The world’s largest tunnel boring machine bumped into a mystery object under downtown seattle last Friday bringing construction of the highway 99 tunnel to a standstill.
Nicknamed Bertha the machine was drought in from Japan to dig a two mile tunnel to replace the Alaskan Way Viaduct the five story high machine was placed about 60 feet below ground.
Bertha was stopped last Friday however when it ran into an unknown object. The stop it has given rise to all sorts of speculation but one leading theory is that the machine had hit a boulder and the soil around it is too soft to hold it firmly to drilling cranes have been set up at the site but it will take about two weeks identify the obstruction and formulate a strategy to remove it