Abstract: A hydraulic support monitoring a support pose in real time based on an inertia measurement unit (IMU) and a detection method thereof. In the hydraulic support, IMU sensors are separately mounted on a roof beam, a rear linkage, and a base, and an auxiliary support pose monitoring system is disposed. Each IMU sensor measures movement states of the roof beam, the rear linkage, and the base of the support in real time, and the support pose monitoring system processes the movement states to monitor a support pose of the hydraulic support in real time. Especially, it can be technically determined whether the hydraulic support is adequately lowered, moved or raised, thereby effectively reducing the labor intensity of workers and improving the working efficiency of the hydraulic support.

Abstract: Methods and equipment have been developed that combine the use of continuous miners, flexible conveyor trains, and longwall mining techniques to provide flexible and efficient removal of resources from subterranean formations. Some systems for use in a mining operation include: a continuous miner configured to cut material from a face; a plurality of powered roof supports positioned along the face; and a guidance system operable to receive a location signal based on relative location of the continuous miner along the face and to send a control signal to the plurality of powered roof supports positioned along the face.

Abstract: A system for enabling movement of a machine is provided. The system includes a support member provided on the machine. The support member is configured to be in a raised position or a lowered position relative to a frame of the machine. The system also includes an actuation module configured to selectively enable the movement of the machine. The system further includes an enabler valve coupled to the actuation module and the support member. The enabler valve is configured to selectively send a pilot signal to the actuation module based on the position of the support member.

Abstract: A hydraulic circuit for longwall support for use in underground mining for supporting a longwall by means of a plurality of support shields includes in the annular piston line of each cylinder/piston unit a pressure sensor. The pressure sensor, upon reaching a predetermined maximum pressure activates a pressure deviation signal, causes the entire longwall to be depressurized by means of a longwall shut-off valve. The pressure deviation signal is blocked for one of the hydraulic valves against each triggering signal.

Abstract: A method for controlling a longwall mining operation, including a face conveyor, at least one extraction machine, and a hydraulic shield support, in underground coal mining. Using inclination sensors disposed on at least three of the four main components of each shield support frame, such as floor skid, gob shield, support connection rods, and gob-side region of the top canopy, the inclination of the shield components relative to horizontal is ascertained in the direction of step. In a computer, the ascertained inclination data is compared with base data stored in the computer that defines the geometrical orientation of the components and their movement during stepping. From the comparison, a respective height of the shield support frame, at the forward end of the top canopy, is calculated as a measure for the face opening.

Abstract: The shield control device of a longwall shield for carrying out the longwall functions of the longwall shield in the longwall face working in a mine is associated with a distributing device upstream of a group of functional elements. Each of the functional elements of the longwall shield is associated with an exclusive address code word, on the call of which the internal connection between the shield control device and the functional elements depends. The distributing device is arranged in close proximity to the functional elements. The functional elements are valves or sensors.

Abstract: A hydraulic circuit for longwall support for use in underground mining for supporting a longwall by means of a plurality of support shields comprises in the annular piston line of each cylinder/piston unit a pressure sensor. Said pressure sensor upon reaching a predetermined maximum pressure activates a pressure deviation signal, which causes the entire longwall to be depressurized by means of a longwall shut-off valve. The pressure deviation signal is blocked for one of the hydraulic valves against each triggering signal.

Abstract: A shield support for underground mining has a slider and a roof bar between which a ram is arranged, with an inclination detector being provided with which the inclination of the roof bar can be measured.

Abstract: A water system for the admission of pressurized water to spray systems arranged on a powered support assembly for underground mining, having at least one spray system for plow or shearer track spraying and having at least one further spray system for goaf space spraying, canopy spraying and side spraying. A central water line feeds spray nozzles of the spray systems. To increase the operating reliability of the water system and thus of the powered support assembly, the control valves for the spray systems are accommodated in a spray valve block which is provided with a connection for the water line and which can be arranged on the powered support assembly as a unit separated from a hydraulic valve block.

