Abstract
The impacts of dust fallout and PM10 ground level concentrations were investigated in this study due to the fact that a community located in the West Wits Basin, in Gauteng; near tailings storage facilities; had been complaining about dust, mostly during the windy season of July to October. The residents of this community started complaining immediately after a gold mining company suddenly closed due to being placed under provisional liquidation. In this study, the ability of Geostatistical techniques to assess local ambient air quality was investigated during the mine liquidation period. Geostatistics uses the theory of regionalized variables, that of producing the best estimation of the unknown value at some location within an area. Furthermore, dispersion modelling results from a previous study of the same site undertaken for the period of 2013 - 2017 were used to establish the extent of impacts from windblown dust. The results from the Kriging Interpolation were compared with the AERMOD model simulations of 2013-2017. In conclusion, this study found that Geostatistical techniques use statistics properties of dust samples to predict the probability of exceedance through interpolation maps, making it possible to visually assess the risk of population exposure to dust fallout and PM10. It was identified from the variation maps that at TSF6 there is an estimated 32 % chance of exceedance of the 40 μg/m3 NAAQS as shown by the indicator kriging. Furthermore, this study finds that there is a 54 % chance of exceedance of the 40 μg/m3 NAAQS around the area of TSF1. This study concludes that the use of geostatistics adds value to local scale air quality assessment for improved decision making for tailings storage facilities management