Minerals are recovered through the leaching process. The minerals that are readily oxidized are iron and copper, but leaching also is used for gold and uranium. In the microbial leaching, the ore is dumped into a large pile and dilute sulfuric acid at pH 2 is percolated into the stack. The liquid that emerges is rich in minerals and is transported to a precipitation plant where it is purified. The liquid is then returned to the top of the pile, and the cycle is repeated.
The precipitation plant is where the Cu2+ from leaching is recovered. Cu2+ is improved by adding scrap metal iron to the precipitation pond. Temperatures in a leaching dump rise and this lead to shifts in an iron-oxidizing microbial community.