Once again drilling work to install Sunoco’s Mariner East 2 Pipeline in Middlefield Township in Delaware County, PA (near Philadelphia) has resulted in a sinkhole. This one is about the size of a 15×15 swimming pool. Sunoco reports the hole exposed a 12-inch pipeline flowing NGLs (no holes, no leaks in the pipeline). The company immediately filled in the sinkhole and covered over the NGL pipeline.