Seattle's Tunnel Machine Chokes on Dirt

State officials said Friday afternoon that the tunneling machine known as Bertha had to stop, not because it hit foreign objects, but because it clogged with dirt.

Bertha is digging an underground highway to replace Seattle's Alaskan Way Viaduct.  Officials could not say why the $80 million tunnel boring machine would choke on dirt.

Bertha has been largely stuck since early December, when it was stopped after running into a steel pipe.