Bousquet winding down
The Bousquet mine is in northwest Quebec, between Val d’Or and Rouyn. In production since 1979, Bousquet was one of several Abitibi properties acquired when Barrick purchased Lac Minerals Ltd. in 1994. At that time it was known as the Bousquet complex, with two shafts in operation, linked by underground workings. Difficult ground conditions and high dilution caused the closure of the No.1 shaft in 1996, but the No.2 mine, which opened in 1989, is still in operation.
Ore is trucked 37 km to Barrick’s 2,700-tonne/day Est-Malartic mill.
The Main Zone ore has been mostly mined out, so the current stopes are smaller, in areas of lower grade fringe ore. The mine is clearly approaching its end of life, but is still creating positive cash flow and improving efficiency. Costs per tonne were reduced from Cdn$86 in 1995 to Cdn$61 at the end of the first quarter 2001. Productivity was up from 69 tonnes per manshift in 1995 to 109 tonnes/manshift at the end of the first quarter 2001.
The mining rate in 2000 increased 12% from 1999 because of a number of improvements, such as better mine planning and sequencing, improved equipment maintenance and higher equipment availability. The unit mining costs dropped 3.0% due to better planning, increased mucking productivity and improved production drilling efficiency, even though the stope size decreased and the haulage distance increased from below the shaft.
Likewise, the milling rate increased 12% from 1999 to 2000. The average processing grade last year was 6.3 grams/tonne (g/t) Au, down from 8.5 g/t Au, as the mine was extracting more fringe ore. This caused almost a 2% drop in the recovery rate to 92.7%. The processing cost per tonne dropped 16% due to higher throughput and lower reagent costs.
The mining cost per tonne is expected to drop again this year, and the mine and mill rate to decrease. The grade of the mined and processed ore is expected to be 6.1 g/t Au in 2001. The gold recovery will likely decrease slightly, due to higher production from a zone with a lower recovery rate. The processing cost per tonne is expected to remain the same.
About US$3 million will be spent in 2001 on ore development. A study is underway to evaluate the economic potential of certain known zones, but no exploration program is planned for the year. Bousquet is expected to close permanently in 2003.