Notice to the function of batch-operated sluices

Abstract

Sluices are common devices for the extraction of placer gold from gravels and sands. To maximize the outcome, a lot of investigations have been made, predominantly dealing with improvements of their technical construction. Recent similar works in a German gravel plant led to the conclusion, that the cycle time respectively the frequency of cleanups is also an important factor for the assessment of the recovery of a sluice-system. In contrary the available literature is low in fact-based data on this subject. Considerations and experiments led to the approach of modelling the enrichment of a sluice with gold by a saturation curve. From the variety of possible mathematical options, the form y = ax/(x + b) has been chosen for its simplicity. By feeding a test mat-sluice under industrial conditions and determining the mass and content of trapped gold after different times of feeding, a set of data pairs has been obtained. Using this data and the method of lowest error squares the parameters “a” and “b” of the assumed saturation curve have been identified. The significance of such an approach for recovery determinations and the gold extracting industry is discussed.