Mr. Cashel Meagher reports

CAPSTONE COPPER ANNOUNCES SANCTIONING OF MANTOVERDE OPTIMIZED PROJECT

Capstone Copper Corp.'s Mantoverde Optimized (MV Optimized or MV-O) project has been sanctioned for construction following all required board approvals. All amounts in this news release are in U.S. dollars, unless otherwise noted.

MV Optimized is a capital-efficient brownfield expansion of Mantoverde's sulphide concentrator, increasing throughput from 32,000 to 45,000 ore tonnes per day, providing incremental copper and gold production of approximately 20,000 tonnes and 6,000 ounces per annum, respectively, and extending the mine life from 19 to 25 years.

Cashel Meagher, Capstone's chief executive officer, commented: "Sanctioning of our MV Optimized project represents a significant milestone on our continued path towards transformational growth. With the required board and regulatory approvals in hand, we will now commence construction on our capital-efficient, quick-payback and high-return expansion project at Mantoverde. MV Optimized represents the next phase of our Mantoverde-Santo Domingo district growth strategy, which aims to expand our world-class mining district in Chile with significant copper production and very attractive unit costs. Our team is committed to responsible production and ongoing engagement with stakeholders as we progress our growth plans to meet the growing global requirements for copper."

Advancing the path toward transformational growth

The MV Optimized project is now formally sanctioned for development following receipt of the DIA environmental permit in early July. MV Optimized involves an expansion of Mantoverde's sulphide concentrator to increase throughput from 32,000 to 45,000 ore tonnes per day. The current process infrastructure at Mantoverde can sustain up to 45,000 ore tonnes per day by debottlenecking minor components of the plant. To support the expanded mining and processing rates, certain mining equipment and plant equipment additions are required.

The company has advanced the level of detailed engineering to approximately 40-per-cent completion, derisking the project and increasing the degree of certainty in timelines and expansionary capital estimates. Expectations have been updated from those outlined within the MV-O 2024 feasibility study to reflect date of sanctioning, key learnings from the ramp-up of the new Mantoverde sulphide concentrator, and the increased level of detailed engineering.

Capstone estimates that the MV Optimized sulphide concentrator expansion construction will require approximately one year, followed by a ramp-up period in Q4 2026. The expanded sulphide throughput capacity of approximately 45,000 ore tonnes per day is expected to be sustained starting in early 2027. The company expects the construction and ramp-up of the oxide leach optimization to require an additional quarter, with higher cathode production starting in Q2 2027.

MV Optimized expansionary capital cost estimate

The updated total expansionary capital cost for MV Optimized has been estimated at $176-million, as shown in the following table, reflecting a refined and optimized scope. Approximately $20-million of the capital cost increase from the previous estimate is attributable to scope changes based on learnings from the recent ramp-up of the Mantoverde sulphide concentrator. These scope changes include cyclone feed pump capacity upgrades in the grinding circuit, increased pump, sump and electrical room capacity in the flotation and tailings management areas, and minor additional environmental commitments, notably for dust suppression. The remainder of the increase largely reflects modest inflation identified through advanced detailed engineering since the date of the feasibility study.

The total capital intensity of the MV Optimized project remains extremely competitive at approximately $9,000 per tonne of incremental annual copper equivalent production. The estimated capital cost encompasses:

• Additional mining equipment required to support the expanded mining and processing rate;
• Additional and/or upgrades to concentrator processing plant equipment to debottleneck the plant;
• Infrastructure for improved heap and dump management, plus the conversion of the dynamic heap to a bioleach facility to extract sulphide-based copper;
• Upgrades to the desalination plant to ensure a stable flow of the required water for MV Optimized;
• Includes a contingency of approximately 8 per cent.

2025 consolidated capital expenditure guidance

With the sanctioning decision for MV-O, the company has increased its expansionary capital guidance for 2025 by $60-million, bringing total 2025 Mantoverde expansionary capital expenditure guidance to $70-million, and total consolidated expansionary capital guidance to $120-million. The remaining MV-O expansionary capital of $106-million is expected to be spent in 2026. For more detailed guidance, see the company's press release dated Jan. 20, 2025.

Mantoverde operation summary

Mantoverde (70 per cent owned by Capstone Copper and 30 per cent owned by Mitsubishi Materials Corp.) is an open-pit copper-gold mine located in the Atacama region of Chile. Since the 1990s, Mantoverde operated as an oxide mine producing copper cathodes from its 60,000-tonne-per-annum capacity SX/EW (solvent extraction/electrowinning) plant. In 2023, Capstone Copper completed construction of the Mantoverde development project (MVDP), which enabled the mine to process its copper sulphide reserves, in addition to existing oxide reserves. The MVDP involved the addition of a sulphide concentrator and tailings storage facility, and the expansion of the existing desalination plant and other minor infrastructure. First saleable copper concentrate at MVDP was produced in June, 2024, and commercial production was achieved in September, 2024. In Q2 2025, the plant achieved an average throughput of 33,409 tonnes per day, exceeding its current design capacity.

For further details, please see the press release dated Oct. 1, 2024, announcing the results of the Mantoverde Optimized feasibility study.

Qualified persons

Peter Amelunxen, PEng, senior vice-president, technical services of Capstone Copper, a qualified person as defined by National Instrument 43-101, reviewed and approved the content of this news release that is based on the 2024 technical report.

About Capstone Copper Corp.

Capstone Copper is an Americas-focused copper mining company headquartered in Vancouver, Canada. The company owns and operates the Pinto Valley copper mine located in Arizona, United States, the Cozamin copper-silver mine located in Zacatecas, Mexico, the Mantos Blancos copper-silver mine located in the Antofagasta region, Chile, and 70 per cent of the Mantoverde copper-gold mine, located in the Atacama region, Chile. In addition, the company owns the fully permitted Santo Domingo copper-iron-gold project, located approximately 30 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. The company focuses on profitability and disciplined capital allocation to surface stakeholder value. The company 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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