Investigating the origin and geochemical behaviour of toxic elements within the waste dumps using statistical analyses: a case study at waste dumps of Sarcheshmeh copper mine, SE of Iran

Abstract

Knowledge of the possible origin and behaviour of toxic elements in waste dump systems plays a crucial role in evaluating the potential risks for environment in mining sites. Sequential extraction experiments are often used to investigate the origin and behaviour of toxic elements. However, these experiments are not common in waste dumps due to need of the large number of samples for considering the heterogeneity. Therefore, this paper attempts to determine the origin and behaviour of Cd, Cu, Cr, Mo, Pb and Zn in waste dump using statistical analyses. For the aim of this study, sixty samples were collected from two waste dumps at the Sarcheshmeh Copper mine in Kerman province of Iran. The samples were characterised via ICP, XRD, ASTM-D2492 and paste pH experiment. Principle component analysis (PCA), hierarchical cluster analysis (HCA) and correlation analysis (CA) were used to identify the relationship and interdependency amongst the concentrations of toxic elements and the exact mineral contents. For detailed investigation, the samples were classified according to the paste pH value and then correlation analysis (CA) was performed. The results in comparison with previous experimental investigations revealed that pyrite and aluminosilicate minerals were the main sources of contamination. It was also found that hydroxysulphate minerals, manganese and iron oxyhydroxides, muscovite and chlorite were the principal minerals which control the concentrations of toxic elements in the waste dumps of the Sarcheshmeh porphyry copper mine.