QUEBEC – SGS Minerals of Lakefield, ON, has completed continuous pilot testing of a 12-tonne bulk sample from the Duparquet gold project 45 km northwest of Rouyn-Noranda. Quebec City-based owner Clifton Star Resources says the latest tests confirmed earlier bench scale tests.
The bulk sample graded 1.835 g/t Au, 2.2 g/t Ag, 1.16% S and 0.055% As, and was tested for amenability to pressure oxidation or creation of a simple high grade concentrate.
For the POX test, a bulk concentrate grading 26.8% was subjected to pressure oxidation followed by a cyanide leach. Overall recovery of gold was 92%. Further work, said Clifton Star, shows that the rate can be boosted to 94% by using a hot lime treatment after POX and before cyanidation.
For the high grade concentrate test, gold recovery from flotation averaged 86.5% in a concentrate grading 49.9 g/t Au, 50.0 g/t Ag and 31.4% S. When float tails were subjected to cyanide leach, the overall recovery rose to 91.9%, likely a saleable grade without further treatment.
A brief history of the Duparquet mine is available at CFO-star.com.