Canadian Mining Journal

Feature

Getting There

Picture a weight-lifter and a gymnast, strapped together to form a gangling, three-legged runner. This is Inco Ltd.'s Voisey's Bay nickel project--the open pit mine and concentrator i...


Picture a weight-lifter and a gymnast, strapped together to form a gangling, three-legged runner. This is Inco Ltd.’s Voisey’s Bay nickel project–the open pit mine and concentrator in Labrador, and the tiny hydromet demonstration plant in Newfoundland–as they all race to start up before the Labrador Sea freezes over this winter.

What’s the rush? In signing the Voisey’s Bay agreement with the province, Inco guaranteed that it would ship no concentrate from the mine to its metallurgical facilities in Ontario and Manitoba until its demonstration plant in Argentia, Nfld., was ready to test the concentrate. The company has further promised the Labrador Inuit Association that the first shipment will not be through ice, and there will be no shipping during two six-week periods–early winter and spring.

Given those constraints, Inco’s wholly-owned operating company based in St. John’s, Voisey’s Bay Nickel Co. (VBNC), needs to have enough nickel concentrate ready to ship from Labrador by November, or it won’t be able to ship its first concentrate out until next summer. With the price of nickel near record highs (US$5.50-6.50/lb), after nine years the Voisey’s Bay project is anxious to start paying its way.

In many ways, this is an ordinary mine using conventional technology. (Details can be found in an article we published last year: “Made in Canada”, CMJ April 2004). Its 400 employees will mine and process 6,000 tonnes/day of Ni-Cu sulphide ore, annually producing 110 million lb of nickel, up to 85 million lb of copper and 5 million lb of cobalt in concentrate.

Since prefeasibility stage, the company has worked hand-in-hand with EPCM contractors SNC Lavalin/BAE-Newplan in Labrador, and SGEHatch at Argentia. Phase 1, comprising the open pit mine, mill and demo plant plus transport and handling facilities, has cost the company Cdn$1.2 billion (US$920 million) in capital, over a 35-month construction period.

Management sees the Voisey’s Bay project as a peer of other remote northern mines–Raglan, Ekati and Diavik–with similar wages and permanent camp. It’s a fly-in operation in a remote location with challenging winter weather.

Some technical aspects make it more interesting. The mill will be making three separate concentrate products. The demonstration plant in Argentia will discover if pressure oxidation leaching can be used commercially on nickel sulphide concentrates. It will be replaced by a Cdn$800-million full-scale commercial plant in 2012 (Phase 2).

The social and political context is even more interesting. “We have had to think outside the box to structure relationships and partnerships with stakeholders in Labrador and with the university,” says Bob Carter, VBNC’s manager of public affairs. The company concluded confidential impact benefit agreements with both the Labrador Inuit Association (LIA) and the Innu Nation before it signed the Voisey’s Bay Agreement with the province in 2002. Among other things, the agreements give first opportunity to local and aboriginal employees and supply companies. The Inco Innovation Centre at Memorial University in St. John’s officially opened Sept. 20, partially funded by Inco, which chipped in $20 million toward capital and operating expenses.

Mine, mill and transportation

The Voisey’s Bay orebodies are rich. Proven and probable reserves (mainly the Ovoid deposit), are 30 million tonnes grading 2.85% Ni, 1.68% Cu and 0.14% Co–richer in all three base metals than Inco’s reserves in Ontario and Manitoba, although the Labrador ore contains virtually no precious metals.

The pit will have an average waste:ore ratio of 1.4:1. There will be a total of 35 benches, each 7-m high, taken in a single pass. The main shovel for overburden and ore is a Hitachi 1900. Caterpillar provided the bulk of the mining equipment, including a 992 loader for backup, three 777 haul trucks, three D9 dozers, a 385 backhoe and auxiliary and support equipment. Reedrill SK drills are used for production. To minimize the amount of oxidation of sulphide minerals, there will be only about two weeks of broken ore in inventory.

The pit will be depleted in 2019, at which time the deeper deposits (Eastern Deeps and Reid Brook) may be exploited by underground mining (Phase 3).

The flowsheet for the concentrator uses conventional flotation technology, but the complication is in the number of products. Concentrator manager Joe Holmes points out that there will be two distinct periods for the mill.

