A QUIET GIANT (November 01, 1988)

Scandinavian mining technology is playing a prominent role in Canada’s newest nickel mine. The mining method — longhole raise mining — selected for the bulk of the 2.58-million-tonne orebody under Namew Lake in northern Manitoba was pioneered at the Viscaria copper mine in northern Sweden. And many of the pieces of major underground mine equipment selected by operator Hudson Bay Mining & Smelting (HudBay) are being manufactured in Finland. Even the conceptual mill design and many of the components of that mill are imports from Finland. Many of the components of the mill equipment and all of the contract work on the mill were done by Canadian companies, though, according to Senior Project Manager Timo Niitti of Outokompu Oy.

When mine operator HudBay gets the mine and mill up and running at full tilt — treating 2,100 tons of ore per day — indications are that it will be very profitable indeed. But advanced technology is not the only cause for optimism. With an average grade of 2.44% nickel, the deposit is a natural money-maker. At today’s nickel prices, payback on this $70-million project could be as little as one year. Forty per cent of the concentrates produced will be the property of Outokompu Oy of Finland and the other 60% will belong to New York-based Inspiration Resources, HudBay’s parent. Inspiration has decided to ship its share of nickel concentrates to Sherritt Gordon’s refinery in Fort Saskatchewan, Alta., while Outokompu will send its share to Inco Ltd.’s facilities in Thompson, Man. When we visited the site in mid-September, crews were working flat out to reach full production, probably in March, 1989.

Renowned more for their zinc/ copper exploration and mining expertise in the Flin Flon-Snow Lake area, than for finding nickel mines, HudBay was as surprised as anyone in April, 1984, when it found nickel at Namew. Nickel mineral violarite showed up in the first drill hole pulled on to the ice on Namew Lake that spring. But it was the last hole of the season and field geologists didn’t recognize the relatively obscure nickel-bearing mineral right away. News of the discovery came from the assay office, according to Chief Exploration Geologist Ted Baumgartner.

When drilling resumed from the ice the following winter, HudBay was cutting some big intersections by the seventh and eighth holes. By then it was evident they were into a decent nickel discovery — the first in the Flin Flon-Snow Lake Greenstone Belt. The deposit is in the granitic Precambrian rocks buried under a thin layer of Phanerozoic sediments — a geological terrain relatively new to the company’s exploration geologists. The sequence of events leading up to the discovery is a textbook example of geophysical exploration using airborne EM-30, ground induced-polarization and anomaly drilling.

As important as the discovery was to the company, details of the find were not made public until April, 1987, when then-project geologist (now mine geologist) James Pickell presented a paper in Saskatoon detailing that sequence of events. That same paper was presented in Toronto, Ont., at the annual convention of the Prospectors and Developers Association of Canada the following month. By then, HudBay had tied up most of the ground in the area. It accomplished this by putting up a $25,000 bond for four permits in the area — three in Manitoba and one on the Saskatchewan side of the border. This regulatory quirk, unique to Manitoba and Saskatchewan, gives exploration companies three years to assess a large chunk of ground, staking claims on ground they wish to keep. This luxury obviates the staking rush by junior companies around any major discovery as is common practise in other parts of the country.

By drilling about 60 holes, HudBay has outlined a mineable reserve of 2.58 million tonnes in a gently-dipping zone 3 to 30 m thick, grading 2.44% nickel and 0.9% copper, with significant amounts of platinum and palladium. At a mining rate of 2,100 tons per day, that’s enough for five to six years of production.

But HudBay hopes more nickel orebodies can be found in the area. About 25% of the company’s 1988 exploration budget of $6.8 million was spent examining the claims HudBay has retained in the area. About half of those claims have received a first pass look and some anomalies have been drilled, Baumgartner says.

“We think the potential for finding more nickel is good,” Vice-president Exploration Alastair Walker says. “There is bound to be more if the Lynn Lake area (further north) is a good example.”

The ore at Namew occurs as a high- grade aplite breccia cemented with sulphides at the top of a lower-grade ultramafic pipe disseminated with sulphide blebs. The deposit dips at about 48 (see Core Shack, page 14).

