Environmental impacts resulting from gold mining tailings storage facilities within the West Rand area in South Africa

Abstract

Dust from gold mine tailings storage facilities (TSFs) have been noted to be of enormous challenge in the Republic of South Africa (RSA) owing to lack of successful rehabilitation of these structures. In the RSA, many of these communities such as Tudor Shaft Informal Settlement, Pennyville, Braamfischerville, Noordgesig,Diepkloof, Riger Park, Geluksdaal, Riverlea and Stilfontein comprised of historically marginalised ethnic groups (mainly poor black people) living in government-funded houses, informal settlements and retirement homes. Gold mining process produces waste through three main activities, namely mining, mineral processing and metallurgical extraction, releasing approximately 99% of extracted ore as waste into the environment. The disposal of mine waste, chiefly tailings, has of late, assumed an importance that transcends even the massive volumes of materials produced annually by mining operations. Aside from their significance in strictly engineering terms, TSFs receive intense regulatory attention and public scrutiny. People living downwind of mine tailings are exposed to the potentially inhalable trace metal and metalloid-bearing dust particles. Active TSF dams rarely have dust problems compared to dormant dams. Wind erosion can transport environmental contaminants such as metals and metalloids, pesticides, and biological pathogens, all of which are typically associated with finer atmospheric particles and tropospheric aerosols. These pollutants get dispersed by wind and lighter dust sized particles persist long enough to pose problems in distant areas, resulting in trans-boundary pollution. Several cases of dust emanating from tailings dams were previously lodged against mining houses in which mine dust exposures resulted in health impacts on the nearby communities. On windy days, windblown tailings material was reported billowing off the surface of the tailings thereby posing visibility impact within nearby roads. Many pathological effects may result from gold mine TSFs dust exposures, depending on mineral content, shape, size, chemical composition, levels, and duration of exposure of the dust particle. Human health effects resulting from quartz exposure has been confirmed as one of the main health related concerns in the Witwatersrand gold TSFs dust. Due to their height in physical design structure as well as the colour of tailings material, TSF structures are highly visible from key viewpoints posing significant visual intrusion and blocking clear lines of sight and from unsightly new landmarks. This study undertakes to assess the environmental risks of public exposure to the dust from gold mine tailings storage facilities within the Witwatersrand Basin. Both analytical and survey methods of dust deposition monitoring and experimental analyses will be employed to establish the precipitant dust and dust characteristic. This will further enable calculations of the extent of TSFs dust exposures of particulate matter. Dust sampling was conducted as per the American Society for Testing and Materials (ASTM D1739 1970) Standard Method for Collection and Analysis of Dust Fallout” (settleable particulates deposition dust) and several instruments were used to obtain to reflected results. Results of one-way ANOVA Test as per Table 4.15 above shows a correlation between TSF height and distance at which the particle travelled before reaching the ground confirmed a Welch P-value of 0.118, in which P-value > 0.005. Main finding of this study with regards to health exposure perspective is that even though most learners (70%) reside in formal housing made up of bricks and cement, they get exposed to dust from mainly mine TSF and vehicular movement as they spend time playing outside. This was confirmed by a strong association between dust and time child spend outside playing.