Mark Williams Johns, Peter James Tout and Grant - Mintek / Philemon Bundo and Andrew Moyo - Cluff Resources Zimbabwe Ltd.
Presented at: SAIMM/MMMA Symposium entitled "New Developments in the Extractive Metallurgical Industry" - Zimbabwe - February 1996

November 9th, 1998

The Freda Rebecca Gold Mine is situated near Bindura in Zimbabwe and processes some 100 000 tonnes of gold-bearing ore per month. A laboratory test programme was undertaken to quantify the deportment of the gold in the residue. The test programme included mineralogical studies, diagnostic leaching, gravity concentration and cyanidation. The results indicated that cyanide-soluble gold was present in the residue.

The mine decided to hire a 30 inch Knelson gravity concentrator to quantify the effect of the removal of coarse gold from the milling circuit. Samples were taken on the plant before and after the installation of the concentrator. The samples were used to quantify the amount of cyanide-soluble gold in the residue and the deportment of gold in the residue (gold associated with quartz, gold associated with sulphides and gold that is 'preg-robbed'). The gold distribution in the milling circuit, the gold distributions in the various size fractions, the gold lock-up and the amount of coarse gold recovered was determined. The effect of the removal of the coarse gold on the response of the cyanidation circuit (cyanide consumption and residence time) and the CIP circuit (equilibrium isotherm and mass transfer coefficient) were measured. The programme indicated a pay-back period of months, and hence the Knelson was purchased.

Download the full report below: