Capstone estimates that construction at the MV Optimised sulphide concentrator expansion will take around one year.
The Mantoverde project, located in Chile's Atacama region, is 70% owned by Capstone Copper and 30% by Mitsubishi Materials. The MV Optimised initiative represents a major expansion of the Mantoverde sulphide concentrator, aiming to increase throughput from 32,000 to 45,000 tonnes per day (tpd). This will result in an additional annual production of approximately 20,000 tonnes of copper and 6,000 ounces of gold. The expansion will also extend the mine's life from 19 to 25 years.
To support this growth, Capstone will upgrade the existing process infrastructure at Mantoverde. This includes debottlenecking the current system and acquiring additional mining and processing equipment to meet the expanded throughput.
Capstone CEO Cashel Meagher commented: “Sanctioning of our MV Optimised 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.”
Since the 1990s, Mantoverde has been producing copper cathodes from its solvent extraction-electrowinning (SX-EW) plant. In June 2024, the first saleable copper concentrate was produced, and commercial production began in September 2024. By Q2 2025, the plant had already exceeded its design capacity, achieving an average throughput of 33,409 tpd.
Capstone estimates that the construction of the MV Optimised sulphide concentrator expansion will take about one year, with a ramp-up period extending into Q4 2026. The company expects the new sulphide throughput capacity of 45,000 tpd to be sustainable starting in early 2027.
With detailed engineering now 40% complete, Capstone has de-risked the project, providing greater certainty on timelines and capital expenditure estimates. The total capital cost for the expansion is projected at $176 million (C$242.28 million), which includes upgrades to the concentrator processing plant, mining equipment, infrastructure improvements, and desalination plant enhancements.
Capstone has revised its 2025 capital guidance upwards by $60 million, bringing the total expansionary capital for Mantoverde to $70 million and consolidated capital to $120 million. The remaining $106 million is expected to be spent in 2026. Additionally, the company increased its senior notes offering to $600 million in March, with a 6.75% annual interest rate and notes due in 2033, secured by the company's subsidiaries.
