Highway 99 tunnel-machine update: Component testing under way; still hoping for pre-Christmas tunneling

The state is circulating an update on the Highway 99 tunnel project this afternoon, saying some components are being tested, and the contractor is still working toward restarting tunneling right before Christmas:

Seattle Tunnel Partners and manufacturer Hitachi Zosen have begun testing components of the SR 99 tunneling machine as they prepare to resume mining. A few initial tests were performed last week, and several others are slated to occur in the coming weeks.

This week’s highlights include tests of various pumps inside the machine, as well as the screw conveyor system that carries excavated material from the cutterhead to the back of the machine and out of the tunnel. All of the tests are being conducted by STP and Hitachi, who are jointly responsible for ensuring the machine is ready to complete the remainder of the tunnel drive. Future tests will include rotation of the machine’s cutterhead, which, according to STP, will occur in late November.

Some reassembly work is ongoing. Major components of the machine are in place, but crews continue to weld pieces together and reconnect wires and hoses. STP’s most recent schedule shows that the machine will be ready to resume mining on Dec. 23. WSDOT cannot verify the contractor’s schedule. This narrated video explains STP’s repair effort in more detail.

Other work

STP crews have finished treating the ground north of the access pit. They began injecting grout into the soil there last month to stabilize the area where the machine will exit the access pit. Crews will soon place a thin layer of sand at the bottom of the pit; the rest of the pit will be filled after initial testing is complete.

STP crews are also preparing to install glass walls at the operations buildings located at each portal. The north building’s glass will be installed first. Read more about those efforts in this post.

The machine stopped tunneling in December 2013.

8 Replies to "Highway 99 tunnel-machine update: Component testing under way; still hoping for pre-Christmas tunneling"

  • JanS November 13, 2015 (12:12 am)

    pre-Christmas? Seeing is believing…

  • Rick November 13, 2015 (1:18 am)

    Just in time for the holiday break.

  • Smitty November 13, 2015 (2:36 am)

    “Mining”? Have they been using that term all the time or is that new? Sounds like a legal change of some sort……

  • Smitty November 13, 2015 (7:01 am)


  • LarryB November 13, 2015 (11:32 am)

    Can’t we just stop throwing good money after bad?
    We’d get a lot more bang for the buck if the same amount of money went towards more light rail. Sound Transit’s contractors know how to use a boring machine, unlike STP’s clowns.

    Yeah – I know. The money can’t be moved because our state/city is absurd.

  • Felix November 13, 2015 (12:00 pm)

    LarryB….Yeah, I don’t know how you can stand to live here, you should probably move, it’s only going to get worse for you.

  • Doug F November 14, 2015 (7:17 pm)

    Time to use common sense and stop the project. This is a loser to be sure. More delays for sure but please keep the checks coming.

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