The diamond bearing gravels tend to be located within terraces in the last meter or two of sand as well as the materials caught within the gullied footwall. The bulk of this material is mechanically excavated with heavy digging, dozing and rock-breaking equipment through a process known as bulk excavation. The main function of bulk excavation is to extract all diamondiferous gravel from the bedrock footwall using 60 tonne excavators, 20 tonne excavators, hydraulic rock breakers and dozers to remove most of the diamondiferous ore. Bulk excavation makes it easier for the next process of bedrock cleaning to be done efficiently and with ease.
Similarly, to Bulk excavation, bedrock cleaning is done to extract the remaining diamondiferous gravel from the bedrock footing which is inaccessible to the machines to ensure no diamonds are left behind. The process of bedrock cleaning makes use of industrial vacuum suction units called transvacs. The transvac teams consist of bin and suction units and it is a people-based process that demands a reasonable degree of wholistic risk management.