At first, the plant will produce three types of concentrate: high-grade nickel (24% Ni and *0.5% Cu) for the Thompson smelter; middlings concentrate (14-16% Ni and 4-6% Cu) for Inco’s Copper Cliff, Ont., smelter; and high-grade copper concentrate (30% Cu and *0.5% Ni) for custom smelters. Keeping the copper content low enough in the high-grade nickel concentrate to be acceptable at Thompson is a challenge.

Phase 2 begins when the commercial processing plant is in operation in the province in 2012. At that time the nickel concentrates will be combined (20% Ni and 4% Cu), while the high-grade copper will continue to go to custom smelters.

An ongoing challenge will be to maximize pyrrhotite rejection.

An integrated team from SNC, VBNC operations group, contractors and outside experts is handling the mill commissioning, which began this August, running waste rock through the crusher and mills, replaced by low-grade ore in mid-September. “The kinds of problems we are getting are frustrating,” said Holmes, “but we should have no problems meeting our deadlines. We were fairly reasonably conservative in our start-up plan.”

Says Labrador site general manager Bob Cooper: “The schedule demands that we start up operations while we are still finishing the construction, which means that communication and co-ordination are critical. Commissioning should be complete by the end of October. Then we estimate ramping up to capacity over a six-month period.”

At the same time, the concentrate storage and loading facilities at the shipping port are being commissioned using sand, and maintenance personnel are being trained. “They have done a lot of computer simulations, but using the real equipment is different,” says Cooper.

All fixed equipment at the mill and minesite is being maintained by a contractor–a partnership between Iskueteu and ABB–which provides its own planners and supervisors. This is a performance-based contract, meaning that the better the site performs, the more money the contractor makes.

Ultimately almost everything needed at the Labrador operations other than people will be shipped by the MV Umiak I, a 30,000-tonne-payload combination ice-breaker/bulk-carrier being purpose-built in Japan for shipping contractor FedNav. Until April 2006, FedNav’s MV Arctic, the same ship that supplies Raglan, will serve Voisey’s Bay.

The shipping wharf is 11 km north of the mine at Edward’s Cove on Anaktalak Bay, 70 km east of the fiord’s mouth to the Labrador Sea. The trip from the wharf to Quebec City takes four to five days by ship, whereas the route from the wharf to Argentia will take three days. From Quebec the nickel concentrate will be sent by rail to Sudbury and by rail and truck to Thompson.

The current schedule will see 12 loads of up to 30,000 tonnes of nickel concentrate go to Quebec per year, eight in the summer and four in the winter. There will be three or four shipments per year of copper concentrate totaling 120,000 tonnes, all in the open water season. Part of the shipping agreement with the LIA states that there will be no shipping during two six-week periods–the beginning of winter when ice is forming, and in the spring because Inuit are using the ice intensely, the seals are whelping and ice is unlikely to refreeze.

The air contractor is Innu Mi
kun Airlines
, an Innu partnership with Provincial Airlines. It operates a Dash 8 flight every weekday from Goose Bay to the airstrip next to the mine camp. As well, there are three Twin Otter flights per week, from Goose Bay via coastal communities to the site.

Argentia plant

The 8,000-kg/day hydrometallurgy demonstration plant was built in Argentia, Nfld., on an 18-ha site, formerly part of the US Naval and Air Base. The 105-m x 42-m main building is 10 m tall, with a 13-m tall bay housing the grinding and autoclave.

“The objectives of the plant are to demonstrate the process using commercial equipment on a continuous basis; to generate design information for a full-scale plant; and to train commercial plant operators,” says operations manager Don Stevens. “The mini-plant [at Inco Technical Services Ltd. in Mississauga, Ont.] ran nine campaigns, the longest lasting 10 days. This plant will run 24/7.”

The -14 mesh, 2% Ni concentrate from Voisey’s Bay will arrive in 12-tonne bags, a mixture of high-grade nickel and middlings. Concentrate will go through a roll crusher followed by two stages of wet grinding in a ball mill and two tower mills, to reduce it to -10 microns.

