This application claims priority to German Patent Application No. 10 2005 040 272.0 filed on Aug. 24, 2005.
The invention relates to a method for pillar recovery in the extraction of minerals and raw materials in underground stratified beds in chamber-and-pillar working, with a retreat section which extends over a plurality of pillars separated from each other by transverse pillar galleries running transversely and by longitudinal pillar galleries running longitudinally, and whose work face is worked between two outer transverse pillar galleries with an extraction device that has a rotary-cutting or cutting operation in long face working or short face working. The invention also relates to a tubbing unit for pillar recovery in the chamber-and-pillar working of minerals and raw materials in underground stratified beds, which unit can be arranged in a pillar gallery between two pillars, can be displaced to a different position and has a means of support that is vertically adjustable by means of props and can be pressed against the roof for the purpose of supporting the roof.
In the underground extraction of stratified minerals and raw materials, such as coal and salt in particular, longwall working on the one hand and chamber-and-pillar working on the other are used as traditional extraction methods. Unlike longwall working, the roof is supported in chamber-and-pillar working by the natural standing pillars for keeping open the cavities created by and required for mining, and further support is provided by anchor propping in the worked chambers and driven up pillar galleries. Because of the natural pillars left standing by the system there are necessarily considerable working losses, depending on the required pillar dimensioning. These working losses may amount to as much as 60% of the workable total deposits of minerals or raw materials. On the other hand, chamber-and-pillar working is characterized by high production efficiency at relatively low investment costs, very high operative flexibility and the low degree of organization required, a particular advantage of chamber-and-pillar working being the relatively simple control of the rock mechanics. In chamber-and-pillar working bed-specific factors, such as total deposits, extension and distribution of deposits and frequency of disturbance of the beds are far less significant than in long face or short face longwall working. In chamber-and-pillar working a method is also known for consistently improving the total degree of utilization by recovering the raw materials and minerals contained in the pillars by working the pillars in a second extraction stage, so-called pillar recovery or re-pillaring, and the invention relates to this area of chamber-and-pillar working.
A generic method for pillar recovery is disclosed in DE 30 09 923 A1. In the known method, the retreat section in long face working is extracted with a work face running in an arc shape, using rotary-cutting or cutting extraction devices in which the extraction device, running in a curved shape, as is normal in long face working, is supported and pushed with hydraulic shield supports. However, since a relatively high curvature of the conveyor of the long face extraction device on which the extraction machine is guided is required, the industrial use of this method presents problems. Working or driving through the open pillar galleries, with roof control, could also cause serious problems, with the result that a sufficiently high production output could not be achieved with the known method.
DE 32 38 256 A1 discloses, by way of example, tubbing units for pillar recovery consisting of a plurality of hydraulic tubbing frames connected together, which frames are driven and moved by chain or caterpillar tracks. The known tubbing units have a cover that can be pressed against the roof, each cover extending over the width of one of the tubbing frames.
The object of the invention is to provide a method for pillar recovery and tubbing units for this purpose with which a high production output can be achieved in pillar recovery at the lowest possible technical expenditure for the available equipment, using short face or long face extraction devices known from longwall working.
This and other objects are achieved, in their aspect according to the method of the invention, in that the extraction device is aligned obliquely to the longitudinal pillar galleries, whereby the retreat face leads the entire remaining retreat at face one of the outer transverse pillar galleries, and in that the roof is supported in the working direction, in front of the retreat face and in front of the extraction device, by a plurality of displaceable tubbing units arranged between the pillars in the pillar galleries. The solution according to the invention is based on an oblique alignment of the extraction device engaged in long face working or short face working, which device is supported by a preferably systematic support of the open pillar gallery system of the longitudinal pillar galleries and transverse pillar galleries in front of the work face. Here the retreat face extends over approximately two to four pillars, depending on the dimensioning (length and width) of the pillars. According to the invention the work face therefore always extends only over a partial area of the extent of all the underground pillar galleries in the bed. The pushing of an extraction device running obliquely to the longitudinal pillar galleries can be controlled much more easily than the pushing of an extraction device arranged in a curved shape.
