The giant Highway 99 tunnel drill has paused this week for maintenance and repairs below King Street, after grinding about 430 feet north of the launch pit in Sodo since July 30.
This stop was anticipated in the schedule filed with the state by Seattle Tunnel Partners, under a $1.4 billion contract to build a four-lane tube to South Lake Union by December 2015. The machine will likely restart the week of Nov. 11, said Matt Preedy, deputy Highway 99 administrator for the state Department of Transportation.
About 40 of the 250-plus cutting tools will be replaced at the front of the machine. Though it’s early in the 1.7-mile project, the machine known as Bertha has already churned through two concrete stability walls, fiberglass and grout-infused soil, so some tool erosion is normal, Preedy said. Adjustments are being made to high-pressure water systems and to the conveyor machines that remove soil, says an official update. Wheels are being replaced toward the rear of the drill, after bearing the weight of more than 5,000 arc-shaped concrete segments that form the tunnel tube.
So far, excavated muck is being trucked to disposal sites, because it is tainted by concrete grout. A barge is supposed to arrive next month at Terminal 46 to carry clean soils to the Mats Mats quarry near Port Ludlow, once Bertha moves beyond the grouted area.
Drilling is a few weeks behind the original schedule, but project director Chris Dixon said in a statement: “Bertha is functioning really well…Our crews are becoming more and more efficient as the tunnel drive progresses.” Preedy said he doesn’t expect the drill’s slow start to delay the overall tunnel completion – because Bertha will almost certainly move faster than the crews that will follow it, to build road decks.
Still unresolved is the labor dispute in which the longshore workers’ union lays claim to four waterfront muck-loading jobs per shift. A limited amount of soil handling has been done to date, by building-trades workers. “Talks are ongoing,” said Cam Williams, president of International Longshore and Warehouse Workers’ Local 19, which picketed at T-46 in August. Preedy said he hopes to resolve the issue by mid-November, when the barging begins.