Abstract: A tunnel is constructed by progressively cutting away a predetermined depth of rock from a face using rotary diamond saws. Slots are cut into the face (12) at an acute angle to the face such that first slots intersect second slots to detach blocks from the face. In one embodiment, the cutter (29) is mounted on a slide which can traverse an elongate guide 26. The guide is carried on an arm (24) which can swivel about its own longitudinal axis. A series of angularly spaced slots are cut into the face through 360.degree. with alternate slots being cut at opposite acute angles to the face so that they intersect. A cylindrical tunnel is produced.

Abstract: The apparatus comprises a continuous looped belt (10) having an upper run (11) for carrying a load and a return lower run (12). A single cable (100) is arranged over numerous pulleys to define two spaced parallel upper runs of cable (101) and two spaced parallel lower runs of cable (102) which support the belt runs (11, 12). The belt is broader than the spacing between the spaced runs of cable and seats on top of the cable. A cross-over arrangement (110) provides for the cable to form two identical and parallel cable portions defining the cable runs. All pulleys in one portion are mirrored by co-axial pulleys in the other portion, so that, at any point, the tension in one cable portion is equal to that in the other portion. A double drive roller arrangement reduces scuffing of the cable, so that the whole system substantially reduces wear of the cable.

Abstract: A continuous belt (14) has upper and lower runs (14a, 14b) and is supported by upper and lower runs (23a, 23b) of steel ropes (23) carried and driven by roller (12, 13). The ropes (23) are supported on wheels (22) carried by a frame (11). Rollers (30) invert the lower run of the belt and lead it onto the lower run of the ropes. Magnetic members (50) are secured to the belt and hold the belt relative to the ropes to inhibit relative movement and reduce wear.

Abstract: A continuous belt (14) has upper and lower runs (23a, 23b) of continuous ropes (23) carried and driven by end rollers (12, 13) and intermediate wheels (22). To allow the lower run (14b) of the belt to be supported by the lower run (23b) of the ropes, the lower run of the belt is laterally diverted from below the lower run (23b) of the ropes and re-diverted back onto the lower run of the ropes by rollers (30) in the region of one end roller (12). The lower run of the belt is again diverted laterally and re-diverted below the lower run (23b) of the ropes adjacent the other end roller (13). In another embodiment, the belt (114) is twisted while the lower run of the ropes (123) is vertically diverted to allow space for the twisting of the lower run of the belt below the upper run of the belt, so that lateral movement of the belt beyond the normal confines of the conveyor arrangement is avoided.

Abstract: An improved friction roller including arcuate sections applied to an external surface thereof, the sections configured to receive and engage a magnetic flexible element such as a cable, and including a magnetic field generating coil means for attracting the cable to the arcuate section and thereby to the frictional roller.

Abstract: A scraper chain conveyor with conveyor pans defining a bend round which flight bars are guided in the general plane of the conveyor is provided at the outside of the bend with an auxiliary conveying unit comprising two spaced apart sprockets rotatable about upstanding axes, a line joining the axes being parallel to a tangent to the bend at least when the auxiliary conveying unit is in use, at least one endless auxiliary chain trained round the sprockets, and means for driving the auxiliary chain in a direction such that its chain run adjacent the scraper chain conveyor moves in the direction of feed of the scraper chain conveyor.

Abstract: According to the present invention an agricultural machine for forming a round bale of windrowed fibrous material comprises a displaceable chassis carrying spaced apart side plates defining the width of a bale-forming chamber, a pick-up device located towards a forward end of the chassis and adapted to pick-up fibrous material from the ground and to discharge the fibrous material on to a carrying surface, which extends generally horizontally, of a first, fixed position belt conveyor defining the bottom of the chamber, and having a head end adjacent the pick-up device and a return end remote from the pick-up device, and serving to carry the fibrous material away from the pick-up device, and a plurality of additional belt conveyors each having an active surface adapted to co-operate with the carrying surface of the first, fixed position belt conveyor in the forming of a bale by the rolling of fibrous material, at least one of the additional belt conveyors being movable by having one end pivotably mounted, so th

Abstract: The invention relates to a conduit length to be joined in use to adjacent ends of similar conduit lengths to form an electrical power supply conduit when housing one or more electrical conductors, for the supply of electrical energy to electrical machines, e.g. a mining machine adjacent the conduit, the conduit length being generally of "U" section and internally lined with a seal of flexible material having a corresponding "U" shaped cross section, upper ends of the "U" arms of the conduit each carrying rigid locating means each housing an elongate displaceable sealing means, the two sealing means abutting one another so as to normally close an elongate aperture of the conduit length.

Abstract: A gearhead for a shearer type mining machine comprising an elongate arm pivotally attachable at or about its mid-position to a shearer type mining machine to provide an arm pivot axis extending laterally with respect to the longitudinal axis of the arm, to one or each end of a mining machine, the arm carrying at or towards each end a spiral vane cutting drum, the adjacent drum peripheries being spaced apart to define a nip and the drums being rotatable about axes parallel to the arm pivot axis and being contra-rotatable, the vane or vanes of one drum being of opposite hand to the vane or vanes of the other drum. Mineral loading means is located within the nip provided by said drums, said mineral loading means may be in the form of an auger, a cowl, a paddle chain, or some other type of transporting mechanism, for assisting removal of the cut mineral.

Abstract: A self-propelled mineral winning/detaching machine incorporating at least one electric motor and provided with electrical pick up means movable, in use, with said machine to pick up electrical energy from a stationary conductor.

Abstract: A duct for use with mine equipment is provided with an elongate aperture normally closed by a displaceable sealing means to retain a fluid, under pressure, within the duct, the sealing means, in use, being displaceable by fluid pick-up means carried by a mining machine to convey fluid from the duct to the machine. The invention also includes conveyor trough section provided with such a duct and a mining machine combination.