Fly Ash Application for Reduction of Acid Mine Drainage (AMD) as Runoff and Leachate Released from Mine Waste Disposal Sites

Mine wastes such as acid mine drainage (AMD) can cause the detrimental effects on surrounding environment, thereby eventually threatening human health. Main objective of this study was to evaluate the neutralizing effect of fly ash (FA) as a stabilizing material AMD. Field plot was constructed in a coal waste depot which has caused aluminium-whitening adjacent to the stream. Different mixing ratios of FA were applied on a top of the soil, and then the physicochemical properties of runoff and soil were monitored. Constructed plots were as following: control (mine waste only (W)), mine waste + 20% (<TEX>$w\;w^{-1}$</TEX>)of FA (WC20M), mine waste + 40% (<TEX>$w\;w^{-1}$</TEX>)of FA (WC40M), and WC40M dressed with a fresh soil at the top (WC40MD). Result showed that initial pH of runoff in control was 5.09 while that in WC40M (7.81) was significantly increased. For a plot treated with WC40M, the concentration of Al in runoff was decreased to <TEX>$0.22mg\;L^{-1}$</TEX> compared to the W as the control (<TEX>$4.85mg\;L^{-1}$</TEX>). Moreover, the concentration of Fe was also decreased to less than half at the WC40M compared to the control. Application of FA can be useful for neutralizing AMD and possibly minimizing adverse effect of AMD in mining area.