The initial digging of Duluth’s ship canal was fairly simple. The steam-powered dredging tug Ishpeming began chewing through Minnesota Point in September 1870, stopped when the ground froze in ...
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A 21-ft, 8-in dia earth pressure balance tunnel boring machine has launched in Seattle to begin creation of a 2.7-mile-long tunnel that will store combined sewer overflow as part of the city's consent ...
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