Bachelor Lake hopes for turnaround by 1988

According to the ancient adage, mines are made not found. Or to put it another way, it’s not finding but making the mine which separates the sheep from the goats of the mining world.

Few companies know that better than Bachelor Lake Gold Mines. A subsidiary of Quebec Sturgeon River Mines and member of the Coniagas group, Toronto-based Bachelor Lake has spent five years trying to turn its Desmaraisville, Que., mine, into a money spinner.

In the hope that milled ore grades and gold prices will eventually combine to make what Bachelor Lake thinks could be an “efficient little mine,” the company has continued to develop the property despite continuous losses.

Amid all the hoopla that goes with a brand new mine, a 500-tpd mill and reserves totalling 967,046 tons of 0.195 oz, Bachelor Lake poured its first gold at Desmaraisville July 10, 1982.

But the company ran into trouble almost immediately. While some 91,461 oz of gold were recovered between startup in 1982 and August, 1986, the project has been hampered by a high dilution factor.

By Dec 31, 1982, for example, when 45,497 tons of ore had been milled, the company said development rock and surface stockpile material cut average grades to 0.118 oz and that’s been the story ever since.

According to Bachelor Lake corporate relations vice-president Garfield Heyes, much of the explanation for that lies in the complicated geology in the region. The mine structure, including a 1,700-ft shaft and 11 development levels, have been built to follow a silicified dilation zone called the “main vein.” With a 430-m strike length at the Bachelor Lake property, the vein steepens with depth.

“When production started, we were sure that we’d mine at a grade of 0.185 oz, but from the 6th level up, we were drifting alongside the vein and we’ve experienced dilution all the way through,” he told The Northern Miner. “Most of the stoping has been developed from drifts alongside the vein.”

As reported in a recent operations summary, at an historical mill recovery level of 93.6%, the average mine production grade since 1982 is only 0.15 oz.

To achieve cash mine profitability at those grades, Bachelor Lake needed a gold price of $600 combined with a throughput of 450 tons per day, Heyes says.

In over five years, those magic numbers have combined only twice (in the first quarter of 1983 and the last six months of 1986) and after posting losses in December last year the mill was shut down due to a reduction in forward development work at the mine.

However, with the discovery of the new Vein structure and an emphasis on development below the 7th level where mine grades seem to be higher, Bachelor Lake is beginning to see some light at the end of the mine’s 1,700-ft production shaft.

Hopes of a turnaround are fueled by a steepening dip of the main vein system which has allowed the company to drift in the vein at levels 8, 9, and 10. “Now that we are drifting in the vein, we can maintain much better control and hopefully cut back on dilution,” said Heyes.

Exploration on the 7th level is also directed towards the 93 x 5.7-ft A Vein structure which, according to Bachelor Lake, averages 0.24 oz.

Recent reports say two holes located 400 ft northeast of any existing workings intersected 13.6 ft of 0.239 oz and 9.2 ft of 0.120 oz. between the 8th and 10th levels and the company is now testing the new structure from level six.

“Since the mine has a tremendously complicated fault structure, it has taken a number of years to understand it,” said Heyes who is hoping for an average mined grade of 0.17 oz in 1988.

Meanwhile the company is expecting to show an ongoing loss for the current quarter because it is still spending $2.5 million on underground development and exploration.

As part of that exploration program, the company is mobilizing a second drill to test an area west of the shaft for a possible angled continuation of the A Vein.

According to Heyes, 30 tons of ore has been hoisted from the 8th level east stopes where some 20,000 tons is already broken. That is being added to a surface stockpile of 30,000 tons of stope ore and development muck.

The company will be able to maintain throughput of 450 tons using ore from existing underground stopes which are under development. “We hoping to have eight to 10 working stopes between the eighth and ninth levels by 1988,” said Heyes.