Uranium

Uranium is one of the most powerful natural energy sources known to humanity. It is a naturally occurring metallic element that possesses an unstable atomic nucleus which, in becoming stable, releases energy in the form of radiation. Radiation can be harnessed to produce other forms of energy, such as heat. In nuclear power stations, this heat is used to produce steam, which drives conventional turbine generators to generate electricity.

Nuclear energy offers a clean, stable source of energy for heat, light and power. It does not generate carbon dioxide emissions, which reduces greenhouse gas emissions every year.

Uranium production
Ore body containing uranium is loosened from surrounding rock by blasting with explosives. After each blast, electric shovels load the ore-bearing rock into 180 tonne haul trucks, which deliver the ore to primary crushers. These crushers are gyratory, each capable of reducing a haul truck's load into pieces measuring approximately 16 centimetres in size within 10 minutes.

The ore passes through another three crushing stages, further reducing its size to the consistency of fine sand in the rod mills. Sulphuric acid is used as a leaching agent to dissolve uranium out of the rock. Manganese and iron oxide are added to oxidise the uranium to a soluble state in order to improve the extraction of uranium from the rock. Rotoscoops and thickeners separate the solution from the ground rock, with solid waste material being pumped into tailings dams for disposal.

The first stage in the recovery of uranium from the solution is the continuous ion exchange process. Here, the solution comes into contact with specially formulated resin beads where the uranium is absorbed into the resin and is preferentially extracted from the solution. An acid wash strips uranium from the beads. The uranium-rich solution is pumped into a solvent extraction plant where it is further concentrated and remaining impurities removed. Gaseous ammonia is then added to the uranium solution, causing a precipitate called yellow cake to form. Yellow cake is dried and roasted at temperatures in excess of 600°C to produce the final product of the process: uranium oxide in powder form. Uranium oxide powder is safely and securely packed into steel drums for delivery to Rio Tinto's customers.

Uranium production and the environment
Rio Tinto is committed to meeting the highest environmental standards. Both ERA and Rössing implement comprehensive and complex suites of environmental regulations at its mine sites in Australia and Namibia:

ERA has started a new water purification plant at Ranger to ensure that waste water from the uranium production process reaches drinking water standard before it is released from the site to the surrounding environment. At Jabiluka, ERA signed a landmark agreement on the long-term management of the lease area with the support of the area's traditional owners.

Rössing's commitment to sustainable development ensures that the positive developments from the period of mining is translated into long-lasting positive effects for the region, including community development programmes and improvements to dust management at the plant, water conservation and biodiversity.

More information about Rio Tinto's uranium operations at ERA and Rossing can be found at their respective websites:

For more information on our other products, see our corporate fact sheets.