SEATTLE (AP) - The Seattle tunnel boring machine known as Bertha is back on a slightly shifted course after additional measurements confirmed it was 6 inches east of the correct site.
The Seattle Times reports (https://goo.gl/LC7l1N ) the drill resumed digging Monday following a stoppage that included three rounds of surveys.
Operators will gradually steer Bertha back on course.
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Seattle Tunnel Partners used the stoppage to replace some of the 600-pound disc-shaped cutter blades.
State transportation officials say tunnel contractors are considering whether to perform additional measurements.
The $2.1 billion downtown-bypass tunnel from Sodo to South Lake Union is expected to open to traffic in early 2019, followed by demolition of the Alaskan Way Viaduct.
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Information from: The Seattle Times, https://www.seattletimes.com
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