Abstract: A mine roof support unit has a floor sill, a roof cap supported above the floor sill by a pair of inclined hydraulic props, and control apparatus for controlling load-bearing capacity of the props. The inclination of the props relative to the vertical increases as the props are retracted. The control apparatus comprises a pressure-relief valve for limiting the pressure of the hydraulic fluid supplied to the hydraulic props. The pressure-relief valve has a closure member which is biased towards its closed position by a spring. The spring is backed by an abutment member which constitutes a setting device for adjusting the biasing force of the spring, thereby controlling the operating pressure of the pressure-relief valve, and hence the load-bearing capacity of the props.

Abstract: The specification discloses a method of, and apparatus for, winning mineral material from the pillars left by the bord-and-pillar mining process. An arcuate longwall face, which may be convex or concave, is formed along a row of pillars. The mineral material in the pillars is won by mechanical winning means such as a plough, the pillars in each row being won in a non-uniform manner. Some of the mineral material won from the longwall face may be used to fill the stalls left between the pillars behind the longwall face.

Abstract: A hydraulic coupling device is provided for connection to a multi-line hose constituted by a plurality of hydraulic conduits bunched together. The coupling device comprises a casing, a plurality of plug pins housed within the casing, and a holder for holding the plug pins. The plug pins are each connectible to a respective conduit of the multi-line hose. The holder is constituted by at least two retaining discs, and each plug pin is provided with two circumferential grooves. The retaining discs are each provided with a respective aperture through which one of the plug pins passes. Portions of the retaining discs adjacent to the apertures can be tightly engaged within the grooves in the plug pins, by being radially displaced and/or rotated relative to one another. In this way, the plug pins are axially fixed relative to the retaining discs.

Abstract: A hydraulic coupling device is provided for connection to a multi-line hose constituted by a plurality of hydraulic conduits bunched together. The coupling device comprises a casing, a plurality of plug pins housed within the casing, and a retaining disc for holding the plug pins. The plug pins are each connectible to a respective conduit of the multi-line hose. Each of the plug pins has a circumferential groove, and the plug pins are held against axial movement in radial slots in the retaining disc. Each of the radial slots has a first portion whose width is greater than the maximum external diameter of the associated plug pin, and a second portion whose width is less than that of the maximum external diameter of the associated plug pin, but which is greater than the diameter of the circumferential groove in that plug pin.

Abstract: A mineral winning machine is moved back and forth along a mineral, e.g., coal, face to win mineral by a combination of cutting and wedging actions. To effect this winning mode, the machine has at least one cutting device with a cutting disk rotating in front of a frusto-conical wedging body which revolves in an eccentric manner to detach the mineral previously backcut by the disk. The wedging body and the cutting disk are driven by separate concentric drive shafts, preferably with variable speed regulation with the disk rotating faster than the wedging body. In an alternative construction, a cutting chain equipped with both cutting and wedging tools in differential relationship is circulated and engages the mineral face.

Abstract: A mineral mining installation comprises a mechanical mining machine (such as a plough or a shearer) and a hydraulic winning machine. The hydraulic winning machine has a plurality of high-pressure nozzles and a high-pressure pump for supplying the nozzles with high-pressure water (or other hydraulic fluid). Means are provided for driving each of the two winning machines independently of the other along a mineral face. This permits the mechanical winning machine to operate at its optimum, high speed rate without interference from the slower moving hydraulic winning machine. The pump is preferably a multiple radial-piston pump powered by an electric motor. Both electric power and water may be supplied to the hydraulic winning machine via pick-up arms on the machine and supply channels extending along the face.

Abstract: In a mineral mining installation employing a series of shifting rams for advancing a scraper-chain conveyor provided with a guide for a mining machine, a control system is used to provide a succession of small fluid doses to the rams. Control signals, preferably remotely generated, serve to actuate local valves to cause a selected one or group of piston and cylinder metering devices to alternately accept and expel pressure fluid from a working chamber. In this way a pre-determined volume of pressure fluid can be transferred to one or more of the rams to effect the shifting advancement. This volume of pressure fluid is made up from a succession of small fluid doses each a small fraction of the desired shifting distance so that by repeated cycles of the device or devices the ram or rams associated therewith can extend in fine defined increments.

Abstract: In a mineral mining installation employing a series of shifting rams for advancing a scraper-chain conveyor provided with a guide for a mining machine a control system with a central control station for transmitting control signals. The control signals serve to actuate local control valves, possibly in time dependence, to cause a selected one or group of metering devices to transfer a pre-determined volume of pressure fluid to one or more of the rams to effect said advancement. This volume of pressure fluid is some fraction of the total capacity of the ram or rams in question so that by repeatedly transmitting control signals the device or devices can perform successive cycles of operation to thereby cause the ram or rams associated therewith to extend in defined increments.

Abstract: In a mineral mining installation employing a series of shifting rams for advancing a scraper-chain conveyor provided with a guide for a mining machine a control system with a central control station for transmitting control signals. The control signals serve to actuate local control valves, possibly in time dependence, to cause a selected one or group of metering devices to transfer a pre-determined volume of pressure fluid to one or more of the rams to effect said advancement. This volume of pressure fluid is some fraction of the total capacity of the ram or rams in question so that by repeatedly transmitting control signals the device or devices can perform successive cycles of operation to thereby cause the ram or rams associated therewith to extend in defined increments.

Abstract: A device includes a spring for biasing a door or other similar structure into a closed position and a fluid medium for damping movement of the door. The damping effect is achieved by compelling the fluid to pass from one chamber to another within a housing of the device by changing the volumes of the chambers, the spring itself being used to bring about the change in volume.