IMPROVING THE SIMPLE SLUICE BOX

The simple sluice box which has been in use for thousands of years for the recovery of heavy minerals, notably gold, is a complex system in terms of the physical mechanisms operating in the box and not well understood. The challenge is to improve the recovery of fine heavy mineral in the sluice box. The study described in this paper has increased our understanding of the mechanisms operating and in particular has established the importance of the behaviour of the settled gangue layer in the box. It also describes how the design of a sluice box can be modified to improve its effectiveness so that both grade and recovery of fine material can be improved.