Shark Bay Salt Pty Ltd is a wholly owned subsidiary of Mitsui & Co. Ltd, which is one of the world’s most diversified trading, investment and services enterprises. It owns and operates two saltfields in Western Australia — Shark Bay Resources and Onslow Salt.

Salt piles at the Onslow site.
Harvester loading truck with salt.The edge of the salt pond.

The Onslow operation — Onslow Salt

In 2006, Mitsui acquired Onslow Salt. The saltfield was built in the late 1990s and began shipment of salt in 2001.

Weather conditions in the area are favourable to solar marine salt operations, where annual evaporation is very high. This high evaporation ensures an efficient production capacity of solar marine salt.

The saltfield was built by enclosing a vast natural flat area facing the Indian Ocean with sea wall levees. This topographical feature allows the saltfield to manage the brine flow efficiently.

The saltfield encompasses an area of 220 square kilometres, of which 87 square kilometres are occupied by operational ponds. The saltfield’s operational ponds are closely interconnected. They consist of six evaporation ponds of 77 square kilometres and 15 crystalliser ponds of 10 square kilometres. Sea water is pumped into the first evaporation pond, and brine flows through most of the evaporation ponds by gravity.

Fully saturated brine is stored in the last evaporation pond before being fed into the crystalliser ponds. Large crystalliser ponds allow the Onslow Salt saltfield to utilise the area efficiently and operate a productive harvesting operation.

Onslow Salt has a salt-washing plant, a stockpile area and also its own port. Most employees and their families live in Company houses in the town of Onslow.