Abstract

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur mineral pyrite(FeS₂). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this paper the generation characteristics and the prediction of ARD of various cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Fourteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

Keywords pyrite, oxidation, acidification, contamination, slope stability