Abstract: A module and related methods of use in drilling a borehole in a face of a mine passage using a drilling element and installing a bolt in the borehole once formed. The module may include a bolt holder for holding a plurality of bolts and a drilling element holder for holding a plurality of different drilling elements. A manipulator moves along an arcuate path between the bolt and drilling element holders to deliver the respective components to a drill head positioned along the arcuate path. The drill head may also slide relative to the mast in two different directions, and includes a drill guide for determining the location of the face to be worked.

Abstract: A longwall support control for controlling the movements of the longwall support units and the advance heading in the longwall of a mine comprises a plurality of control units, of which a separate mining shield control device is locally and operationally associated to each longwall support unit. Each mining shield control device comprises a multi-channel radio transceiver, such that the mining shield control device is in a simultaneous transmit and receive mode with a decentralized operating device for receiving control signals and for transmitting inspection data. The mining shield control devices may be interconnected and each mining shield control device may include an amplifier.

Abstract: A longwall support control for controlling the movements of longwall support units in the longwall of a mine that includes a central control system and a plurality of control units, of which a separate control unit (mining shield control device) is locally and operationally associated to each longwall support unit. The mining shield control devices connect to the central control system and to one another via two bus lines, through which each of the mining shield control devices can be called up for inputting a control command from the central control system or an adjacent mining shield control device. The identical second bus line (parallel bus) permits retransmitting to the adjacent mining shield control device, incoming signals that do not store a code word assigned to the respectively addressed mining shield control device.

Abstract: The invention relates to a valve 120, especially a check valve, for hydraulic plungers (3) of shield-type support frames in underground mining with a valve housing 121 and a switchable valve insert received therein, connections 126-129 for high pressure lines connected to the cylinder chamber and/or the annular space of the hydraulic cylinder 3, and at least one connection 30 for an additional unit such as a pressure relief valve, a pressure sensor, and/or a pressure display. The valve housing 121 can be mounted to the hydraulic cylinder 3, and in the mounting stage, the connections 125-129 on the valve housing 121 extend axially parallel to the axis of the hydraulic plunger 3. According to an advantageous further embodiment, the valve housing can be provided with at least one fastening means for an extension housing 40 that can be mounted in a releasable manner to at least one side wall 22B thereof for additional hydraulic functions of the shield-type support frame (see FIG. 2).

Abstract: A longwall support control for controlling the movements of longwall support units in the longwall of a mine that includes a central control system and a plurality of control units, of which a separate control unit (mining shield control device) is locally and operationally associated to each longwall support unit. Each mining shield control device comprises a switching element, which permits separating the bus line or lines in the mining shield control device. The mining control devices may also include signal amplifiers. An identical second bus line (parallel bus) permits retransmitting to the adjacent mining shield control device, incoming signals that do not store a code word assigned to the respectively addressed mining shield control device.

Abstract: A hydraulic shield support is disclosed with at least two adjustable-length hydraulic props supporting a dedicated shield, which are connected through a control bank to a hydraulic fluid supply and borne on base shoes, and to which a pressure in excess of the pressure of the hydraulic fluid may be applied in the set condition of the shield support. In order to provide almost any pressure level at each shield support at a deep face in a simple way, the shield support has at least one pressure intensifier located in a hydraulic pipe system between the hydraulic fluid supply and the hydraulic props, with an oscillating intensifier piston in the form a differential piston effecting the increase in pressure. The low pressure inlet of the pressure intensifier is connected to the setting pressure pipes upstream, and its high-pressure outlet downstream, of a hydraulically-releasable non-return valve.

Abstract: A controller is disclosed for control operations in underground mining, especially for controllers to control support shields. The controller utilizes a central unit with a microprocessor and assigned, programmable memory devices for the storage and processing of software as well as a connector unit with connectors or circuits for communication between the controller and other controllers and/or actuators, sensors or the like, that are to be controlled with the controller. Both the central unit and the connector unit utilize a modular design. A collection of modules with different performances and/or functionalities are provided for both the central unit and the connector unit to form the hardware of a controller. The modules can be combined with one another and coupled together according to a modular concept.

