the inclined guide plate 17 as is usual the guide 15 is formed in sections which correspond to the sections of the conveyor 16 each cutter body 10a and 10b is provided with a respective carrier 22 each of which is equipped with two floor cutters 23 one floor cutter of each carrier being operative in a particular direction of travel of the plough further cutters may be provided on the carriers 22 the carriers 22 are mounted on respective pivot pins 24 to pivot freely on the corresponding plough bodies 10a and 10b the pivot pins 24 extend parallel to the coal face and in the direction of movement of the plough that is to say the longitudinal direction of the face thus the carriers 22 are mounted on their plough bodies 10a and 10b so as to pivot towards and away from the coal face the floor cutters 23 which are removably mounted at the ends of their carriers 22 carry out a control or stress relieving cut to a depth s at the floor level 25 and immediately in front of the front coal face side edge 26 of the floor plate 21 this edge 26 has a guide and abutment surface 27 which is inclined in relation to the floor 25 and against which each of the carriers.