Boring Bertha Back to Eating Dirt after Month Delay

Sep 23, 2013

The drill known as Bertha is back to eating dirt after a slow start, then a delay, then a delay caused by the delay.

The massive machine boring the Highway 99 tunnel beneath Seattle had been sitting still while two labor unions duked it out over a handful of jobs.

Gov. Jay Inslee announced last week he’d brokered a deal in the dispute, and said the digging would resume after a few days.

But ground-up earth and concrete had solidified inside Bertha during the downtime. Project Manager Chris Dixon said scooping it out and making some additional modifications that had been planned for later did cost them a few days, but only in the short term.

“Were very glad that we took those few extra days because it’s certainly going to pay dividends for the next few hundred feet, and it’ll continue to pay dividends for the balance of the tunnel drive,” he said.

Bertha has chewed through a thick concrete wall just west of Pioneer Square. Now it has moved into a section of earth stabilized with pillars of cement, where it’s expected to trudge forward about 6 feet a day. That rate will pick up as the machine moves into normal dirt.  

Dixon said the project is still expected to finish up in late 2014. He and a Washington Department of Transportation official said they don’t yet know how much the delay will cost, or who will have to pay.