The Cardiff Borehole project is located in the Newcastle Coalfield of New South Wales about 20 kilometres south-west of Newcastle and 17 kilometres by rail to the port of Newcastle. Cardiff Borehole is part of the Macquarie Coal Joint Venture which is 80% owned by Oceanic Coal Australia Ltd (OCAL), a wholly owned subsidiary of Xstrata. The other Joint Venture participants are Marubeni Coal Pty Ltd (17%) and JFE Mineral (Australia) Pty Ltd (3%).

The Cardiff Borehole has indicated resources of 12.4 million tonnes and inferred resources of 22 million tonnes of coal.