Introduction of a finer crush and modifications to the grinding and flotation circuits at North American Palladium‘s (PDL-T) Lac des les mine in northern Ontario are starting to pay off with improved performance.
In early October, after lower-than-expected throughput and recoveries thanks to difficulties with a refurbished pebble crusher, unanticipated constraints with the flotation cleaner circuit and a lower-than-expected processing rate at the semi autogenous grinding (SAG) mill, NAP purchased and commissioned a new, larger pebble crusher.
In November, contract crushing began sending finely crushed material to the SAG mill and the flotation circuit in the old mill was connected to the new mill to provide additional cleaner flotation capacity.
During the fourth quarter of 2001, the mill processed more than 1.1 million tonnes of ore running 2 grams palladium per tonne to produce 51,475 oz. of palladium. Recovery rates continued to improve hitting 70.4%. The mine also churned out 4,238 oz. of platinum, 3,817 oz. of gold, 1.2 million lbs. of copper and 604,933 lbs. of nickel.
That’s up from the 910,509 tonnes averaging about 2 grams palladium processed during the third quarter of 2001. In addition to the 36,891 oz. of palladium recovered, the mine churned out 3,347 oz. of platinum, 2,829 oz. gold, 956,935 lbs. copper and 348,015 lbs. nickel. Palladium recoveries in the third quarter 2001 were 62.9% compared to 73.7% in the corresponding period of 2000.
The third-quarter’s startup hiccoughs at Lac des les, combined with lower realized palladium prices, resulted in a third-quarter loss of $2.7 million.
Engineering studies for a secondary crushing facility, to replace contract crushing are underway and a decision on the secondary crusher will be made during the first quarter 2002. The company is also considering modifications to the grinding circuit and possible expansion of the cleaner flotation circuit.
As part of a cost-cutting program, NAP is gearing down mining activity to 54,000 tonnes per day
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