Mining company Antofagasta has approved the construction of a second concentrator plant at its Centinela copper mine in Chile.

With the approval in place, which comes after a review, the company plans to immediately start critical path works. Full construction will begin after finalisation of definitive project finance documents in the first quarter of next year.

This project will be backed by direct financing from Centinela’s shareholders, Antofagasta and Marubeni, which will contribute around 40% of the overall costs, and funds from lenders.

The second concentrator will be built in two phases. Work on the second phase will begin only when the first phase of the project is operational.

When built, the second Centinela concentrator plant can produce an additional 170,000 copper equivalent tonnes per annum (tpa).

The production will include 144,000 tonnes (t) of copper, 130,000oz of gold and 3,500t of molybdenum. With an ore reserve of around two billion tonnes, the mine life of Centinela is expected to be around 36 years.

The project’s current cost estimate is around $4.4bn, up from the previous $3.7bn announced in August 2022.

This investment will be used for the new 95,000tpd concentrator plant, featuring HPGRs for reduced energy usage.

The company will also invest in expanding the existing raw seawater pumping and transport system, and a new facility for tailings storage.

It will also expand outbound logistics networks such as the concentrate transport system and critical port infrastructure, additional loading equipment and autonomous hauling equipment.

Camps and ancillary civil infrastructure were designed to fully integrate with existing operations at the location to prevent redundancy.

The ore for the second concentrator will be initially sourced from the recently opened Esperanza Sur pit, followed by the Encuentro pit.

The sulphide ore in the Encuentro pit is located beneath the Encuentro Oxides reserves, which are projected to be depleted by 2026.

Antofagasta CEO Iván Arriagada said: “The Centinela Second Concentrator Project is a key element of our profitable growth strategy as it will add a further 170,000 copper equivalent tonnes per year of production, with first copper expected in 2027, significantly progressing us towards our long-term ambition of 900,000t of profitable copper production.

“Importantly, it will also reduce net cash costs and unlock significant value in the Centinela District’s two-billion-tonne ore reserve. This brownfield expansion project is expected to deliver attractive returns in excess of our cost of capital at a wide range of commodity prices. We are leveraging more than 20 years of operational experience and understanding of Centinela’s ores, utilising existing infrastructure and building on long-established relationships within our local communities.”