Diversified miner Rio Tinto has agreed to jointly acquire Votorantim’s controlling stake in Companhia Brasileira de Alumínio (CBA) alongside Aluminum Corporation of China (Chalco), strengthening its exposure to low-carbon aluminium production in Brazil.

Rio Tinto and Chalco have entered into a definitive agreement with Votorantim to acquire its 68.596% shareholding in CBA through a jointly owned vehicle, which will be held 33% by Rio Tinto and 67% by Chalco.

Under the terms of the transaction, announced on Friday, the joint venture (JV) will acquire Votorantim’s stake at an all-cash consideration of R$10.50 a share, representing a premium of about 21.2% to CBA’s 20-day volume-weighted average share price prior to the signing of the agreement.

The transaction values Votorantim’s shareholding in CBA at about $902.6-million, with Rio Tinto’s pro-rata contribution amounting to about $297.8-million, subject to closing adjustments and regulatory approvals.

Following completion, the JV will be required under Brazilian law to launch a mandatory tender offer for the remaining shares in CBA not held by Votorantim. The partners have also indicated that they may pursue a concurrent delisting tender offer, subject to further review after closing.

CBA operates a vertically integrated, low-carbon aluminium business in Brazil, underpinned by a 1.6 GW renewable-energy portfolio that includes 21 hydropower plants and wind power assets. The company’s operations are powered entirely by renewable electricity, enabling the production of low-carbon aluminium products for the domestic market.

Its asset base includes three producing bauxite mines with annual output of about two-million tonnes, as well as an integrated aluminium complex in São Paulo. The complex comprises a 0.8-million-tonne-a-year alumina refinery, a 0.4-million-tonne-a-year aluminium smelter, secondary recycling capacity of 0.3-million tonnes, and downstream processing facilities.

Rio Tinto Aluminium and Lithium CEO Jérôme Pécresse said the transaction aligned with the company’s long-term strategy by extending its low-carbon, renewable-powered aluminium footprint in rapidly growing markets. It also provides the opportunity to grow its bauxite and alumina supply chain in the Atlantic region.

The company added that the deal complemented its broader aluminium and lithium strategy, which focuses on supplying materials critical to the global energy transition.

The transaction remains subject to regulatory approvals and customary closing conditions.