S Richardson, Councilfor Geoscience
Dolomitic rocks occur in the Limpopo, Mpumalanga, Gauteng, North West and Northern Cape provinces of South Africa.
Dolomite is a soluble rock type that gives rise to sinkholes and dolines if given sufficient time and triggering mechanisms, i.e. ingress water or dewatering. Development of sinkholes and dolines are potentially dangerous and can even result in loss of life and damage to property.
The objective of such a project is to have a comprehensive inventory/database of such events across South Africa. Sinkhole/doline data is sourced from municipalities, consultants, government departments and the Council for Geoscience files and reports, as well as from literature. As new events occur, they will be added to the database. Much of the data is incomplete and has gaps in the information, and improving and updating should be an ongoing process. Once such a database is available, it will be a useful tool for future research and investigations. The database will also serve to aid municipalities, consultants and developers when future development is considered. The database will be GIS based and will include XY coordinates, location descriptions, size, depth, date of occurrence, cause, geological formation, etc. for each sinkhole/doline event. The need for reliable sinkhole statistics is critical for future assessment of sinkhole risk.
A notable case of utilising sinkhole statistics for design and development is the recent Gautrain alignment, which crosses dolomitic land on its route through