The invention relates to a device for determining the cutting horizon of a mining winning system, having a movable conveyor which is composed of individual pan elements, and having at least one optical detection sensor which has a sensor head that is received in a sensor carrier and can be pressed with at least one pressure means against a coal/basement rock boundary layer. In order to improve the sensing and working reliability, over the length of the conveyor, a plurality of pan elements are configured as sensor pans which are provided with a protected recess which is open to the basement rock and in which the sensor carrier is arranged or can be arranged such that it can be disassembled together with the sensor head.