South32 Increases Sierra Gorda Copper Reserve by 61%

South32 reported a 61% increase in the ore reserve estimate for its Sierra Gorda copper mine in Chile. The company announced the updated figures on Tuesday, with estimates current as of July 31, 2026. This update raises the mine’s ore reserve to 1,100 million tonnes.

The new estimate means the mine’s life will extend by about five years, now reaching 2045. The ore averages 0.39% total copper, 0.016% total molybdenum, and 0.06 g/t gold. This gives a total copper equivalent grade of 0.46%.

South32 also updated its mineral resource estimate (MRE) to 1,870 million tonnes. This MRE averages 0.37% total copper, 0.016% total molybdenum, and 0.06 g/t gold, with a copper equivalent grade of 0.44%. The company said the updates came after successful infill drilling programs from 2023 to 2025, completing about 85,000 meters from 200 drillholes.

Sierra Gorda is an open pit copper mine located in northern Chile’s Antofagasta region. South32 CEO Matt Daley stated the mine will be a significant source of copper for decades. A fourth grinding line project, approved in July, is expected to increase copper production by about 30% starting in 2031.

South32 holds a 45% interest in Sierra Gorda, acquired in February 2022. It jointly controls the mine with KGHM Polska Miedź, which owns the remaining 55%.