When the call came in from Granges Exploration to oversee a drill program in Manitoba, the ex-Hudson Bay Mining and Smelting project geologist accepted under two conditions. The property had to be near Flin Flon and also within view of Hudson Bay’s towering smelter stack, the most prominent landmark in the region.
Although he had spent most of his career exploring for base metals and had never seen visible gold in drill core before, he knew exactly what it was when the discovery was made in 1984.
Now, three years later, Granges and joint venture partner Abermin Corp. have developed and officially opened the Tartan Lake project, the only primary gold producer in the area, which just proves that sometimes nice guys do finish first.
There’s an interesting parallel between Flin Flon and the Timmins camp in Ontario which is probably worthy of comment. Until the massive Kidd Creek base metal discovery in the early 1960s, Timmins was viewed purely as a gold camp. Its Manitoba cousin, on the other hand, started from the opposite direction but is now becoming a significant gold camp in its own right, suggesting the region’s mineral potential is still largely untapped.
Unlike its joint venture partner, Granges has long been associated with the region. Many of its staff are alumni of Hudson Bay which has mines and a large smelting complex at Flin Flon. Also, Granges has a 19.8% interest in the nearby Trout Lake mine which Hudson Bay operates. (The orebody was discovered by Granges.) It’s an exceptional polymetallic (with gold) mineral deposit and the most profitable operation for Hudson Bay which has been struggling with other base metal producers in the face of low metal prices.
The day before the official opening at Tartan, Granges held its annual meeting in Vancouver where President Mike Muzylowski noted the company has been transformed from “an exploration to a mining company.” (Not that exploration isn’t high on the company’s priority list — last year Granges spent $12.6 million in Canada and the U.S.) Mr Muzylowski told shareholders that three gold mines would be added to the company this year with 1987 production expected to be 40,000-45,000 oz and 100,000 oz in 1988.
Tartan Lake is currently producing at 250 tonnes per day and mill throughput is expected to jump to 350 tonnes by September and to 500 tonnes by year-end. At the higher throughput, gold output would be approximately 43,000 oz per year which will be split between the two joint venture partners. Capital cost for the project should be about $20.5 million all inclusive, said Gustav Hoberstorfer, vice- president mining. Financing no problem
An exuberant Abermin president, Roger Taylor, told The Northern Miner that Tartan “will put us into a cash flow position,” which at 500 tonnes per day would total about $4 million per year before tax at today’s gold price. Abermin’s share of project costs will be about $7 million, he predicted. The company has received an offer from a bank to debt-finance its participation but Abermin is evaluating other alternatives as well.
The property was brought into production quickly because construction time was a major consideration in mine and mill design. Work on the 15-mile access route from Flin Flon started in February, 1986, and was completed in just two months; the mill was finished in March, just 11 months after road completion. Although some tune up problems remain to be resolved, the facility is living up to expectations, The Northern Miner was told at the mine opening. Recoveries have been averaging 85% but they are expected to rise to 92%, said Mr Hoberstorfer.
The company considered direct cyanidation in its flow sheet but for environmental reasons decided to leach flotation concentrate which represents about one-17th of mill feed. The higher throughput rate (500 tonnes) will generate about 30 tonnes of concentrate which Granges feels is quite manageable. The incremental expansion to the higher rate is relatively inexpensive, about $300,000 in this case. Mill components flexible
Incidentally, the gold recovery system was designed by Coastech Research in consultation with Proton Systems (both of Vancouver) which installed the shops, offices, power, process facilities and related ancillary mill equipment. SALA Machine Works near Toronto provided the crushing, screening, grinding, flotation and gravity units.
Basic mill components are highly flexible and mobile, said Mr Hoberstorfer. The SALA rubber roller mill was particularly easy to mount and install “because its shell is loose.” And he conceded the mill was somewhat uncommon in the Canadian mining industry.
The underground mining operation is certainly impressive and the most mechanized of its size this reporter has ever seen. A cut-and- fill mining method is employed along with hydraulic backfill which maximizes ore recovery and helps get rid of tailings. Equipment utilization will no doubt improve when the mine is producing at capacity later this year. There is no compressed air system underground although portable compressors are available for stope and jack-leg drilling. Similar to Trout Lake
Mining equipment is mostly of Finnish manufacture and is similar to Trout Lake which improves the availability of spare parts for both mines. Operators are being trained to run the equipment which includes a twin-boom Tamrock Minimatic electro-hydraulic drill jumbo utilized in development headings and 35-tonne trucks for ramp haulage. Underground workings have lights for improved visibility.
The decline was developed in waste and few rock bolts had to be installed. But ground conditions were poor in the central ore zone which is highly sheared and acted as a conduit for ground water. The zone had to be grouted with 750 tons of cement (17,000 bags) at a cost of some $600,000 but it’s dry now. Old diamond drill holes were used to place the grout. Underground dilution depends on vein widths and Granges estimates it will vary from 10%-15%.
Ore grade values have been noted to 1,700 ft and the ramp is being extended to about 1,000 ft in depth to drill this area. Fill-in drilling in the central zone has shown slightly lower grades but there are more ounces because reserves have increased, said Granges. The economics of mining much deeper than this from the ramp is questionable so an internal shaft will eventually be required through to surface. More than likely the shaft would be an Alimak raise with skip compartments. Four-year mine life
Present mine life is four years, based on a 500-ton-per-day mill rate and reserves of 582,000 tons averaging 0.307 oz gold in the main zone. Operating costs are estimated at $175(C) per oz which is below the national average.
Manitoba Hydro constructed a power line into the mine from Flin Flon at a cost of $600,000 and the roadwork was completed for $1.1 million. Power costs in this part of Manitoba are quite reasonable although line construction is expensive, said Granges. Diesel- generated power is a major cost item in remote mining areas so cheap power is a big plus for Tartan.
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