(Sharecast News) - Rio Tinto said on Tuesday that it has agreed to buy Mitsubishi Corporation's 11.65% interest in Boyne Smelters (BSL) for an undisclosed sum.

BSL owns and operates the Boyne Island aluminium smelter in Gladstone, Australia.

Once this deal and the recent agreement to acquire Sumitomo Chemical Company's 2.46% interest in BSL complete, Rio's interest in BSL will rise to 73.5%.

The acquisition is subject to various conditions, including approval from Australia's Foreign Investment Review Board, and is expected to be finalised in the second half of this year.

"Rio Tinto looks forward to continuing to work with its remaining BSL joint venture partners and other stakeholders on securing a competitive low-carbon future for its Gladstone operations," the company said.