I’m not entirely well-versed on the Administration’s policy on mountaintop mining, but to the extent that I do come across the various proposals, they have vacillated back and forth a bit. Last April it seemed like an EPA rule on the practice, which entails blowing off the top of a mountain to extract resources, allowing debris to flow into streams and water supplies, would effectively ban it. Yet, several large-scale projects moved forward at the same time. And before the April rule, the EPA allowed some mountaintop mining permits.

But today, the EPA flat-out revoked the permit for one of the largest mountaintop removal projects in the nation.

The Environmental Protection Agency revoked the permit for one of the nation’s largest mountaintop-removal coal mining projects on Thursday, saying the mine would have done unacceptable damage to rivers, wildlife and communities in West Virginia.

Arch Coal’s proposed Spruce No. 1 Mine in Logan County has been the subject of controversy since the Bush administration approved its construction in 2007, issuing a permit required under the Clean Water Act. Environmentalists and local residents strongly opposed the sprawling project, and the Obama administration moved last year to rescind the permit, prompting lawsuits by West Virginia and the coal company.

The agency’s action on Thursday is certain to provoke an outcry from West Virginia politicians, the coal industry and other businesses that have raised objections to what they consider economically damaging regulatory overreach by the E.P.A.

EPA revoked the permit, offered in 2007 under the Bush Administration, using its authority under the Clean Water Act. At their website they have several findings, showing the impact of mountaintop removal at the Spruce No. 1 mine, including wildlife and water quality. “The proposed Spruce No. 1 Mine would use destructive and unsustainable mining practices that jeopardize the health of Appalachian communities and clean water on which they depend,” said Peter S. Silva, the agency’s assistant administrator for water, in a statement. “Coal and coal mining are part of our nation’s energy future, and E.P.A. has worked with companies to design mining operations that adequately protect our nation’s waters. We have a responsibility under the law to protect water quality and safeguard the people who rely on clean water.”

I’d expect the mining company and potentially even the state of West Virginia to take action against this ruling; last year West Virginia sued the federal government over the April restrictions. So we probably have a way to go on this.

Still, the EPA appears to be swinging in the direction of more oversight, not less, of clean water, and ending the practices that pours coal slurry and residue into Appalachian streams.