CA1108420A - Mine roof supports - Google Patents
Mine roof supportsInfo
- Publication number
- CA1108420A CA1108420A CA340,822A CA340822A CA1108420A CA 1108420 A CA1108420 A CA 1108420A CA 340822 A CA340822 A CA 340822A CA 1108420 A CA1108420 A CA 1108420A
- Authority
- CA
- Canada
- Prior art keywords
- shield
- support
- roof beam
- roof
- rams
- 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
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH 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
- E21D23/0034—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 comprising a goaf shield articulated to a base member
- E21D23/0043—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 comprising a goaf shield articulated to a base member and supported by two or more rows of struts parallel to the working face
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH 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
- E21D23/04—Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of props; Means for counteracting lateral sliding on inclined floor
Abstract
ABSTRACT OF THE DISCLOSURE
A mine roof support comprises a plurality of hydraulically extensible chock legs 5,6, articulated at upper ends thereof to one or more roof beams 3 and at lower ends thereof to one or more base members 1, a shield 9 pivotally connected to a rearward part of the base member 1 and also pivotally connected to a rearward part of the roof beam 3, with permanently pressurised rams 12 both located between a pair of laterally spaced chock legs 6 and one located to each side of the centre line 19 of the support, the rams being mutually inclined with respect to the centre line 19 and reacting via the shield 9 on the roof beam 3, and a pair of tie bars 11 located one at or towards each side of the support and both connected between the roof beam 3 and the shield 9.
A mine roof support comprises a plurality of hydraulically extensible chock legs 5,6, articulated at upper ends thereof to one or more roof beams 3 and at lower ends thereof to one or more base members 1, a shield 9 pivotally connected to a rearward part of the base member 1 and also pivotally connected to a rearward part of the roof beam 3, with permanently pressurised rams 12 both located between a pair of laterally spaced chock legs 6 and one located to each side of the centre line 19 of the support, the rams being mutually inclined with respect to the centre line 19 and reacting via the shield 9 on the roof beam 3, and a pair of tie bars 11 located one at or towards each side of the support and both connected between the roof beam 3 and the shield 9.
Description
Z ~
This invention relates to a mine roof support of the type of support incorporating a plurality of hydraulically extensible chock legs articulated at upper ends thereof to one or more roof bars 9 and at lower ends thereof to one or more base members.
Such supports are commonly used in :
the longwall mining o~ minerals/ notably coal, : by being spaced along a mineral face, wi~.h an I
armoured cnnveyor interposed between ~he supports .
and the f ace, the supports being connected to the conveyor to advance the individual pans thereof towards the newly exposed mineral face~ ~ .
after passage of the mineral winning device, with the support~ in their roof supp~rting conditlon. Con~ersely, when it lS required to advance the supports towards the advanced c~nveyor, the ~ chock legs are retracted and the supports ~ pulled forwar~ by reacting on the conveyor.
;: 20 In pract.ice, however, there is relative .
movement between the mine roof and the mine floor, while there also exists the possibility : of the roof beam(s) striking a roof projection~
whilst the support is being advanced~ -Both - 25 these effects result in the upper ends of the , ,, ~ - , :, :
, , chock legs ~eing displaced. The displacement is usually rear~ardly or a combination of rearward and lateral displacement, but forward displacement ls not unknown in certain conditions.
To avoid damage to the choc~ legs by this displacement9 several proposals have been put forward aimed not only at accommodating a few degrees of displacemellt, but also serving to restore the chock legs to a pre-determined position, upon release of the support from the roof~ However, such restoration proposals have all incorporated a restoration device reacting between the base member(s) of the support and at least one chock leg thereof. This of necessity results in the introduction of bending loads and stresses into the chock Ieg(s).
In our U.K. Application~l74~2/77 (= U.S. Patent 4139326) is described a mine roof support wherein the transmission of restoration forces via ~he chock legs i~ avoided, the invention employing permanently loaded force supplying means operable through a shield of ths support. If only linear displ~cement forces (i.e. those operable along the centre line of the roof support~ were encountered in ,.....
