Assessing the regional structural geological setting as fundamental component of the dolomite risk management process
Dolomite stability investigations conducted within the confines of a pre-demarcated project area rarely take the regional structural geological setting into consideration. As such, the site selection process is very often conducted purely from a town planning or economic perspective, with no real consideration of geological aspects, or potentially hazardous dolomitic area. This study focussed on providing an updated regional geological and hydrogeological setting of the Klerksdorp-Orkney-Stilfontein-Hartebeesfontein (KOSH) area in support of the demarcation of regional indicated dolomite hazard zones for regional dolomite risk management purposes. These zones are aimed at supporting strategic decisions regarding future development planning, spatial development planning, and regional dolomite risk management. It is not intended to replace the detailed site-specific dolomite stability investigation, but rather emphasized the need to first obtain a regional overview of the structural geological- and hydrogeological setting of an area towards effective dolomite risk management. The findings of this study will serve as a foundation for future planning and detailed hazard determination across the KOSH-area as part of a regional Dolomite Risk Management Strategy. An initial sinkhole and subsidence database was also compiled as part of this study across the KOSH-area and correlated in terms of structural geological controls. No previous sinkhole and subsidence database or statistical information was available for this area. A final updated geological map, together with the demarcation of dolomite land and distribution of ground movement events across the area has been compiled. This served as the basis for the demarcation of the indicated regional dolomite hazard zones. The performance of the regionally demarcated indicated dolomite hazard zones were tested on a local scale by means of a conventional detailed dolomite stability investigation.