CA1129661A - Underground mining roof support systems and supports for use with such systems - Google Patents
Underground mining roof support systems and supports for use with such systemsInfo
- Publication number
- CA1129661A CA1129661A CA360,230A CA360230A CA1129661A CA 1129661 A CA1129661 A CA 1129661A CA 360230 A CA360230 A CA 360230A CA 1129661 A CA1129661 A CA 1129661A
- Authority
- CA
- Canada
- Prior art keywords
- roof
- legs
- relatively
- support
- supports
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005065 mining Methods 0.000 title description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 6
- 239000011707 mineral Substances 0.000 claims description 6
- 238000005520 cutting process Methods 0.000 description 8
- 239000011435 rock Substances 0.000 description 6
- 230000004913 activation Effects 0.000 description 4
- 238000009412 basement excavation Methods 0.000 description 4
- 238000009434 installation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000012856 packing Methods 0.000 description 4
- 238000011010 flushing procedure Methods 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 230000001934 delay Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
- E21D23/0004—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor along the working face
- E21D23/0017—Pile type supports
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
- E21D23/0086—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor in galleries
- E21D23/0091—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor in galleries at the junction with the working face
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Excavating Of Shafts Or Tunnels (AREA)
Abstract
ABSTRACT OF THE INVENTION
UNDERGROUND MINE ROOF SUPPORT SYSTEM AND SUPPORTS FOR USE IN SUCH
A SYSTEM
An underground mine roof support system comprises a plurality of roof supports arranged in side-by-side relationship along a longwall face, at least two adjacent supports comprising a set of relatively forwardly located legs and a relatively rearwardly located single leg such that, in use, an access passage is defined between the two single legs of said two adjacent roof supports.
UNDERGROUND MINE ROOF SUPPORT SYSTEM AND SUPPORTS FOR USE IN SUCH
A SYSTEM
An underground mine roof support system comprises a plurality of roof supports arranged in side-by-side relationship along a longwall face, at least two adjacent supports comprising a set of relatively forwardly located legs and a relatively rearwardly located single leg such that, in use, an access passage is defined between the two single legs of said two adjacent roof supports.
Description
96~
MINE ROOF SUPPORT SYSTEMS AND MINE ROOF SUPPORTS FOR USE IN SUCH
SYSTEMS
his invention relates to underground mine roof support systems and to mine roof supports for use with such system In particular, although not exclusively, the present invention relates to underground mine roof support systems for use on longwall faces in regions adjacent to the junctions of the longwall faces with services roadways where it frequently is necessary for mine operators to gain aocess to the longwall face from the service roadway and/or from equipment installed in pack areas adjacent to ; the services roadway, for example, packing equipment arranged to ~; .
build packs of rock debris generated during the extension of the roadway, the packs tending to provide a buttress for settling strata in the vicinity of the roadway.
Typically, previously known mine roof support systems associated with a junction between an advancing longwall face and : 15 a service roadway, included a plurality~ of roof support units arranged in side by side relationship along the length o~ the longwall face and each comprising a rearwardly extending base unit constituted by a pair of laterally spaced floor mounted skids, a rearwardly extending roof canopy unit provided with forwardly and rearwardly extensible roof beams or bars for supporting or containing :, the mine roof in the vicinity of a ripping lip which is constituted by the area of mine roof immediately in advance of the roadway and which is excavated to extend or advance the roadway, and also in the vicinity of the mine roof associated with the previously mentioned pack areas.
Each roof canopy unit is supported from its associated base unit by means of four or more hydraulically extensible legs or jacks arranged as a pair of rela-tively forwardly located, laterally spaced legs and as a pair of relatively rearwardly located, laterally spaced legs. Each pair of legs is mounted in a mounting unit bridging the two previously men-tioned floor mounted skids of the base unit such that, in use, when theplurality of roof supports are installed in side-by-side relationship along the length of longwall face a PaSsage or walkway for mine operators is defined between the two rowsof forwardly and rearwardly located legs.
` If a support comprises more than two pa:irs of legs, the further legs are arranged as a pair of laterally spaced :Legs mounted relatively rearwardly of the previously mentioned relatively rearwardly legs. Both PairS of relatively rearwardly legs may be mounted in a common mounting unit bridging the floor mounted skids of the base unit. Each of the hydraulic-; ally extensible legs on each support unit has the same preset, preselected loading capacity whereby each leg applied the same loading reaction tothe roof canopy unit and is set to yield when the load tends to increase above the preselected loading capacity.
With such a prior known mine roof support system the mounting units for the relatively rearwardly located pairs of legs tend to prohi~it or hinder the passage of mine operators between legs in each : . ~
29~6~
pair. Moreover, in order to adequately support the mine roof along the longwall face it is necessary to have each roof support installed closely adjacent to its neighbours so that adjacent rearwardly located legs on two adjacent supports tend to be so close to one another that the mine operator is prohibited from safely passing between two adjacent installed supports. Thus, a disadvantage of such prior known mine roof support systems is that access for mine operators to the aforementioned passage or walkway from the service roadway or from equipment is difficult, especially if bulky equipment or apparatus is to be brought into the region of the passage or walkway. Such bulky equipment or apparatus, for example, may comprise heavy conveyor equipment or a loaded stretcher.
It is an object of the present invention to provide a mine roof support system which tends to overcome or reduce the above mentioned disadvantage and which tends to provide relatively easier and safer access to the passage or walkway defined by the roo supports and extending generally along the longwall face.
The present invention provides an underground mine roof support system for a longwall face having a winning machine traversable to and fro along a path adjacent to the working face, and having at least one service roadway for the longwall face, the system being associated with a portion of the longwall face adja-cent to the junction of the longwall face with said service road-way, the system comprising a plurality of advanceable roof supports which, in use, are arranged in a side-by-side relationship and which, in use, are advanced in sequence towards the newly exposed working face as mineral is extracted by the winning machine, each ~Z~6~
support having a base unit, a roof canopy unit provided with a rearwardly extendable beam capable of being extended from the rear of the roof canopy towards the service roadway, and a plurality of hydraulically extensible legs extending between the base and roof canopy units, which units, in use, extend rearwardly from adjacent to the working face, at least two adjacent roof supports comprising a set of relatively forwardly located legs and a relatively rear-wardly located single leg such that, in use, an access passageway is defined between the two relatively rearwardly single legs and the base and roof canopy units of said two adjacent roof supports, the passageway temporarily being extendable towards the service roadway upon advance of the associated supports by the rearwardly extendable beams.