HudBay quickly built an access road into the property from an unpaved road that goes into the Sturgeon Landing Reserve on Namew’s north shore from Highway 10. And with Aurora Quarrying as contractors, HudBay has rapidly developed the deposit on two main levels from a 3-compartment, rectangular shaft driven for access on the shore of Namew Lake. That shaft is 415 m deep. The main levels were driven 200 m apart vertically, and an intermediate level (about halfway between) is planned. All levels will be connected with an internal ramp driven at a slope of 14%.

While drifting on the 320-m level, crews encountered a major water- bearing fault zone intersecting the drift at about 30 . The zone was encountered about 100 m from the ore zone. Crews have successfully drifted through the zone, but development work was delayed in order to set up a 3,000-gal-per-min flow test. This should help determine the source of the water and the capacity of the system. A number of holes have been drilled into the fault zone and water will be pumped back to the shaft in a 12-inch pipe. Water was encountered in the shaft as well, at flow rates of only 40 to 50 gal per min. Expectations are that there will be some addition to the anticipated mining costs as a result of this flow of water; precisely how much depends on the long-term deliverability of the water-bearing unit.

At the time of our visit in mid- September, four crosscuts had been driven through the orebody on the 120-m level. A raise bore machine was to be set up in one of these cross- cuts (designated stope 93) and a pilot hole was to begin drilling in about two weeks. That pilot hole would be 200 m long, drilled in ore next to the hanging wall at an angle of about 45 , breaking through on the 320-m level. From there, a reaming head 3 m in diameter would be attached to the drill string and the hole reamed over its entire length at a rate of about 3.5 m per shift. By the end of November, this raise was to have been complete, providing ore for the start-up of the mill, which at the time of our visit was very close to being turned over.

HudBay plans to mine the first slice of ore by lowering an electric-hydraulic longhole rig down the lower half of this raise and drilling a fan of holes two inches in diameter every 1.5 m at right angles to the dip of the deposit. By blasting two or three of these rings at a time into a crosscut on the 320-m level, a single blast from this stope alone would be enough to provide sufficient ore for 24 hrs of mill feed. Each of these stopes contains about 280,000 tons of ore — enough for half a year’s production. Rock mechanics engineer Alan Moss at Golder Associates in Vancouver, B.C., designed the dimensions of the vertical stopes. They are typically 20 m long and 10 m wide.

Two different mining methods are to be used at Namew, depending on the mining width. Longhole raise mining, described above, will be used in 21 primary and secondary stopes between the 120-m level and the 320-m level where mining widths are as high as 27 m. Average widths are 12 m to 14 m. Drift and fill mining will be used in the high-grade, upper portion of the orebody where mining widths average only 2.4 m. In the raise mining area, the bottom 100 m will be mined in alternating stopes and then filled with crushed, cemented limestone as backfill. Then the upper 100 m of the stope will be mined (from the 109-m level to the 120-m level) with ore being mucked from the cemented sandfill in the stope below. Secondary stopes (or pillars) between the primary, mined-out stopes will be mined in the second pass of mining. Overall, extraction should be about 94%, dilution 15%.

Pneumatic wagon drills, manufactured by Atlas Copco, will be used for production drilling in the drift and fill stope above the 120-m level. The mine has purchased two new 2-boom jumbos, equipped with HD 125 drifters, from Boart Canada for development work. HudBay has signed a one- year cost-per-foot contract to supply bits and steel with Kenroc.

In the raise mining stopes, Thyssen Mining & Construction has been contracted to drive the raises. Although HudBay would like to have accuracies of 1% to minimize development work in the draw points, Thyssen has guaranteed accuracy of 2%. Ground conditions are expected to be so good in the strong gneisses in the hangingwall that only occasional ground conditioning will be necessary in the completed raises to accommodate the manned longhole electric-hydraulic drill jumbos (Solo H600R) and charging wagon being manufactured by Tamrock in Finland. HudBay will be purchasing two of these drill rigs (at a cost of about $500,000 each) and one charging wagon (costing $330,000).

Three scoops, equipped with 5-cu- yd buckets, have been purchased from U.S. manufacturer Wagner Equipment. They will be operated by remote controls at the draw points to the raise mining stopes. A smaller scoop may be necessary for mucking in the drift and fill stopes.

