Third Sink Hole Discovered on Mariner East Pipeline 4 Feet Wide & 30 Feet Deep

Another sinkhole develops along Mariner East route in Sleighton Park

From an Article by Bill Rettew, Daily Local News, Chester County, Penna., October 18, 2019

MIDDLETOWN—A third “sinkhole” has opened up along the Mariner East pipeline construction route in Middletown Township in Sleighton Park. A Middletown Township release reads that at 3:30 p.m. Thursday, township staff was contacted by Delaware County emergency services staff regarding a potential “subsidence” at Sleighton Park.

It is believed that an 18-inch hole developed at the site, which was quickly filled in by workers with concrete. It marks the second sinkhole at Sleighton Park, with a third which developed near the state police barracks on US Route 1.

Township staff responded within 15-minutes to discover an 18-inch diameter hole formed north of Forge Road, south of the existing sound barriers, that “may have been from previous potholing completed by Sunoco for the 16-inich pipeline,” reads a township release.

The void was filled with flowable fill by the time township staff who arrived on scene; it was reported that 48 yards of material was used to fill the void.

Nils Hagen-Frederiksen, of the Public Utility Commission, said the uncovered pipeline was active at the time of the repairs but was not necessarily moving product.

The 18-inch hole was the opening of a subsidence that fanned out to approximately 4 feet in width and 30 feet in depth, as it was reported to the township.

The PA-PUC was on site prior to the subsidence being filled to confirm its condition, reads the township report. “The PUC viewed the situation as not an immediate threat, but it is an open and ongoing investigation.” The PA-DEP was also on site and determined the situation was not an immediate threat.

A 12-inch pipe that was likely active was partially exposed within the subsidence or “sinkhole;” It was reported that approximately 18-36 inches of the pipe was exposed and unsupported.

County emergency services staff completed air monitoring for gas at the location of the subsidence and within the immediate surrounding area. Results were negative, reads the township report. Township staff departed the site as the respective agencies did not find any breach in the pipeline(s), no immediate threat was present, the void was filled, and restoration completed at this time.

Del-Chesco United for Pipeline Safety released the following statement on Friday: “Middletown Township has no idea of the extent of the subsurface damage done by Sunoco at Sleighton Park. Middletown’s assertion that “no immediate threat was present” is remarkable, given that this latest sinkhole once again left an ancient pipeline suspended in midair and given that Middletown is without a credible plan to protect the public in harm’s way. It’s unfortunate that Middletown Council itself facilitated this hazard when it chose to sell easements to Sunoco across this public park.”

Mariner East will ferry hundreds of thousands of barrels daily of liquid gases such as ethane, butane, and propane from the Marcellus Shale regions across the full 350-mile width of the state to a facility in Marcus Hook. It crosses 11 miles of western Delaware County and 22 miles through the heart of Chester County.

It has sparked intense community opposition from residents who objected to the routing through densely populated neighborhoods. Residents fear not only loss of property values but also security issues and the lack of a fully developed emergency response in the case of an accident or leak.

The multi-billion dollar project has been plagued by runoffs, sinkholes and work stoppages ordered by the state.