The heart of the process is the pressure leach circuit (autoclave) where the metals are leached into solution by acid under pressure. Limestone neutralizes the acid, and counter-current decantation removes the waste residue from the leached slurry. A two-step process using hydrated lime and oxygen removes iron from the metal solution, which is then purified using solvent extraction. The final stage is electrowinning, first for copper, then for cobalt, and finally for nickel. In the case of nickel, there are 50 1-m2 sheets in each of three tanks. The sheets take 7-10 days to plate, and are 99.9% pure nickel.

Stevens describes the process as “kind of elegant”. Each tonne of concentrate results in a tonne of fairly benign residue, which is comprised of waste rock, hematite (Fe2O3), gypsum (CaSO4) and elemental sulphur. All residue will be collected and stored in double-lined residue ponds for the whole demonstration period.

Novel features include:

* a new application of hydrometallurgical processing in which pressure leaching of nickel sulphide concentrates is followed by direct electrowinning of the nickel;

* a patented use of chlorine in solution (the chlorine gas is recovered and recycled);

* the sequential removal of impurities using solvent extraction and the recovery of copper, cobalt and nickel by electrowinning.

An impressive online process control system not only controls the functioning of the equipment but also is a repository for all data including that from the lab.

First concentrate was introduced into the plant on Oct. 20. The demonstration plant will operate to the end of 2007, at which time the company will decide whether to stay with hydromet technology or build a conventional refinery. The province will review Inco’s report and, by the end of 2008 a final decision will be made on the processing technology. Construction of the commercial plant will begin in early 2009, and it should begin operation in early 2012.

Keeping it clean

In many ways this is a ground-breaking mine development. Voisey’s Bay was one of the first major mining projects in Canada to be subject to the Canadian Environmental Assessment Act. It was also the first project to have a multi-party memorandum of understanding in which the Innu and the Inuit sat with Canada and Newfoundland in a harmonized environmental review of the project. Voisey’s Bay is Inco’s first mine working toward incorporating ISO 14001 international environmental management system standards. The project has stayed well within its environmental limits to date.

VBNC’s manager of environment, health & safety, Earl Dwyer, described the practices in Labrador.

Tailings from the concentrator will be pumped 9 km east to a 140-ha tailings impoundment area made from Headwater Pond, 30 m deep, with 12-m-high dams at head and mouth. In September 2004, about 1,500 fish were relocated to a remote pond, and remain healthy. The pit will deliver 15 million m3 of tailings and waste rock (containing 0.2% sulphur) to the impoundment over its life. This will be deposited beneath 4 m of water to prevent oxidation. Water from the impoundment will be reused in the concentrator.

PSI designed the 20-cm-diam, graduated, high-pressure tailings line, which is continuously welded to prevent leaks. There is a leak detection system on the tailings line. All lines (water and tailings) have been heat-traced to prevent freezing.

Settling ponds are lined with HDPE. All water from the mine and process plant as well as any water that may have been in contact with ore or waste rock is collected. Water that is not returned to the mill is treated in a lime-based reactor-clarifier system. The cleaned water is pumped to Edward’s Cove, where it is discharged through a 40-m-deep diffuser.

Dust is one of the main areas of concern and efforts are being made to control its emissions. The primary crusher next to the pit is in an enclosed area, and the crushed ore conveyor is covered. The final concentrate with 8-9% moisture, will be trucked to the concentrate storage building at Edward’s Cove, which is equipped with a dust collection and monitoring system. All parts of the conveyance system from the building to the ship’s hull are covered. An “elephant trunk” is used to place the mouth of the chute near the surface of the concentrate in the ship’s hull, to minimize the drop.

Timing brought forward

When Inco purchased the Voisey’s Bay property in 1996 for Cdn$4.3 billion, the company was anxious to develop the resource. However, contentious negotiations with the province and the requirement to sign impact benefit agreements with the aboriginal groups resulted in a protracted gestation period.

When the company gave the project the final go-ahead in March 2003, first ore shipment was expected in mid-2006. However, calculated risks taken during site preparation allowed the Phase 1 schedule to be improved by more than eight months, with costs coming in on budget. Joe Shirley, the project director of both the mine and mill and the demo plant projects explains how the work was sped up.

