CPC E21D 21/004 (2013.01) [E21B 10/42 (2013.01); E21B 17/042 (2013.01); E21B 17/046 (2013.01); E21D 21/0033 (2013.01)] | 22 Claims |
21. A drill bit for use in a drilling assembly for drilling a borehole in a rock body and inserting a rock bolt within the borehole in a single pass, the drill bit comprising:
a drill bit body arranged to be detachably joined to the downhole end of a drill string, the drill bit having an external screw thread extending in an axial direction of the drill string, wherein the external screw thread is configured to cooperate with a thread engaging formation provided at or near a downhole end of a friction bolt sleeve so that the drill bit is able to be screwed into the friction bolt sleeve;
wherein the drill bit body is substantially frustoconical having a conically tapered side wall, and wherein the external screw thread extends along the length of the tapered side wall.
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