Secondary resources at abandoned mine tailings, Giyani Greenstone Belt, Limpopo Province of South Africa

Abstract

Mining waste are materials that result from the exploration, mining and processing of substances and can consist of natural materials, processed to varying degrees during the ore-processing and enrichment phases, and possibly containing chemical, inorganic and organic additives. Evaluation of the REEs potential of the Klein Letaba tailings dam was envisaged to assist in the containment at the currently un-rehabilitated mine tailings material. These tailings are a concern to the livelihood of nearby communities in the Giyani area due to their threat to water and soil quality. The methodologies used in this study consist of sampling, sample preparation and analysis using X-ray spectrometry technique and calculation of the tonnage of the tailings material using the Trapezoidal rule method. The results indicated that the REE abundance at the tailings dump in their decreasing concentration were Yb > La > Ce > Gd > Sm > Dy > Y > Er > Tb > Eu > Sc. The tailings dam was found to have significant levels of both LREEs and HREEs, which are above the upper continental crust thresholds. For instance, the HREEs Gd, Dy, and Yb were almost 10 times or more than the crustal abundances and this being 56, 46 and 17 mg/kg respectively. The LREEs and HREEs had also a total concentration 602 and 769 mg/kg respectively. The calculated volume of the tailings material was found to be 527,081 m3 and the tonnage was derived to be 1,291 349.0 tons of tailings material at the site. Consequently, the total LREEs and HREEs contained in the material was estimated to be 843 tons and worth re-evaluating. The paper uses REEs at this study site to illustrate how other un-rehabilitated sites can be re-evaluated and attract investment towards exploiting them and subsequently assisting in tailings containment. However, the REEs at Klein Letaba tailings dam was found to be uneconomic to exploit under the current prices and technology.