May 2011

Today’s record becomes tomorrow’s standard

Early production sets a fast pace at IAMGOLD`s Essakane Mine in Burkina Fasso

By Dan Zlotnikov

Essakane is the first gold mine brought into production by IAMGOLD | Photos courtesy of IAMGOLD

The Essakane Mine, about 320 kilometres northeast of the country’s capital of Ouagadougou, entered commercial production last year on July 16, and its importance for IAMGOLD cannot be overstated. Despite being in operation for less than half a year, in 2010 the mine produced 122,000 ounces of gold. The forecast for this year is 370,000 to 390,000 ounces, making Essakane, which the company acquired from Orezone Resources Inc. in 2008, a major part of IAMGOLD’s mine portfolio.

By contrast, the Rosebel Mine in Suriname, the company’s current flagship mine, produced 395,000 ounces last year and is expected to produce between 360,000 and 380,000 in 2011. The company owns 90 per cent of Essakane and 95 per cent of Rosebel, with the national governments in Burkina Faso and Suriname, respectively, owning the remainder. All production figures above are the portion attributable to IAMGOLD.

A head start

The timing of the mine entering production – two months ahead of schedule – was made possible by starting production before the crusher came online, says Brian Chandler, IAMGOLD’s senior vice-president for African operations. “We were feeding the feeders with a backhoe and trying to sort out the rocks as we did that,” he explains. “The process became much smoother when the crusher went into service in late September, but going ahead without the crusher in the process allowed the mine to begin producing gold with a few months’ head start.”

The early startup owes quite a bit to the softer laterite material making up parts of the Essakane deposit. This material enabled the mine operators to temporarily avoid having to use the crusher, and it also requires less crushing time in general, which allowed for another major improvement in the mine’s productivity.

Originally, the open pit operation was designed to process 7.5 million tonnes of ore, says IAMGOLD’s COO Gord Stothart, with crusher throughput being the major limiting factor in the plant. But when processing the softer rock, that throughput improved significantly, moving the bottleneck to the plant’s tailings system, where the company found it could make improvements. “We modified the tailing pumps to allow us to get a little more through there,” says Chandler. “That’s probably the biggest single adjustment.”

By initially focusing on the soft rock, Essakane was able to go from the original volume projections to as much as nine million tonnes of annual throughput. However, these benefits come with an expiry date. “The soft rock, we know from our current reserves, only lasts until about 2013 at which time we get into hard rock, and the nominal design on hard rock is 5.4 million tonnes,” explains Stothart.

Expansion studies underway

Needless to say, IAMGOLD is highly motivated to find more gold-bearing soft rock on its lease territory. Stothart says that in 2010, the company completed a drill delineation program of more than 40,000 metres at Essakane for $13.4 million, and is expecting to make similar efforts this year. “It’s almost 1,300 square kilometres of land that we have there, and it’s very good prospective land that we have in our exploration concessions,” he adds. “So we think that there’s a real opportunity to extend and expand Essakane.”

According to Chandler, the company is planning ahead in another way, anticipating a time when the mine must switch to hard rock processing. “We’re doing some expansion studies right now, working on feasibility to expand the operation at Essakane,” he says. Part of the limitation of the current plant will be the crusher capacity, since the harder material will require additional crushing time. The other major constraint is water. The Sahel region of Burkina Faso gets very little rainfall and the nearby river is completely dry for most of the year. This means the company must manage its water use very carefully.

“The original design says that we would only process 5.4 million tonnes of hard rock a year, so the expansion is all about what can we do to make sure that once we’re up to around 10 million that we stay there,” says Chandler. The feasibility study of the possible expansion is scheduled to be completed later this year.

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