25 AUGUST 2026
Updated Ore Reserve and Mineral Resource estimates for the Sierra Gorda copper mine in Chile have been released, including a 61% increase to the Ore Reserve estimate and an extension of the initial reserve life to 2045.
The updates, released in accordance with the JORC Code (2012)1 guidelines, reflect enhanced orebody definition following successful infill drilling programs, with approximately 85,000 metres from 200 drillholes completed between 2023 and 2025.
“This update highlights the scale, quality and long-life orebody at Sierra Gorda, which we expect will be a significant source of copper for decades to come,” said Matt Daley, South32 Chief Executive Officer.
The updated estimates as at 31 July 2026 reflect2:
- a 61% increase in the Ore Reserve estimate to 1,100 million tonnes, averaging 0.39% total copper, 0.016% total molybdenum and 0.06 g/t gold, at a total copper equivalent grade of 0.46%;
- an extension of the initial reserve life3 by approximately five years to 2045; and
- a Mineral Resource estimate of 1,870 million tonnes, averaging 0.37% total copper, 0.016% total molybdenum and 0.06 g/t gold, at a total copper equivalent grade of 0.44%.
Full details of the updates are available in the exchange release (.pdf).Sierra Gorda is a large, conventional, open pit copper mine located in the Antofagasta region of northern Chile. South32 acquired a 45% interest in Sierra Gorda in February 2022 and has joint control alongside 55% joint venture partner KGHM Polska Miedź.
This update follows the approval in July to proceed with execution of the fourth grinding line project at Sierra Gorda, which is expected to increase copper production by approximately 30 per cent from 2031.
“With the current orebody remaining open at depth, the mine offers potential for further growth beyond today’s increase to ore reserve and reserve life,” said Matt.
“We continue to work with our joint venture partner to drive further growth and value at Sierra Gorda. This includes the Catabela Northeast exploration project, where exploration holes have intersected significant copper mineralisation, highlighting the potential for future mine life extension.”
1 Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, 2012 edition. Ore Reserve and Mineral Resource estimates are reported on a 100% basis.
2 Compared to 30 June 2026. Refer to Annexure 1 of this announcement.
3 Includes expanded processing capacity from the fourth grinding line project.