Waste

For all our health, safety and environment (HSE) risk areas, we apply a robust management framework. This makes sure we manage our risks effectively. We continually review and improve our internal control procedures (standards, strategies, strategic risk reviews and the business unit conformance audit programme) to be sure they are fit for purpose. This is how Rio Tinto maintains its position as a leading manager of HSE risk.

We have mineral waste and non mineral waste standards and a hazardous materials and contamination control standard that our businesses follow. These standards support our Environment policy. They are implemented with clear guidance. Best practice is identified and shared and support provided as required.

Mineral waste

Mineral wastes include waste rock, tailings and slag:

• Waste rock is composed of soils or bedrock that must be removed to uncover or access ore during mining.
• Tailings consist of ground up rock mixed with process water that remains after the minerals of economic interest have been removed from the ore.
• Slag is generated by smelting operations and is the glassy material that remains after metals, such as copper, have been removed from the ore concentrate.

Mineral wastes are typically produced in very large volumes. Their handling and storage can directly impact the land. Mineral waste is usually permanently stored on site where it is used as in pit backfill or held in engineered repositories. Most mineral wastes are inert, but some are chemically reactive and must be appropriately handled to protect people, wildlife and water quality.

We manage the potential environmental impacts of mineral waste by:

• minimising the mass of material that must be stored;
• limiting the waste's disturbed footprint;
• ensuring repositories are physically and chemically safe; and 
• practising progressive rehabilitation, This means that lands impacted by mineral waste disposal can be returned to productive post mining uses.

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

Non mineral waste

Non mineral waste is primarily composed of the auxiliary materials that support our mining and mineral processing operations. This includes familiar materials such as used oil, tyres, old batteries and office waste, as well as more specialised waste streams such as spent pot liners from aluminium smelters. Non mineral waste is produced in much smaller volumes than mineral waste, and is most commonly managed through recycling, off site treatment and disposal, or placement in on site engineered landfills.

We limit the potential impacts of non mineral waste by trying to reduce the volume and hazard of the wastes that must be generated. We promote reuse and recycling where possible and ensure responsible storage, treatment and disposal for the remaining waste. All operations and projects are required to comply with our Non mineral waste management standard. This standard covers all aspects of waste management from initial generation through handling, storage and transport, to ultimate recycling, treatment or disposal.