Advantageously, the plurality of hydraulically extensible legs extending between the base and roof canopy units of each support are arranged as relatively forwardly and relatively rear-wardly leg units such that a passage or walkway is defined between .~
the leg units of each support when, in use, the roof supports are installed along the longwall face, the passage or walkway extends along at least a portion of the longwall face.
Preferably, the set of relatively forwardly located legs of said adjacent supports comprises a pair of legs each leg having a preselected load capacity.
Preferably, the single relatively rearwardly located leg has a Z~66~
load capacity greater than said preselected load capacity.
Preferably, the single relatively rearwardly located leg has a load capacity at least equal to the sum of the load capacity of the relatively rearward set of legs.
S Preferably, the relatively rearwardly located single leg is located on the fore and aft centre line of the support, when viewed in plan, the pair of legs constituting the relatively forwardly located set of legs being arranged on opposite sides of the fore and aft centre line.
The present invention also provides an underground mine roof support for use in the above defined support system comprising a base unit, a roof canopy unit and a plurality of hydraulically extensible legs extending between the base and roof canopy units, at least some of the legs being arranged as a relatively ~orwardly located pair of legs and a relatively rearwardly located single leg.
Preferably, each leg constituting the relatively fo~wardly located pair of legs has a preselected loading capacity, the load capacity of the relativelY rearwardly located single leg being greater than the said preselected load capacity.
Preferably, the load capacity of the relatively rearwardly located single leg is at least equal to the sum of the load capacity of the pair of relatively forwardly located legs.
Preferably, the relatively rearwardly located single leg is located on the fore and aft centre line of the support, when viewed in plan, the pair of legs constituting the relatively forwardly . ~ .-: . ~ . -. : .
.. .
~lZ~661 located set of legs being arranged on opposite sides of the fore and aft centre line.
By way of example only, one embodiment of the present invention will be described with reference to the accompanying drawings, in which:-Figure 1 is an incomplete plan of one end of a longwall faceinstallation in an underground mine showing a part of a service roadway to the longwall face and a part of a mine roof support system installed on the longwall face;
Figure 2 is a rear view of Figure l;
Figure 3 shows a portion of Figure 2 drawn on an enlarged scale;
Figure 4 shows a portion of Figure :L drawn on an enlarged scale;
Figure 5 is an incomplete view look.lng in the direction of arrow A of Figure 4;
Figure 6 is an incomplete view looking in the direction of arrow B of Figure 4;
Figure 7 is a diagrammatic plan of the end of the longwall face installation showing the roof support system in a first operational mode;
Figure R i~ a diagrammatic plan similar to Figure 7, but showing the roof support system in a second operational mode;
Figure 9 is a diagrammatic plan similar to Figure 7 but showing the roof support system in a third operational mode; and ~Z9~
Figure 10 is a diagrammatic plan similar to Figure 7 but showing the roof support system in a fourth operational mode.
Figures 1 and 2 show an underground mine roof support system comprising a plurality of different roof supports 1, 51, 52, 53, 54, 5 55 and 56 arranged in side-by-side relationship and supporting or containing the mine roof 60 adjacent to one end of a longwall face having a working face 50 from which mineral is extracted by a winning machine (not shown in the drawings) which traverses to and fro along a path defined by an armoured Plexible conveyor 81 extending along 10 the longwall face. A service roadway 62 to the longwall face ls supported by arch type roof supports 6~. In operation, as the working face is advanced by the winning machîne the roadway is extended in increments by excavation of the ripping lip 65 which in Figure 1 is shown supported on rearwardly extensible cantilever beams 15 16 and 66 extending from the installed roof supports 1 and 51. The roof support 1 is provided with a rearwardly extensible hinged flap element which is omitted in the Figures but which would be in a raised roof supporting mode supporting the ripping lip 6~.
In addition to the rearwardly extensible cantilever beams 66 20 each of the three adjacent roof supports 51 comprises a base unit 70 extending rearwardly from adjacent to the wor~ing face 50, a roof engaging canopy unit 72, also extending rearwardly from adjacent to the working face, and three hydraulically extensible legs 73, 1?3 mounted on the base unit 70 to urge the canopy unit 7~ into a roof 25 supporting mode. The -t-.lo relatively forwardly located legs are ~LZ~6~L
arranged as a pair of legs mounted on opposite sides of the fore and aft centre line 200 (see Figure 4) of the support as seen in plan.
The remaining leg 173 is arranged as a relatively rearwardly located single leg mounted on the ~ore and aft centre line 200. A passage S or walkway 210 is defined between the forwardly and rearwardly located legs, in use the passage or walkway extending along the length of the longwall face, between the forwardly and rearwardly located legs of all the supports. Thus, mine operators are able to travel along the longwall face in a direction generally parallel with the working face.
Each of the relatively forwardly located legs 73 has a preset, preselected load carrying capacity. In operation the legs 73 are set to yield when the downward force 0xerted by the overhead strata on the associated portion of the roof canopy unit exceeds the preselected load carrying capacity. The relatively rearwardly located single leg ~73 has a preset load carrying capacity greater than the preselected capacity of the legs 73 and in a typical installation the loading carrying capacity of the single leg 173 is at least equal to the sum of the total load carrying capacity of the pair of relatively forwardly located legs.
The legs 73 are mounted in mounting units 211 provided on the base units 70 and the legs 173 are mounted in mounting units 212 also provided on the base units 70.