Two used Eimco-Jarvis-Clark haulage trucks, with a 27-ton capacity, have been brought in from HudBay’s Trout Lake mine, which has replaced its fleet with larger, 40-tonne units (see separate story, page 33). A third truck, which will probably be purchased new, is needed on the 320-m level, says Senior Mine Engineer Gerald Beauchamp.

Once production begins on a 24-hr basis, 136 people will be employed at the mine/mill complex. Each employee will work a 12-hr shift, four days per week, and will have the option of staying in camp for those four days at company expense. Or he can travel back and forth to Flin Flon every day.

Ore will be trucked to the ore pass on the 320-m level, which feeds a 600-ton storage bin above a new jaw crusher. The ore is crushed to minus 6-inches and stored in a 400-ton bin below the crusher. One 10-ton skip will be loaded in the loading pocket and hoisted to a 1,000-ton storage bin in the headframe on surface.

The ore will be conveyed to the crusher building where two used cone crushers from a concentrator in Whitehorse, Y.T. (a 4 -inch standard and a 5 -inch short head, both from Siemens ag) will crush the ore to minus -inch before going to the mill. The capacity of this part of the milling circuit will depend on the moisture content of the ore and on how easily the material breaks. All components in the crusher building are enclosed with ventilation hoods and blowers to provide a dust-free working environment. A single operator will be needed to run the operation from a control booth in the crusher building. Alternatively, the crushing circuit can be run from the main control room in the mill.

This control system is the showpiece of the mill. Conceptual design of the mill was done by Outokompu from offices in Toronto. But detailed engineering was carried out by Kilborn Engineering with sub-contract work going to a number of companies. A multi-loop Proscon computer system and an Outokompu 30 on-stream analyser (the first of its kind built from the ground up in Canada) will be used by five employees to assist them in running and maintaining the entire milling process. A somewhat similar system is operating in Inco Ltd.’s mill in Thompson, Man., according to Namew Mill Superintendent Gil Labarre. But the Thompson system is an add-on, designed to marry a number of component mill control systems. The system at Namew will provide an endless series of possibilities for mill operators in obtaining the most efficient results from the crushing, grinding, flotation and de- watering circuits. The system features two modes of operation — one for day-to-day operations and one for experimental simulations. “You don’t need a lot of training to learn the system and you can generate numerous reports,” Labarre says. “Probably in the long run an integrated system is cheaper because you’re not marrying a number of units all over the mill.” An added feature for mill operators will be a radio communication system built into their hard hats. Operators on the floor of the mill will be able to stay in contact with the operator in the control room. The radio operates on two channels — one for operations personnel and one for maintenance.

One of the interesting aspects of this mill is the thought that has gone into the design, starting from the plant layout right on up to the computer control system. The main control room separates the noisy grinding circuits on one side from the relatively quiet flotation and filtering circuits on the other. A clear view of each circuit is provided from the second- floor room and a splended view of the lake through the north wall window lends an added touch. Down on the mill floor, even the sumps are organized to drain from each of the rougher, scavenger and de-watering circuits. And all pumps are arranged along a central aisle, easily accessible by forklift and a 15-ton overhead crane manufactured by Kone.

Interesting new pieces of equipment in the mill include two radioactive belt scales — one installed before the cone crushers and one before the rod mills. These units, manufactured by Berthold of West Germany, are small enough so that they do not occupy too much space, and their performance is not affected if installed on an inclined conveyor belt. At the dewatering end of the circuit are two Enviro-clear thickeners — deep, vertical thickeners, which again do not take up excessive space in the mill. These thickeners are also used in HudBay’s zinc and copper mills in Snow Lake and Flin Flon.

Concentrates from the Namew mill are expected to grade about 17% nickel. Although the company’s metallurgical projections are based on bench-scale tests on drill core, Outokompu’s Niitti is confident the mill will perform better than what is anticipated from those tests. Concentrates will be trucked to a load-out facility at Atik, Man., where 60% will go north to Thompson and 40% will go south and then west to Fort Saskatchewan.

Tailings from the flotation circuit in the mill will be pumped to the tailings area directly south of the mill. Dams around the relatively flat area are high enough to contain two years of tailings. They will be raised to accommodate more tailings as mining progresses. Overflow will go into a small clarifier pond, then into Namew Lake.

Waste rock from underground development headings is being crushed for building surface roads.

