Housing and population sprawl near tailings storage facilities in the Witwatersrand: 1952 to current

Abstract

Mining, tailings storage facilities (TSFs), dust pollution and growth in residential housing development are synonymous with the Witwatersrand, South Africa. Encroachment of housing onto land close to TSFs, i.e. areas rendered marginal because of the dust hazard and risk of structural failure, has continued unabated for decades, intensifying human exposure to windblown mineral dust. Recent research indicates that the finer milling used for modern gold extraction results in aeolian dust emanating from the TSFs which contributes to a higher proportion of inhalable particles in the source material. Air quality dispersion modelling, validated by ambient aerosol monitoring campaigns, indicates that episodic dust events generate particulate matter (PM10) and, specifically, quartz dust concentrations that are unhealthy at distances of up to 2 km downwind from TSFs. This contribution documented residential development from 1952 to 2011 (using historical aerial photographs, census data from 2001 and 2011 and ancillary information) to determine the population exposed to dust emanations from the TSFs. Using the images, land use was classified into residential areas, TSF footprints and open areas, onto which a series of 500 m buffer zone contours were superimposed. The resulting statistics were used to assess the populations exposed to dust hazard within the defined buffer zones. Overall, housing development has experienced a growth of approximately 700% since 1952 at a rate of 14% per year. Analysis of recent monitoring campaign data has confirmed multiple occurrences of quartzrich inhalable dust in residential settings at levels that exceed occupational health standards, extrapolated to values for population exposure.

Geochemical and Mineralogical Characterization of Gold Mine Tailings for the Potential of Acid Mine Drainage in the Sabie-Pilgrim’s Rest Goldfields, South Africa

“…(Table 1) in excess of South African guidelines soil screening levels, National Norms and Standards for Remediation of Contaminated Land and Soil Quality in the Republic of South Africa [8]. Thus, some of the exposed mine tailings may create hazards to local communities residing near the mine tailings [9]. This is likely to result in as poisoning through water pollution, dust inhalation and contamination of the food chain as especially evident in the Nestor tailings storage facility, which is highly weathered and exposed to erosion yet lying adjacent to Sabie River.…”

Respiratory Health in a Community Living in Close Proximity to Gold Mine Waste Dumps, Johannesburg, South Africa

“…Gold mine waste dump dust, specifically around the Witwatersrand area has a high crystalline silica content [3][4][5]. These mine waste dumps are mostly unlined and most are not vegetated, thus being a significant source of silica-rich, air-borne dust [2,3,6,7] consisting of fine particulate matter [7,8]. The reworking of gold mine dumps for further gold extraction using newer technologies has also resulted in an increase in the proportion of inhalable particles in the tailings material [8].…”

“…Residential encroachment in the areas surrounding mine dumps over a 50-year period may pose a great health risk for the individuals who live in these areas [8].…”

Ambient PM10 and Respirable Dust Levels Near Gold Mine Tailings Storage Facilities in South Africa

“…One of the main sources responsible for the generation of dust is the numerous gold mine tailings storage facilities (TSFs) covering the landscape of the Johannesburg/Witwatersrand area of South Africa. Although these TSFs represented an era of prosperity and affluence during the “Witwatersrand gold rush” in the 1800s, currently, these TSFs are seen as a public health concern . Mining in the Witwatersrand gold field has given rise to more than 270 TSFs, which collectively, covers a total area of 400 km 2 .…”