Osisko Mining (TSX: OSK) recently finished drilling seven surface and 18 underground holes with bonanza grades at its Windfall gold project in Eeyou Istchee James Bay, Quebec. The results came from infill drilling within the current resource estimate.
Selected high-grade assays include:
Saying the infill program at Windfall continues to deliver “positive” results may well be an understatement. Osisko has already estimated the deposit to contain 6 million measured and indicated tonnes at 9.6 g/t gold, containing 1.9 million oz. and 16.4 million inferred tonnes at 8 g/t gold, containing 4.2 million oz.
The preliminary economic assessment for the project posits an after-tax net present value of C$1.5 billion and an after-tax internal rate of return of 39.3%. The after-tax payback period would be only 2.2 years.
Windfall is expected to produce 300,000 oz. of gold from ore with a diluted grade of 8.1 g/t gold annually for the first seven years of commercial production. The mill has a planned capacity of 3,100 t/d with gold recovery of 94.8%. The preproduction capex would be C$544 million including construction of a power line and a C$55 million contingency.
(This article first appeared in the Canadian Mining Journal)