The name Bertha, after Seattle's first female mayor, , was chosen by a panel (that included the Governor and Transportation Secretary) from 150 submissions from kindergarten through 12th graders, who were asked to submit female names with Washington state heritage. The winning entry, which was submitted by two elementary schools in and , was selected in December 2012.
[pdf] Incorporated in Australia in 1990, Terratec is the world’s leading designer and manufacturer of Tunnel Boring Machines, Raise Boring Machines and other custom-engineered products for the tunnelling and mining industries, encompassing all ground conditions and boring diameters from 0.6m to 15m.
[pdf] The was developed by Sir to excavate the in 1825. However, this was only the invention of the shield concept and did not involve the construction of a complete tunnel boring machine, the digging still having to be accomplished by the then standard excavation methods.
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