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- The mixture of gases that surrounds the Earth and forms its atmosphere; composed by volume of 21% oxygen and 78% nitrogen; by weight about 23% oxygen and 77% nitrogen. It also contains about 0.03% carbon dioxide, some aqueous vapor, argon, and other gases. Hartman, 1
- The current of atmospheric air circulating through and ventilating the workings of a mine.
- Atmospheric air delivered under compression to bottom of drill hole through the drill stem and used in place of water to clear the drill bit of cuttings and to blow them out of the borehole. Long
- Air piped under compression to work areas and used to operate drilling or mining machinery. See also: air circulation
Source: Dictionary of Mining, Mineral, and Related Terms