SEATTLE (AP) - A Washington Transportation Department spokeswoman says workers have begun a close-up inspection of the cutter face of a giant machine that got stuck 60 feet underground while digging a highway tunnel under downtown Seattle.
Spokeswoman Laura Newborn says the inspection started late Friday afternoon and work will continue this weekend. The Seattle Times reports (https://is.gd/A4e6af ) that teams of five to six people will clean and examine the cutter in three-hour shifts, working in air at 1.4 times atmospheric pressure. Then they will spend an hour in a tank aboard the tunnel drill, to gradually decompress to normal pressure.
Drilling was halted Dec. 6 by a blockage. Since then, crews have pumped water away from the surrounding soil and sprayed in a clay slurry to help form a crust so compressed air could be pumped in, providing a gap where workers can inspect the cutter.
The state has said that a buried steel pipe is only partly to blame for the stoppage. An independent expert told state senators that the workers’ inspections should solve the mystery.
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Information from: The Seattle Times, https://www.seattletimes.com
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