Natural Approach to Mined Land Rehabilitation

A major challenge of open pit mine operations is to efficiently dump the overburden waste material in a cost effective way. The traditional approach is to pile the overburden material in a large pyramid shaped "dump". The advantages of this approach are that the haul distances to the dump are minimized and the perceived "footprint " of the waste material on the natural surroundings is minimized. However, the landforms created by this approach are subject to significant erosion. Rainfall events lead to the loss of topsoil, the development of incised gullies and water channels on the dump and, at times, slope failures. This soil erosion affects the downstream channels by increasing turbidity, salinity and mineral content and introducing excess sedimentation. Mining companies build structures such as rock drains, contour banks and sediment ponds to mitigate this problem. However, over time, mines have found that these approaches often do not work and require the mine to constantly maintain the dump and its drainage structures. Many consider waste dumps unsightly and have found that they can rarely be used for the same purposes that existed before mining (e.g. agriculture). In 2000 a new GeoFluv (Fluvial Geomorphic) approach was introduced to a BHP mine in the USA to address the problems of traditional waste dumps. GeoFluv uses hydrological principles t