Rio Tinto–Chalco CBA acquisition: value chain and power lens for mine planners
Reviewed by Tom Sullivan

First reported on International Mining – News
30 Second Briefing
Rio Tinto and Aluminum Corporation of China Limited (Chalco) have agreed a joint venture, owned 33% by Rio Tinto and 67% by Chalco, to acquire Votorantim’s 68.596% controlling stake in Companhia Brasileira de Alumínio (CBA), a vertically integrated low‑carbon aluminium producer in Brazil. CBA’s portfolio spans bauxite mining, alumina refining and aluminium smelting/rolling, giving the JV immediate access to upstream ore and downstream semi‑fabricated products in a single platform. The deal signals stronger Chinese–Anglo participation in Brazil’s aluminium value chain, with implications for bauxite offtake, power‑intensive smelting capacity and low‑carbon product supply.
Technical Brief
- Joint venture structure fixes Rio Tinto at 33% equity and Chalco at 67% in the acquisition vehicle.
- Transaction targets Votorantim’s precise 68.596% controlling block in CBA, not full equity ownership.
- Deal scope covers CBA’s integrated chain: bauxite mines, alumina refinery, aluminium smelters and rolling facilities in Brazil.
Our Take
Among the 17 aluminium‑tagged pieces in our database, most activity has centred on bauxite and smelting in Australia, the Gulf and China, so a Brazil-focused M&A move by Rio Tinto and Chalco signals a deliberate push to diversify upstream and midstream exposure into Latin America.
The 33/67 ownership split between Rio Tinto and Chalco in the JV suggests Chalco will be the dominant strategic voice, which could shape CBA’s future capex priorities towards supplying Chinese and Asian markets rather than purely Brazilian or Atlantic trade flows.
With Votorantim holding 68.596% of CBA, any transaction structure will likely hinge on a single controlling shareholder decision rather than a fragmented register, which tends to shorten negotiation timelines but can concentrate political and community engagement risk around that one counterparty.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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