Cosa drills Murphy Lake North uranium joint venture with Denison Mines

Vancouver, British Columbia--(Newsfile Corp. - September 14, 2026) - Cosa Resources Corp. (TSXV: COSA) (OTCQB: COSAF) (FSE: SSKU) (" Cosa " or the " Company ") is pleased to announce results of the summer drilling program at the Company's Murphy Lake North (" MLN ") project (Figure 1). MLN is a joint venture (the " Joint Venture ") between Cosa and Denison Mines Corp. (" Denison ") (TSX: DML) (NYSE American: DNN) and is located three kilometres east of IsoEnergy's Hurricane Deposit. Cosa is the project operator and holds a 70% interest with Denison holding a 30% interest.

Highlights

Multiple zones of structurally controlled alteration and elevated radioactivity remain open along strike for several hundred meters and on multiple sections

Drilling evaluated multiple structures over 650 metres of strike length with all 13 drill holes intersecting strong structure and/or alteration

Summer 2026 drilling prioritized unconformity targets with significant room for basement-hosted mineralization remaining

With $16 million in the treasury, Cosa remains fully funded for a significant follow up drilling campaign

Keith Bodnarchuk, President and CEO, commented: "We remain very encouraged by the potential at Murphy Lake North. Having previously confirmed the trend hosts uranium mineralization, summer drilling has significantly advanced our understanding of the geology in the immediate area. Highly prospective drill results paired with an abundance of open space emphasize our excitement and commitment to fully evaluating the Cyclone trend and multiple other strong target areas on the Project. With drilling expected to commence at both the Darby joint venture with Denison, and the Aurora project, we expect steady news flow for the remainder of 2026, followed by a return to MLN in early 2027. With $16 million in the treasury and support from our Joint Venture partner and