U.S. patent application number 10/701721 was filed with the patent office on 2004-05-20 for provision of support in underground mine workings.
This patent application is currently assigned to NAMPAK PRODUCTS LIMITED. Invention is credited to Van Zyl, Rory Joseph.
Application Number | 20040096278 10/701721 |
Document ID | / |
Family ID | 32298893 |
Filed Date | 2004-05-20 |
United States Patent
Application |
20040096278 |
Kind Code |
A1 |
Van Zyl, Rory Joseph |
May 20, 2004 |
Provision of support in underground mine workings
Abstract
The invention provides a bag for spacing apart walls in an
underground mine working, and including opposed load-bearing walls
of flexible sheet material, each defining a substantially centrally
located opening and an open-ended radial slot extending between and
intersecting the central opening and outer periphery of the
load-bearing wall, the openings and slots of the load-bearing walls
being in register. There is an intermediate wall of flexible sheet
material extending between the load-bearing walls and connected
thereto substantially along the entire periphery of each
load-bearing wall. A charging connector through the wall is for
connection to a source of flowable substance under pressure for
charging the bag therewith, to expand the bag by displacing the
load-bearing walls away from each other. The invention also
provides an installation and method which employ the bag to space
the walls apart.
Inventors: |
Van Zyl, Rory Joseph;
(Durban, ZA) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
NAMPAK PRODUCTS LIMITED
|
Family ID: |
32298893 |
Appl. No.: |
10/701721 |
Filed: |
November 5, 2003 |
Current U.S.
Class: |
405/289 ;
248/354.1; 299/31; 405/288; 405/300 |
Current CPC
Class: |
E21D 15/483 20130101;
E02D 35/00 20130101 |
Class at
Publication: |
405/289 ;
405/288; 405/300; 248/354.1; 299/031 |
International
Class: |
E21C 029/00; E02D
003/02; A47F 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2002 |
ZA |
2002/9318 |
Claims
1. A bag for use in spacing apart a pair of opposed walls in an
underground mine working, which bag includes: a pair of opposed
load-bearing walls of flexible sheet material, each load-bearing
wall defining a substantially centrally located opening and an
open-ended radial slot which extends between and intersects both
the central opening and the outer periphery of the load-bearing
wall, the openings and the slots of the load-bearing walls being in
register; an intermediate wall of flexible sheet material, the
intermediate wall extending between the load-bearing walls and
being connected to each load-bearing wall substantially along the
entire periphery of each load-bearing wall; and a charging
connector through a wall of the bag, for connection to a source of
flowable substance under pressure for charging the interior of the
bag therewith, to expand the bag by displacing the load-bearing
walls away from each other, to provide an expanded bag having a
centrally located passage extending therethrough from one
load-bearing wall to the other, and an open-ended space
intersecting and extending between the centrally located passage
and the outer periphery of the bag.
2. A bag as claimed in claim 1, in which the intermediate wall has
a width, in a direction from one said load bearing wall to the
other, which is constant and has a value of 5-200 cm.
3. A bag as claimed in claim 1, which includes a restraining
arrangement for restraining the bag to inhibit widening of the
slots by movement of opposite sides of the slots away from each
other in response to expansion of the bag.
4. A bag as claimed in claim 3, in which the restraining
arrangement comprises at least one pair of ties, the ties of each
pair being anchored to the intermediate wall at respective
positions selected so that the ties of the pair can be tied
together to inhibit said widening of the slots.
5. A bag as claimed in claim 4, in which the bag is provided with a
plurality of pairs of ties, the pairs being spaced in series and
the series extending, in a direction across the width of the
intermediate wall, from one said load-bearing wall to the
other.
6. A bag as claimed in claim 1, in which the bag is porous, being
at least partially impervious to the solids in a cementitious
slurry and being pervious to the water in such slurry.
7. A bag as claimed in claim 1, in which the bag is impervious to
both said solids and to water.
8. A bag as claimed in claim 7, which comprises a porous outer
layer and a water-impervious bladder which lines the outer layer
and is located inside the outer layer, the charging connector being
a non-return inlet valve and leading from the exterior of the outer
layer into the interior of the bladder.
