Abstract: A longwall mining shield base lift. The base lift includes a hydraulic cylinder having an apparatus for coupling the hydraulic cylinder to the longwall mining shield, a cylinder rod having a first end extending into the hydraulic cylinder and a second end for extending toward ground beneath the longwall mining shield, the second end being threaded axially, and a threaded wear pad threaded onto the cylinder rod. The wear pad includes a plurality of spanner holes for rotating the wear pad with a lever, at least one threaded retaining hole extending axially through the wear pad, and a retaining bolt threaded through the retaining hole until it contacts the cylinder rod.

Abstract: An equipment system for a self-retaining mining method mainly comprises a transition support, an end support, a following support, and a fast-retracting support. Working face gateroads do not need to advance in mining, and a coal mining machine may be used to cut a neat coal wall at the end of a district. The entry rib is automatically formed after roof caving, thus forming a gateroad in a re-mining process. The coal mining machine is under digital control when its end cuts the coal, automatically enabling the end to laterally cut the coal wall to form a vertical straight line, which is used as the entry rib of the gateroad. A scrapper conveyor works in coordination with an arc-shaped coal grabbing plate of the coal mining machine to clean up float coal at the end as much as possible.

Abstract: A float-swing hydraulic support, including a top beam, shield beam, elevating frame, base, adjusting jack, two float hydraulic columns, base raising unit, advancing unit, face guard unit, telescopic beam unit, hydraulic control valve block, and a valve block support. The columns are between the top beam and base, with upper ends ball-hinged to the top beam and lower ends ball-hinged to the base; the telescopic beam unit is in the front end of the top beam, and the face guard unit is hinged to the beam unit; the upper end of the shield beam is hinged to the top beam, the lower end is hinged to the upper end of the frame; the upper end of the jack is hinged to the shield beam, the lower end hinged to the base; the ends of the advancing unit are hinged to a scraper conveyor and the base, respectively.

Abstract: An apparatus applies mesh from a roll to a face of a mine passage. A spindle is adapted for supporting the roll of mesh. An arm supporting the spindle extends in a generally vertical direction and is adapted for rotation about an axis aligned with a direction of elongation of the mine passage such that the spindle traverses a path for applying the mesh from the roll to the face. A mast independent of the arm carries a drill head for drilling into the face of the mine passage. Related methods are also described.

Abstract: A shield canopy for a shield-type support for underground mining having a canopy plate and a supporting structure being welded on below the canopy plate and having a plurality of longitudinal spars which extend from a rear canopy region up to a front canopy region. At least two of the longitudinal spars having section struts which are provided with a top section flange and a web running perpendicularly to the top section flange, and the canopy plate and the section struts are angled upwards in the front canopy region.

Abstract: A gob shield for a shield support and a method for producing such a gob shield. The gob shield having a cover plate, two cap connecting joints for connecting the gob shield to a roof cap, and side plate pairs having respectively two side plates with bolt receptacles for the fastening of links of a link mechanism to the gob shield. In order to simplify the production of the gob shield, each cap connecting joint is a component part of a separately producible elongate assembly, which, by a rear end, can be welded in place in the interspace between the side plates of a side plate pair before this master assembly comprising assembly and side plate pair is welded to the cover plate.

Abstract: A shield cap for a shield-type support for underground mining includes a cap plate, with reception devices for the connection of hydraulic cylinder heads to the shield cap, and a supporting structure welded below the cap plate and having a plurality of longitudinal spars. At least two of the longitudinal spars include substantially I-profile struts having an upper profile chord, a lower profile chord and a middle chord running perpendicularly to the two profile chords. The distance between the upper and the lower profile chord decreases at least over a part length of each strut.

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: The disclosure concerns a mining roof support frame including at least one hydraulic lifting ram which is mounted on a bridging member connecting two base skids of the main frame, and which by way of a pressure-generated force can be extended downward against a walking bar of the walking unit of the mining roof support frame located between the base skids. In accordance with the disclosure, the base skids lifting device is connected with the bridging member such that it can pivot. With walking unit ram pivot pins withdrawn only on one side, the base skids lifting device can be pivoted out of the way about opposing pivot pins.

