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By Shane Lasley
North of 60 Mining News 

Impact of pipeline proposal worries regulators

Influenced by water discharged from the mine, Red Dog Creek now supports aquatic life; proposed bypass could change that

 

Last updated 9/28/2008 at Noon



Some Alaska regulators are expressing concerns about a proposal to build a 55-mile pipeline to discharge wastewater from the Red Dog zinc-lead mine in Northwest Alaska.

The proposed pipeline, one of the items included in a lawsuit settlement between Teck Cominco Alaska Inc. and six residents of the village of Kivalina, would discharge treated wastewater from Red Dog, the world's largest zinc producer, directly into the Chukchi Sea, bypassing Red Dog Creek which flows into the Wulik River, a waterway used for drinking water by Kivalina residents.

What concerns some regulators is the possibility that if Red Dog Creek no longer receives water discharged from the mine, the tributary will return to its natural state, which was too toxic to support the fish that have moved into the stream since the mine opened.

Balanced pH and consistent flow

A 2005 U.S. Environmental Protection Agency report cited two reasons for increased aquatic life in Red Dog Creek as a result of water being discharged from the mine.

Prior to the Red Dog Mine, fish could not survive in the creek due to naturally occurring high levels of cadmium, lead, zinc, aluminum and low pH levels, according to the report. However, the discharge of treated wastewater from the mine into the creek has enabled Arctic grayling to migrate to the stream.

Discharge from the mine also has resulted in more consistent flows in the main stem of Red Dog Creek, which has helped aquatic life to develop, according to the report. If the mine discharges were discontinued, aquatic productivity in the stream would decrease, the regulators say.

Agencies conclude discharge not harmful

"Ten years of aquatic surveys have demonstrated that aquatic productivity in the main stem (of Red Dog Creek) has increased from pre-mining conditions due to effective water management practices and treatment," researchers for the Alaska Department of Environmental Conservation said.

But Kivalina residents object to being exposed to calcium-dominated solids in the treated wastewater, which are produced by the lime that the mine uses to remove metals from its wastewater.

The Alaska Department of Environmental Conservation and the U.S. Environmental Protection Agency studied the effects of the treated water discharges from Red Dog and concluded that they are not harmful. In fact, the balancing of pH caused by the treated water has contributed largely to the creek being habitable by grayling.

After the grayling moved into Red Dog Creek, a site-specific criterion for total dissolved solids was developed to protect them while spawning. These changes to Alaska's water quality standards were approved by the U.S. Environmental Protection Agency.

 

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