A forwardly extensible cantilever beam 74 extends towards the working face to support the mine roof which has been newly exposed by passage of the winning machine cutter. As shown in Figure 1 and 5 - 9 - ~z~
the two supports 51 nearest to the end of the longwall face are provided to support the mine roof in the vicinity of a drive arrangement 80 for the previously mentioned armoured conveyor 81 which extends along the longwall face providing a path for the mining S machine and conveying material won by the mining machine cutter towards the stage loader conveyor 2 which conveys the won material into the roadway 62. Figure 6 shows the support 51 relatively remote from the end of the longwall face, as seen in the drawing the legs 73, 173 are located in the same positions relatively to each other but are more forwardly with respect to the canopy unit than is the case with the support shown in Figure 5. As can be seen in Figure 3 and 4 the distance D (ie. the width of the gap between adjacent single legs 173 of adjacent supports 51)defines a passageway extending from the passage or walkway 210 towards the servlce roadway 62 and towards packing areas 82 within which is installed packing equipment 84 described in more detail later in the specification. As seen in Figure 3 the distance D
is considerably greater than the distance E between the legs 73 of one support or the distance F between adjacent legs 73 of adjacent supports.
In consequence access to the passage or walkway 210 is facilitated.
It should be noted that the access passageway is obtained between the two relatively rearward single legs and the base and roof canopy units without having to increase the overall width of the roof canopy unit Thus, when the support is advanced and the roof canopy is lowered into its advancing mode, the resulting area of expose~ mine roof is within that normally accepted as safe and roof falls tend to be avoided during ~2~
advancement of the supports.
Adjacent to the three roof supports 51 are five roof supports 52 which are arranged along the length of a pack 82 built from rock debris produced by excavation of the ripping lip 65 to extend the roadway 62, the pack helping to support the rock strata adjacent to the roadway : 62. The pack is built in a part of the void left by the advancing longwall face and material produced by each excavation of the ripping lip 65 is conveyed into the pack by a series of hydraulically actuated reciprocating paddles 84 mounted on the back of the supports 52 beneath the rearwardly extensible cantilever beams 85 extending from roof engaging canopies 86 of the supports 52. Each canopy 86 is urged into a roof engaging mode by four hydraulic legs 87, 187 carried on a floor mounted base component 88. The legs 87 are arranged in relatively forwardly located pairs and the legs 187 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. Each support 52 also comprises a forwardly extensible cantilever beam 89 to support mine roof newly exposed by the passage of the mining machine cutter.
Adjacent to the end of the pack remote from the roadway 62 three buttress chock supports 53, 54 2nd 55 are installed. The chock 53 extends rearwardly to support the mine roof in the vicinity of the end of the pack adjacent to a goaf or void 90 left behind the advancing longwall face. As the face advances -the mine roof is allowed to collapse into the goaf. The buttress chock supports 53 and 54 have 25 articulatedly constructed roof canopies 91, 92 enabling the relatively ~' :
~L~2~6~
elongated canopies to negotiate undulations in the mine roof when the associated supports are advanced. Each of the buttress chock supports comprises a floor mounted base component 93 supporting a plurality of hydraulic legs 94, 194, 294, arranged to urge associa-ted roof canopies 91, 92 or 95 into roof supporting modes. The legs 94 are arranged in relatively forwardly located pairs and the legs 194 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. In addition, a further pair of relatively rearwardly located legs 294 are provided on 53 and 54.
Each buttress chock support also comprises a flushing shield 96 tending to prevent passage of broken rock material from the collapsing goaf towards the working face and a forwardly extensible cantilever beam 97.
The remaining roof support 56 shown in Figures 1 and 2 is one of a plurality of roof supports installecl along the length of the longwall face and each comprising a floor mounted base component 98, a roof engaging canopy 99 and a plurality of hydraulic legs 100, 300, 400, carried on the base arranged to urge the canopy towards a roof supporting mode. The legs 100 are arranged in relatively forwardly located pairs and the legs 300 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. In addition a further pair of relatively rearwardly located legs 400 are provided. Each roof support 56 also comprises a forwardly extensible cantilever beam 101 and a flushing shield 102.
Each of the roof supports 51 to 56 is provided with a hydraulic - 12 - ~ 6~
advancing ram connected between the conveyor 81 and the associated -, . . . . . . . . .
supports. These advancing rams enable the conveyor 81 or a selected portion of the conveyor to be advanced towards the working face when the roof suPports are anchored in installed set roof supporting modes.
Also the advancing rams enable each support in turn to be advanced towards the working face, during its advancement each support is released from its roof supporting mode by retraction of the hydraulic props. The conveyor which is retained in an advanced position by roof supporting set supports adjacent to the advancing support, provides the anchorage again twhich the support is advanced.
The advancin8 means for the roof support 1 comprises two hydraulic rams 105 which extend from the base components to the two outer sec-tions of the unit 6 to brackets 106 fixedly secured to the stage loader conveyor 2. Thus, in operation when it is desired to advance the stage loader conveyor 3 towards the wor~cing face, -the roof engaging canopy 13 of the unit 5 is released from its roof supporting mode by retraction of the props 12, the advancing rams 106 then are activated to urge the stage loader conveyor forward together with the unit 5 which as previously stated is fixedly mounted with respect to the stage loader conveyor. Once the stage loader is advanced to a desired position the unit 5 is reset to its roof supporting mode to thereby anchor the stage loader conveyor which then - -~2~
provides an anchorage for advancement of the outer unit 6 by suitable activation of the advancing rams 106.
Throughout advance of the units 5 and 6 the currently advancing unit 5 or 6 is guided by the anchored unit 6 or 5. In a typical installation the stage loader conveyor is fixedly secured to the discharge end of the face conveyor. In such an installation the stage loader conveyor is advanced in unison with the adjacent end portion of the face conveyor and activation of the advancing rams 106 to advance the stage loader conveyor is carried out simultaneously with activation of the advancing rams of other supports arranged along the face.
In operation, as the machine traverses along the longwall face winning strips of mineral from the working face with the machine's cutter arranged to win a desired web on each cutting traverse, the roof supports are advanced in a controlled preselected sequence to ensure the newly exposed mine roof is adequately supported. The multi-stage advancement sequence of the supports now will be described with reference to Figures 7, 8, 9 and 10.
