Managing Water Quality in Mining Areas: Changing Paradigm of Sustainability

Abstract

AbstractWater is an important resource and a necessity for the mining and minerals processing industries. The mining and mineral-based industries extract water from groundwater, streams, rivers, and lakes, for mineral processing, dust suppression, and slurry transport. When the available water in mines is in excess, it can cause flooding in the underground mines; and when it is scarce, it can significantly influence the mining operations. Wastewater generated by the underground and open-cast mines and acid mine drainage produced from the oxidation of metal sulfides, contains higher levels of dissolved aluminium (Al), iron (Fe), and sulfate (SO4). The oxidative dissolution of sulfide minerals releases extremely acidic leachates consisting of toxic elements such as sulfur, arsenic, cadmium, copper, chromium, nickel, lead, uranium, and zinc, which can potentially affect the surrounding environment. The interactions of the elements associated with acid mine drainage is necessary to study for developing proper wastewater management strategy. Studies have shown that the mining activity influences the groundwater and also contaminates water bodies in proximity. In India, water discharge standards/limits containing 33 parameters were framed under the Environment (Protection) Rule, 1986 (under Schedule VI) by the Ministry of Environment, Forest and Climate Change (MOEFCC). Mining wastewater management from surface, underground, and acid mine drainage is therefore one of the most challenging factors in the mining sector. There were several techniques available to treat physiochemical properties of polluted water such as screening, skimming, sedimentation, neutralization, equalisation, oxidation pond, activated sludge process, trickling filters, chlorination, and reverse osmosis. The Total Dissolved Solids (TDS), Total Suspended Solid (TSS), Biological Oxygen Demand (BOD), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), are the most common parameters that are monitored and treated by the mining companies. In order to meet the present as well as future demands for creating the effective water management strategies, the mining companies need to be increasingly conscious of the risks and opportunities involved in the management of water resources. Although the modern water management systems have better modelling tools, these systems need improvement in their online monitoring tools for data collection, organization, and transfer. To secure quantity as well as quality of water throughout the life cycle of a mine, it is important to make optimum utilization of available resource and ensure its recycling. This chapter provides a critical review of the issues in the management of mine waters and their influence on the health and environment.KeywordsAcid mine drainageGround waterMetal toxicitySurface waterContaminantsRecycling processes