Abstract: A hydraulic support for underground mining and tunnel construction includes an outer tube to form an upper prop and an inner tube which forms a lower prop and is received in the outer tube to define a pressure chamber. A footpiece is secured to a lower end of the inner tube. Provided on the upper end of the inner tube is a piston which is sealingly guided along the outer tube as pressure fluid is admitted into the upper prop. Disposed inside the lower prop at a location below the piston is a valve block for introducing pressure fluid into the pressure chamber, with a pressure tube connecting the valve block with the piston to thereby define a constant distance of the valve block to the footpiece.

Abstract: The advance of a mining front in longwall mining is effected by a process in which sensors measure the displacement of displacement cylinders coupling the linked prop elements to the linked conveyor elements with their respective cutters. A computer generates a baseline represented by the actual prop line as a starting point and the conveyor elements and cutters are then advanced all along the mining front via the displacement cylinders. The sensors input the respective displacements into the computer so that an actual conveyor line is determined in the computer and serves as the baseline for after-drawing of the prop elements via the cylinders. The new prop line calculated by the computer then forms the baseline for further advance and the advance can be controlled to ultimately align the conveyor elements along the conveyor line corresponding to a setpoint line defined by the computer and parallel to the original baseline.

Abstract: The pressure measuring device has a housing in which a pressure chamber is located in a pin extending freely in the interior of the housing from a base. The pressure chamber wall is deformable elastically under an applied pressure. In the free end portion of the pin a magnetoresistive sensor is mounted which is moved with the chamber wall in a displacement occurring because of pressure changes in the chamber and thus is displaced relative to a permanent magnet. The magnet is mounted slightly transversely in the end portion of a compensating sleeve which surrounds the pin with wall contact. The change of the magnetic field at the sensor on displacement causes a proportional resistance change of the sensor so that an electrical signal proportional to the pressure change is generated which is a measure of the pressure. An amplifier for the signal from the magnetoresistive sensor can be mounted inside the housing adjacent the permanent magnet or the magnetoresistive sensor.

Abstract: In a hydraulically operated unit, particularly a prop for a support in an underground excavation, a thin-walled tubular jacket is pressed on an inner element which is movable in an outer tubular element so that the tubular jacket has an inner diameter which is determined with a substantial undersizing relative to the outer diameter of the inner element, and the tubular jacket is clamped on the inner element with exceeding of the flow limit of the inner element and only in a plastic expansion condition which exceeds with a reliable distance and elastic deformation region of the tubular jacket and with a sufficient residual springing part.

Abstract: A peripherally flexible arch for propping rock structure for mining tracks, tunnels or the like is comprised of a plurality of partially overlapped elongated segments, each of which has an end portion extended toward the rock structure, a bottom portion opposite to the end portion, and a lateral flange offset from the end portion laterally and in the direction toward the bottom portion. Clamping devices are arranged at the ends of the overlapping regions of the segments to clamp the segments to each other. The end portion of each lower segment is inserted into a groove formed between the end portion and the flange portion of each upper segment at the side of this segment facing away from the rock structure. Each clamping device has a hook engaged in a groove formed between the end portion and the flange of the upper segment at the side of this segment facing toward the rock structure.

Abstract: A method of and an arrangement for loosening, loading and transporting of stratified minerals includes a single continuously rotating and forceably guided pulling organ, a plurality of loosening elements integrated in the pulling organ in its working run extending in a longitudinal direction of a longwall, and a plurality of transporting elements also integrated in the same single pulling organ at its transporting run located behind the working run at a back filling side, wherein the loosening elements perform loosening and loading functions, whereas the transporting elements perform the transporting functions in an opposite longitudinal direction of the longwall.

Abstract: A shut-off valve has a sealing cone which in a closed position of the valve abuts against a conical sealing seat and is formed as a part of a cylindrical throttling piston, a sealing surface of the sealing seat cooperates at its one end with a cylindrical receiving opening for the throttling piston, and the outer diameter of the throttling piston is selected with respect to the inner diameter of the receiving opening so that a throttling gap is formed between the receiving opening and the the throttling piston.

Abstract: A clamping device for connecting a number of shaped, elongated, flanged through sections of a support structure to each other includes an upper stirrup, the flanges of which are supported on the flanges of the upper through section, a lower stirrup positioned to support the flanges of the lower through section, and clamping bolts extended through the openings in the flanges of the stirrups and the through sections and tightened with nuts. The head of each bolt has supporting projections provided with convexly curved portions which are engaged in the flanges of the upper stirrup in a form-locking fashion.

Abstract: An arrangement for supplying consumers, particularly mobile consumers, with pressure fluids such as pressure air or pressure liquid, particularly in underground excavations, has a composite rail track for guiding a pressure fluid, a plurality of nipples arranged at a predetermined distance from one another in the longitudinal direction of the rail track, and at least one fluid withdrawing unit which cooperates with the nipples to open the latter and has a length selected with respect to the distance between two neighboring nipples so that one nipple is always located in the effective region of the withdrawing unit to be opened by the latter.

Abstract: A rock anchoring arrangement for use in tunnel and mine constructions comprises an elongated anchoring rod insertable in a bore formed in a rock formation, and a supporting plate arranged in contact with the rock formation at the open end of the bore. The anchoring rod includes a leading end portion fixable at the bottom of the bore, a trailing end portion fixable at the open end of the bore, and a smooth intermediate portion of a cross-sectional area smaller than those of the trailing end portion and the leading end portion. The anchoring rod is fixable by an adhesive within the bore at the leading end portion and at the trailing end portion whereas the intermediate portion is surrounded by an adhesive-repellent material to prevent the sticking thereof to the adhesive.