. ' ' practice then the location of force applying means, e.g. rams, with lines of action parallel to the centre line would be satisfactory. However, non-linear Eorces are commonly encountered and a proposal described in our U.K. Application 17442/77 (=U.S. Patent 4139326) to deal with this is to employ two spaced apart rams located on opposite sides of the centre line of the support and inclined with respect to such centre line. For optimum effectiveness, it is desirable for these rams to be spaced as far apart as possible, i.eO one adjacent each lateral side of the support which implies, ina four leg support, that the rams are outside the legs. ~owever, in certain circumstances, it is not possible to locate the rams in this optimum position and accordingly they must be located between the legs, thereby reducing their effectiveness in firstly resisting displacemnt forces and secondly in restoring a displaced roof bar(s?, and it 1s to this form of roof support that the present invention is directed.
According to the present invention, there is provided a mine roof support comprising at least one roof beam and at least one base member, a plurality of hydraulically extensible chock legs articulated at upper ends thereof to said roof beam and at lower ends to said base member, a shield pivotally connected to a rearward part of said base member and also pivotally connected to a rearward part of said roof beam, permanently pressurised rams, both located between a pair of said chock legs which are laterally spaced and one located to each side of the centre line of said support, said rams being mutually inclined with respect t~ .
to said cen-tre line and reacting via said shield on said roof beam in such a manner that said rams resist displacement of said roof beam and, upon retraction of said chock legs from a mine roof, restore displaced chock legs to a predetermined position, and a pair of tie bars located one towards each side of said support and both co].mected between said roof beam and said shield, said tie bars readily allowing mutual convergence of said roof beam and said shield, and also determining the length of effectiveness of said rams and hence maximum allowable separation between said roof beam and said shield at each side of said support.
Thus, with the support according to the present invention, the tie bars ensure the presence of greater turning moments to resist .,i,,.^
lateral or twisting forces on the roof beam(s) and subsequently to restore the roof beam~-s) to a predetermined location at the last increment of restoration, such as when a first ram is nearly extended and the second is not so extended. Thus the second ram employs the fulcrum provided by the tie bar remote Erom that ram.
Preferably, the shield is pivotally connected via a link mechanism to the base member~ The link mechanism may comprise two links, one above the other, and preferably located at each side of the support within the overall width of the support.
Each tie bar may be constituted by a bolt9 the bolt head being located in a slot, e.g. provided in a bracket carried by the shiel~, while the threaded bolt stem may pass through an aperturP in a bracket carried by the roQf 1-bar, with a nut applied to the threaded bolt stem. The use of washers at the threaded end enables the effective lengths of the bolts ~o be readily adjusted to predetermine the leg angle, The rams are preferably suspended from ~he roof beam(s) and react on an upper portion of the shield. In detail, the piston rod of .,...~ -qæ~
each ram may be pivotally attached to the roof beam e.g. via a pin carried by a bracket attached to the roof beam, while the cylinder of eaeh ram may be similarly attached to the shield.
Conveniently, the rams are provided with a check valve for admission of fluid and with a relief valve to yield when a predetermined pressure is attained. Preferably, in an initial, predetermined and non-displaced condition, the piston rod of each ram is fully extended so that should rearward roof beam displacement for instance occurl the cylinder of each ram remains stationary while the piston of each ram sli ~ into its cylinder, the annulus volume being enlarged. The maximum allowable chock leg inclination occurs when the rams have been fully retracted. When the roof support is released~ i either fully or partially from the roof, re-admission of pressure fluid to the full bore sides of the rams, to replace that exhausted during roof beam displacement9 causes the rams to react on the shield to restore the roof beam[ s) to the predete~mined position. Such readmission may be automatically effected by permanently ,,~ .
.
. .
. . , . :
- '. ' , ' " "' :
~$~
connecting the full hore sides of the rams to th~ hydraul ic mains supplying the chock legs, while the tie bars increase the effective-ness of the rams towards the end of their restoration movements.
Preferably, the two rams are so inclined that their forward ends are adjacent one another and their rearward ends are remote from one another, This enables latera~
displacement to be countered and/or restored.
