Boring a tunnel to allow a natural gas pipeline to cross under Interstate 81 will be an around-the-clock job that may take the rest of this year.
Mountain Valley Pipeline was given permission last week by the Federal Energy Regulatory Commission to drill horizontally – 24 hours a day, seven days a week – about 50 feet below I-81 in Montgomery County, just north of the Ironto exit.
The boring, which will be largely out of view to passing motorists, is not expected to impact traffic, according to Jason Bond, a spokesman for the Virginia Department of Transportation.
A contractor doing the work started Nov. 9, and a week later had progressed only about 20 feet. The interstate crossing is 329 feet wide. “It’s going pretty slowly because they’re in solid rock,” Bond said on Nov. 17.
The project is expected to be completed late this year or early next year, according to Bond.
In a request to FERC filed Oct. 13, Mountain Valley said it needed to work 24-7 in order to “improve feasibility/constructability of the crossing of Interstate 81 and reduce the risk of bore collapse.”
Such a risk exists with any construction-related boring project, “and one measure MVP can take to reduce this risk is to bore continuously,” Mountain Valley spokeswoman Natalie Cox wrote in an email.
Drilling has already been completed successfully under many of the primary and secondary roads that the pipeline must cross on its 303-mile path from northern West Virginia, through the New River and Roanoke valleys, to connect with an existing pipeline near the North Carolina line.
Mountain Valley completed crossings of U.S. 221 and the Blue Ridge Parkway in the Bent Mountain area in 2018, before legal challenges began to delay work on the $7.2 billion project.
Construction resumed this summer after Congress passed a law fast-tracking the completion of the pipeline, which it said will serve a national interest by increasing the country’s energy supply.
VDOT has issued permits for the pipeline to pass under about 60 state-maintained roads in the counties of Giles, Craig, Montgomery, Roanoke, Franklin, and Pittsylvania.
Boring generally entails digging two pits on either side of a road. Drilling equipment is then placed in one of the pits, and a channel for the pipeline is then bored horizontally across to the other pit. A similar method is being used to cross some of the streams and wetlands along the buried pipeline’s route.
For the I-81 project, construction crews will install vinyl blankets or plywood around water pumps to reduce noise. The steps are required to bring nighttime noise levels below FERC-imposed limits for the closest two homes, which are 1,200 and 675 feet away.
FERC is also requiring the use of lighting that shines downward.
Construction of the controversial project has been repeatedly delayed by lawsuits from environmental and community groups, who say that running a 42-inch diameter pipe across steep slopes and through clear-running streams will do serious harm to the region’s natural resources.
Mountain Valley hopes to complete most major construction by year’s end. Final work, including testing and commissioning, will be done early next year. The company says the pipeline will begin to transport natural gas to East Coast markets by late March.