Water balance

Water is used in all aspects of a mineral operation including exploration, mining, processing, smelting and refining and sometimes for supply to local towns.

We are committed to minimising the amount of water we remove from the environment, and recycling or reusing is an effective way of doing this.

How we manage our water

Many operations are located in arid areas where water supply is limited and the local water supply may often be poor quality. Sometimes significant infrastructure is required for supplying water to the site. Operations can also be located in areas where there is sufficient or sometimes too much water.

So different approaches to managing water scarcity and water excess are required.

Water being returned to the environment after it has come into contact with mining or processing activities has a potential environmental and community impact because its quality may have been altered.

Any water that we discharge from our operations is done so according to water quality compliance limits. Many operations do not discharge water at all as they are able to recycle or lose water via evaporation. Those that do discharge their water often treat it so as to comply with our strict discharge limits.

Our results

In 2007 we used 997 billion litres of water compared to 1,008 billion litres in 2006. This water was used primarily for processing, cooling and dust suppression. A quarter of this water was recycled in our processes, the most common way being  to capture water that would normally be lost through the processing circuit via thickeners and tailings dams.

In 2006, several cyclonic events stopped production for a short time due to excess water at our Pilbara Iron operations in Western Australia. However, in 2007, fewer cyclonic events allowed a return to normal production in the region, in some cases necessitating additional water use for dust suppression.  This demonstrates how  the weather can impact the Group's performance from year to year.

Alcan's 2007 freshwater input was 190 billion litres, an eight per cent decrease from the 200 billion litre input in 2006. This was the result of improved water management at Alcan's Quebec hydroelectric generating facilities after installing control valves to automatically restrict water use during maintenance and shut down.