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By Scott DiSavino
Aug 6 (Reuters) - A U.S. appeals court on Monday vacated permits by two federal agencies that allowed Dominion Energy Inc to build its Atlantic Coast natural gas pipeline, a decision the company does not expect to hold up its $6.0 billion to $6.5 billion project.
In response to the court's concerns about the environment, Dominion said it would work with the agencies to reinstate the permits for the 600-mile (966-km) pipe from West Virginia to Virginia and North Carolina.
"We believe the court's concerns can be promptly addressed ... without causing unnecessary delay," Dominion spokesman Aaron Ruby said in an email.
In the meantime, Ruby said Dominion will continue work in West Virginia and North Carolina. The company has said it expects to finish the 1.5-billion cubic feet per day pipe by late 2019.
One billion cubic feet is enough to fuel about 5 million U.S. homes for a day.
The ruling was the latest victory for the Sierra Club and other opponents of gas pipelines in the 4th U.S. Court of Appeals.
Last week, the court told EQT Corp to stop work on its Mountain Valley pipeline from West Virginia to Virginia after voiding two federal permits for that project.
Atlantic Coast and Mountain Valley are two of several pipelines under construction to connect growing output in the Marcellus and Utica shale basins in Pennsylvania, West Virginia and Ohio with customers in other parts of the United States and Canada.
In the Atlantic Coast case, the Sierra Club and others challenged decisions by the U.S. Fish and Wildlife Service and the National Park Service.
The Fish and Wildlife Service issued an Incidental Take Statement under the Endangered Species Act authorizing the company to build the pipeline in areas inhabited by threatened or endangered species, including mussels, bumble bees, crustaceans and bats.
The court wants Fish and Wildlife to put more limits on how the company deals with the animals in a 20-mile portion of the pipeline's route in West Virginia and 80 miles in Virginia.
Dominion said it will avoid those areas until the agency clarifies the limits, which the company expects shortly.
The court wants the National Park Service to better explain why permitting a pipeline to cross under the Blue Ridge Parkway in Virginia is consistent with the conservation and preservation purpose, including scenic views, of a national highway.
Dominion said it expects the Park Service to provide the information and promptly reissue the permit.
Reporting by Scott DiSavino; editing by Jonathan Oatis and Lisa Shumaker