Fortuna Mining's Diamba Sud at 1.25 Moz Au indicated

Executive Summary

• Fortuna Mining Corp. released an updated mineral resource estimate for its Diamba Sud gold project in Senegal, effective January 16, 2026.
• The update reflects a 73% increase in Indicated Mineral Resources, totaling 1.25 million ounces of gold, driven by infill and expansion drilling as well as an updated gold price assumption.
• The company is advancing a feasibility study for the project, targeting completion by the end of Q2 2026 to support a potential construction decision in mid-2026.

Key Details

• Indicated Mineral Resources: 26.0 million tonnes at an average grade of 1.50 g/t Au, containing 1,254,000 ounces of gold.
• Inferred Mineral Resources: 2.1 million tonnes at an average grade of 1.13 g/t Au, containing 77,000 ounces of gold.
• Southern Arc Deposit: First-time estimation of indicated resources for this deposit, comprising 6.0 million tonnes at 1.91 g/t Au, containing 367,000 ounces of gold; identified as the largest gold deposit discovered to date at Diamba Sud.
• Resource Growth Drivers:
  • Infill drilling at Area A, Area D, Karakara, Southern Arc, Moungoundi, and Western Splay converted inferred resources to indicated resources, increasing confidence.
  • Expansion drilling at Southern Arc and Moungoundi resulted in increased mineral resources for these specific deposits.
  • Updated gold price assumption of $3,300 USD per ounce applied in the estimation process.
• Exploration Status: Continued exploration drilling at Southern Arc, Moungoundi, and new targets has intersected mineralization beyond current resource envelopes, indicating further growth potential. Drilling is planned to continue throughout 2026.
• Feasibility Study: Progressing toward completion by the end of Q2 2026 to support a potential construction decision targeted for mid-2026.
• Qualified Person: Eric Chapman, Senior Vice-President, Technical Services, reviewed and approved the scientific and technical information.

Notable Quotes

• "This updated mineral resource estimate represents a significant advancement for the Diamba Sud gold project, highlighted by a 73-per-cent increase in indicated gold ounces with 94 per cent of total gold ounces now in the indicated category. This update provides a strong foundation for the feasibility study we plan to publish by midyear 2026 and materially advances the project toward a final investment decision." — Jorge A. Ganoza, President and CEO
• "Diamba Sud, together with the expansion of the Seguela mine, currently under study, is central to our strategy to grow Fortuna into a company capable of producing more than 500,000 ounces of gold annually from long-life assets." — Jorge A. Ganoza, President and CEO