Underground horizontal directional drilling (HDD) work done by Sunoco Logisitics Partners in Chester County to install the twin Mariner East 2 (ME2) pipelines has led to the development of three large sinkholes (see 3rd Sinkhole Appears Near ME2 Construction in Chester County, PA). The third sinkhole that developed exposed a portion of the existing Mariner East 1 pipeline, causing ME1 to be closed until further notice (see PA PUC Shuts Down Mariner 1 Pipeline Due to Mariner 2 Sinkhole). In order for ME1 to reopen, the state Public Utility Commission has to be assured further drilling for ME2 won’t further disturb ME1. The problem is that the underground geology in that area of Chester County is known as a karst–analogous to Swiss cheese rock layers underground. Not conducive to HDD work. So Sunoco is changing gears. The company has filed a request with the Dept. of Environmental Protection (which oversees the regulation of the project) to change from using HDD to instead using a couple of alternative methods to get the pipe in the ground–including trenching. Before the DEP gives its OK, they will first hold a public hearing on April 30th in West Chester…
