Plow Unit, Coal

a set of equipment used for narrow-web coal mining consisting of a coal plow, upper and lower drive gears with electric motors, a mobile scraper face conveyor, and a system of hydraulic or pneumatic jacks. The plow is forced along the longwall between the face and the conveyor, breaking up the seam to a depth of 70–100 mm. It may cut through the entire thickness of the seam, or it may leave the top part of the seam, which will cave in later under the force of gravity and rock pressure. The plows that cut and load the coal onto the conveyor may be stationary, in which case the cutters are rigidly fixed to the body, or moving, that is, the cutters make striking or vibratory movements. Stationary plows have become common.

Plow complexes provide for the integrated mechanization of stoping operations when the plowing method is used. In addition to the plow equipment, they include mechanized roof supports whose hydraulic jacks move the entire complex. The plowing complex is the principal type of equipment used for plowing coal seams. It cuts, loads, and delivers the coal, supports the roof in the working area, and moves all the equipment behind the advance of the face of the longwall. Complexes are rated at 440–800 kilowatts per worker. The plow moves at speeds of 0.6–1.8 m/sec, and the scraper chain of the conveyor at speeds of 0.6–1.2 m/sec.

The most efficient and promising device for plowing is the plow aggregate, which combines in one unit one or several plows, a drive system, means for delivering the coal along the face, and mechanized roof support. The aggregate makes it possible to mine coal without the constant presence of workers at the working face by using systems for automatic and remote control of the equipment.