Joint venture partners in the Worsley Alumina project BHPBilliton, Japan Alumina Associates and Sojitz Alumina Pty Ltd have begun a full feasibility study to increase production at the Worsley refinery to 4.3 million tonnes a year.

The expansion is based on a $900 million construction project to upgrade the capacity of mining and refinery facilities at Boddington and Worsley. This expansion will be achieved by expanding mining operations within Worsley’s lease area, increasing the capacity of the conveyor that carries crushed bauxite from Boddington to the refinery and modifications and upgrades at the refinery.

The site is located approximately 20 kilometers northwest of Collie and approximately 180 kilometers south of Perth, Western Australia. The project is expected to commence in the third quarter of 2006 and will take approximately 24 months to complete.

The joint venture partners have contracted Bechtel Australia Pty Ltd to deliver Engineering Procurement and Construction Management services covering the Feasibility, Transition and Execution phases of the expansion.