Fortuna Mining Corp. (NYSE: FSM | TSX: FVI) is pleased to provide an update on its exploration programs at the Diamba Sud Gold Project in Senegal.

Paul Weedon, Senior Vice President of Exploration at Fortuna, commented, “Drilling at Karakara continues to improve our understanding of the prospect’s potential, returning several high-grade intercepts including a highlight intersection of 31.3 g/t Au over an estimated true width of 12.0 meters in drill hole DSDD243. The exploration team is looking forward to utilizing the improved understanding of the geological controls on gold mineralization to further advance the regional exploration programs.” Mr. Weedon concluded, “Our focus has now moved towards progressing some of the many satellite opportunities at Diamba Sud, with highly encouraging, early-stage results such as 8.9 g/t Au over an estimated true width of 27.7 meters returned from drill hole DSR680 at Western Splay, and 2.9 g/t Au over an estimated true width of 15.3 meters returned from drill hole DSDD262 at Kassasoko. These prospects represent new opportunities for additional ounces and continue to highlight the prospectivity of the wider Diamba Sud Gold Project.”

Diamba Sud Gold Project, Senegal

Drilling at Diamba Sud has continued with the focus moving to testing and upgrading several key high priority satellite prospects (refer to Figure 1), including Western Splay and Kassasoko, as well as further work to improve the definition and understanding of the mineralization controls at Bougouda and Karakara. An additional 20,665-meter, 159-hole program has been completed at Diamba Sud since March 2024 (refer to Fortuna news release dated March 11, 2024).

Results from this program will be incorporated into the ongoing project development work, with the encouraging results from Western Splay and Kassasoko expected to contribute toward growing the project portfolio and resource base, while also improving confidence in the regional geological understanding. With the tempo of drilling planned to slow across the forthcoming rainy season, the exploration team will continue to review and fine-tune the geological controls on mineralization.

Figure 1: Diamba Sud Gold Project location plan

Karakara Prospect

Infill and extension drilling at Karakara continued to define additional mineralization beyond the historic pit design, while also providing confirmatory data to help validate previous geological interpretations.

Karakara drilling highlights include:

An updated interpretation supported by further drilling will take place during the third quarter of 2024 to further refine the controls on mineralization, the association with the nearby Area D and the Moungoundi to Southern Arc prospects (refer to Figure 2).

Figure 2: Karakara cross-section showing select results – looking north

Kassasoko Prospect

Drilling at Kassasoko, located approximately 1-kilometer to the southeast of Western Splay, was successful in intersecting several broad zones of mineralization. Drilling highlights include:

In comparison to mineralization elsewhere at Diamba Sud, mineralization at Kassasoko is hosted within a granitic unit and in close proximity to a series of dioritic intrusives (refer to Figure 3). Exploration work is continuing.

Figure 3: Kassasoko cross-section showing select results – looking northeast

Western Splay drilling highlights include:

Drilling continues, extending further to the south to test below an active artisanal area, with the objective of increasing the prospect footprint, as well as improving the geological interpretation of the wider southern area of Diamba Sud, particularly the relationships between the Moungoundi-Western Splay-Kassasoko-Southern Arc prospects.

Figure 4: Western Splay cross-section showing select results – looking north

Refer to Appendix 1 for full details of the drill holes and assay results for this drill program at the Diamba Sud Gold Project.

Quality Assurance & Quality Control

All drilling data completed by the Company utilized the following procedures and methodologies. All drilling was carried out under the supervision of the Company’s personnel.

All reverse circulation drilling used a 5.25-inch face sampling pneumatic hammer with samples collected into 60-liter plastic bags. Samples were kept dry by maintaining enough air pressure to exclude groundwater inflow. If water ingress exceeded the air pressure, RC drilling was stopped, and drilling converted to diamond core tails. Once collected, RC samples were riffle split through a three-tier splitter to yield a 12.5% representative sample for submission to the analytical laboratory. The residual 87.5% samples were stored at the drill site until assay results were received and validated. Coarse reject samples for all mineralized samples corresponding to significant intervals are retained and stored on-site at the Company-controlled core yard.

All diamond drilling (DD) drill holes started with HQ sized diameter, before reducing to NQ diameter diamond drill bits on intersecting fresh rock. The core was logged, marked up for sampling using standard lengths of one meter or to a geological boundary. Samples were then cut into equal halves using a diamond saw. One half of the core was left in the original core box and stored in a secure location at the Company core yard at the project site. The other half was sampled, catalogued, and placed into sealed bags and securely stored at the site until shipment.

All RC and DD samples were transported to ALS’s preparation laboratory in Kedougou, Senegal before also being transported via commercial courier, to ALS’s facility in Ouagadougou, Burkina Faso. Routine gold analysis using a 50-gram charge and fire assay with an atomic absorption finish was completed for all samples. Quality control procedures included the systematic insertion of blanks, duplicates and sample standards into the sample stream. In addition, the ALS laboratory inserted its own quality control samples.

Qualified Person

Paul Weedon, Senior Vice President of Exploration for Fortuna Mining Corp., is a Qualified Person as defined by National Instrument 43-101 being a member of the Australian Institute of Geoscientists (Membership #6001). Mr. Weedon has reviewed and approved the scientific and technical information contained in this news release. Mr. Weedon has verified the data disclosed, including the sampling, analytical and test data underlying the information or opinions contained herein by reviewing geochemical and geological databases and reviewing diamond drill core. There were no limitations to the verification process.

About Fortuna Mining Corp.

Fortuna Mining Corp. is a Canadian precious metals mining company with five operating mines in Argentina, Burkina Faso, Côte d’Ivoire, Mexico, and Peru. Sustainability is integral to all our operations and relationships. We produce gold and silver and generate shared value over the long-term for our stakeholders through efficient production, environmental protection, and social responsibility.

Appendix 1: Diamba Sud Gold Project, Senegal

Explanatory Notes:

1. EOH – End of hole
2. NSI: No significant intercepts
3. ETW: Estimated true width
4. Depths and widths reported to nearest significant decimal place
5. DD: diamond drilling tail | RC: reverse circulation drilling