May 25 (Reuters) - * An administrative law judge for the Pennsylvania Public Utility Commission (PUC) granted a request to stop construction on Energy Transfer Partner LP's (ETP) Mariner East 2 and 2X pipelines and halt flows on the existing Mariner East 1 natural gas liquids pipe.
* Katie Bays, an energy analyst at Height Securities in Washington, said in a note on Friday that "there's a chance the PUC reverses the ALJ order and allows service on Mariner East 1 to resume" at any time following ETP's appeal. ALJ is an abbreviation for "administrative law judge."
* The judge's order, issued on May 21 but not made public until Thursday, applies only to West Whiteland Township, where a sinkhole discovered earlier this year led the PUC to halt service on Mariner East 1 from March 7-May 3.
* The judge granted the request to halt work and flows on the pipelines so additional studies can be conducted on the geology in West Whiteland Township, which is about 30 miles (50 km) west of Philadelphia.
* ETP had already held up work in the area around the township so it could get a permit modification due to the sinkhole problem.
* Officials at ETP were not immediately available for comment.
* The earlier shutdown of Mariner East 1 forced shippers, including U.S. gas producers Range Resources Corp and Antero Resources Corp, to find another route for their liquids, according to analysts.
* Mariner East 1, which started service in the 1930s transporting refined products from the Philadelphia area to western Pennsylvania, was repurposed and expanded to transport propane in 2014 and ethane in 2016 from the Marcellus and Utica shale fields in western Pennsylvania to customers in the state and elsewhere, including international exports from ETP's Marcus Hook complex near Philadelphia.
* ETP has said it expects to complete construction on the $2.5 billion Mariner East 2 pipeline in the third quarter. Mariner East 2 will boost total capacity of the Mariner East project from 70,000 barrels per day (bpd) to 345,000 bpd and open the pipe to suppliers in Ohio and West Virginia.
* At the same time ETP is building Mariner East 2, it is also working on Mariner East 2X, which will add another 250,000 barrels to the Mariner East project. ETP has said it expects to complete Mariner East 2X by the middle of 2019.
Reporting by Scott DiSavino; editing by Jonathan Oatis