It appears that more dump trucks have been called into service earlier this week to speed up the digging process or to catch up from three lost days last week. On Tuesday morning at about 7:30, there were 31 dump trucks queued up to haul dirt from the bus box.  I could not get the line of trucks in one photo so  here is a  28 second video from my friend Carol of the parade of trucks.

It doesn’t take long to fill those trucks and send them on their way. To do the job, Kiewit uses a John Deere 450C LC excavator (if you are into specs, check this out). Three scoops from its giant bucket and a truck is full.

The excavator gets help from a Caterpillar D8T bulldozer (50 second video here demonstrates its size). It pushes dirt from the floor of the bus box to within reach of the excavator. In the photo below, notice the slit of yellow above the blue pipes and below the excavator. That’s the roof of the dozer working in the bus box hole. I took the photo from the light rail platform while standing on bench across Wewatta Street.

By the way, on Monday the dozer got stuck in the bottom of the hole. Another excavator came to the rescue and dug it out. The wet ground from last week’s snow storm probably contributed to the problem.

Since some components of the dewatering system are still being installed, I believe (unconfirmed) that Kiewit is not yet digging the bus box hole to its eventual depth of 28 feet. I’d say they are currently digging to a depth of about 15 feet.  The top layer of dirt is contaminated (not toxic) so they are disposing of it off site. The deeper, cleaner dirt will be recycled on site and used for backfill around the completed bus box. In the meantime, the top layer of dirt is being hauled away at an incredible pace. You can see the progress in this photo.