Tailings are a slurry like material which consist of finely ground rock, process water and residual reagents. This is the leftover material after the copper concentrate is extracted from ore. Some of the tailings are mixed with a cement binder and used to backfill mined areas underground as a geotechnical ground support method. Tailings material that cannot be reclaimed in this manner is stored in a tailings storage facility (TSF).
The TSF has a downstream design and is located within an Integrated Waste Landform. This is considered to be one of the most stable design options available. Tailings are deposited into a circular impoundment with a composite liner comprising high density polyethylene and compacted clay.
Our TSF is governed in accordance with our Environmental Management System (EMS) standards and operated in line with regulatory requirements. Annual independent audits of the TSF are conducted by specialist engineers and are undertaken in accordance with the DMIRS and Australian National Committee on Large Dams standards.
Tailings facility disclosure
In April 2019, the Church of England Pensions Board and the Council on Ethics Swedish National Pension Funds wrote to approximately 700 mining companies requesting information on their tailings facilities and approach to tailings management. Sandfire complied with this request and our full disclosure can be read here.