This morning (Sept. 13, 2019) a sinkhole opened in the Dragonpipe (Mariner East pipeline) easement at Sleighton Park in Delaware County, near the intersection of Valley Road and Forge Road. I understand that the active 12-inch (“workaround”) pipeline was exposed by the sinkhole, but it was subsequently covered with sand. The 12-inch line is a very old pipeline, part of the cobbled-together line that Sunoco is calling “Mariner East 2”. The image above is from drone footage provided by Eric Friedman.
More information is here.