Formosa Plastics Group will invest $1.15 billion in the Iron Bridge project by Fortescue Metals Group.

The project is a joint venture between Australian iron ore producer Fortescue, with 88 percent of the shares, and a subsidiary of Shanghai Baosteel Group Corp with 12 percent of the shares.

Under the agreement, Formosa, through subsidiary Formosa Steel, will acquire a 31-percent unincorporated joint venture interest in FMG Iron Bridge Joint Venture and fund the first $527 million of capital expenditure on the project development.

FMG Iron Bridge joint venture owns the North Star and Glacier Valley iron ore deposits in Western Australia, a combined iron ore resource of 5.2 billion tons.

Formosa is Taiwan's largest private company.

The transaction is subject to Australian Foreign Investment Review Board and Taiwan investment commission approval, expected in September.