Abstract: Embodiments of the present invention are directed to a method and apparatus for safety protection control of temporary roof support. In one embodiment, a temporary roof support has a load sensing member. In another embodiment, a beam structure of temporary roof support is supported by a load sensing pin. Strain gages are installed within the pin to measure the load placed upon the pin. An unusually high load being sensed by the pin indicates that the roof has fractured and the temporary roof support is supporting loose rock. In one embodiment, when an unusually high load is measured at the pin, the temporary roof support controls at the front of the machine are disabled. A second set of remotely located temporary roof support controls remain operative. In one embodiment, the second set of controls is located at the rear of the machine.

Abstract: A method and device for drilling and setting adhesive anchor bolts close to the mine face during the cutting operation of a tunneling or mining machine which is capable of being displaced on a traveling mechanism and includes a cutting cylinder or cutting head rotationally mounted on a cantilever arm pivotable in a vertical direction, and optionally in a horizontal direction. The method is carried out in a manner where the substantially horizontal forward movement of the cantilever arm at break-in cutting is detected and a signal is generated during break-in cutting to block commencement of a working cycle for drilling and anchoring. A controller (16) for excavation of material on the mine face is networked with a controller (15) for actuation of the anchor drilling and setting device (10) via radio, electrical or optical lines (17).

Abstract: A control system for a mining machine which moves in passes across a seam to be mined using absolute coordinates is disclosed. The machine is carried on rail and co-ordinates of the rail are measured along the length of rail. The rail is then moved to a new position for a next pass, and the distance of moving is determined from the co-ordinates previously measured. By knowing the co-ordinates, the rail can be moved to assume a desired profile, so that a desired profile of the seam can be achieved on the next pass. Co-ordinates of the up and down movement of a shearing head can also be measured and stored with the co-ordinates along the rail to provide a profile of the seam being cut, and so that on a next pass the intended position of the shearing head can be predicted and moved accordingly.

Abstract: A mining control system for adjusting the advance of the working tools of a mining machine with respect to working depth and/or working height connects to a detection device that is for recognizing the rock being mined and is carried along by the mining machine. A central command station connects by radio to the detection device of the mining machine. The mining control system comprises a plurality of radio receivers arranged in spaced relationship along the longwall, as well as a comparator, which is used for comparing the intensity of the radio signals received by the individual radio receivers and for retransmitting only the strongest of the radio signals to the central command station for generating the command signals for controlling the advance of the mining tools. It is also possible to transmit the radio signals received by each radio receiver to adjacent radio receivers. A separate comparator is associated to and controls each radio receiver.

Abstract: Hollow-ground surfaces are simultaneously formed along opposite sides of a knife blade blank by passing the knife blade blank between a pair of grinding wheels. The grinding wheels carry grinding belts about idler pulleys. The idler pulleys are adjustable toward and away from the respective grinding wheels to adjust belt tension and to accommodate different sizes of grinding belts. The angularity of the idler pulleys relative to the grinding wheels is likewise adjustable such that planes passing through the idler wheels and grinding wheels are angularly adjustable relative to one another enabling the grinding belts to run true about the grinding wheels.

Abstract: Stable, perfumed, highly acidic liquid compositions are disclosed which comprise a source of active oxygen, a surfactant and a cyclic terpene/sesquiterpene compound (e.g. eucalyptol). Said compositions are particularly suitable to clean hard surfaces like toilet bowls.

Abstract: A cable mine roof bolt driver is disclosed for rotating a cable mine roof bolt in resin grouted applications. The bolt driver includes a body having a front face and a rear face. A cable receiving bore is positioned within the body extending into the body from the front face. The cable receiving bore is adapted to receive a cable of the cable mine roof bolt therein. A cable engaging device is provided within the cable receiving bore for rotatably engaging the cable such that rotation of the body will rotate the mine roof bolt when the cable engaging device has engaged the cable. A body rotation mechanism is coupled to the body for providing rotation of the body of the bolt driver. The cable mine roof bolt driver of the present invention can be utilized to rotate conventional cable mine roof bolts in resin grouted applications.

