Tuesday, April 04, 2017

Seattle's massive tunneling machine, Bertha, breaks through the wall


The (formerly) world's largest tunnel-drill machine Bertha broke through its final rock just before 11:30 a.m. today (after years of delays).


Bertha began tunneling on July 30, 2013. It’s expected to finish on April 4. That’s about 1,345 days, or about 32,280 hours. The machine traveled about 9,270 feet (1.755682 miles) over that period, which puts its speed at about 0.00005438915 mph. 
For comparison, garden snails travel at a rate of speed more than 10 times faster (0.000621371 mph or 1 meter/hour), according to a British researcher.
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