Cosa Begins Summer Drilling Program at Darby Uranium Joint Venture

Cosa Resources Corp., a Canadian uranium exploration company, has announced the commencement of its summer drilling program at the Darby uranium joint venture with Denison Mines Corp. The project, located 10 kilometers west of Cameco's Cigar Lake Mine, is set to explore multiple high-potential targets in the eastern Athabasca Basin.

Cosa, the project operator with a 70% interest, and Denison, holding a 30% stake, are excited to continue their exploration efforts. The summer drilling program, fully funded with $16 million in the treasury, is expected to comprise up to 2,500 meters of drilling. The primary targets are the Gamma and Bravo trends, which show significant geological and geochemical anomalies.

Keith Bodnarchuk, President and CEO of Cosa, expressed enthusiasm about the upcoming drilling season. "Having recently completed an encouraging and productive drilling program at Murphy Lake North, we are excited to be back drilling at the Darby Joint Venture with our partner and largest shareholder, Denison Mines. Darby boasts an exceptional pipeline of high-upside drill targets in proximity to structure, alteration, and historical uranium mineralization."

The drilling at the Gamma trend will follow up on structures, alteration, and anomalous uranium geochemistry intersected during the winter 2026 drill program. At the Bravo trend, the focus will be on weak uranium mineralization proximal to structure and alteration, as well as within a magnetic low trend extending northeast to Cigar Lake.

Andy Carmichael, Vice President of Exploration for Cosa, elaborated on the geological context. "In addition to intersecting basement-hosted uranium mineralization, winter drilling and reinterpretation of historical results at Darby further upgraded multiple trends, notably at Gamma and Bravo. The exceptional geochemical anomalism, numerous intersections of graphitic structure, and significant untested strike length across virtually all major trends at Darby continue to make for an exciting drill season."

At Gamma, the drilling will build on positive results from the winter campaign, where drill hole DB24-41 defined a 100+ meter wide zone hosting graphitic basement faulting associated with 30+ meters of unconformity relief, sandstone and basement alteration, and elevated to anomalous uranium geochemistry in the basal sandstone. Uranium mineralization has been intersected by multiple historical drill holes on the Gamma trend immediately north of the project.

At Bravo, the drilling will target the trend along-strike of encouraging historical results, including graphitic structure, alteration, and uranium mineralization associated with more than 25 meters of unconformity relief. The Bravo trend is interpreted to lie within a magnetic low trend extending through the Cigar Lake uranium mine area to the northeast.

Cosa's portfolio includes roughly 237,000 hectares across multiple underexplored 100% owned and Cosa-operated joint venture projects in the Athabasca Basin region. The company's strategic collaboration with Denison has secured access to several additional highly prospective eastern Athabasca uranium exploration projects. As Denison's largest shareholder, Cosa benefits from Denison's exposure to exploration success and its pipeline of uranium projects.

The company's 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.

The drilling program is expected to further evaluate the potential of the Darby project, which contains multiple prospective conductive trends and several intersections of weak uranium mineralization. Historical drilling indicates that many of these trends are highly prospective for uranium deposits characteristic of the eastern Athabasca Basin, yet most of the strike length has not been effectively evaluated.

With the summer drilling program fully funded and set to commence, Cosa remains focused on advancing the Murphy Lake North and Darby joint ventures with Denison, while also planning for a 100% partner-funded drilling program at its Aurora project.