SEATTLE — Seattle’s massive tunneling operation is on hold yet again due to ongoing problems with the world’s largest boring machine.
After a seven-week stoppage, crews restarted the tunneling machine earlier this week and moved it forward about two feet. Washington state’s Department of Transportation said Friday that the machinery showed above-normal temperature readings when that movement occurred.
Those same above-normal temperature readings were occurring when crews decided to stop mining in early December.
State transportation officials say they will be working with outside tunneling experts to review the situation and determine the best path forward.
The machine named “Bertha” is only one-tenth of the way toward completing a 1.7-mile tunnel. The tunnel will carry Highway 99 traffic and allow the removal of the aging Alaskan Way Viaduct along the Seattle waterfront.