Damaged tunnel boring machine stalls Brightwater sewage treatment plant in Seattle

The Brightwater sewage treatment plant is now certain to cross the estimated project cost of $1.8 billion. The project has come to a grinding halt as project experts are unable to decide how to connect two tunnels of different diameters, one of which has a damaged tunnel boring machine (TBM) stuck in it. The damaged machine has been idled near the Lake Forest Park for more than a year now. Vinci/Parsons/Frontier-Kemper had brought two TBMs to the site, both of which was damaged after a few months in operation. The TBMs were subsequently shutdown in May 2009. One of the TBMs was repaired and it successfully completed excavation from Kenmore to Bothwell in June 2010. But the second machine has been idled at the site since then. The Vinci/ Pasons combine has been taken off and replaced by Jaydee/ Coluccio to complete the job. The county is now trying to figure out if they should dismantle and remove the tunnel boring machine or tunnel around it.