9. A bag as claimed in claim 1, in which the bag is of a woven
polymeric plastics material.
10. A bag as claimed in claim 9, in which the intermediate wall is
connected to the load-bearing walls by stitching.
11. An installation spacing apart a pair of opposed walls in an
underground mine working, which installation includes: an elongated
strut extending between said opposed walls of the underground mine
working, with ends of the strut respectively abutting said opposed
walls of the underground mine working and with the strut under
compression; and a plurality of bags, each bag including a pair of
opposed load-bearing walls of flexible sheet material, each
load-bearing wall defining a substantially centrally located
opening and an open-ended radial slot which extends between and
intersects both the central opening and the outer periphery of the
load-bearing wall, the openings and the slots of the load-bearing
walls being in register, an intermediate wall of flexible sheet
material, the intermediate wall extending between the load-bearing
walls and being connected to each load-bearing wall substantially
along the entire periphery of each load-bearing wall, and a
charging connector through a wall of the bag, for connection to a
source of flowable substance under pressure for charging the
interior of the bag therewith, to expand the bag by displacing the
load-bearing walls away from each other, to provide an expanded bag
having a centrally located passage extending therethrough from one
load-bearing wall to the other, and an open-ended space
intersecting and extending between the centrally located passage
and the outer periphery of the bag, the bags received on the strut,
the bags being arranged face-to-face in series with one another
with the load-bearing walls of adjacent bags in abutment, the
series extending along the strut from one said wall of the
underground mine working to the opposed wall of the underground
mine working, each bag containing a solid substance under
compression whereby the bag is at least partly expanded, and the
strut passing through the centrally located openings of the
load-bearing walls of each bag.
12. An installation as claimed in claim 11, in which the opposed
walls of the underground mine working are a foot wall and a hanging
wall of a stope forming part of the underground mine working, the
strut and the series of bags extending upwardly from the foot wall
to the hanging wall and supporting the hanging wall above the foot
wall.
13. An installation as claimed in claim 11, in which the opposed
walls of the underground mine working are a pair of opposed side
walls of a stope, the strut and series of bags extending more or
less horizontally between said side walls.
14. An installation as claimed in claim 11, in which each bag
comprises an annulus which is interrupted by a radially extending
space, opposed parts of the intermediate wall of the bag, at the
radially outer end of the space, being fastened together to inhibit
widening of the space in response to expansion of the bag.
15. An installation as claimed in claim 11, in which the bags are
received on the strut in an arrangement such that the spaces of
successive bags are angularly offset relative to each other so that
said spaces are out of register with each other when viewed
lengthwise relative to the series.
16. A method of spacing apart a pair of opposed walls in an
underground mine working in which a strut is held captive and under
compression by abutment of ends of the strut respectively against a
pair of opposed walls forming part of the underground mine working,
the strut extending between said walls, the method including the
steps of: positioning a plurality of bags in series on the strut,
each bag including a pair of opposed load-bearing walls of flexible
sheet material, each load-bearing wall defining a substantially
centrally located opening and an open-ended radial slot which
extends between and intersects both the central opening and the
outer periphery of the load-bearing wall, the openings and the
slots of the load-bearing walls being in register, an intermediate
wall of flexible sheet material, the intermediate wall extending
between the load-bearing walls and being connected to each
load-bearing wall substantially along the entire periphery of each
load-bearing wall, and a charging connector through a wall of the
bag, for connection to a source of flowable substance under
pressure for charging the interior of the bag therewith, to expand
the bag by displacing the load-bearing walls away from each other,
to provide an expanded bag having a centrally located passage
extending therethrough from one load-bearing wall to the other, and
an open-ended space intersecting and extending between the
centrally located passage and the outer periphery of the bag, the
positioning of the bags on the strut being so that the strut is
received in the centrally located openings of the load-bearing
walls of each bag; and at least partially expanding each bag by
means of a flowable substance under pressure to place each bag
under compression and to cause it to assume an expanded shape.
