicified interval in the upper portion, decametre-scale intervals of illite-dominated clay mineralogy throughout, and moderately bleached and slightly friable intervals in the lower 150 metres. All features are commonly associated with unconformity-related uranium deposits of the Athabasca basin. Roughly 11 kilometres to the southwest of EK-01 and within 700 metres of the Astro project, strongly anomalous uranium geochemistry and pervasive hydrothermal alteration were intersected in the lower to medial sandstone of historical drill holes CR-06 and CR-15. Drilling completed by Cosa in 2024 failed to explain the source of the geochemical anomaly; however, ground-based EM work completed by Cosa indicates that the targeted conductor likely trends onto the Astro project. Notably, the project is unexplored for the extension of regional structures related to both the McArthur River and Fox Lake uranium deposits, located roughly 28 and 17 kilometres east of Astro, respectively. Cosa and Global Uranium will execute a work plan designed to rapidly and efficiently canvas much of the Astro project for identification of the most compelling drill targets. The depth to the unconformity at Astro is estimated to be between 850 and 975 metres.

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, 2025, the company entered a transformative strategic collaboration with Denison Mines that has secured access to 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.

The company's primary focus through the remainder of 2026 will be drilling at the Murphy Lake North and Darby projects in the eastern Athabasca basin. Drilling at Murphy Lake North will follow up uranium mineralization within an extensive zone of strong structure and hydrothermal alteration at the Cyclone trend. Drilling at Darby will follow up on intersections of anomalous geochemistry, structure and zones of hydrothermal alteration from both winter 2026 drilling and historical drilling.

Cosa's award-winning management team has a record of success in Saskatchewan. In 2022, members of the Cosa team were awarded the AME Colin Spence Award for the discovery of the Hurricane uranium deposit. Cosa personnel led teams or had integral roles in the discovery of Denison's Gryphon deposit and held key roles in the founding of both NexGen and IsoEnergy.

Technical disclosure

Historical exploration results disclosed in this news release were sourced from the Saskatchewan Mineral Assessment Database (SMAD). These results have not been verified by the qualified person except as noted below and are relied upon for qualitative assessment of the project only. At present, the company does not intend to complete additional verification of historical results. SMAD sources for Astro include 74-0015, 74H13-0009, 74H11-0113, 74G16-0010, 74H13-0015 and 74H13-0016.

Verification of historical drilling results included confirming the approximate collar location of historical drill hole EK-01 from air photos. Verification of geophysical results is limited to verification of selected local grid locations for SMAD files 74-0015 and 74H13-0009 and qualitatively assessing whether drilling results from survey areas or along the interpreted strike can reasonably explain historical geophysical interpretations.

Qualified person

The company's disclosure of technical or scientific information in this press 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.