Abstract: The apparatus for removing stratified outcropped minerals and for transporting these minerals parallel to the mining face or breast comprises a digging portion and a conveyor portion as well as a chain conveyor guided positively in them with digging tools and carrier members. The digging portion and the conveyor portion are assembled together from a plurality of pan-like members. Each pan of the conveyor portion comprises a conveying trough made from two guide pieces which are mirror images of each other attached to a base plate and from two identical bent plates. The guide pieces engage in members in the bent plates and are clamped with them by clamping plates on the top side of the bent plates. The digging portion has a guide piece indentical with the guide piece of the conveyor portion. A basin-like plate of the digging portion is pivotably mounted by a welded substantially circular cross section strip on the breast wall side of the conveyor portion.

Abstract: A method in underground coal mining for separating the upper coal of the seam from the roof during the advancement of the upper sliding cap of a support frame, wherein the front edge of the cap is forced in a plane of the cap between the upper coal to be separated and the rock from which the coal is to be separated. During the advancement of the sliding cap, the sliding cap is alternatingly moved backwardly and forwardly, so that the from edge of the sliding cap separates the upper coal during its forward movement. Alternatively or additionally, when the front edge of the sliding cap contacts the upper coal, alternatingly higher and lower pressure can be admitted to the sliding cap in order to obtain a shaking effect. In this combined method, the sliding cap is advanced, the shaking procedure is carried out as the front edge contacts the upper coal, and the sliding cap is subsequently moved backwardly. The cycle is then repeated several times.

Abstract: An arrangement for supervising and controlling synchronous displacement of respective pistons of two cylinder-and-piston units, especially of an advancement and a roof cap displacement unit of a roof support assembly for use in underground mining, comprises first and second conduit systems each having two branches each connected with one of the piston and annular spaces of a different one of the units; a switching valve interposed between pressure and a return conduits and the first and second conduit systems; and first and second shut-off valves respectively interposed in those of the branches of the first and second conduit systems which lead to the piston spaces.

Abstract: A three-port, two-position electrohydraulic valve has an elongated valve member reciprocatably guided in a bore of the valve housing only by two sealing rings of small friction and including only two further sealing rings cooperating with sealing edges respectively provided on the valve member and the housing for controlling fluid flow between the three ports. The valve member is reciprocated between two end positions against the force of a return spring by an electromagnet. Such a valve requires only small forces for reciprocation of its elongated valve member, so that a small electromagnet is sufficient.The valve of the present invention favorably differs from known electrohydraulic three-port, two-position valves which are constructed as seat valves and operated in opening direction by an electromagnet of long stroke and which require also considerable forces during operation, due to large friction forces inherent with seat valves.

Abstract: An arrangement for controlled engagement of the tools of a coal planer, with a mine face comprises a scraper conveyor, provided on its front face directed toward the mine face with a guide rail guiding the coal planer for reciprocation along the mine face and a mechanism for tilting the conveyor and the coal planer about a substantially horizontal axis. The tilting mechanism is connected to the rear face of the conveyor and extends in its entirety rearwardly of the rear face of the latter. The tilting mechanism comprises a guide linkage pivotally connected at its front end to the rear face of the scraper conveyor while its rear end portion forms a housing for a fluid operated cylinder and piston unit, the piston rod of which is connected to a connecting rod guided by the guide linkage for movement in longitudinal direction and having an upwardly extending front section pivotally connected at its upper free end to the rear face of the scraper conveyor.

Abstract: A walking mine roof support has a roof engaging cap element, two supporting units each including a floor engaging plate member and a prop extending between a respective one of the plate members and the roof supporting cap element so as to support the latter, which floor engaging plate members are displaceable in a first direction toward a mine face and are spaced from one another in a second direction transverse to the first direction, and displacing elements for displacing the floor engaging plate members in the first direction and including two guiding elements spaced from one another in the second direction and two hydraulic cylinder-piston units operative independently of one another. Each of the hydraulic cylinder-piston units connects one of the guiding elements with a respective one of the floor engaging plate members so as to displace the latter relative to but independently of one another in the first direction.

Abstract: A mine roof support for an underground mine gallery comprises a sole plate adapted to rest on the floor of the mine gallery. The sole plate is connected by links to the region of the lower end of a rear shield, and the upper end of the latter is connected by pivot means to a roof shield, between opposite ends of the latter, in such a manner that a portion of the roof shield between the front end thereof and the pivoted means is considerably longer than the portion of the roof shield between the pivot means and the rear end of the roof shield. At least one extensible and collapsible prop extends between the sole plate and the portion of the roof shield which is located forwardly of the pivot means and at least one additional prop extends between the sole plate and the rear shield, so that the roof shield may be pressed against the roof of the mine gallery and be shifted relative to the mine face.

Abstract: In longwall mining wherein a mine roof is normally supported by a succession of arches each in turn supported at one mine wall on a respective leg, a plurality of vertically expensible holders are pressed up against a plurality of respective adjacent arches with a common first beam, and legs of the thus-supported arches are removed so that the mine wall can be worked at this location. For advancing along the longwall all of the holders except the holder at one end of the row of holders are pressed upwardly against the respective arches with a second beam. The leg of the arch of the end holder is replaced and then the first beam is dropped down away from the row of holders. The end holder is then displaced to the opposite end of the row and the first beam is advanced toward this other end and the end holder is positioned under the arch immediately adjacent the other end.

Abstract: In a longwall mining operation the roof of the breast extending laterally from a heading or gangway is supported by at least two pairs of pit props. Each pair is substantially identical, having an elongated upper part and an elongated lower part displaceable away from each other by hydraulic rams. In addition a shield is provided extending vertically between the upper and lower parts of each prop at the upstream end of the prop turned toward the stowage area. In addition the props furthest from the mine are substantially longer than the props closest to the mine and are provided at their ends turned toward the stowage area with side shields forming a closed chamber so as carefully to segregate the gob from the breast. The upper parts of the props are formed of several articulated sections so as to allow these upper parts to conform to the shape of the roof.

Abstract: A pit prop assembly has two pit props with parallel laterally spaced bases each having a front end turned toward a face conveyor and a rear end turned away from the face conveyor. A slide has its front end connected via positioning mechanism to the conveyor and its rear end connected via hydraulic ram to the bases. Each of the bases has at its rear end a side turned toward a confronting side on the slide and forming a side pair with this confronting side. One of these sides is formed with a formation that engages over and under another formation on the other side. One of these formations of each of the pairs of formations extends longitudinally toward the face so that the two formations can slide relative to each other. One of these formations may also be a pin whereas the other is a groove, or one may be a pair of facing convex surfaces flanking a straight edge.

Abstract: A pit prop assembly for use in a mine having a floor, a roof, and a face, comprises a pair of pit props having parallel elongated floor-engaging bases on each of which is pivoted a roof-engaging arm which may be pressed against the roof by means of a hydraulic ram extending vertically between each base and the respective arm. A pair of telescoping elements extend longitudinally between these two bases and one of the elements is pivoted at its front and rear end on respective front and rear end of one of the bases and the other element pivoted at its front and rear end on the respective front and rear end of the other base. A longitudinal-displacement ram is provided between these telescoping elements so that the two pit props can be displaced longitudinally relative to each other. In addition a transverse ram forms the connection between the rear of one of the elements and the corresponding rear of the corresponding base so that transverse displacement or swiveling of the two pit props is also possible.

Abstract: A mine roof support has at least two elongated support members laterally adjacent one another and extending transverse to the mine face. Each of the support members has an underside, a first end portion facing towards and a second end portion facing away from the mine face. A shield arrangement is mounted on the second end portions and extends upwardly thereof for supporting the mine roof. An extension arrangement is connectable to the first end portions of the support members with limited freedom of pivoting movement in vertical direction, and includes a ground plate extending to all of the support members and inclined relative to the undersides thereof, and terminal portions which rise upwardly towards the mine face in the region of the free ends of the first end portions of the support members.

Abstract: A base has one side facing towards and another side facing away from the face of the excavation. A shield has a first end portion and a second end portion, the latter being adjacent the other side and the shield extending upwardly and towards the one side. A roof-support cap is mounted on the first end portion. A mounting arrangement includes a shaft and mounts the second end portion of the shield on the base for pivoting about a pivot axis. A displacing arrangement serves to selectively displace the pivot axis in direction towards and away from the one side of the base, so as to maintain the cap in engagement with the roof despite different heights of the latter.

Abstract: An apparatus is disclosed for preventing cave-ins of mining galleries and other underground excavations. It includes a base, a roof-supporting shield extending upwardly from the base and a free edge to which a roof-supporting cap is pivoted, and an advancing arrangement for advancing the apparatus towards and away from a face of the excavation. The advancing arrangement has a shiftable carriage which can move towards and away from this face and which has an end directed towards the latter, and an extension section is telescopable into and out of this end and can be arrested in a plurality of different telescoped positions.