Cosa commences largest drill program at Murphy Lake North with Denison

Vancouver, British Columbia--(Newsfile Corp. - June 18, 2026) - Cosa Resources Corp. (TSXV: COSA) (OTCQB: COSAF) (FSE: SSKU) (" Cosa " or the " Company ") is pleased to announce drilling has commenced 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.  (TSX: DML) (NYSE American: DNN) (" Denison ") 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 Drilling will evaluate potential extensions of the Cyclone uranium mineralization intersected during the winter program which is open along strike for 600 metres in both directions and located only 265 metres below surface Drilling to comprise approximately 6,000 metres in 15 drill holes and represents the largest drill program in the history of the Company Denison participating in funding 2026 exploration at MLN to maintain its 30% interest Keith Bodnarchuk, President and CEO, commented: " We have officially kicked off our largest and most exciting drill program in Cosa's history, with a strong inventory of drill targets designed to follow up on uranium mineralization intersected during the winter drill program. We thank our Joint Venture partner and largest shareholder, Denison Mines, for their continued support and encouragement. I would also like to wish Andy Carmichael and the entire complement of Cosa's dedicated staff and contractors a safe and successful drill program, and we eagerly await the opportunity to update the market on this summers' progress .

" Summer Drilling Summer drilling at Murphy Lake North is expected to comprise approximately 15 drill holes totaling 6,000 metres. Drilling will focus on following up uranium mineralization intersected during winter 2026 which is o