FVI.TO · 2026-02-25 12:00:00

Fortuna intersects 6.0 g/t gold over 24.1 meters at Southern Arc, Diamba Sud Project, Senegal

Drill Results

NEWS RELEASE

Fortuna intersects 6.0 g/t gold over 24.1 meters at Southern Arc,

Diamba Sud Project, Senegal

Vancouver, British Columbia, February 25, 2026: Fortuna Mining Corp. (NYSE: FSM | TSX: FVI)

is pleased to report the latest batch of exploration drilling results from the Southern Arc deposit at its

Diamba Sud Gold Project located in Senegal. A further 44 reverse circulation and diamond drill holes,

totalling 7,518 meters, have been completed at Southern Arc since the previous exploration results

update in December 2025 and were incorporated into the expanded Diamba Sud mineral resource

(refer to Fortuna news release dated February 19, 2026, “Fortuna expands Indicated Mineral Resource

by 73% to 1.25 million gold ounces, Diamba Sud Project, Senegal”).

Paul Weedon, Senior Vice President of Exploratio n, commented “Infill and extension drilling at

Southern Arc continues to strengthen the scale and confidence of the deposit , contributing to the

updated and expanded updated Mineral Resource of 6 million tonnes averaging 1.9 g/t Au, containing

367,000 gold ounces, making it today the largest single mineral deposit at the growing Diamba Sud

Project.” Mr. Weedon concluded, “Southern Arc remains open at depth and along strike to both the

southwest and northeast, with drilling continuing. Importantly, most drilling across the total project area

is considered relatively shallow at less than 200 meters depth , underscoring the potential for further

resource growth at Diamba Sud.”

Southern Arc Drilling highlights

DSDD606: 8.4 g/t Au

22.4 g/t Au

over an estimated true width of 10.4 meters from 136 meters including

over an estimated true width of 1.6 meters from 145 meters

DSDD608: 6.0 g/t Au

20.0 g/t Au

29.8 g/t Au

13.9 g/t Au

3.0 g/t Au

18.6 g/t Au

over an estimated true width of 24.1 meters from 80 meters, including

over an estimated true width of 0.8 meters from 80 meters, and

over an estimated true width of 2.4 meters from 84 meters, and

over an estimated true width of 0.8 meters from 109 meters,

over an estimated true width of 13.6 meters from 167 meters, including

over an estimated true width of 0.8 meters from 176 meters

DSDD612: 6.4 g/t Au

12.6 g/t Au

2.4 g/t Au

10.7 g/t Au

10.3 g/t Au

25.5 g/t Au

19.0 g/t Au

over an estimated true width of 4.6 meters from 102 meters, including

over an estimated true width of 1.4 meters from 106 meters

over an estimated true width of 6.2 meters from 115.3 meters, including

over an estimated true width of 0.8 meters from 118 meters

over an estimated true width of 7.2 meters from 135.45 meters, including

over an estimated true width of 1.2 meters from 135.45 meters, and

over an estimated true width of 0.8 meters from 139 meters

DSDD614: 10.1 g/t Au

13.7 g/t Au

16.5 g/t Au

over an estimated true width of 12.1 meters from 141.75 meters, including

over an estimated true width of 0.8 meters from 146 meters, and

over an estimated true width of 4.0 meters from 148 meters

DSDD642: 2.3 g/t Au

10.9 g/t Au

11.5 g/t Au

over an estimated true width of 36 meters from 229 meters, including

over an estimated true width of 0.8 meters from 246 meters, and

over an estimated true width of 0.8 meters from 248 meters

DSR1039: 5.2 g/t Au over an estimated true width of 24 meters from 90 meters, including

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43.8 g/t Au

12.4 g/t Au

36.1 g/t Au

over an estimated true width of 0.8 meters from 95 meters, and

over an estimated true width of 0.8 meters from 100 meters, and

over an estimated true width of 0.8 meters from 112 meters

At Southern Arc, key objectives include continuing step-out drilling to test strike and depth extensions

along strike to the southwest, northeast, and south, where mineralization remains open (see Figures

2 and 3). For example, drill hole DSDD606 (Figure 2) returned 8.4 g/t gold over an estimated true width

of 10.4 meters from 136 meters and downhole, and a further 2.6 g/t gold over an estimated true width

of 10.6 meters from 181 meters, highlighting the open nature of the system. Additional step-out drilling

to test depth and strike projections is planned for the second quarter of 2026 along with re-entry and

deepening of historic hole DSR936, which previously terminated short of the mineralized zone.

Mineralization at Southern Arc occurs as variable fine stockwork vein arrays and diffuse pyrite-silica

flooding, with a strong spatial association to hydrothermal breccias and carbonate units (Figures 2

and 3). The system commonly exhibits extensive hematite alteration , consistent with mineralization

observed at other prospects at Diamba Sud.

Drilling is continuing with 5 drill rigs across the project site testing multiple targets.

