Waste

Overview

When we extract minerals from rock, we create mineral and non mineral waste.

Mineral waste includes mined rock, tailings and slag, which are produced at very large volumes, have only limited value and can pose environmental hazards if poorly managed.

Non mineral waste includes such materials as coal ash from power plants, specialised aluminium smelter wastes, construction and office debris and mining-related wastes such as used oil, tyres and spent chemicals. 

How we manage our waste

Through improvements in mine planning (see Improving performance together) we are improving the efficiency with which we extract ore and manage our waste areas. We expect these measures to increase our productivity, reduce our fuel costs and lower our greenhouse gas emissions as our mines develop.

In order to reduce our impact on the environment with two different kinds of waste, we use a mixture of strategies:

Mineral waste

Mineral waste is what is left from the mined resource after the product has been shipped. This includes waste rock, tailings and slag. Acid rock drainage (ARD) is a common environmental problem associated with chemically reactive mineral wastes.

Careful management of mineral waste is critical to reduce costs while maximising the recovery of ore. Due to the large volumes of material involved, any improvements in the management of this waste can have significant savings, from savings in reduced energy consumption through to minimising future closure costs.

We generally manage mineral waste through responsible onsite disposal.  Where possible, mineral waste is used in pit or underground backfill, or is recyled and reused on site for other beneficial purposes.

Non mineral waste

Non mineral waste is primarily auxiliary materials that support our mining and mineral processing such as tyres, oils, batteries, refractory lining and domestic rubbish.  This type of waste is produced in much smaller volumes to mineral waste, and we reduce or eliminate it by recycling or reusing it wherever possible.