Abstract: A yield valve comprises a valve body, a first inlet port, an outlet port, a valve seat, and a valve member movable between a first position in which it cooperates with the valve seat to prevent fluid communication between the inlet port and the outlet port and a second position in which the outlet port is brought into fluid communication with the inlet port. One side of the valve member is subjected to the pressure of fluid at the inlet port to urge the valve member towards its second position. Spring means acts on the other side of the valve member to urge the valve member towards its first position. The valve also has a valve chamber isolated from the inlet port and from the outlet port and a second inlet port for supplying a fluid under pressure to the chamber.

Abstract: A mine roof support having means for monitoring the angles made by the canopy 11 and the base 10 with respect to a datum. The angular information may be gathered in a number of different ways and the information used to control subsequent movements of the support.

Abstract: The control device is adapted to be inserted between the control valves of a pilot device and the pressure-medium consumers (hydraulic prop and hydraulic working cylinder) in an hydraulic self-advancing mine-roof support and is connected to a pressure-medium line and to a return line. The control device comprises a valve block with continuous longitudinal bores for connection to a multiple tubing line leading to the pilot device, the valve block having bores for receiving piloted 3/2-way valves and bores for connection to the directly-controlled working cylinders of the mine-roof support.

Abstract: In a method of mining coal seams using a ploughing cutter, a longwall conveyor extending along the coal face is moved forwards by the extension of self-advancing cylinders, the advance being controlled in dependence on a piston stroke of a respective self-advancing cylinder and being made in individual defined partial strokes using travel-measuring signals generated at each partial stroke. The distance covered by the partial strokes corresponds to the preset depth of cutting and is increased by an amount sufficient to compensate an average mechanical clearance at the pivot points of the self-advancing cylinders. In addition, a defined face line is fixed with respect to a center of rotation on the side of a main or auxiliary drive of the cutter so as to form a straight line through the center of rotation, the straight line being pivoted through an angle <90.degree. so that a circular segment is mined.

Abstract: A method of working coal seams to a defined preset cutting depth during ploughing with a cutter, a face conveyor moving along a face behind the cutter being advanced by the defined preset cutting depth and this advance being made by extension of self-advancing cylinders pivotally attached at one end to the face conveyor and at the other end to face supports disposed parallel to the face conveyor. The advance is controlled in dependence upon the piston stroke of the self-advancing cylinders, carried out in dependence upon individually defined partial strokes corresponding to the preset depth of cutting. After a predetermined maximum total piston stroke has been reached, the face support connected to the respective self-advancing cylinder is automatically disengaged, advanced by the maximum total piston stroke and then re-set (self-advancing process).

Abstract: A cutting machine for mining minerals from a seam thereof, the machine executing reciprocal movements parallel to the face of the seam and being provided with switches for generating signals indicative of the direction of movement of the machine for controlling the removal of protective bumpers on support structures located forwardly of the machine and for moving support structures against the face of the seam and relocating bumpers rearwardly of the machine.

Abstract: A mine door system including a door frame to be installed in a mine passageway to define a generally rectangular doorway. A mine door is defined by a pair of generally rectangular door leafs which are hinged on the door frame at opposite sides of the doorway for swinging between an open position to permit passage through the doorway and a closed position in which the door leafs are generally coplanar and close the doorway. The door leafs are so dimensioned that there is a substantial vertical gap between the door leafs when they are closed to accommodate convergence of side walls of the passageway. A relatively wide vertical sealing flap is secured to one of the door leafs for overlapping a face of the other door leaf when the door is closed for covering the gap between the door leafs.

