Recovery of gold from a free - milling ore by centrifugal gravity separator

In this study, the technical viability of the application of a Falcon Centrifugal Concentrator for the recovery of gold from ore was reported. The results of mineralogical analysis have revealed that gold with a size of 1-300 mm particles occurs predominantly in native form in association with quartz as free particles, and with sulphide minerals as inclusions and growths located in the grain boundaries. The results of gravity tests have indicated that 81% of the gold from the ground ore (-74 mm) can be recovered into a concentrate (Con.1) with a grade of 262 g/t Au at a 7.2% yield. A clean concentrate containing 1760 g/t Au at 33.8% recovery was found to be produced by the further enrichment of Con.1 via hand panning. Final tails assaying 2.5 g/t Au obtained after three recovery stages corresponded to a gold “loss” of 8.0% and a feed mass of 73.8%. These findings demonstrate the amenability of Mastra ore to gravity recovery using a Falcon Concentrator, probably as a pretreatment step ahead of cyanidation.