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Published November 01, 2013, 12:48 PM

Tesoro Logistics restarts pipeline shut down by oil spill

Tesoro Logistics has restarted the oil pipeline that was shut down Sept. 29 because of a massive spill in western North Dakota’s Mountrail County, a company spokeswoman says.

By: Forum News Service ,

TIOGA, N.D. — Tesoro Logistics has restarted the oil pipeline that was shut down Sept. 29 because of a massive spill in western North Dakota’s Mountrail County, a company spokeswoman says.

The San Antonio-based company received permission to restart the line after accepting a safety order Oct. 31 from the federal Pipeline and Hazardous Materials Safety Administration and after PHMSA approved the company’s detailed restart plan. Company spokeswoman Elizabeth Watters says oil should begin moving through the pipeline today.

The damaged section of pipeline that leaked an estimated 20,000 barrels of Bakken crude into a wheat field near Tioga was sent to an independent lab for analysis. The preliminary report indicated that the likely cause of the quarter-inch-diameter hole in the pipeline was a strong electrical discharge.

A PHMSA spokesman says the hole may have been caused by a lightning strike, though Tesoro Logistics says the source of the electrical current remains under investigation.

The initial lab report found no signs of corrosion — which initially was cited by a state inspector as a possible cause — or other defects at the point of the leak, the company says.

To ensure integrity before restarting the line, Tesoro Logistics says it performed a pressure test on the 35-mile section of pipeline from Tioga to a rail facility at Columbus, near the Canadian border. It also conducted investigations at six locations on the pipeline to address possible weak spots identified in a Sept. 10 and 11 inspection by an inline tool commonly known as a “smart pig,” but found no areas of concern.

Additional monitoring equipment has been installed along the entire 35-mile segment to detect potential leaks, according to the company.

As of Oct. 31, more than 4,500 of the estimated 20,000 barrels of oil released had been recovered from the field where a farmer harvesting wheat first discovered the spill, Tesoro Logistics reports. The company has estimated cleanup costs at $4 million.

The safety order issued by PHMSA requires Tesoro Logistics to conduct aerial patrols of the pipeline during the restart process and for three days after, and then weekly for one year. Ground patrols also must be done for the first three days and then for 30 days after the restart or until leak detection equipment has established final thresholds. Leak detection equipment should be completed within 12 months, the order states.

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