Sandvik Ab

Eric Ivan Johnson

Steven Lee Weaver

Michael Andrew McLean

An elongate roof bolt includes a bolt body having an axially extending central bore and defining a leading end. The leading end includes a pair of axially extending abutment elements formed by machining. Each abutment element includes an abutment face for engagement with a drill tip on opposite sides thereof, to transmit rotary forces during drilling. The drill tip extends across the leading end of the bolt body and is bonded to the abutment elements by welding, soldering or brazing. The bore opens out of said bolt bonded adjacent said leading end.

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Warners Bay, Australia

Eric Ivan Johnson