Mr. Jorge Ganoza reports

FORTUNA EXPANDS INDICATED MINERAL RESOURCE BY 73% TO 1.25 MILLION GOLD OUNCES, DIAMBA SUD PROJECT, SENEGAL

Fortuna Mining Corp. has released an updated mineral resource estimate for the Diamba Sud gold project, effective Jan. 16, 2026. Indicated mineral resources total 1.25 million ounces of gold, reflecting an increase of 530,000 ounces from the prior estimate and demonstrating open resource growth potential.

Jorge A. Ganoza, president and chief executive officer, commented: "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." Mr. Ganoza continued, "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."

Updated mineral resource highlights:

• Total indicated mineral resources of 26.0 million tonnes averaging 1.50 g/t Au, containing 1.25 million ounces of gold;
• First-time estimation of indicated mineral resources at the Southern Arc deposit, comprising 6.0 million tonnes averaging 1.91 g/t Au and containing 367,000 ounces of gold, establishing Southern Arc as the largest gold deposit discovered to date at Diamba Sud;
• Infill drilling successfully upgraded inferred to indicated mineral resource category at the Area D, Southern Arc, Moungoundi and Karakara deposits, increasing resource confidence;
• Technical studies are advancing for the estimation of mineral reserves, with a feasibility study targeted for completion by the end of Q2 2026;
• Continuing exploration drilling of Southern Arc, Moungoundi and additional new targets continues to intersect mineralization beyond the current mineral resource envelopes, highlighting further growth potential.

Mineral resources

Fortuna estimates that the Diamba Sud gold project contains indicated mineral resources of 26.0 million tonnes at an average gold grade of 1.50 g/t, containing 1,254,000 ounces of gold, and inferred mineral resources of 2.1 million tonnes at an average gold grade of 1.13 g/t, containing 77,000 ounces of gold.

The updated mineral resource estimate incorporates drilling completed between July, 2025, to January, 2026. The additional data enhanced geological interpretation and resource modelling at Area A, Area D, Karakara and Western Splay and supported resource growth at Southern Arc and Moungoundi. Expansion drilling at Southern Arc and Moungoundi, together with drilling of new regional targets, is continuing and is planned to continue throughout 2026, with the objective of further delineating mineralization beyond the current mineral resource envelopes.

Changes from the previous mineral resource estimate are primarily attributable to:

• Infill drilling at Area A, Area D, Karakara, Southern Arc, Moungoundi and Western Splay, which improved geological interpretation and supported the conversion of inferred resources to indicated resources, increasing overall resource confidence;
• Expansion drilling at Southern Arc and Moungoundi resulted in increased mineral resources for these deposits;
• An updated gold price assumption of $3,300 (U.S.) per ounce, applied in the resource estimation process.

Feasibility study

Fortuna is progressing with the feasibility study for the Diamba Sud Gold Project to support a potential construction decision targeted for mid-2026, with delivery of the study expected by the end of Q2 2026.

Qualified person

Eric Chapman, senior vice-president, technical services, is a professional geoscientist of the Association of Professional Engineers and Geoscientists of the Province of British Columbia (registration No. 36328) and a qualified person as defined by National Instrument 43-101, Standards of Disclosure for Mineral Projects. Mr. Chapman has reviewed and approved the scientific and technical information contained in this news release and has verified the underlying data.

About Fortuna Mining Corp.

Fortuna Mining is a Canadian precious metals mining company with three operating mines and a portfolio of exploration projects in Argentina, Ivory Coast, Mexico and Peru as well as the Diamba Sud gold project in Senegal. Sustainability is at the core of the company's operations and stakeholder relationships. Fortuna Mining produces gold and silver while creating long-term shared value through efficient production, environmental stewardship and social responsibility.

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