Rock bolt

A rock bolt comprising:

• an elongate, generally circular tube, the tube having a leading end and a trailing end;
• an expander mechanism disposed within the tube in a region of the leading end;
• and
• an elongated tendon disposed longitudinally within the tube and in connection at or towards a first end of the tendon with the expander mechanism and in connection at or towards a second and opposite end of the tendon with an anchor arrangement positioned at the trailing end of the tube,
• the tendon being actuatable to actuate the expander mechanism and to remain connected between the expander mechanism and the anchor arrangement while the expander mechanism is actuated,
• wherein the tube has an opening in the region of the leading end and the expander mechanism includes first and second cooperating expander elements, in which the first expander element is attached to an end of the tendon for movement axially within the tube towards the anchor arrangement upon actuation of the expander mechanism and the second expander element is restrained relative to the tube opening, the second expander element being shifted radially through the tube opening as the first expander element is shifted axially within the tube towards the anchor arrangement.