What a gem!

Challenges abound at the Victor diamond project. That, and the people drew general manager Peter Mah to the wilds of Northern Ontario in November 2007. He told CMJ during a brief December 2008 interview, “I always said I’d only leave gold mining for diamonds.” Now he is overseeing Ontario’s first diamond mine, a $1-billion undertaking, with all its challenges, firsts and incomparable people.

One of the challenges Mah particularly appreciates is the opportunity to play a part in shaping the fledgling Canadian diamond industry for decades to come. “Victor is the first major industrial development on the west side of James Bay,” he said. “How we shape our business structure is key to the region and local community.”

The Victor kimberlite is the first De Beers discovery outside South Africa to become a mine. Besides Victor, there are 15 other kimberlites under the De Beers umbrella in the James Bay Lowlands. “The long-term potential of the area is great,” Mah added. “But diamond projects need a long lead time. We are gaining geological and exploration knowledge at Victor which remains unique, with innovative new thinking necessary to outline reserves.” He noted the bulk sampling plant as one means of expanding exploration success.

Also a first at Victor, is the high level of collaboration with First Nations. Their importance is seen in the use of their traditional environmental knowledge, the display of their cultural icons throughout the accommodation complex, and the training provided by De Beers so that they have become valuable employees. First Nations people make up 43% of all workers at the site and 60% of the operators and employees in the mining department.

Victor has recently passed its ISO 14001 environmental audit, and official recognition is expected in the second quarter of 2009. The project also enjoyed the same designation during exploration and construction.

Victor mine 170 million and 37 years in the making

The Victor diamond mine was 37 years in the making, not an uncommon length of time for projects first explored in the 1960s, and less than a blink in the geological timeline that created the world’s highest-quality diamonds 170 million years ago.

The definitive story of De Beers’ success in Canada has been written recently by Richard Molyneux, former president and CEO of De Beers Canada. His book, Catching a Dream, covers the company’s efforts across this vast land.

De Beers came to Canada in 1961, and that year collected the first kimberlitic indicator minerals from the Attawapiskat River in the James Bay Lowlands. The follow-up program two years later unearthed a single diamond from the Lawashi River, a tributary to the Attawapiskat. Continued exploration failed to uncover any further diamonds, and as the diamond rush heated up in other parts of Canada, the company left its claims in northern Ontario untouched for the next 20 years.

When interest in the diamond potential of the James Bay Lowlands was rekindled, De Beers opened an exploration office in Thunder Bay, Ont., and four years later, in 1987, established a field camp on the banks of the Attawapiskat River. In August that year, while fishing in the river, young geologist Brad Wood spotted the first kimberlite boulder on the banks. That lead to setting De Beers’ first claim post for what would become the Victor diamond mine.

Finding the source of a kimberlitic boulder in the heavily glaciated terrain of northern Ontario is not easy. Airborne and then ground magnetic surveys were conducted, and 25 anomalies worthy of further investigation were outlined. In 1988 the first ice road was built to bring drilling equipment into the Victor site.

Excitement mounted during the 1988-89 winter drill program. Nine kimberlite pipes were confirmed. The next year another seven were drilled. Although the main Victor pipe measuring 16 hectares on surface is large by Canadian standards, the other kimberlites appeared to be very small. Focus drifted away from northern Ontario to other activities in Saskatchewan and the Northwest Territories.DeBeers returned to its Victor claims in 1995 after earlier microdiamond samples were reinterpreted. More holes were drilled and three additional kimberlites discovered in 1997.

Now the company faced a dilemma. If the Victor project became a producing mine, the grade was too low to sustain it. The redeeming feature was the superior quality of the individual diamonds — higher than any other diamond mine in the world. The beautiful Victor stones are worth US$400 per carat, compared to average global rough diamond production worth US$80 per carat.

One look at the diamonds from the Victor project, so the story goes, was enough for the board of De Beers to give the go-ahead for development. In 1998 the project moved into the full evaluation process and pre-feasibility study. The De Beers board gave the green light for construction at the Victor project in 2005. That year the project received its operating permit, and key impact benefit agreements were signed. Now work began toward a 2008 start-up date with renewed commitment.

The difficulties in finding a diamond mine in the world’s second largest wetland are overshadowed only by the logistical challenge of moving equipment, accommodations and people into the site. For three years construction materials were marshalled at the Canadian National railyard at Concord, Ont. Supplies were then sent by rail to Cochrane, and along a branch line to Moosonee.

