Cosa Announces Largest Drill Program to Date at Murphy Lake North with Participation from Denison Mines

Vancouver, British Columbia, May 28 2026 – Cosa Resources Corp. (TSX-V: COSA) (OTCQB: COSAF) (FSE: SSKU) (“Cosa” or the “Company”) is pleased to announce summer plans for the largest drill program to date at the Company’s Murphy Lake North (“MLN”) project. Drilling is set to commence in mid-June and will follow up on uranium mineralization intersected in winter 2026. Muphy Lake North 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, in the eastern Athabasca Basin, Saskatchewan. Cosa is the project operator and holds a 70% interest with Denison holding a 30% interest.