It will be appreciated that Figures 7, 8, 9 and 10 show the support layout diagrammatically and for the sake of clarity the conveyor, mining machine and support advancing means are not shown.
In addition, only three supports 52 are shown in Figures 7 to 10 instead of five as shown in Figures 1 and 2. Support 56 is omitted from Figure 7 to 10.
Figure 7 shows the situation with all the roof supports installed ~, , ,~, . . .
in an advanced mode set immediately adjacent to the working face 50.
The support 1 is shown in its first installed set position with the two units 5 and 6 advanced by an equal amount. The supports Sl to 55 are fully advanced and the service roadway 62 is fùlly extended up to the rearmost end of the support canopies 13 and 23. In addition, the pack 82 is fully extended up to the rearmost ends of the roof canopies of the supports 52. No support has an outwardly extending cantilever beam.
Figure 8 shows the first stage of advancement when the machine has just completed its cutting traverse along the face cutting towards the end of the face shown in the drawing ie. in the direction indicated by arrow x. The depth of the web of mineral won by the cutter on the traverse is indicated by distance a in Figure 8.
Immediately upon the machine passing a roof support, eg. support 55, the forwardly extensible cantilever beam, eg. beam is extended to support the newly exposed mine roof. This procedure is followed until the machine has cut its way to the extreme end of the longwall face and the cutter has reached the rib side 101.
Upon the machine reaching the end of the cutting tra~erse the unit 5 of the support 1 is released from its roof supporting mode as previously explained and with the unit 6 providing an anchor unit, the advancing rams 105 are activated to urge the unit 5, the stage loader conveyor 2 and the end portion of the face conveyor 81 towards the newly advanced working face. The advancing rams of the other supports in the vicinity of the face end simulataneously are activated to urge ' ~' , ' !
- 15 - ~2~
the end portion of the face conveyor 81 towards the working face and the machine is shuttled to and fro enabling the cutter to progressively win mineral from the working face until it is advanced by a distance equal to the desired web depth a. Once the machine's cutter is advanced to the desired position the unit 5 is reset to the mine roof in a second installed set position in advance of the unit 6 which is still in the first installed set position. With the unit 5 in the second installed set position the rearwardly extensible cantilever beam 16 is extended to support the otherwise exposed mine roof in between the rearward ends of the roof beams 23 of the set unit 6.
Once the unit 5 is advanced to the second installed set position the other face supports 55 to 51 are advanced in sequence the forwardly directed oantilever beams being withdrawn in sequenoe during advancement of the associated roof support. ~hen all the face supports are advanced the second stage of advancement of the support 1 commences and the unit 6 of the support 1 is released from its roof supporting mode and advancsd to the second installed set position.
As the unit 6 is advanced the rearwardly extensible cantilever beam 16 is withdrawn. The support layo~lt now is as shown in Figure 9 with the leading ends of all the supports set immediately adjacent to the working face. As shown in the drawing with the unit 6 in the second installed set position the hinged flap element 27 is raised into a mine roof supporting mode by activation of the inclined rams 30. Also as seen in Figure 9 the ripping lip 65 is supported by the cantilever ~Z~6~
beam 66 as well as the hinged flap element and the pack area is supported by the cantilever beams 85 and the buttress chock supports.
With the supports in the installed set position as indicated in Figure 9 the machine starts a cutting traverse along the face cutting in a direction opposite to that indicated by arrow x.
Upon the machine passing the roof supports, 51, 52, 53, 5~ and 55 the forwardly directed cantilever beams 74, 89 and 97 are advanced to provide adequate roof support to the newly exposed mine roof.
Once the machine is clear of the face end, the third stage of advancement of the support 1 commences and the end portion of the face conveyor 81 together with the stage loader conveyor 2 and unit 5 are advanced by a distance equal to the desired cutting web of the cutter and the roof canopy 13 is immediately adjacent to the working face. The unit 5 then is reset to the mine roof in a third installed set position in a~vance of the unit 6 which remains in the second installed set position with the hingecl flap element 27 in a raised roof supporting mode. The support layout is as shown in Figure 10.
The ripping lip and pack area is supported by the rearwardly directed cantilever beams.
Upon the mine operatives being ready to commence the excavation of rock from the ripping lip to extend the roadway 62, the supports 1 and 52 are advanced to a position as shown in Figure 7 with the associated roof canopies immediately adjacent to the working face.
The unit 6 is advanced during the fourth stage of advancement until it reaches the third installed set position. The rearwardly directed : . .
~Z~6~
cantilever beams 16 and 66 are withdrawn on to the roof canopies and the hinged flap element 27 is lowered to permit rock to be excavated from the ripping lip 65 to extend the roadway 62, the excavated ripping lip being equal to two web depths won by the face machine's cutter.
Also, the cantilever beams 85 are withdrawn when the pack 82 is extended up to the rear of the rooP canopies of supports 52. The position now is substantially as shown in Figure 7 and the whole advancement operation is repeated when the machine once again reaches the face end shown in the drawings.
From the above description it will be appreciated that the present invention provides a mine roof support which tends to minimise delays to the face machine's cutting operation.
Also it will be appreciated that the mine roof support system provides a plurality of roof supports defining a passage or walkway for a mine operator to travel along substantially the full length of the longwall face. The passage is deYined irrespective of the operational modes of advance o~ the supports. In addition, the mine operator always is permitted access to the passage via the gaps defined between the relatively rearwardly located single legs and the base and roof canopy units of the supports 51. Access is permitted from the service roadway 62 and from the packing area for the pack forming equipment 8~.
' :. ; ' t
MINE ROOF SUPPORT SYSTEMS AND MINE ROOF SUPPORTS FOR USE IN SUCH
SYSTEMS
his invention relates to underground mine roof support systems and to mine roof supports for use with such system In particular, although not exclusively, the present invention relates to underground mine roof support systems for use on longwall faces in regions adjacent to the junctions of the longwall faces with services roadways where it frequently is necessary for mine operators to gain aocess to the longwall face from the service roadway and/or from equipment installed in pack areas adjacent to ; the services roadway, for example, packing equipment arranged to ~; .
build packs of rock debris generated during the extension of the roadway, the packs tending to provide a buttress for settling strata in the vicinity of the roadway.
