American aluminium producer Alcoa says a $3.3 billion acquisition of its Australian partner Alumina will better enable it to grow its footprint in local bauxite mining and alumina refining at a time when its Portland aluminium smelter in Victoria is losing money.

Alcoa has offered to exchange each share in Alumina Limited for 0.02854 of its New York-listed stock, under a proposal that has been endorsed by Alumina’s independent directors and its biggest shareholder, Allan Gray.