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Fortuna drills 4.5 g/t Au over 37.4 meters at Kingfisher and 11.2 g/t Au over 5.6 meters at Sunbird, Séguéla Mine, Côte d’Ivoire

Drill Results

NEWS RELEASE

Fortuna drills 4.5 g/t Au over 37.4 meters at Kingfisher and 11.2 g/t Au

over 5.6 meters at Sunbird, Séguéla Mine, Côte d’Ivoire

Vancouver, August 18, 2025: Fortuna Mining Corp. (NYSE: FSM | TSX: FVI) is pleased to report

updated exploration drilling results from the Kingfisher and Sunbird deposits at the Séguéla Mine in

Côte d’Ivoire.

Paul Weedon, Senior Vice President of Exploration at Fortuna, commented, “A successful infill drill

program was completed at Kingfisher , with several notable intersections confirming the broad nature

of the mineralization, including 4.5 g/t Au over an estimated true width of 37.4 meters from 79 meters

in drill hole SGRD2363. Exploration has now turned to further extending the strike and de pth at

Kingfisher, successfully intersecting mineralization 300 meters below surface and a further 250 meters

along strike.”

Mr. Weedon continued “Deep exploration drilling testing the southern extent of Sunbird has continued

to return excellent results while upgrading the geological confidence and expanding the mineralized

envelope, with results including 8.5 g/t Au over an estimated true width of 7.0 meters from 566 meters

in drill hole SGRD2431. In addition, drilling has recently identified near surface shallow mineralization

approximately 180 meters into the footwall, with results including 2.1 g/t over an estimated true width

of 8.4 meters from 32 meters in drill hole SGRD2418 and 5.6 g/t Au over an estimated true width of

4.9 meters from 98 meters in drill hole SGRD2422. Mineralization remains open at depth and along

strike.”

Kingfisher Deposit Drilling Highlights

SGRD2313: 9.4 g/t Au

58.1 g/t Au

36.2 g/t Au

2.1 g/t Au

12.1 g/t Au

over an estimated true width of 17.0 meters from 105 meters, including

over an estimated true width of 0.9 meters from 118 meters, and

over an estimated true width of 2.6 meters from 121 meters

over an estimated true width of 13.6 meters from 131 meters, including

over an estimated true width of 0.9 meters from 138 meters

SGRD2349: 5.6 g/t Au

63.1 g/t Au

14.1 g/t Au

2.4 g/t Au

30.2 g/t Au

over an estimated true width of 22.1 meters from 83 meters, including

over an estimated true width of 0.9 meters from 94 meters, and

over an estimated true width of 2.6 meters from 101 meters

over an estimated true width of 18.7 meters from 113 meters, including

over an estimated true width of 0.9 meters from 115 meters

SGRD2363: 4.5 g/t Au

28.4 g/t Au

26.1 g/t Au

12.3 g/t Au

over an estimated true width of 37.4 meters from 79 meters, including

over an estimated true width of 0.9 meters from 103 meters, and

over an estimated true width of 2.6 meters from 107 meters, and

over an estimated true width of 0.9 meters from 122 meters

SGRD2366: 4.4 g/t Au

48.9 g/t Au

over an estimated true width of 20.4 meters from 28 meters, including

over an estimated true width of 0.9 meters from 48 meters

SGRD2367: 4.0 g/t Au

3.7 g/t Au

28.2 g/t Au

over an estimated true width of 6.8 meters from 53 meters

over an estimated true width of 23.8 meters from 72 meters, including

over an estimated true width of 1.7 meters from 97 meters

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SGRD2370: 3.0 g/t Au

15.6 g/t Au

33.5 g/t Au

15.2 g/t Au

over an estimated true width of 31.5 meters from 127 meters, including

over an estimated true width of 0.9 meters from 133 meters, and

over an estimated true width of 0.9 meters from 150 meters, and

over an estimated true width of 0.9 meters from 159 meters,

SGRD2381: 4.2 g/t Au

14.0 g/t Au

11.4 g/t Au

15.1 g/t Au

over an estimated true width of 26.4 meters from 36 meters, including

over an estimated true width of 0.9 meters from 47 meters, and

over an estimated true width of 0.9 meters from 52 meters, and

over an estimated true width of 1.7 meters from 61 meters

An additional 78 drill holes, totaling 1 3,262 meters, have been completed at the Kingfisher Deposit

(refer to Figure 1) as part of the resource confidence infill and extension drill program (refer to Figure

2). Drilling to test the emerging down -plunge potential to the north is advancing with two drill rigs in

operation. Highlights include drill hole SGRD2501 , which intersected 12.7 g/t Au over an estimated

true width of 0.9 meters as part of a wider interval of 1.6 g/t Au over an estimated true width of

9.4 meters from 362 meters depth, approximately 300 meters vertically. This is the deepest drilling to

date at Kingfisher, with mineralization remaining open along strike and at depth along a greater than

one kilometer strike. Drilling is planned to continue through 2025.

The apparent moderate northerly plunge interpreted for the Kingfisher mineralization is atypical for

Séguéla, where a moderate southerly plunge is more common. This variation is interpreted as being

related to localized dextral movement along the main shear corridor.

