pioneer tunnel

noun

variants or pioneer bore
: a small tunnel parallel to a main tunnel and well in advance of the completed main tunnel so that by crosscuts to the line of the main tunnel several headings can be exposed and work expedited

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Cite this Entry

“Pioneer tunnel.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pioneer%20tunnel. Accessed 22 Feb. 2024.

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