E21C27/00—Machines which completely free the mineral from the seam
E21C27/10—Machines which completely free the mineral from the seam by both slitting and breaking-down
E21C27/14—Machines which completely free the mineral from the seam by both slitting and breaking-down breaking-down effected by force or pressure applied to side of slit, e.g. by wedges
E21C27/16—Machines which completely free the mineral from the seam by both slitting and breaking-down breaking-down effected by force or pressure applied to side of slit, e.g. by wedges with means for both slitting and breaking-down