
Core Viewpoint - Fortuna Mining Corp. has released an updated Mineral Resource estimate for the Diamba Sud Gold Project in Senegal, indicating significant increases in both Indicated and Inferred Mineral Resources as of July 7, 2025 [1][8]. Summary by Category Mineral Resource Estimates - The Diamba Sud Gold Project contains an Indicated Mineral Resource of 14.2 million tonnes (Mt) at an average gold grade of 1.59 grams per tonne (g/t), equating to 724,000 ounces of gold [3][6]. - The Inferred Mineral Resource is estimated at 6.2 Mt with an average gold grade of 1.44 g/t, containing 285,000 ounces of gold [3][10]. - The Indicated Mineral Resource has increased by 53% since year-end 2024, while the Inferred Mineral Resource has seen a 93% increase over the same period [8]. Drilling and Resource Expansion - The updated estimate is based on new drilling conducted from July 2024 to July 2025, involving 243 holes and totaling 31,652 meters [4]. - New resource estimates for the Southern Arc and Moungoundi deposits have been introduced, with initial Inferred Mineral Resource estimates of 194,000 ounces and 31,000 ounces of gold, respectively [8][10]. Economic Analysis and Future Plans - A Preliminary Economic Analysis (PEA) is currently underway, with completion expected in the fourth quarter of 2025 [8]. - Exploration drilling at Southern Arc is ongoing, focusing on infilling and expansion drilling to upgrade Inferred Resources and explore open mineralization [9]. Geological Interpretation and Methodology - Infill drilling has improved geological interpretation and supported the conversion of Inferred Resources to Indicated Resources [9]. - The resource estimate incorporates data from 1,178 diamond and reverse circulation drill holes, totaling 154,814 meters, completed since 2019 [11]. Price Assumptions and Cost Refinements - The long-term gold price assumption has been increased to $2,600 per ounce, which, along with refinements to mining and processing costs, has contributed to updated pit shell optimization [9][26].