Abstract: A process for automatic ploughing during the winning of coal and the like in a longwall working with a hydraulic advancing lining with individual support units controlled by an electro-hydraulic control means. A plough guide is shifted automatically in stages by the plough cutting depth after passage of the plough by means of rams allocated to the support units and the support units are automatically shifted up as a function of the plough movement. The support units are positioned in support groups of which a plurality in each case are offset relative to one another in the shifting direction by the plough cutting depth and/or a multiple thereof. During the ploughing run only those support units of which the residual stroke of the shifting rams still available for shifting the plough guide is smaller than the plough cutting depth are automatically re-located in each case at a distance behind the passing plough.

Abstract: A through flow coupler comprises two parts having intercommunicating passages therein so that fluid can flow through the two parts. A sealing member provides a fluid tight seal between the two parts when the two parts are held together in a sealed condition. A pressure sensitive device, which may comprise a frangible ring, holds the two parts in the sealed condition when the fluid pressure within the passages is below a certain value and allows the two parts to move relative to one another to a pressure relief condition so that fluid can escape from the passages when the fluid pressure within the passages exceeds said certain value. Also, mutually co-operable members, e.g. flanges, are provided to prevent total separation of the two parts when the pressure sensitive device allows the two parts to move relative to one another.

Abstract: A mining apparatus of the type in which a mining machine excavates a mining face, especially a coal face in a subterranean mining application, and has a plurality of emitters of electromagnetic waves of different character diverging toward receivers on the individual walking props. The walking props are provided with a control unit which, in response to leading and trailing zones of the respective magnetic beams and/or an overlap region of the two beams, causes the advance of the walking prop as the mining machine travels past it to follow the excavation of the mining face.

Abstract: A mine roof support comprises a canopy, a base section, hydraulic props for raising and lowering the canopy relative to the base section, a hydraulic valve for supplying hydraulic fluid under pressure to the props via a check valve, and a yield valve connected across the check valve. The yield valve has a valve member movable between a first position in which it co-operates with a valve seat to prevent the release of fluid from the props via the yield valve and a second position in which fluid can be released from the props via the yield valve. One side of the valve member is subjected to fluid pressure downstream of the check valve to urge the valve member towards its second position and the other side of the valve member is acted upon by a spring device to urge the valve member towards its first position.

Abstract: An electro-hydraulic control system for a mineral mining installation has a plurality of control units (4) sub-divided into operational groups (I, II, III) with associated roof supports. Each group has its own power source (5) and power at an intrinsically safe level is provided to each of the groups independently of and in isolation from the other groups. The control units (4) are interconnected via a system data bus (13,14) in the form of conductors of multi-core cables which also carry the electrical power. A further data bus (20) independent of the system bus (13,14) is coupled to some of the units of the groups.

Abstract: An electro-hydraulic control system for a mineral mining installation has a series of valve blocks, each contain a number of valves which are operated in dependence on electrical signals to cause hydraulic appliances of roof supports to operate. To allow emergency operation, when there is a power failure or when the control system fails or is otherwise inoperative, further manually operable valves are connected by a flexible, multi-core connecting cable to the valve block of the associated support. The emergency control valves can operate hydraulically controllable direction control valves of the control system and by-pass the electrical controls. The support can then be controlled purely hydraulically, at least in its main functions, using the emergency device.

Abstract: Apparatus for transmitting data relating to a mining machine in a longwall mining operation, comprising a data collection device mountable on a mining machine for collecting data relating to the machine, a data transmission device also mountable on the mining machine for transmitting the data in the form of a remote signal, and a plurality of receiving devices each mountable on one of a plurality of mine roof supports past which the machine is arranged to travel. The apparatus also includes a data conveying device for conveying the data away from the mine roof supports.

Abstract: A hydraulic temporary mine roof support cylinder is disclosed. The support cylinder includes an outer housing and a coaxial intermediate housing member and inner cylinder. A downwardly extending piston is provided between the outer housing and intermediate housing member. In addition, a sleeve piston is provided within the inner cylinder while an inner piston rod is extensible from the sleeve piston. Controls are provided for independently operating the lower cylinder and the upper cylinders. Additionally, a sequence/check valve ensures the timed operation of the upper cylinders. Due to the present design, each of the cylinders may be collapsed within the outer housing.

