Mining company South32 has initiated a phased mining restart at its Groote Eylandt manganese operation (Gemco) and expects first production from the primary concentrator during the December quarter.

Gemco, in which South32 holds a 60% stake in partnership with Anglo American, faced significant damage from Cyclone Megan, which struck the Northern Territory in March, resulting in a suspension of production.

In its first quarter production report for 2025, South32 highlighted progress in a substantial dewatering programme and ongoing investments in mine repairs and infrastructure. Gemco also received initial external insurance recoveries amounting to $100-million during the first quarter.

The suspension of Australian manganese production has notably impacted South32’s overall output, with first-quarter production dropping by 61% to 597 000 t, down from 1.52-million tonnes in the same period last year.

South32's South African manganese operations, on the other hand, saw a 12% increase in output during the same quarter, buoyed by strong mining performance. Maintenance for these operations is scheduled for the June 2025 half-year.

At Worsley Alumina, in Australia, saleable production declined by 7% to 850 000 t in the first quarter, attributed to planned calciner maintenance and limited bauxite supply owing to delayed mining approvals.

Despite this, South32 has maintained its 2025 production guidance at 3.75-million tonnes, with plans to convert excess hydrate stocks to calcined alumina throughout the year. Alumina sales decreased by 15% owing to lower product availability and shipment timing.

South32 expects the Western Australian Environment Minister to consider the Worsley mine development project for approval in December, with federal approvals expected to follow shortly thereafter.

The Western Australian Environmental Protection Authority recommended the approval for the Worsley bauxite mine in July, but imposed conditions that could pose significant challenges. South32 has lodged an appeal.

Last week, the Western Australian government announced it would defer regulation of greenhouse-gas emissions to the federal government’s safeguard mechanism. This change aims to resolve policy inconsistencies, says South32, and will likely be addressed during the appeals process for the project.

Meanwhile, CEO Graham Kerr said South32 maintained its yearly production guidance for all of its operations with a strong start to the year in aluminium and a 20% uplift in copper equivalent volumes from Sierra Gorda, in Chile.

Aluminium output rose 3% year-on-year to 298 000 t, with Hillside in South Africa producing 180 000 t in the three months under review.

During the quarter, South32 also completed the sale of Illawarra Metallurgical Coal, in Australia, which Kerr described as a "major milestone" that "unlocked significant value and streamlined the business toward commodities critical for a low-carbon future".

"The sale has also lowered our sustaining capital intensity and strengthened our financial position, enabling us to self fund our growth in base metals and deliver returns to shareholders via our on-market share buy-back," he said.

The sale of Illawarra helped South32 to lower its net debt from $723-million, to $39-million in the September 2024 quarter.