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Construction enters final phase, but monitoring will continue at Mike Horse Mine

Mike Horse Cleanup
Posted at 8:57 AM, Oct 06, 2019
and last updated 2019-10-06 15:25:11-04

LINCOLN — The multi-year effort to remove contaminated soil from the Upper Blackfoot Mining Complex is entering its final phase but state officials say it will take many years of monitoring before they know how well the cleanup is working.

The Montana State Department of Environmental Quality, the US Forest Service and other agencies have been tackling the serious contamination problems at the headwaters of the Blackfoot River for nearly 20 years.

Using upwards of $60-million in legal settlements with ASARCO, they began removing the failing Mike Horse Dam in 2014, along with a cleanup of the mine site, and toxins that spread downstream in the mid-1970s.

This weekend, MTN News joined DEQ on a tour of the project site just west of Rogers Pass, where the valley has been transformed over the past five years.

The mine site itself has been completely cleaned up, nearly a million cubic yards of soil has been moved to a repository and miles of Mike Horse and Beartrap creeks are being restored, complete with vegetation.

DEQ Project Manager Dave Bowers says it's too early to declare "victory", but all the early indications are positive. Sampling shows major reductions of lead and arsenic. Some fish even showed up this year.

"You know, we didn't really start in the environmental remediation/restoration business until the late 1980s. And so we're really, really a young industry from that perspective. And learning so much," Bowers said. "And there's new stuff coming along all the time."

Bowers says some of the accomplishments at Mike Horse are being analyzed by other states which are also dealing with the problem of historic mine waste.