17. A method as claimed in claim 16, which includes the step, prior
to the expanding, of fastening together opposed parts of the
intermediate wall at or adjacent the outer periphery of the bag, to
restrain and inhibit moving apart of said opposed parts in response
to the expanding of the bag.
18. A method as claimed in claim 16, which includes the step of
positioning the strut between a foot wall and a hanging wall in a
stope forming part of the underground mine working, so that the
strut extends upwardly from the foot wall to the hanging wall of
the stope, and so that the bags form a stacked series which extends
upwardly from the foot wall to the hanging wall.
19. A method as claimed in claim 16, in which the step of
positioning the bags is such that they are arranged with the spaces
of successive bags angularly offset relative to each other so that
said spaces are out of register with each other when viewed
lengthwise relative to the series.
Description
[0001] THIS INVENTION relates to the spacing apart of walls in an
underground mine working. In particular, it relates to a bag for
use in spacing apart a pair of opposed walls in an underground mine
working, for example, a hanging wall and a foot wall of a stope
forming part of the underground mine working; to an installation
spacing apart a pair of opposed walls in an underground mine
working; and to a method of spacing apart walls in an underground
mine working.
[0002] The invention provides a bag for use in spacing apart a pair
of opposed walls in an underground mine working, which bag
includes:
[0003] a pair of opposed load-bearing walls of flexible sheet
material, each load-bearing wall defining a substantially centrally
located opening and an open-ended radial slot which extends between
and intersects both the central opening and the outer periphery of
the load-bearing wall, the openings and the slots of the
load-bearing walls being in register;
[0004] an intermediate wall of flexible sheet material, the
intermediate wall extending between the load-bearing walls and
being connected to each load-bearing wall substantially along the
entire periphery of each load-bearing wall; and
[0005] a charging connector through a wall of the bag, for
connection to a source of flowable substance under pressure for
charging the interior of the bag therewith, to expand the bag by
displacing the load-bearing walls away from each other, to provide
an expanded bag having a centrally located passage extending
therethrough from one load-bearing wall to the other, and an
open-ended space intersecting and extending between the centrally
located passage and the outer periphery of the bag.
[0006] By the entire periphery of each load-bearing wall is meant
not only the outer periphery of the load-bearing wall, but also its
inner periphery along the edge of its opening and its periphery
along the edges of its slot.
[0007] Differently defined, the invention provides, in a bag for
use in spacing apart a pair of opposed walls in an underground mine
working, the bag being of the type having walls of flexible sheet
material and having a charging connector for connection to a source
of flowable substance under pressure to dilate the bag, the
improvement whereby the walls of the bag comprise:
[0008] a pair of opposed load-bearing walls, each load-bearing wall
having a substantially centrally located opening and an open-ended
slot which intersects, and extends radially between, the centrally
located opening and the outer periphery of the load-bearing wall,
the openings and slots of the load-bearing walls being in register;
and
[0009] an intermediate wall which extends between the load-bearing
walls and is connected to each load-bearing wall substantially
along the entire periphery of each load-bearing wall, so that, upon
expansion of the bag by charging of the bag through the charging
connector with a flowable substance, the peripheries of the
load-bearing walls are displaced away from each other.
[0010] The expanded bag will thus, when one of the load-bearing
walls is viewed face-on, have a substantially centrally located
passage extending through the bag from one load-bearing wall to the
other, and an open-ended space intersecting and extending between
the centrally located passage and the outer periphery of the
bag.
[0011] The intermediate wall may have a width, in a direction from
one said load bearing wall to the other, which is constant and has
a value of 5-200 cm, preferably 15-30 cm.
[0012] In particular, the bag may include a restraining arrangement
for restraining the bag to inhibit widening of the slots by
movement of opposite sides of the slots away from each other in
response to expansion of the bag. In one embodiment of the
invention, for example, the restraining arrangement includes a
fastening mechanism for fastening together portions of the
intermediate wall separated by the open-ended space.