Scandinavian mining technology is playing a prominent role in Canada’s newest nickel mine. The mining method — longhole raise mining — selected for the bulk of the 2.58-million-tonne orebody under Namew Lake in northern Manitoba was pioneered at the Viscaria copper mine in northern Sweden. And many of the pieces of major underground mine equipment selected by operator Hudson Bay Mining & Smelting (HudBay) are being manufactured in Finland. Even the conceptual mill design and many of the components of that mill are imports from Finland. Many of the components of the mill equipment and all of the contract work on the mill were done by Canadian companies, though, according to Senior Project Manager Timo Niitti of Outokompu Oy.

When mine operator HudBay gets the mine and mill up and running at full tilt — treating 2,100 tons of ore per day — indications are that it will be very profitable indeed. But advanced technology is not the only cause for optimism. With an average grade of 2.44% nickel, the deposit is a natural money-maker. At today’s nickel prices, payback on this $70-million project could be as little as one year. Forty per cent of the concentrates produced will be the property of Outokompu Oy of Finland and the other 60% will belong to New York-based Inspiration Resources, HudBay’s parent. Inspiration has decided to ship its share of nickel concentrates to Sherritt Gordon’s refinery in Fort Saskatchewan, Alta., while Outokompu will send its share to Inco Ltd.’s facilities in Thompson, Man. When we visited the site in mid-September, crews were working flat out to reach full production, probably in March, 1989.

Renowned more for their zinc/ copper exploration and mining expertise in the Flin Flon-Snow Lake area, than for finding nickel mines, HudBay was as surprised as anyone in April, 1984, when it found nickel at Namew. Nickel mineral violarite showed up in the first drill hole pulled on to the ice on Namew Lake that spring. But it was the last hole of the season and field geologists didn’t recognize the relatively obscure nickel-bearing mineral right away. News of the discovery came from the assay office, according to Chief Exploration Geologist Ted Baumgartner.

When drilling resumed from the ice the following winter, HudBay was cutting some big intersections by the seventh and eighth holes. By then it was evident they were into a decent nickel discovery — the first in the Flin Flon-Snow Lake Greenstone Belt. The deposit is in the granitic Precambrian rocks buried under a thin layer of Phanerozoic sediments — a geological terrain relatively new to the company’s exploration geologists. The sequence of events leading up to the discovery is a textbook example of geophysical exploration using airborne EM-30, ground induced-polarization and anomaly drilling.

As important as the discovery was to the company, details of the find were not made public until April, 1987, when then-project geologist (now mine geologist) James Pickell presented a paper in Saskatoon detailing that sequence of events. That same paper was presented in Toronto, Ont., at the annual convention of the Prospectors and Developers Association of Canada the following month. By then, HudBay had tied up most of the ground in the area. It accomplished this by putting up a $25,000 bond for four permits in the area — three in Manitoba and one on the Saskatchewan side of the border. This regulatory quirk, unique to Manitoba and Saskatchewan, gives exploration companies three years to assess a large chunk of ground, staking claims on ground they wish to keep. This luxury obviates the staking rush by junior companies around any major discovery as is common practise in other parts of the country.

By drilling about 60 holes, HudBay has outlined a mineable reserve of 2.58 million tonnes in a gently-dipping zone 3 to 30 m thick, grading 2.44% nickel and 0.9% copper, with significant amounts of platinum and palladium. At a mining rate of 2,100 tons per day, that’s enough for five to six years of production.

But HudBay hopes more nickel orebodies can be found in the area. About 25% of the company’s 1988 exploration budget of $6.8 million was spent examining the claims HudBay has retained in the area. About half of those claims have received a first pass look and some anomalies have been drilled, Baumgartner says.

“We think the potential for finding more nickel is good,” Vice-president Exploration Alastair Walker says. “There is bound to be more if the Lynn Lake area (further north) is a good example.”

The ore at Namew occurs as a high- grade aplite breccia cemented with sulphides at the top of a lower-grade ultramafic pipe disseminated with sulphide blebs. The deposit dips at about 48 (see Core Shack, page 14).

