VALLEY GROVE - An infiltration of more than 6,000 gallons of "drilling mud" into a Valley Grove home Thursday appears to be part of a larger natural gas pipeline problem, as the fluid also seeped into nearby Little Wheeling Creek twice last week.
West Virginia Department of Environmental Protection spokesman Tom Aluise said about 30 fish - mostly minnows - died in Little Wheeling Creek when drilling fluid pushed up through cracks in the creek's bed. The drilling operation is part of MarkWest Energy's pipeline infrastructure in Ohio County.
"Twice (last) week, they were drilling about 40 feet under the stream when drilling mud infiltrated natural fractures in the rock and entered the surface water," Aluise said of the MarkWest operation, which crossed under U.S. 40 and the creek as it headed south.
He described drilling mud as a non-toxic clay mixture with bentonite as its main ingredient. It is used to lubricate and cool the drill bit and to transport rock fragments and cuttings from the drilling area to the surface.
Aluise said drilling mud entering a creek through cracks in the creek bed is not an unusual occurrence.
"It happens," he said. "In the industry they call it inadvertent return."
Aluise said after the fluid entered the stream, MarkWest crews used sand bags to dam the area and create a pool containing the mud to prevent it from flowing downstream and into Wheeling Creek.
"They will do a complete stream remediation after the drilling is completed," Aluise said.
He said the DEP has notified the West Virginia Division of Natural Resources that workers found about 30 dead fish, including minnows, barters and two crayfish.
"MarkWest may be cited for violations impacting the state's water," he said. "That decision will probably be made within the next few days."
Just what killed the fish remains unclear, as both MarkWest and DEP officials agree that drilling mud is non-toxic.
Aluise said "a huge amount of mud concentrated in a small area robs the water of oxygen and little fish cannot survive in that environment."
MarkWest spokesman Robert McHale said the fish died because their water was taken away.
"I believe the reason we have dead fish is because we de-watered the affected area," he said.
He explained that workers dammed the water upstream and downstream on either side of the drilling mud, and created a bypass for clean water to flow through the area. The dead fish became trapped in the dry area.
Benjamin Stout, a biology professor at Wheeling Jesuit University, wants proof the fluid is non-toxic.
"The facts do not add up," he said. "They should do a laboratory sampling (of the drilling mud) and show us the results. That will tell if it is non-toxic."
The pipeline issue is not the first in the region for MarkWest.
In August, the DNR cited the company for "conditions not allowable in the waters of the state" after a landslide ruptured a natural gas liquids pipeline causing a fish kill in Rocky Run, a tributary of Fish Creek in Wetzel County.
McHale said MarkWest is working with state regulators to resolve the Wetzel County citations and he expects more citations because of the Little Wheeling Creek event.
"The Wetzel County accident was an isolated incident and there is no reason to believe it will happen again," he said. "As far as the Valley Grove problem, we are doing everything we can to minimize the potential for inadvertent returns to happen again."
He said the DEP is vigorous in enforcing state regulations but the agency is easy to work with.
"We will continue to cooperate and work in full transparency with the state Department of Environmental Protection," McHale said.
Another drilling mud spill occurred earlier this month in Harrison County near Cadiz when the substance ran into Conotton Creek and onto the properties of two homeowners, affecting their private drinking water. The spill occurred during construction of the ATEX pipeline, which will carry liquid petroleum products from Pennsylvania to Texas.