This project was undertaken to evaluate the potential to economically recover additional metal values from the 4.6 million tons of Keno Hill flotation tailings which grades 3-4 oz/t silver, 0.8% lead and 0.9% zinc.
The study determined that the higher grade portion of the tailing, containing some 1.0 million tons at 5.35 oz/t Ag, responds well to cyanide heap leaching with a silver recovery of 50-60%. The testing data suggests that heap leaching is economically feasible at the current silver price of $US5.50/ounce and a currency exchange rate of 1.35 in favour of the US dollar.
The response to gravity and flotation concentration was poor.