Only about three kilograms of uranium oxide are recovered from each tonne of ore. The left-overs, looking like liquid mud and called tailings, are pumped into a tailings dam. After mining ceases tailings dams become hills of fine sand which retain 80 per cent of the radioactivity in the ore body. Once mined they get into waterways and the atmosphere. Tailings are so finely ground that the radon escapes 10,000 times faster than from the ore body.
Tailings dams have a poor track record.
Waterways have been polluted by radium after a sudden collapse or constant erosion. Radon gas and radioactive dust are carried downwind. Since radioactive decay will persist for over 100,000 years the hazard will be virtually without end. Most of the world's uranium has been mined in the poor African countries of Namibia and Niger and on the remnants of land left to the indigenous people of North America. The mining sites have become radioactive wastelands bringing devastating health problems to indigenous peoples.