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Fortuna obtains key environmental approval for Diamba Sud Gold Project in Senegal

Permits & Approvals

NEWS RELEASE

Fortuna obtains key environmental approval for Diamba Sud Gold

Project in Senegal

Vancouver, British Columbia, June 15, 20 26: Fortuna Mining Corp . (NYSE: FSM |

TSX: FVI) announces that the Company has received the environmental decree from

Senegal’s Ministry of Environment and Ecological Transition approving the Environmental

and Social Impact Assessment for the Diamba Sud Gold Mine. This authorization certifies

that the project complies with all applicable environmental regulations and has been socially

accepted by the project’s stakeholders. It marks a decisive step towards obtaining the mining

permit following the submission of its application t o the Ministry of Energy, Petroleum, and

Mines on February 4, 2026.

Jorge A. Ganoza, President and CEO, commented, “Obtaining the environmental permit for

our future Diamba Sud Gold Mine, just nine months from submission to approval, is a clear

testament to the quality of our work and demonstrates that mining projects in Senegal can

advance on a highly competitive timel ine. This milestone also reflects the Government of

Senegal’s commitment to enabling the responsible development of its mining sector .”

Mr. Ganoza continued, “ With this key approval in hand, we will continue advancing early

construction works as we move toward the important milestones of completing the feasibility

study, followed by a final construction decision in mid-2026.”

About Diamba Sud Gold Project, Senegal

The Diamba Sud Gold Project is in the late stages of permitting and feasibility. A Preliminary

Economic Assessment (“PEA”) outlined robust project economics (refer to Fortuna news

release dated October 15, 2025, “Fortuna delivers robust PEA for Diamba Sud Gold Project

in Senegal: After-tax IRR of 72% and NPV5% of US$563 million using US$2,750 per ounce”).

Early works are underway, including camp construction and the placement of purchase

orders for critical-path equipment packages. The 2026 project budget is US$100 million, with

a final investment and construction decision anticipated by mid-2026.

The PEA is preliminary in nature and includes inferred mineral resources that are considered too

speculative geologically to have the economic considerations applied to them that would enable them

to be categorized as mineral reserves; as such, there is no certainty that the PEA results will be

realized. Mineral resources that are not mineral reserves do not have demonstrated economic

viability1.

Note:

1. Refer to the table in Appendix 2 on page 5 of this release for a summary of the PEA’s key assumptions, operational parameters and economic results and values.

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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, Guinea, Guyana, 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 | Instagram | TikTok

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Forward looking Statements

This news release contains forward -looking statements which constitute “forward -looking information” within the

meaning of applicable Canadian securities legislation and “forward-looking statements” within the meaning of the

“safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 (collectively, “Forward -looking

Statements”). All statements included herein, other than statements of historical fact, are Forward -looking

Statements and are subject to a variety of known and unknown risks and uncertainties which could cause actual

events or results to differ materially from those reflected in the Forward-looking Statements. The Forward-looking

Statements in this news release may include, without limitation, statements about the Company’s plans for the

development of the Diamba Sud Gold Project, including the timing of a final investment and construction decision

which is targeted for mid-2026, and is subject to the receipt of all required permits, including an exploitation permit,

the delivery of a feasibility study; the continued advancement of an early works program including camp

construction the placement of purchase orders for critical-path equipment packages and the estimated amount of

that program; the estimated project economics for Diamba Sud as reflect in the PEA ; statements about the

Company’s business strategies, plans and outlook; the Company’s plans for its mines and mineral properties;

changes in general economic conditions and financial markets; the impact of inflationary pressures on the

Company’s business and operations; the future results of exploration activities; expectations with respect to metal

grade estimates and the impact of any variations relative to metals grades experienced; assumed and future

metal prices ; the merit of the Company’s mines and mineral properties; and the future financial or operating

performance of the Company; the Company’s ability to comply with contractual and permitting or other regulatory

requirements; and approvals and other matters. Often, but not always, these Forward-looking Statements can be

identified by the use of words such as “estimated”, “potential”, “open”, “future”, “assumed”, “projected”, “proposed”,

“used”, “detailed”, “has been”, “gain”, “planned”, “reflecting”, “will” , “anticipated”, “estimated” “containing”,

“remaining”, “to be”, or statements that events, “could” or “should” occur or be achieved and similar expressions,

including negative variations.

