How to Extract Precious Metals From Sulfides | Sciencing
Employ bioleaching for base metals, such as zinc, copper and nickel, or mineral bioxoidation to enhance extraction of gold and silver. Both methods rely on bacterium, such as hiobacillus ferrooxidans, to recover precious metals. For example, stack ore in piles 200 feet deep. Apply waterdiluted sulfuric acid to enable bacterium to grow.