To provide ultimate control, a sensor is installed at the discharge boom to measure the discharge height. When the desired height is achieved, the crawler track of the spreader moves in a previously designed path to start a new dump site. The slewing gear of the spreader is confined by two reversal points on the left and right side, and once the operator specifies these points, all other changes of direction are carried out automatically. When the spreader moves, the tripper car automatically follows. An absolute value transmitter, installed on the tripper car, continuously displays the position of the shifting path. The control of the travel gear is used to always position the tripper car in the middle, taking into account the travelling speed of the two travel gears, the angle position between the receiving belt of the spreader and the tripper car, as well as the left or right hand side of the belt conveyor.