Abstract: An apparatus, system, and method are disclosed for supporting a gate entry or a connecting entry. The apparatus includes a support member, a controller, and a vehicle. The support member is configured to selectively engage a mine roof and a mine floor within a gate entry. The controller communicates with the support member to extend the support member to engage the mine roof and mine floor and retract the support member to disengage the mine roof and mine floor. The vehicle is connected to the support member and controller and moves the support member in response to a motive force. The support member, controller, and vehicle can operate and move independent of a mining face conveyor. The present invention is reusable, provides for mine roof and mine floor support as well as support of gate entry walls. The present invention has a minimal width profile to provide support while minimizing interference with the airflow within the gate entry.

Abstract: A prop head bearing between the roof bar and the prop (4) of a shield-type support frame, comprising a ball-joint socket (3) on the roof bar and open towards the prop for receiving a ball-joint head (2) on the prop (4), with at least one movable securing element (6, 7) which, when in a secured position, engages in a recess (12, 13) in the joint head (2) to prevent accidental lifting of the joint head (2) out of the socket (3), and with a bolt which locks the securing element (6, 7) in the secured position, in which that the securing element is in the form of a securing pin (6, 7) movable along its longitudinal axis between the secured position and an assembly position, wherein the securing pin (6, 7) is lockable by the bolt (14, 19) in the assembly position, in which it does not engage in the recess (12, 13) in the joint head (2).

Abstract: An improved lift boat includes a hull, a plurality of legs (preferably three), a plurality of pads, one pad attached to each leg, and a jacking mechanism for moving each upward and downward. Recesses in the hull receive the pads when the lift boat is underway. Preferably, the total bottom surface area of the pads is at least 30% of the surface area of the deck of the lift boat Preferably, the total bottom surface area of the pads is large enough such that, when the boat is loaded to capacity and is jacked up, the pads exert pressure of less than 7 p.s.i. on the sea floor. Preferably, the pads are partially recessed into the hull and extend laterally outward from the hull when the boat is underway to provide increased stability to the lift boat when it is underway.

Abstract: It is provide in a powered support frame, for large seam thicknesses with controlled gap sealing, that double acting gap cylinders (16, 27, 30) of several gap sealing elements (15) on a powered support frame are connected to a common pressure feed line (34, 37, 39) and to a common pressure return line (50) and are impacted with a uniform pressure when the gap sealing elements are to be extended.

Abstract: Shortwall mining equipment for extraction of some pillars in an underground coal mine has a series of self-advancing powered roof supports (1) for placement along the pillars (2) under extraction, the pillars under extraction being located within a panel (3) which is surrounded by barrier pillars (4), an armoured face conveyor (5) fixed to the barrier pillars, a light duty chain conveyor (18) and a belt conveyor (19). Each of the self-advancing powered roof supports (1) has at a goaf end a support mechanism (6) on a base frame (14) with a side shield (7) and hydraulic ram side arms (10). The base frame (14) is provided with front and back side hooks (11 & 12) to facilitate pulling of the support mechanism (6). The armoured face conveyor (5) is provided with a shearer (15) having a cutter drum (16) coupled with a centrally located ranging arm (17), an outbye end of he armoured face conveyor (5) being at a right angle to and set upon the light duty chain conveyor (18) as a freely advancing bridge.

Abstract: A shield support frame is constructed from main shoes (5) on the ground, hydraulic props (6) and a main canopy (7) borne by them and a gob shield (8) borne on guide links (10). On the face side, there is a front cantilever (24) linked so as to be adjustable in height from the main canopy (7), on which a sliding canopy (25) is guided so as to be able to slide in the direction of the face. On the ground, an adjustable baseplate (21) is arranged at a distance in front of the main shoes (5) and connected via a horizontal joint axle (22) to the extending part of the shifting gear (3). Front assembly props (23) mounted on the adjustable baseplate (21) support the sliding canopy (25). The tip of the plate of the adjustable baseplate (21) is lifted from the ground during forward movement.

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: A mine roof support frame has a pair of spaced-apart floor skids on which hydraulic props support a roof engaging structure. A shifting mechanism with a ram in a trough-like housing and a guide beam is positioned between the skids and serves to displace the frame relative to a scraper-chain conveyor and vice versa. The guide beam is a flat plate with a width more or less the same as the space between the skids and rests directly on the floor. The piston rod of the ram is coupled to the guide beam near the conveyor, the ram cylinder is coupled to the housing and the housing is coupled to the skids at the stowage end. The ram housing has a guide rail on the underside which mates with a guide element on the top of the guide beam. Levers pivotably coupled to the floor sills in front of the ram housing are operated by piston and cylinder units to engage on the guide beam to lift the floor skids partially during advancement of the frame.

