At toxic Montana dam, a river now runs through it

By Jeff Hull

MILLTOWN, Montana (Reuters) - Engineers breached a hydroelectric dam in Montana on Friday, the first time an American dam was removed to clean up toxic sediments captured behind it from years of mining upriver.

The intent was the restore some of the pristine beauty of the water as portrayed in "A River Runs Through It," Norman McLean's classic novel about fly fishing later made into a film directed by Robert Redford.

In the novel, the Blackfoot, one of the rivers dammed in Milltown, is portrayed as a frontier of unspoiled outdoor recreation.

In reality, the reservoir behind the 720-foot-(220 meter)wide, 21-foot-(seven meter)high Milltown dam east of Missoula held 6.6 million cubic yards of sediment laden with arsenic, zinc, copper and other heavy metals. The sediments came from a century of mining at the river's headwaters in Butte, 120 miles upstream.

Its breaching represents the first time a dam has been taken out specifically as part of a multiyear process to clean up a toxic river bottom. The lower water level with the dam gone will allow engineers easier access for cleaning.

Contractors will spend several years digging up toxic sediments 25-feet-(eight meter)deep in some places. Eventually, the former reservoir is slated to become a recreation area.

In Montana, as in many Western states, cleaning up after mining has become a big business. The Milltown dam's removal is part of a $500 million Superfund clean up project, led by the U.S. Environmental Protection Agency.

"They used to say it's jobs or the environment," said Montana Governor Brian Schweitzer. "Take a look at those yellow tractors. Those are jobs restoring the environment."