TORONTO (miningweekly.com) – Base metals producer Imperial Metals reports that the Red Chris mine, in north-west British Columbia, increased copper and gold production by 14% and 23%, respectively, during the second quarter ended June, producing some 26.74-million pounds copper and 18 213 oz gold.
The TSX-listed miner on Friday advised that the mill achieved an average throughput of 28 971 t/d, and the mine moved an average of 75 002 t/d of material during the period.
The bulk of the mill feed (about 77%) was mined from the Main zone, with higher-grade East zone ore providing the remainder of the mill feed. The ore grade averaged 0.59% copper and 0.40 g/t gold for the quarter.
Metal recoveries averaged 78.24% copper and 53.53% gold, down slightly from the 79.1% and 54.72% achieved for copper and gold respectively in the first quarter of 2016. Metal recoveries were negatively impacted by near-surface (higher clay content) ore delivered from a Main zone pushback that made up about 24% of the feed during the June quarter, compared with 0% in the first quarter of 2016, the company advised.
Meanwhile, full operations at the Mount Polley mine have been restarted following the August 2014 tailings breach and environmental disaster; it treated 1.57-million tonnes of ore, producing 5.31-million pounds copper and 9 476 oz gold.
The ore grade fell and averaged 0.22% copper and 0.28 g/t gold in the quarter, compared with 0.31% copper and 0.33 g/t gold in the prior quarter. Lower head grades resulted in lower metal recoveries averaging 68.33% copper and 67.62% gold.
Grades were lower as underground operations in the Boundary zone supplied 55 582 t grading 0.91% copper and 0.55 g/t gold, down from 91 881 t grading 1.73% copper and 1.1 g/t gold, Imperial stated. A fill cycle in the main Boundary stope was completed during the quarter and production from the underground operation is targeted to increase in the third quarter.
Meanwhile, slowing output from its Huckleberry mine for the second quarter was in line with targets. Throughput averaged 19 426 t/d, producing 7.71-million pounds copper in the period. The copper grade averaged 0.23%, while copper recovery was 87.6%.
Imperial said it will continue milling the stockpiles until the end of August 31, when it will suspend operations and place the operation on care and maintenance, pending an increase in the price of copper.