Potential role of acid mine drainage management towards achieving sustainable development in the Johannesburg region, South Africa

Abstract

Acid mine drainage has always been considered to be toxic to the environment. This paper highlights its potential role from a water resource perspective in alleviating water supply issues in the Witwatersrand gold mining region of South Africa. Relevant local and international literature on acid mine drainage (AMD) occurrence and treatment technologies were reviewed and supplemented with additional water quality data from AMD and geochemical data from tailings dams. This study revealed that the tailings dams contain high concentrations of toxic metals (Co, Pb, Cu, U, As, Fe) and oxides such as SiO2, Al2O3, Fe2O3 and FeO. AMD is characterized by acidic pH (1.89–3.50), high ORP (+485 mV to +650 mV), high EC (7475 μS/cm to 9750 μS/cm) and brackish TDS (6000 mg/L to 8890 mg/L). The discharge volume of acid mine drainage in the area is approximately 202 million L/day, which can be available to supply water for the community after treatment. This resource can also be fully utilized for extracting minerals, chemicals as well as clean water that are beneficial to support the sustainable development of the region. This may be achieved through the application of reverse osmosis that can produce safe drinking water and associated byproducts (metals, gypsum, iron compounds, acid), as well as neutralization and cation exchange methods to generate water for agricultural uses. The extraction of the minerals also has economic benefits and can contribute to job creation that limits the displacement of the local people in the mining region.