Treatment for Acid Mine Drainage Utilizing Dimension Stone Waste

When large quantities of rocks containing sulphide minerals are excavated from mines, they react with water and oxygen to create sulphuric acid. When this water reaches a certain level of acidity it also starts leaching traces of metals, this wastewater is termed as Acid Mine Drainage (AMD), affects the surface and subsurface hydrology and extends its impact to the surrounding land. Although, several AMD treatment techniques and methods exist, lime treatment is the most common approach which proves to be highly expensive. In this study dimension stone (Kotastone) waste, generated by the stone quarrying/cutting industries was used for the detoxification of AMD. The selection criteria of treatment agent was its free of cost availability. pH increased from 2.97 to 6.21, net acidity dropped from 1196.6 to 150 mg L-1 of CaCO3. Concentrations of metals like Fe2+, Cu2+, Zn2+, Ni2+, Co2+ and Mn2+ also reduced remarkably from 19.69 to 99.24%. The experiments were carried out in 500 mL cylinders with different waste doses ranging from 0.5 to 10 g. The cost comparison with hydrated lime and quick lime was also in favour of Kotastone waste for the AMD treatment Now, major efforts are required by the mining industry and the research laboratories to convert this prototype product into commercial ventures so that this waste can become a utility material instead of nuisance.