Forward-looking Statements involve known and unknown risks, uncertainties and other factors which may cause

the actual results, performance, or achievements of the Company to be materially different from any results,

performance or achievements expressed o r implied by the Forward-looking Statements. Such uncertainties and

factors include, among others, operational risks associated with mining and mineral processing; uncertainty

relating to Mineral Resource and Mineral Reserve estimates; uncertainty relating to capital and operating costs,

production schedules and economic returns; risks relating to the Company’s ability to replace its Mineral

Reserves; risks related to the conversion of Mineral Resources to Mineral Reserves; risks associated with mineral

exploration and project development; uncertainty relating to the repatriation of funds as a result of currency

controls; environmental matters including obtaining or renewing environmental permits and potential liability

claims; uncertainty relating to nature and climate conditions; laws and regulations regarding the protection of the

environment (including greenhouse gas emission reduction and other decarbonization requirements and the

uncertainty surrounding the interpretation of omnibus Bill C -59 and the related amendments to the C ompetition

Act (Canada); risks associated with political instability and changes to the regulations governing the Company’s

business operations; changes in national and local government legislation, taxation, controls, regulations and

political or economic developments in countrie s in which the Company does or may carry on business; risks

associated with war, hostilities or other conflicts, such as the Ukrainian – Russian, and Israeli – Hamas and Iran

– Israel and United States conflicts, and the impacts they may have on global eco nomic activity; risks relating to

the termination of the Company’s mining concessions in certain circumstances; developing and maintaining

relationships with local communities and stakeholders; risks associated with losing control of public perception as

a result of social media and other web -based applications; potential opposition to the Company’s exploration,

development and operational activities; risks related to the Company’s ability to obtain adequate financing for

planned exploration and development activities; property title matters; risks related to the ability to retain or extend

title to the Company’s mineral properties; risks relating to the integration of businesses and assets acquired by

the Company; impairments; risks associated with climate change legislation; reliance on key personnel; adequacy

of insurance coverage; operational safety and security risks; legal proceedings and potential legal proceedings;

uncertainties relating to general economic conditions; risks relating to a global pandemic, which could impact the

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Company’s business, operations, financial condition and share price; competition; fluctuations in metal prices;

risks associated with entering into commodity forward and option contracts for base metals production;

fluctuations in currency exchange rates and interest rates; tax audits and reassessments; risks related to hedging;

uncertainty relating to concentrate treatment charges and transportation costs; sufficiency of monies allotted by

the Company for land reclamation; risks associated with dependence upon information technology systems, which

are subject to disruption, damage, failure and risks with implementation and integration; labor relations issues; as

well as those factors discussed under “Risk Factors” in the Company's Annual Information Form for the fiscal year

ended December 31, 2025. Although the Company has attempted to identify important factors that could cause

actual actions, events, or results to differ materially from those described in Forward -looking Statements, there

may be other factors that cause actions, events or results to differ from those anticipated, estimated or intended.

Forward-looking Statements contained herein are based on the assumptions, beliefs, expectations and opinions

of management, including, but not limited to, the accuracy of the Company’s current Mineral Resource and Mineral

Reserve estimates; that the Company’s activities will be conducted in accordance with the Company’s public

statements and stated goals; that there will be no material adverse change affecting the Company, its properties

or its production estimates (which as sume accuracy of projected ore grade, mining rates, recovery timing, and

recovery rate estimates and may be impacted by unscheduled maintenance, labor and contractor availability and

other operating or technical difficulties); the duration and effect of gl obal and local inflation; the duration and

impacts of geo-political uncertainties on the Company’s production, workforce, business, operations and financial

condition; the expected trends in mineral prices, inflation and currency exchange rates; that all required approvals

and permits will be obtained for the Company’s business and operations on acceptable terms; that the economics

of the Diamba Sud PEA remain consistent; that project costs and expenses will remain consistent; that there will

be no significant disruptions affecting the Company's operations and such other assumptions as set out herein.

Forward-looking Statements are made as of the date hereof and the Company disclaims any obligation to update

any Forward-looking Statements, whether as a resul t of new information, future events, or results or otherwise,

except as required by law. There can be no assurance that these Forward -looking Statements will prove to be

accurate, as actual results and future events could differ materially from those antic ipated in such statements.

Accordingly, investors should not place undue reliance on Forward-looking Statements.

