Under the agreement, Itochu and Mitsui are investing about $800m and $700m for 8% and 7% stake respectively in Jimblebar iron ore mine.

The Jimblebar mine, which is located in Western Australia’s Pilbara region, is wholly owned by BHP.

ITOCHU and Mitsui already collectively own a 15% stake in BHP Billiton’s iron ore mine, rail and port infrastructure in Western Australia. The latest investment will align the Japanese companies’ interests across the Western Australia Iron Ore supply chain and drive simplicity and flexibility.

BHP Billiton Iron Ore president Jimmy Wilson said that the new Jimblebar mine will have initial production capacity of 35 million tons per annum (100 per cent basis) with future expansion potential.

"Once fully operational this will bring Western Australia Iron Ore’s supply chain capacity to 220 million tonnes per annum (100 per cent basis)," Wilson said.