Fortuna's Sunbird Mineralization Expands Significantly: High-Grade Gold Zone Extends Beyond Previous Resource Estimates at Séguéla

Vancouver, BC — Fortuna Mining Corp. (NYSE: FSM | TSX: FVI) has released encouraging exploration results from its ongoing drilling campaign at the Sunbird deposit, located within the Séguéla Mine in Côte d’Ivoire. The latest assay data, reported on February 12, 2026, demonstrates that premium-grade gold mineralization continues to develop at greater depths, expanding both vertically and laterally from previously defined resource boundaries.

The drilling program has successfully delineated high-grade intercepts across multiple zones, with a standout result of 6.1 g/t Au over an estimated true width of 18.9 meters recovered from drill hole SGDD148. This extended intercept, coupled with numerous other significant results, underscores the deposit’s considerable potential for resource expansion.

Deep Drill Program Delivers Multiple High-Grade Intercepts

The exploration team has completed 22 additional drill holes totaling 9,816 meters at Sunbird, representing a systematic infill and extension drilling initiative. These results follow the June 30, 2025 resource evaluation cutoff date, meaning all reported intercepts represent new mineralization discovery beyond the current Mineral Resource and Mineral Reserves envelopes.

The drilling campaign reveals a consistent pattern of high-grade mineralization at depth. Notable intercepts include 15.4 g/t Au over 4.2 meters in SGRD2473, which contains a higher-grade core of 26.2 g/t Au over 2.1 meters. Similarly, drill hole SGRD2491 returned 5.2 g/t Au across 8.4 meters, with internal assays reaching 29.6 g/t Au over narrower intervals. These results reflect the typical structure of the deposit, where broad mineralized zones contain discrete high-grade shoots.

One of the most encouraging findings came from SGDD148, which intersected 73.5 g/t Au over 0.7 meters at 530 meters depth, indicating the presence of ultra-high-grade mineralization at significant depths. The same hole continued to return strong values deeper in the sequence, including the previously mentioned 6.1 g/t Au zone.

Drill hole SGDD149 extended mineralization into a new structural domain, intersecting 13.0 g/t Au over 4.2 meters at 686 meters depth—approximately 400 meters beyond the existing resource envelope. This breakthrough suggests the mineralized system extends much deeper than previously modeled, with potential for significant resource growth.

Mineralization Remains Open at Depth and Along Strike

The drilling program has specifically targeted two mineralization domains within Sunbird: the upper and lower shoots. Infill drilling between these zones has successfully demonstrated connectivity, with results such as 4.1 g/t Au over 11.9 meters from 499 meters depth in SGRD2487. This discovery is significant as it suggests a potentially larger, more continuous mineralized body than the current resource model indicates.

The lower shoot, the primary focus of the recent drilling, shows particular promise. Multiple drill holes have extended this zone progressively downward and laterally. The deepest intercepts, approaching 700 meters below surface, continue to return meaningful gold grades, suggesting the mineralization has not reached its depth limits within the tested area.

According to Paul Weedon, Senior Vice President of Exploration, “Continued drilling at Sunbird confirms that high-grade mineralization remains wide open at depth.” He further noted, “With five drill rigs currently focused on Sunbird, these results build on previously announced high-grade drill intercepts and further underpin the potential for resource growth.”

The mineralization also appears to remain open along strike, with drilling having tested only a portion of the deposit’s prospective dimensions. The company plans to continue drilling throughout 2026, with five active drill rigs maintaining systematic coverage across multiple target areas.

Technical Methodology and Quality Assurance

All drilling has been conducted under the direct supervision of Fortuna’s experienced personnel, with rigorous quality control protocols maintained throughout the program. Reverse circulation (RC) drilling utilized 5.25-inch pneumatic hammers with samples collected into 60-liter plastic bags. Samples were maintained dry through controlled air pressure to exclude groundwater. When water ingress threatened core integrity, drilling was converted to diamond core tails to ensure sample quality.

All RC samples were processed using a three-tier riffle splitter to generate 12.5 percent representative samples for laboratory analysis, with the remaining 87.5 percent retained at the drill site as backup material until assay validation was complete. Coarse reject samples from all significant mineralized intervals have been systematically retained and stored at the company-controlled core yard.

Diamond drilling holes were initiated with HQ-diameter core, progressively reduced to NQ diameter upon intersecting fresh rock. Core logging and sampling followed industry-standard protocols, with one-meter sample intervals or sampling to geological boundaries. Cores were split with diamond saws, with one half retained in original core boxes for archival storage and the other half processed for analysis.

Sample transport was managed through company vehicles and commercial couriers to either ALS Global’s preparation facility in Yamoussoukro or Bureau Veritas’ laboratory in Abidjan, both located in Côte d’Ivoire. ALS Global samples were further transported to their analytical laboratory in Ouagadougou, Burkina Faso. Routine gold assaying employed a 50-gram fire assay charge with atomic absorption finish for all samples. Results exceeding 10 ppm Au were systematically re-analyzed using a 50-gram fire assay with gravimetric finish to ensure accuracy.

Quality control procedures included systematic insertion of blanks, duplicates, and sample standards throughout the analytical stream. Both ALS Global and Bureau Veritas maintained independent quality control protocols, ensuring multiple verification layers for data integrity.

Professional Verification and Qualified Person Certification

Paul Weedon, Senior Vice President of Exploration at Fortuna Mining Corp., is a Qualified Person under Canadian National Instrument 43-101, holding membership #6001 with the Australian Institute of Geoscientists. Mr. Weedon has personally reviewed and approved all scientific and technical information contained in this announcement. His verification process included comprehensive review of geochemical and geological databases, examination of diamond drill core, and confirmation of sampling and analytical methodologies. No limitations were identified in the verification process.

Strategic Implications for Resource Development

The Sunbird deposit now demonstrates characteristics consistent with a significant mineralized system capable of supporting long-term mining operations. The combination of broad, lower-grade zones containing discrete high-grade shoots provides operational flexibility for mining engineering and ore processing optimization. The fact that mineralization remains open at depth and along strike suggests the resource base could expand materially through continued systematic exploration.

Fortuna Mining Corp. operates three producing mines and maintains an active exploration portfolio across Argentina, Côte d’Ivoire, Mexico, Peru, and Senegal. The company prioritizes sustainable mining practices and value creation for stakeholders through efficient production, environmental stewardship, and social responsibility initiatives. Additional information regarding the company’s operations and strategy is available at www.fortunamining.com.

For inquiries regarding this announcement, investors may contact Fortuna Mining Corp. through their investor relations department, led by Carlos Baca.