Method of automatically producing a defined face opening, in underground coal mining, during longwall mining operations having a face conveyor, a disk shearer loader and a hydraulic shield support. Via at least one inclination sensor on the top canopy of the shield support frame, the inclination of the top canopy relative to the horizontal, in the direction of mining or extraction of the disk shearer loader, is determined to provide angles of the course of an overlying stratum at the shield support frame. A stepping path length of each shield support frame is detected, and therefrom a cutting depth of the disk shearer loader during an extraction run is determined. A cutting height of the disk shearer loader is detected by means of sensors disposed thereon, and a cutting height of the disk shearer loader is adjusted in alignment with the angle of the course of the overlying stratum to produce the defined face opening.