Fortuna delivers Feasibility Study for Diamba Sud: 60% IRR, US$1bn NPV5% at US$3,500/oz

(All financial information contained herein are expressed in US dollars unless otherwise stated) VANCOUVER, British Columbia, June 29, 2026 (GLOBE NEWSWIRE) -- Fortuna Mining Corp. (NYSE: FSM | TSX: FVI) announces positive results from the feasibility study (“FS”) for its Diamba Sud Gold Project in Senegal, confirming an economically robust open-pit conventional carbon-in-leach (“CIL”) gold mine and advancing one of Fortuna’s key growth opportunities. Jorge A. Ganoza, President and CEO of Fortuna, commented, “Diamba Sud is a standout growth project with high returns, fast payback, and is expected to be our lowest-cost mine. Together with our Séguéla mine expansion, Diamba Sud supports our plan to grow our annual gold production rate by approximately 60% to more than 500,000 ounces in 2028.” Mr. Ganoza concluded, “With the recent receipt of the environmental decree from the Senegalese government and the feasibility study complete, we are ready to move Diamba Sud toward a final investment decision upon completion of the mining permit process.” Feasibility Study Highlights Financial After-tax NPV 5% of $1 billion, IRR of 60%, and 1-year payback at $3,500/oz gold At $4,000/oz gold, returns increase to NPV 5% of $1.3 billion, IRR of 72%, and 11-month payback Production and Cost Strong first 4 years : Average annual gold production of 158,000 ounces 9.4-year life of mine (“LOM”) with an average annual gold production of 116,000 ounces Low-cost profile : Average AISC 1 of $1,056/oz over the first 4 years and $1,332/oz over LOM Final investment decision expected after receipt of the mining permit; first gold targeted by Q2 2028 CAPEX and Funding Total initial capital of $397.5 million Funding secured by the Company's strong cash flow genera