Patriot Coal is being sued by environmental groups who say the company's Hobet 21 mountaintop removal mine in Southern West Virginia is polluting the Mud River watershed.
The Ohio Valley Environmental Coalition, West Virginia Highlands Conservancy, and the Sierra Club say they have identified multiple violations of water quality standards at the Boone County mine. The groups say streams in the watershed are no longer healthy ecosystems because of pollution from more than 20 valley fills.
Patriot Coal didn't immediately respond to a request for comment on Tuesday.
The groups say the mine's pollution permit prohibits dumping materials into waterways in concentrations harmful to humans, animals or aquatic life, or concentrations that significantly affect aquatic ecosystems.
The groups say they filed their complaint on Monday in federal court in Huntington.