Sibanye-Stillwater, the South African mining group, reported a mixed operating performance for the third quarter of 2026, as stronger precious metals prices lifted earnings despite declining production across several major operations, rising costs and a five-week strike at its US platinum group metals (PGM) operations.

The Johannesburg- and New York-listed miner disclosed that adjusted EBITDA increased 9% year-on-year to R10.77 billion ($662 million) for the period ended September 30, 2026, compared with R9.87 billion ($560 million) a year earlier.

The improvement was supported by higher commodity prices and stable performance from its South African PGM, gold, recycling and Century zinc operations.

However, industrial action in the United States disrupted mining and processing activities, forcing the company to lower its full-year production and cost guidance for its US PGM operations.

Production declines across major mining operations

Sibanye-Stillwater‘s South African PGM operations produced 439,802 ounces of 4E metals during the quarter, down 11% from 493,863 ounces in the corresponding period of 2025. The decline reflected lower underground and surface production, particularly at Kroondal, as well as the depletion of surface reserves and the closure of the Klipfontein opencast operations.

South African gold production also declined 12% to 155,449 ounces from 175,929 ounces, reflecting weaker underground output at Beatrix, Driefontein and Kloof. Flooding at Driefontein’s Khomanani 8 Shaft resulted in a six-week suspension of mining activities, while difficult ground conditions affected productivity at Beatrix.

In the United States, PGM production fell 19% to 59,417 ounces from 73,171 ounces, as the strike affected the Stillwater mine and Columbus processing complex. By contrast, payable zinc production at the Century retreatment operation increased 2% to 25,000 tonnes.

Rising costs weigh on mining operations

Production challenges and higher operating expenditure pushed costs higher across several divisions. South African PGM all-in sustaining costs (AISC) increased 5% in absolute terms, reflecting inflationary pressure on consumables, higher sustaining and development capital expenditure, and increased royalty payments.

South African gold unit AISC, excluding DRDGOLD, rose 23% year-on-year to R1.87 million per kilogram, largely because lower production increased the cost per unit. US PGM AISC climbed 39% to $1,617 per ounce, reflecting reduced output and higher capital expenditure associated with the group’s mechanisation programme. At Century, zinc AISC increased 25% to $2,520 per tonne, driven by higher fuel and reagent costs.

US strike forces revised production guidance

The five-week strike, which began on September 3 and ended after employees returned on October 9, significantly affected US operations. Although concentrate inventories helped limit the decline in sales volumes during the quarter, the company expects the full impact to become more apparent in the fourth quarter.

Sibanye-Stillwater has consequently reduced its 2026 US PGM production forecast to between 245,000 and 255,000 ounces, from its previous guidance of 280,000 to 300,000 ounces. Its AISC forecast has also increased to between $1,700 and $1,760 per ounce, including Section 45X production credits.

Sibanye-Stillwater’s Chief Executive Richard Stewart said the conclusion of the labour negotiations and introduction of team-based incentives represent an important milestone in the transition towards a more productive, mechanised operating model. The group is targeting approximately 410,000 ounces of steady-state production from its US operations and an AISC of about $1,000 per ounce by the end of 2028, as it works to restore production and improve operational efficiency.