A vertical passage which provides access or ventilation to an underground excavation or chamber. Use only if function is unknown, otherwise use specific term.
||A horizontal tunnel opening from the surface used for haulage, access to a mine, exploration or drainage.
||A vertical shaft providing access to the lower tunnels in a coal mine.
||A vertical or inclined excavation giving access to an underground mine.
||An artificial underground channel. Use specific type where known.
||A shaft sunk into the ground to provide a supply of water.