WSDOT reported that Bertha has slowly began moving again. It must tunnel through 20 feet of unreinforced concrete with its broken seal to break through into the rescue shaft. Once that happens, the repairs to her cutterhead can commence. The Seattle Tunnel Partners predict Bertha will overheat, as she did before stopping for repairs. If that occurs, they will stop tunneling to wait for the machine to cool before continuing. STP crews also chipped away at a Bertha-sized cut-out in the access shaft to make for a cleaner breakthrough. See video below. [Source: WSDOT and WSDOT YouTube Channel. Image: YouTube]
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Urban miners have been busy constructing a new water supply tunnel underneath New York City to supply the megalopolis with the water it needs. The miners, or sandhogs as they are known, are about halfway complete with the new tunnel which is expected to be in service by the year 2020. Work on the 60-mile tunnel began in 1970 and the total projected cost is $6 billion and is widely regarded as one of the most complex public works projects in the western hemisphere. When complete, it will help deliver 1.2 billion gallons DAILY to 8 million New Yorkers. The city currently gets its drinking water from two water supply tunnels that were constructed in the early 20th century and have not been inspected or repaired since then. More after the break. (Image credit History.com)