Mining with microbes

Abstract

As early as 166 AD, biotechnology was applied to the extraction of metals from ores in the copper mines of Cyprus, and in 1928 in Kennecott, USA, ?dump leaching? ? the use of microorganisms to extract copper from low grade mine waste material ? was conducted on commercial scale. It was not until 1947 that Colmer and Hinkle 1 demonstrated the role that microorganisms play in the oxidation of mineral sulfides for the release of metals in solution. Currently, 20% of annual global copper production results largely through the bioleaching of chalcocite (Cu2S). Many other metals, such as gold, cobalt, nickel, uranium and zinc are also being produced through bioleaching technology. Today, biotechnology is used to improve the environmental outcomes in a range of mining operations such as the use of sulfate-reducing bioreactors for the treatment of acid mine drainage (AMD), and heterotrophic and chemolithotrophic biofilm reactors for the degradation of cyanide products from gold processing and for the destruction of organic wastes such as oxalate from Bayer liquors during alumina production.