Résumé
Drift mining is either the mining of an ore deposit by underground methods, or the working of coal seams accessed by adits driven into the surface outcrop of the coal bed. A drift mine is an underground mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into the ore seam. Random House dictionary says the origin of the term "drift mine" is an Americanism, circa 1885–1890. Drift is a more general mining term, meaning a near-horizontal passageway in a mine, following the bed (of coal, for instance) or vein of ore. A drift may or may not intersect the ground surface. A drift follows the vein, as distinguished from a crosscut that intersects it, or a level or gallery, which may do either. All horizontal or subhorizontal development openings made in a mine have the generic name of drift. These are simply tunnels made in the rock, with a size and shape depending on their use—for example, haulage, ventilation, or exploration. The Boulder-Weld Coal Field beneath Marshall Mesa in Boulder, Colorado was drift mined from 1863 to 1939. Measurements in 2003, 2005, and 2022 showed that the mine has an active coal-seam fire. It was investigated as a possible cause of the 2021 Marshall Fire. Argyle Lake State Park's website says the Argyle Hollow (occupied by a lake since 1948) has been rich in coal, clay and limestone resources. Historically, individuals commonly opened and dug their own "drift mines" to supplement their income. In Appalachia, small coal mining operations such as these were known as "country bank" or "farmer" coal mines, and usually produced only small quantities for local use. The Lusk Mine, now in Turkey Run State Park, was in operation from the late 1800s through the late 1920s. Too small for commercial operation, the mine probably provided coal for the Lusk family and later for the park. In 1820 the first commercial mine in Kentucky, known as the "McLean drift bank" opened near the Green River and Paradise in Muhlenberg County.
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