Abstract: A disc-shaped rotary cutter for continuous excavation of hard mineral rock layers according to the invention includes a supporting element having a plurality of end faces and a plurality of cutting elements formed on a circumference of the supporting element and the plurality of end faces. According to the invention, the rotary cutter provides a cylindrical compressive strength of equal to or greater than 20 MPa.

Abstract: A bucket wheel has a conical supporting body constructed as an inner shell rotatably mounted on the bucket wheel axis and a device which co-operates with the supporting body to accommodate the buckets on the outer rim of the bucket wheel. The supporting body is prolonged radially by a prismatic-type outer shell arranged on the supporting body parallel to the device, which has cell-forming dividing walls on its radially outward peripheral region. The prismatic shell, viewed in the radial direction, is shaped from a plurality of approximately trapezoidal steel plates which are welded to one another, making a plurality of bends, to form a polygonal conical envelope.