Bertha to resume digging Seattle tunnel Monday

SEATTLE (AP) — Seattle's broken down tunnel boring machine should get back to work Monday after a pipe stopped progress on a new State Route 99 more than two years ago.

Chris Dixon of Seattle Tunnel Partners told state lawmakers on Thursday that Bertha only needs to advance through the sand and dirt inside the machine's repair put before the dig resumes in earnest in January.

After the machine advances through 450 feet to a previously fortified area, the next step will be to tunnel beneath the Alaskan Way Viaduct.

The Washington State Department of Transportation expects to close the viaduct to traffic for up to two weeks when Bertha drills beneath it.

The four-lane toll tunnel Bertha is working on was supposed to open at the end of 2015.