Val d’Or, Que. — The proliferation of headframes along Hwy. 117 between here and Rouyn-Noranda attests to the high degree of underground exploration and development being carried out by
Agnico’s flagship mine, LaRonde, has been in production since 1986 and a few years ago underwent an increase in daily capacity to 7,250 from 1,500 tonnes. In 2003, the company bought the adjacent Bousquet mine property from
In addition, Agnico is exploring two other properties, Goldex, just outside Val d’Or, and Lapa, 10 km from LaRonde, both of which are at an advanced stage of exploration.
The polymetallic LaRonde mine is five times larger than it was eight years ago. At the end of February last year, proven and probable reserves totalled 41 million tonnes grading 4 grams gold and 53.5 grams silver per tonne, plus 0.32% copper and 2.5% zinc, and the inferred resource stood at 14 million tonnes grading 6.5 grams gold, 39 grams silver, 0.35% copper and 0.94% zinc.
The Penna shaft is the newest shaft at LaRonde, and, at 2,250 metres, by far the deepest. The shaft was begun in 1995 and reached its targeted depth in 2000.
Two other shafts have been used to gain access to ore. The No. 1 shaft had a depth of about 1,000 metres; the No. 2, less than 500 metres. A horizontal and an inclined drift connected the developments from near the base of the No. 1 shaft and the Penna shaft.
Agnico is finding substantial reserves below the 2,200-metre level; indeed, ore has been found at a depth of close to 3 km. The company is deliberating on the most efficient way to mine this ore: one possibility would be to deepen the shaft by about 750 metres; another would be to ramp from current depths; a third would be to use the Bousquet 2 shaft, which has a depth of 1,375 metres.
In 1995, LaRonde was being mined at the rate of 2,000 tonnes per day, and five years later, that rate had increased to 5,000 tonnes. Then Agnico-Eagle decided to boost output further to 7,000 tonnes, which necessitated construction of a new hoist and a taller headframe. Today, on average, 6,800 tonnes per day are mined.
Changes have also been made to the mill circuit: whereas only gold and copper were recovered in the past, today silver and zinc are milled as well.
Gold-copper and zinc-silver mineralization is hosted in a felsic unit of the Blake River volcanic group. Massive and disseminated sulphide lenses vary from 1 million to 25 million tons in size.
A road winds around stockpiles of various types of crushed ore, from LaRonde and Bousquet, which will eventually be put through the mill. Concentrate is either trucked to the nearby town of Cadillac, where it is put on a train to Quebec City and loaded on to ships, or trucked to smelters in Rouyn-Noranda or Timmins.
During the summer, a cooling system helps offset the high temperatures at depth. Miners are used to working at 22-24C; without the system, the temperature would be 35-40C. The system was modified and enlarged at the beginning of 2003 at a cost of $8 million. In the past, the system was underground, whereas now it is at surface. Air is drawn past pipes containing water cooled to 2C, and then the cooled air is circulated in the mine. The system is automated and works using ammonium.
In 2000, Shaft No. 1 and Shaft No. 2 were closed. Shaft No. 1 is still used as an emergency exit and for pumping water, whereas No. 2 was allowed to flood to the first level. The water from shaft No. 2 is used in the mine for drilling purposes. The water is re-circulated and suspended particles settle out. No fresh water source is needed for mine operation, which reduces stress on the local environment.
In the past three years, Agnico has developed a system (which it is patenting) for treating tailings that contain ammonium and cyanide. As a result, over the next three years, the water that has accumulated in the tailings area will be treated, the tailings area will be dry, and water leaving the treatment plant will be pure.
The procedure uses different bacteria to process different elements. In 2002, after successfully testing the system in a laboratory, Agnico built a large-scale prototype. When that also proved successful, the company doubled the system’s capacity.
Agnico is using various procedures designed for mining at depth, including electronic blasting. “We’ve been using electronic blasting on a regular basis for the past year and are one of the first operations to do so,” said Mine Manager Daniel Racine. “New mines will be adopting this technology, which was developed by Agnico.”
The mine plan is in place for the next 8-10 years, and additional resources, in a separate area, suggest a possible 15-to-18-year mine life.
LaRonde produces 230,000-240,000 tonnes of ore and moves and reuses about 100,000 tonnes of waste monthly. The mine employs 580, compared with 280 before the expansion.
LaRonde is exceptional in that the employees are not unionized. “In eighteen years, the mine has not lost one day, or even one hour, because of any conflict between management and staff,” Agnico’s manager of Human Resources, Claude Leveillee said proudly. “We work hard to maintain this.”
In the third quarter of 2004, LaRonde produced 67,237 oz., up 31% over the corresponding period of 2003. The recent quarter also saw increases in production of silver (132%), zinc (135%) and copper (7%). The total cash operating cost was $77 per oz. gold.
This year the company will be paying an annual dividend to shareholders for the 25th consecutive year.
Bousquet
Last year, from February through until August, Agnico used open-pit methods to mine about 100,000 tonnes of ore from a shallow deposit in the shadow of the Bousquet headframe.
The deposit had been delineated by Barrick; however, the price of gold was too low at the time for the deposit to be mined profitably.
Agnico is examining other zones to see if they might be economic at the current gold price. However, Normand Bdard, Agnico’s chief exploration geologist at Bousquet, said that although the gold price is higher, the rise in the Canadian dollar in relation to U.S. dollar offsets the price significantly.
