WASHINGTON – The federal government in a report due out Thursday is calling for changes in how the government regulates mountaintop coal mining, in which Appalachia’s ridges are blasted away and rocks and dirt are dumped in valleys and streams.

Coal operators have increasingly relied on the practice for its efficiency, but environmentalists say this type of mining violates the Clean Water Act and must be stopped.

The report, which was obtained by The Associated Press, recommends agencies better coordinate the way they regulate mountaintop mining.

But the report does not address environmental demands to set limits on the size of valley fills, where dirt and rock are pushed into nearby stream beds.

The report recommends finalizing an Interior Department proposal that would allow valley fill to be placed in streams, something current surface mining law generally does not allow.

The focus of the study involves about 12 million acres and 59,000 miles of streams in Kentucky, West Virginia, Virginia and Tennessee.

The study was required as part of an out-of-court settlement of a 1999 federal lawsuit that challenged the way West Virginia permits and regulates mountaintop removal strip mines.

A West Virginia judge ruled twice in recent years that mountaintop mining violated environmental laws, but he was overturned both times.

Five agencies have been at work on the new study since 1999: Office of Surface Mining, the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service and the West Virginia Department of Environmental Protection.