Alyeska Pipeline Services Co. says it is on track to have the trans-Alaska oil pipeline up and running by noon today, a company spokeswoman said.
Cleanup of the oil spill was under way Thursday with about 140 barrels of the oil collected by 4:30 p.m., said the Alaska Department of Environmental Conservation.
Up to several thousand barrels of oil is estimated to have overflowed Tuesday morning from a holding tank into a bermed containment field after a valve opened. The incident was at the last pump station of the pipeline, Pump Station 9, near Delta Junction.
The exact cause of what went wrong is under investigation by state and federal authorities. Damon Hill, of the federal Pipeline and Hazardous Materials Safety Administration, said the agency will specifically examine what happened with the valves, whether or not there was a system in place to prevent the spill from happening, and if there were employees around to do the manual shutoffs.
Alyeska spokeswoman Michelle Egan said the company is also investigating.
"The regulators are certainly talking to our folks and we are making that happen, we are facilitating," she said. "We want to know what occurred and why because if we need to apply some knowledge across the rest of our system, then we are going to do that."
The shutdown has severely curtailed North Slope oil deliveries. The pipeline carries about 650,000 barrels a day of crude oil, about 10 percent of U.S. production. Turning off the pipeline disrupts about $45 million a day of North Slope production and about $13 million a day in state revenue.
Alyeska restored power to Pump Station 9 late Wednesday. Then workers began installing a "pump-around-skid" to pump oil away from the damaged tank that overflowed and was continuing to leak oil. By Thursday afternoon, Egan said the company had successfully withdrawn enough oil to relieve the pressure in the tank and stop any further leakage. A more powerful permanently installed pump will eventually be used to bring the rest of the oil back into the pipeline, she said.
Also on Thursday, Alyeska crews began vacuuming the spilled oil from where it pooled on the ground. They loaded it onto trucks, using machines to suck it out through open drains in the area, Egan said. That oil will be put back into the pipeline at Pump Station 9 or it will be trucked to Valdez and injected there.
If the total of the spill is several thousand barrels, it would be one of the worst in the 33-year history of the pipeline. The oil did not escape the pump station secondary containment area, the state said.
Alyeska and the pipeline are owned by an oil-company consortium led by BP.
Restart of the pipeline can take from one to four hours, Egan said.
Find Megan Holland online at adn.com/contact/mholland or call 257-4343. Reporter Elizabeth Bluemink contributed to this story.