“We advanced the earth work and concrete work in Labrador in 2003 by making assumptions about the final concentrator design, the size and the requirements of the buildings, before the engineering was complete. That allowed us to pour the foundations in 2003. We were able to start construction in April rather than July 2004. Those few months we gained in the beginning had a big spin-off later on. By shortening the construction time we have reduced our holding costs for contractors.

“Logistics also worked out well. We shipped in 112,000 tonnes of material, supplies and equipment from 2003 to 2005 and in many cases were able to get the contractors to deliver early because we stayed on top of them.”

With the mine ahead of schedule, attention shifted to the demonstration plant at Argentia. “The prefeasibility and feasibility studies were being done in late 2003 at the same time the mini-pilot plant was doing its test work, so we had to make some assumptions,” says Shirley. Bob Kelly, construction manager for the demonstration plant, noted: “Hatch determined that the way to shorten the construction time and still maximize work by local suppliers was to maximize modular construction, and then hook up the mechanics once the modules were delivered.” The modules, designed by SGE Hatch, were each about 3.6 m wide x 3.6 m tall x 12 m long, designed to fit on a transport trailer. Some elements of the plant were “stick-built” such as the crushing and grinding section.

Site preparation began on May 3, 2004, and that year was spent building infrastructure – the guardhouse, effluent lines and shell of the building and the r
esidue ponds. Module construction began the end of 2004 and the modules have been shipped to the site since this May. Much of the work was done by a local fabricator Metal World in a facility just a kilometre from the plant site. All parts of the plant were built in Newfoundland except the eight-module autoclave (from Zeton of Burlington, Ont.) and the solvent extraction components (built by Lyntek of Denver, Colo., and assembled locally).

Module building and assembly has allowed local firms to expand their capabilities. For example, the various tanks were made by local firms more accustomed to building boats than industrial equipment. This experience will equip them to provide ongoing maintenance to the components, and to understand the needs of the commercial plant when it is built.

Local workforce

VBNC is committed to giving preference to the communities close to its operations, especially Innu and Inuit, for employment as well as purchasing supplies and services. “During construction, more than 85% of the workforce building the mine and concentrator were from Newfoundland and Labrador,” says managing director Phil du Toit. “More than 80% of the capital spent on contracts went to Newfoundland- and Labrador-based companies; about 50% of the total went to aboriginal-based partnerships.

“We’ve even exceeded the expectations on operations: more than 95% of employees at the mine and concentrator are from the province; 80% are residents of Labrador [including all senior management], and 50% are from the aboriginal groups. About 85% by value of our re-supplies–consumables, reagents, whatever–will be supplied by Aboriginal companies.”

Finding the right skills in the country, let alone the province and region, was a challenge, particularly in the fields of skilled trades and management. Some employees had to be brought in. While he’s working on toning down his South African accent, du Toit counts himself as a Newfoundlander.

There are financial incentives for mine and port employees to live in Labrador. Labradorians receive a $5,500 annual northern living allowance, and their travel costs to and from work are completely covered from nine pick-up points in Labrador. For employees living outside Labrador, VBNC subsidizes 80% of the travel cost to Goose Bay, but that has created displeasure among the townspeople already suffering from downsizing at the Canadian Forces Base in Goose Bay.

“The key for us will be to retain the right skills,” says du Toit. “There’s a demand for them, specifically from the oil sands projects. We have to put extra effort into developing and training the people from Labrador, because we’re in a better position to retain their skills, as a long-term strategy.”

In Labrador, VBNC used the construction period as an opportunity to provide training to likely local employees, and to find out who would make the best permanent employees. “We have hired a lot of people who were on the construction crews for the mine,” says Cooper. “On the maintenance side, we have hired lots of the people who built the plant.”

The workforce at Voisey’s Bay will total 400 plus contractors, with 225 of the former on site at any one time. The rotation for operations crews will be two weeks in/two weeks out; superintendents will work nine days in/five days out; and senior management will work Monday to Friday at the site, and be home in Goose Bay for weekends. There will continue to be contractors on site including TSI for site services.

