Investigators with the Pennsylvania Public Utility Commission are looking into a new sinkhole along the route of Sunoco Pipeline LP's Mariner East NGL pipeline system.
The roughly swimming-pool-sized subsidence was in Middletown Township in Delaware County, near the eastern terminus of the Mariner East family of NGL pipelines. First reported to the commission on Sept. 13, the sinkhole did not affect the integrity or operation of the 12-inch steel pipe of the GRE Line that was exposed, according to both the Energy Transfer LP affiliate and the commission, also known as the PUC.
"Under the guidance of a professional geologist who was onsite, the area was secured, filled in and the pipe, covered," Energy Transfer spokeswoman Amanda Gorgueiro said in a statement. "There was no risk to the surrounding community as the length of the exposure was well within the maximum allowable span length for exposed pipe."
No leaks or injuries were reported in the incident, the PUC said.
The 345,000-barrel-per-day Mariner East family of NGL pipelines share the same route through the suburban Philadelphia counties of Chester and Delaware before arriving at the Marcus Hook terminal on the Delaware River. At the terminal, ethane, butane and propane would transfer to ships and railcars for transportation to downstream users, such as European plastics manufacturers. Several Appalachian shale gas drillers, notably Antero Resources Corp. and anchor shipper Range Resources Corp., are hoping for better prices overseas than they receive in the United States' major NGL market, the Texas Gulf Coast.
One of the pipelines, Mariner East 1, was shut down for three months earlier in the year after a sinkhole was found in a community in Chester County.
"The political situation around ME2/2X remains volatile," pipeline analysts at Height Securities said April 26, but Energy Transfer seems to be solving problems one issue at a time and should open the Mariner East 2 family by the end of this year. "Sinkholes remain an unpredictable threat, though they typically only grab headlines and don't constitute a real operational risk," Height said.