HudBay quickly built an access road into the property from an unpaved road that goes into the Sturgeon Landing Reserve on Namew’s north shore from Highway 10. And with Aurora Quarrying as contractors, HudBay has rapidly developed the deposit on two main levels from a 3-compartment, rectangular shaft driven for access on the shore of Namew Lake. That shaft is 415 m deep. The main levels were driven 200 m apart vertically, and an intermediate level (about halfway between) is planned. All levels will be connected with an internal ramp driven at a slope of 14%.

While drifting on the 320-m level, crews encountered a major water- bearing fault zone intersecting the drift at about 30 . The zone was encountered about 100 m from the ore zone. Crews have successfully drifted through the zone, but development work was delayed in order to set up a 3,000-gal-per-min flow test. This should help determine the source of the water and the capacity of the system. A number of holes have been drilled into the fault zone and water will be pumped back to the shaft in a 12-inch pipe. Water was encountered in the shaft as well, at flow rates of only 40 to 50 gal per min. Expectations are that there will be some addition to the anticipated mining costs as a result of this flow of water; precisely how much depends on the long-term deliverability of the water-bearing unit.

At the time of our visit in mid- September, four crosscuts had been driven through the orebody on the 120-m level. A raise bore machine was to be set up in one of these cross- cuts (designated stope 93) and a pilot hole was to begin drilling in about two weeks. That pilot hole would be 200 m long, drilled in ore next to the hanging wall at an angle of about 45 , breaking through on the 320-m level. From there, a reaming head 3 m in diameter would be attached to the drill string and the hole reamed over its entire length at a rate of about 3.5 m per shift. By the end of November, this raise was to have been complete, providing ore for the start-up of the mill, which at the time of our visit was very close to being turned over.

HudBay plans to mine the first slice of ore by lowering an electric-hydraulic longhole rig down the lower half of this raise and drilling a fan of holes two inches in diameter every 1.5 m at right angles to the dip of the deposit. By blasting two or three of these rings at a time into a crosscut on the 320-m level, a single blast from this stope alone would be enough to provide sufficient ore for 24 hrs of mill feed. Each of these stopes contains about 280,000 tons of ore — enough for half a year’s production. Rock mechanics engineer Alan Moss at Golder Associates in Vancouver, B.C., designed the dimensions of the vertical stopes. They are typically 20 m long and 10 m wide.

Two different mining methods are to be used at Namew, depending on the mining width. Longhole raise mining, described above, will be used in 21 primary and secondary stopes between the 120-m level and the 320-m level where mining widths are as high as 27 m. Average widths are 12 m to 14 m. Drift and fill mining will be used in the high-grade, upper portion of the orebody where mining widths average only 2.4 m. In the raise mining area, the bottom 100 m will be mined in alternating stopes and then filled with crushed, cemented limestone as backfill. Then the upper 100 m of the stope will be mined (from the 109-m level to the 120-m level) with ore being mucked from the cemented sandfill in the stope below. Secondary stopes (or pillars) between the primary, mined-out stopes will be mined in the second pass of mining. Overall, extraction should be about 94%, dilution 15%.

Pneumatic wagon drills, manufactured by Atlas Copco, will be used for production drilling in the drift and fill stope above the 120-m level. The mine has purchased two new 2-boom jumbos, equipped with HD 125 drifters, from Boart Canada for development work. HudBay has signed a one- year cost-per-foot contract to supply bits and steel with Kenroc.

In the raise mining stopes, Thyssen Mining & Construction has been contracted to drive the raises. Although HudBay would like to have accuracies of 1% to minimize development work in the draw points, Thyssen has guaranteed accuracy of 2%. Ground conditions are expected to be so good in the strong gneisses in the hangingwall that only occasional ground conditioning will be necessary in the completed raises to accommodate the manned longhole electric-hydraulic drill jumbos (Solo H600R) and charging wagon being manufactured by Tamrock in Finland. HudBay will be purchasing two of these drill rigs (at a cost of about $500,000 each) and one charging wagon (costing $330,000).

Three scoops, equipped with 5-cu- yd buckets, have been purchased from U.S. manufacturer Wagner Equipment. They will be operated by remote controls at the draw points to the raise mining stopes. A smaller scoop may be necessary for mucking in the drift and fill stopes.

