May 16, 2012 in Idaho

Silver Valley decontamination begins

By The Spokesman-Review
 

The first big dollars are starting to flow out of a $460 million trust fund established to pay for cleanup of mining pollution in Idaho’s Silver Valley.

About $8.5 million will be spent this year from the Asarco trust, which was created as part of the company’s 2009 bankruptcy settlement to pay for environmental liabilities in the valley.

This year’s work targets historic mine operations that leach heavy metals into the Coeur d’Alene River system, said Dan Meyer, the trust’s senior project manager.

Beginning in the late 1800s, Burke and Nine Mile canyons were home to dozens of silver/lead mines and ore processing operations. Early industrialists built fortunes from the minerals pulled out of the narrow mountain canyons, but historic photographs also show the leftover waste rock being pumped directly into creeks that flow into the Coeur d’Alene River.

Not only the creeks, but the flood plains are choked with mine tailings. As water filters through those rocks, it picks up lead, zinc, cadmium, arsenic and other metals. Both canyons are large contributors to the river’s overall metals load.

Water flowing out of Nine Mile Canyon, for instance, has about 20 times as much lead and zinc as the state’s water quality standard, said Bill Adams, a project manager for the U.S. Environmental Protection Agency. Stretches of the creek are sterile because the high minerals content is toxic to fish and other aquatic creatures, he said.

The year’s work will focus on defining the extent of the pollution and designing cleanup plans, Meyer said. The actual cleanup work will come later.

Asarco was a longtime mining operator in Idaho’s Silver Valley whose cleanup liability was settled through the courts. Trust managers anticipate funding $8  million to $10 million worth of cleanup work annually during the Asarco trust’s early years, to allow the principal to continue to grow.

In other Superfund news, Silver Valley communities will receive an estimated $100 million over the next six to eight years to fix deteriorating roads and culverts that contribute to the spread of heavy metals.

The money will bring an influx of construction work to the small towns while reducing the risk of exposure to metals, said Terry Harwood, executive director of the Basin Environmental Improvement.

Many of the valley’s roads were built on mine tailings, so potholes can become pollution sources. Officials have documented rust-colored liquid from oxidized metals oozing out of cracked asphalt, Harwood said. In addition, the gravel used for some unpaved roads was crushed mine tailings.

The $100 million worth of work also includes projects intended to reduce the spread of heavy metals that occurs during floods, Harwood said.


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