Geo-spatial techniques to assist in the management of tailings dams

The 1994 Merriespruit disaster at the Harmony gold mine near Virginia in South Africa, in which 17 people were killed when a tailings dam collapsed, led to the inception of the Pinotage project. The project was undertaken to develop, implement and verify a process to identify and locate drainage ponds on tailings dams. Spot imagery of the study area was used, supported by GPS recordings and field surveys for improved accuracy and verification. Image registration, masking and classification were combined and adapted for this application. Masking eliminates seasonal radiometric variations. The classification procedure, with GPS support, accurately identifies drainage ponds. Once performed for a geographical area, the processing time can be reduced by two thirds. The approach offers an operational procedure that can be used by tailings dam engineers and managers to help prevent another tailings dam disaster.