Abstract: A grid composite for protecting men and longwall mining equipment during longwall shield recovery includes a regular polymer geogrid structure formed by biaxially drawing a continuous sheet of select polypropylene material which is heat bonded to a polyester fabric. The grid composite is secured over caving shields of longwall mining equipment during a longwall mining operation.

Abstract: A walking mining prop has a skid-lifting assembly in the region of the ram which braces the roof cap with respect to the skid formed by a bridge from which lifting cylinders are articulated and suspended. The pistons of these lifting cylinders are articulated to a pressure plate which at least partly surrounds the guide rods of a guide-rod assembly on which the skid is guided, a mechanism being provided to advance the skid relative to the guide-rod assembly.

Abstract: The mobile stope support apparatus comprises a number of individual units (10) which are interconnected by hydraulic cylinders (12). Each of the units (10) has a series of upright, double-acting legs (20). The legs (20) have independent bases of rounded shape and they are pivoted to an overhead canopy (22) which can be raised and lowered by appropriate actuation of the legs. Each unit also has a fore-and-aft hydraulic cylinder (34) which is connected to a common rail (37), the cylinder (34) being pivotable, by the action of a cylinder (36) in an upright plane to raise and lower the rail. By appropriate sequential operation of the various cylinders, the units can be advanced in turn to advance the whole apparatus. In addition, by appropriate operation of the cylinder (36), the front legs (20) can be lifted off the footwall to facilitate movement of the unit over a rough or uneven footwall.

Abstract: A mine roof support or lining frame for use in mine workings with thick inclined seams has hydraulic props mounted between an inclined goaf shield and a floor sill. The floor sill is coupled with a shifting mechanism to a frame supporting a conveyor extending along a working face of the seam. Mineral from a region of the seam extending over the support passes through an opening in the shield onto a chute which takes an inclined disposition parallel to the conveyor. Material transferred to the chute discharges in the direction of transport of the conveyor.

Abstract: A mine roof support assembly comprises a mine roof support having a first end adjacent to the mine face and a second end remote from the mine face, an advancing mechanism for advancing the roof support towards the mine face, and a base lifting mechanism. The base lifting mechanism includes two substantially parallel arm members pivotally connected to a base section of the mine roof support, and two lifting rams each of which acts between a respective arm member and the roof support. The lifting rams act on the roof support at a position which is nearer than the center of gravity of the roof support assembly to the second end of the roof support to pivot the roof support relative to a respective arm member and thereby lift the first end of the roof support clear of the ground. Also, an advancing ram of the advancing mechanism is connected to the arm members by an arrangement which provides some movement of the ram relative to the arm members in two mutually transverse directions.

Abstract: This invention relates to a lemniscate mining support comprising a foot piece, a roof bar, an anti-fall shield connected between the foot piece and the roof bar, and movable props between the roof bar and the foot piece so as to move the roof bar. The joints connecting the anti-fall shield to the foot piece and the anti-fall shield to the roof bar are positioned so that the anti-fall shield can be positioned at a steep angle, relative to the roof bar so that damage to the anti-fall shield can be minimized while allowing the anti-fall shield to contribute to the support of the roof bar.

Abstract: A roof support employs an hydraulic piston and cylinder unit as an adjustment device between the goaf shield and the roof-engaging structure. The cylinder unit is mounted to the shield with the aid of a bearing body defining a cup receiving a spherical end of the cylinder. The body also has recesses accessible via offset openings in which journals projecting from the cylinder are located. Locking pieces detachably fitted to the shield block the openings to retain the journals therein yet permit easy assembly and dismantling of the unit.

Abstract: To increase the height of operation of a shield type roof support an attachment is fitted to the floor sill or to each of a pair of spaced-apart floor skids. The attachment has side walls with bores for receiving pivot pins used to link the attachment to the floor sill or skid and to guide levers connected to the goaf shield. A transverse body extends between the side walls and defines a socket for forming part of a ball-and-socket joint connecting the attachment to a hydraulic prop. The side walls of the attachment have under surfaces which rest on a support surface of the skid or sill near the working face.