One may readily reverse the mode of operation of the restoration rams if forward roof movement is encountered, by permanently pressurising the annulus side of the rams.
Thus for univeral use, the rams may be made double-aeting.
The shield may be generally channel shaped, adapted, in the retracted condition of the roof support, to t21escope over a built up ~o rear base portion of the support which portion becomes increasingly exposed as the shield is lifted until the roof beam(s~ engages the mine roof.
The invention will now be ~urther descri~ed by way of example, with reference to the accompanying d~awings, in whichs-. ~ . . ' '.
.,.,. . . ~ . .
, ' ' ..
- . , . ., . : ~
Figure 1 is a side elevation of a four leg, hydraulically powered, self-advancing mine roof support in accordance with the invention;
Figure 2 is a view in the direction of arrow A of Figure 1 on the underside of the roof beam;
Figure 3 is an enlarged view, partly in section, o~ a tie bar of Figures 1 and 2;
and Figure 4 is an enlarged view of a ram of Figures 1 and 2.
In Figure 1, the mine roof support can be seen to comprise a base member 1 seated on a mine floor 2 with a roof beam 3 in engagement ; ~ith a mine roof 4, the base member 1 and roof ; beam 3 being spaced apart by two forwardly located, hydraulically exter~sible chock legs 5 and two similar rearwardly located chock legs 6, Each chock leg is articulated to both the base member 1 and the roof beam 3 at known joints incorporating arcuate bearing surfaces ~ and 8. A shield 9 is pivotally connected to a rearward part of the base member 1 by being ~ounted at each side on pairs of upper and .
. :. ~ , , : ~:, :. .
This invention relates to a mine roof support of the type of support incorporating a plurality of hydraulically extensible chock legs articulated at upper ends thereof to one or more roof bars 9 and at lower ends thereof to one or more base members.
Such supports are commonly used in :
the longwall mining o~ minerals/ notably coal, : by being spaced along a mineral face, wi~.h an I
armoured cnnveyor interposed between ~he supports .
and the f ace, the supports being connected to the conveyor to advance the individual pans thereof towards the newly exposed mineral face~ ~ .
after passage of the mineral winning device, with the support~ in their roof supp~rting conditlon. Con~ersely, when it lS required to advance the supports towards the advanced c~nveyor, the ~ chock legs are retracted and the supports ~ pulled forwar~ by reacting on the conveyor.
;: 20 In pract.ice, however, there is relative .
movement between the mine roof and the mine floor, while there also exists the possibility : of the roof beam(s) striking a roof projection~
whilst the support is being advanced~ -Both - 25 these effects result in the upper ends of the , ,, ~ - , :, :
, , chock legs ~eing displaced. The displacement is usually rear~ardly or a combination of rearward and lateral displacement, but forward displacement ls not unknown in certain conditions.
To avoid damage to the choc~ legs by this displacement9 several proposals have been put forward aimed not only at accommodating a few degrees of displacemellt, but also serving to restore the chock legs to a pre-determined position, upon release of the support from the roof~ However, such restoration proposals have all incorporated a restoration device reacting between the base member(s) of the support and at least one chock leg thereof. This of necessity results in the introduction of bending loads and stresses into the chock Ieg(s).
In our U.K. Application~l74~2/77 (= U.S. Patent 4139326) is described a mine roof support wherein the transmission of restoration forces via ~he chock legs i~ avoided, the invention employing permanently loaded force supplying means operable through a shield of ths support. If only linear displ~cement forces (i.e. those operable along the centre line of the roof support~ were encountered in ,.....
. ' ' practice then the location of force applying means, e.g. rams, with lines of action parallel to the centre line would be satisfactory. However, non-linear Eorces are commonly encountered and a proposal described in our U.K. Application 17442/77 (=U.S. Patent 4139326) to deal with this is to employ two spaced apart rams located on opposite sides of the centre line of the support and inclined with respect to such centre line. For optimum effectiveness, it is desirable for these rams to be spaced as far apart as possible, i.eO one adjacent each lateral side of the support which implies, ina four leg support, that the rams are outside the legs. ~owever, in certain circumstances, it is not possible to locate the rams in this optimum position and accordingly they must be located between the legs, thereby reducing their effectiveness in firstly resisting displacemnt forces and secondly in restoring a displaced roof bar(s?, and it 1s to this form of roof support that the present invention is directed.
