SEATTLE (Reuters) - The world's largest-diameter tunneling machine could resume drilling under downtown Seattle in late November after repairs are completed, allowing a central part of a years-delayed highway project to go forward, Washington state officials said on Friday.
The broken machine, known as Bertha, stopped working in December 2013 after digging just 10 percent of a planned tunnel to replace an aging waterfront highway. It was stuck for more than a year underneath downtown Seattle.
The new timeline for replacing the busy Alaskan Way Viaduct and opening it to drivers is now spring 2018, Washington state Department of Transportation said in a statement. The viaduct was damaged in a 2001 earthquake and is nearing the end of its lifespan.
"Tunneling is slated to resume in late November, with the machine emerging at the north end of downtown approximately one year later," the Transportation Department said. "The state is not able to verify the contractor's schedule."
Previously, project contractor Seattle Tunnel Partners said it hoped to have Bertha drilling again by August, but it pushed that estimate by nearly four months to Nov. 23, according to a timeline provided to the state.
In March, crews hoisted Bertha's 2,000-ton front end from a pit in an attempt to assess damages and make repairs and improvements, which are scheduled to wrap up in the fall.
Bertha's breakdown and other unexpected construction issues have left the $3.1 billion project two years behind schedule and sparked concern about even greater cost overruns. The project had initially been slated to cost $2 billion and be completed by 2015.
Reporting by Eric M. Johnson; Editing by Eric Beech