Abstract: The movable consolidating trestle (2) has driven caterpillars (1). The consolidating trestle comprises a cap (3) being supported on the frame (11) via props (5). The cap (3) has at least one front-side section which is bent, rounded or bendable in direction to the frame. A bent section (8) includes with the plane of the cap (3) an angle (.alpha.) which is greater than the maximum angle (.beta.) of inclination with which the cap can be obliquely adjusted relative to the frame (11). When giving the cap (3) an inclined position, there results a horizontal component of the load-exerting force (14), said horizontal component facilitating saving of the consolidating trestle.

Abstract: A mine roof support has a roof engaging canopy 23, a floor engaging base 12, and a hydraulic jack 24 acting between the canopy and the base for urging the canopy and the base apart. The hydraulic jack 24 is provided with at least two different locations, movement of the jack means 24 from one location to another location bringing about an alteration in the distance between the canopy and the base. The invention makes it possible to provide a hydraulic jack having a first working position in which the hydraulic jack is arranged in the optimum position to support a mine roof, and a second stowing position for transportation purposes.

Abstract: A self-advancing mine roof support comprising a floor engaging base 11, a roof engaging canopy 12, hydraulic jacks 19a, 19b to urge the base and canopy apart, and a linkage system located towards the rear of the support. The linkage system comprises an inclined shield member 22 pivotally connected to the canopy 12, and at least two links 23, 24 interconnecting the shield and the base. The jacks 19a, 19b, are located substantially halfway along the length of the base and extend substantially vertically from the base. There is a hydraulic jack 18 operable between the roof engaging canopy 12 and the linkage system to effectively counterbalance the projection on the canopy 12 which extends forwardly of the jacks 19a, 19b.

Abstract: A roof engaging structure for a mine roof support comprises at least two relatively movable roof engaging members 21 and 23, which are coupled together by at least two spaced-apart pivotal joints 25 and 26. The pivotal joints combine to influence the relationship of the roof engaging surfaces of the two members. In one embodiment for example, the roof engaging surfaces of the two roof engaging members may adopt either an angular or a parallel relationship with respect to one another, one surface lying at least partially below the adjacent surface. The arrangement enables the roof engaging structure to shape itself to various forms of mine roof, while preventing jack knifing of the forward end of the roof engaging structure.

Abstract: The invention refers to a movable trestle of approximately rectangular horizontal projection and serving the purpose of supporting the roof in underground cavities in particular serving the purpose of securing the excavation edge when recovering pillars in coal mining, comprising a cap (2) supported against a base frame (1) by hydraulically extensible props extending approximately in vertical direction to stratification. The lower portion of the trestle is, preferably at all sides, covered by a stationary shielding means against the ingress of rubble into its interior and horizontal protective plates (3) overlapping one another in a scale-like manner and being guided on sliding plates (8) for relative shifting movement in height direction are provided within the area of the expandable portion of the trestle. The protective plates (3) are arranged on the rear side (12) of the trestle and on the both sides (10, 11) adjoining the rear side of the trestle.

Abstract: A mine roof support includes a pair of substantially-parallel floor-engaging members, a roof engageable member, a shield pivotally-connected to the floor-engaging members, by at least one pair of parallel links, and pivotally-connected to the roof-engageable member, and prop means carried by the floor-engaging members by which the roof-engageable member can be urged into engagement with a mine roof. A strengthening member connects the pair of parallel links. The strengthening member and the pair of parallel links provide the sole connection between the rear-end portions of the floor-engaging members by which the forces tending to cause relative displacement of those rear-end portions in the vertical direction are substantially resisted.

Abstract: A mine roof support has gap seals in the form of L-shaped plates on its roof cap and goaf shield. The side walls of the plates overlap at the junctures between the roof cap and the goaf shield and these walls are interconnected with pivot connections each of which is composed of complementary components fitted into openings in the walls. The components combine to form a pivot journal and and are locked to one another by a twist catch which can be released by relative rotation of the components.

