Environmental regulators for the office of the Supervising Scientist admitted to an Australian Senate Estimates committee that water with uranium concentrations 5400 times the background level and a cocktail of other radionuclides are seeping from beneath the tailings dam at the Ranger Uranium Mine in Kakadu National Park, Australia. The Ranger Mine is operated by ERA, a 68.4% owned subsidiary of London-based Rio Tinto.
See http://scott-ludlam.greensmps.org.au/content/media-release/uranium-contamination-kakadu-mine-5400-times-background and http://www.abc.net.au/news/stories/2010/02/09/2814665.htm.