With Redoubt volcano signaling that it's slipping back into sleep, oil company officials Monday announced tentative plans to resume crude shipping and production from the west side of Cook Inlet.

Santana Gonzalez, a spokesman for Cook Inlet Pipe Line Co., said officials hope that by mid-August the first tanker load of oil in more than four months will be able to leave the volcano-threatened Drift River Oil Terminal. That would free up storage capacity for 10 idled platforms in Cook Inlet, allowing them to resume oil pumping.

Chevron had to shut in its Cook Inlet oil wells in April when Redoubt forced a halt to terminal operations.

The Drift River terminal is just 22 miles downriver from the volcano. Explosive eruptions in March and April sent dangerous floods of water, mud and huge ice chunks past the terminal tank farm, where two tanks held a combined 6.2 million gallons of crude. A dike around the tanks held back the flood, but conditions were so dangerous that crews couldn't remain on site around the clock and the terminal was shut down.

Normally, Drift River has enough storage to hold about a month's production from the 10 platforms, roughly 315,000 gallons a day, a far cry from their heyday in the 1960s and 1970s. As its tanks begin to reach capacity, a tanker ship is summoned to the Christy Lee platform just offshore at Drift River to take on the crude.

The shutdown of Drift River set off a chain reaction upstream. Some 40 miles north, the onshore storage tanks at Trading Bay and Granite Point reached capacity, about 3.8 million gallons. With no place for the oil to be put, crude production shut down at the 10 platforms.

Roxanne Sinz, a Chevron spokeswoman, said none of the 185 Chevron and Union oil field workers lost their jobs, though some contractors were sent home. Some workers were needed for natural gas production, which wasn't affected by the shutdown, and others were assigned maintenance tasks.

Sinz said engineers don't yet know whether the four-month shutdown will result in a permanent loss of production. That sometimes happens when the flow at a well is temporarily stopped and geologic structures plug up.

In April two ships were able to drain most of the crude at Drift River, reducing the threat of a spill. About 840,000 gallons of oil remains, mixed with a much larger volume of water. Before the tanks can be used again, they will have to be drained into a tanker, probably in early August, and then cleaned, a time-consuming process that will be delayed until next year, said Santana, the Cook Inlet Pipe Line Co. spokesman.

In the meantime, Santana said, engineers and operators have devised a work-around. Oil will be stored in the tanks at Trading Bay and Granite Point. Each time those tanks approach capacity -- probably every two weeks -- the oil will be pumped through a 42-mile pipeline to Drift River. Instead of going into tanks there, it will be pumped directly to a ship docked at the Christy Lee platform in a 28-hour marathon pumping session.

Operations can't begin until mid-August, Santana said. Pumps have to be beefed up to increase the pipeline capacity and new valves and other fittings are necessary. The company will also need approval from state and federal regulators, he said.

Betty Schorr, a program manager with the Alaska Department of Environmental Conservation, said she will be meeting with company officials today to hear the plans. If the changes to their operations pose new, significant environmental risks, it would trigger a 30-day public review process before the plans can be approved. If not, the state could simply allow the revisions.

And the volcano? Scientists with the Alaska Volcano Observatory have reduced the watch level, though it's not yet at code green. They warn it is still possible for Redoubt's fresh lava dome to undergo an explosive collapse and send a flood down the Drift River, though that likelihood lessens with each passing day. The scientists are no longer staffing their operations center around the clock, though automated e-mail alarms would alert them to an emergency.