The speciation of cobalt and nickel at mine waste dump using improved correlation analysis: a case study of Sarcheshmeh copper mine

Investigating the speciation of potentially toxic elements in mining waste dump systems provides valuable knowledge about the potential for transfer in the environment and the risks posed to mining sites. Sequential extraction analyses are common experiments, which are often used to determine the speciation of potentially toxic elements. However, there would be some drawbacks for using this experiment including labour-intensive procedure, interferences of fractions, impractical for testing large numbers of samples from a heterogeneous environment and the inability to determine the individual minerals relevant to the corresponding fraction. The present paper is an attempt to determine the speciation of cobalt and nickel as potentially toxic elements in the waste dumps of Sarcheshmeh using improved correlation analysis. This method employed the cobalt and nickel contents together with the exact mineral contents which were classified according to the paste pH experiments for improving the correlation matrix. To achieve the aim of study, sixty samples were collected from two waste dumps at the Sarcheshmeh Copper mine in Kerman province of Iran. The result of proposed method showed that cobalt bound to hydroxysulphate minerals, muscovite and iron and manganese oxyhydroxide minerals and nickel is controlled by hydroxysulphate minerals, and manganese and iron oxyhydroxide minerals, as paste pH ranges ascend. Furthermore, at all paste pH ranges, pyrite was the main source of cobalt and nickel. These results were in agreement with the sequential extraction method and also previous experimental investigations, which confirms the performance of applied improved correlation analysis.