Ten 1-kg samples from the LP fault were processed in a standard 48-hour bottle roll test at 40% solids with a 1 g/L sodium cyanide (NaCN) solution. The samples contained material of various grades, host rock, sulphide content and alteration styles. The highest recovery rate, 99.2%, belonged to the samples with the highest grade, over 20 g/t gold. The mineralization is described as free milling and not refractory.
The LP zone samples that were tested represent the most mineralogically complex intersections drilled to date. They had higher accessory sulphide content than the zone’s average, but that did not have a measurable effect on recovery. More tests are underway on low-sulphide material.
Great Bear expects that a gravity gold circuit will result in good gold separation. The company does not think an autoclave will be needed in the flowsheet to treat LP fault ore.
Similar earlier metallurgical tests of samples from the Dixie Limb and Hinge zones had recovery rates between 88.3% and 97.5% of the gold.
Great Bear continues to drill high and very high grades at Dixie, ahead of an initial resource estimate expected early next year.
(This article first appeared in the Canadian Mining Journal)
