In hard rock mining and quarrying, this is achieved through a controlled process of drilling and blasting. A blast hole drill rig is a specialised piece of equipment that creates a series of holes in a specific pattern, depth, and diameter across a section of rock known as a “bench.”
[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 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.
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