Fortuna delivers robust PEA for Diamba Sud Gold Project in Senegal: After-tax IRR of 72% and NPV5% of US$563 million using US$2,750 per ounce

On October 15, 2025, Fortuna Mining Corp. announced a robust Preliminary Economic Assessment (PEA) for its Diamba Sud Gold Project in Senegal. The study, using a long-term gold price of US$2,750 per ounce, highlights strong project economics: * After-tax Net Present Value (NPV) at a 5% discount rate: US$563 million * After-tax Internal Rate of Return (IRR): 72% * Payback Period: 0.8 years (10 months) * Initial Capital Expenditure (Capex): US$283.2 million * Life of Mine (LOM): 8.1 years * Average Annual Production (LOM): 106,000 ounces of gold * Average All-In Sustaining Cost (AISC LOM): US$1,238 per ounce

The company is proceeding with a Definitive Feasibility Study (DFS), targeted for completion by the end of Q2 2026, and anticipates a construction decision in the first half of 2026. Fortuna has also approved a US$17 million budget for early works, including camp expansion and detailed engineering. Exploration continues with five drill rigs to expand mineralization and upgrade Inferred resources.

This PEA is a significant and positive de-risking milestone for Fortuna's key growth asset, Diamba Sud. The release of economic metrics confirms the project's potential to be a major contributor to the company's future production profile. The timing of the PEA is consistent with previous guidance from August and October 2025, which projected completion in Q4 2025.

Key Positives: * Strong Economics: An after-tax NPV of US$563 million represents a material addition to Fortuna's value, which has a market cap of approximately US$3.95 billion. The 72% IRR and sub-one-year payback period are exceptionally strong, suggesting a highly profitable operation under the study's assumptions. * De-risking and Path to Production: The PEA provides a clear development timeline, with a DFS expected in Q2 2026, a construction decision in H1 2026, and first gold pour targeted for Q2 2028. The approval of a $17 million budget for early works demonstrates the company's confidence and commitment to advancing the project. * Fundable Capex: The initial capex of US$283.2 million appears manageable. As of Q2 2025, Fortuna had a net cash position of US$214.8 million and liquidity of US$537.3 million. Combined with ongoing free cash flow from its producing assets, the company is in a strong position to fund construction internally, minimizing the need for dilutive equity financing or significant new debt. * Exploration Upside: The PEA is based on the July 2025 resource estimate. Subsequent drill results announced on August 13, 2025 (e.g., 22.7 g/t Au over 21.6 meters) were not included and highlight the significant potential to expand the resource and extend the mine life beyond the current 8.1 years.

Critical Assessment and Risks: * Aggressive Gold Price Assumption: The most significant risk is the use of a US$2,750/oz long-term gold price. While the company realized even higher prices in mid-2025 (Q2 average of $3,315/oz at Séguéla), this is an extremely optimistic assumption for a LOM study. The project's economics would be substantially weaker at more conservative, historical average gold prices. The lack of a sensitivity analysis in the news release obscures how vulnerable the project's returns are to gold price fluctuations. This is a classic example of a company presenting information in the best possible light. * Preliminary Nature: A PEA is a preliminary study with a lower level of accuracy than a Pre-Feasibility or Feasibility Study. The initial capex of $283.2M includes a $46.4M contingency, but cost estimates could increase in the DFS. * Sovereign Risk: The project is in Senegal. The PEA notes the government holds a 10% free-carried interest and has the right to acquire up to an additional 25% interest under the mining code. The terms for this additional acquisition are not specified and represent a future risk to the project's economics for Fortuna shareholders.

Overall, the news is materially positive as it provides a tangible economic framework for the company's primary growth project and confirms a clear path to production. However, the reliance on a high gold price for the headline numbers warrants significant caution. It meets, but does not wildly exceed, expectations for a project of this nature.

Fortuna Mining Corp. is a mid-tier precious metals producer with three operating gold mines in West Africa (Séguéla in Côte d’Ivoire, Lindero in Argentina) and one polymetallic mine in Peru (Caylloma). The company has streamlined its portfolio, divesting its Yaramoko and San Jose mines in 2025 to focus on longer-life, lower-cost assets.

The company's flagship development project is the Diamba Sud Gold Project in Senegal, acquired via the takeover of Chesser Resources in September 2023. Fortuna has been aggressively drilling the project, significantly increasing the mineral resource in 2025. The just-released PEA outlines a conventional open-pit, carbon-in-leach (CIL) operation with a planned output of over 100,000 ounces per year, representing the company's next major phase of growth.