Jan. 17 update: Crews begin inspecting excavation chamber
This afternoon, crews entered and began inspecting the SR 99 tunneling machine’s excavation chamber. Air is being pumped into the chamber to stabilize the ground in front of the machine so crews can safely work in areas that would otherwise be filled with soil and water. A detailed description of this type of work – known in the tunneling world as a hyperbaric intervention – is included in our Jan. 14 update.
Keeping workers safe is everyone’s top priority. Our contractor, Seattle Tunnel Partners (STP), has a number of safeguards in place to protect crews as they perform their work within the chamber. Working under hyperbaric conditions is difficult, but it’s normal within the tunneling industry and has been done on other projects all over the world.
The goal of STP’s inspection is to learn, definitively, what caused the issues that slowed the machine’s progress. Once they know what's wrong, they can develop a plan to address the issue and resume tunneling. The inspection will likely take several days.