Surface Runoff From An Area Undergoing Soil Rehabilitation After Bauxite Mining In Southeastern Brazil

Changing hydrological processes and soil characteristics are of major environmental concern in surface mining. Runoff may be the best factor for determining the efficiency of rehabilitation after this type of mining, and needs more in-depth studies, but the environmental factors require more attention in order to control that runoff. The objective of this study was to compare the runoff during post-mining rehabilitation after the extraction of bauxite with that before mining, and to identify the factors that most affect it. Runoff from before the mining operations and during the rehabilitation after those operations were collected in seven plots in the area of a bauxite mine in southeastern Minas Gerais State, Brazil. The physical-environmental and anthropic factors interfering with the runoff were characterized for both periods, and their results were submitted to principal component analysis to define the parameters, which most demand attention in the mining rehabilitation stage. This study provides the first records of runoff in the field in areas rehabilitated after surface mining in Brazil, where the runoff decreased (1.75-times or 42.79%) from 0.76 to 0.30% of the precipitation during rehabilitation, compared to the reference area. The total porosity, density, and resistance of the soil, associated with the maintenance of slope, surface roughness, and vegetation cover, are the factors demanding more attention during the rehabilitation stage of surface mining in order to minimize runoff.