adit |
| noun
- A horizontal or nearly horizontal passage from the surface into a mine as contrasted to a shaft which is a vertical entry passage. An adit may be used for ventilation, haulage, drainage, or other purposes.
| | air shaft |
| noun
- a vertical (or near vertical) shaft that supplies ventilation to a tunnel or other underground facility
| airway |
| noun (plural airways)
- (anatomy) The trachea.
| anthracite |
| noun
- A form of carbon; the hardest and cleanest-burning of all the coals.
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