Abstract: A hardmetal drill bit button is restored by forming its head to a chisel shape. Various chisel shapes and a machine for the purpose are disclosed. Also disclosed are various kinds of grinding wheels for the purpose, and a method and means for simultaneously dressing the steel of the bit body.

Abstract: A wire line core barrel inner tube assembly has a latch body with a miximum diameter portion providing a shoulder seatable on a drill string landing ring and a fluid bypass channel extending through the maximum diameter portion and a valving assembly. The valving assembly includes a resilient valve seat in the bypass channel and a ball seatable on the valve seat to block fluid flow in a downward direction through the channel, movable upwardly off the valve seat from the seated position to permit fluid flow through the seat in the opposite direction and movable through the seat to a channel open condition after a preselected fluid pressure has been exerted on the ball in a direction to move the ball from the ball seated position and through the valve seat.

Abstract: In a high temperature seal between a closure member and a rim with interengaging hard metal rings, the ring on the rim rests on a conical shoulder and the underside of the ring is complimentary shaped, so that as the shoulder expands circumferentially the ring slides down the conical surface and remains bedded on the shoulder.

Abstract: A hardmetal ring is a size for size or low interference fit on the body of a disc cutter of a rock working machine, such as a boxhole borer. In one embodiment the ring is gable shaped and clamped between a fixed annular shoulder and a detachable annular shoulder. In another embodiment the ring is triangular in section and two annular shoulders resting on it and inclined surfaces on the body clamp the ring to the body.

Abstract: A chuck for a drilling machine is fitted to a retractable spindle 21. Plungers 25 carried by a yoke 26 move when the yoke 26 abuts the front end 20 of the machine. This charges an accumulator carried inside the chuck body. Opening a valve 39 causes the chuck jaws to clamp while closing the valve 39 and opening a valve 55 causes the chuck jaws to relax.

Abstract: The invention provides a method of joining two rigid tubes such as are used in drill stems wherein a nipple internal to the tubes is threaded and screws into at least one of the tubes, the nipple provided with a zone of reduced internal diameter which registers with a cavity in the internal bore of the tube and the zone of reduced internal diameter expanded outwards into contact with the tube to occupy the registering cavity in the tube and form a positive lock against tensile forces.

Abstract: In a diamond impregnated bit scourer particles in the form of silicon carbide are added to the matrix. The mesh size of the silicon carbide is less than that of diamond and the concentration preferably about 40, if the diamond concentration is 40.

Abstract: A deep level mining method wherein conventional mining takes place to recover ore and pillars are left for support purposes. The ore in the pillars is recovered before or after their formation by drilling overlapping holes into the reef in the pillars.The holes are plugged thereafter to restore the supporting function of the pillars.

Abstract: A borehole guide for drilling interpenetrating boreholes which may be parallel to one another or inclined to one another. The borehole guide is clamped in position in an already drilled borehole by inflating an inflatable member. Thereafter a drill which is directed by the guide is used to drill a second borehole which overlaps the first hole. A number of the borehole guides may be used end to end, and their relative orientation may be varied to direct the second borehole, within limits, along a desired path.

Abstract: Deflection wedges are positioned in a generally horizontal drill hole in a predetermined orientation by means of a device which fits on the end of a drill string and is positioned in the hole. The deflection wedges positioned at the end of the device, and the device includes a unit which triggers at the predetermined angular orientation, to indicate that the wedge is correctly oriented. The orientation unit has a through passage for pressure fluid and a transverse passage intersecting the through passage. A blocking member is movable in the transverse passage and at a particular orientation moves along the transverse passage across the through passage. When crossing the through passage, the blocking member is entrained by the pressure fluid flow and moves to a position where it blocks the through passage, thus providing a signal to an operator that the unit is correctly positioned. The wedge is then secured in that position and the device withdrawn from the hole.

Abstract: A deflection wedge is positioned in a long horizontal drill hole by securing it with a shear pin to an extension on a drill string. The extension is turned independently of the drill string to enable a droparm mechanism to actuate a trigger which stops rotation at a predetermined orientation. Rotation is effected by means of a rifle bar mechanism. The rifle bar presses against the bottom of the hole to cause rotation and the trigger declutches the rifle nut when the droparm drops.

Abstract: The invention concerns down-the-hole drilling, where there is a persistent problem in providing an adequately controlled flow of flushing fluid to the face of the drill bit. In known down-the-hole drills turbulence and closed circuits of the flushing fluid tend to erode the bit and reduce its lifespan. The invention seeks to lessen these drawbacks by providing for the flow of flushing fluid to be divided into a component directed along a first cavity which terminates at the face of the bit and another component directed along a second cavity which terminates above the face and is deflected up the drill hole. Weakening of the bit is avoided if there is at most one bore through the bit for flushing fluid.

Abstract: A coupling thread structure for percussion drill elements including a rod (10) having an external thread (14), and a sleeve (24) having an internal thread (26) with the threads, when the sleeve and rod are coupled, having abutting (16) and non-abutting (18) flanks and with the flanks being joined by bottom (22) and crest (20) portions, wherein the threads have at least two starts; the abutting flanks (16) are substantially straight along their whole abutting contact portions (CL) and form an angle of between 10.degree. and 25.degree., preferably 15.degree. to 20.degree., with the drill axis; the pitch angle of the threads is in the range 9.degree. to 20.degree., preferably 11.degree. to 16.degree.; the crest portions (20) are substantially straight and intersect the abutting flank (16) portions at a well defined edge (30); the non-abutting flanks (18) have a flank angle which is considerably greater than that of the abutting flanks (16); the flank angle of the non-abutting flanks (18) is in the range 50.

Abstract: A deflection wedge is positioned in a long horizontal drill hole by securing it with a shear pin to an extension on a drill string. The extension is turned independently of the drill string to enable a droparm mechanism to actuate a trigger which stops rotation at a predetermined orientation. Rotation is effected by means of a piston-operated rifle bar mechanism. The piston is actuated by passing drilling fluid down the drill string. The trigger causes a valve to be closed to lock the piston hydraulically in position and thus prevent further rotation. The wedge is now secured by axial pressure on the drill string.