In the method according to the invention at least two tubbing units per pillar are preferably arranged in the longitudinal pillar galleries and at least one tubbing unit per pillar is preferably arranged in each inner transverse pillar gallery, which are reversed should system conditions require this. It is particularly advantageous if three to five tubbing units per pillar are arranged in the longitudinal pillar galleries and one tubbing unit is arranged in each inner transverse pillar gallery. Preference is given to the use of semi-mobile tubbing units which do not have their own drives but which are displaced by means of a vehicle which has, for example, a loading platform, a lifting device, a grab or the like for temporarily receiving, conveying and depositing the tubbing units. Tubbing units, preferably with relatively little engineering, are therefore used to support the roof in the direction of working, in front of the retreat face. To allow displacement in the method according to the invention it is particularly advantageous for the tubbing units to be retractable both in height and width. It is particularly advantageous for the tubbing units to be designed so that the retracted tubbing units can be moved through extended and set tubbing units, i.e. tubbing units supporting the roof, with the vehicles during displacement. This has the added advantage that accidental loosening of the roof strata due to frequent loading and unloading of tubbing units is avoided, since it is not necessary to rob and displace a tubbing unit that is already set in the pillar gallery in order to set another tubbing unit in essentially the same place later. Instead a tubbing unit, once set, can remain in its setting position until it has to be displaced in any case, for working the next pillar, due to the progress of the work.
To achieve the above-mentioned object the invention proposes tubbing units in which the means of support has two support beams that are arranged at a certain distance from each other and can be moved relative to each other and are independent of each other to a limited degree, each of which beams is supported by means of two props and a steering gear arranged between the props on a floor runner. Here a transfer frame is arranged between the support beams, to which frame at least one of the support beams is movably secured for remote adjustment of the support beams by means of intermediate guides, and the tubbing unit can be conveyed with a vehicle so that tubbing units that are not set can be moved with the vehicle. During conveyance the tubbing unit can preferably be supported by the transfer frame on the vehicle or gripped by it. Due to the remote adjustment of the support beams it is possible that during the displacement of a tubbing unit other tubbing units supporting the roof can remain set. The remote adjustment of the support beams should be sufficient for a tubbing unit, when folded or contracted, i.e. when the tubbing unit is reduced in height and width, to be conveyed with the vehicle between the floor runners of a set tubbing unit and the tubbing unit expanded to its full width.
In an embodiment of the invention the support beam can be moved by means of telescopic intermediate guides, constructed as adjusting cylinders, in a linear movement. In an alternative embodiment the intermediate guides can be swiveled on the transfer frame and the support beam. In this embodiment it is particularly advantageous for a hydraulically adjustable adjusting cylinder to be arranged between one of the intermediate guides and the transfer frame in order to be able to effect the inward folding or collapse and unfolding of the support beams and floor runners of the tubbing units by simple hydraulic means. It is particularly appropriate if the intermediate guides can be swiveled by means of the adjusting cylinder between a first swivel position, in which the adjusting cylinder and the support beam lie parallel with the longitudinal side of the transfer frame, and a second swivel position in which the support beam is laterally extended and the intermediate guide stands at an angle to the longitudinal side of the transfer frame. In certain applications it may be sufficient for only one of the two support beams to be movable or swiveled. In the preferred embodiment, however, both support beams can be moved and swiveled by intermediate guides on the transfer frame.
A particularly simple design of the tubbing units may be obtained when the props and/or the adjusting cylinders can be connected to longwall hydraulics of a long face or short face extraction device used in pillar recovery and/or to the hydraulics of a hydraulic unit mounted on the vehicle. In this embodiment the tubbing units are therefore passively adjustable and do not have their own drive or their own hydraulic unit, but must be connected either to the longwall hydraulics or to a hydraulic unit mounted on the vehicle to enable the tubbing units to be set and the adjusting cylinders to be extended and/or contracted. Also in preference, the connection joints of the intermediate guides on the support beam side are arranged on plummer blocks which are secured tiltably to the associated support beam for variable vertical adjustment of the two support beams. In this embodiment the two support beams can be extended to different heights. The steering gears guiding the movement of the support beams are suitably designed as lemniscate gears and/or the swiveled intermediate guides are designed as parallel steering gears. The lemniscate gear ensures that the support beams can only be extended parallel with the associated floor runner against which the props abut, and the parallel steering gear ensures that the support beams can be swiveled in parallel and uniformly on the transfer frame between both support beams, which frame is not normally loaded with the roof load during operation. Here it is particularly advantageous for the upper side of the support beams to be higher than the upper side of the transfer frame.
