Abstract:
Artisanal and small-scale gold mining (ASGM) has devastating impacts on different parts of the environment and is a source of environmental degradation and contamination. ASGM degrades water resources, contaminate soil, sediments and water and lead to serious land degradation problems. ASGM activities are also associated with socio-economic issues such as child labour, prostitution and health and safety concerns. Insufficient understanding of the environmental and social problems of ASGM in Giyani Greenstone Belt has led to lack of mitigation strategies to reduce such problems.
The main aim of this research was to assess and manage the environmental and socio-economic impacts of ASGM in Giyani Greenstone Belt. Remote sensing and GIS and Normalised Differential Vegetation Index were used to assess the effects of mining activities on vegetation cover. Assessment of the effects of ASGM on water, sediments and soil quality involved collection of samples in order to establish their physical and chemical properties. The concentration of toxic and trace metals were determined using Atomic Absorption Spectrometer (AAS) and X-ray Fluorescence (XRF) instruments. The pH meter was used to determine the pH level of the collected samples. Questionnaires, interviews and SPSS were used to assess socio-economic impacts of ASGM.
The study culminated in devolvement of NDVI maps and this was used to assess the effects of ASGM on vegetation cover. Results showed that the mining activities in the area had caused extensive environmental degradation due to serious removal of vegetation cover in the site. ASGM had serious effects on soil, water and sediments quality such as environmental contamination by toxic and trace elements. Soil samples were found with high concentration of As, Cr, Cu, Ni, Pb and Zn as compared to the recommended South African Soil Quality and WHO threshold values for plants. It was found that Klein Letaba had high concentration of Ba, La, V, and Ce above the World Soil Averages for plants. Sediments were heavily contaminated with Cr, Ni, Pb, Zn, As and Ba as compared to the recommended standards prescribed by US EPA and WHO. The pH of water, soil and sediments samples collected from both mining sites were found to be strongly alkaline which affects the plants growth as well as aquatic flora and fauna. Socio-economic issues such as child labour, injuries, educational problems, health and safety issues, police disturbance, creation of jobs and income generation were identified at mine sites.
ASGM had serious effect on vegetation cover through environmental degradation. ASGM also had serious environmental contamination by toxic and trace elements. ASGM had both positive and negative socio-economic issues at mining site which include employment
opportunities, income generation, occupational health and safety, police disturbance and arrests and the use of child labour. Mine site rehabilitation is recommended in this study to reduce environmental degradation. The remediation of contaminated area by concentrated toxic and trace elements should be applied at both mining sites. ASGM should be legalised to enhance positive aspects of the mining such as increase in income generation and creation of more employment opportunities. However, there should be enforcement of mining policies to reduce social and environmental problems.