According to the present invention, there is provided a mine roof support comprising at least one roof beam and at least one base member, a plurality of hydraulically extensible chock legs articulated at upper ends thereof to said roof beam and at lower ends to said base member, a shield pivotally connected to a rearward part of said base member and also pivotally connected to a rearward part of said roof beam, permanently pressurised rams, both located between a pair of said chock legs which are laterally spaced and one located to each side of the centre line of said support, said rams being mutually inclined with respect t~ .
to said cen-tre line and reacting via said shield on said roof beam in such a manner that said rams resist displacement of said roof beam and, upon retraction of said chock legs from a mine roof, restore displaced chock legs to a predetermined position, and a pair of tie bars located one towards each side of said support and both co].mected between said roof beam and said shield, said tie bars readily allowing mutual convergence of said roof beam and said shield, and also determining the length of effectiveness of said rams and hence maximum allowable separation between said roof beam and said shield at each side of said support.
Thus, with the support according to the present invention, the tie bars ensure the presence of greater turning moments to resist .,i,,.^
lateral or twisting forces on the roof beam(s) and subsequently to restore the roof beam~-s) to a predetermined location at the last increment of restoration, such as when a first ram is nearly extended and the second is not so extended. Thus the second ram employs the fulcrum provided by the tie bar remote Erom that ram.
Preferably, the shield is pivotally connected via a link mechanism to the base member~ The link mechanism may comprise two links, one above the other, and preferably located at each side of the support within the overall width of the support.
Each tie bar may be constituted by a bolt9 the bolt head being located in a slot, e.g. provided in a bracket carried by the shiel~, while the threaded bolt stem may pass through an aperturP in a bracket carried by the roQf 1-bar, with a nut applied to the threaded bolt stem. The use of washers at the threaded end enables the effective lengths of the bolts ~o be readily adjusted to predetermine the leg angle, The rams are preferably suspended from ~he roof beam(s) and react on an upper portion of the shield. In detail, the piston rod of .,...~ -qæ~
each ram may be pivotally attached to the roof beam e.g. via a pin carried by a bracket attached to the roof beam, while the cylinder of eaeh ram may be similarly attached to the shield.
Conveniently, the rams are provided with a check valve for admission of fluid and with a relief valve to yield when a predetermined pressure is attained. Preferably, in an initial, predetermined and non-displaced condition, the piston rod of each ram is fully extended so that should rearward roof beam displacement for instance occurl the cylinder of each ram remains stationary while the piston of each ram sli ~ into its cylinder, the annulus volume being enlarged. The maximum allowable chock leg inclination occurs when the rams have been fully retracted. When the roof support is released~ i either fully or partially from the roof, re-admission of pressure fluid to the full bore sides of the rams, to replace that exhausted during roof beam displacement9 causes the rams to react on the shield to restore the roof beam[ s) to the predete~mined position. Such readmission may be automatically effected by permanently ,,~ .
.
. .
. . , . :
- '. ' , ' " "' :
~$~
connecting the full hore sides of the rams to th~ hydraul ic mains supplying the chock legs, while the tie bars increase the effective-ness of the rams towards the end of their restoration movements.
Preferably, the two rams are so inclined that their forward ends are adjacent one another and their rearward ends are remote from one another, This enables latera~
displacement to be countered and/or restored.
One may readily reverse the mode of operation of the restoration rams if forward roof movement is encountered, by permanently pressurising the annulus side of the rams.
Thus for univeral use, the rams may be made double-aeting.
The shield may be generally channel shaped, adapted, in the retracted condition of the roof support, to t21escope over a built up ~o rear base portion of the support which portion becomes increasingly exposed as the shield is lifted until the roof beam(s~ engages the mine roof.