Cautionary Note to United States Investors Concerning Estimates of Reserves and Resources

All reserve and resource estimates included in this news release have been prepared in accordance with National

Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") and the Canadian Institute of Mining,

Metallurgy, and Petroleum Definition Standards on Mineral Resources and Mineral Reserves. NI 43-101 is a rule

developed by the Canadian Securities Administrators that establishes standards for public disclosure by a

Canadian company of scientific and technical information concerning m ineral projects. All Mineral Reserve and

Mineral Resource estimates contained in the technical disclosure have been prepared in accordance with NI 43-

101 and the Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards on Mineral Resources

and Reserves. Canadian standards, including NI 43 -101, differ from the requirements of the Securities and

Exchange Commission, and mineral reserve and resource information included in this news release may not be

comparable to similar information disclosed by U.S. companies.

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Appendix 2: PEA Key Highlights

Metrics Units Results

Gold price $/oz 2,750

Life of mine years 8.1

Processing Duration years 7.9

Total mineralized material mined1 kt 17.8

Contained gold in mineralized material mined1 koz 932

Strip ratio Waste: mineralized material 5.5:1

Throughput initial 3 years (primarily oxide) Mtpa 2.5

Throughput after 3 years (primarily fresh) Mtpa 2.0

LOM grade g/t 1.63

Recoveries % 90

Gold production

Total Production over LOM koz 840

Average annual production over LOM koz 106

Average annual production over first 3 years koz 146

Per unit costs LOM

Mining $/t, mined 4.82

Processing $/t, processed 13.9

G&A $/t, processed 6.7

Cash costs1

Average operating cash costs2over LOM $/oz 1,081

Average operating cash costs2 over first 3 years $/oz 759

AISC1

Average AISC2over LOM $/oz 1,238

Average AISC2 over first 3 years $/oz 904

Capital costs

Initial capital expenditure $ M 283

Sustaining capital expenditure + Infrastructure (includes closure costs) $ M 48

Returns

NPV5%, pre-tax (100% Project basis) $ M 772

Pre-tax IRR % 86

NPV5%, after-tax (100% Project basis) $ M 563

After-tax IRR % 72

After Tax Payback Period years 0.8

Annual EBITDA 2

Average EBITDA2 over LOM $ M 167

Average EBITDA2 over first 3 years $ M 277

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Notes:

1. The pit optimization shells used for the mine plan were generated using a gold price of $2,300 per ounce.

2. This is a non-IFRS financial measure. The definition and purpose of this non -IFRS financial measure is included in the Company’s management’s discussion and

analysis for the year ended December 31, 2025, under the heading “Non-IFRS Financial Measures”. Non-IFRS financial measures have no standardized meaning

under IFRS and therefore, may not be comparable to similar measures presented by other issuers.

3. Average operating cash costs and average AISC represent costs for projected production for the LOM at the time of gold sales.

4. The PEA is presented on a 100 percent project basis. However, upon the granting of the exploitation permit, the Senegalese Government is entitled to a 10 percent

free-carried interest in Boya, with the right for the State to acquire an additional contributory interest of up to 25 percent.

5. The economic analysis was carried out using a discounted cash flow approach on a pre-tax and after-tax basis, based on the gold price of $2,750/oz.

6. The IRR on total investment that is presented in the economic analysis was calculated assuming a 100% ownership in Diamba Sud.

7. The NPV was calculated from the after-tax cash flow generated by the Project, based on a discounted rate of 5% and an effective date of October 10, 2025.

8. The PEA assumes that the percentage of certain royalties and taxes payable to the State, the percentage of the investment tax credit available to the company and

the percentage payable to the social development fund will be in accordance with the provision s of the Mining Convention between Boya S.A. and the State of

Senegal dated April 8, 2015. It should be noted, however, that the State retains the sovereign prerogative to review or revisit certain fiscal terms during the exploitation

permit approval process, and as such, the current framework may be subject to amendment.

9. The PEA is preliminary in nature, and it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations

applied to them that would enable them to be categorized as mineral reserves, and, as such, th ere is no certainty that the PEA results will be realized. Mineral

resources that are not mineral reserves do not have demonstrated economic viability.

10. Further information regarding the PEA, including details on key assumptions, parameters, opportunities, risks and other factors are contained in the Technical Report

prepared for the Company entitled “Diamba Sud Gold Project, Kedougou Region, Senegal” wit h an effective date of October 15, 2025, which has been filed on

SEDAR+ and on EDGAR under the Company’s profile.