The Voisey’s Bay project has had considerable success in minimizing injuries during construction, maintaining a rate of 0.9 disabling injuries per 200,000 hours worked since 2002. The frequency rate during 2004 was 0.4. This compares favourably with an average rate of 4.5 for construction in Newfoundland, and 1.2 for the mining industry in Ontario (both figures in 2003). This good work was marred by the death of a contract employee in early January this year, who was struck by a snow-clearing machine.

Unlike the Voisey’s Bay site, the plant in Argentia is not remote, being a 130-km drive from St. John’s. However, the nearby town of Placentia and environs has a fairly small population. VBNC has had to be proactive in developing its own operations workforce of 150 employees including contractors.

Potential employees from the province were trained at Inco’s mini-plant in Mississauga. Twenty people took an introductory course for process operators in Placentia, set up by the College of the North Atlantic. To date, 55% of the Argentia operations workforce are from the Placentia area. More local residents need to be trained for specific jobs; VBNC has awarded 20 scholarships with the same college for engineering and lab sciences programs.

From construction start in May 2004 to the end of September 2005, the Argentia site has recorded a perfect safety record: 230,000 hours of work without any lost-time accidents.

Aboriginal careers

The success of the Voisey’s Bay mine will depend heavily on the Labrador Inuit and Innu. The impact benefit agreements (IBAs) signed with the LIA and the Innu Nation require certain levels of employment. In any case, people from Labrador are more likely to stay over the long-term.

About 1,000 Aboriginal individuals have worked on the construction phase of the project. This is a large number considering that only 7,300 people are covered by the IBAs–5,000 LIA and 2,300 Innu Nation members–almost half of whom are under 25. As of early October, there were 155 LIA members and 55 Innu employed in permanent operations.

Isabella Pain, superintendent of Aboriginal affairs, sees the main advantages of employment at the mine as permanent jobs close to home, offering unprecedented economic stability. The two weeks in/two out schedule allows for lots of time with family and for traditional activities. There are also opportunities for ongoing education. “These are not hollow words,” says Aboriginal co-ordinator Tom Paddon. “At the graduation from a program that we put together in Natuashish, some people told us this was the first time in their lives that they had ever achieved anything.”

“The key to finding the right employees [for the mill] was a good selection program,” says concentrator manager Joe Holmes. “Our training superintendent Bob Marshall put together our training program. There was a two-week pre-selection classroom program, in which we observed the candidates’ attitude, interest and academic abilities. This allowed us to narrow the field. Candidates were then sent for one week of training at Inco’s Clarabelle mill [near Sudbury]. From gauging their interest level we were able to make our hires. These people were given a very intensive three- to four-month training program, both field- and computer-based, and the 14 aboriginal operators are doing very well.

“Another key was that the work has been designed so the new trainees are likely to be successful. We have a central control room run by very experienced operators, meaning that the guys on the floor can get by with less experience. Eventually we will give them more responsibility. This is a different approach to training, and so far we have had very positive signs.”

Good prospects

By Lesley Rose

Junior explorers are nipping at Inco’s heels near Voisey’s Bay. The most exciting region is directly south of the mine, where Inco just staked 6,884 new claims and is planning extensive drilling. The new acquisitions in the Garland Lake region completely surround existing claims held by Freeport Resources Inc. (Notakwanon property) and Cornerstone Capital Resources Inc. (Garland Lake property).

Through audio-magnetotelluric (AMT) surveys, Inco has tracked deep conductive bodies suggesting the presence of troctolite. One of these surveys conducted in 2000 mistakenly covered ground held by Freeport, which was only given the data this past spring. An independent assessment of the geophysical data
concluded that there is a 150-m-thick, V-shaped conductive body 500 m below surface, which will be investigated with drilling and EM surveys.

To the west, Celtic Minerals Ltd. holds 309 claims totaling 190 km2. An AMT survey has been commissioned by Celtic on a 13-km-diameter gravity anomaly coincident with deep magnetic anomalies. This property is held on a 50%-50% basis with Jilbey Gold Exploration Ltd., recently acquired by High River Gold Mines Ltd.

Cornerstone now has a 570-km2 total land position, second only to Inco, which holds 2,279 km2 after the recent staking blitz.

Lesley Rose (rose@geology.utoronto.ca) is a PhD student in Geology at the University of Toronto.


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