Roughly 200 union members at South32's Worsley Alumina refinery in Western Australia started a 48-hour stoppage on November 10, seeking firmer protection of their pay and working conditions ahead of Alcoa's agreed purchase of the company's aluminium assets.
The stoppage involves members of the Electrical Trades Union (ETU) and the Australian Manufacturing Workers' Union (AMWU) and overlaps with a scheduled shutdown of the refinery's main processing plant. AMWU state secretary Steve McCartney put union membership at the Worsley operation at about 200 and said workers want existing earnings secured before ownership changes hands.
Incentive payments become the sticking point
Short-term incentive payments are the central dispute. McCartney said Worsley employees have received an average bonus of 10 per cent over the past five years and want that payment written into their enterprise agreement. The union argues South32 has cited incentive payments when describing overall remuneration but has not offered a binding guarantee to preserve them. According to McCartney, the claim is not for higher pay but for continuation of benefits already received.
Working hours divide the two workforces
ETU WA secretary Adam Woodage pointed to differences in hours between South32 and Alcoa employees in comparable roles: Alcoa's shift and day workers operate a 36-hour week, against 42 hours for shift workers at Worsley, while South32 day workers complete 40 hours across four 10-hour days. Woodage said those gaps would attract more scrutiny as the two companies combine their aluminium operations, and that employees want an agreement recognising their skills and contribution.
South32 said it was negotiating constructively with employees and their representatives, that Worsley staff receive benefits beyond base wages, and that its current short-term incentive policy would continue after completion. The company said contingency plans would keep the refinery running and it did not expect the stoppage to affect production.
What Alcoa is buying
The dispute sits inside a transaction announced in July 2026 with an implied enterprise value of up to USD 5.6 billion. It covers:
- South32's 86 per cent interest in Worsley Alumina in Western Australia;
- full ownership of the Hillside Aluminium smelter in South Africa;
- a 33 per cent interest in the Mineração Rio do Norte bauxite mine in Brazil;
- a 36 per cent interest in the Brazil Alumina refinery and a 40 per cent interest in the Brazil Aluminium smelter.
Consideration comprises USD 3.1 billion in cash, about USD 1 billion in newly issued Alcoa shares, roughly USD 750 million of net debt and lease liabilities assumed by Alcoa, and up to USD 750 million in contingent cash payments tied to agreed alumina and aluminium price targets through 2030. Alcoa will also take on rehabilitation provisions estimated at about USD 1.2 billion, which sit outside the enterprise value. South32 intends to pass roughly half of the Alcoa shares it receives, worth about USD 500 million at the time of announcement, to eligible shareholders through a fully franked special dividend after completion. Mozal Aluminium in Mozambique is excluded and remains with South32 on care and maintenance.
South32 shareholders approved the deal on October 15, 2026, with completion targeted for June 29, 2027, subject to regulatory and other closing conditions.
Worsley's role in the enlarged group
Worsley has capacity of about 4.4 million tonnes of alumina a year. Wood Mackenzie estimates the acquisition would lift Alcoa's attributable bauxite production by 53.6 per cent to nearly 53 million tonnes annually and attributable alumina output by 51.6 per cent, while adding around 26 per cent to smelting capacity. Alcoa expects about USD 900 million in net present value from operational synergies, including tighter integration between Worsley and its existing Western Australian operations. The enlarged portfolio is expected to produce roughly 14.8 million tonnes of alumina and 3.2 million tonnes of aluminium a year.
Against that backdrop, retaining experienced staff and keeping Worsley running smoothly will matter as Alcoa integrates the assets, making the enterprise agreement outcome a factor in how one of the deal's key sites is operated.