The U.S. Forest Service has agreed to withdraw for further environmental review a plan to expand Utah’s biggest-producing coal mine, the Salt Lake Tribune reported.

The Forest Service last year approved a plan by Arch Coal subsidiary Ark Land Co. to lease 2,500 ha (6,175 acres) of coal beneath the Fishlake and Manti-La Sal national forests. The plan would essentially expand the company’s underground SUFCO mine east of Salina. But the Utah Environmental Congress and other groups appealed the decision on grounds that it violates the agency’s roadless rule and could threaten sage grouse.

Fishlake National Forest Supervisor Allen Rowley withdrew the approval.

The decision does not mean the expansion is thwarted, but rather that the agency will conduct more studies before deciding.

“Because of the appeal we are going to look at what we need to do to be able to get it approved,” Fishlake spokesman John Zappell said.

The plan calls for mining nearly 52 mt (57 million st) of coal. The minerals are managed by the U.S. Bureau of Land Management, but the surface is on forest land and the lease needs approval from both agencies.