Abstract: A mine roof support has gap seals in the form of L-shaped plates on its roof cap and goaf shield. The side walls of the plates overlap at the junctures between the roof cap and goaf shield and are connected with pivot connections each of which is composed of a pin inserted into apertures in the side walls of the plates. The pin has a peripheral groove at its inner end region which receives an arcuate yoke plate serving as a support. The yoke plate is itself detachably secured in place with a releasable rod permitting the pivot connection to be easily dismantled.

Abstract: A device designed to skid the chock blocks of a powered support of the type used in coal mines. The front of the skid cylinder is connected with a skid bar whose front end is jointed on an armored conveyor. The rear end of the cylinder is jointed on the rear end of an arm whose front end is jointed on the chock block pads.

Abstract: The invention relates to a travelling support pillar for use in underground mines.The support pillar has a link subjected to the action of a positioning jack. The positioning jack extends between a gate and the rear of the top of the pillar. The positioning jack hydraulically locks the support pillar by means of a sliding pressure-relief valve to compensate for load changes due to the movement of the floor or the roof. The link also permits the support pillar to be collapsed for transportation, and it provides a support pillar with a shorter length and a lower height in the collapsed position, and it permits the top of the support pillar to be placed closer to the working face of the mine when the pillar is in its roof supporting extended position.

Abstract: A shield support, suitable for use in mines, comprising a floor-engaging structure, a roof-engageable canopy, extendible and contractible prop means disposed between the floor-engaging structure and the canopy, and a shield assembly pivotally-connected to the canopy at or near its rearward end portion. The shield assembly includes a lazy tongs linkage, one element of which is pivotally-connected directly to the floor-engaging structure and another element of which is pivotally-connected to the floor-engaging structure through the intermediary of a further element.

Abstract: A shield support, suitable for use in mines, comprising a floor-engaging structure which includes two sledge or like elements disposed side-by-side and spaced apart one from the other, a roof-engageable canopy, a shield mounted for pivotal movement with respect to the canopy and extendable and contractible prop means, carried by said elements, which are operable to adjust the height of the canopy. A pivotal guide linkage for supporting the shield from said elements includes links which are so connected to those elements and to the shield that the elements are rigidly coupled together only through the intermediary of those links and the shield.

Abstract: A shield-type support frame for serving as a face support in underground mining operations having a bottom structure, a one-piece roof cap, at least one hydraulic plunger connecting the bottom structure and the roof cap and two shield elements arranged side by side, which can be adjusted in height separately and which are each pivotally connected to the bottom structure and the roof cap. Joint connections between each shield element and the roof cap permit tilting of the roof cap relative to the shield elements about axes extending in the forward direction.

Abstract: A mine roof support unit has a roof shield for supporting the roof of a mine working, and a goaf shield for screening off the goaf space of the working. The mine roof support unit is provided with dust suppression means constituted by a flat-section spray nozzle arranged along the front edge of the roof shield, or along the top edge of the goaf shield. The spray nozzle is directed upwardly away from the roof support unit and towards the goaf space.

Abstract: A mine excavator especially for heavy coal beds comprises a base on which the power loader and conveyor are provided and on which the roof support or shield is pivotally mounted. According to the invention, a back member connected to the roof plate and spaced above the base has a downwardly and forwardly swingable door which deposits caved material onto the conveyor at a forward portion of the main base.

Abstract: A roof support for coal-mining apparatus or other tunnel-excavating equipment has a shield plate with several rearwardly diverging and deepening longitudinal grooves in its upper surface. The grooves are designed to carry off detritus as the support advances and are spaced closely enough to form ribs therebetween adapted to crush larger chunks of overburden landing thereon.

Abstract: A mine roof support has a goaf shield with a lemniscate guide system linking the shield to floor-engaging skids. A walking-mechanism is disposed in a channel between the floor skids. In order to prevent rubble or goaf material from penetrating into the channel the guides of the lemniscate system have connections which are spaced one above the other and to which one or several screen plates can be removably and replaceably attached with the aid of push-in locking-bars. The screen plates also advantageously serve to keep the floor skids apart by a minimum distance to prevent jamming of the walking mechanism.