[0013] More particularly, the restraining arrangement may comprise
at least one pair of ties, the ties of each pair being anchored to
the intermediate wall at respective positions selected so that the
ties of the pair can be tied together to inhibit said widening of
the slots. In a particular embodiment of the invention, the bag is
provided with a plurality of pairs of ties, the pairs being spaced
in series and the series extending, in a direction across the width
of the intermediate wall, from one said load-bearing wall to the
other.
[0014] The flowable substance may be any suitable flowable
substance selected from those known in the art, and such flowable
substances include water an flowable grouts or slurries, in
particular flowable cementitious grouts or slurries, in which
cementitious solids are slurried with water.
[0015] The bag may be porous, being at least partially impervious
to the solids in a cementitious slurry and being pervious to the
water in such slurry, thus being a so-called weeping bag; or the
bag may instead be impervious to both said solids and to water, so
that the bag is not a weeping bag.
[0016] In the latter case, the bag may comprise a porous outer
layer and a water-impervious bladder which lines the outer layer
and is located inside the outer layer, the charging connector being
a non-return inlet valve leading from the exterior of the outer
layer into the interior of the bladder.
[0017] When the bag is porous or has a porous outer layer, the bag
or layer may be of a woven polymeric plastics material, for
instance being woven propylene, the porous intermediate wall being
connected to the porous load-bearing walls by stitching.
[0018] The invention extends to an installation spacing apart a
pair of opposed walls of an underground mine working, which
installation includes:
[0019] an elongated strut extending between said opposed walls of
the underground mine working, with ends of the strut respectively
abutting said opposed walls of the underground mine working and
with the strut under compression; and
[0020] a plurality of bags as claimed in claim 1, received on the
strut, the bags being arranged face-to-face in series with one
another with the load-bearing walls of adjacent bags in abutment,
the series extending along the strut from one said wall of the
underground mine working to the opposed wall of the underground
mine working, each bag containing a solid substance under
compression whereby the bag is at least partly expanded, and the
strut passing through the centrally located openings of the
load-bearing walls of each bag.
[0021] The opposed walls of the underground mine working may be a
foot wall and a hanging wall of a stope forming part of the
underground mine working, the strut and the series of bags
extending upwardly from the foot wall to the hanging wall and
supporting the hanging wall above the foot wall.
[0022] Instead, the opposed walls of the underground mine working
may be a pair of opposed side walls of a stope, the strut and
series of bags extending more or less horizontally between said
side walls.
[0023] In particular, each bag may comprise an annulus which is
interrupted by a radially extending space, opposed parts of the
intermediate wall of the bag, at the radially outer end of the
space, being fastened together to inhibit widening of the space in
response to expansion of the bag.
[0024] The bags may be received on the strut in an arrangement such
that the spaces of successive bags are angularly offset relative to
each other so that said spaces are out of register with each other
when viewed lengthwise relative to the series.
[0025] The invention further provides a method of spacing apart
walls in an underground mine working in which a strut is held
captive and under compression by abutment of ends of the strut
respectively against a pair of opposed walls forming part of the
underground mine working, the strut extending between said walls,
the method including the steps of:
[0026] positioning a plurality of bags as claimed in claim 1, in
series on the strut so that the strut is received in the centrally
located openings of the load-bearing walls of each bag; and
[0027] at least partially expanding each bag by means of a flowable
substance under pressure to place each bag under compression and to
cause it to assume an expanded shape.
[0028] The method may include the step, prior to the expanding, of
fastening together opposed parts of the intermediate wall at or
adjacent the outer periphery of the bag, to restrain and inhibit
moving apart of said opposed parts in response to the expanding of
the bag.
[0029] The method may include the step of positioning the strut
between a foot wall and a hanging wall in a stope forming part of
the underground mine working, so that the strut extends upwardly
from the foot wall to the hanging wall of the stope, and so that
the bags form a stacked series which extends upwardly from the foot
wall to the hanging wall.
[0030] In particular, the step of positioning the bags may be such
that they are arranged with the spaces of successive bags angularly
offset relative to each other so that said spaces are out of
register with each other when viewed lengthwise relative to the
series.
