Abstract: A cable bolt is provided that is suited to stabilize rock surfaces, particularly to withstand loads placed on the cable bolt when tensioned to stabilize rock surfaces of coal mines. The cable bolt comprises a tendon composed of a plurality of strands, the tendon having a plurality of pre-formed bulbous portions. The bulbous portions house rigid elements, such as a ball bearing, which are inserted after the bulbous portions are formed. When the cable bolt is tensioned or stressed, the load placed on the bulbous portion will be resisted by the rigid element housed within the bulbous portion, thereby preventing the bulbous portion from collapsing.

Abstract: A yielding rock bolt having a solid metal shaft with a relatively wide portion and a relatively narrow portion and an anchor member mounted about the shaft. The anchor member has longitudinal bore which is of lesser dimension than the relatively wide portion. The anchor member is mounted about the relatively narrow portion adjacent the wide portion. In use the shaft is extruded through the anchor member to cause the rock to yield as a rock face moves.

Abstract: A cable bolt is provided that is suited to stabilize rock surfaces, particularly to withstand loads placed on the cable bolt when tensioned to stabilize rock surfaces of coal mines. The cable bolt comprises a tendon composed of a plurality of strands, the tendon having a plurality of pre-formed bulbous portions. The bulbous portions house rigid elements, such as a ball bearing, which are inserted after the bulbous portions are formed. When the cable bolt is tensioned or stressed, the load placed on the bulbous portion will be resisted by the rigid element housed within the bulbous portion, thereby preventing the bulbous portion from collapsing.

Abstract: A yielding rock bolt arranged to be inserted into a hole in a rock surface. The rock bolt comprises a shaft having a widened portion adjacent a first end thereof, arranged, in use, adjacent an inner end of the hole. The rock bolt also includes an anchor member arranged to be secured within the hole in the rock surface. A longitudinal bore is provided in the anchor member to receive a second end of the shaft, the longitudinal bore being of a diameter slightly less than that of the widened portion of the shaft. A rock face engaging means is provided adjacent a second end of the shaft to secure the second end of the shaft adjacent the rock face. Movement of the rock face causes the widened portion of the shaft to be pulled through the longitudinal bore in the anchor member.

Abstract: Apparatus and method for manufacturing multi strand rock bolts having spaced apart bulbs (12), wherein there is a feed means (14, 16, 18 and 19) for supplying a multi strand cable (11) from a rotatable supply wheel (13). Means (30, 32, 35 and 38) is provided for forming the cable (11) with bulbs (12) at spaced intervals and the position of the cable (11) is determined by a sensor means (40).

Abstract: A rock anchor is formed from a tendon composed of a plurality of strands. The tendon has at least one bulbous portion wherein all the strands in the bulbous portion are spaced apart from one another substantially around the periphery of each bulbous portion. An apparatus for manufacturing the rock anchor includes a series of opposed plates disposed on opposite sides of the tendon and controlled by respective hydraulic rams to clamp the tendon between the opposing plates. The clamps are sequentially displaced longitudinally by a dedicated hydraulic ram to form the bulbous portion between adjacent clamps.