Fortuna Mining Corp. (NYSE: FSM) (TSX: FVI) is pleased to announce that it has approved the expansion of its Séguéla Gold Mine in Côte d’Ivoire.

The project includes an expansion of the Séguéla processing facility, upgrades to supporting infrastructure, and development of the Sunbird underground mine. Together, these investments are expected to increase throughput, improve gold recoveries, accelerate production from Séguéla’s growing resource base, and reinforce the mine’s position as a cornerstone asset in Fortuna’s portfolio.

Expansion Highlights

• 30% increase in processing capacity, from 1.75 Mtpa to 2.3 Mtpa, with average gold recovery expected to reach 94.5%
• Expected to support average annual gold production at Séguéla of more than 200,000 ounces over the next decade
• Higher recoveries and accelerated gold production are expected to enhance cash flow generation and deliver attractive project returns, with a projected payback period of approximately 2.5 years
• Estimated construction capital of $109 million, to be funded from operating cash flow and supported by the Company’s strong liquidity of approximately $800 million as of the end of
  Q1 2026

Jorge A. Ganoza, President and CEO, commented, “Séguéla has consistently exceeded expectations since entering production in mid-2023 and continues to demonstrate strong growth potential. This expansion represents the logical next step in unlocking additional value from the asset by increasing processing capacity, integrating underground production, and enhancing operating flexibility. The project supports our strategy of disciplined reinvestment in high-quality assets and, along with the feasibility stage Diamba Sud project in Senegal, advances Fortuna’s objective of increasing consolidated annual gold rate of production toward 500,000 ounces by 2028.”

Project Overview

The Séguéla expansion is designed to increase processing capacity, improve gold recoveries, and support a higher long-term production profile by integrating the Sunbird underground mine with targeted upgrades to the processing plant and supporting infrastructure, including expanded camp facilities and enhancements to the power and water supply systems. Together, these investments are expected to enhance operational flexibility, strengthen cash flow generation, and provide a scalable platform for future growth at Séguéla.

The processing plant expansion will increase throughput from 1.75 Mtpa to approximately 2.3 Mtpa by leveraging existing infrastructure while adding capacity in key areas of the plant. This design is expected to optimize capital efficiency, reduce execution complexity, minimize disruption to ongoing operations during construction and tie-ins, and maintain operational flexibility while supporting future production growth.

Key elements of the processing plant expansion include:

• Comminution upgrades: Retention of the existing crushing circuit and conversion of the milling circuit from a single-stage SAG configuration to a SAG and ball mill circuit, increasing throughput while maintaining the target grind size.
• Gravity and leaching enhancements: Installation of a new gravity circuit, intensive leach reactor, pre-leach thickener, and second carbon-in-leach train to increase leaching capacity and support average gold recoveries of approximately 94.5%.
• Supporting infrastructure upgrades: Enhancements to reagent handling and storage, oxygen supply, process water, plant air, and tailings pumping systems to support the expanded processing rate.

Execution Timeline

Fortuna plans to advance the Séguéla expansion through a phased execution plan designed to minimize disruption to ongoing operations.

Key milestones include:

• H2 2026: Expected commencement of construction activities, including site preparation, camp expansion, procurement of long-lead items, and advancement of EPCM activities.
• Q2 2027: Expected commencement of underground mining at the Sunbird deposit.
• H2 2028: Targeted ramp-up to the expanded processing plant throughput of approximately 2.3 Mtpa.

Qualified Person

Raul Espinoza, Director of Technical Services for Fortuna Mining Corp., is a Fellow and Chartered Professional of the Australasian Institute of Mining and Metallurgy (FAusIMM CP) and a Qualified Person as defined by National Instrument 43-101, Standards of Disclosure for Mineral Projects.
Mr. Espinoza has reviewed and approved the scientific and technical information contained in this news release and has verified the underlying data.

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.