Acid Base Accounting of Mine Waste

Abstract

There has been a growing demand for environmental assessment of a mining site in the recent years. It has become very important that field and laboratory tests are to be performed to study the overburden and resulting mine tailings characteristics. Acid mine drainage is an environmental pollutant which damages water resources in mining regions throughout the world. Therefore in order to predict the post-mining water quality the amount of acid-producing rocks and acid consuming rocks are compared. On this basis a prediction of the water quality at the site, whether acidic, neutral or alkaline, is obtained. The determination of neutralization potential (NP) and acid-producing potential (APP) of mining wastes is an important part of waste characterization for AMD prediction. Interpretation of NP and APP values also requires consideration of the mineralogical composition of the mine waste. Different minerals can neutralize acid mine drainage at different rates and pH ranges. Many times the test conditions of widely used laboratory procedures to determine NP and APP result in their overestimation. Acid base Accounting is an analytical procedure which helps us to predict whether acid mine drainage would occur or not during and after mining operations. ABA is one of the preferred methods to predict post-mining water quality. NAG test is also an important tool to determine net acid generation potential of a mine waste