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] Mine Master drill rigs (also known as underground drill rigs, master rigs or face drilling rigs) are primarily utilized in underground mines (hard rock & soft materials) and tunnel construction.
[pdf] The Kola Superdeep Borehole SG-3 (: Кольская сверхглубокая скважина СГ-3, : Kol'skaya sverkhglubokaya skvazhina SG-3) is the on Earth (since 1979), whic. .
Drilling at Kola SG-3 began on 24 May 1970 using the -4E, a serial drilling rig used for drilling . The rig was slightly modified to be able to reach a 7,000-metre (23,000 ft) depth. In 1974, the new purpos. .
The stated areas of study of the Kola Superdeep Borehole were the deep structure of the , discontinuities and the thermal regime in the Earth's crust, the physical and chemical compositio. .
The drilling ended in 1995 due to a lack of funding. The scientific team was transferred to the federal state unitary subsidiary enterprise "Kola Superdeep," downsized, and given the new task of thoroughly studying th.
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