Abstract:
Environmental degradation is a quite familiar factor of the mining industry that has been associated with South African mining industry from the beginning. The decommissioning of abandoned mines before the environment legislation, The National Environmental Management Act 107 of 1998 and the Minerals and Petroleum Resources Development Act 23 of 2002, was introduced is of great concern as the abandonment of mines without appropriate remediation and pollution monitoring was the result.
Soil erosion has been recognised as an environmental hazard that emanates from abandoned mines. This study seeks to assess the soil erosion hazard around Nyala abandoned mine. The modified method of Soil Loss Estimation Model for Southern Africa (SLEMSA), for assessing soil erosion hazard, was used to estimate the spatial variation of erosion to achieve the goal of the study. Parameters that were considered for the model include relief (Slope steepness, S & slope length, L), soil erodibility (Fb), vegetation cover (C) and rainfall erosivity (E). Soil samples were collected from the field and; sieve and hydrometer analysis was conducted to determine the erodibility factor value of the study area. The model was run in a GIS environment (ArcGIS) and the parameters were multiplied to generate a soil erosion hazard map for the abandoned Nyala mine area.
Results from the study indicated that 74.3 % of the watershed experiences low to moderate erosion hazard, with an estimated annual soil loss of 2.76 tons/ha/yr. The low rates of soil erosion in most parts of the watershed are associated with the low topographic ratio and low rainfall erosivity. The research demonstrated that the modified SLEMSA model used within GIS is a very useful tool as it enhances the capacity to assess and model the spatial variation of soil erosion hazard in a timeously and affordable manner.
