Rio's move effectively cuts Rusal's access to production and management at the refiner under an Australian ban against exporting alumina and aluminum ores.
European utilities will have to be prepared to pay premiums to draw cargoes from South Africa, the Americas, Australia and Indonesia, writes Clyde Russell.
The assets, worth about $1.2 billion, include Mineracao Corumbaense, Mineracao Mato Grosso, International Iron Company and Transbarge Navegacion ventures.