The Bousquet 2 mine closed in 2002 after producing 2.2 million oz. gold from 8 million tonnes of ore grading 8.6 grams gold per tonne and 0.67% copper. The ore was downdip of the deposit Agnico mined from shaft No. 1 at LaRonde. The mineralization consisted of gold, silver and copper associated with massive pyrite, semi-massive (silicified, brecciated) sulphides, and stringer sulphides.
A drift has been developed between Bousquet 2 and La Ronde. Agnico hopes to find more ore between the two at depth. Three drills are testing below Bousquet, and results are said to be encouraging.
Agnico also owns the Ellison property, immediately west of Bousquet, and is targeting the same felsic horizon that hosts the Bousquet deposit.
Surface exploration has taught the company that the contact between the Blake River Group and the Cadillac sediments changes at a depth of about 400 metres. The contact, which is vertical up until that depth, becomes shallower and dips in a southerly direction. This knowledge is helping generate more targets.
Lapa
At the time of The Northern Miner’s visit, a final blast at surface had flattened the area adjacent to the shaft. The hoist and headframe from the No. 1 shaft at La Ronde had been dismantled, and both were being transported 10 km to the Lapa property, where they will be reassembled.
Agnico optioned the property from
Agnico drilled 146 holes (86,000 metres of core) over a 400-metre strike length. “We are aggressive in terms of our exploration,” said Graham Long, Agnico’s exploration manager for Canada. “We put the money in the ground and we drill — and we drill a
lot. That is how you find mines.”
Breakwater did a lot of work in the 1980s (even putting in a ramp), but it did not drill at depth.
In mid-2003, Agnico bought Breakwater’s remaining 20% interest in the property for US$8.9 million and a net smelter return royalty of 0.5-1%.
In mid-2004, the Lapa deposit had a probable reserve of 4.5 million tonnes grading 8.9 grams gold per tonne, or 1.3 million oz. A new resource estimate is being calculated.
Lapa has been traced over a strike length of 600 metres. The deposit begins at a depth of 300 metres and has a vertical extent of 900 metres, with a thickness from 3-30 metres. It is still open at depth.
The property overlies the Cadillac-Larder Lake fault zone. Gold mineralization often exists in the hinges of folds associated with this structure. In this same area there is a major contact between mafic-to-ultramafic meta-volcanic rock with sedimentary rocks.
Agnico plans to spend $40 million to firm up the deposit, check its continuity at depth, and take a bulk sample. This year and into 2006, the shaft will be sunk to a depth of about 800 metres, following which the company will take a 13,600-tonne bulk sample.
The current feasibility work should be completed by mid-2006, and if the company decides to mine the deposit, full production is not expected before 2008.
Goldex
Talk about persistence. Agnico is engaged in its seventh program of exploration on the Goldex property, continuing work it began 32 years ago.
Although it is low-grade, Goldex is being tested for bulk-tonnage potential. The deposit has a probable gold reserve of 21.7 million tonnes grading 2.4 grams gold per tonne.
Defining the deposit has not been easy: results from surface drilling in the 1970s led to development of a ramp and bulk sampling, but grades were low. More drilling was done at surface and the zone was found to continue. In 1988, a shaft was initiated and 2-3 bulk samples were taken, but there was a problem with correlation between muck samples and recoveries.
Work continued and, still on the same structure, the latest deposit was found. From 1994 to 1996, the shaft was deepened to 730 metres and development was expanded to provide access to this new area. The mill grade was found to be better than that of the muck. A feasibility study concluded the deposit would be marginal as a stand-alone operation.
Agnico is working to verify the deposit’s continuity and overall grade.
Gold is associated with stockwork quartz-tourmaline veins in a granodiorite sill. A network of quartz veins with various orientations (many dipping at 40 toward the south; others, at 80 toward the north) makes the mass relatively homogenous. The veins contain pyrite along their margins and exhibit chlorite and albite alteration. Shearing, brecciation and folding are evident.
Gold is found as inclusions in pyrite grains or as free gold.
Dewatering lasted three months and was followed by two months of rehabilitation and 1.5 months of drifting. Three raises are being developed simultaneously, from each of which 15,000-20,000 tons will be mined.
The deposit is 1.6 km from the shaft. Agnico figures it will be able to mine at a low cost because of the size of some of the blocks (up to 275 metres high by 365 metres long by up to 120 metres wide).
The raises are 3 metres long by 3 metres wide and will reach 225 metres in height. Development is expected to last about four months. The samples are being stockpiled at Goldex, and a 20,000-ton sample will be processed in January. In addition, vertical holes are being drilled down from the 380-metre level.
The sampling procedure is such that each round is sampled, as well as the muck from each round. These data are compared with historical grade-data. In addition, drilling is being done from the raises. The company is trying to make sure the sampling is representative and not under-estimated.
According to Rosaire Emond, project manager at Goldex, Agnico has always been persistent and ready to “go that extra distance.”
Larger-diameter drill core is being recovered, and the whole core is being analyzed as part of a resource estimate. A minimum amount of core is being kept. Changes have also been made in sample analysis methods.
If a positive decision is reached, full-scale production would likely occur after three years; however, a smaller-scale operation could begin much sooner, since most of the necessary infrastructure is already in place.
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