A method for controlling a longwall mining operation, including a face conveyor, at least one extraction machine, and a hydraulic shield support, in underground coal mining. Using inclination sensors disposed on at least three of the four main components of each shield support frame, such as floor skid, gob shield, support connection rods, and gob-side region of the top canopy, the inclination of the shield components relative to horizontal is ascertained in the direction of step. In a computer, the ascertained inclination data is compared with base data stored in the computer that defines the geometrical orientation of the components and their movement during stepping. From the comparison, a respective height of the shield support frame, at the forward end of the top canopy, is calculated as a measure for the face opening.