We won’t know more about Bertha’s blockage until 2014

Posted on Dec 20 2013 3:11 PM

People love a good mystery. That would explain why we’ve been all over the national news this week, and why we’re continuing to be flooded by questions (and suggestions) about what’s blocking Bertha, the SR 99 tunneling machine.

Unfortunately, the only answer we have to offer isn’t very satisfying: we simply don’t know yet.

But we have a plan and we’re working hard to get Bertha moving again. Last week, our contractor, Seattle Tunnel Partners, started drilling wells to pump water out of the ground near Bertha. So far, they’ve removed more than 300,000 gallons. If that sounds like a lot of water, you’re right. It is. And there’s a lot more where that came from.

On Wednesday, crews were able to turn the machine’s screw conveyor and remove some muck from the excavation chamber. As the muck lowered, a crew member was able to take a quick peek through a hatch near the top of the machine. What they saw inside was dirt, sand and cobbles – nothing extraordinary. Because water quickly filled the part of the chamber that was previously occupied by muck, they were only able to look around for a few minutes before they had to close the hatch.

Since our visual inspection yielded no obvious clues about what is going on in front of or inside the machine, our next step is to continue doing what we’ve been doing: lowering the water pressure around Bertha so crews can get a closer look.

Over the holidays, we’ll be drilling more wells, maintaining Bertha and preparing to reconfigure the launch pit so construction of the highway within the tunnel can begin. We’ll continue to update you on our progress, but we don’t expect to know more about what’s blocking Bertha until after the first of the year.

We’ve received a lot of questions about how the stoppage in tunneling might affect the project’s cost and schedule. It’s too early to tell. Our focus is now on addressing this issue safely and in a timely manner so we can resume tunneling as soon as possible.

We hope you have a fantastic holiday season. It’s been a productive year for Bertha and the tunnel team, and we can’t wait to dig into 2014.

Previous updates

Dec. 13, 2013 update -- Tunnel crews lowering groundwater to get a closer look at what's blocking Bertha

Dec. 5, 2013 update -- Seattle Tunnel Partners: Almost the proud owners of the world's largest tunneling machine

Nov. 25, 2013 update -- Bertha has much to be thankful for as she nears South Jackson Street

Nov. 14, 2013 -- Bertha takes on the complexities of King Street

Nov. 7, 2013 -- Several days at the dentist: new teeth will give Bertha more bite