Idaho mining clean-up could cost $635 million

The massive cleanup of a century's worth of mining pollution in Idaho's Silver Valley would cost $635 million and take up to 30 years under a final plan approved by the federal government on Tuesday.

The U.S. Environmental Protection Agency released the interim Record of Decision Amendment, which details its proposal to clean up arsenic, lead and other heavy metals pollutants in the valley, which is located 50 miles east of Spokane.

A lawsuit calling for the cleanup was originally brought in 1991 by the Coeur d'Alene Indian Tribe against several mining companies. Agreements have since been reached with several mining companies that had historic operations in the valley, creating a trust fund of about $800 million to pay for the work.