The U.S. Court of Appeals for the District of Columbia Circuit has handed environmental groups a victory in their battle to restrict mountaintop removal mining, but coal advocates say the recent decision is not necessarily the death knell for the practice.

The appeals court ruled on April 23 that the Environmental Protection Agency has the authority under the Clean Water Act to retroactively veto a previously approved U.S. Army Corps of Engineers dredging permit.

In 2011, EPA overturned a 2007 Corps permit issued to the Mingo Logan Coal Co., a subsidiary of St. Louis, Mo.-based Arch Coal, for discharging dredged or fill material from the Spruce I mountaintop coal mine in West Virginia into three streams and their tributaries.

But the ruling is only a partial victory for environmental advocates: The court remanded the case to the federal district court to decide if the EPA's decision violates the Administrative Procedure Act.

Kim Link, spokeswoman for Arch Coal, says that while the company is "disappointed," the court did not rule on the merits of the case, leaving that decision to the lower court. But Earthjustice attorney Emma Cheuse, who helped write the group's amicus brief supporting several of the opponents of mountaintop mining, says it is important the ruling affirmed that the Clean Water Act gives the EPA "the power to protect communities" by revoking formerly approved Corps permits whenever it is necessary to do so. "It's an important backstop" protection for the environment, she adds.

At a Senate appropriations subcommittee hearing on April 24, Lisa Murkowski (R-Alaska) asked EPA Acting Administrator Bob Perciasepe whether the ruling gives the agency broad powers to halt construction projects.

"If the EPA can withdraw, in effect, [an] Army Corps permit at any point, how can you ever give the assurance that any permit is final?" she asked. In response, Perciasepe said the EPA has used its veto authority "very, very sparingly" since the Clean Water Act was enacted in 1972.