Second Saskatchewan gold mine

This province’s second gold mine, just a stone’s throw away from the first, is up and running. Jolu, owned 30% by Corona Corp. (TSE) and 70% by International Mahogany Corp. (VSE), is in the tune-up phase having processed 2,412 tons of rock at the time of a tour by The Northern Miner.

The 400-ton-per-day mill and mine is expected to produce about 50,000 oz of gold per year from proven and probable reserves of 627,000 tons grading 0.38 oz gold per ton. Although the majority of the project is held by Mahogany, this mine carries the stamp of Corona — first evident when one enters the staff camp named Royexville on a road sign. (Royex was the parent of International Corona before both companies were merged earlier this year).

Corona as project operator, has fast-tracked the development from a production decision in March to pouring gold in November. Mill construction began in June with the ball mills turning over in late October.

Although still in the tune-up phase, the operation has only encountered a handful of minor problems, mine manager Garry Biles told The Northern Miner. These included a broken shaft in the thickener tank which required replacing and a loosened bolt in the jaw crusher, which was quickly tightened thereby preventing more serious problems.

Importantly, initial mill recoveries “have exceeded Corona’s target recovery of 95%,” John Kazakoff, mill superintendent, explained. Although considerably more tonnage will have to be processed before Kazakoff can be absolutely confident about the metallurgical attributes of the ore, the early results are deemed quite satisfactory.

Mining essentially a sulphide- bearing quartz vein, a large amount of the gold, up to 50%, is recovered by the mineral jig circuit. The remainder is removed by a series of six carbon-in-pulp tanks. In early November, the jig tables had recovered approximately 100 oz of gold, Biles said. The heavy mineral concentrates grade about 60% gold before being fed into the bullion furnace for melting and pouring. The first pour of molten gold is scheduled for Nov 15.

Discovered in the summer of 1984, Jolu’s Rod main zone displays similiar geological characteristics as the neighbouring Star Lake gold mine. Star Lake, which began operating in early 1987, hosts a massive pyrite-rich quartz lense in a northeast striking shear zone. Northeast oriented shears offer the main target for exploration in the camp — and Jolu’s Rod main deposit is no different.

Rod main, and the smaller Rod south zone which is a sub-parallel splay, are associated with northeast striking structures. Gold, which can occur as coarse and free fractions, is predominently associated with pyrrhotite and pyrite, geologist Richard Kilpatrick explained. Displaying typical pinch and swell characteristics, the main vein reachs widths up to 20 ft in the 110 stope, examined by The Northern Miner.

The quartz host makes a sharp visible contact with the darker felsic intrusive wall rock, thereby making zone definition possible by sight. However, careful mapping and sampling is still required by the mine geology staff to ensure efficient blasting.

Following a test mining program last year, Corona has adopted a shrinkage stope mining method. This is considered the best way to deal with varying widths and erratic grades. In the 110 stope, for example, slashing was ordered to remove a large piece of vein left behind on wallrock. This type of hands-on approach is required to avoid excessive dilution and waste.

Little rock bolting was evident, an observation Biles said is due to good ground conditions in the mine. Also, no significant water in-flow problems were seen.

Access is via a decline ramp to the 275-m level. When completed, the decline will reach the 400-m level, which is the limit of current reserves. Once completed, stations will be cut enabling deep drilling below the lowest levels, Biles added. The Rod main and south zones are open at depth.

Total operating costs are estimated at $98.54 per ton. Of that mining is about $60 per ton, Biles said. That will translate to an average cost per oz of gold of $175(US) by the time the operation shuts down.

Tonto Mining, a contractor from B.C., has been on site since blasting the ramp portal, and will most likely sign a three-year agreement to mine out the deposit. Tonto is the busiest contractor in the La Ronge camp. The firm mines the Star Lake deposit and is responsible for the underground excavations on the nearby Fork Lakes gold deposit south of Jolu.

Additional mine development will be geared to the success of the geology department in defining additional reserves beyond the current 4-year life. At 400 m, the ramp is probably near its economic limit. “We’re getting a bit deep for a decline — there’s no question,” Biles agreed. The alternative will be a vertical shaft, which Jolu already has a head start on. Biles explained that a skip and hoist could be added to the ventilation shaft which has been sunk to a depth of 250 m. If upgraded, the shaft would have two compartments capable of hoisting rock and channeling air. Men and equipment would be transported to work stations through the decline ramp. If warranted the shaft would be commissioned by late 1990.