Typically, previously known mine roof support systems associated with a junction between an advancing longwall face and : 15 a service roadway, included a plurality~ of roof support units arranged in side by side relationship along the length o~ the longwall face and each comprising a rearwardly extending base unit constituted by a pair of laterally spaced floor mounted skids, a rearwardly extending roof canopy unit provided with forwardly and rearwardly extensible roof beams or bars for supporting or containing :, the mine roof in the vicinity of a ripping lip which is constituted by the area of mine roof immediately in advance of the roadway and which is excavated to extend or advance the roadway, and also in the vicinity of the mine roof associated with the previously mentioned pack areas.
Each roof canopy unit is supported from its associated base unit by means of four or more hydraulically extensible legs or jacks arranged as a pair of rela-tively forwardly located, laterally spaced legs and as a pair of relatively rearwardly located, laterally spaced legs. Each pair of legs is mounted in a mounting unit bridging the two previously men-tioned floor mounted skids of the base unit such that, in use, when theplurality of roof supports are installed in side-by-side relationship along the length of longwall face a PaSsage or walkway for mine operators is defined between the two rowsof forwardly and rearwardly located legs.
` If a support comprises more than two pa:irs of legs, the further legs are arranged as a pair of laterally spaced :Legs mounted relatively rearwardly of the previously mentioned relatively rearwardly legs. Both PairS of relatively rearwardly legs may be mounted in a common mounting unit bridging the floor mounted skids of the base unit. Each of the hydraulic-; ally extensible legs on each support unit has the same preset, preselected loading capacity whereby each leg applied the same loading reaction tothe roof canopy unit and is set to yield when the load tends to increase above the preselected loading capacity.
With such a prior known mine roof support system the mounting units for the relatively rearwardly located pairs of legs tend to prohi~it or hinder the passage of mine operators between legs in each : . ~
29~6~
pair. Moreover, in order to adequately support the mine roof along the longwall face it is necessary to have each roof support installed closely adjacent to its neighbours so that adjacent rearwardly located legs on two adjacent supports tend to be so close to one another that the mine operator is prohibited from safely passing between two adjacent installed supports. Thus, a disadvantage of such prior known mine roof support systems is that access for mine operators to the aforementioned passage or walkway from the service roadway or from equipment is difficult, especially if bulky equipment or apparatus is to be brought into the region of the passage or walkway. Such bulky equipment or apparatus, for example, may comprise heavy conveyor equipment or a loaded stretcher.
It is an object of the present invention to provide a mine roof support system which tends to overcome or reduce the above mentioned disadvantage and which tends to provide relatively easier and safer access to the passage or walkway defined by the roo supports and extending generally along the longwall face.
The present invention provides an underground mine roof support system for a longwall face having a winning machine traversable to and fro along a path adjacent to the working face, and having at least one service roadway for the longwall face, the system being associated with a portion of the longwall face adja-cent to the junction of the longwall face with said service road-way, the system comprising a plurality of advanceable roof supports which, in use, are arranged in a side-by-side relationship and which, in use, are advanced in sequence towards the newly exposed working face as mineral is extracted by the winning machine, each ~Z~6~
support having a base unit, a roof canopy unit provided with a rearwardly extendable beam capable of being extended from the rear of the roof canopy towards the service roadway, and a plurality of hydraulically extensible legs extending between the base and roof canopy units, which units, in use, extend rearwardly from adjacent to the working face, at least two adjacent roof supports comprising a set of relatively forwardly located legs and a relatively rear-wardly located single leg such that, in use, an access passageway is defined between the two relatively rearwardly single legs and the base and roof canopy units of said two adjacent roof supports, the passageway temporarily being extendable towards the service roadway upon advance of the associated supports by the rearwardly extendable beams.
Advantageously, the plurality of hydraulically extensible legs extending between the base and roof canopy units of each support are arranged as relatively forwardly and relatively rear-wardly leg units such that a passage or walkway is defined between .~
the leg units of each support when, in use, the roof supports are installed along the longwall face, the passage or walkway extends along at least a portion of the longwall face.
Preferably, the set of relatively forwardly located legs of said adjacent supports comprises a pair of legs each leg having a preselected load capacity.
Preferably, the single relatively rearwardly located leg has a Z~66~
load capacity greater than said preselected load capacity.
Preferably, the single relatively rearwardly located leg has a load capacity at least equal to the sum of the load capacity of the relatively rearward set of legs.
S Preferably, the relatively rearwardly located single leg is located on the fore and aft centre line of the support, when viewed in plan, the pair of legs constituting the relatively forwardly located set of legs being arranged on opposite sides of the fore and aft centre line.
The present invention also provides an underground mine roof support for use in the above defined support system comprising a base unit, a roof canopy unit and a plurality of hydraulically extensible legs extending between the base and roof canopy units, at least some of the legs being arranged as a relatively ~orwardly located pair of legs and a relatively rearwardly located single leg.
Preferably, each leg constituting the relatively fo~wardly located pair of legs has a preselected loading capacity, the load capacity of the relativelY rearwardly located single leg being greater than the said preselected load capacity.
Preferably, the load capacity of the relatively rearwardly located single leg is at least equal to the sum of the load capacity of the pair of relatively forwardly located legs.
Preferably, the relatively rearwardly located single leg is located on the fore and aft centre line of the support, when viewed in plan, the pair of legs constituting the relatively forwardly . ~ .-: . ~ . -. : .
.. .
~lZ~661 located set of legs being arranged on opposite sides of the fore and aft centre line.
