Cosa commences ambient noise tomography survey at Astro uranium project, Saskatchewan

Vancouver, British Columbia--(Newsfile Corp. - June 26, 2026) - Cosa Resources Corp. (TSXV: COSA) (OTCQB: COSAF) (FSE: SSKU) (" Cosa " or the " Company ") is pleased to announce the commencement of an ambient noise tomography (" ANT ") survey at the Astro project (" Astro " or the " 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 funded by Cosa's partner, Global Uranium Corporation  (CSE: GURN) (OTCQB: GURFF) (FSE: Q3J)  (" Global" ) per the option agreement (the " Agreement ") announced by the Company on April 9 th , 2025.

Global has the right to earn up to an 80% interest in the Astro project by sole-funding $9.5 million in exploration expenditures and completing cash and share payments. Highlights ANT survey and supporting work are 100% funded 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 surveying and diamond drilling Andy Carmichael, VP 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 (" CAUR ") 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 (Figure 2), 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-funded 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 (Figure 2). 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 was 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. Figure 1 - Cosa's Eastern Athabasca Uranium Projects To view an enhanced version of this graphic, please visit: https://images.newsfilecorp.com/files/9865/302885_b1676fc8e4a5aa95_003full.jpg Figure 2 - Astro Project with Basement Conductivity To view an enhanced version of this graphic, please visit: https://images.newsfilecorp.com/files/9865/302885_b1676fc8e4a5aa95_004full.jpg About Cosa Resources Corp. Cosa Resources is a Canadian uranium exploration company operating in northern Saskatchewan. The portfolio comprises roughly 237,000 ha across multiple underexplored 100% 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 Mines (TSX: DML) (NYSE American: DNN) 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 track 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. About Global Uranium Energy Corp. Global Uranium Corp. focuses on exploring and developing uranium assets primarily in North America.

The Company currently holds key uranium projects: the Wing Lake Property in the Mudjatik Domain of Northern Saskatchewan, Canada; the Northwest Athabasca Joint Venture with Forum Energy Metals Corp. and NexGen Energy Ltd. in the Northwest Athabasca region of Saskatchewan, Canada; and the Great Divide Basin District Projects, the Gas Hills District Projects, and the Copper Mountain District Projects in Wyoming, USA. 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, P.Geo., 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. Contact Keith Bodnarchuk, President and CEO info@cosaresources.ca +1 888-899-2672 (COSA) Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Cautionary Statements This press release contains forward-looking information within the meaning of Canadian securities laws (collectively "forward-looking statements"). Forward-looking statements are typically identified by words such as: believe, expect, anticipate, intend, estimate, plans, postulate and similar expressions, or are those, which, by their nature, refer to future events. All statements that are not statements of historical fact are forward-looking statements.

These forward-looking statements or information may relate to anticipated exploration, development and/or expansion activities, including exploration of the Company's current Projects; the collaboration with Denison, including the Joint Venture, and the anticipated benefits thereof; and the outlook regarding Cosa's business plans and objectives. Such forward-looking information and statements are based on numerous assumptions, including among others, that the results of planned exploration activities are as anticipated, the cost of planned exploration activities are as anticipated, that general business and economic conditions will not change in a material adverse manner, that financing will be available if and when needed and on reasonable terms, that third party contractors, equipment and supplies and governmental and other approvals required to conduct Cosa's planned exploration activities will be available on reasonable terms and in a timely manner. Although the assumptions made by Cosa in providing forward-looking information or making forward-looking statements are considered reasonable by management at the time, there can be no assurance that such assumptions will prove to be accurate.

By their nature, forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements, or other future events, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such factors and risks include, among others: Cosa may require additional financing from time to time in order to continue its operations which may not be available when needed or on acceptable terms and conditions acceptable; Cosa may not be able to maintain compliance with its contractual obligations with third parties; Cosa may not be able to maintain compliance with extensive government regulation applicable to its operations; domestic and foreign laws and regulations could adversely affect Cosa's business and results of operations; the stock markets have experienced volatility that often has been unrelated to the performance of companies and these fluctuations may adversely affect the price of Cosa's securities, regardless of its operating performance; the ongoing military conflict in Ukraine, and other risk factors set out in Cosa's public disclosure documents. The forward-looking information contained in this news release represents the expectations of Cosa as of the date of this news release and, accordingly, is subject to change after such date.

Readers should not place undue importance on forward-looking information and should not rely upon this information as of any other date. Cosa does not undertake any obligation to update these forward-looking statements in the event that management's beliefs, estimates or opinions, or other factors, should change. To view the source version of this press release, please visit https://www.newsfilecorp.com/release/302885 Newsfile Corp. June 26, 2026 - 5:00 AM PDT News by QuoteMedia www.quotemedia.com