Terminology (how we refer to things) is important. THEN uses the following terms.

Term What it means
adit horizontal, or mostly horizontal, passage in a mine that opens to the outside
drift horizontal, or mostly horizontal, passage in mine; may open into a shaft
drifting creating a drift
main main line of a railway
portal the mouth of an adit, i.e., that area surrounding the location where an adit opens to the outside
shaft vertical, or mostly vertical, passage in a mine
sinking excavating a shaft
spur section of railway track connected to the main at one end; unlike a siding, which is connected to the main at both ends
tailings material left over after mined material has passed through a mill; usually stored in tailing piles or ponds
waste rock rock from a mine that is cast aside before milling because it contains little or no useful ore. In many early Yukon copper mines that were dug by hand, bits of rock were sorted manually. Waste rock was piled adjacent to the mine entrance. In later mines, which were excavated by machinery, much larger quantities of waste rock were trucked some distance from the mine and spread around in big flat piles by bulldozers.
wye fixed Y-shaped configuration of tracks that allows a locomotive or railway cars to be turned around or to permit access to a spur by a train travelling in either direction on the main

TimmiT History Exploration Notebook