By way of example only, one embodiment of the present invention will be described with reference to the accompanying drawings, in which:-Figure 1 is an incomplete plan of one end of a longwall faceinstallation in an underground mine showing a part of a service roadway to the longwall face and a part of a mine roof support system installed on the longwall face;
Figure 2 is a rear view of Figure l;
Figure 3 shows a portion of Figure 2 drawn on an enlarged scale;
Figure 4 shows a portion of Figure :L drawn on an enlarged scale;
Figure 5 is an incomplete view look.lng in the direction of arrow A of Figure 4;
Figure 6 is an incomplete view looking in the direction of arrow B of Figure 4;
Figure 7 is a diagrammatic plan of the end of the longwall face installation showing the roof support system in a first operational mode;
Figure R i~ a diagrammatic plan similar to Figure 7, but showing the roof support system in a second operational mode;
Figure 9 is a diagrammatic plan similar to Figure 7 but showing the roof support system in a third operational mode; and ~Z9~
Figure 10 is a diagrammatic plan similar to Figure 7 but showing the roof support system in a fourth operational mode.
Figures 1 and 2 show an underground mine roof support system comprising a plurality of different roof supports 1, 51, 52, 53, 54, 5 55 and 56 arranged in side-by-side relationship and supporting or containing the mine roof 60 adjacent to one end of a longwall face having a working face 50 from which mineral is extracted by a winning machine (not shown in the drawings) which traverses to and fro along a path defined by an armoured Plexible conveyor 81 extending along 10 the longwall face. A service roadway 62 to the longwall face ls supported by arch type roof supports 6~. In operation, as the working face is advanced by the winning machîne the roadway is extended in increments by excavation of the ripping lip 65 which in Figure 1 is shown supported on rearwardly extensible cantilever beams 15 16 and 66 extending from the installed roof supports 1 and 51. The roof support 1 is provided with a rearwardly extensible hinged flap element which is omitted in the Figures but which would be in a raised roof supporting mode supporting the ripping lip 6~.
In addition to the rearwardly extensible cantilever beams 66 20 each of the three adjacent roof supports 51 comprises a base unit 70 extending rearwardly from adjacent to the wor~ing face 50, a roof engaging canopy unit 72, also extending rearwardly from adjacent to the working face, and three hydraulically extensible legs 73, 1?3 mounted on the base unit 70 to urge the canopy unit 7~ into a roof 25 supporting mode. The -t-.lo relatively forwardly located legs are ~LZ~6~L
arranged as a pair of legs mounted on opposite sides of the fore and aft centre line 200 (see Figure 4) of the support as seen in plan.
The remaining leg 173 is arranged as a relatively rearwardly located single leg mounted on the ~ore and aft centre line 200. A passage S or walkway 210 is defined between the forwardly and rearwardly located legs, in use the passage or walkway extending along the length of the longwall face, between the forwardly and rearwardly located legs of all the supports. Thus, mine operators are able to travel along the longwall face in a direction generally parallel with the working face.
Each of the relatively forwardly located legs 73 has a preset, preselected load carrying capacity. In operation the legs 73 are set to yield when the downward force 0xerted by the overhead strata on the associated portion of the roof canopy unit exceeds the preselected load carrying capacity. The relatively rearwardly located single leg ~73 has a preset load carrying capacity greater than the preselected capacity of the legs 73 and in a typical installation the loading carrying capacity of the single leg 173 is at least equal to the sum of the total load carrying capacity of the pair of relatively forwardly located legs.
The legs 73 are mounted in mounting units 211 provided on the base units 70 and the legs 173 are mounted in mounting units 212 also provided on the base units 70.
A forwardly extensible cantilever beam 74 extends towards the working face to support the mine roof which has been newly exposed by passage of the winning machine cutter. As shown in Figure 1 and 5 - 9 - ~z~
the two supports 51 nearest to the end of the longwall face are provided to support the mine roof in the vicinity of a drive arrangement 80 for the previously mentioned armoured conveyor 81 which extends along the longwall face providing a path for the mining S machine and conveying material won by the mining machine cutter towards the stage loader conveyor 2 which conveys the won material into the roadway 62. Figure 6 shows the support 51 relatively remote from the end of the longwall face, as seen in the drawing the legs 73, 173 are located in the same positions relatively to each other but are more forwardly with respect to the canopy unit than is the case with the support shown in Figure 5. As can be seen in Figure 3 and 4 the distance D (ie. the width of the gap between adjacent single legs 173 of adjacent supports 51)defines a passageway extending from the passage or walkway 210 towards the servlce roadway 62 and towards packing areas 82 within which is installed packing equipment 84 described in more detail later in the specification. As seen in Figure 3 the distance D
is considerably greater than the distance E between the legs 73 of one support or the distance F between adjacent legs 73 of adjacent supports.
In consequence access to the passage or walkway 210 is facilitated.
It should be noted that the access passageway is obtained between the two relatively rearward single legs and the base and roof canopy units without having to increase the overall width of the roof canopy unit Thus, when the support is advanced and the roof canopy is lowered into its advancing mode, the resulting area of expose~ mine roof is within that normally accepted as safe and roof falls tend to be avoided during ~2~
advancement of the supports.
Adjacent to the three roof supports 51 are five roof supports 52 which are arranged along the length of a pack 82 built from rock debris produced by excavation of the ripping lip 65 to extend the roadway 62, the pack helping to support the rock strata adjacent to the roadway : 62. The pack is built in a part of the void left by the advancing longwall face and material produced by each excavation of the ripping lip 65 is conveyed into the pack by a series of hydraulically actuated reciprocating paddles 84 mounted on the back of the supports 52 beneath the rearwardly extensible cantilever beams 85 extending from roof engaging canopies 86 of the supports 52. Each canopy 86 is urged into a roof engaging mode by four hydraulic legs 87, 187 carried on a floor mounted base component 88. The legs 87 are arranged in relatively forwardly located pairs and the legs 187 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. Each support 52 also comprises a forwardly extensible cantilever beam 89 to support mine roof newly exposed by the passage of the mining machine cutter.
