The looming shutdown of mining at Red Dog has, for the time being, been averted. After lengthy discussions with the U.S. Environmental Protection Agency and a comprehensive review of its operating plans for the zinc-lead mine, Teck Resources Ltd. has decided to begin preparing the Aqqaluk zinc-lead-silver deposit for mining scheduled to begin late this year.
“Our discussions with EPA have been constructive, and after carefully considering the environment, our employees and local communities we are proceeding with Aqqaluk,” said Mike Agg, Teck senior vice president, zinc. “We will continue to maintain a water discharge that is protective of water quality and the environment.”
Though an unachievable dissolved solids limit is still in place, Teck decided to move ahead with Aqqaluk development in order to avoid shuttering the mine by the end of the year due to dwindling supplies of ore in the Main Pit, the deposit the company has been mining for the past two decades.
The decision to prepare Aqqaluk for mining was not one that Teck took lightly. In addition to working with the EPA and state regulators, the company scrutinized its own policies and operational procedures for the Northwest Alaska zinc-lead mine.
“We looked at all the facets of this. The decision to operate and have a permit with an unachievable limit is a significant decision; we want to make sure we get it right,” Jim Kulas, Red Dog’s manager of environmental and public affairs told Mining News May 20.
Procedural wranglingIn its pursuit of the permits needed to develop Aqqaluk, Teck became caught up in procedural wrangling between agencies and environmental law firms.
“This is really a debate/negotiation between legal firms and the EPA over regulations; it’s not about the quality of water,” Teck President and CEO Don Lindsay told investors May 12 at the 2010 Bank of America Merrill Lynch Global Metals & Mining Conference.
The new water permits allow for the discharge of higher levels of total dissolved solids and some metal than those in the previous permit issued in 1998.
Teck was never able to meet the 1998 limits set for total dissolved solids due to the calcium needed to precipitate the metals out of the water during the treatment process.
“Mine drainage water is collected in the tailings pond, treated with lime to remove harmful heavy metals, and discharged in the summer. Although this treatment is appropriate to keep heavy metals out of surface waters, it results in higher concentrations of dissolved solids that are discharged into the creek,” the Alaska Department of Environmental Conservation wrote in a Red Dog Creek analysis report.
The Alaska environmental agency found that the calcium-rich treated water discharged from the mine has diluted the naturally occurring acidic and metal-laden water to a degree that the main stem of Red Dog Creek is now habitable.
“Ten years of aquatic surveys have demonstrated that aquatic productivity in the main stem has increased from premining conditions due to effective water management practices and treatment,” according to the DEC report.
EPA, which agreed with the state agency’s findings, deemed the higher limits safe for aquatic life and consistent with the U.S. Clean Water Act and applied the standards to the Aqqaluk permit.
The two environmental law firms that appealed the permit – Trustees for Alaska and Center on Race, Poverty and the Environment – disagreed with this assessment. The conservation groups argued that the increases in limits violated the antibacksliding provision of the federal law. They also contended that the water discharges under these standards would breach antidegradation laws under the act.
Instead of defending the limits under appeal, EPA decided to withdraw the limits until the State of Alaska developed its ant degradation implementation procedures.
“Instead of defending those five permit limits we have decided to withdraw them and work with the state on improving the antidegradation analysis and then reinstate the permit limits after that. We think that is the quickest course to get those permit limits in effect,” EPA Region 10 Mining Coordinator Patty McGrath told Mining News in March.
Kulas said Alaska regulators are working on putting the required procedures in place, at which point the EPA will renew the Aqqaluk NPDES permit with the standards that were withdrawn as a result of the appeal.
“The state is actively working to develop a better implementation plan and once that is in place, the agency (EPA) plans to renew the permit with those withdrawn conditions back in it, and that will be a more defensible permit should it be appealed again,” Kulas said.
Aqqaluk work beginsWith the go-ahead decision made, crews immediately began mobilizing equipment to the new pit.
“The first thing we have to do is establish our stormwater drainage control. We are planning to get over there this afternoon to start that work,” Kulas said.
Once the sediment control infrastructure is in place, the company has about six weeks of road building before it begins stripping the waste material off Aqqaluk.
“One advantage to this deposit is its proximity; it’s a stones throw from our existing pit,” Kulas explained.
The waste material from Aqqaluk will be placed in the adjacent Main Pit. Once the region that has been the feedstock for Red Dog since 1989 is filled in, it will be contoured to blend with the surrounding landscape.
The Aqqaluk deposit contains some 51.6 million metric tons of reserves with an average grade of 16.7 percent zinc and 4.4 percent lead – enough ore to keep Red Dog in production until 2031.