noun
(mining) The surface of coal exposed by mining, or a part of a coal seam that is currently being mined.
(mining) The end of a drift, entry, or room in a coal mine.
(figurative, UK) A place where difficult or strenuous work is done.
(figurative, UK) A place where more tangible, practical, or direct work of an activity is done, as opposed to theoretical or managerial work.