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Figure 1: Diamba Sud Gold Project: Location of Mineral Resource Deposits

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Figure 2: Diamba Sud Gold Project: Southern Arc deposit - section 700NE. (For details of past release,

refer to Fortuna news release dated August 13, 2025, “Fortuna drills 22.7 g/t gold over 21.6

meters at Southern Arc, Diamba Sud Gold Project, Senegal”)

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Figure 3: Diamba Sud Gold Project: Southern Arc deposit - Section 675NE. (For details of past

release, refer to Fortuna news release dated August 13, 2025, “ Fortuna drills 22.7 g/t gold

over 21.6 meters at Southern Arc, Diamba Sud Gold Project, Senegal”)

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Moungoundi Drilling Highlights

DSDD639: 15.8 g/t Au

44.1 g/t Au

over an estimated true width of 4.8 meters from 16 meters, including

over an estimated true width of 1.6 meters from 17 meters

DSDD654: 7.8 g/t Au

6.2 g/t Au

16.8 g/t Au

40.9 g/t Au

over an estimated true width of 1.6 meters from 35 meters

over an estimated true width of 9.6 meters from 53 meters, including

over an estimated true width of 0.8 meters from 53 meters, and

over an estimated true width of 0.8 meters from 55 meters

DSDD662: 7.2 g/t Au

27.6 g/t Au

over an estimated true width of 9.6 meters from 42 meters, including

over an estimated true width of 1.6 meters from 51 meters

DSR1022: 2.2 g/t Au

15.7 g/t Au

over an estimated true width of 19.2 meters from 35 meters, including

over an estimated true width of 0.8 meters from 57 meters

A further 4 6 reverse circulation and diamond core drill holes , totalling 4,471 meters, have been

completed at Moungoundi since the previous exploration update and have been incorporated into the

recently updated Diamba Sud Mineral Resource estimate. The program was designed to upgrade

resource confidence through infill drilling while also expanding the mineralized footprint through step-

out drilling. Mineralization remains open at depth and along strike, and additional drilling is planned to

test for potential extensions and possible structural links to the adjacent Western Splay deposit.

Mineralization at Moungoundi occurs within intercalated hydrothermal breccias, carbonate

metasedimentary units, and granitic to dioritic intrusive rocks. Mineralization is typically associated

with vein arrays preferentially hosted within hydrothermal breccias.

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Area D, Karakara, and Kassasoko Infill Drilling Highlights

Area D

DSDD652:

2.7 g/t Au

13.2 g/t Au

2.8 g/t Au

12.6 g/t Au

13.8 g/t Au

over an estimated true width of 28 meters from 21 meters, including

over an estimated true width of 0.8 meters from 30 meters

over an estimated true width of 37.6 meters from 60 meters, including

over an estimated true width of 0.8 meters from 75 meters, and

over an estimated true width of 2.4 meters from 91 meters

DSDD655: 46.3 g/t Au

724.0 g/t Au

21.5 g/t Au

14.3 g/t Au

over an estimated true width of 13.6 meters from 43 meters, including

over an estimated true width of 0.8 meters from 44 meters, and

over an estimated true width of 0.8 meters from 52 meters, and

over an estimated true width of 0.8 meters from 54 meters

Karakara

DSDD643:

36.3 g/t Au

105.0 g/t Au

over an estimated true width of 2.4 meters from 48 meters, including

over an estimated true width of 0.8 meters from 50 meters

Kassasoko

DSR1054:

1.3 g/t Au

over an estimated true width of 22.4 meters from 26 meters

DSR1059: 1.4 g/t Au over an estimated true width of 12.0 meters from 25 meters

An additional 17 infill drill holes, totaling 1,773 meters, were completed at Area D , Kassasoko, and

Karakara (Figure 1). The program was designed to enhance resource confidence by targeting areas

previously classified as Inferred Mineral Resources within the recently released updated Diamba Sud

Mineral Resource.

Refer to Appendix 1 for full details of the drill holes and assay results for this drill program.

Quality Assurance & Quality Control (QA - QC)

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 (RC) 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 a ir 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 percent representative sample for submission to the analytical laboratory.

The residual 87.5 percent 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.

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All RC and DD samples were transported by Company vehicle or commercial courier to ALS Global’s

preparation laboratories in Kedougou, Senegal with prepared sample pulps then transported via

commercial courier to ALS Global’s analytical 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. Samples returning assays >10 ppm Au were reanalyzed using a 50 -gram charge and fire

assay with a gravimetric finish. Quality control procedures included the systematic insertion of blanks,

duplicates and sample standards into the sample stream. In addition, the ALS Global laboratory

inserted its own quality control samples.

Qualified Person

Paul Weedon, Senior Vice President, 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 three operating mines and

a portfolio of exploration projects in Argentina, Côte d’Ivoire, Mexico, and Peru, as well as the Diamba

Sud Gold Project in Senegal. Sustainability is at the core of our operations and stakeholder

relationships. We produce gold and silver while creating long -term shared value through efficient

production, environmental stewardship, and social responsibility. For more information, please visit

our website at www.fortunamining.com

ON BEHALF OF THE BOARD

Jorge A. Ganoza

President, CEO, and Director

Fortuna Mining Corp.

Investor Relations:

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