Abstract
Over the years, the mining industry has left behind a footprint. In the Limpopo province alone, over 800 abandoned and derelict mines have produced an enormous quantity of rock waste dumps, tailings and other associated mining infrastructure, collectively known as mine residue areas. In this province, no attention has been paid to the extent of heavy metal and other trace element concentrations and their potential impact on the environment and human health. There is an urgent need to identify the economic potential of rehabilitating such mine residue areas. The main aim of this study is to establish whether it is possible to reclaim the mining residues in an economically viable way for three abandoned mines in the northern Limpopo Province that serve as case studies. These mines are the Musina Mine (copper), Louis Moore Mine (gold) near Giyani and Nyala Mine (magnesite) in Zwigodini. The concept of reclaiming is considered in a broad sense, and ranges from the reworking of tailings or other residues to residential or recreational use. The study methodology of this thesis comprises four phases: In the initial phase, a desktop study was undertaken prior to the actual fieldwork. The aim was to obtain first-hand information about the three key sampling sites. Legal land access permissions were applied for and granted by the relevant land custodians. The second phase involved a reconnaissance survey (direct observation), the aim of which was to ensure that field activities such as drilling, logging and sampling could be conducted safely and productively. The other important intention of this visit was to identify all potential hazards, access points and sampling areas. In the third phase (field work), eight (8) auger boreholes were drilled on the Musina Mine tailings, twenty-three (23) surface samples taken at the Nyala Mine and ten (10) auger boreholes drilled on the Louis Moore Mine tailings. In addition, five (5) and ten (10) grab rock samples from rock dumps (low quality stockpile) were taken at Nyala and Musina Mines respectively. The auger boreholes drilled were logged and sampled. A total of one hundred and thirty (130) samples were taken. In the fourth phase (laboratory work), rock and soil samples and aqua regia leaches of tailings samples were analysed for major and trace metals as well as mineral abundances, using Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES), ICP MS, X-ray Diffraction (XRD) and petrography techniques in the University of Johannesburg (UJ) laboratory. Cross-checks were conducted externally by the Council for Geoscience (CGS) and Société Générale de Surveillance (SGS) laboratories. The results pointed, in principle, to the viability of reworking the rock dumps and tailings. However, at the same time, potential environmental risks were identified...
Ph.D. (Geology)