Around 200 union members at South32’s Worsley Alumina refinery in Western Australia began a 48-hour stoppage on November 10, seeking stronger guarantees on pay and working conditions before Alcoa completes its planned acquisition of South32’s aluminium assets. The action involves the Electrical Trades Union and the Australian Manufacturing Workers’ Union and coincides with a scheduled shutdown at the refinery’s main processing plant. The dispute is focused less on the ownership change itself than on whether existing earnings and employment terms will survive it.
Incentive pay and hours at the centre
The future of short-term incentive payments is the most sensitive issue. AMWU state secretary Steve McCartney said Worsley workers had received an average bonus of 10 per cent over the past five years and want that payment secured through their enterprise agreement. The union argues that South32 has referred to incentive payments when discussing overall remuneration but has not offered a binding guarantee. McCartney said the request is not for higher payments but for continuation of benefits workers have consistently received.
Working hours have added a second point of contention. ETU WA secretary Adam Woodage said Alcoa’s shift and day workers have a 36-hour working week, compared with 42 hours for shift workers at Worsley. South32’s day workers complete 40 hours across four 10-hour days. Woodage argued that these differences will come under greater scrutiny as the companies move towards combining their aluminium operations, and that employees want an agreement recognising their skills, contributions and role in the business.
The transaction behind the talks
Alcoa’s proposed acquisition has an implied enterprise value of up to USD 5.6 billion. Announced in July 2026, 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 Brazil’s Mineração Rio do Norte bauxite mine, a 36 per cent interest in the Brazil Alumina refinery and a 40 per cent interest in the Brazil Aluminium smelter.
The consideration comprises USD 3.1 billion in cash, approximately USD 1 billion in newly issued Alcoa shares, around USD 750 million in net debt and lease liabilities assumed by Alcoa, and up to USD 750 million in contingent cash payments linked to agreed alumina and aluminium price targets through 2030. Alcoa will also assume rehabilitation provisions estimated at about USD 1.2 billion, separate from the implied enterprise value. South32 intends to distribute roughly half of the Alcoa shares it receives, worth around USD 500 million at the time of the announcement, to eligible shareholders through a fully franked special dividend after completion. The deal excludes Mozal Aluminium in Mozambique, which remains with South32 and on care and maintenance.
The transaction is targeted for completion by June 29, 2027, subject to regulatory and other closing conditions. South32 shareholders approved it on October 15, 2026. Until those conditions are satisfied, the ownership change remains a planned event, and the labour dispute is unfolding against that timetable rather than after it.
Why Worsley matters to the combined portfolio
Worsley has annual alumina production capacity of approximately 4.4 million tonnes and is a significant part of Alcoa’s planned expansion across bauxite, alumina and aluminium. Wood Mackenzie estimates that the acquisition will increase Alcoa’s attributable bauxite production by 53.6 per cent to nearly 53 million tonnes annually, while attributable alumina production is expected to rise by 51.6 per cent. The consultancy also estimates that aluminium smelting capacity will increase by around 26 per cent.
Alcoa expects the acquisition to generate approximately USD 900 million in net present value through operational synergies, including improved integration between Worsley and its existing Western Australian operations. Once completed, the expanded portfolio is expected to produce around 14.8 million tonnes of alumina and 3.2 million tonnes of aluminium annually. Those figures explain why stable operations and experienced employees at Worsley carry weight in the integration case.
Company assurances and the limits of the dispute
South32 said it is engaging constructively with employees and their representatives during enterprise agreement negotiations. It maintains that Worsley employees receive benefits beyond base wages and that its existing short-term incentive policy will continue after the transaction is completed. The company also said it has plans to maintain operations during the industrial action and does not expect the stoppage to affect production.
Those are company positions, and the actual production effect of the 48-hour stoppage has not been established in the information provided. What is clear is that the bargaining agenda extends beyond a short walkout. The enterprise agreement under negotiation would govern pay and conditions after the ownership change, and the outcome could shape employment conditions at one of the key facilities in the proposed acquisition. For Alcoa, the value case rests on integrating Worsley with its existing Western Australian operations and on delivering the expected synergies; for the workforce, the test is whether existing incentive pay and hours are protected through that transition.
The stoppage is time-limited, but the issues behind it are tied to a transaction running until mid-2027. How South32 and Alcoa reconcile incentive payments, working hours and comparable terms will therefore matter for the Worsley operation and for the integration planning that underpins the deal.