Squire Sanders is advising Japanese trading houses Itochu Corp. and Mitsui & Co. on their $1.5 billion investment in a Western Australia iron ore mine owned by BHP Billiton Ltd.

The two companies are buying in through the purchase of shares in, and the offering of loans to, the BHP subsidiary that controls the so-called Jimblebar mine, located in the Pilbara region. Itochu will inject $800 million for an 8 percent stake in the mine, while Mitsui will invest $700 million for a 7 percent stake.

The deal, subject to regulatory review, is expected to close in September.