Patent ID: 7963725

Claim:
A rock bolt which in use is inserted in a drill hole extending from a rock face into a rock body and which includes: a radially expandable elongate tubular member with a closed end and an opposed end in which is formed an inlet through which a pressurized fluid can pass into an interior of the tubular member, thereby to expand the tubular member in a radial direction and so effect a first frictional anchoring action of the tubular member with a wall of the drill hole at a first location near a mouth of the drill hole; a mechanical expansion anchor unit that is operable to effect a second anchoring action with the wall of the drill hole at a second location that is displaced from the first location; a bearing plate mounted on said opposed end of said tubular member for engaging the rock face when the rock bolt is inserted in a drill hole; and a further elongate member having a first end secured to the closed end of the tubular member and a second end that is threadedly connected to the mechanical expansion anchor unit, and which is rotatable relative to the mechanical expansion unit for operating the mechanical expansion unit to effect the second anchoring action independently of the operation of the first anchoring action.