The cost of building Hancock Prospecting's Roy Hill iron ore mine in the Pilbara has been disclosed as $7.2 billion, as the project has been given the green light to build a railway from mine to port.

The cost of building Hancock Prospecting's Roy Hill iron ore mine in the Pilbara has been disclosed as $7.2 billion, as the project has been given the green light to build a railway from mine to port.