Retreatability analysis of the Musina copper mine tailings in South Africa: an exploratory study

Abstract

In recent times, the potential beneficial uses of abandoned mine sites have been recognised and acted upon through the retreatment of tailings in order to win minerals of interest still available in economically viable concentrations. The most notable benefit (although not usually factored in financially) is that, once the tailings have been removed, the land has a greater potential to be developed further. The main aim of this study was to investigate the contents of copper and potentially harmful elements in the tailings of the Musina mine, an abandoned Cu mine in the northern Limpopo Province, in order to assess environmental hazards and to provide a first estimate of the feasibility of future economic rehabilitation. The concept of reclaiming was here seen in a broad way and ranged from the reworking of tailings or other residues to residential and/or recreational use. To quantify the potential economic importance and impacts of the metal content of the tailings, geochemical analysis of samples from auger holes and resource modelling were employed. Neutral to slightly basic pH values and very low concentrations of arsenic and lead showed that acid drainage and toxic groundwater contamination (apart from Cu itself) would not be a concern. Three-dimensional (3D) and two-dimensional (2D) models were applied to estimate the resource potential of the tailings dump. The models revealed that residual Cu in the Musina mine tailings is currently at 8555 tonnes. Accordingly, going forward, we recommend a formalised geometallurgical study to assess the economic feasibility of extracting Cu, with a view to reworking the copper tailings dump. It is very important that this tailings dump be mined in future, in order to extract all Cu and ensure that the sterilised land (up to 95 ha) can be used for other purposes.

The Biodiversity, Food Security, and Poverty Nexus in the Musina-Makhado Special Economic Zone of South Africa

“…The EIA and two invertebrate studies conducted for the MMSEZ failed to address the widespread use of natural resources by local communities for food, water, fuel, medicine, and cultural practices. During the Covid-19 pandemic, when sampling for the second invertebrate study by Singo (2021) was conducted, nature-based livelihoods from Pretoria northwards to the site of the MMSEZ and beyond to the Zimbabwean border were evident. Roadside hawkers were observed selling bundles of wildsourced Artemisia afra, a traditional remedy for flu (Ramalevha and Thompson 2020).…”

“…Considering 127 women and three men were found camping and bulk collecting mopane worms on a single farm near Musina in the Limpopo province (Taljaard 2019), the public participation process of the EIA should have identified mopane worm users as I&APs. The substantial body of literature documenting the importance of mopane worms as a nutritional food and a source of income (Baiyegunhi and Oppong 2016;Egan et al 2014;Makhado et al 2009;Sekonya, McClure and Wynberg 2020;Taljaard 2019) was also excluded from the EIA and the invertebrate reports compiled by Greffrath (2019) and Singo (2021).…”

“…This study undertook a secondary analysis of the 727 pages of the CRR compiled for the public participation section of the EIA (Semenya 2021) and the two invertebrate studies that should have included mopane worms (Greffrath 2019;Singo 2021). Several organisations and groups, including the Wildlife and Environment Society of South Africa (WESSA); World Wide Fund for Nature (WWF); Birdlife South Africa; the Endangered Wildlife Trust; South African National Parks (SANParks); and a group of local biodiversity experts, primarily from the University of Venda and local community groups, submitted comments on biodiversity impacts during the public participation exercise for the MMSEZ (Semenya 2021).…”

“…Many of the comments expressed broad concern about the rich biodiversity that South Africa would sacrifice. However, the WESSA's comments on the initial invertebrate survey (Greffrath 2019) and the recommissioned invertebrate study (Singo 2021) focused mainly on mopane worms, due to the invertebrates' importance in food security. This allowed the CRR and the specialist reports to be compared to independent academic studies on mopane worms and their contribution to the economy.…”

Progress, Challenges, and Perspectives of Bioleaching for Recovering Heavy Metals from Mine Tailings

“…Primary resources have been overexploited, and for sustainable development of resources, the development and utilization of tailings have become urgent. A survey of the copper content in tailings of the Musina mine, an abandoned copper mine in the northern Limpopo Province, showed that the residual copper currently stands at 8,555 tons [52]. As ore grades continue to decline, the byproducts of foam flotation are expected to produce copper tailings that still contain large amounts of unrecovered copper [53].…”