Mercury-Free Gravity Gold Recovery for a Village Circuit, Priced Against Whole-Ore Amalgamation: A Designed Circuit with a Recovery Budget

Design and first-principles calculation study of a mercury-free gravity gold circuit (sluice plus shaking table on the tailings, optional small centrifuge) priced against whole-ore amalgamation. SIMULATED, NOT MEASURED; nothing was built or field-tested. For 2 tonnes per day at 5 grams per tonne, the sluice-and-table circuit recovers 53.8 percent of the gold at $5.05 per gram recovered, the centrifuge version 64.4 percent at $6.41 per gram, and whole-ore amalgamation 31.9 percent at $8.71 per gram while losing 7.978 kilograms of mercury per year (10.01 grams per gram of gold, mostly to tailings). The gravity route's fine-gold loss is stated at full size: gold below 38 micrometres is 35.0 percent of the feed gold and the base circuit recovers only 16.6 percent of it.