The Pennsylvania Department of Environmental Protection (DEP) has fined Stonehenge Appalachia LLC $1.5 million for a series of unauthorized sediment discharges and a landslide it caused in Western Pennsylvania during the construction of a natural gas gathering system there.

The company, an affiliate of Colorado-based Stonehenge Energy Resources LP, has signed a consent order and agreement, accepting responsibility for the incidents, said Acting DEP Secretary Patrick McDonnell. The violations took place between November 2015 and March 2016. Stonehenge has been working on restoration and mitigation activities.

DEP issued the company and its contractors a cease and desist order in March for violating environmental regulations and various stream and wetland crossings along an 18-mile pipeline in Butler County. The agency said it determined that Stonehenge caused “uncontrolled and unpermitted” discharges of sediment into a stream, filled two wetlands with sediment and caused a landslide into a stream.

The company’s boring work, DEP said, also discharged significant amounts of drilling fluids, including bentonite clay, into state waters. Stonehenge had appealed the cease and desist order, but will withdraw its appeal as part of the consent order.

Stonehenge operates in the Rockies and Appalachia. In 2015, it agreed to construct a 400 MMcf/d gathering system for Rex Energy Corp.’s Moraine East acreage in northern Butler County (see Shale Daily, June 4, 2015). That system collects natural gas for delivery to MarkWest Energy Partners LP’s Bluestone processing facility in southwestern Butler County.

In February, DEP inspectors observed a landslide near a compressor station that’s owned by the MarkWest facility. The fine was assessed for violating the state’s Oil and Gas Act, Clean Stream Law, Dam Safety and Encroachments Act and the Solid Waste Management Act.