Adjacent to the end of the pack remote from the roadway 62 three buttress chock supports 53, 54 2nd 55 are installed. The chock 53 extends rearwardly to support the mine roof in the vicinity of the end of the pack adjacent to a goaf or void 90 left behind the advancing longwall face. As the face advances -the mine roof is allowed to collapse into the goaf. The buttress chock supports 53 and 54 have 25 articulatedly constructed roof canopies 91, 92 enabling the relatively ~' :
~L~2~6~
elongated canopies to negotiate undulations in the mine roof when the associated supports are advanced. Each of the buttress chock supports comprises a floor mounted base component 93 supporting a plurality of hydraulic legs 94, 194, 294, arranged to urge associa-ted roof canopies 91, 92 or 95 into roof supporting modes. The legs 94 are arranged in relatively forwardly located pairs and the legs 194 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. In addition, a further pair of relatively rearwardly located legs 294 are provided on 53 and 54.
Each buttress chock support also comprises a flushing shield 96 tending to prevent passage of broken rock material from the collapsing goaf towards the working face and a forwardly extensible cantilever beam 97.
The remaining roof support 56 shown in Figures 1 and 2 is one of a plurality of roof supports installecl along the length of the longwall face and each comprising a floor mounted base component 98, a roof engaging canopy 99 and a plurality of hydraulic legs 100, 300, 400, carried on the base arranged to urge the canopy towards a roof supporting mode. The legs 100 are arranged in relatively forwardly located pairs and the legs 300 are arranged in relatively rearwardly located pairs such that the passage or walkway 210 is defined between the pairs of legs. In addition a further pair of relatively rearwardly located legs 400 are provided. Each roof support 56 also comprises a forwardly extensible cantilever beam 101 and a flushing shield 102.
Each of the roof supports 51 to 56 is provided with a hydraulic - 12 - ~ 6~
advancing ram connected between the conveyor 81 and the associated -, . . . . . . . . .
supports. These advancing rams enable the conveyor 81 or a selected portion of the conveyor to be advanced towards the working face when the roof suPports are anchored in installed set roof supporting modes.
Also the advancing rams enable each support in turn to be advanced towards the working face, during its advancement each support is released from its roof supporting mode by retraction of the hydraulic props. The conveyor which is retained in an advanced position by roof supporting set supports adjacent to the advancing support, provides the anchorage again twhich the support is advanced.
The advancin8 means for the roof support 1 comprises two hydraulic rams 105 which extend from the base components to the two outer sec-tions of the unit 6 to brackets 106 fixedly secured to the stage loader conveyor 2. Thus, in operation when it is desired to advance the stage loader conveyor 3 towards the wor~cing face, -the roof engaging canopy 13 of the unit 5 is released from its roof supporting mode by retraction of the props 12, the advancing rams 106 then are activated to urge the stage loader conveyor forward together with the unit 5 which as previously stated is fixedly mounted with respect to the stage loader conveyor. Once the stage loader is advanced to a desired position the unit 5 is reset to its roof supporting mode to thereby anchor the stage loader conveyor which then - -~2~
provides an anchorage for advancement of the outer unit 6 by suitable activation of the advancing rams 106.
Throughout advance of the units 5 and 6 the currently advancing unit 5 or 6 is guided by the anchored unit 6 or 5. In a typical installation the stage loader conveyor is fixedly secured to the discharge end of the face conveyor. In such an installation the stage loader conveyor is advanced in unison with the adjacent end portion of the face conveyor and activation of the advancing rams 106 to advance the stage loader conveyor is carried out simultaneously with activation of the advancing rams of other supports arranged along the face.
In operation, as the machine traverses along the longwall face winning strips of mineral from the working face with the machine's cutter arranged to win a desired web on each cutting traverse, the roof supports are advanced in a controlled preselected sequence to ensure the newly exposed mine roof is adequately supported. The multi-stage advancement sequence of the supports now will be described with reference to Figures 7, 8, 9 and 10.
It will be appreciated that Figures 7, 8, 9 and 10 show the support layout diagrammatically and for the sake of clarity the conveyor, mining machine and support advancing means are not shown.
In addition, only three supports 52 are shown in Figures 7 to 10 instead of five as shown in Figures 1 and 2. Support 56 is omitted from Figure 7 to 10.
Figure 7 shows the situation with all the roof supports installed ~, , ,~, . . .
in an advanced mode set immediately adjacent to the working face 50.
The support 1 is shown in its first installed set position with the two units 5 and 6 advanced by an equal amount. The supports Sl to 55 are fully advanced and the service roadway 62 is fùlly extended up to the rearmost end of the support canopies 13 and 23. In addition, the pack 82 is fully extended up to the rearmost ends of the roof canopies of the supports 52. No support has an outwardly extending cantilever beam.
Figure 8 shows the first stage of advancement when the machine has just completed its cutting traverse along the face cutting towards the end of the face shown in the drawing ie. in the direction indicated by arrow x. The depth of the web of mineral won by the cutter on the traverse is indicated by distance a in Figure 8.
Immediately upon the machine passing a roof support, eg. support 55, the forwardly extensible cantilever beam, eg. beam is extended to support the newly exposed mine roof. This procedure is followed until the machine has cut its way to the extreme end of the longwall face and the cutter has reached the rib side 101.
Upon the machine reaching the end of the cutting tra~erse the unit 5 of the support 1 is released from its roof supporting mode as previously explained and with the unit 6 providing an anchor unit, the advancing rams 105 are activated to urge the unit 5, the stage loader conveyor 2 and the end portion of the face conveyor 81 towards the newly advanced working face. The advancing rams of the other supports in the vicinity of the face end simulataneously are activated to urge ' ~' , ' !
- 15 - ~2~
the end portion of the face conveyor 81 towards the working face and the machine is shuttled to and fro enabling the cutter to progressively win mineral from the working face until it is advanced by a distance equal to the desired web depth a. Once the machine's cutter is advanced to the desired position the unit 5 is reset to the mine roof in a second installed set position in advance of the unit 6 which is still in the first installed set position. With the unit 5 in the second installed set position the rearwardly extensible cantilever beam 16 is extended to support the otherwise exposed mine roof in between the rearward ends of the roof beams 23 of the set unit 6.
Once the unit 5 is advanced to the second installed set position the other face supports 55 to 51 are advanced in sequence the forwardly directed oantilever beams being withdrawn in sequenoe during advancement of the associated roof support. ~hen all the face supports are advanced the second stage of advancement of the support 1 commences and the unit 6 of the support 1 is released from its roof supporting mode and advancsd to the second installed set position.
