Utilization of coal ash for preparation of seedbed in disturbed land in Indonesian open cut coal mine

The amount of coal ash disposed as industrial wastes is increasing with increasing coal demands all over the world. Although coal ash is generally disposed by landfill, the demand of effective utilization of them is increasing because of the limitation of the disposal site. Moreover, in Indonesia, most of soil is classified as acrisol which is acid and clay-rich soil. As the plant growth is inhibited under the acid and low permeability, the utilization of coal ash is expected in order to improve physical and chemical conditions of seedbed in the revegetation area. In this paper, the utilization of coal ash for preparation of seedbed in disturbed land in Indonesian open cut coal mine is discussed by means of several laboratory tests, column leaching test, and laboratory vegetation test by using Acacia mangium. Considering the obtained results, it was suggested that the coal ash can be utilized to improve the physical and chemical conditions of seedbed and the growth rate of Acacia mangium by incorporated into soil with proper mixture rate.