The U.S. Environmental Protection Agency approved the repeal of a 1983 law that prohibited surface coal mining within 100 feet of flowing streams. Most U.S. surface coal mining is done in the steep mountains of Appalachia, across Virginia, West Virginia, Tennessee and Kentucky.
EPA's approval was the last hurdle for a proposal that originated at the Interior Department's Office of Surface Mining. The rule goes into effect 30 days after publication in the Federal Register, which has not yet occurred.
This will allow more mountaintop-removal mining, where coal is mined by blasting off the tops of mountains and the crumbled mountaintop debris is pushed into adjoining valleys, environmental groups said in a statement.
"The EPA's own scientists have concluded that dumping mining waste into streams devastates downstream water quality," said Ed Hopkins of the Sierra Club. "By signing off on a rule to eliminate a critical safeguard for streams, the EPA has abdicated its responsibility and left the local communities that depend on these waters at risk."
Some 126 million tons of coal came from U.S. mountaintop mining in 2007, accounting for 10 percent of U.S. coal production, said Carol Raulston of the National Mining Association.
Raulston disputed the environmentalists' charges, saying the new rule was "merely a clarification of what is required in order to conduct any type of mining activity."
Mountaintop mining is safer for miners than underground mining, but its ecological impact has drawn fire from local communities and environmental activists.
More than 400 mountaintops have been stripped of trees and flattened, 1,200 miles of mountain streams have been buried under mining debris since mountaintop mining began in earnest, the groups said in a statement after EPA approved the rule.
"The EPA's decision is a slap in the face of Appalachian communities, which have already endured enough injustice from mountaintop removal," said Vernon Haltom of West Virginia-based Coal River Mountain Watch. "My home and thousands of others are now in greater jeopardy."
The U.S. environment agency said in a statement that it worked closely with the Office of Surface Mining to "enhance environmental protections in the final rule, including requirements that no mining activities may occur in or near streams that would violate federal or state water quality standards."