

(August 31st photo by Vlad Oustimovitch)

WSDOT announced this afternoon that the Highway 99 tunneling machine is back on the move after a two-week stop to change cutterhead tools. Above is a photo of a used “tooth,” taken by Vlad Oustimovitch, a West Seattle resident who is a longtime member of the citizens’ advisory group and shared photos with WSB after a tour of the machine toward the start of the stopdown. Today’s WSDOT update says that as of lunchtime, “crews were tunneling north approximately 170 feet below First Avenue, just north of Union Street” and that the contractor “replaced a total of 14 large cutting tools during the two-week maintenance period. Bertha has moved from clay to a mixture of sand and gravel that wears down cutting tools more quickly. … The tools STP changed during this maintenance stop are the first parts of the cutterhead that contact the ground, making them crucial to the machine’s ability to excavate soil. STP will continue to inspect and replace these tools as needed during the course of mining. … The machine has tunneled more than 4,135 feet and is nearing the halfway point of its 9,270-foot-long journey.”