It’s finally happening. Soon we will all feel the earth move – and big Bertha, the world’s largest tunneling machine, couldn’t be happier. The old girl’s been champing at the bit for months to sink her teeth into Seattle dirt, and before she’s done, Bertha’s red and yellow grinders and steel cutters will have eaten her way through 850,000 cubic yards of soil, crunching away at 35 feet a day. The goal is have the 1.7 mile tunnel and roadway complete by late 2015.

Since arriving by ship from Japan in 41 separate parts on a cloudy early April afternoon, crews have been reassembling the 7,000 ton beast of burden. On the final day of May, Bertha was lowered into an 80-foot deep by 80-foot wide pit. Since then, the behemoth dirt digger has gone through “hundreds of tests” to make sure she’s ready to pound sand, says Washington Department of Transportation spokeswoman KaDeena Yerkan.

A definitive date as to when the drilling will begin has not yet been set, but WSDOT is fairly certain it will take place sometime in the last ten days of July.

When Bertha does roar into action, a crew of more than 30 engineers and mechanics who will be aboard the 326-foot long machine – about as many workers as it takes to operate a nuclear-powered submarine – will work her 20 hours a day Monday through Friday, in two-ten-hour shifts. Weekends will be devoted to maintenance.

On Saturday, July 20, a public dedication ceremony is planned near Bertha’s pit, just west of CenturyLink Field. Yerkan expects Gov. Jay Inslee to be at the public event.

“We’re still planning it, but I’m sure we’ll be smashing some bottles of champagne over Bertha,” says Yerkan.