Moving freight from Moosonee to the Victor site took place over 373 km of ice road during February and March. To Attawapiskat the first 270 km of the ice road follows the western shore of James Bay, then it turns due west to the mine site. Barges were used early in the project to move some materials from Moosonee to Attawapiskat, and they are still used today in the summer. However, it is the ice road that remains the main resupply link fuel, tires and heavy equipment.

In 2006, the management team reviewed its options to shorten the construction schedule. The solution was an freight program during the spring and early summer. The tiny airstrip at the mine site became a beehive of activity as steel and other components for the dense media separation (DMS) plant were delivered. With the critical parts on hand, the construction team changed the build sequence and immediately erected the DMS plant. In a first for De Beers, the main building was erected around the DMS plant after its completion.

The original startup date of October 2008 was moved several times during the construction phase, with Victor tightening up to an eventual start for operations on January 20, 2008. Full production was achieved just six months later on July 26, 2008–which was, ironically, the same day the mine celebrated its official opening with community members, employees and senior De Beers executives from across the globe.

Astoundingly, during the construction phase of the project, workers put in over 4 million person-hours without a lost time accident. That kind of safety is possible only with the utmost commitment from the top to the bottom of the organization, including contractors.

Partnership of equals

De Beers practises what it calls the “triple bottom line” — economic, social and environmental sustainability. The company knows that no modern mining project can succeed without the support of the community directly affected by its development.

In the case of the Victor mine, there are several First Nations communities nearby. The mine is located on the traditional lands of the Attawapiskat First Nation, with the community approximately 90 km due east on the coast of James Bay. Also in the local area are the Kashechewan, Fort Albany and Moose Cree First Nations. Their members have been consulted since the early stages of exploration, and a number of working agreements were put in place to match the various stages of development. First, many c
ommunity members were working with the exploration team, then were asked to help prepare the environmental assessment, and their traditional environmental knowledge (TEK) has been indispensable. There is a joint environmental management committee with the community and all permits are prepared jointly to ensure the best interests of both parties.

The numerous joint ventures with the First Nations cover trucking, air transport, security, catering and more. Together the agreements are worth over $110 million, and the participants are gaining skills that can be used in other industries as well as mining.

Fulfilling its commitment to social sustainability, De Beers not only signed IBAs with the First Nations, but also established several training and educational initiatives. De Beers contributed $800,000 to the construction of a training centre in Attawapiskat. The federal government recently added $7.87 million to this effort. Caterpillar established a training program for heavy equipment operators with Northern College in Timair mins for six apprentices, all of whom were hired by Toromont, the mining fleet supplier at Victor. Another 20 operators completed the program this year and found employment with De Beers.

To date, more than $165 million has been spent with Aboriginal joint venture partners on the project, which the local First Nation communities made a priority regarding business opportunities.

Fireworks captured in icy stones

The diamonds deposited in Northern Ontario 170 million years ago are among the most beautiful in the world. The rough looks polished, clear and fiery. The finished diamonds are prized for their clarity, colour and superb cut.

The complex geology of the Victor North pipe has challenged the understanding of earth scientists since the first diamond was discovered 35 years ago. Geologists who have studied and written about the Victor kimberlites note the presence of 19 separate kimberlites in the area. The Victor Kimberlite consists of two adjacent and discrete pipes dipping approximately 70 in an Ordovician to Silurian sedimentary succession that unconformably overlies the Precambrian granitoid basement at about 275 m below the surface. Further, the pipes are overlain with about 10 to 30 m of glacial overburden (van Straaten et al., 2007).

The authors of the Geological Survey of Canada’s Current Research Report 2005-C1 put the Victor geology in perspective, drawing in part on earlier reports. “The pipes are characterized by two textural types of kimberlite formed at different times. The northwest part of Victor North resembles hypabyssal kimberlite but comprises numerous lapilli tuff horizons and sedimentary rock breccias and is associated with an early phase of emplacement.

The sedimentary breccias are composed of now-eroded stratigraphic units and are also found along parts of the pipe margin. The southern part of Victor North, and Victor South, which are referred to as the ‘pyroclastic kimberlites’, are composed mainly of pyroclastic, lapilli-bearing olivine tuff deposited during a later eruption event that excavated a second crater crosscutting the original crater” (Bellefleur et al., 2005).

