Definitions for "Drift mine"
Keywords:  outcrop, seam, coal, mine, mountainside
type of mine created to access coal seam exposed by the slope of a mountain, characterized by an entrance that is a horizontal tunnel into the seam of coal
A coal mine that enters a flat lying coal seam in a mountain, usually at the “outcrop” or location where the seam of coal exits the mountainside.
Mine that opens into a level or nearly level seam of coal