The invention will now be ~urther descri~ed by way of example, with reference to the accompanying d~awings, in whichs-. ~ . . ' '.
.,.,. . . ~ . .
, ' ' ..
- . , . ., . : ~
Figure 1 is a side elevation of a four leg, hydraulically powered, self-advancing mine roof support in accordance with the invention;
Figure 2 is a view in the direction of arrow A of Figure 1 on the underside of the roof beam;
Figure 3 is an enlarged view, partly in section, o~ a tie bar of Figures 1 and 2;
and Figure 4 is an enlarged view of a ram of Figures 1 and 2.
In Figure 1, the mine roof support can be seen to comprise a base member 1 seated on a mine floor 2 with a roof beam 3 in engagement ; ~ith a mine roof 4, the base member 1 and roof ; beam 3 being spaced apart by two forwardly located, hydraulically exter~sible chock legs 5 and two similar rearwardly located chock legs 6, Each chock leg is articulated to both the base member 1 and the roof beam 3 at known joints incorporating arcuate bearing surfaces ~ and 8. A shield 9 is pivotally connected to a rearward part of the base member 1 by being ~ounted at each side on pairs of upper and .
. :. ~ , , : ~:, :. .
2~
l~wer links 10, while the shield is also pi~otally attached to a rearward part of the roof beam 3, by means of tie bars ll and permanently pressurised rams 12.
Each ram 12 comprises a piston rod 13 pivotally secured at 14 to a bracket 15 depending from the underside of the roof beam 3, while the full bore cavity of a cylinder 16 is permanently pressurised with hydraulic fluid so that p.iston 13 is normally urged to the extended position shownJ the cylinder 16 being pivotally attached to a bracket 17 of the shield 9. As shown in Figure 2, each ram 12 is located along an axis 18 inclined with respect to the centre line 19 of the roof suppor~. .
Each tie bar 11 comprises a bolt 20 . having at one end a bolt head 21 located in a slot 22 cf a tube 23 pivotally attached at 24 to a bracket 25 of the shield 9. At its other en~ the ~olt 20 terminates in a threaded stem passing through an aperture 26 in a bracket 27 carried by the roof bar 3, a nut 28 being applied to the threaded stem to secure that bolt end to the bracket 27.
In the drawings, the roof support ' ~ .
.
- . : ~ - . .. . . .
, - .: . : ..
' : . , , , . ' ,. : ' :
, ,, ' ', ' . ' .' ~
- ~o -i5 shown in a non-displaced condition. If and when rearward displacement of tne upper end of the chock legs 5, 6 occurs e.g. by natural rearward movement of the roof 4, or during advance of the roof support towards a mineral face, the cylinders 16 remain stationary, or substantially so, due to the non-movement of the shield 9 ~ while the piston rods 13, being carried by the roof beam 3, are displaced ~0 into the respective cylinders 16.
l~wer links 10, while the shield is also pi~otally attached to a rearward part of the roof beam 3, by means of tie bars ll and permanently pressurised rams 12.
Each ram 12 comprises a piston rod 13 pivotally secured at 14 to a bracket 15 depending from the underside of the roof beam 3, while the full bore cavity of a cylinder 16 is permanently pressurised with hydraulic fluid so that p.iston 13 is normally urged to the extended position shownJ the cylinder 16 being pivotally attached to a bracket 17 of the shield 9. As shown in Figure 2, each ram 12 is located along an axis 18 inclined with respect to the centre line 19 of the roof suppor~. .
Each tie bar 11 comprises a bolt 20 . having at one end a bolt head 21 located in a slot 22 cf a tube 23 pivotally attached at 24 to a bracket 25 of the shield 9. At its other en~ the ~olt 20 terminates in a threaded stem passing through an aperture 26 in a bracket 27 carried by the roof bar 3, a nut 28 being applied to the threaded stem to secure that bolt end to the bracket 27.
In the drawings, the roof support ' ~ .
.
- . : ~ - . .. . . .
, - .: . : ..
