Effects of acid mine drainage on hydrochemical properties of groundwater and possible remediation

Abstract

Acid Mine Drainage (AMD) is a severe environmental problem in the area of metal and mining industries throughout the world. AMD becomes a pollutant for the surface and groundwater due to its highly acidic nature and high toxicity. From mineral exploration to the closing stage, mining methods, both opencast as well as underground, have serious environmental impacts with large-scale consequences. Sulphide minerals, mainly pyrite, present in coals when exposed to air and water and get oxidized and hydrolyzed to form sulphuric acid, which further dissolves heavy metals. Formation of AMD is a natural process but it is accelerated by large-scale indiscriminate, unscientific mining and construction activities. AMD is characterized by low pH, high acidity, and elevated concentration of sulphate, TDS (total dissolved solids), and heavy metals. Globally, groundwater quality deterioration is influenced by mine drainage. Leachates of AMD originating from overburdened mine waste have the potential to penetrate through the ground surface to the subsurface and contaminate groundwater. During the rainy season, leaching of heavy metals (Cu, Pb, Hg, etc.) from mine spoils happens more easily, thereby polluting groundwater. AMD treatment is mostly costlier than its control and it will take some years, even after mining activity has stopped. Initial identification of the problem has the potential to limit the factors accountable for AMD generation. This chapter conceives the fundamental science of AMD generation and its impact on groundwater quality, and also suggests the measures for its treatment and management. © 2021 John Wiley & Sons Ltd. All rights reserved.