An eruption of Redoubt volcano Thursday morning triggered a flood of mud-choked water in the Drift River, but officials were at a loss to say whether it passed harmlessly by the oil facility near the mouth of the river or penetrated the protective dike there.
Rod Ficken, vice president of Cook Inlet Pipeline Co., said remote monitoring equipment on two tanks that each contain 3 million gallons of crude oil showed no change in their level, strong evidence that they remain intact.
But until observers can fly over the Drift River oil terminal and report back, no one will know how high the river reached and whether water and mud got into the tank farm, Ficken said. The facility has no remote video or flood sensing equipment, he said.
The terminal was evacuated Monday morning early in the series of eruptions that have periodically swollen the river and threatened the facility.
Two aircraft chartered by the Alaska Volcano Observatory -- a helicopter and airplane -- were still in the air Thursday evening. Officials on the ground didn't know if they were able to make detailed observations over the Drift River terminal, and results will probably not be reported till today.
An eruption-triggered flood early Monday safely swept past the oil storage area, though some muddy water appeared to have lapped over a protective dike. A deposit of deep mud emerged on the nearby airstrip when the river receded.
Ficken said the engineer who designed the dike during Redoubt's last eruption cycle in 1989-1990, Jim Aldrich, paid a visit to the site Thursday morning by helicopter. He and 10 others had to abandon the area quickly around 9:30 a.m. when the eruption started and the aviation safety code went from orange to red, Ficken said, but Aldrich was satisfied that Monday's flood didn't damage the concrete-clad earthen dike.
"He felt comfortable that it did its job," Ficken said. "He feels right now, at this time, that the integrity is good."
But Aldrich still wants to take a more detailed look at the site. And if floodwaters reached the dike Thursday, that would be all the more reason for further inspection, Ficken said.
Thursday's eruption began at 9:24 a.m. without the warning swarms of earthquakes that marked eruptions earlier this week, Alaska Volcano Observatory geophysicist Stephanie Prejean said at an afternoon press conference. That's to be expected at this stage in the eruption cycle, she said, because lava has plumbed a clear path to the surface and is no longer fracturing the rock in its path. But it also means that a code-red alert signaling an active eruption can occur at a moment's notice.
Seismographic data gave strong indication that a muddy flow had started down the Drift River spurred by melting ice and snow, she said.
In an interview, Ficken said it takes an average of four hours for a flood to reach the Chevron-operated facility, more than 20 miles away.
Sara Francis, a Coast Guard spokeswoman, said at the press conference that officials were planning to begin sounding operations at Christy Lee platform, the offshore oil-loading facility for the Drift River terminal. A tanker had been due to arrive in early April to haul oil to the Tesoro refinery in Nikiski, and officials wanted to ensure that sediment from Monday's flood hadn't made loading operations dangerous, Francis said.
If the tanker can safely dock, it might be used to reduce the amount of oil at the facility, Francis said. It's also possible that normal operations at Drift River could resume and that a larger load could be hauled out, she said. What happens will depend on conditions, she said.
The Drift River terminal, built in the 1960s, is an important waypoint in the delivery of oil produced from Cook Inlet platforms operated by Chevron and other companies. Oil is pumped from the platforms in underwater pipes to facilities at Trading Bay and Granite Point, where initial processing occurs.
From there, according to Santana Gonzalez, a spokesman for the Chevron Pipe Line Co., it travels by pipeline to Drift River where it is stored in the tank farm until it is taken onboard a tanker.
Drift River has seven standing tanks, each with an 11-million-gallon capacity. With the decline of the Cook Inlet fields, three of the tanks have been decommissioned and two others are kept empty but on standby.
Earlier this week, the environmental organization Cook Inletkeeper said the two operational tanks should be immediately drained to avoid a catastrophic spill if floodwaters breached the dike.
But Ficken, the pipeline company official, said it's riskier to completely drain the tanks than to leave oil at what operators call the "working level" of a tank -- in this case, about 1.7 million gallons, or a little more than half of what's in each one now.
Preserving oil at the working level, calculated from the tank's size, weight and shape as well as the density of the oil in relation to water, gives the tank greater stability and reduces its buoyancy, he said. That, in turn, makes it less likely it would float off its foundation in a severe flood, which would destroy its usefulness and risk a rupture that would leak residual hydrocarbons into the environment.
Ficken said he isn't worried about the two standby tanks. They won't float because they've been opened, and they've been cleaned, he said.
Ficken estimated that Granite Point, Trading Bay and the platforms themselves have a little less than two weeks of storage capacity before they have to slow or stop production if oil can't be moved to Drift River.
Find Richard Mauer online at adn.com/contact/rmauer or call 257-4345.