' : . , , , . ' ,. : ' :
, ,, ' ', ' . ' .' ~
- ~o -i5 shown in a non-displaced condition. If and when rearward displacement of tne upper end of the chock legs 5, 6 occurs e.g. by natural rearward movement of the roof 4, or during advance of the roof support towards a mineral face, the cylinders 16 remain stationary, or substantially so, due to the non-movement of the shield 9 ~ while the piston rods 13, being carried by the roof beam 3, are displaced ~0 into the respective cylinders 16.
Claims (7)
1. A mine roof support comprising at least one roof beam and at least one base member, a plurality of hydraulically extensible chock legs articulated at upper ends thereof to said roof beam and at lower ends to said base member, a shield pivotally connected to a rearward part of said base member and also pivotally connected to a rearward part of said roof beam, permanently pressurised rams, both located between a pair of said chock legs which are laterally spaced and one located to each side of the centre line of said support, said rams being mutually inclined with respect to said centre line and reacting via said shield on said roof beam in such a manner that said rams resist displacement of said roof beam and, upon retraction of said chock legs from a mine roof, restore displaced chock legs to a predetermined position, and a pair of tie bars located one towards each side of said support and both connected between said roof beam and said shield, said tie bars readily allowing mutual convergence of said roof beam and said shield, and also determining the length of effectiveness of said rams and hence maximum allowable separation between said roof beam and said shield at each side of said support.
2. A mine roof support as claimed in claim 1, wherein said shield is pivotally connected via a link mechanism to said base member.
3. A mine roof support as claimed in claim 2, wherein said link mechanism comprises two links, one above the other.
4. A mine roof support as claimed in claim 1, wherein said tie bars are each constituted by a bolt, a head of said bolt being located in a slot while a threaded stem of said bolt passes through an aperture in a bracket carried by said roof beam, with a nut applied to said threaded bolt stem.
5. A mine roof support as claimed in claim 4, wherein said slot is provided in a bracket carried by said shield.
6. A mine roof support as claimed in claim 1, wherein said rams are suspended from said roof beam and react on an upper portion of said shield.
7. A mine roof support as claimed in claim 1, wherein said two rams are mutually inclined so that their forward ends are adjacent one another and their rearward ends are remote from one another.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7846370 | 1978-11-28 | ||
| GB7846370 | 1978-11-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1108420A true CA1108420A (en) | 1981-09-08 |
Family
ID=10501370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA340,822A Expired CA1108420A (en) | 1978-11-28 | 1979-11-28 | Mine roof supports |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU529191B2 (en) |
| CA (1) | CA1108420A (en) |
| DE (1) | DE2947654A1 (en) |
| IN (1) | IN151643B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114233358A (en) * | 2021-12-29 | 2022-03-25 | 安阳永安贺驼煤矿有限公司 | Bag type filling support device for top of stoping roadway |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2850073A1 (en) * | 1978-11-18 | 1980-05-29 | Fletcher Sutcliffe Wild Ltd | Roof support for longwall mining - has permanently loaded force applicator acting on roof beams and restoring displaced chock legs after predetermined pressure drop |
-
1979
- 1979-11-26 IN IN1237/CAL/79A patent/IN151643B/en unknown
- 1979-11-27 AU AU53202/79A patent/AU529191B2/en not_active Ceased
- 1979-11-27 DE DE19792947654 patent/DE2947654A1/en active Granted
- 1979-11-28 CA CA340,822A patent/CA1108420A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114233358A (en) * | 2021-12-29 | 2022-03-25 | 安阳永安贺驼煤矿有限公司 | Bag type filling support device for top of stoping roadway |
| CN114233358B (en) * | 2021-12-29 | 2024-04-12 | 安阳永安贺驼煤矿有限公司 | Bag-type filling support device for top of stope |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2947654C2 (en) | 1988-03-17 |
| IN151643B (en) | 1983-06-18 |
| DE2947654A1 (en) | 1980-06-04 |
| AU5320279A (en) | 1980-05-29 |
| AU529191B2 (en) | 1983-05-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |