Uranium is a chemical element with the atomic number of 92 and the chemical symbol of U. It was discovered in 1789 by Martin Heinrich Klaproth who named the element after the planet Uranus. Uranium is weakly radioactive, unstable and occurs naturally in low concentrations in rocks, soil and water. Uranium is commonly used in nuclear fission due to it being the only naturally occurring fissile isotope. It is used to create power in nuclear power plants, in nuclear weapons and as armor plating.
How is uranium mined?
There are three different ways to mine uranium depending on where it is located. Uranium is usually processed into a dry-powder form known as yellowcake once it has been extracted. Currently the three largest producers of uranium in the world are Kazakhstan, Canada, and Australia.
Open pit mining
When the uranium is close to the surface of the ground open pit mining is used to extract it. The top layers of dirt and rock, known as the overburden, are stripped away by drilling and blasting the area. This exposes the vein of ore that runs below these layers. The ore is extracted from the ground by blasting and is excavated using large machines such as loaders and dump trucks. The mine site is watered often to reduce the dust to lower the risk of exposure to radioactive materials.
Underground uranium mining
When the ore is not close enough to the surface of the earth to be mined using open pit mining, underground mine shafts and tunnels are dug to access the ore. This type of mining is not popular as it exposes workers to high levels of radon gas. Uranium is often mined alongside gold, silver and other hard metals in underground mines. The tunnels are dug and the walls are blasted to remove the ore from the surrounding rock. The ore is sent back to the top of the mine via machinery such as conveyor belts or mine carts.
In situ recovery
This process is also known as solution mining or in-situ leaching and is the use of chemicals to dissolve the uranium from the ore and then pumping this solution to the surface. Unlike the other forms of mining the ore is not taken from the ground and is left where it was found. This reduces the amount of surface damage caused by mining. For this type of mining to be successful the ore must be the specific type. A mixture of a complexing agent such as sulfuric acid and an oxidant such as hydrogen peroxide are pumped through the natural groundwater in the ore body. The solution with the now dissolved uranium in it is pumped back to the surface of the mined and collected.
Another method that is being experimented with is extraction from seawater. It is believed that seawater contains approximately 3.3 mg per cubic meter of uranium. A method is being tested by which uranium is collected using a uranium-specific nonwoven fabric as an absorbent. As the seawater passes through the fabric the uranium is extracted from the water.