Beach Diamond Mining Design at the Rocky Namaqualand Coast

This study involved the design of beach diamond mining between Alexander Bay Harbour and the mouth of the Orange River on the west coast of South Africa. To mine this area entailed creating artificial sand beaches overlying rocky areas. Numerical modelling was conducted to predict the shoreline evolution resulting from sand feeding. The effectiveness of groynes to trap the limited natural longshore drift and sand dumped updrift of the groynes, was also considered. In addition, the structural design of these temporary groynes was carried out. Rock, concrete cubes and geotextile structures were investigated. The effects of different sand feeding rates and discharge locations in conjunction with varying groyne lengths and locations were simulated. Time-varying mineable areas were predicted. A temporary sand dike was designed to protect the mining activities from the sea. The potential physical impacts on the Alexander Bay Harbour and on the mouth of the Orange River were also investigated, as the high sand feeding rates advantageous to mining could potentially severely affect the harbour and river mouth.