Mr. Keith Bodnarchuk reports

COSA ANNOUNCES 3,000 METRE SUMMER DRILLING PROGRAM FOR THE MURPHY LAKE NORTH URANIUM PROJECT

Cosa Resources Corp. is planning a 3,000-metre (m) summer drilling program targeting the Hurricane and Cyclone trends on the Murphy Lake North (MLN) project. Murphy Lake North 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.

The company is also pleased to provide an update on its 70-per-cent-owned Darby project, located 10 kilometres (km) west of Cameco's Cigar Lake uranium mine.

Highlights:

• Denison Mines, 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 m in seven to eight drill holes;
• Drilling at the Hurricane trend will follow up significant sandstone alteration and structure intersected during the winter 2025 drill program;
• Drilling at the subparallel Cyclone trend to the south will follow up sandstone alteration and continue evaluation of the eastern extension of over five km of untested conductive strike;
• Relogging historical core at Darby to confirm and identify compelling drill-ready targets developed from desktop interpretations of historical work.

Keith Bodnarchuk, Cosa's president and chief executive officer, commented: "We are excited to be returning to Murphy Lake North for an expanded and fully funded summer drill program, including participation from our joint venture partner and largest shareholder, Denison Mines. Having intersected significant sandstone alteration at both the Hurricane and Cyclone trends during the winter drill program, we are eager to mobilize to site and continue testing targets within a few kilometres of the Hurricane deposit."

Andy Carmichael, Cosa's vice-president of exploration, commented: "Since meeting the key objectives of the winter drilling program, we've been eager to return to Murphy Lake North to follow up the positive winter results at the Hurricane trend. With an increase in exploration along the Larocque Lake corridor post-2018, the parallel Cyclone trend has quickly become one of the most prospective and underexplored conductive trends in the eastern Athabasca. Only four holes have been completed on this trend within MLN and there is ample room for exploration in this exciting area."

Murphy Lake North

Murphy Lake North covers a portion of the Larocque Lake trend and is located 2.7 km 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 km of Hurricane trend basement geology is present within the project (see Cosa's 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 of exploration expenditures at the project during the summer drill program. Denison has indicated that it intends to finance its share of exploration costs that exceed Cosa's sole-finance obligation in order to retain its 30-per-cent interest in the project.

Summer drill program

The summer drill program is planned to comprise over 3,000 metres of drilling at the Hurricane and Cyclone trends. Drilling is anticipated to start at the Hurricane trend with the balance of budgeted meters to be completed where results justify. The company expects to commence drilling in July. Cosa does not anticipate the wildfires in Northern Saskatchewan will delay the start of drilling but continues to monitor the situation, and may adjust its plans in the interest of the health and safety of staff, contractors and the public.

Hurricane trend

Summer drilling is planned to follow up the zone of sandstone alteration and structure intersected by the fourth and final drill hole of the winter exploration program, MLN25-004. Follow-up is expected to involve a series of stepouts along strike to determine if the alteration hosts uranium mineralization.

Cyclone trend

The mineralized Cyclone trend is located south of and oriented subparallel to the Hurricane trend. Since 1996, a series of historical airborne and ground electromagnetic (EM) surveys at MLN mapped several discrete conductors within the broader Cyclone trend. Conductivity at Cyclone is best defined in the central portion of MLN, where 2020 EM surveying completed by Denison mapped a basement EM conductor coincident with a conductive trend identified by 2013 airborne surveying. Summer drilling is planned to evaluate Cyclone at wide spacing for prospective structure and/or alteration.

Darby target generation

The Darby project is a 70/30 Cosa/Denison joint venture operated by Cosa. Located 10 km west of the Cigar Lake mine, Darby is interpreted to contain more than 25 km of prospective conductive strike length. Cosa's reinterpretation of historical data has flagged the 95B, 96D and 4A conductive trends as initial high-priority exploration targets within the Darby project.

Cosa plans to begin the summer exploration season by relogging historical drill core from Darby to confirm its interpretations and refine drill-ready targets in advance of an initial drilling program under development for the winter of 2026. Per the company's news release dated Jan. 14, 2025, Cosa is obligated to sole-finance 100 per cent of the first $5-million of exploration expenditures at Darby by June 30, 2029, to retain its 70-per-cent interest in the Darby project.

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 Mines 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 km 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 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 GPS (Global Positioning System) and determined to be within 20 m 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.