Cosa plans winter 2026 drilling at JVs with Denison

Executive Summary

• Cosa Resources Corp. announced its winter 2026 drilling plans for its Darby and Murphy Lake North (MLN) projects, which are joint ventures with Denison Mines Corp. in the eastern Athabasca basin, Saskatchewan.
• Drilling at Darby will focus on approximately 2,500 metres to test high-priority targets identified through 2025 core relogging, specifically targeting historical intersections of uranium mineralization and graphitic basement faults.
• Drilling at MLN will comprise approximately 1,200 metres to evaluate the Cyclone trend and an additional parallel trend to the south, with Denison participating in the financing to maintain its 30% interest.

Key Details

• Project Structure: Darby and MLN are 70/30 joint ventures between Cosa Resources (operator) and Denison Mines.
• Location Context: Darby is located 10 km west of Cameco's Cigar Lake mine; MLN is located 3 km east of IsoEnergy's Hurricane deposit.
• Darby Drilling Plan:
  • Approximately 2,500 metres planned for winter 2026.
  • Focus on four initial target areas based on coincident sandstone alteration, anomalous uranium content, and graphitic basement faults.
  • Gamma Trend: Over 4 km of conductive strike length; priority target is follow-up of historical hole DB-17 (108m of anomalous uranium in basal sandstone) and DB-22.
  • Charlie Trend: Priority target is follow-up of hole DB-09, which intersected 115m of elevated to strongly anomalous uranium in the lower sandstone and graphitic faults 30-60m below the unconformity.
  • Delta Trend: Priority target is follow-up of hole DB-27, which intersected 48m of continuously anomalous uranium and 0.13% U3O8 over 0.3m in the basement.
• MLN Drilling Plan:
  • Approximately 1,200 metres planned for winter 2026.
  • Targets a 1,200-metre gap in drilling on the Cyclone trend where a lake prevents summer access.
  • Follow-up on hole MLN25-007, targeting the updip projection of intensely graphitic rocks and faulting to the unconformity, potentially representing an untested trend parallel to Cyclone.
• Timeline and Logistics:
  • Darby: Camp construction nearing completion; drilling expected to commence before the end of January 2026.
  • MLN: Winter trail establishment ongoing; drilling planned to begin in March 2026.
  • Future Plans: Cosa intends to use winter access for summer 2026 testing at Darby. At MLN, winter work supports a property-wide DC resistivity survey planned for spring and a larger summer drilling program.
• Financing: Denison is participating in the financing of the 2026 exploration at MLN to maintain its 30% interest.

Notable Quotes

• Keith Bodnarchuk, President and CEO: "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."
• Andy Carmichael, VP of Exploration: "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-calibre untested target areas near Cigar Lake... 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."