Mr. Cashel Meagher reports

CAPSTONE COPPER ANNOUNCES SALE OF COZAMIN FOR TOTAL CONSIDERATION OF UP TO $385 MILLION

Capstone Copper Corp. has entered into a definitive agreement to sell its Cozamin copper-silver-zinc-lead mine, located in Zacatecas, Mexico, to Luca Mining Corp. for up to $385-million in total consideration. Unless otherwise stated, all numbers are presented in U.S. dollars.

Under the terms of the transaction, Capstone will receive total consideration of up to $385-million, comprising:

• $275-million in upfront cash, subject to customary closing adjustments;
• $15-million in Luca shares, to be issued to Capstone at closing;
• $35-million in deferred consideration, to be received on the first anniversary of closing;
• Up to $60-million in contingent cash consideration tied to annual average copper prices.

Net proceeds from the transaction will strengthen the company's balance sheet and provide financial flexibility to support its growth pipeline.

Cashel Meagher, Capstone's president and chief executive officer, commented: "Cozamin has been an important part of our portfolio, providing stability and strong cash flows as Capstone has matured into a diversified copper producer. Since its first full year of operations in 2007, Cozamin has delivered consistently strong performance, a testament to the capability and quality of the team. We extend our sincere thanks to everyone at Cozamin for their dedication to safety and operational excellence over this period. We believe Cozamin will be well positioned under Luca's ownership, providing regional expertise, focus, and commitment to invest in the mine's future for the long-term benefit of the work force and the surrounding communities.

"The transaction optimizes our portfolio and further strengthens our balance sheet, enabling us to redeploy capital into our high-return growth projects and allowing leadership to focus on the opportunities we believe will create the most value for our shareholders. It is an ideal time to streamline our portfolio through this divestiture as we advance towards transformational copper growth in Chile and the United States.

"We are also pleased to retain exposure to the exploration upside at Cozamin, through our shareholding in Luca, following completion of the transaction. Given the strong operational track record of the Luca team in Mexico, we believe they will be excellent stewards of the mine and are well placed to unlock its full potential."

Indicative timeline and approvals

The transaction is expected to close in the fourth quarter of 2026, subject to the completion of customary conditions and regulatory approvals, including stock exchange and Mexican National Antitrust Commission approval. The transaction is not subject to shareholder approval or any financing conditions.

Advisers

Scotiabank is acting as exclusive financial adviser to Capstone. Blake, Cassels & Graydon LLP is acting as Canadian legal counsel to Capstone, and Creel, Garcia-Cuellar, Aiza y Enriquez SC is acting as Mexican legal counsel to Capstone.

About Luca Mining Corp.

Luca is a Canadian mining company with two wholly owned mines located in the prolific Sierra Madre mineralized belt in Mexico. These mines produce gold, silver, zinc, copper and lead and generate strong cash flow. Both mines have considerable development and resource upside as well as district-scale exploration potential.

Luca's Campo Morado mine hosts VMS-style (volcanogenic massive sulphide), polymetallic mineralization within a large land package comprising 121 square kilometres. It is an underground operation, producing zinc, copper, gold, silver and lead. The mine is located in Guerrero state.

Luca's Tahuehueto mine is a large property of over 100 square kilometres in Durango state. The project hosts epithermal gold and silver vein-style mineralization. Tahuehueto is a newly constructed underground mining operation producing primarily gold and silver. Luca has successfully commissioned its mill and is now in commercial production.

About Capstone Copper Corp.

Capstone Copper is an Americas-focused copper mining company headquartered in Vancouver, Canada. Capstone's operating portfolio of assets includes the Pinto Valley copper mine, located in Arizona, United States; the Cozamin copper-silver-zinc-lead mine, located in Zacatecas, Mexico; the Mantos Blancos copper-silver mine, located in the Antofagasta region, Chile; and the Mantoverde copper-gold mine, located in the Atacama region, Chile. Capstone's growth pipeline includes the fully permitted Santo Domingo copper-iron-gold project, located approximately 35 kilometres northeast of Mantoverde in the Atacama region, Chile, as well as a portfolio of exploration properties in the Americas.

Capstone Copper's strategy is to unlock transformational copper production growth while executing on cost and operational improvements through innovation, optimization, and safe and responsible production throughout the company's portfolio of assets. Capstone Copper focuses on profitability and disciplined capital allocation to surface stakeholder value. Capstone Copper is committed to creating a positive impact in the lives of its people and local communities while delivering compelling returns to investors by responsibly producing copper to meet the world's growing needs.

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