[0031] The invention will now be further described, by way of
example, with reference to the accompanying diagrammatic drawings,
in which:
[0032] FIG. 1 is a schematic three-dimensional view of a bag for
use in spacing apart a hanging wall and a foot wall in an
underground mine working, in accordance with the invention;
[0033] FIG. 2 is a view corresponding to FIG. 1, but rotated
through 180.degree. about a vertical axis; and
[0034] FIG. 3 is a schematic side elevation of an installation in
accordance with the invention which includes a plurality of the
bags of FIG. 1, spacing apart a hanging wall and a foot wall of a
stope in an underground mine working in accordance with the method
of the invention.
[0035] In the drawings, reference numeral 10 generally indicates a
bag for use in supporting a hanging wall 12 over a foot wall 14
(FIG. 3) in an underground mine working, in accordance with the
invention.
[0036] The bag 10 has walls of flexible sheet material, in this
case woven polypropylene, and a valve 16 forming a charging
connector for connection to a source (not shown) of flowable
substance under pressure to expand the bag 10. The bag 10 has a
pair of load-bearing walls 18, and an intermediate wall 20
extending between the load bearing walls 18.
[0037] Each load-bearing wall 18 is more or less square in outer
peripheral outline, when viewed face-on, and is provided with a
part-circular opening 22 which is located centrally in the
load-bearing wall 18. It should be appreciated that, in other
examples, the outer peripheral outline of the load-bearing walls 18
need not be square, but can have any desired shape, such as being
circular, in which case the bag 10 is broadly annular or
doughnut-shaped. An open ended slot 24 extends radially between the
central opening 22 and the outer periphery 26 of each load-bearing
wall 18, such that the slot 24 intersects both the opening 22 and
the outer periphery 26 of the load-bearing wall 18. Each
load-bearing wall 18 thus has an entire periphery constituted by
its outer periphery 26 and its inner periphery 28, which inner
periphery 28 extends along and includes both the edge of the
opening 22 and the opposed edges of the slot 24. This provides the
bag, when expanded as shown in FIGS. 1 and 2, with a centrally
located passage extending therethrough from one wall 18 to the
other; and an open ended space intersecting and extending between
the centrally located passage and the outer periphery of the bag,
the outer periphery of the bag being provided by that part of the
wall 20 which provides the square outer peripheral outline of the
bag, the inner periphery of the bag, in contrast, being the part of
its periphery which defines the space and the centrally located
passage.
[0038] The load bearing-walls 18 are connected together by the
intermediate wall 20 which extends between the load-bearing walls
18, the intermediate wall 20 being connected to both load-bearing
walls 18 along the entire periphery of each load-bearing wall 18 by
stitching 30. The intermediate wall 20 comprises a single
continuous panel extending along the entire periphery, i.e. both
the inner periphery 28 and the outer periphery 26, of the bag 10,
so that the interior of the bag 10 is sealed off. However, in other
examples of the invention, the intermediate wall 20 may consist of
a plurality of panels which are connected together end-to-end. The
width W of the intermediate wall 20, in a direction normal to and
from the one load-bearing wall 18 to the other, is about 25 cm.
[0039] The valve 16 is in the form of a non-return inlet valve
which is provided in, and extends through, a portion of the
intermediate wall 20 which is diametrically opposed, relative to
the central passage, to the open-ended space.
[0040] The bag 10 is also provided with a restraining arrangement
in the form of three pairs 36 of ties 38, each tie 38 being
anchored to the intermediate wall 20 at the end of the open-ended
space remote from the central passage. The pairs of ties 38 are
arranged in a series extending from one load-bearing wall 18 to the
other, across the intermediate wall 20 at the outer end of the
open-ended space, the ties 38 of each pair respectively being on
opposite sides of said outer end. Thus, the anchorages of the ties
38 of each pair 36 are respectively located on opposite sides of
the open-ended space, with the ties 38 of each pair adjacent a
load-bearing wall 18 respectively being anchored along opposite
edges of the associated slot 24, and having end portions 39
projecting from the inner ends of said edges and providing a
further pair of ties adjacent the central opening 22. It will be
appreciated that in use, the further pair of ties 39 will further
resist undesired widening of the open ended space, at its end
adjacent the central passage. In other examples of the invention,
instead of ties 38, the bag 10 can be provided with a restraining
arrangement in the form of webbing, hook-and-loop fasteners such as
those known under the Trade Mark "Velcro", or any other suitable
restraining arrangement.
[0041] In use, a plurality of the bags 10 is used in combination
with a support prop or strut 40 which is held captive between the
hanging wall 12 and the foot wall 14 (FIG. 3) of a stope 42 in an
underground mine working by abutment of an upper end 44 and a lower
end 46 of the strut 40 respectively against the hanging wall 12 and
the foot wall 14, with the strut 40 under compression.
[0042] The bags 10 are positioned on the strut 40 such that the
strut 40 is received in the central passage of each bag 10, the
bags 10 extending in series in a stacked arrangement along the
strut 40. Thereafter, the ties 38 of each pair 36 are fastened
together. The bags 10 are arranged on the strut 40 such that the
open-ended spaces and slots 24 of successive bags 10 are offset by
180.degree., being out of register, in plan view, extending in
diametrically opposed directions from the central passage.
[0043] The charging connectors 16 of the bags 10 are then connected
in turn to the source of flowable substance under pressure for
charging of the bag 10 with the flowable substance to expand the
bag 10. In this example, the flowable substance is cementitious
slurry or grout, the walls 18, 20 of the bag 10 being pervious to
water in the slurry but impervious to cementitious solids in the
slurry, so that the bags 10 are so-called weeping bags. In other
examples of the invention, the flowable substance can be a slurry
with water of any other suitable particulate settable cementitious
material, or indeed it can be a liquid, such as water. In the case
where the flowable substance is water, the bags 10 should of course
be impervious to water, to form so-called non-weeping bags. The
bags 10 are expanded one by one, starting with a lowermost bag 10
and ending with an uppermost bag 10.
[0044] Upon expansion of each bag 10, the load-bearing walls 18 of
the bag 10 are displaced away from each other and the intermediate
wall 18 is stretched taut, so that the entire peripheries of the
load-bearing walls 18 are vertically spaced apart. During expansion
of each bag 10, widening of the open-ended space of the bag 10 by
displacement of portions of the intermediate wall 18 which face
each other across the open-ended space away from each other, which
could lead to undesired disengagement or displacement of the bag 10
from the strut 40, is inhibited by the fastened-together ties
38.
[0045] The bags 10 are charged with grout or slurry such that the
uppermost bag 10 abuts against the hanging wall 12 and exerts a
desired supporting force on the hanging wall 12, the bags being
placed under compression. The grout in the bags 10 is then allowed
to set, so that the stacked bags 10 and the strut 40 form a
composite support installation 48 under compression for supporting
the hanging wall 12 above the foot wall 14.
[0046] In a further use, the bag 10 can be retro-fitted on an
existing support installation (not shown) which comprises a support
strut surrounded by a stacked series of doughnut-shaped bags, to
replace any doughnut-shaped bag which has burst or otherwise
failed; and bags 10 can if desired, be stacked around struts 40
which were originally installed without bags.
[0047] It is an advantage of the invention as described with
reference to the drawings that the bags 10 can be stacked around on
an existing support strut 40 which has already been positioned
between the hanging wall 12 and foot wall 14 to form a composite
support installation 48. The bag 10 is constructed such that it can
be expanded to a height which is sufficiently great to permit the
formation of a stacked arrangement which extends from the foot wall
14 to the hanging wall 12 by an acceptably small number of bags
10.
[0048] As the bags 10 have substantially parallel, more or less
flat load-bearing faces 18 when charged, the stacked arrangement of
bags 10 is also more stable than stacked arrangements of some
existing bags of which the load-bearing walls are directly
connected together along their edges, so that they are convex when
charged.
* * * * *