Abstract: The invention relates to a structural frame for mining operations wherein at least one stabilization element is provided and coupled between the roof of the seam cap and the floor of the seam support base which is pivotable around a pivot axis extending in the longitudinal direction of the truss. In order to prevent damage to the stabilization element or the pivot axis during occuring mountain forces, the stabilization element and/or the guides or links guiding the same are designed as yielding spring elements yieldable against compression and tension forces whose restoring forces are dimensioned so large that the parts which have been released from the bracing between the roof of the seam and the floor of the seam can be adjusted back into the initial position by the effect of the restoring forces.

Abstract: The support assembly is made up of a floor-standing runner member 1, a hydraulically vertically-adjustable prop 2 mounted on the same, a roof canopy 3 supported by the same and a rockfall shield 4 hinged to the same on the backfill side which is guided to be pivotable in a vertical plane by two direction-control members 5 and 6 articulated to the runner member so as to be spaced apart one behind the other. The front direction-control member 6 is constructed as a hydraulic thrust piston mechanism. Via a control circuit 8 the hydraulic control valve 7 of the direction-control member 6 is connected to measuring devices 9 usable to measure the position of at least two mutually variably spaced apart support assembly reference points. If the reference points deviate from the preset normal position of the support assembly, pressure fluid acts on the front direction-control member 6 via the control circuit 8 until the normal position has been regained.

Abstract: A mine roof support unit has a roof bar supported on a floor sill by hydraulic props. The floor sill is constituted by a face-side floor sill part and a goaf-side floor sill part. The two floor sill parts are telescopically interconnected. Each of the floor sill parts supports a pair of hydraulic props. Hydraulic rams are provided for moving each of floor sill parts relative to the other floor sill part in the direction of roof support unit advance.

Abstract: In combination with a mine roof support including a sole plate resting on the sole of a mine gallery, a roof shield engaging the roof of the mine gallery, and fluid-operated extensible and collapsible props extending between the sole plate and the roof shield for pressing the latter against the roof, a method for controlling the force at which the roof shield is pressed against the roof of the mine gallery comprising the steps of providing an overpressure valve communicating with the interior of each prop and adjusting the opening pressure of the valve in dependence on the inclination of the props with respect to the sole plate; and an arrangement for carrying out the method.

Abstract: A mine roof support has hydraulic props mounted between a floor sill and a roof bar which can be raised and lowered by extension and retraction of the props. A goaf shield is pivotably connected to the rear of the roof bar and is linked via levers to the floor sill. A hydraulic piston and cylinder unit is connected between the roof bar and the goaf shield. Apparatus serves to prevent damage to the support components, and especially to the unit which could be extended beyond its full stroke when the props are retracted to bring the goaf shield and the roof bar more or less into alignment. The protective apparatus is composed of a compact valve device operated by a member, such as a cam, to block the props from hydraulic pressure when the goaf shield and the roof bar assume a pre-determined angular disposition. Both the valve device and its operating member are disposed in a protected position within chambers formed inside the roof bar and the goaf shield adjacent the pivot connection therebetween.

Abstract: A mineral mining installation serves to win mineral by explosive blasting. The installation employs a shuttle conveyor arranged alongside a mineral face. Roof supports stand side-by-side at the side of the conveyor remote from the conveyor. The roof supports are connected to the conveyor through shifting rams and have roof-engageable caps or the like supported on hydraulic props. The pans of the conveyor have upstanding walls at the rear side nearest the roof supports which carry rails at their upper ends. The roof caps have wall components pivoted thereto and hydraulic piston and cylinder units serve to swing the wall components up and down. When explosive blasting takes place the wall components are swung down to engage on the walls of the conveyor pans to form a screen between the winning region and the access region of the working.

Abstract: A slidable filling dam has along the heading dam segments (4) articulated in a hinged roof-bar (7) of a mine lining. The slidable dam has near-floor beams (1) which are provided at their ends with terminal eyes (2) to connect two neighboring dam segments (4) at the point of their connection with footings (9) by means of bolts (10, 11). The near-floor beam (1) has in its central part at least one central eye (5) to fix a hydraulic ram (6) pulling up segments (4) of the filling dam.

Abstract: A mine excavator especially for heavy coal beds comprises a base on which the power loader and conveyor are provided and on which the roof support or shield is pivotally mounted. According to the invention, a back member connected to the roof plate and spaced above the base has a downwardly and forwardly swingable door which deposits caved material onto the conveyor at a forward portion of the main base.