Environmentally benign disposal of coal combustion products/by-products (CCPs) such as flyash and bottom ash has been a problem since the first coal-fired power plant went on-line. In recent years, ways have been developed to recycle CCPs into useful commercial products like bricks and roadbase. This article describes an innovative State of Maryland program that is putting CCPs to yet another use: stabilizing abandoned mines to permanently sequester acids and harmful metals.