News Summary
On December 8, 2025, Fortuna Mining announced additional strong exploration results from its Diamba Sud Gold Project in Senegal. The headline highlighted intercepts from hole DSDD574, which returned 1.7 g/t gold over an estimated true width of 29.6 meters and a further 2.0 g/t gold over 20.0 meters.
Other significant intercepts reported in the release from the Southern Arc deposit include:
– DSDD555: 6.8 g/t Au over a true width of 35.5 meters
– DSDD558: 8.8 g/t Au over a true width of 14.4 meters
– DSDD563: 5.8 g/t Au over a true width of 20.8 meters, and 12.2 g/t Au over a true width of 5.8 meters
– DSDD567: 4.6 g/t Au over a true width of 26.6 meters
The drilling program, comprising both infill and extensional holes, successfully expanded mineralization to the southwest of the current optimized pit shell defined in the October 2025 Preliminary Economic Assessment (PEA). The results from this ongoing 63-hole, 9,619-meter program will be included in an updated Mineral Resource Estimate (MRE) scheduled for Q1 2026, which will form the basis of a Definitive Feasibility Study (DFS).
Material Impact
The drill results announced on December 8 are materially positive. While presented as a routine exploration update, they provide critical confirmation and expansion of mineralization at the company’s most important growth project, Diamba Sud. The results, particularly the high-grade, wide intercepts not featured in the headline, reinforce the quality of the deposit and increase confidence that the upcoming MRE and subsequent DFS will improve upon the already robust economics outlined in the October 2025 PEA (after-tax IRR of 72% and NPV5% of US$563 million).
This news is the latest in a consistent stream of positive developments over the past year that demonstrate flawless execution of a well-defined strategy:
1. Portfolio Optimization: Fortuna successfully divested its non-core, higher-cost, and shorter-life assets, the San Jose mine in Mexico (April 2025) and the Yaramoko mine in Burkina Faso (May 2025). This streamlined the portfolio and de-risked the company by exiting a challenging jurisdiction.
2. Balance Sheet Fortification: These divestitures, combined with record free cash flow from operations, have created a fortress balance sheet. As of Q3 2025, Fortuna reported a net cash position of $266 million and liquidity of $588 million. This is more than sufficient to internally fund the entire initial capex for Diamba Sud, estimated at $283 million in the PEA, eliminating financing risk.
3. Growth at Séguéla: The flagship Séguéla mine has been a star performer, consistently exceeding production expectations. Aggressive and successful exploration throughout 2025, particularly at the Sunbird and Kingfisher deposits, led to a significant MRE update on November 18, extending the mine life to 7.5 years. This immediately prompted the initiation of a plant expansion study (announced December 3) to increase annual production toward 200,000 ounces.
4. De-risking Diamba Sud: The company has systematically advanced Diamba Sud, meeting every timeline. The project delivered a major resource update in August, a stellar PEA in October, and achieved a key permitting milestone with the ESIA filing in October. The continued positive drill results, including today’s, provide strong evidence that the project’s scale will likely grow.
The December 8 news confirms that the exploration momentum at Diamba Sud is strong, setting up the Q1 2026 MRE as the next major positive catalyst. The company is successfully advancing a powerful, fully-funded, two-pronged organic growth strategy that promises to significantly increase production and shareholder value in the coming years.
Catalysts
– Q4 2025 Financial Results: Expected in early March 2026. Look for continued strong free cash flow generation and further growth in the net cash position.
– Updated Mineral Resource Estimate for Diamba Sud: Expected in Q1 2026. This is a key catalyst that will incorporate all recent drilling, including these positive results, and will form the basis for the Definitive Feasibility Study.
– Definitive Feasibility Study (DFS) for Diamba Sud: Expected towards the end of Q2 2026. This will provide updated and more detailed project economics and capital costs.
– Diamba Sud Construction Decision: The company has guided for a construction decision in the first half of 2026, likely following the release of the DFS.
– Séguéla Mine Plant Expansion Study Results: Expected in Q2 2026. This will outline the scope, cost, and timeline for increasing throughput and pushing annual production above 200,000 ounces.
Materiality Conclusion
The news is materially positive. It is not a standalone “game-changer” but serves as a crucial building block in the company’s well-executed growth strategy. By successfully expanding the mineralized footprint at Diamba Sud, the results de-risk the project’s development, increase the probability of an enhanced Definitive Feasibility Study, and reinforce the clear, fully-funded growth trajectory that Fortuna has established.