Abstract: An hydraulic prop utilized for barricades in blasting operations that affords simplified mounting and dismantling and will have minimal functional inefficiency if deformed by the impact of rocks; and it can be made out of unworked pipe of minimal standards. Two specific guide regions disposed on the piston are spaced large enough from each other that comparatively wide tolerances can be achieved between the piston and the cylinder.

Abstract: A wall element for an underground gallery has a W-shaped member which is symmetrical relative to its y-axis and has an axis of gravity coinciding with its x-axis and lying at approximately the center of its side, wherein the thickness of its lateral flange portions, base portions and connecting web portions are selected so that, in relation to used weight per meter, the W-shaped member has a maximum possible moment of resistance relative to the x-axis and a maximum possible bending load capacity in the plastic deformation range, and the W-shaped member has such a profile and such thicknesses of these portions that it has at least approximately equal bending load capacities in the plastic deformation region in two opposite directions along the y-axis.

Abstract: A rock anchoring arrangement for use especially in tunnel and mine constructions involving considerable convergences comprises an anchoring sleeve having a leading and a trailing end as considered in the direction of introduction of the anchoring arrangement into an anchoring bore in the rock formation, an anchoring rod having a trailing end portion passing through the interior of the anchoring sleeve and a leading end portion which extends beyond the leading end of the sleeve, a mounting plate arranged at the trailing end of the sleeve and engaging the rock formation around the open end of the bore, and a drawing die secured to the sleeve at the leading end. The anchoring sleeve and the anchoring rod are both retained in the bore by a body of a hardenable material, such as an adhesive, in which the sleeve and the leading end portion of the rod are embedded. The leading end portion of the rod has a smaller diameter than the trailing end portion so that a transition region exists between these portions.

Abstract: A chain bucket conveyor for an underground excavation has a substantially U-shaped forward conveyor part at the side of the sole and open toward a roof, a return conveyor part at the side of backfilling and closed in a substantially channel-like manner, wherein the return conveyor part is normal to the forward conveyor part, and means for transporting the chain from one to the other of the conveyor parts and including actuating stations, a rotary chain wheel having chain pockets and arranged at the actuating stations rotatable about an axis which extends toward the roof and backfilling and is located in a vertical plane transverse to the longitudinal direction of the conveyor, and a conical surface narrowing toward the roof and having an axis coinciding with the axis of rotation of the chain wheel.

Abstract: An arrangement for erecting a columnar supporting element of a hardenable flowable material, for a roof of an underground excavation, has a hollow casing for filling with a hardenable flowable material and is composed of two telescopable casing portions each composed of two open-end semi-circular sections, an element for holding the upper casing portion in contact with the roof of an underground excavation and arranged adjacent to the casing, and elements for connecting the semi-circular sections of at least the lower prop casing portions with one another so as to be pivotable about a longitudinal pivot axis which is parallel to the longitudinal axis of the prop casing, and locking the same with one another.

Abstract: A method and a system are disclosed for supporting an overburden. A single-section or telescoped multi-section longitudinally slit prop casing of light sheet material such as cardboard or metal has a fabric bag installed in it. When the casing is erected the bag is filled with a slurry of hardenable substance which, upon hardening, forms in the bag a column which supports the overburden. The casing may be left in place or it may be removed for re-use.

Abstract: Roofs of underground excavations are supported by forming sheet-material elements into tubes whose diameter can be varied by changing the overlap between the longitudinal edges of the rolled-up sheet material, standing the tubes upright to bear against the roof and the floor of the excavation, and filling them with hardenable material in flowable condition which, after hardening, will form a roof-supporting column.

Abstract: A mine prop provided with an overpressure valve of large flow-through section which opens when excessive forces suddenly act on the prop to discharge pressure fluid from the interior of the prop. The overpressure valve comprises a hollow cylindrical housing forming at one end a valve seat communicating with the fluid-filled inner space of the prop and a valve member axially guided in the housing for movement between a closed position engaging the valve seat and an open position. The fluid-filled space of the prop communicates with channels leading to the outside of the prop. The valve member is normally maintained in the closed position by a gas pillow under high pretension confined in a pressure space delimited peripherally by the wall of the valve housing and at opposite ends respectively by the valve member and a plug fluid tightly mounted in and closing the other end of the housing.

Abstract: A shield timbering frame for timbering mines adjacent a mining face, comprises a horizontal floor-engaging skid and a breaking shield extending obliquely over the skid which is connected to the skid by a pair of longitudinally spaced, lemniscate guide rods. A roof cap member has an inner end which is pivoted to the upper end of the breaking shield and it is also braced by a piston and cylinder combination which is articulated to the breaking shield intermediate the length thereof and to the roof cap intermediate its length. At least one hydraulic ram is mounted on the skid and is engaged with the roof cap between the connection of the roof cap to the breaking shield and the connection to the additional support. The hydraulic ram is madeup of at least three telescopically interengageable extensible and retractable parts and includes pressure valve means to provide a substantially equal support pressure on the roof cap in various positional orientations of the roof cap.

Abstract: A timbering device connected to a longwall conveyor disposed toward the mining face of an excavation for progressively timbering frames from the gobbing side toward the mining face side comprises first and second skids which are adapted to be shifted over the floor. The guide piece is pivoted to one of the skids adjacent the gobbing side thereof and it has a guide slot extending toward the mining face. A push rod has one end connected to the longwall conveyor and an opposite end having a slide portion which is slidable in the guide piece guide slot. A thrust drive piston has a gobbing side end pivotally connected to the slide piece portion of the push rods and has an opposite mounting face end which is pivotally connected to a bracket carried under one of said skids. The sliding plane control device is carried by the pusher rod.