tunnel blasting

tunnel blasting

[′tən·əl ‚blast·iŋ]
(engineering)
A method of heavy blasting in which a heading is driven into the rock and afterward filled with explosives in large quantities, similar to a borehole, on a large scale, except that the heading is usually divided in two parts on the same level at right angles to the first heading, forming in plan a T, the ends of which are filled with explosives and the intermediate parts filled with inert material like an ordinary borehole.
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References in periodicals archive ?
Once the portal on both sides is cut back and secured the main tunnel blasting begins.
Having witnessed the wind tunnel blasting of both the Johnny Patrick and Fat Chops Big Bands in the last few months the BBC Big Band sounded much more sedate from the vantage point of Symphony Hall's Level 5.