Abstract: A control means for hydraulic self-advancing support units for underground working, comprising at least one electrohydraulic control device comprising an electric circuit for energizing electromagnets which actuate hydraulic valves, a command keyboard connected to the energizing circuit, a display connected to the energizing circuit and two multipole connectors for connecting the control device to respective adjacent devices, the multipole connectors being connected to one another and to the energizing circuit by electric lines inside the control device, characterized in that the energizing circuit is substantially made up of a CPU control sub-assembly, a keyboard and display sub-assembly, and a magnet control sub-assembly, these sub-assemblies being interconnected by a common bus line, the line connection between the plug-in connectors comprises at least one flexible printed circuit board connected by at least one ribbon cross-connection to one of the three sub-assemblies, and the magnet control sub-assembly

Abstract: A shaking control unit for a hydraulic cylinder, wherein a first predetermined pressure is admitted to the piston space of the cylinder through a first hydraulic line. A three/two-way valve connects in its zero position a second hydraulic line to a return tank, the second hydraulic line being connected to the first hydraulic line through a check valve. A first control line leads from the first hydraulic line to a first control area of the three/two-way valve. A second control line leads from the second hydraulic line to a second control area of the three/two-way valve. The three/two-way valve is constructed in such a way that, when the pressure in the first hydraulic line reaches a second predetermined pressure which is greater than the first predetermined pressure, the three/two-way valve switches and connects the first hydraulic line to the second hydraulic line. If the piston of the hydraulic cylinder meets an obstacle, the pressure in the first hydraulic line rises above a certain limit value.

Abstract: A method of electro-hydraulic control of the cutting and self-advancing mine-roof support units in an automated longwall is carried out in dependence on the measured lengths to which the rams pushing the support are extended, with extraction by the cutter occurring in long cuts extending over almost the entire length of the longwall. After each extraction cut, the conveyor is advanced by an amount equal to the depth to which the cutter has cut, and the process of advancing each group is triggered in dependence on the length to which the pushing rams have been extended. The self-advancing roof-support units inserted in the longwall are divided into groups which, depending on the respective state of operation, are moved forward individually and successively, in each case by a preset extension length of the pushing rams.

Abstract: Methods are provided for translating a face support comprising a plurality of support units arranged side-by-side at an initial position. In the first embodiment, a first pair of alternately positioned support units are moved a predetermined distance from the initial position. Next, a second pair of alternately positioned support units are moved the predetermined distance. One of the support units of the second pair is positioned between the first pair. These moving steps are repeated until the entire plurality of support units is moved the desired distance. In the second embodiment, the first moving step is duplicated. Then, a single support unit located between the first pair is moved the predetermined distance. These two moving steps are repeated until all of the support units are moved.

Abstract: A method and device is provided for the moving of a shield-type support trestle 1 having stamps 4, 5 arranged between a roof pressure cap 3 and a lying skid 2, a pushing ram 6 is in the lying skid 2, and control valves 11, 12, 13, 14 for controlling the desired functions of the shield-type support trestle 1. The stamps 4, 5 have an inlet valve 22 and a discharge valve 4. A pressure line 40 is provided between control valve 13 and the pushing ram 6. A valve 51 is provided which is controlled by the pressure in the pressure line 40 and by which interconnects stamp pressure chambers. A manometric switch 48 is arranged on the pressure line 40 and activates an electronic control device 42. In lines 53, 55, and 29 between the stamp pressure chambers and the return line 18, an unlockable reflux valve 54 is provided which is actuated through the electronic control device 42 and the discharge valve 24.

