Why TransCanada Drilled Under the Potomac River

Earlier this month, TransCanada took a barge across the C&O Canal to the Hancock Boat House, took the barge up river about a mile and a half and drilled a hole under the Potomac River.



TransCanada is proposing to construct a new interstate natural gas transmission pipeline that will cross under the Potomac River and the historic C&O Canal.

TransCanada has applied to the National Park Service for a permit to survey the region, but has yet to receive the go ahead on that permit.

The company did however get permission from the Maryland Department of the Environment and the Army Corps of Engineers to conduct a test bore under the Potomac River.

That test was completed in one day on January 17.

According to a permit application made to the U.S. Corps of Engineers and Maryland Department of the Environment, on that day, TransCanada engaged in “geotechnical testing within the Potomac River to determine if the geology is favorable to cross the river using horizontal drilling technology.”

A barge was launched from the Hancock Boat House and motored upstream to the site of the proposed pipeline.

According to the permit application, “a bore will be conducted within an enclosed contained area to ensure sediment or drilling mud is not released into the river during the testing.”

“This will be accomplished through installing a casing around the bore location that will be dewatered prior to the starting of the boring,” the permit said. “All water removed from the casing during dewatering, sediment from the bore and any drilling mud will be captured and taken offsite for disposal to ensure that nothing is released into the river.”

The application says that “rotary drilling will be performed until rock is encountered.”

“Once rock is encountered, mud rotary drilling will cease and rock core drilling will begin. The rock coring process involves inserting a 2” NQ double barrel into the outer casing and directly into rock. The NQ double barrel allows for the rock core to be pulled to the surface and maintain an open bore hole for further coring.”

The application says that the bore hole will be “grouted upon completion.”

TransCanada is planning an open house to discuss its plans for the pipeline February 9 at 6 pm at the Hancock Town Hall.

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