South32 boosts Sierra Gorda ore reserve estimate by 61%

South32, a global diversified metals and minerals company (ASX: S32, LSE: S32, JSE: S32), has increased its Sierra Gorda ore reserve estimate by 61%. This update, announced on Tuesday, July 31 2026, is the result of improved orebody definition following successful infill drilling programs. The company conducted around 85,000 metres of drilling between 2023 and 2025, resulting in an expanded ore reserve estimate of 1,100 million tonnes.

This estimate includes an average of 0.39% total copper, 0.016% total molybdenum, and 0.06 g/t gold, with a copper equivalent grade of 0.46%.

The increase in the ore reserve estimate extends the initial reserve life by approximately five years, reaching 2045. Additionally, the Mineral Resource Estimate (MRE) has also expanded to 1,870 million tonnes, averaging 0.37% total copper, 0.016% total molybdenum, and 0.06 g/t gold, with a copper equivalent grade of 0.44%.

Sierra Gorda is a significant open pit copper mine located in Chile's Antofagasta region. The mine's copper concentrate is transported to ports in Antofagasta and Angamos for international export. South32 CEO Matt Daley highlighted the scale, quality, and extended life of the orebody, stating that it will be a crucial source of copper for decades to come. The update also follows the approval of the fourth grinding line project, which is anticipated to boost copper production by approximately 30% starting in 2031.

The company continues to collaborate with its joint venture partner, KGHM Polska Miedź, to further grow and add value at Sierra Gorda. Sierra Gorda also includes the Catabela Northeast exploration project, where exploration holes have revealed significant copper mineralisation, indicating potential for additional mine life extension.