Cosa starts drilling at Darby with Denison

Executive Summary

• Cosa Resources Corp. has commenced its Winter 2026 drilling campaign at its Darby project, with drilling at the Murphy Lake North (MLN) project to follow.
• Both projects are 70/30 joint ventures operated by Cosa with Denison Mines Corp., located in the eastern Athabasca basin, Saskatchewan.
• The campaign aims to test priority targets identified through 2025 core relogging and reinterpretation, focusing on zones of coincident sandstone alteration and anomalous uranium content near graphitic basement faults.

Key Details

• Drilling Volume and Scope:
  • Darby Project: Approximately 2,500 metres planned for Winter 2026.
  • Murphy Lake North (MLN): Approximately 1,200 metres planned to follow Darby.
• Darby Project Specifics:
  • Targets are based on 2025 core relogging and reinterpretation.
  • Focus areas are immediate vicinities of drill holes intersecting zones of coincident sandstone alteration and anomalous uranium content proximal to significant graphitic basement faults.
  • Up to four initial target areas will be evaluated.
  • Darby was last drilled in 2009; historical drilling shows multiple prospective conductive trends and weak uranium mineralization.
• Murphy Lake North (MLN) Specifics:
  • Follows up on Summer 2025 results at the Cyclone trend, where broad zones of structure and alteration were intersected over a two-kilometre strike length.
  • Drilling will target a 1,200-metre gap in existing drilling caused by a lake preventing summer access.
  • Will test a potential trend parallel to and approximately 100 metres south of Cyclone, interpreted from intensely graphitic rocks and faulting in the basement of hole MLN25-007.
• Joint Venture Structure:
  • Cosa holds a 70% interest and acts as operator.
  • Denison Mines Corp. holds a 30% interest.
  • Projects are located in the eastern Athabasca basin, near Cameco's Cigar Lake mine and IsoEnergy's Hurricane deposit.
• Technical Verification:
  • Historical drilling and geophysical data sourced from the Saskatchewan Mineral Assessment Database (SMAD) and confidential data supplied by Denison.
  • Verification included confirming drill hole collar locations via air photos and handheld GPS, and relogging basement/lower sandstone sections in 2024/2025.
  • Qualified Person: Andy Carmichael, PGeo, Vice-President, Exploration.

Notable Quotes

• No direct quotes from management were included in the provided text.