For each tonne of ore at the Ranger mine, only three kilos of yellowcake are recovered. Huge quantities of waste rock and low grade ore that are not milled, and millions of tonnes of tailings, are produced during the milling process. For every 3600 tonnes of uranium oxide, Ranger produces almost a million tonnes of tailings.
Tailings are pumped into a dam after being treated with lime to reduce the solubility of the heavy metals present. Regulated releases of about 2 million cubic metres of contaminated water from Ranger each wet season carry radioactive radium and toxic pollutants including selenium, copper, lead, cadmium and arsenic down nearby Magela Creek and into the flood plain, contaminating the precious Kakadu ecosystem.
(Ranger Uranium mine, Jabiru, Kakadu National Park, Arnhem Land, July, 1982. Tailings dam with Mount Brockman in background.)
After each successive wet season, radioactive wastes have become increasingly concentrated in plants, water and animals. A new mine at Jabiluka would also threaten Magela Creek. The tailings dam of the now-closed Rum Jungle mine, near Darwin, was breached by monsoon rains, and pollution now extends over 100 square kilometres, including the Finnis River.
At Mary Kathleen in the NT, where operations ceased in 1982, 1 million litres of radioactive liquid were deliberately released in February 1984 from the mine's evaporation ponds during an unexpectedly intense wet season. The Fox Report in the 1970s recommended against opening the Koongarra site, located inside a World Heritage Area, in order to protect the South Alligator River.
Uranium mining and milling release large quantities of radioactive radon gas into the atmosphere, as well as ammonia, nitrous oxide, sulphur dioxide and sulphuric acid mist, which kill plants and corrode rock faces. Mt Brockman near the Ranger mine has already suffered corrosion only a few years into the 30-year life of the mine.
(Ranger Uranium mine, Jabiru, Kakadu National Park, Arnhem Land, July, 1982. Tailings dump with Mount Brockman in background.)
Between 1956 and 1972, mining at Moline created 246,000 tonnes of tailings. Within 10 years of the closure of the mill, the tailings dams collapsed, releasing 63,000 tonnes of tailings. When the Office of the Supervising Scientist — established by the federal government to monitor the environmental impact of uranium mining in the NT — surveyed the site, it found significantly higher than normal levels of radioactivity in the flood plains of the creek below the mine and high concentrations of radionuclides in the sediments of the flood plain, as well as high rates of erosion from the tailings dam.