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Figure 1: Location of the Kingfisher and Sunbird deposits, Séguéla Mine, Côte d’Ivoire

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Figure 2: Kingfisher Deposit long-section - looking west, Séguéla Mine, Côte d’Ivoire

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Sunbird Deposit Drilling Highlights

SGRD2219: 3.0 g/t Au

12.2 g/t Au

37.8 g/t Au

over an estimated true width of 4.2 meters from 410 meters

over an estimated true width of 4.9 meters from 420 meters, including

over an estimated true width of 1.4 meters from 425 meters

SGRD2406: 25.2 g/t Au over an estimated true width of 2.1 meters from 360 meters

SGRD2407: 9.1 g/t Au

52.5 g/t Au

over an estimated true width of 5.6 meters from 196 meters, including

over an estimated true width of 0.7 meters from 199 meters

SGRD2409: 11.2 g/t Au

24.6 g/t Au

over an estimated true width of 5.6 meters from 479 meters, including

over an estimated true width of 2.1 meters from 480 meters

SGRD2427: 4.1 g/t Au

10.4 g/t Au

over an estimated true width of 4.2 meters from 472 meters

over an estimated true width of 4.9 meters from 483 meters

SGRD2431: 8.5 g/t Au

53.3 g/t Au

6.6 g/t Au

21.1 g/t Au

over an estimated true width of 7.0 meters from 566 meters, including

over an estimated true width of 0.7 meters from 566 meters

over an estimated true width of 2.8 meters from 591 meters, including

over an estimated true width of 0.7 meters from 591 meters

SGRD2433: 13.1 g/t Au

26.8 g/t Au

23.2 g/t Au

7.1 g/t Au

10.4 g/t Au

18.2 g/t Au

21.1 g/t Au

over an estimated true width of 3.5 meters from 472 meters, including

over an estimated true width of 0.7 meters from 473 meters, and

over an estimated true width of 0.7 meters from 476 meters

over an estimated true width of 7.7 meters from 482 meters, including

over an estimated true width of 0.7 meters from 482 meters, and

over an estimated true width of 0.7 meters from 484 meters, and

over an estimated true width of 0.7 meters from 487 meters

An additional 41 drill holes, totaling 17,532 meters, have been completed at the Sunbird Deposit (refer

to Figure 1) as part of the resource confidence infill and extension program ( refer to Figure 3). The

program had two objectives : first, to infill and upgrade resource confidence for an approximate

600-meter section along strike of the current underground resource; and second, to extend and expand

the down-plunge extension a further 300 meters south.

Drilling on the main shoot has continued to intersect high grades along the projected plunge, with drill-

defined mineralization now extending more than 1.1 kilometers down plunge , approximately

700 meters below surface. Results include 11.2 g/t Au over an estimated true width of 5.6 meters from

479 meters in drill hole SGRD2409. Results such as 10.4 g/t Au over an estimated true width of

4.9 meters from 483 meters in drill hole SGRD2427 , and 12.2 g/t Au over an estimate true width of

4.9 meters from 420 meters in drill hole SGRD2219, highlight the emergence of a second high grade

shoot extending at least 800 meters down plunge from the bottom of the currently defined pit.

Mineralization remains open at depth and along strike, with drilling scheduled to continue until the end

of 2025.

Drilling targeting the deep extensions also intersected near -surface mineralization approximately

180 meters into the footwall. Further drilling will be carried out to determine the mineralized extent ,

which is presently open over a 400-meter strike length, and relationship to Sunbird as well as historic

small-scale artisanal workings further south along strike. Results include 5.6 g/t Au over an estimated

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true width of 4.9 meters from 98 meters in drill hole SGRD2422 , and 14.7 g/t Au over an estimated

true width of 2.8 meters from 32 meters in drill hole SGRD2218.

Figure 3: Sunbird Deposit long-section - looking west, Séguéla Mine, Côte d’Ivoire

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Quality Assurance & Quality Control (QA - QC)

All drilling was completed under supervision of Fortuna personnel, following standardized procedures

and methodologies.

Reverse Circulation (RC) Drilling

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 sufficient 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 produce

a 12.5% representative sample for laboratory submission. The remaining 87.5% samples were stored

at the drill site until assay results were received and validated. Coarse reject samples from mineralized

samples corresponding to significant intervals are retained and stored on -site at the Company´s core

yard.

Diamond Drilling (DD)

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 for sampling in standard one-meter lengths or

to a geological boundary , then cut into equal halves using a diamond saw. One half was retained 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.

Sample Transport and Analysis

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

preparation laboratory in Yamoussoukro, Cote d’Ivoire or Bureau Veritas ’ preparation and analytical

laboratory in Abidjan, Cote d’Ivoire. Sample pulps prepared by ALS Global were then transported via

commercial courier to ALS Global’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 at

either ALS’s Ouagadougou laboratory or Bureau Veritas’ laboratory in Abidjan. Samples returning

assays >10 ppm Au were reanalyzed using a 50-gram charge and fire assay with a gravimetric finish.

Quality Control

Quality control procedures included systematic insertion of blanks, duplicates , and certified reference

standards into the sample stream. Both ALS Global and Bureau Veritas laboratories also inserted their

own quality control samples.

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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. He has also 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 examining 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:

Carlos Baca | [email protected] | fortunamining.com | X | LinkedIn | YouTube