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 70/30 joint ventures with Denison Mines Corp. located in the eastern Athabasca basin, Saskatchewan.
• Drilling at Darby will involve approximately 2,500 metres to test high-priority targets on the Gamma, Charlie, and Delta trends, focusing on historical intersections of uranium mineralization and graphitic basement faults.
• Drilling at MLN will comprise approximately 1,200 metres to follow up on summer 2025 results at the Cyclone trend and evaluate an untested parallel trend to the south, with Denison participating in the financing to maintain its 30% interest.

Key Details

• Project Structure: Darby and MLN are joint ventures between Cosa Resources (70% operator) and Denison Mines (30%).
• Location: Both projects are located in the eastern Athabasca basin, Saskatchewan; Darby is 10 km west of Cameco's Cigar Lake mine, and MLN is 3 km east of IsoEnergy's Hurricane deposit.
• Darby Drilling Plan:
  • Total planned drilling: Approximately 2,500 metres in winter 2026.
  • Objective: Test high-priority targets identified by 2025 core relogging and reinterpretation, specifically immediate vicinities of drill holes intersecting sandstone alteration and anomalous uranium content proximal to graphitic basement faults.
  • Target Areas: Up to four initial target areas across the Gamma, Charlie, and Delta trends.
  • Gamma Trend: Focus on follow-up of historical hole DB-17 (108m of anomalous uranium in basal sandstone) and DB-22.
  • Charlie Trend: Focus on follow-up of hole DB-09 (115m of anomalous uranium, including 42m continuously anomalous).
  • Delta Trend: Focus on follow-up of hole DB-27 (48m continuously anomalous uranium, 0.13% U3O8 over 0.3m in basement).
• MLN Drilling Plan:
  • Total planned drilling: Approximately 1,200 metres.
  • Objective: Follow up summer 2025 results at the Cyclone trend (2km strike length of structure/alteration) and evaluate a 1,200m gap in drilling where a lake prevents summer access.
  • Additional Target: Follow up intensely graphitic rocks and faulting intersected in MLN25-007, targeting the updip projection to the unconformity, potentially representing an untested trend parallel to Cyclone.
  • Financing: Denison is participating in the financing of the 2026 exploration at MLN to maintain its 30% interest.
• Timeline and Logistics:
  • Darby: Camp construction nearing completion; drilling expected to begin before the end of January 2026.
  • MLN: Winter trail establishment ongoing; drilling planned to begin in March 2026.
  • Future Plans: Use of winter access trails for summer 2026 testing at Darby; property-wide DC resistivity surveying planned for spring at MLN to support a larger summer drilling program.

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."