Seattle contractors challenge order to halt tunneling

SEATTLE — Seattle contractors say the state’s order to suspend digging a new Highway 99 tunnel is unjustified.

Seattle Tunnel Partners say they had already responded appropriately to a sinkhole problem when Gov. Jay Inslee ordered them to stop tunneling, reported The Seattle Times.

STP manager Chris Dixon sent Inslee and the Washington State Department of Transportation a letter and a root-cause analysis of the sinkhole. Dixon wrote that contractors immediately filled the sinkhole with a mixture of concrete and sand after it formed in the wake of a tunnel-boring machine on Jan. 12.

“Stopping the (tunnel-boring machine) at its current location is not recommended and increases the risk of creating additional sinkholes,” says the contractors’ study. It also says it’s impossible to know for sure what caused the sinkhole.

Independent, state-chosen experts are expected to review the contractors’ findings.

WSDOT is still reviewing the STP documents, according to spokeswoman Laura Newborn.

No date has been announced for the tunneling to resume. STP will need written permission from WSDOT to resume the deep dig.

A clause in STP’s $1.35 billion contract allows the state to suspend tunneling to correct unsafe conditions for the workers of the public.