Olympic Dam mine is a large poly-metallic underground mine in South Australia. It is the fourth largest copper deposit and the largest known single deposit of uranium in the world. It is mired in controversy. Conservationists want BHP to stop using evaporation ponds at Olympic Dam that kill hundreds of birds, including threatened species. Despite the fact that storage of the tailings, which include radioactive materials and acids, has been controversial since Olympic Dam’s previous owner, Western Mining Corporation, confirmed in 1994 that 5 billion cubic metres of the tailings fluids had leaked out of the storage facilities and into an aquifer underground, the company plans to expand the height of the tailings dam walls and increase the volume of radioactive tailings stored. Work is expected to be completed by 2023 despite strong opposition. The consequence of potential failure of Olympic Dam tailings dams is rated “extreme.”