Antofagasta ignites Centinela mine expansion with new pit

[Redator]

Chilean miner Antofagasta (LON: ANTO) has launched the next phase of its copper growth strategy with the first blast at the Encuentro Sulphides pit at its Centinela mine in the country’s north.

The blast marks the start of initial stripping activities that will supply higher-grade sulphide ore for the Centinela second concentrator, which is at the core of Antofagasta’s $4.4 billion expansion project for the mine.

The ore will complement feed from the existing Esperanza South pit, strengthening Centinela’s production profile. Antofagasta aims to boost its copper output by 30% in the medium term thanks to the expansion, optimizing value from Centinela’s 2.6 billion tonnes of ore reserves.

Approved in July 2025 with an estimated $1-billion investment, the Encuentro Sulphides project is expected to complete its stripping phase by 2028. The deposit, included in Antofagasta’s 2024 year-end reserves, holds about 738 million tonnes grading 0.45% copper, along with by-products of 0.17 g/t gold and 0.015% molybdenum. This compares favourably with Centinela’s broader sulphide reserve grade of 0.41% copper.

The Centinela mining complex, located in Chile’s Antofagasta region, was created in 2014 from the merger of the Esperanza and El Tesoro mines. It produces copper concentrates containing gold and silver through milling and flotation, among other innovative processes.

Powering growth

Once operational, the Encuentro Sulphides pit will serve as the main ore source for Centinela’s second concentrator, which will add 95,000 tonnes per day of processing capacity. The concentrator will use high-pressure grinding rolls and other modern processing technologies to boost efficiency and recovery.

Centinela’s Second Concentrator is expected to begin operations in 2027. At the peak of construction, more than 13,000 people will be employed, supporting local and regional economies. The project will extend Centinela’s operational life by 30 years.

Over its first decade of operation, the facility is projected to produce an average of 170,000 tonnes of copper-equivalent output annually, including about 144,000 tonnes of copper, 130,000 oz of gold, and 3,500 tonnes of molybdenum.

Centinela’s expansion adds a second concentrator and tailings deposit 7 km away, built in two phases. (Image courtesy of Antofagasta.)

The Second Concentrator project also entails major infrastructure upgrades — enhancing Centinela’s raw seawater pumping system, adding new tailings storage facilities, and improving energy and logistics systems. These developments will reinforce operational reliability and sustainability as Centinela ramps up production.

During pre-stripping, roughly 186 million tonnes of material will be moved over two years. The project will progressively introduce autonomous mining equipment, building on the successful use of autonomous haul trucks at Esperanza Sur. Full autonomy is targeted for January 2026.

Smart, sustainable mining

Centinela is recognized as a global leader in innovation. It pioneered large-scale thickened tailings technology and became the first company in Chile to secure permits for depositing tailings in inactive pits. The project has earned awards from the Chilean Association of Consulting Engineers (2022) and the Antofagasta Industrial Association (2025).

RANKED: Top 20 biggest copper mines 2025

The mine also leads in efficient raw seawater use, autonomous operations, and the supply of 100% renewable electricity. With the Second Concentrator, Centinela will nearly double its processing capacity, create jobs, and open new opportunities for local suppliers — strengthening its economic contribution to the Antofagasta Region.

Copper’s momentum

The first blast at the Encuentro pit comes a at peak moment for copper.  Prices surged to a 16-month high in London this week, extending gains to 23% this year as global supply concerns deepen. 

Analysts have trimmed output forecasts following a series of accidents and disruptions at mines in Chile, the Democratic Republic of Congo, and Indonesia, prompting expectations of significant supply deficits.

Worries intensified after Freeport-McMoRan (NYSE: FCX) declared force majeure at its Grasberg mine in Papua, Indonesia — the world’s second-largest copper operation — after severe flooding halted production. The company confirmed over the weekend that all seven missing workers were found dead following the discovery of five additional bodies.