SEATTLE — An environmental review has been completed and the contractor trying to burrow a highway tunnel under downtown Seattle plans to start digging a pit in July to reach its stalled boring machine.
The pit will be 120 feet deep and about 80 feet in diameter. After it’s completed in September, workers plan to lift out the head of the machine to repair seals and bearings.
The machine dubbed Bertha ground to a halt in early December about 1,000 feet into the 1.7-mile Highway 99 tunnel that will replace the Alaskan Way Viaduct.
Bertha is expected to resume boring again in March 2015, and the contractor, Seattle Tunnel Partners, hopes to have the tunnel open in November 2016.