The use of factor analysis and acid base accounting to probe the speciation of toxic metals in gold mine waste

Abstract

The generation of acidic drainage has become pervasive over the years and toxic elements are released due to exposure to oxidising agents, unforeseen circumstances, and human interactions. Uncontrolled acidic mine drainage release can result in substantial ecological disruption in sensitive and productive receiving waters. This study probes the element mobility of gold tailings with regard to various zones identified, based on possible phenomena such as the natural water medium, or acidic and alkaline media using sequential extraction and multivariate analyses. Factor analysis results, coupled with mineralogy, were corroborated with acid generation potential to identify various relationships that exist and establish the efficacy of the research towards predicting acid mine drainage generation potential. The statistical analysis was able to establish that pH or acidity, Fe ions, Ca 2+ and Mg 2+ played a major role in the released metals. Out of the four factors (80.8% accounted for) identified in factor analysis results for water fraction (WF), Fe contributed to three factors which showed the presence of Fe ions (assuming Fe 2+ and Fe 3+ ) responsible for the increased acidity of the tailings. The net acid producing potential and cumulative net acid producing potential showed that overall; the tailings would generate acidity due to the high presence of leachable sulphides. The trends observed in the carbonate phase indicated that despite the posit of acidity, the tailings contain a considerable amount of neutralising agent to serve as a buffer.