The Worsley Alumina Refinery takes its name from the historic timber settlement of Worsley, near Collie in the south west corner of Western Australia. More than 1200 people are employed at the mine site and refinery. Worsley Alumina is a joint venture between BHP Billiton (86 per cent), Japan Alumina Associates (Australia) Pty Ltd (10 Percent) and Sojitz Alumina Pty Ltd (4 Percent).