“Dolomithic subsoils” describe areas in South Africa underlain directly or at a shallow depth (i.e <100m) by the rock type dolomite. Dolomitic rock is composed of the mineral dolomite, which is a carbonate of calcium and magnesium. Dolomite is water soluble i.e dolomite dissolves in water.
Rainwater and percolating groundwater seeping in through joints, fractures and fault zones can lead to the dissolution of dolomite and in turn collapsing of this dolomite rock into caves or voids resulting in catastrophic ground movement on the surface such as sinkholes or dolines.
The Centralized Dolomite Risk Management Strategy devised by the Department of Public Works for infrastructure located in dolomitic subsoil forms and integral part of Pro-Plan Consulting Engineers approach to the design and implementation of projects in dolomithic areas such as Merafong City, Mogale City, Randfontein, Venterspost and Westonaria.