Salt

Salt has been in use since ancient times. It was used to preserve Egyptian mummies, and sprinkled onto the stage in old Japanese theatres to ward off evil spirits.

Salt is essential for human life. A well-known food ingredient, salt is also critical for many industries. The majority of the salt Rio Tinto produces is used by the chemical industry, where it helps make materials like glass, paper, plastics, textiles and even soaps and detergents. Some of our salt is also used to process foods and de-ice roads.

Salt at Rio Tinto

Our Dampier Salt operations in Western Australia are the world’s largest exporter of solar salt – meaning salt that is produced from evaporating seawater, as opposed to being mined as a solid mineral. We export between 6 million tonnes of salt every year (Rio Tinto share), with most of it going to customers in Asia and the Middle East.

Dampier Salt is one of our oldest businesses and uses a unique and sustainable production process that relies almost entirely on the power of the sun and wind.

The shallow evaporation flats across Dampier Salt’s 3 operations have the potential to produce salt almost infinitely. The operations rely on natural processes of evaporation over an area greater than 21,000ha (equivalent to 168,000 Olympic sized swimming pools) to transform seawater into salt, predominately used for industrial purposes. The few million tonnes of seawater pumped over these shallow flats every day has created an important habitat that supports a variety of wading birds, including migratory shorebirds. The Dampier Salt operations are listed as Key Biodiversity Areas (KBA) by Birdlife Australia due to greater than 1% of the world population of Red-necked Stint, Curlew Sandpiper, Sharp-tailed Sandpiper and Red-capped Plover counted regularly each year. Port Hedland is also the most important known Australian site for Broad-billed Sandpiper and the endangered Asian Dowitcher.

As the sun and wind evaporate the water over months of exposure, we are left with a salty crust when salt crystals begin to form. Once dry, a specialised harvester collects the salt and transfers it to 320 tonne trucks for transfer to the washing plant. Here the salt is cleaned of impurities and stockpiled based on end-use specifications. From these stockpiles it is loaded onto ships at our on-site dock and transported to customers around the world.

Uses of our salt

Salt is a raw material and in industrial use helps make chlorine, caustic soda, and soda ash, all of which are used in processing and manufacturing of other products, including:

• PVC and polyutherane
• Glass
• Detergents and soaps
• Textiles
• Industrial chemicals
• Road de-icing