Crews ready to hoist and repair massive tunneling machine under Seattle

SEATTLE (Reuters) - The world's largest tunnel-boring machine, stuck for over a year underneath downtown Seattle, will be pulled above ground starting this week to be repaired, state officials said on Tuesday. The machine, known as Bertha, stopped working in December 2013 after digging just 10 percent of a planned tunnel to replace an aging waterfront highway, stalling a $3.1 billion project. Seattle Tunnel Partners, the contractor on the project, said earlier this month it hopes to have Bertha drilling again by August. The new timeline for replacing the busy Alaskan Way Viaduct, damaged in a 2001 earthquake and nearing the end of its lifespan, is now 2017. The 2,000-ton tool had to be partially dismantled before it can be hoisted from its pit by a massive crane specially made to hold its girth, the Washington State Department of Transportation said in an update on Tuesday about the rescue efforts. "Crews may lift the first of four pieces of the machine's front end to the surface as soon as this week," a statement said. Repairs on the machine will take place just to the side of the waterfront highway hugging downtown Seattle that the tunnel will eventually replace. Bertha's breakdown and other unexpected construction issues have left the project two years behind schedule and sparked concern about massive cost overruns. The project had initially been slated to cost $2 billion and to be completed by 2015. (Reporting by Victoria Cavaliere in Seattle; Editing by Dan Whitcomb and Sandra Maler)