The cut is typically a rectangular, horizontal cut from a highwall bench, reaching depths of several hundred feet or deeper. Hogsback - A sharp rise in the floor of a seam. Hoist - A drum on which hoisting rope is wound in the engine house, as the cage or skip is raised in the hoisting shaft. Hoisting - The vertical transport coal or material. Hydraulic - Of or pertaining to fluids in motion.
Hydraulic cement has a composition which permits it to set quickly under water.
Hydraulic jacks lift through the force transmitted to the movable part of the jack by a liquid. Hydraulic control refers to the mechanical control of various parts of machines, such as coal cutters, loaders, etc., through the operation or action of hydraulic cylinders. A belt conveyor incline is termed a slope. Incompetent - Applied to strata, a formation, a rock, or a rock structure not combining sufficient firmness and flexibility to transmit a thrust and to lift a load by bending. The points of observation are to 1 miles apart.