After months of pleading from Energy Transfer Partners LP’s (ETP) Rover Pipeline LLC, FERC has lifted a moratorium on horizontal directional drilling (HDD) that had delayed portions of the 710-mile, 3.25 Bcf/d natural gas mega-project.

In a letter order issued late Monday, the Federal Energy Regulatory Commission authorized Rover to resume HDD activities at nine sites where work had been suspended following a roughly 2 million gallon drilling fluids spill near the Tuscarawas River in Stark County, OH, earlier this year.

“Rover has demonstrated sufficient progress on the required rehabilitation and restoration of the areas affected by the inadvertent release and drilling mud contamination,” FERC wrote. “Rover has also developed and filed specific measures to address the recommendations” made by J.D. Hair & Associates Inc. following an independent review “as well as staff’s site-specific recommendations for the referenced nine crossings.”

The list of sites includes the Captina Creek HDD, identified as a key crossing point for the Clarington Lateral in eastern Ohio, part of Rover’s Phase 1B. ETP management has said it will take about 40 days to complete the Captina HDD.

The other sites where HDD work can resume include:

In the months following FERC’s order halting new HDD work, Rover sent multiple requests to reauthorize HDDs. The company also hired an independent HDD specialist to provide analysis and recommendations.

FERC said Monday that it’s still investigating the Tuscarawas spill over the presence of diesel fuel in the drilling mud.

“This authorization for Rover to re-commence certain HDD activities does not bear on or impact” the Office of Enforcement’s “ongoing investigation into the circumstances of the drilling fluid contamination at the Tuscarawas River HDD site, and the causes thereof,” FERC wrote. FERC said any deviation from approved plans developed in response to the spill could result in a stop-work order for Rover or additional referrals to the Office of Enforcement.

Lifting Rover’s HDD moratorium counts as a significant win for the producers that have staked claims on the pipeline’s substantial transportation capacity out of the Appalachian Basin. Rover, which started flowing earlier this month, is designed to deliver Marcellus and Utica shale gas to markets in the Midwest, Gulf Coast and Canada, including via interconnects with the Midwest Hub in Defiance, OH, and the Vector Pipeline in Michigan.

ETP plans to finish construction on Rover by the fourth quarter.