High and dry

WALLACE - When people in North Idaho's Silver Valley heard that decades of mine waste was going to be cleaned up there was a lot of angst about where it would all go.

Which is understandable - some piles are built up like rocky, barren hillsides.

Now, high up in the Nine Mile Creek drainage, on property owned by Coeur d'Alene Trust, a major waste consolidation area is being developed. The Coeur d'Alene Trust was set up through a settlement with Asarco.

All of the mining waste from the Interstate-Callahan and Success mines will go to a spot high and dry near the East Fork of Nine Mile Creek.

"It'll be a lined facility and it will be capped, and maintained in perpetuity," said Bill Adams, Coeur d'Alene team leader for the U.S. Environmental Protection Agency.

Waste from the Interstate-Callahan, much of which ended up polluting the watershed for decades, is already being picked up and hauled to the waste consolidation area where it will do no more harm.

"It's very impressive in terms of the size of this thing," Adams said.

CDM Smith, in Kellogg, designed the waste consolidation area project. Workers and heavy machinery were busy this week at the site, which is high enough to limit the construction window to summer and early fall.

"In all, this thing is going to hold about 1.3 to 1.5 million cubic yards of waste," said Cody Lechleitner, the project manager for CDM Smith. He spoke Wednesday during a tour of the project, hosted by the EPA, for community and government officials.

The project cost approximately $8 million, including property acquisition, design and construction.

Completion of the project depends on the cleanup pace. The cleanup of the East Fork of Nine Mile Creek is estimated to take 10 to 12 years, then the cover would be placed on the waste consolidation area.

That cover will include an impermeable liner, three feet of soil and vegetation.

There are expansion possibilities - all the way up to 2 million cubic yards - if there ends up being more waste than is currently estimated.

"That one will cost a little bit more, but it is possible, and we've proven that in the design," Lechleitner said.

At the site, it's hard today to imagine what it will all look like when the work is complete.

"We're basically going to create an artificial ridge," said Lechleitner.

The tour Wednesday included a stop at Silver Hills Elementary School in Osburn, where project managers got to show off a recently completed $1 million "remedy protection project."

From the hillside south of town, Shields Gulch regularly floods the school property during spring runoff and snowmelt events.

The gulch runs by the Coeur Mine, and its waste rock pile comes down near the stream channel.

"There's a potential for recontamination, as well as a lot of scour from the water coming down through this area," said Jim Finlay, assistant program manager for the Coeur d'Alene Trust.

The remedy protection project channels the water through the community so it doesn't scour out remediated areas like Silver Hills or spread contamination during run-off events.

The project is designed to handle a 50-year rain-on-snow event.