Abstract: A pressure-relief valve device employs a connector welded to the base of mining equipment equipment such as an hydraulic prop, so as to communicate with the pressure fluid in a working chamber thereof. A housing is screwed into the connector and the connector has an outflow passage leading to the surroundings. A valve composed of a fixed valve seating and a movable closure member opens and closes communication between the working chamber and the outflow passage. A spring holds the valve closure member on the seating. The valve closure member is slidably guided on part of a tappet subjected to spring force. The tappet has a piston exposed to the pressure fluid which opposes the spring force. If excess pressure occurs the tappet moves against the spring force and lifts the closure member off the seating. Once the pressure drops the tappet moves back under the action of the spring but the closure member can move more slowly to gently re-establish the valve action.

Abstract: A transducer is placed in a telescopic strut and connected to a roof cam and a floor cam. The cams are pivoted to a roof support and a constant load is applied to the cams by a gas spring. As convergence takes place a transducer in the telescopic strut records the relative movement between the floor and roof and transmits this as an electrical signal for analysis.

Abstract: A shaking control unit for a hydraulic cylinder, wherein a first predetermined pressure is admitted to the piston space of the cylinder through a first hydraulic line. A three/two-way valve connects in its zero position a second hydraulic line to a return tank, the second hydraulic line being connected to the first hydraulic line through a check valve. A first control line leads from the first hydraulic line to a first control area of the three/two-way valve. A second control line leads from the second hydraulic line to a second control area of the three/two-way valve. The three/two-way valve is constructed in such a way that, when the pressure in the first hydraulic line reaches a second predetermined pressure which is greater than the first predetermined pressure, the three/two-way valve switches and connects the first hydraulic line to the second hydraulic line. If the piston of the hydraulic cylinder meets an obstacle, the pressure in the first hydraulic line rises above a certain limit value.

Abstract: An electro-hydraulic control system has a valve unit allocated to a roof support (support shield, support trestle or the like) and equipped with electromagnetic valves. The unit is controlled by a control unit via a cable which includes two current supply leads serving as a common current supply for all the electromagnetic valves and at least one data bus through which an actuator connected with the valve unit is actuated from a microprocessor of the control unit. The actuator itself consists preferably of a shift register through which all the electromagnetic valves can be actuated.

Abstract: A mining apparatus for utilization in recovering coal includes a series of four cooperating legs: a right fore leg, left fore leg, right rear leg and left rear leg. Each leg is formed from a box-like shield. An inflatable bag is provided in each leg. When a particular bag is inflated, the bag expands extending the leg between the floor and roof of the mine. When deflated, the leg retracts. A series of hydraulic rams connect the legs together. These rams may be expanded and retracted as desired to move the support legs relative to one another. In this way the apparatus may be moved in substantially any direction about a 360.degree. arc. A microprocessor controller controls the operation of the apparatus. In accordance with further aspects of the invention, a number of mining apparatus of the type described may be connected together in series to form a line for roof support.

Abstract: A mining system comprises a laterally deflectable segmented conveyor extending longitudinally along a longitudinal face from which material is to be cut, a mining machine displaceable longitudinally along the conveyor and engageable with the face to cut material therefrom and deposit in the conveyor, and a longitudinal succession of support frames each having a respective actuator connected to a respective segment of the conveyor and each also having a respective a respective retractile roof-engaging flap. The process of this invention comprises bracing the frames and conveyor in a safety zone immediately adjacent the mining machine against the roof with their flaps retracted. The machine is advanced in the safety zone while cutting the face in the safety zone, and the flaps of the frames in a zone immediately downstream of the safety zone are sequentially retracted and the flaps of the frames in a zone upstream of the safety zone are sequentially advanced.

Abstract: A data transmission/reception system usable for bi-directional data transmission in electro-hydraulic control systems between two adjacent supports of a mine installation which each have their own transmitting and receiving stations in a control unit. Bi-directional data exchange takes place via a single wire data bus which is used for simultaneous transmission and reception and forms the summation point for adding the transmitted signals from two transmitters. Each transmitting and receiving station is provided with a subtraction circuit connected to a receiver of the respective transmitting and receiving stations and to which the transmitted signals from its own transmitter are supplied in each case at the subtraction circuit input. The other input of the subtraction circuit is connected to the bi-directional data bus.