Montana is loaded with mining operations that have gone awry, leaving the state to deal with toxic waste and contaminated water. The copper mines of Butte and the Zortman-Landusky Mine near the Fort Belknap Reservation are two of the more egregious cases. But a small 1940s-era lead mine near Rogers Pass has its own notoriety.

In 1975, the Mike Horse Mine impoundment failed in the headwaters above Lincoln, causing 200,000 cubic yards of toxic waste to slide down the canyon and into the upper reach of the Blackfoot River. Four decades on, scientists still find traces of lead and zinc from the mine in the river, and fishermen complain that trout populations have not fully recovered.

For about the past decade, the Montana Department of Environmental Quality and the U.S. Forest Service have worked in fits and starts to reclaim the Mike Horse Mine and the spill area below. This summer, the derelict impoundment is being demolished.

Read more in my story on the DEQ reclamation and the mine's history here.