Feb. 10 update: Accessing the seal system inside the tunneling machine

Posted on Feb 10 2014 8:29 PM

This evening Seattle Tunnel Partners (STP) informed WSDOT and responded to a media inquiry that it is still conferring with its experts to determine how to repair or replace the broken seals surrounding the main bearing of the SR 99 tunneling machine.

Replacing the seals is a complicated process and STP is working closely with Hitachi Zosen, the tunneling machine’s manufacturer, to determine the best path forward. They are looking at two ways to access the seal area: through the back of the machine or by drilling an access shaft from the surface in front of the machine. Either way, this process will take months. They expect to make a decision by the end of the week, and once they do, we will share that information with the public.

STP has not yet fully determined the cause of the seal problems and to date, they have not shown any evidence that suggests the state or taxpayers will be responsible for cost overruns associated with these repairs. We have requested and expect detailed plans on how the repairs will be made and how STP can recover lost time on the tunneling project.

Since the machine is stopped and repairs need to be made, STP has also informed the City of Seattle that they can proceed with seawall replacement construction near the machine’s current location.

Previous updates

Feb. 7, 2014 update – Two factors contributed to tunnel stoppage

Jan. 31, 2014 update – Further evaluation required before tunneling can resume

Jan. 28, 2014 update – SR 99 tunneling machine inches forward

Jan. 27, 2014 update – Restart of tunneling machine begins this week; evaluation will follow initial mining

Jan. 23, 2014 update – Hyperbaric investigations continue