An Evaluation on Mixture Materials Using Overburden and Flyash as Cover Layer for Acid Mine Drainage Prevention and Underlying Materials of Seedbed in Indonesian Coal Mine

Abstract

Almost of the coal produced is from open-cut mines in Indonesia. Mining operation of open-cut mines causes a decreasing of a tropical rainforest and gives serious impacts on surrounding environment. Therefore, the environmental reconstruction by revegetation in the disturbed land is required. Mining operation of an open-cut mines requires removal of overburden and placement of them as waste rock dump. However, some of overburden contains sulphide contents which causes Acid Mine Drainage (AMD) and may be undesirable for plant growth because of high salinity, high soluble metal concentrations and high acidity. Furthermore, additional of flyash to waste rock dump for neutralizing AMD is discussed in current researches. As the important object of rehabilitation program is the creation of stable and self-sustaining land surface by vegetation, an assessment of overburden and flyash as planting base have to be discussed. In this study, several geochemical static and kinetic tests for overburden and flyash were carried out to prevent AMD generation and to discuss the impact to plant growth. It was revealed that the adverse effect to plant growth from overburden and flyash can be reduced by effective AMD prevention and preparing appropriate curing period of the ground until the of dissolution of metal ions are decreased.