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Mining News: Red Dog Mine operator, Teck Resources, orders two new mills
Teck Resources Ltd. has purchased two new M3000 IsaMills equipped with 1.5 megawatt motors for its Red Dog zinc mine in Northwest Alaska. The new equipment will be used to grind harder ore from the Aqqaluk deposit adjacent to the mine’s main deposit.
The regrind circuit at Red Dog currently uses 10 vertical tower mills. The IsaMills will replace seven of them. One mill will regrind materials to 13 microns, and the other to 25 microns after the first phase of flotation.
The IsaMill was originally designed to improve efficiency and metallurgy of ultra-fine grinding. It was later discovered that the mills work well at coarser sizes, providing a more energy-efficient operation with the added advantage of improved recovery.
Because of Red Dog Mine’s remote Arctic location in Northwest Alaska, it uses diesel generators to power its operations. Thus, energy efficiency was the primary motivator for Teck to upgrade the mine’s regrind circuit.
The mills are expected to be commissioned and installed by the first quarter of 2010, in time to begin grinding ore from the Aqqaluk deposit.
Permitting Aqqaluk In May 2007, Teck asked the U.S. Environmental Protection Agency to modify its water discharge permit issued under the National Pollutant Discharge Elimination System to include development of the Aqqaluk deposit.
This modification to the NPDES triggered a National Environmental Policy Act review, with EPA as the lead regulatory agency. A Supplemental Environmental Impact Statement must be completed to update Red Dog’s environmental impact statement, which was developed in 1984 when regulators issued the first NPDES permit for the mine’s discharges.
Teck is currently working to complete environmental permitting for the Aqqaluk deposit. Distribution of the draft SEIS is expected around mid-November.
The Aqqaluk deposit borders the northeast edge of Red Dog’s main deposit. It contains 51.6 million metric tons of reserves, grading 16.7 percent zinc, 443 percent lead and 79 g/t silver.
Teck Cominco intends to begin developing the Aqqaluk Pit in 2010. Ore from Aqqaluk would initially be blended with ore from the main deposit, at a combined production rate of about 3.3 million metric tons per year, which is the same as current and planned production rates from main pit operations. In 2012, when ore from the main deposit is projected to be depleted, the entire mine’s production would then come from the Aqqaluk deposit.
—Shane Lasley
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