Vancouver-based Integra Resources has received positive results from metallurgical testing of samples from its DeLamar and Florida Mountain gold-silver deposits about 160 km from the capital, Boise.
From six Florida Mountain oxide samples, recoveries of 83.3% gold and 39.7% silver were achieved in bottle roll tests. The same oxide sample composites had 72.4% gold and 23.4% silver recoveries after 23 days of a 63-day preliminary column leach test. Integra says the success of the column flotation tests indicate that the deposit could be successfully heap leached.
The deeper un-oxidized mineralization from DeLamar will probably be more amenable to flotation. Historical work demonstrated good recoveries in sulphide concentration, fine grinding and cyanidation.
Integra is working on a preliminary economic assessment for the DeLamar project due out in H2 2019. Several processing options will be considered.
The inferred resource for both Florida Mountain and DeLamar deposits is 154.5 million tonnes grading 0.45 g/t gold for 2.27 million contained oz. The silver grade averages 21.92 g/t for 108.5 million contained oz. The gold equivalent grade is 0.71 g/t or 3.5 million contained oz.
The historic DeLamar mine was closed in 1998 after producing 1.6 million oz. of gold and 100 million oz. of Senile.
(This article first appeared in the Canadian Mining Journal)