The Washington State Department of Transportation has been concerned about the Seattle tunnel drill Bertha since its launch last July, Secretary of Transportation Lynn Peterson said Wednesday in a letter to lawmakers.
“We have discussed these concerns with STP [Seattle Tunnel Partners] frequently over the past five months and this week sent a formal letter stating our concerns and asking STP how they will address them prior to tunneling under the viaduct and downtown,” Peterson wrote.
The world’s largest drilling machine has been halted since running into an obstruction Dec. 6. Officials are still trying to determine what exactly is blocking Bertha and how to resolve the problem. A steel pipe is believed to be at least part of the cause.
Peterson said she has requested the contractor provide WSDOT with information by the end of the day Wednesday including STP’s plans for making up time lost by the work stoppage. Peterson is also asking why Bertha was operating at extremely high temperatures before the stoppage on Dec. 6, and potential causes of wear to the cutting tools and other parts of the drill.
STP said it was sending a crew of workers to the 57-foot cutting face of the massive machine Wednesday night to inspect for damage and obstructions. The specially trained team of five will be working in compressed air requiring decompression before and after their work, much like divers undergo.
The letter said WSDOT can’t tell STP what to do because the agency could be liable for increased costs and responsibility. Peterson said she was sending the information to lawmakers rather than forwarding the formal letter she sent the contractor because “it could be the subject of a potential future litigation between WSDOT and the contractor.”