What's blocking 'Bertha' still a mystery

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by KING 5 News

KING5.com

Posted on December 11, 2013 at 5:06 PM

Updated Wednesday, Dec 11 at 8:50 PM

Transportation crews still don't know what exactly is blocking the path of "Bertha," the giant boring machine that's drilling the new Highway 999 tunnel under Seattle.

The machine was stopped on Friday after encountering an object 60 feet under South Main Street. On Tuesday, the Washington Department of Transportation and Seattle Tunnel Partners brought in cranes with drills and crews were preparing to drill down to get a closer look at the mysterious object.

"We don't know what it is," Chris Dixon with Seattle Tunnel Partners said during a news conference Wednesday. "Right now, we're developing plans to access that area underground to see exactly what it is that's limiting the progress of the (tunnel boring machine). And it's going to a while to implement these plans and see what exactly the situation is."

WSDOT officials said it could be something stuck in the tunnel boring machine behind the cutting head or something in front of it. WSDOT wants to send men into the tunnel to see Bertha and get eyes on the object.

The area is not pressurized, so they have to set up hyperbaric chambers using special divers. Crews might drill down to the tunnel from above to help stabilize the soil so workers can get down there.

The waterfront is filled with sandy silt, parts of Seattle that were scraped away a century ago and dumped there.

And it's anybody's guess what the mysterious object is.

"There's thousands of guesses what's going on, but until we get down there and see what the actual situation is, it's just speculation and guesses," said Dixon.

WSDOT said it could take a week to get set up and get workers in front of Bertha's blades. They also don't know how much the delay will cost.
 

(Photos in video courtesy MOHAI)

KING 5's Liza Javier and Linda Brill contributed to this report.

 

 

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