Natural oxidation of sulphide mineral wastes during their disposal and storage at the mining sites may
result in generation of acid rock drainage (ARD) that may contain high acidity and high concentrations of
dissolved metals and sulphates. Due to its chemical composition, ARD poses potential harm to the
environment and significant challenges to many mining industries requiring development and application of
effective ARD management plans to the mining sites during the operational and post-closure periods. If the
generation of ARD cannot be prevented or controlled, it must be collected and treated to eliminate acidity
and reduce the concentration of heavy metals and suspended solids before its release to the environment.
As a group of microorganisms may contribute to the generation of ARD, different types of
microorganisms may play a vital role in the development of microbiological prevention, control and
treatment technologies. The role of microorganisms in the generation of ARD and their role in the methods
used for prevention, control and treatment are discussed in this paper. Benefits, limitations and design
criteria for passive biological processes are presented using examples of passive and biological treatment
processes that have been developed recently and implemented to mine sites. © 2002 SDU. All rights
reserved.