Thing of the past: Chunk of ice 30 miles long, 12 miles wide, and up to 82 feet thick causes Shell to halt Arctic oil drilling

APNEWSBREAK: Shell halts Chukchi Sea drilling - seattlepi.com

"As a precautionary measure and in accordance with our approved Chukchi Sea Ice Management Plan, Shell has made the decision to temporarily move off the Burger-A well to avoid potentially encroaching sea ice," he said by email. "Once the ice moves on, the Noble Discoverer will re-connect to anchors and continue drilling."

Shell officials on Sunday were monitoring ice measuring 30 miles long and 12 miles wide about 105 miles away from the drill ship, Smith said by phone.

"We're using satellite images, we're using radar images, we're also using onsite reconnaissance to watch this ice so there are no surprises," Smith said.

The ice varies in thickness, he said, but at its thickest is 25 meters, or about 82 feet. It was moving at .5 knots, or .575 mph.