The underwater separation of diamantiferous marine gravels

Includes bibliography.
Three underwater separation devices have been designed, constructed, tested and analysed to determine their suitability for the underwater separation of diamantiferous marine gravels. The research facility where the devices were tested was constructed at the University of Cape Town's Hydrotransport Research facility. The first device tested was a converging elutriator which separates the oversize gravel from the smaller diamond-bearing gravel, using their varying particle settling velocities in an upward flowing fluid. The cyclosieve and spirosieve are two other choices that both use rotational flow to create a centrifugal force, which forces the gravel onto a screening surface. The test work carried out investigated the effect of various variable parameters on the separation efficiency of each device.