STUDY OF THE UTILIZATION OF FLY ASH TO PREVENT THE FORMATION OF ACID MINE DRAINAGE WITH MIXING AND COVER LAYERING METHOD

• Main Author: Saut Tahi - Nim: 12112032 , Benhard
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26067
• Institution: Institut Teknologi Bandung

<p align="justify">Mining activity is characterized by the activity of the excavation and dumping. Excavation and dumping activities will lead to exposure of sulphide minerals from rock to allow contact with air and rainwater, then form Acid Mine Drainage (AMD). The formation of the AMD that has happened will be difficult to discontinue as it is a continuous process until one of its reactants runs out. <br /> <br /> <br /> AMD formation can be prevented by using blending and cover layering method by using Non-Acid Forming (NAF) material to Potential Acid Forming (PAF). Blending method is done by mixing the PAF and NAF material to allow the acid formation and neutralizing reaction work simultaneously. Cover layering method is done by covering the PAF material with NAF material to prevent the reaction from sulphide minerals with air and/or water. Due to the least amount of NAF material in the field, fly ash is used as blending and cover layering material. Some tests were conducted to determine the characteristics of overburden and fly ash: physical test, element tests (using both Sequential Extraction method by Induced Coupled Plasma – Mass Spectometry and X-Ray Fluorescence), mineralogical test (X-Ray Diffraction), static geochemical test (ABA and NAG) and kinetic test (Free Draining Column Leach Test). <br /> <br /> Physical test confirmed the grain size of the overburden is sandy-silt and the fly ash is silt and clays. Based on the static test result and confirmed with kinetic test, it was found that the geochemical characteristics of the overburden is PAF and fly ash is NAF. Oxidation reactions and oxygen diffusion are still possible because the fly ash cracked. The mixing method is more effective in preventing the formation of AAT because pH values tend to be more stable than in coating methods. Amount of the fly ash will affect the average pH value. The bigger amount of the fly ash, the greater average value of pH. <p align="justify">