Mariner East 2
Project Modification
HDD 400 West Whiteland Township, Chester County

Sunoco Pipeline, a subsidiary of Energy Transfer, received approval from the Pennsylvania Department of Environmental Protection for a change to the route and installation method for a portion of the 20-inch pipeline located in West Whiteland Township, Chester County. The 16-inch pipeline has already been installed.

The company changed from a horizontal directional drill (HDD) to a combination of open cut installation and direct pipe installation on two sections of the route near the Exton Bypass and Lisa Drive in West Whiteland Township. See below for a map of the route.

The modification includes the following components:

  • Direct pipe bore measuring approximately 820 feet to go under the Exton Bypass (State Route 30), Amtrak and Norfolk Southern Railroad, about 0.5 miles east of North Pottstown Pike (State Route 100)
  • Open cut installation spanning approximately 1,250 feet near Lisa Drive

The change in construction methodology will minimize the potential for inadvertent returns or a reoccurrence of subsidence and will shorten the time that construction is inconveniencing the local community to an estimated four months — excluding site preparation and restoration — versus the general estimated frame of more than one year for HDD installation.

NOTE: Construction methods, completion times and exact locations are subject to change due to the inherent fluidity of the construction process and outside factors.


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Our goal is safe, time-efficient pipeline installation

The approved change to the construction method caters to the local geology, maximizing safety and efficiency for the installation of the Mariner East 2 and 2X pipelines. The end result is the completion of active construction in a fraction of the original time frame. By using the most advanced safety technology and monitoring systems, as well as teams of experienced contractors, construction can be performed safely with less disruption to your community.

In order to proceed with the new construction methods — which will maximize safety and efficiency — the Pennsylvania Department of Environmental Protection (DEP) approved major modifications to the existing permits.

What Is a Major Modification?

This is classified as “major modifications,” which is a change to an existing environmental permit issued for pipeline construction that exceeds a minor revision. It could be a change in the construction method, the specific pipeline route or the workspace within the right-of-way. In the case of Mariner East 2, such environmental permits are issued by the Pennsylvania DEP.

Installation Methods

The requested major modifications will be a change from Horizontal Directional Drill (HDD) to a combination of open cut, conventional bore and/or direct pipe installation methods.

Open cut installation is a straightforward and traditional method, where workspace is available. Open cut is commonly used for construction, repair and replacement of various utilities, such as pipelines and sewer and water lines. The pipeline is lowered into a dug trench, followed by backfilling of the subsoil and separated subsoil, where applicable.

Direct pipe installation is a combination of HDD and tunneling for all soil conditions. A thruster and a steerable microtunneling machine install steel pipes in one continuous pass. The direct pipe bore method uses significantly less bentonite than other trenchless methods, dramatically reducing the possibility of inadvertent fluid returns.

For additional information, please check out our fact sheet