KIERENS

near Malartic, Que., could become slightly larger if a feasibility study on the adjoining Norlartic property pans out. Aur Resources, which planned to pour 24,000 oz (750,000 g) of the yellow metal at a cost of $225 (us) per oz this year, has run into problems finding a mill to treat its ore.

Despite not having a mill to process its ore, Aur has 53 workers at the Kierens mine working two shifts per day, five days a week, and have been averaging 22 tons (20 tonnes) per manshift. And exploration work continues on the adjoining Norlartic property.

Ore reseves in all categories between the 250-ft (75-m) and the 1,300-ft (390-m) levels in the Kierens mine total 1.2 million tons (1.1 tonnes), averaging 0.21 oz (6.5 g) gold per ton. But dilution brings down that figure to 0.17 oz (5.8 g) per ton by the time the ore reaches the mill stockpile. There are about six years of reserves indicated by drilling so far.

The mine is a simple, low-cost, cut- and-fill operation. Four jci and one Wagner 1/2-cu-yd load-haul-dump machines are used to muck ore in the narrow, 1-m-wide stopes. Backfill material is hydraulically placed sand, so the miners have been putting down timber planking before taking a round, and then mucking off those planks. Millholes are lined with 1/4-inch steel sections.

The muck is broken by a Rammer hydraulic hammer operated over a grizzly, the openings of which measure 30.5×35.5-cm. The ore is then trammed about 1,260 m in 4-ton (3.6-tonne) cars on the 1,300-ft (390-m) level and hoisted up the Norlarctic shaft in two 2.5-ton (2.3- tonne) skips.

“We’ve gone as high as 75 skips per shift,” chief engineer Keith Boyle said, “so we could easily hoist 730 tonnes per day. But we figure on 770 tonnes per day if everything proves out. The Norlartic orebody should be ready to mine about one year from now.”

The Norlarctic mine is a former producer which mined ore up to 20 ft (6 m) wide compared with the 6-inch to 4-ft (15-cm to 1-m) widths of the Kierens deposit. “The orebody is much more lensoidal on the Kierens property,” chief mine geologist Edmund Stuart said. Ore in the Kierens mine is grouped into two types: low grade, discontinuous lenses averaging 0.15 oz gold per ton (5.1 g per tonne) and a strongly silicified, corbonatized, vein-type zone containing up to 2% pyrite. The latter ore type averages 0.3 oz gold per ton (10. tonne). Two lenses, the l lens and the h lens, are being developed. A 210-m drift has been driven on the 1,300 level and 14 crosscuts have been driven every 15 m into the zone. The first raise in the zone was being driven at the time of our visit in August. It was up about 30 m. The last reserve estimate in the zone was 350,000 tons (320,000 tonnes) of 0.1 oz (3.4 g) gold per ton.

A ramp was also being driven below the 1,300 level towards the h lens. The first sublevel was to have started in September. The latest reserve estimate for this zone was 340,000 tons (310,000 tonnes) of 0.13 oz gold per ton (4.5 g per tonne).

Other gold zones in the area that look promising include the North Zone, where past production was about 90,000 tons (82,000 tonnes) of 0.3-oz (10.3-g) material. Aur is planning an underground exploration program to extend that zone from either the 1000 or the 1300 level.

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