Abstract: Disclosed is a method of adapting a metal bar, for use as a rock bolt, to ensure that the bar will break in a predictable manner, the method including the step of removing material from the bar in a circumferential band to reduce a diameter of the bar within the band to a minor diameter thereby to provide a failure zone within which the bar will break if subjected to enough tensile load.

Abstract: A self-drilling rock anchor assembly includes: a friction fit tubular sleeve extending longitudinally between leading and trailing ends; a rod extending through the sleeve between first and second ends, and projecting from each sleeve end; a drill bit member engaged with the rod's first end having an exterior surface part of which tapers towards a back end of the member; a backstop element engaged with the rod's second end having a first drive surface; a load bearing element on the rod between the sleeve's trailing end and the backstop that has a second drive surface. The rod moves relative to the sleeve between a drill position, wherein the drill bit is spaced from the sleeve's leading end, and an insertion position, wherein the sleeve's leading end abuts the bit. The drill and insertion positions are achieved by applying a force to the first and second drive surfaces, respectively.

Abstract: A tool to aid in the installation of a rock bolt assembly in a rock hole which includes a drive shaft having a proximal end, which is adapted to engage with a drilling rig, and a distal end which includes a recess which is adapted to receive a trailing end portion of the rock bolt and which has a first seat against which an axially pre-set component of the rock bolt assembly abuts, a tubular sleeve telescopically engaged with the shaft which has a first end, which is adapted to receive an axially moveable component of the rock bolt assembly and which has a second seat against which the axially moveable component abuts, and a second end, wherein the sleeve is reciprocally moveable relatively to the shaft between a biased forward position in which the axially pre-set component and the axially moveable component are spaced, and a retracted second position in which the axially pre-set component engages or connects to the axially moveable component.

Abstract: A rock anchor assembly includes: a resiliently radially deformable tubular member longitudinally extending between leading and trailing ends and which has an arrestor formation integral with, or engaged to, a trailing end part of the member; an elongate element longitudinally extending through the member between first and second ends and which attaches to the tubular member at spaced distal and proximal load points and which has a failure arrestor fixed at a point within the member; and a faceplate on the tubular member or the elongate member. When the assembly is inserted in a rock hole, with the faceplate bearing against the rock face, and load is applied along the elongate element that will cause the element to sever above the point at which the arrestor is fixed, the failure arrestor engages the arrestor formation, arresting the ejectment of a proximal portion of the elongate element from the hole.

Abstract: Disclosed is a grout anchored rock bolt which includes an elongate cylindrical body of a suitable material which has at least one integral anchor portion which includes of a plurality projection, each of which extends laterally from the body in at least one radial direction, wherein the projections are consecutively serially arranged along the length of the anchor portion and wherein each projection is radially offset relatively to the preceding formation at an angle that is not orthogonal.

Abstract: Disclosed is a resin bolt which includes an elongate shaft which extends between a leading end and a trailing end and a positioning head which is integral to the shaft at the leading end and which extends in the elongate axis of the shaft from a perimeter rim to a crown, with the head formed with a plurality of projections, with each projection extending laterally, beyond the radial dimension of the shaft and each projection having a leading surface which slopes, at least partially, from the crown to the perimeter rim, and a trailing surface from the perimeter rim to the shaft.

Abstract: A method for putting together a down-the-hole drilling apparatus for plastic pipe drilling. The down-the-hole drilling apparatus has a drilling device for carrying out drilling by using a drilling unit with a plastic pipe, which drilling unit includes in its drilling head a drilling arrangement. The plastic pipe is arranged to be pulled into the hole to be drilled by a power influence directed thereto from the drilling unit, being coupled with the second drilling means in a manner transmitting power at least in the longitudinal direction of the drilling device. The drilling unit and the plastic pipe are coupled by a skirt part that exists at an opposite end of the drilling arrangement, with respect to the drilling surface of the drilling unit, which skirt part has an internal protrusion assembly in radial direction.

Abstract: A drilling device for a down-the-hole drilling apparatus. The drilling device includes in a guide, a drilling member and a flushing mechanism configured to flush drilling waste. The drilling mechanism includes first and second drilling bit arrangements that are movable with respect to the drilling device and that are arranged to be expanded to drill a hole having a greater cross-sectional surface area than an end of the casing and arranged to be reduced to a size smaller than the end of the casing. Bit pieces of the second drill bit arrangement expand and reduce the second drill bit arrangement. The bit pieces expand the second drill bit arrangement by moving in a radial direction outwards in slide grooves, by rotating the guide in a drilling direction, and move in the radial direction inwards in the slide grooves, by rotating the guide in an opposite direction.