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

• Announcement Date: May 28, 2026
• Headline: Cosa Announces Largest Drill Program to Date at Murphy Lake North with Participation from Denison Mines
• Core Event: Commencement of a ~6,000-metre summer drill program across 15 holes at the Murphy Lake North (MLN) project.
• Assay Context: Results confirm Winter 2026 drilling success, specifically hole MLN26-013 with 5.0m @ 0.55% U3O8 including high-grade intervals up to 1.70% U3O8.
• Joint Venture: Denison Mines Corp. participates in funding to maintain its 30% interest; Cosa retains 70% operatorship.
• Target Focus: Step-out tests of Cyclone mineralization approx 265 metres below surface; follow up on uranium mineralization open along strike for 600 metres.
• Strategic Alignment: Confirms the drill program previously hinted at in the May 26, 2026 assay release ("We expect to update... with plans").

• Catalyst Validation: The news validates the material positive catalyst from two days prior (May 26 assay results). It transitions the company from discovery confirmation to execution.
• Funding Security: Denison Mines participation in funding reduces immediate dilution risk for Cosa shareholders regarding exploration costs, as JV partners typically cover their proportional share of expenditures.
• Program Scale: The "largest drill program to date" (6,000m) signals management confidence and capital commitment, which is positive but largely priced in following the assay confirmation.
• Expectation Management: Since the May 26 release explicitly stated plans for a large summer program were expected, this announcement fulfills prior guidance rather than introducing unexpected upside.
• Market Reaction: Likely viewed as Routine - Positive; it solidifies the thesis but does not introduce new valuation drivers beyond what the assay results provided.

• Company: Cosa Resources Corp. (TSXV: COSA).
• Flagship Project: Murphy Lake North (MLN) Joint Venture with Denison Mines.
• Location: Eastern Athabasca Basin, Saskatchewan (3 km east of IsoEnergy's Hurricane deposit).
• Strategy: Discovery and development of high-grade unconformity-hosted uranium deposits using joint-venture partnerships.
• Other Projects: Darby JV (Denison), Packrat JV (Denison), Ursa, Orion, Orbit (100% owned), Aurora (Option to Traction Uranium), Astro (Option to Global Uranium).
• Management Track Record: Team includes members with experience in the Hurricane discovery and other Athabasca projects.