Back to basics: Restarting a high-grade gold producer in Yellowknife Brian Malahoff, the director of Sixty North Gold Mines Ltd., on a tour of the Mon Property in August 2017.
D
uring the initial staking rush in Yellowknife in the 1930s, a high-grade quartz vein was discovered outcropping along the side of a hill 45-kilometres north of Yellowknife, NWT. Subsequent exploration attempted to trace a planar vein model dipping to the west with limited success. In 1988, the property was optioned from Cominco and the folded nature of the vein was first defined. Drilling to intersect the eastdipping east limb to the south of the surface showing and mining in 1989 extracted 2,300 tonnes grading 18.3 gpt gold (diluted) from 15 metres of elevation in the east stope. In 1991, the central adit was excavated, and the well-exposed western limb was undercut. Over the next six years, 12,500 tonnes grading >27 gpt gold was mined, also from 15 metres of elevation and milled on site. In 2012, a three-dimensional model was constructed and the multi-ounce
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grades at the fold nose were shown to be consistent over the mined length of 75 metres, open to south, with lower grade gold values being found as one moves away from the hinge zone. Sixty North Gold Mining is earning a 100 per cent interest in the property from New Discovery Mines Ltd. by making $6 million in expenditures developing the property. The overall size, grade and form of the mineralization, as well as its host rock assemblage is similar to the Discovery Mine (located 50 kilometres to the north) where onemillion tons of ore were mined and onemillion ounces of gold were recovered between 1949 and 1969. The project is permitted to operate at 100 tpd similar to what the Discovery Mine and Con Mine started at. At surface, Sixty North has sampled the crown pillar of the hinge zone over 45 metres with results shown in Figure 1.
Figure 1: Trench Intersection Au Grade (metres) (gpt) 17-1 0.28 20.3 0.50 3.4 17-2 0.50 688.8 0.80 273.1 0.50 2.6 17-3 0.40 5.6 0.60 15.9 17-4 0.40 1.8 17-5 0.50 8.4 17-6 0.50 4.9 0.50 390.0 0.60 3.0 17-7 0.50 16.3 0.90 1.2 17-8 0.90 143.9 17-9 0.50 65.0 0.50 311.6 0.70 198.8 17-10 1.00 60.2 0.90 27.7
