Alpha officials did not immediately respond to requests for comment Tuesday, but told the Associated Press last week they are confident the facility is safe.
Earlier this year, in response to complaints from Stanley, OSM issued an enforcement notice to give the state DEP time to explain whether the dam showed any signs of interior pressures that would indicate wet refuse used to expand the dam was making it unstable.
Initially, DEP officials in late May issued an order in which they asked the company to conduct new testing to determine if there was a problem.
But at a meeting last week, company officials told DEP and OSM that they already had some new data that would support their contention that the dam was safe. Company officials, though, did not bring the data to the meeting, and OSM extended the deadline until early August for the company to provide the data and for federal officials to review the matter.
DEP mining officials said Tuesday that their examination so far had found what they called "slightly elevated pressures" on monitors meant to keep track of whether liquid wastes were filling up voids between solid wastes, potentially causing dam stability problems.
Harold Ward of the DEP's Division of Mining and Reclamation, said his agency plans to closely examine the additional data from the company. "We don't want to leave anything uncovered," Ward said.
Calhoun said he's also still reviewing the matter, and didn't want to publicly discuss what his agency has found so far until the investigation is completed.
So far, though, OSM's review has prompted DEP to add requirements into a separate permit for Alpha's nearby Bee Tree Surface Mine to limit vibrations any blasting there causes at the Brushy Fork site. DEP had previously argued such limits weren't needed.
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.