The effluent pipeline study was conducted under a 2008 Settlement Agreement and Consent Decree that resolved litigation under the Clean Water Act. Under the agreement, Teck Alaska agreed to review the feasibility of constructing a pipeline to carry effluent from the Red Dog mine along the DeLong Mountain Transportation System (DMTS) to a marine discharge at or near the DMTS port site.

Teck Alaska conducted engineering, geotechnical, environmental and other studies to look at various pipeline options at a cost of $1.7 million. The studies determined that an underground pipeline is not a technically feasible option because it would be vulnerable to breakage due to ground movement caused by seasonal ground freezing and thawing.

The studies also determined that an above-ground pipeline is not a viable option. While potentially technically feasible, the above-ground pipeline would result in no demonstrable environmental benefits, the Tech announcement said. Rather, there would be increased environmental risks and impacts associated with pipeline construction and operation, energy use and emissions, and potential effects on caribou migration.

Further, the estimated $261 million capital cost of an above-ground pipeline would be prohibitive, Teck said.

As stipulated in the Consent Decree, Teck will pay a civil penalty of $8 million in connection with its decision not to construct the pipeline.

“Following extensive environmental and technical study, it is clear that a pipeline is not a viable option,” Henri Letient, general manager, Red Dog Operations, said. “More importantly, there is no clear environmental benefit to building a pipeline, as the treated water currently being released to Red Dog creek meets stringent permit requirements and is fully protective of aquatic and human health. In fact, the creek is demonstrably healthier than it was before mining commenced, supporting a thriving fish population because of our water treatment program.”

Red Dog’s production of metal in concentrates in 2014 is expected to be in the range of 500,000 to 525,000 mt of zinc and 95,000 to 100,000 mt of lead.