Rio Tinto's approach to the management of mineral wastes and on-site disposal includes:

• Selecting strategies based on detailed characterisation of the potential impacts associated with disposal of mineral waste and its intended disposal or storage location;
• Ensuring that design and construction of waste disposal facilities and sites are compatible with the waste behaviour and are engineered to best available technology for stability and safety;
• Having certified engineers conduct independent and external audits of waste disposal facilities, such as tailings dams, every two years to ensure that structures remain stable and safe throughout the life of the operations and after closure; and
• Managing Acid rock drainage (ARD) that is caused by the exposure and weathering of sulphide rock, chiefly the oxidation of pyrite (iron disulfide) in rocks and ores. The liquid drainage can contain acidity, sulphate, metals and dissolved salts, and can contaminate surface and ground waters. How we manage ARD