TSX- and ASX-listed Capstone Copper has sanctioned construction of its Mantoverde Optimised (MV-O) project in Chile, following receipt of all required board and regulatory approvals, including the DIA environmental permit in early July.

MV-O is a brownfield expansion of Mantoverde’s sulphide concentrator that will lift throughput from 32 000 t/d to 45 000 t/d, delivering an estimated 20 000 t/y of incremental copper and 6 000 oz/y of gold, while extending the mine life from 19 to 25 years.

“Sanctioning of our MV Optimised project represents a significant milestone on our continued path towards transformational growth,” said CEO Cashel Meagher on Monday. “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."

He said MV-O represented the next phase of Capstone's Mantoverde-Santo Domingo district growth strategy. "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.”

Detailed engineering for MV-O is about 40% complete, which Capstone said had helped derisk the project and improve the accuracy of cost and schedule estimates. The concentrator expansion is expected to take about one year to build, with ramp-up beginning in the fourth quarter of 2026 and full expanded capacity sustained from early 2027.

The company has pegged expansionary capital at $176-million, about $20-million higher than the 2024 feasibility study estimate, mainly owing to scope changes identified during the ramp-up of Mantoverde’s recently commissioned sulphide concentrator. These include cyclone feed pump upgrades, additional pumping and sump capacity, flotation and tailings plant electrical enhancements, and dust suppression measures.

With the sanctioning decision, Capstone has increased its 2025 expansionary capital guidance by $60-million to $120-million, with $70-million of that earmarked for Mantoverde. The remaining $106-million will be spent in 2026.

Mantoverde, located in Chile’s Atacama region, is 70%-owned by Capstone and 30%-owned by Mitsubishi Materials. The mine has produced copper cathode since the 1990s, and in 2023, Capstone completed its Mantoverde Development project to enable sulphide ore processing alongside oxide operations.