South32 has reported a sharp drop in silver output from its Cannington mine in north-west Queensland, one of the world’s largest silver and lead operations. According to the company’s September 2026 quarterly report, Cannington produced 1,808 koz of silver in the three months to 30 September, down 13% on the same quarter last year and 28% lower than the June quarter.
Paste fill bottleneck behind the fall
South32 linked the weaker result to a temporary reduction in paste backfill availability, which delayed access to planned stopes. With less ore coming from the planned areas, mined volumes and grades fell and the mill was topped up with lower grade stockpiles. Silver grade processed slipped to 118 g/t, compared with 148 g/t a year earlier, and silver sales fell 10% year on year to 1,934 koz.
Guidance held as upgrades roll out
Management did not change Cannington’s FY27 guidance, which is expressed in zinc equivalent terms, and said upgrades to paste delivery should support higher mining rates later in the financial year. Elsewhere in the portfolio, the company’s 45% share of Sierra Gorda in Chile lifted silver production to 253 koz. The quarter adds context to the strategic shift we covered in our look at South32 and negative treatment charges.
What it means for ASX silver investors
Cannington is a meaningful source of mined silver, so an extended shortfall there tightens the supply picture that The Silver Institute tracks closely. For investors, the key question is whether the paste fill fix arrives on schedule. A recovery in the second half would reassure, while further delays could put pressure on South32’s cost profile. The result also keeps attention on emerging Australian silver developers, including those covered in our recent Silver Mines Bowdens royalty update and wider silver mining news.
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