As insights into the placement of the Victor kimberlite were made, geologists were able to delineate the various types of material and identify the central part of the north pipe, referred to as Victor Main, as having the best grade. The resource there is 11 million tonnes with a grade of 32 carats per hundred tonnes (cpht). To be mined beginning in 2011, Victor South has a resource of 16 million tonnes with an average grade of 17 cpht. The northwest portion of the north pipe, known as the Victor North hypabyssal kimberlite, is virtually barren with a grade of less than 1 cpht.

Victor mining plan

Before mining the Victor kimberlite could begin, De Beers removed 17.4 million tonnes of silt, sand and clay plus 1.2 million m3 of muskeg. The overburden and muskeg were stockpiled. The material will be preserved for eventual reclamation, and researchers from Laurentian University have already been testing revegetation methods.

The wet nature of the James Bay Lowlands also necessitated extensive dewatering of the area before mining. A ring of seven 50-cm-diameter dewatering wells has been drilled around the pit area, and an average of 85,000 m3/day is discharged to the Attawapiskat River, 6 km away. The groundwater is slightly saline but that will not affect the quality of the river water.

A pit sump has also been established. For the first six years of operation the pit water will be non-saline, and it will be pumped to a settling pond before discharge into a linear fen system. From the fen the water will eventually flow to the Nayshkootayaow River. After year six, the pit water will become saline. It will be pumped to a lined settling pond before discharge along with the saline groundwater into the Attawapiskat River.

On the brilliant, wintery December day CMJ visited the pit, I met mining manager Rory Greyvensteyn and technical services manager Brad Wood (who discovered the first kimberlite boulder in the Attawapiskat River). They oversee day-to-day operations when they are on site. From a windy overlook, we discussed conventional pit operations.

The pit is only about 1,000 metres in diameter, which makes it small by many standards, and at the time of my visit was 30-metres deep. The first phase of mining is recovering high-grade kimberlite from the central part of the Victor North kimberlite. The next phase will move to the northwest portion of the same kimberlite in 2011.

The Victor mine has what Wood calls a “dynamic ore reserve”, and that leads to lots of sampling. Not all the kimberlite is diamond-bearing, and the part that is cannot be differentiated visually. Nonetheless, diamond grades and recovery have been close to the forecast, he said. The grade is 40 cpht, although as mining goes deeper that will drop to 30 cpht. The daily mining rate is approximately 14,000 tonnes, 7,000 tonnes of diamond-bearing kimberlite for the plant and the balance is waste.

A single Sandvik D25KS drill is available to punch 10-metre holes for blasting. Once the holes are drilled, technicians from Orica perform the priming, loading, tying and shooting of the blast under contract. Orica has built an emulsion plant on site. A blast occurs every three to four days at which time between 35,000 and 40,000 tonnes are broken.

Toromont provided all the Caterpillar equipment for the pit. There are a Hex Cat 385 and a 345 shovel for removing overburden and muskeg, and the shovels load the four 733 off-road trucks and two 740 ejector-bed trucks. Two Cat front-end loaders, a 992 and 998, place kimberlite in three, 100-t 777 haul trucks for transport to the primary crusher or various stockpiles. There is a fourth 777 used to transport coarse processed kimberlite to its stockpile.

Service equipment was also supplied by Toromont. These units included low-ground-pressure dozers (two D6, two D9 and one D5), a 16G grader and a 350 shovel fitted with a backup blasthole drill boom.

The planned annual mining rate is 2.5 million tonnes.

Diamonds out of reach

Separating all of the Victor diamonds from the kimberlite is highly automated. The reasons are twofold. One, missing even one stone of such high value can significantly hurt profitability. And two, the employees’ security is protected because they cannot be intimidated into acts of theft if they never handle the diamonds.

Run-of-mine ore passes though an MMD primary crusher, and then is washed and screened into three sizes. The oversize fraction (+28 mm) is sent to a Nordberg cone crusher to liberate the diamonds and then sent to the FFE scrubbers with rubber liners. The -28 to +6 mm fraction is sent to the coarse dense medium separation (DMS) feed bin. The -6 to +1.4 mm fraction is conveyed to the fine DMS feed bin.

