South32 (ASX:S32) has reported a 61% increase in ore reserve estimates at its Sierra Gorda copper mine in Chile following an extensive 85,000m infill drilling program.
The updated ore reserve estimate, as at 31 July 2026, has increased to 1,100 million tonnes (Mt) averaging 0.39% total copper (Cu), 0.016% total molybdenum (Mo), and 0.06 grams per tonne gold (Au), at a total copper equivalent (CuEq) grade of 0.46%. The previous estimate as at 30 June 2026 stood at 679Mt.
Mine life has also been extended by approximately five years to 2045, incorporating an expanded processing capacity from the approved fourth grinding line project.
Sierra Gorda’s mineral resource estimate totals 1,870Mt averaging 0.37% Cu, 0.016% Mo, and 0.06g/t Au, for a CuEq grade of 0.44%.
CEO Matt Daley says the update highlights the scale and quality of the long-life orebody.
“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,” Daley says.
The fourth grinding line project will expand processing capacity from 135,000 tonnes per day to 165,000 tonnes per day by 2031. Total payable production from 2026 until 2045 is estimated at 3,548,000 tonnes of Cu, 982,000 ounces of Au, and 93,000 tonnes of Mo.
South32 holds a 45% interest in Sierra Gorda alongside joint venture partner KGHM Polska Miedź (55%).
South32 is a metals and mining company focused on developing key commodities like aluminium, base metals, and manganese.
Write to Paula Fabe at Mining.com.au
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