The Washington State Department of Transportation announced Monday night that Bertha, the enormous tunnel boring machine, is expected to resume digging sometime this week.
Bertha ground to a halt Dec. 6 after running into an 8-inch diameter pipe that had been left in the ground in 2002 after the department checked groundwater in the area.
WSDOT officials say inspections will be completed by Tuesday morning, and Bertha will attempt to advance two feet so crews can finish building the next tunnel ring, which was in progress when Bertha stopped moving in December.
Officials don't yet know exactly what happened with the machine and why it has taken so long to resume digging.
"While we understand the interest in knowing the reasons why mining was stopped in December, it will take time to review the results of the hyperbaric interventions and consult with tunneling experts advising WSDOT," according to WSDOT.
Bertha is stopped about 60 feet underground and one-tenth of the way toward completing a 1.7-mile tunnel. It will carry Highway 99 traffic and allow the removal of the Alaskan Way Viaduct.