Passive Remediation of Acid Mine Drainage

Contamination of fresh water resources by acidic and metalliferous effluents emanating from mining activities has rendered the environment unsuitable to foster life. Mine effluents from coal and gold mining are mainly acidic and contains elevated levels of toxic chemical species. Due to their toxic nature, this water need to be contained and treated prior discharge to the nearby environments.This book reports on the state of art technologies that were developed for remediation of acid mine drainage using cryptocrystalline magnesite, bentonite clay and mechanochemically synthesized cryptocrystalline magnesite-bentonite clay composite. Laboratory studies proved that the fabricated composite can neutralise acidity in mine effluent and attenuate elevated levels of chemical species. The obtained results were substantiated by PHREEQC geochemical modelling and it was pointed out that chemical species were precipitating as hydroxides, ferric hydroxides, oxyhydrosulphates and carbonates.