Mining activities and other geochemical processes often
result in the generation of acid mine drainage (AMD), a
phenomenon commonly associated with mining activities.
It is generated when pyrite (FeS ) and other sulphide
minerals in the aquifer and present and former mining
sites are exposed to air and water in the presence of
oxidizing bacteria, such as Thiobacillus ferrooxidans, and
oxidised to produce metal ions, sulphate and acidity
(Ogwuegbu and Muhanga, 2005).