The underside of the transfer frame may have a guide or support for the loading platform of the vehicle to enable the tubbing unit to be deposited on the loading platform of a vehicle by sliding the transfer frame underneath it, thus achieving optimum depositing of the tubbing units on the loading platform of the vehicle with which the tubbing units are then moved. Alternatively the transfer frame of the tubbing unit may also be provided with engaging means or engaging pockets or the like for a lifting device or grab device carried on the vehicle.
Further advantages and embodiments of the invention are detailed in the following diagrammatic description of exemplary embodiments according to the invention shown in the drawing, where:
In
Pillars 2 are recovered in the exemplary embodiment shown in the advancing or retreat face in short face working in working direction A with an extraction device generally denoted by reference number 5, which device, in a manner intrinsically known in longwall working, comprises a multiplicity of electrohydraulic tubbing frames 6 arranged adjacent to each other, by means of which frames the working longwall is kept open on the work face, and a conveyor trough 7, on which is guided, for example, a drum-cutter loader 8 traveling backwards and forwards between both ends of the short face extraction device 5, is pushed in working direction A. Extraction device 5 extends over a retreat face of three pillars 2, in the exemplary embodiment shown, and the changes of direction for conveyor 7, with the drive devices not shown, are each arranged in an outer transverse pillar gallery 4. In the case of a retreat face extending over three pillars 2, two further, inner transverse pillar galleries 4 lie between the two outer transverse pillar galleries 4. As is known per se, the material extracted on the retreat face on pillars 2 is transferred by longwall conveyor 7 to a drift conveyor 9, which is laid in one of the two outer transverse pillar galleries 4. The direction of conveyance is denoted by reference letter F. To the side of both outer transverse pillar galleries 4 there are further pillars 2, with pillar galleries 3, 4, which will be worked at a later stage, and the roof falls in behind the extraction device as thrust 63.
According to the invention, extraction device 5 is arranged at an angle α, preferably of approx. 10°, obliquely to the alignment of longitudinal pillar galleries 3, whereby the retreat face is in advance of the remaining retreat face on pillars 2 in the right outer transverse pillar gallery 4 shown in
In
The structure of tubbing units 10 and the displacement of tubbing units 10 by means of vehicle 50 are now explained with reference to
As shown in particular in
The width of tubbing units 10, as illustrated particularly clearly in
Vehicle 50, shown in
In the preferred exemplary embodiment shown, tubbing units 10 form passive frames which must be connected for actuating props 13 or adjusting cylinders 30 either to the longwall hydraulics of the extraction device (5,
For the person skilled in the art numerous modifications are evident from the previous description, modifications that will fall under the protection of the dependent claims. In the method according to the invention four or more pillars could also be worked in long face longwall working, or only two pillars could be worked simultaneously. In the case of the tubbing units only one of the support beams could be swiveled to the transfer frame. The number of tubbing units used may be varied according to the application and the ratio of pillar size to pillar gallery width. The transfer frame may consist of a solid plate or a lined longwall structure. The extraction device may also comprise a coal plane. If they still lie adjacent to pillars to be worked, the outer transverse pillar galleries are kept open by suitable measures. The adjusting movement of the tubbing units may also take place by other means. The vehicle may also have a grab, a crane or other lifting device for receiving the tubbing unit for conveying to another site with the vehicle.
Number | Date | Country | Kind |
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10 2005 040 272 | Aug 2005 | DE | national |
Number | Name | Date | Kind |
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3328966 | Creuels et al. | Jul 1967 | A |
3505823 | Bell | Apr 1970 | A |
3855802 | Alacchi | Dec 1974 | A |
3892100 | Jamison | Jul 1975 | A |
4026118 | McCay, Jr. | May 1977 | A |
4143991 | Stafford | Mar 1979 | A |
5584611 | Clonch | Dec 1996 | A |
Number | Date | Country |
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30 09 923 | Mar 1980 | DE |
32 38 256 | Oct 1982 | DE |
Number | Date | Country | |
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20070046094 A1 | Mar 2007 | US |