Two used Eimco-Jarvis-Clark haulage trucks, with a 27-ton capacity, have been brought in from HudBay’s Trout Lake mine, which has replaced its fleet with larger, 40-tonne units (see separate story, page 33). A third truck, which will probably be purchased new, is needed on the 320-m level, says Senior Mine Engineer Gerald Beauchamp.

Once production begins on a 24-hr basis, 136 people will be employed at the mine/mill complex. Each employee will work a 12-hr shift, four days per week, and will have the option of staying in camp for those four days at company expense. Or he can travel back and forth to Flin Flon every day.

Ore will be trucked to the ore pass on the 320-m level, which feeds a 600-ton storage bin above a new jaw crusher. The ore is crushed to minus 6-inches and stored in a 400-ton bin below the crusher. One 10-ton skip will be loaded in the loading pocket and hoisted to a 1,000-ton storage bin in the headframe on surface.

The ore will be conveyed to the crusher building where two used cone crushers from a concentrator in Whitehorse, Y.T. (a 4 -inch standard and a 5 -inch short head, both from Siemens ag) will crush the ore to minus -inch before going to the mill. The capacity of this part of the milling circuit will depend on the moisture content of the ore and on how easily the material breaks. All components in the crusher building are enclosed with ventilation hoods and blowers to provide a dust-free working environment. A single operator will be needed to run the operation from a control booth in the crusher building. Alternatively, the crushing circuit can be run from the main control room in the mill.

This control system is the showpiece of the mill. Conceptual design of the mill was done by Outokompu from offices in Toronto. But detailed engineering was carried out by Kilborn Engineering with sub-contract work going to a number of companies. A multi-loop Proscon computer system and an Outokompu 30 on-stream analyser (the first of its kind built from the ground up in Canada) will be used by five employees to assist them in running and maintaining the entire milling process. A somewhat similar system is operating in Inco Ltd.’s mill in Thompson, Man., according to Namew Mill Superintendent Gil Labarre. But the Thompson system is an add-on, designed to marry a number of component mill control systems. The system at Namew will provide an endless series of possibilities for mill operators in obtaining the most efficient results from the crushing, grinding, flotation and de- watering circuits. The system features two modes of operation — one for day-to-day operations and one for experimental simulations. “You don’t need a lot of training to learn the system and you can generate numerous reports,” Labarre says. “Probably in the long run an integrated system is cheaper because you’re not marrying a number of units all over the mill.” An added feature for mill operators will be a radio communication system built into their hard hats. Operators on the floor of the mill will be able to stay in contact with the operator in the control room. The radio operates on two channels — one for operations personnel and one for maintenance.

One of the interesting aspects of this mill is the thought that has gone into the design, starting from the plant layout right on up to the computer control system. The main control room separates the noisy grinding circuits on one side from the relatively quiet flotation and filtering circuits on the other. A clear view of each circuit is provided from the second- floor room and a splended view of the lake through the north wall window lends an added touch. Down on the mill floor, even the sumps are organized to drain from each of the rougher, scavenger and de-watering circuits. And all pumps are arranged along a central aisle, easily accessible by forklift and a 15-ton overhead crane manufactured by Kone.

Interesting new pieces of equipment in the mill include two radioactive belt scales — one installed before the cone crushers and one before the rod mills. These units, manufactured by Berthold of West Germany, are small enough so that they do not occupy too much space, and their performance is not affected if installed on an inclined conveyor belt. At the dewatering end of the circuit are two Enviro-clear thickeners — deep, vertical thickeners, which again do not take up excessive space in the mill. These thickeners are also used in HudBay’s zinc and copper mills in Snow Lake and Flin Flon.

Concentrates from the Namew mill are expected to grade about 17% nickel. Although the company’s metallurgical projections are based on bench-scale tests on drill core, Outokompu’s Niitti is confident the mill will perform better than what is anticipated from those tests. Concentrates will be trucked to a load-out facility at Atik, Man., where 60% will go north to Thompson and 40% will go south and then west to Fort Saskatchewan.

Tailings from the flotation circuit in the mill will be pumped to the tailings area directly south of the mill. Dams around the relatively flat area are high enough to contain two years of tailings. They will be raised to accommodate more tailings as mining progresses. Overflow will go into a small clarifier pond, then into Namew Lake.

Waste rock from underground development headings is being crushed for building surface roads.