Material smaller than 1.4 mm is wa
ste and referred to as “processed kimberlite” (PK). It is pumped to the degrit section where it is cycloned, and the overflow (- 300 micron) is gravity fed to Outokumpu thickeners. Then the fine processed kimberlite (FPK) is pumped to storage. The overflow water from the thickeners is gravity fed to the process water tank to be reused. The cyclone underflow (+300 micron) is dewatered and will be stored in a processed kimberlite containment (PKC) area.

The diamond-bearing material is transported to the DMS circuit by a pair of Strongco high-angle conveyors, the use of which helps keep the plant footprint as small as possible.

In the DMS circuit, fitted with Multotec cyclones and densifiers, screened ore is mixed with slurried ferrosilicon power (FeSi) to maintain an operating density of 2.65. Closely controlling the specific gravity allows denser material, particularly diamonds, to report to the cyclone underflow. Both the coarse and fine DMS cyclone sinks (underflow) are sent to the diamond recovery circuit for magnetic separation, x-ray identification and laser sorting.

The coarse DMS cyclone overflow measuring +6 mm is send to the Polysius high-pressure roll crusher (HPRC) section to be recrushed, screened and washed to liberate small diamonds remaining in the kimberlite. The fine DMS overflow (-6 to +1.5 mm) is conveyed to the coarse PK bin. The FeSi powder is recovered in the magnetic separators and reused. It is a non-toxic, non-reactive material that poses no threat to the environment, unlike chemicals used to recover gold or base metals.

The DMS cyclone sinks are dried and passed through Raven x-ray sorting machines. Diamonds shine when irradiated with x-rays, and that allows subsequent removal from the crushed kimberlite. X-rays in the Victor diamond plant are generated by x-ray tubes that are enclosed to prevent radiation exposure to employees.

A diamond-rich concentrate is produced by the x-ray sorters. It is then sent in batches to a single Raven particle laser sorting machine. The diamonds are collected in a glove-box arrangement where they are sized, counted and sealed in secure containers for shipment.

“Diamond recovery is a very finicky process,” added Ian Holl, process and maintenance manager. Process efficiency is paramount but only attained in a very small range of densities. Consequently, the entire kimberlite processing plant is highly automated as evidenced by the control room. The software of choice for this task is PCS 7.

Fortunately, the kimberlite at the Victor project is non-acid generating, a characteristic that simplifies management of the PKC area. Both the course and fine PK is thickened. The fine PK will be stored initially in the former central gravel quarry. The coarse PK is being stored in a stockpile. Design of the permanent PKC area has not been finalized.

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Logistics statistics

The scale and complexity of Victor’s logistics is illustrated by these statistics for the period 2005 to 2008.

• 3,411 truckloads transporting 187,000 tonnes of general goods

• 891 fuel trucks transporting 32,800,000 litres of diesel

• 1,004 passenger flights transporting 36,765 passengers

• 488 light freight flights transporting 6,399,950 pounds

• 950 heavy freight flights transporting 13,528,124 pounds

• 18 barging operations transporting 30,600 tonnes

• 1,600 rail cars transporting 61,000 of freight (including 4,000 tonnes of piping,

• 1000 tonnes of conveyor belting and 268 tonnes of tires) – from Catching a Dream

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Bulk Sampling Plant

The original 10-t/h bulk sampling plant is still operational at Victor. Its continued use allows for the testing of bulk samples from any of the other 15 kimberlites on De Beers’ holdings. If the Victor project is to remain in long-term operation, a new, economic ore source will have to be developed, and that takes time. The bulk sampling plant allows exploration and testing to proceed without interrupting the kimberlite processing plant. And if the samples contain diamonds, they can be recovered in the existing DMS circuit.

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De Beers Kimberlite Discoveries In Canada

Mid-1960s Ile Bizard, Que.

Mid-1970s Somerset Island, NWT

1982 Kirkland Lake & New Liskeard, Ont.

1988 Attawapiskat, Ont.

1988 Sturgeon Lake, Sask.

1990 Mountain Lake, Alta.

1992 Hardy Lake, NWT

1994 Upper Carp Lake & Hardy Lake, NWT

1995 Upper Carp Lake & Rockinghorse Lake, NWT

1996 Rockinghorse Lake, NWT

1977 Kennedy Lake & Upper Carp Lake, NWT

1998 Victoria Island, Nunavut -from Catching a Dream

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