Cosa Announces Winter 2026 Drilling Plans for Joint Ventures with Denison Mines

Vancouver, British Columbia--(Newsfile Corp. - January 21, 2026) - Cosa Resources Corp. (TSXV: COSA) (OTCQB: COSAF) (FSE: SSKU) ("Cosa" or the "Company") is pleased to announce drilling plans for the Company's Darby and Murphy Lake North ("MLN") projects (Figure 1). Darby and MLN are joint ventures (the "Joint Venture") between Cosa and Denison Mines Corp. (TSX: DML) (NYSE American: DNN) ("Denison") and are located 10 kilometres west of Cameco's Cigar Lake Mine and three kilometres east of IsoEnergy's Hurricane Deposit, respectively, in the eastern Athabasca Basin, Saskatchewan. Cosa is the operator of both projects and holds a 70% interest with Denison holding a 30% interest in each.

Highlights

• Drilling at Darby will directly follow up compelling historical results including anomalous uranium content in the sandstone and weak uranium mineralization in the basement

• Drilling at MLN will further evaluate the kilometre-scale structure and alteration zone at the Cyclone trend and an additional parallel trend to the south

• Denison participating in funding 2026 exploration at MLN to maintain its 30% interest

Keith Bodnarchuk, President and CEO, commented: "Identification of additional drill ready targets proximal to historical intersections of uranium mineralization and under modest sandstone cover has added to our excitement to commence drilling at Darby. With support and participation from Denison, our Joint Venture partner and largest shareholder, we are fully funded and prepared for an exciting year of exploration at both Darby and Murphy Lake North. We thank Denison for their continued guidance and commitment to working towards exploration success at these projects. Camp construction is well underway, and we expect drilling to commence at Darby next week."

Andy Carmichael, Vice President of Exploration, commented: "Retention of high-quality data by Denison combined with the experience gained over the last 15 years has allowed us to identify what may be some of the last remaining high-caliber untested target areas near Cigar Lake. Darby hosts five historical intersections of mineralization proximal to untested structures across multiple trends. Our initial target areas have coincident untested structures, alteration, and anomalous uranium content in the lower sandstone. At MLN, we are eager to continue testing large gaps in strike where compelling structure and alteration have been intersected by widely spaced drilling on the Cyclone trend. Evaluation of an additional trend south of Cyclone is also a priority objective for this winter. Our decision to prioritize targets under frozen lakes, combined with a property-wide DC-Resistivity survey planned for the spring, is aimed at identifying the most prospective targets for an expanded follow up campaign in the summer."