A company constructing a natural gas pipeline in Greene County is facing a state citation for allegedly allowing 500 gallons of bentonite drilling mud to escape from a bore hole into a tributary of Dunkard Creek.
The Department of Environmental Protection (DEP) said it will issue a notice of violation to Equitrans for the “mess” in Garrison Fork, a small tributary in Gilmore Township, said DEP spokesman John Poister.
About 500 gallons of a mixture of bentonite, a non-toxic clay-like substance used in drilling, and water flowed out of a hole being drilled under Garrison Fork and entered the creek on April 11, Poister said. Equitrans was in the process of drilling a 2,800-foot hole under the creek for a 24-inch pipeline when the “inadvertent return of drilling mud” occurred, he said.
The spill occurred during work on Equitrans’ “Sunrise Project,” a 45-mile pipeline from southwestern Pennsylvania into northern West Virginia. Equitrans is a subsidiary of EQT Corp. of Pittsburgh.
Bentonite is commonly used in the gas industry to extract drill cuttings from bore holes, seal the bore and lubricate drill heads.
Workers at the site cleaned up most of the material, but their efforts also left the creek cloudy, Poister said, adding that bentonite expands when mixed with water.
“They had a real mess in the creek,” Poister said. “We think the stream impact was severe.”
He said water samples were taken for testings, but he did not know whether aquatic life was harmed. Although bentonite it is non-toxic, high concentrations can clog fish gills, he said.
DEP officials are supposed to return to the site today for a follow-up inspection and, possibly, a biological survey, Poister said.
The Sunrise Project is intended to deliver new gas from the Marcellus shale region to northeastern and Mid-Atlantic markets using Equitrans’ existing Mainline System to feed gas to the Sunrise line.
In addition to the pipeline, the project involves building a 14,205-horsepower compressor station, replacing 2.6 miles of inactive line with a 20-inch pipeline and installing interconnections with other lines in Greene County.