As the unit 6 is advanced the rearwardly extensible cantilever beam 16 is withdrawn. The support layo~lt now is as shown in Figure 9 with the leading ends of all the supports set immediately adjacent to the working face. As shown in the drawing with the unit 6 in the second installed set position the hinged flap element 27 is raised into a mine roof supporting mode by activation of the inclined rams 30. Also as seen in Figure 9 the ripping lip 65 is supported by the cantilever ~Z~6~
beam 66 as well as the hinged flap element and the pack area is supported by the cantilever beams 85 and the buttress chock supports.
With the supports in the installed set position as indicated in Figure 9 the machine starts a cutting traverse along the face cutting in a direction opposite to that indicated by arrow x.
Upon the machine passing the roof supports, 51, 52, 53, 5~ and 55 the forwardly directed cantilever beams 74, 89 and 97 are advanced to provide adequate roof support to the newly exposed mine roof.
Once the machine is clear of the face end, the third stage of advancement of the support 1 commences and the end portion of the face conveyor 81 together with the stage loader conveyor 2 and unit 5 are advanced by a distance equal to the desired cutting web of the cutter and the roof canopy 13 is immediately adjacent to the working face. The unit 5 then is reset to the mine roof in a third installed set position in a~vance of the unit 6 which remains in the second installed set position with the hingecl flap element 27 in a raised roof supporting mode. The support layout is as shown in Figure 10.
The ripping lip and pack area is supported by the rearwardly directed cantilever beams.
Upon the mine operatives being ready to commence the excavation of rock from the ripping lip to extend the roadway 62, the supports 1 and 52 are advanced to a position as shown in Figure 7 with the associated roof canopies immediately adjacent to the working face.
The unit 6 is advanced during the fourth stage of advancement until it reaches the third installed set position. The rearwardly directed : . .
~Z~6~
cantilever beams 16 and 66 are withdrawn on to the roof canopies and the hinged flap element 27 is lowered to permit rock to be excavated from the ripping lip 65 to extend the roadway 62, the excavated ripping lip being equal to two web depths won by the face machine's cutter.
Also, the cantilever beams 85 are withdrawn when the pack 82 is extended up to the rear of the rooP canopies of supports 52. The position now is substantially as shown in Figure 7 and the whole advancement operation is repeated when the machine once again reaches the face end shown in the drawings.
From the above description it will be appreciated that the present invention provides a mine roof support which tends to minimise delays to the face machine's cutting operation.
Also it will be appreciated that the mine roof support system provides a plurality of roof supports defining a passage or walkway for a mine operator to travel along substantially the full length of the longwall face. The passage is deYined irrespective of the operational modes of advance o~ the supports. In addition, the mine operator always is permitted access to the passage via the gaps defined between the relatively rearwardly located single legs and the base and roof canopy units of the supports 51. Access is permitted from the service roadway 62 and from the packing area for the pack forming equipment 8~.
' :. ; ' t
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
Case 4286/CAN
1. An underground mine roof support system for a longwall face having a winning machine traversable to and fro along a path adjacent to the working face, and having at least one service roadway for the longwall face, the system being associated with a portion of the longwall face adjacent to the junction of the longwall face with said service roadway, the system comprising a plurality of advanceable roof supports which, in use, are arranged in a side-by-side relationship and which, in use, are advanced in sequence towards the newly exposed working face as mineral is extracted by the winning machine, each support having a base unit, a roof canopy unit provided with a rearwardly extendable beam capable of being extended from the rear of the roof canopy towards the service roadway, and a plurality of hydraulically extensible legs extending between the base and roof canopy units,which units, in use, extend rearwardly from adjacent to the working face, at least two adjacent roof supports comprising a set of relatively forwardly located legs and a relatively rearwardly located single leg such that, in use, an access passageway is defined between the two relatively rearwardly single legs and the base and roof canopy units of said two adjacent roof supports, the passageway temporarily being extendable towards the service roadway upon advance of the associated supports by the rearwardly extendable beams.
2. A system as claimed in claim 1 in which the plurality of hydraulically extensible legs extending between the base and roof canopy units of each support are arranged as relatively forward and relatively rearward leg units such that a passage or walkway is defined between the leg units of each support when, in use, the roof supports are installed along the longwall face, the passage or walkway extends along at least a portion of the longwall face.
3. A system as claimed in claim 2 in which the set of relatively forwardly located legs of said adjacent supports comprises a pair of legs each leg having a preselected load capacity.
4. A system as claimed in claim 3, in which the relatively rearwardly located single leg of each said adjacent roof support has a load capacity greater than said preselected load capacity.
5. A system as claimed in claim 4, in which the relatively rearwardly located single leg has a load capacity at least equal to the sum of the load capacity of the relatively forwardly located set of legs.
6. A system as claimed in claim 5, in which the relatively rearwardly located single leg is located on the fore and aft centre line of the support, when viewed in plan, the pair of legs constituting the relatively forwardly located set of legs being arranged on opposite sides of the fore and aft centre line.
7. A support as claimed in claim 6, in which the relatively rearwardly located single leg is mounted on the fore and aft centre line of the support when view in plan, the pair of legs constituting the relatively forwardly located set of legs being arranged on opposite sides of the fore and aft centre line.
8. A support as claimed in claim 1, in which the roof canopy unit is provided with a forwardly extendable beam capable of being extended from the front of the roof canopy towards the working face.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB79/32252 | 1979-09-18 | ||
| GB7932252 | 1979-09-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129661A true CA1129661A (en) | 1982-08-17 |
Family
ID=10507895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA360,230A Expired CA1129661A (en) | 1979-09-18 | 1980-09-15 | Underground mining roof support systems and supports for use with such systems |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1129661A (en) |
| DE (1) | DE3035073A1 (en) |
-
1980
- 1980-09-15 CA CA360,230A patent/CA1129661A/en not_active Expired
- 1980-09-17 DE DE19803035073 patent/DE3035073A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE3035073A1 (en) | 1981-04-02 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |