AU2019101376A4 - Explosion suppression method and apparatus - Google Patents
Explosion suppression method and apparatus Download PDFInfo
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- AU2019101376A4 AU2019101376A4 AU2019101376A AU2019101376A AU2019101376A4 AU 2019101376 A4 AU2019101376 A4 AU 2019101376A4 AU 2019101376 A AU2019101376 A AU 2019101376A AU 2019101376 A AU2019101376 A AU 2019101376A AU 2019101376 A4 AU2019101376 A4 AU 2019101376A4
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- mouth
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- 238000004880 explosion Methods 0.000 title claims abstract description 156
- 238000000034 method Methods 0.000 title claims abstract description 63
- 230000001629 suppression Effects 0.000 title description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 229
- 239000002817 coal dust Substances 0.000 claims abstract description 30
- 238000007789 sealing Methods 0.000 claims abstract description 19
- 239000003245 coal Substances 0.000 claims abstract description 17
- 238000011049 filling Methods 0.000 claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 claims description 37
- 239000002184 metal Substances 0.000 claims description 37
- 150000003839 salts Chemical class 0.000 claims description 33
- 239000000126 substance Substances 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 16
- 159000000003 magnesium salts Chemical class 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 229940050906 magnesium chloride hexahydrate Drugs 0.000 claims description 6
- 239000000853 adhesive Substances 0.000 claims description 5
- 230000001070 adhesive effect Effects 0.000 claims description 5
- DHRRIBDTHFBPNG-UHFFFAOYSA-L magnesium dichloride hexahydrate Chemical group O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-] DHRRIBDTHFBPNG-UHFFFAOYSA-L 0.000 claims description 5
- WRUGWIBCXHJTDG-UHFFFAOYSA-L magnesium sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Mg+2].[O-]S([O-])(=O)=O WRUGWIBCXHJTDG-UHFFFAOYSA-L 0.000 claims description 5
- 239000002985 plastic film Substances 0.000 claims description 3
- 239000000428 dust Substances 0.000 description 49
- 239000004575 stone Substances 0.000 description 45
- 230000004888 barrier function Effects 0.000 description 31
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 30
- 239000000377 silicon dioxide Substances 0.000 description 14
- 239000004033 plastic Substances 0.000 description 11
- 229920003023 plastic Polymers 0.000 description 11
- 239000002585 base Substances 0.000 description 10
- 239000007788 liquid Substances 0.000 description 10
- -1 salt magnesium chloride hexahydrate Chemical class 0.000 description 9
- 239000002245 particle Substances 0.000 description 8
- 238000002425 crystallisation Methods 0.000 description 7
- 238000002156 mixing Methods 0.000 description 6
- 230000008025 crystallization Effects 0.000 description 5
- 238000009434 installation Methods 0.000 description 5
- 239000002105 nanoparticle Substances 0.000 description 5
- 150000004677 hydrates Chemical class 0.000 description 4
- 230000002209 hydrophobic effect Effects 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000002826 coolant Substances 0.000 description 3
- 239000000839 emulsion Substances 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical class [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000002939 deleterious effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- PYLIXCKOHOHGKQ-UHFFFAOYSA-L disodium;hydrogen phosphate;heptahydrate Chemical compound O.O.O.O.O.O.O.[Na+].[Na+].OP([O-])([O-])=O PYLIXCKOHOHGKQ-UHFFFAOYSA-L 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004945 emulsification Methods 0.000 description 2
- 239000003995 emulsifying agent Substances 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 229910021485 fumed silica Inorganic materials 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229910021653 sulphate ion Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-L Phosphate ion(2-) Chemical compound OP([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-L 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001449 anionic compounds Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 description 1
- 229910000397 disodium phosphate Inorganic materials 0.000 description 1
- 235000019800 disodium phosphate Nutrition 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000006253 efflorescence Methods 0.000 description 1
- 230000001804 emulsifying effect Effects 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-M hydrogensulfate Chemical compound OS([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-M 0.000 description 1
- 229910001412 inorganic anion Inorganic materials 0.000 description 1
- 210000003141 lower extremity Anatomy 0.000 description 1
- NEMFQSKAPLGFIP-UHFFFAOYSA-N magnesiosodium Chemical class [Na].[Mg] NEMFQSKAPLGFIP-UHFFFAOYSA-N 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- MJMDTFNVECGTEM-UHFFFAOYSA-L magnesium dichloride monohydrate Chemical class O.[Mg+2].[Cl-].[Cl-] MJMDTFNVECGTEM-UHFFFAOYSA-L 0.000 description 1
- SWHAQEYMVUEVNF-UHFFFAOYSA-N magnesium potassium Chemical class [Mg].[K] SWHAQEYMVUEVNF-UHFFFAOYSA-N 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 229940091250 magnesium supplement Drugs 0.000 description 1
- LFCFXZHKDRJMNS-UHFFFAOYSA-L magnesium;sulfate;hydrate Chemical class O.[Mg+2].[O-]S([O-])(=O)=O LFCFXZHKDRJMNS-UHFFFAOYSA-L 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003094 microcapsule Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 150000004686 pentahydrates Chemical class 0.000 description 1
- UEZVMMHDMIWARA-UHFFFAOYSA-M phosphonate Chemical compound [O-]P(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-M 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- YPPQYORGOMWNMX-UHFFFAOYSA-L sodium phosphonate pentahydrate Chemical compound [Na+].[Na+].[O-]P([O-])=O YPPQYORGOMWNMX-UHFFFAOYSA-L 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- KRAHLZAGPKKBSW-UHFFFAOYSA-N tetrasodium;dioxidophosphanyl phosphite Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])OP([O-])[O-] KRAHLZAGPKKBSW-UHFFFAOYSA-N 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F5/00—Means or methods for preventing, binding, depositing, or removing dust; Preventing explosions or fires
- E21F5/14—Fluid barriers or rock dusters made to work by, or at the same time as, shots or explosions
- E21F5/143—Fluid barriers
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F5/00—Means or methods for preventing, binding, depositing, or removing dust; Preventing explosions or fires
- E21F5/02—Means or methods for preventing, binding, depositing, or removing dust; Preventing explosions or fires by wetting or spraying
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)
- Filtering Of Dispersed Particles In Gases (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
H:Inerwoven\NRPortbl\DCC\EVK\19510564_ldocx-S /1l2019 - 25 A method for use in suppressing a coal dust explosion in an underground coal mine, the method including: filling a bag with a quantity of explosion suppressant, the bag being configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion, the explosion suppressant including water or a source of water; sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag; and suspending the bag from a support structure in the mine. Fig. 3 Fill bag with explosion suppressant including water 300 or a source of water Seal open mouth of the bag so that explosion suppressant is 310 sealed inside the bag Suspend bag from support 320 structure in mine Explosion in mine -F Bag ruptures to thereby release explosion 340 suppressant for suppressing the explosion Fig. 3
Description
[0001] This application claims the benefit of Australian Provisional Patent Application No. 2018904292, filed on 9 November 2018, which is hereby incorporated by reference in its entirety.
Background of the Invention [0002] The present invention relates to a method and apparatus for suppressing explosions, being especially suitable for suppressing coal dust explosions in underground coal mines.
Description of the Prior Art [0003] In underground coal mines, a coal dust explosion occurs when a combustible concentration of coal dust is lifted into mine roadways and ignited. For example, the ignition of a small quantity of methane gas generates a pressure wave which lifts coal dust that has accumulated on the roadway surfaces into the air. The associated methane flame ignites the coal dust. Without some means of limiting the reaction, coal dust will continue to lift and burn and create an even larger pressure wave, and a coal dust explosion will propagate through the mine.
[0004] Almost all underground coal mines require some special protection systems to prevent the widespread propagation of a dust explosion. Traditionally, this has involved the use of an inertant in the form of a non-ignitable dust, commonly known as stone dust (or rock dust in some regions). This is typically ground limestone dust. The stone dust may be sprayed over mine roads and/or blown into the ventilating air and allowed to settle on surfaces within the mine. In some mines, large deposits of stone dust, known as passive barriers, may be strategically placed around the mine. These passive barriers generally consist of a framework upon which loose stone dust is placed or water tubs are suspended. The successful operation of any passive barrier is dependent on the explosion pressure and time delay between arrival of pressure front and flame at barrier site to distribute the inertant into the flame, and the specific rupture characteristics of the barrier components. Traditional stone dust shelf and water trough passive barriers require high explosion pressures to operate.
H:\Interwoven\NRPortb1\DCC\EVK\19510564_l.docx-8/11/2019
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-2[0005] More recently, bag barrier systems, such as the SkillPro-CSIR Bag Barrier system offered in Australia by SkillPro Services Pty Ltd, have seen widespread use in coal mines. A bag barrier consists of an array of specially made plastic bags, each typically holding 6kg of stone dust. The plastic bag is designed to shred easily under explosion pressure to disperse dust. A plastic hook and ring arrangement is used to seal and hang the bag from the mine roof. The plastic bags provide protection against moisture to prevent caking of stone dust and allowing ease of installation. The plastic bags also allow easy visual inspection and repair of barrier. A bag barrier system provides great flexibility to handle obstructions such as vent ducting, monorails and conveyor belts.
[0006] Stone dust bags for use in the above discussed bag barrier systems were originally invented by the South African Council for Scientific and Industrial Research (CSIR) and disclosed in South African Patent No. 1995/10599. One aspect of the invention disclosed in this patent concerns a stone dust bag apparatus which includes a bag for containing stone dust. Figures 1 and 2 are reproduced from the aforementioned patent and show further details of this prior art stone dust bag. The bag is made of plastics material and is arranged to rupture, thereby releasing the stone dust, when subjected to an explosion-induced pressure wave in a mine working. The apparatus also includes a support arrangement for supporting and sealing the open mouth of the bag. The support arrangement has a former which is located in the mouth of the bag and a clamping ring which cooperates with the former to clamp the mouth of the bag.
[0007] Bag barrier systems have proven to be effective and economical and the above mentioned SkillPro-CSIR Bag Barrier system has almost completely replaced traditional shelf-style stone dust barriers and water trough barriers in Australia and South Africa. Nevertheless, there are some limitations associated with the use of stone dust in bag barrier systems. For example, since stone dust acts as an inertant for suppressing the combustion of the coal dust, large quantities of stone dust are required to provide adequate explosion suppression, necessitating the use of large arrays of plastic bags which require significant effort and expense associated with filling and handling the bags during installation. It would be desirable to offer an alternative solution that provides explosion suppression performance
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-3 that is at least comparable to or better than stone dust bag barrier systems, with a meaningful reduction in the associated downsides.
[0008] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
Summary of the Present Invention [0009] In one broad form an aspect of the present invention seeks to provide a method for use in suppressing a coal dust explosion in an underground coal mine, the method including: filling a bag with a quantity of explosion suppressant, the bag being configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion, the explosion suppressant including water or a source of water; sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag; and, suspending the bag from a support structure in the mine.
[0010] In one embodiment, the explosion suppressant is water.
[0011] In one embodiment, the explosion suppressant includes a source of water that includes a solid-state substance comprising bound water, the source of water being selected so that at least some of its bound water is available to absorb heat energy from the explosion.
[0012] In one embodiment, the source of water comprises at least 50% w/w bound water.
[0013] In one embodiment, the source of water is an inorganic hydrate.
[0014] In one embodiment, the inorganic hydrate is a hydrated metal salt.
[0015] In one embodiment, the hydrated metal salt includes 4 to 12 molecules of bound water per molecule of metal salt.
[0016] In one embodiment, the hydrated metal salt is a hydrated magnesium salt.
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-4[0017] In one embodiment, the hydrated metal salt is magnesium chloride hexahydrate or magnesium sulphate heptahydrate.
[0018] In one embodiment, the source of water is a micro-encapsulated source of water.
[0019] In one embodiment, the source of water is dry water.
[0020] In one embodiment, the source of water is a powder.
[0021] In one embodiment, the bag is formed from a material that is substantially impervious to water.
[0022] In one embodiment, the method includes suspending the bag from the support structure using a hook attached to the bag.
[0023] In one embodiment, sealing the open mouth of the bag includes forming a seal between opposing sides of the mouth of the bag using at least one of: stitching; a heat seal; a chemical seal; an adhesive; and, mechanical fasteners.
[0024] In one embodiment, sealing the open mouth of the bag includes forming a folded edge that is attached to a sidewall of the bag to define a conduit extending around the mouth of the bag, the conduit including open ends, and wherein the method includes threading an elongate member through the conduit, the elongate member being used for suspending the bag from the support structure.
[0025] In one embodiment, suspending the bag from the support structure includes looping the elongate member around the support structure.
[0026] In one embodiment, sealing the open mouth of the bag includes locating a former in the mouth of the bag and using a clamping ring in cooperation with the former to clamp the mouth of the bag.
[0027] In one embodiment, the method includes suspending the bag from the support structure using a support arrangement that is attached to the former.
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-5 [0028] In one embodiment, the method includes suspending the bag from the support structure using a support arrangement that is formed integrally with the former.
[0029] In one embodiment, the method is for use in suppressing a coal dust explosion in an underground coal mine.
[0030] In one embodiment, the method includes: filling a plurality of bags with a quantity of explosion suppressant; sealing the plurality of the bags; and, suspending the plurality of the bags from support structures in a mine area, the bags being arranged in an array to allow explosion suppressant to be distributed throughout the mine area in the event of an explosion.
[0031] In one broad form an aspect of the present invention seeks to provide apparatus for use in suppressing a coal dust explosion in an underground coal mine, the apparatus including: a bag filled with a quantity of explosion suppressant, the bag being configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion, the explosion suppressant including water or a source of water; a seal arrangement for sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag; and, a support arrangement for suspending the bag from a support structure in the mine.
[0032] In one embodiment, the explosion suppressant is water.
[0033] In one embodiment, the explosion suppressant includes a source of water that includes a solid-state substance comprising bound water, the source of water being selected so that at least some of its bound water is available to absorb heat energy from the explosion.
[0034] In one embodiment, the source of water comprises at least 50% w/w bound water.
[0035] In one embodiment, the source of water is an inorganic hydrate.
[0036] In one embodiment, the inorganic hydrate is a hydrated metal salt.
[0037] In one embodiment, the hydrated metal salt includes 4 to 12 molecules of bound water per molecule of metal salt.
[0038] In one embodiment, the hydrated metal salt is a hydrated magnesium salt.
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-6[0039] In one embodiment, the hydrated magnesium salt is magnesium chloride hexahydrate or magnesium sulphate heptahydrate.
[0040] In one embodiment, the source of water is a micro-encapsulated source of water.
[0041] In one embodiment, the source of water is dry water.
[0042] In one embodiment, the source of water is a powder.
[0043] In one embodiment, the bag is formed from a material that is substantially impervious to water.
[0044] In one embodiment, the bag is formed from a sheet material that is relatively weaker in a first direction and relatively stronger in a second direction that is perpendicular to the first direction.
[0045] In one embodiment, the bag includes a base opposing the mouth, such that the first direction is oriented in a longitudinal direction extending between the mouth and the base, and the second direction is oriented in a lateral direction extending perpendicular to the longitudinal direction.
[0046] In one embodiment, the bag is formed from an anisotropic plastic sheet.
[0047] In one embodiment, the support arrangement includes a hook.
[0048] In one embodiment, the seal arrangement includes a former that is located in the mouth of the bag and a clamping ring that cooperates with the former to clamp the mouth of the bag.
[0049] In one embodiment, the support arrangement is attached to the former.
[0050] In one embodiment, the support arrangement is formed integrally with the former.
[0051] In one embodiment, the seal arrangement includes a seal formed between opposing sides of the mouth of the bag using at least one of: stitching; a heat seal; a chemical seal; an adhesive; and, mechanical fasteners.
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-7 [0052] In one embodiment, the seal arrangement includes a folded edge that is attached to a sidewall of the bag to define a conduit extending around the mouth of the bag, the conduit including open ends, and wherein the support arrangement includes an elongate member that is threaded through the conduit and used to suspend the bag from the support structure.
[0053] In one embodiment, the elongate member is configured to be looped around a support structure in the mine to suspend the bag from the support structure.
[0054] It will be appreciated that the broad forms of the invention and their respective features can be used in conjunction, interchangeably and/or independently, and reference to separate broad forms is not intended to be limiting.
Brief Description of the Drawings [0055] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: [0056] Figure 1 is an exploded side view of a prior art stone dust bag apparatus;
[0057] Figure 2 is a partial cross-section view of the assembled prior art stone dust bag apparatus of Figure 1; and, [0058] Figure 3 is a flow chart of a method for use in suppressing an explosion in a mine.
Detailed Description of the Preferred Embodiments [0059] An example of a method and associated apparatus for suppressing a coal dust explosion in an underground coal mine will now be described.
[0060] With regard to Figure 3, a method for use in suppressing a coal dust explosion in an underground coal mine broadly includes the following steps. The initial step 300 involves filling a bag with a quantity of explosion suppressant. The bag is configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion. The explosion suppressant includes water or a source of water. The following step 310 involves sealing an open mouth of the bag so that the explosion
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-8suppressant is sealed inside the bag. Then, step 320 involves suspending the bag from a support structure in the mine.
[0061] Since the bag is configured to rupture when subjected to an explosion-induced pressure wave, in the event of an explosion in the mine as indicated in step 330, the bag will rupture to thereby release the explosion suppressant for suppressing the explosion as indicated at step 340. It should be understood that steps 330 and 340 do not form steps of the method themselves but are provided to better illustrate how explosions may be suppressed as a result of performing the method.
[0062] It will also be appreciated that a corresponding apparatus for use in suppressing a coal dust explosion in an underground coal mine may include a bag filled with a quantity of explosion suppressant including water or a source of water, a seal arrangement for sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag, and a suspension arrangement for suspending the bag from a support structure in the mine. As mentioned above, the bag is configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion.
[0063] It should be understood that this method and apparatus may be implemented at scale to provide effective explosion suppression in large mine environments. In practice, this would typically involve filling a plurality of bags with a quantity of explosion suppressant, sealing the plurality of the bags and suspending the plurality of the bags from support structures in a mine area, the bags being arranged in an array to allow explosion suppressant to be distributed throughout the mine area in the event of an explosion.
[0064] The configuration of the array such as the number of bags and spacing between bags may be selected depending on the quantity of explosion suppressant provided in each bag, the specific explosion suppression characteristics of the explosion suppressant, the size of the mine area, and potentially a range of other characteristics of the mine and type of explosions that may need to be suppressed.
[0065] In the above described method and apparatus, the explosion suppressant particularly includes water or a source of water, which can be contrasted with traditional stone dust bag
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-9 barrier systems for explosion suppression in coal mines, in which bags are filled with stone dust.
[0066] When used herein, the term source of water refers to a substance comprising bound water in the form of water of crystallization, water of hydration, encapsulated water or the like. Examples of suitable sources of water will be described in further detail below, but in preferred embodiments in which the explosion suppressant includes a source of water, this will typically include a solid-state substance comprising bound water, the source of water being selected so that at least some of its bound water is available to absorb heat energy from the explosion. Without being bound by theory, it is believed that a source of water as defined herein absorbs more heat energy than an equivalent mass of powdered mineral inertants such as stone dust.
[0067] For instance, the source of water may absorb heat energy whilst its water remains substantially bound. However, it will be appreciated that in some circumstances the source of water may release at least a portion, or substantially all, of its bound water in response to a physical stimulus such as heat. In some embodiments, the source of water may release substantially all its bound water at temperatures of approximately 100 °C, or greater. When exposed to explosion conditions such as heat and/or blast wave, the source of water may release at least a portion of its bound water in a finely divided form. This may simultaneously or subsequently increase in temperature as it absorbs energy from the explosion and may ultimately be converted to gaseous form.
[0068] It will be appreciated that such a source of water is preferably in a solid state. Preferably it is in a finely divided or particulate form, such as a powder, to facilitate rapid dispersion and rapid release of water under conditions of explosion. Alternatively, the source of water may be in a physical form that readily produces a finely divided source of water under explosion conditions.
[0069] In any event, the use of an explosion suppressant including water or a source of water in the method and apparatus described above may provide important advantages compared to the use of stone dust in traditional bag barrier systems. In this regard, it should be appreciated that when stone dust is used as an inertant in coal mines, its explosion
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- 10suppression performance primarily depends on providing a sufficient quantity of stone dust to effectively act as a heat sink to absorb the heat of combustion of the coal and therefore reduce the overall temperature of the coal dust, inertant and air to suppress the propagation of the explosion through the mine, in other words to serve as a physical barrier to reduce heat transfer between the coal dust particles present in the mine. On the other hand, although water can act as an inertant in a similar manner, water also has a relatively large heat capacity, thus it is also useful as a coolant to retard reaction rates in the explosion. Water is a particularly effective explosion suppressant primarily due to its high enthalpy of vaporisation (40.65 kJmol1), due to energy required to overcome hydrogen bonding present in liquid water. Whilst stone dust will absorb some heat in an explosion, the heat capacity of stone dust is significantly lower than water and its effectiveness as a coolant is negligible compared to that of water.
[0070] These combined inertant and coolant qualities of water can allow a given quantity of an explosion suppressant including water or a source of water to provide the same explosion suppression performance as a significantly larger quantity of stone dust. Accordingly, when using the present method and apparatus for explosion suppression in a mine, a smaller quantity of explosion suppressant may be provided compared to a stone dust bag barrier system of equivalent explosion suppression performance. In practice, this will reduce the number of bags required for installation in a mine area, thereby reducing the associated effort and expense of filling and handling the bags during installation.
[0071] Research by the applicant and others has confirmed that water is an effective inertant for suppressing coal dust explosions. It is noted that, prior to the advent of stone dust bag barriers, water was traditionally used as an inertant, deployed in the mine in tubs and suspended from steel frames erected in the roadway. Highly developed coal dust explosions appear to be better suppressed by water, but like stone dust, liquid water can have its own issues. Despite its simplicity, holding water in tubs in the traditional manner meant there was often extensive evaporation as it was exposed to the mine ventilating air. The tubs could not be effectively sealed, and they were time consuming to erect and fill. They were all but impossible to move once filled.
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- 11 [0072] In contrast, the use of a bag barrier style system as described above enables water to be used in explosion suppression barriers with little to no maintenance of the barrier system. However, it has also been found that certain solid-state water sources can act in much the same way as liquid water, to thereby provide a suitable source of water as discussed above, without the same practical downsides.
[0073] For example, a range of known man-made substances exist which may function as a source of water yet, under standard conditions, exist in a non-liquid form. Examples of such substances include micro-encapsulated substances wherein tiny droplets of water are surrounded by a coating, such as a polymer, silica or other material, to give micro-capsules of water. In some forms, micro-encapsulated water may be referred to collectively by the term “dry water”. In some aspects, dry water includes an air-water emulsion which may be formed by combining silica and water together, for example by blending hydrophobic silica nanoparticles and liquid water under controlled conditions. The physical properties and chemical composition of dry water can vary, and will depend on several factors such as the relative ratio of silica to water and the method of preparation. Generally, during preparation, the hydrophobic silica nanoparticles surround individual water droplets to produce a substance that is a dry powder in appearance and physical characteristics, but potentially comprises up to about 98 or 99% by mass of water. As a result, “dry water” may act as an explosion suppressant with performance similar to liquid water when exposed to a coal dust explosion. Small scale testing by the applicant has shown that dry water is up to six times more effective that stone dust in suppressing coal dust combustion.
[0074] A number of naturally occurring, man-made or man-modified inorganic hydrates can also contain sufficient water of crystallisation to work much the same as liquid water in relation to suppression of a coal dust explosion. One such inorganic hydrate that has been tested to suppress coal dust explosions is the hydrated metal salt magnesium chloride hexahydrate. Characteristic features of suitable hydrated metal salts include a high proportion of water of crystallisation and physical stability in its finely divided form under ambient conditions. Small scale testing by the applicant has shown several hydrated metal salts behave almost the same as liquid water when exposed to a coal dust explosion.
[0075] Further preferred or optional features of the source of water will now be described.
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- 12[0076] In some examples, the source of water may have an average particle size similar to that commonly found in coal dust particles, for example the particle size may have an average diameter of <500 pm, and preferably <250 pm. In some examples, the average particle diameter is about 20 pm to about 400 pm, for example about 100 pm to about 300 pm or about 100 pm to about 300 pm.
[0077] Examples of sources of water may include hydrated polymers, micro-encapsulated water and inorganic hydrates.
[0078] In order to reduce time and costs associated with maintenance of the explosion suppressing system it is advantageous if the source of water can remain underground in a mining environment for extended periods of time without significant degradation or loss of effectiveness. Preferably the explosion suppression apparatus can remain in place for up to six months or up to one year without any appreciable deleterious effects. Accordingly, the source of water preferably does not lose any appreciable amount of water on storage. It is noted that the design of the bag plastic and its sealing arrangement may both contribute to limiting water loss. Similarly, the source of water is preferably substantially non-hygroscopic or substantially non-caking on storage under conditions of temperature and humidity as typically found in a mine. Preferably the source of water is substantially non-deliquescent and non-efflorescent under typical mine conditions.
[0079] Due to the requirement for the source of water to be located in areas where mining personnel may be present, the source of water should be substantially non-toxic and nonirritant both during storage and under explosion conditions. Furthermore, the source of water should not release any appreciable amount of toxic or hazardous components under explosion conditions, nor should it release an explosion accelerant.
[0080] As the source of water may be required in large amounts to provide an effective explosion suppression system in a given area, preferably the source of water is readily available and cost effective.
[0081] In some embodiments, sources of water are those comprising greater than 40% w/w water, greater than 50% w/w water, greater than 55% w/w water or greater than 60% w/w water. In some examples, the source of water may comprise up to 98%, up to 96% w/w or up
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- 13 to 95% w/w water, for example 40-97% w/w water, 40-95% w/w water, 50-95% w/w water, 55-95% w/w water or 60-98% water.
[0082] An example of micro-encapsulated sources of water is dry water, also known as powdered water. Dry water includes water/air emulsions comprising silica as an emulsifying agent. In some embodiments, the water/air emulsions comprise droplets of water surrounded by a silica coating. In some embodiments, the emulsifying agent comprises hydrophobic fumed silica nanoparticles.
[0083] The physical properties and composition of dry water will vary in accordance with the process of manufacture. Dry water typically consists of 75-98% w/w water; for example 93-98% w/w water, 95-98% w/w water, or 97-98% w/w water; or approximately 95%, 97% or 98% w/w water. Dry water may be prepared from silica nanoparticles and water in accordance with known methods, for example the methods as described in US 4008170A(US Secretary of Army), EP1787958A1 (Evonik Degussa GmbH) and EP1787957A1 (Evonik Degussa GmbH). Typical average dry water particle diameters range from 20 to 400 pm, for example 100 to 200 pm.
[0084] In some embodiments, dry water may be prepared by mixing hydrophobic fumed silica nanoparticles with liquid water. It will be appreciated that mixing should be performed under conditions sufficient to effect emulsification. Preferably, the Reynolds number (ratio between the inertial forces in the fluid and the viscous forces) achieved during mixing is in excess of about 60,000. In some embodiments, the mixing is carried out at ambient temperatures. Typical proportions of silica to water used in the manufacture of dry water include from about 1 part silica to 30 parts water to about 1 part silica to 50 parts water. In some embodiments, the approximate proportion is 1 part silica to 40 parts water. The silica and water may be combined using conventional techniques and methodology well known in the art. Equipment for mixing and effecting emulsification is well known to those skilled in the art and is readily available from commercial sources. Those skilled in the art will readily be able to select suitable equipment in accordance with the required scale and batch size. In some embodiments, batches of dry water of about 20 litres can be produced after combining the silica and water for a few minutes under emulsifying conditions. However, it will be appreciated that larger batches may be prepared if required.
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- 14[0085] Other suitable sources of water include inorganic hydrates. Particular examples of inorganic hydrates include metal salts comprising bound water, for example crystalline metal salt hydrates which comprise stoichiometric amounts of water in the form of water of crystallization. In some embodiments, metal salt hydrates comprise greater than 40% of bound water, preferably greater than 50% w/w of bound water. The metal salt hydrate may comprise up to about 70% w/w water. In some embodiments, a metal salt hydrate comprises 40-70% w/w water, 50-70% w/w water, 40-60% w/w water or 45-55% w/w water.
[0086] Examples of metal salt hydrates include hydrated salts of Group I metals (alkali metals) for example sodium or potassium; or hydrated salts of Group II metals (alkaline earth metals) for example, magnesium, or calcium.
[0087] Non-limiting examples of typical inorganic anions include carbonate, hydrogencarbonate, sulphate, hydrogensulphate, chloride, phosphonate, or hydrogenphosphate.
[0088] It will be appreciated that a metal salt hydrate may be a double salt hydrate containing more than one cation or more than one anion. Examples include sodium magnesium salts or potassium magnesium salts, particularly those salts with a sulphate anion.
[0089] It will be understood that it is advantageous to maximize the amount of water present in the salt without introducing any deleterious effects or unwanted properties. In some examples, hydrated metal salts include from 1 to 12, for example 4 to 10, molecules of water of crystallization per molecule of metal salt. Preferably, the metal salt has four, five, six, seven, eight or more molecules of water per molecule of metal salt.
[0090] Particular metal salt hydrates include hydrated magnesium salts. Examples include magnesium chloride hydrates (MgCh.nFEO, wherein l<n<6), for example magnesium chloride hexahydrate (MgCE.bFEO) which comprises 53.1% w/w water of crystallization. Further examples include magnesium sulphate hydrates (MgSCfi. nPEO, wherein l<n<7), particularly magnesium sulphate heptahydrate (MgSO^FEO) also know as Epsom salts, which comprises 51.1% w/w water of crystallization. Other examples of metal salt hydrates include sodium hydrogenphosphate heptahydrate (disodium phosphate heptahydrate,
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- 15 Na2HPO4, 45.5% w/w water) or sodium phosphonate pentahydrate (sodium diphosphite dibasic pentahydrate, Na2HPO3.5H2O, 41.7% w/w water).
[0091] Metal salt hydrates are well known and are readily available from commercial sources. They may be produced on an industrial scale in accordance with known methods, or may be obtained from natural mineral deposits. Where necessary, the particle size of metal salt hydrates may be reduced by crushing in accordance with known methods to provide a powder with an average particle diameter size of, for example, approximately 100 pm to 300 pm, 100 pm to 250 pm, or 100 pm to 200 pm.
[0092] As far as the structural elements of the present apparatus are concerned, in some examples, the bag, seal arrangement and support arrangement may be provided in accordance with the prior art stone dust bag apparatus disclosed by the South African Council for Scientific and Industrial Research (CSIR) in South African Patent No. 1995/10599 (“the CSIR patent”), the entire content of which is incorporated herein by reference. To provide further context for the present apparatus, features of the prior art stone dust bag will be described with regard to Figures 1 and 2 which are reproduced from the CSIR patent.
[0093] The prior art stone dust bag apparatus 10 illustrated in Figures 1 and 2 consists of a bag 12 and a support arrangement including a former 14 and a clamping ring 16. The bag 12 is of tubular form and has an open mouth 18 and a closed bottom 20. It is made of high density polyethylene and the bottom 20 is closed by means of a heat seal line 22.
[0094] The former 14 is injection moulded in one piece of plastics material. It includes a hollow base 24 with an external, conically tapered surface 26 and a circumferential lip 28 at the lower extremity of the base, and a hook 30 which projects upwardly from the upper wall 32 of the base. A reinforcing gusset 34 extends diametrically across the interior of the base and the hook is strengthened by triangular, radial gussets 36. The clamping ring 16 is of annular conical shape with an internal, conically tapered surface 38. It is also injection moulded in one piece of plastics material.
[0095] Suitable bags, seal arrangements, and support arrangements are commercially available as part of the SkillPro-CSIR Bag Barrier System offered by SkillPro Services Pty Ltd in Australia. Although this bag barrier system is provided for use with stone dust, the
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- 16structural elements may be effectively utilised in the embodiments of the present method and apparatus.
[0096] It is noted that, in the prior art stone dust bag systems such as those disclosed in the CSIR patent, the bag was filled with a predetermined quantity of stone dust in use. However, in the present method and apparatus, the bag is filled with a quantity of explosion suppressant which includes water or a source of water in place of stone dust as discussed above.
[0097] In any event, in example implementations of the present method and apparatus, once the bag is filled with the explosion suppressant, the sealing of the bag may be performed substantially as described in the CSIR patent. The base 24 is inserted into the open mouth 18 and the clamping ring 16 is then placed over the base. The taper surfaces 26 and 38 cooperate with one another to clamp the mouth of the bag between them. This not only secures the bag firmly to the former, but also seals the mouth of the bag on the former. The assembled apparatus can now be suspended from a suitable support structure in a mine.
[0098] In the above example, it will be appreciated that the seal arrangement of the present apparatus will be effectively provided by the support arrangement in use. However, in other examples, the bag, seal arrangement and/or support arrangement may be provided using alternative constructions which, for instance, may involve separate seal and support arrangements.
[0099] Further preferred or optional features of the structural elements of the present apparatus including the bag, seal arrangement and support arrangement will now be described.
[0100] Preferably, the bag is formed from a material that is substantially impervious to water, to thereby allow an explosion suppressant including liquid water or a suitable source of water to be contained inside the bag without substantial losses due to leakage or evaporation through the bag material. Similarly, the seal arrangement should be substantially impervious to water ingress after the explosion suppressant is sealed inside the bag. Such ingress could occur, for example, by the bags being suspended from the roof of a mine roadway where water was dripping out of the strata or sprayed from a fracture in a nearby high-pressure hose. It will also be appreciated that the bag should not react or be degraded by
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- 17any part of the explosion suppressant that fills the bag, for instance when the explosion suppressant includes a source of water that includes a solid-state substance comprising bound water.
[0101] As described above, the bag is configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion. This can be achieved in numerous ways, and several suitable examples are already discussed in the CSIR patent, such as by forming the bag of plastics material and including a zone of weakness at which the bag will rupture.
[0102] The bag may be formed from a sheet material that is relatively weaker in a first direction and relatively stronger in a second direction that is perpendicular to the first direction. In some embodiments, the bag includes a base opposing the mouth, such that the first direction is oriented in a longitudinal direction extending between the mouth and the base, and the second direction is oriented in a lateral direction extending perpendicular to the longitudinal direction. It will be appreciated that this may allow the bag to effectively bear the weight of the explosion suppressant material yet be more readily ruptured when exposed to forces that load the bag in the non-weight-bearing lateral direction, such as due to an explosion-induced pressure wave.
[0103] In some specific embodiments, this may be achieved by forming the bag from an anisotropic plastic sheet. The use of specially designed bags with anisotropic properties can allow the bags to rupture and release their payload of explosion suppression at lower pressures than required for other traditional water or stone dust barrier systems. As such, embodiments of the present apparatus can react to substantially lower explosion pressures and potentially stop explosions that would otherwise not be stopped.
[0104] In some examples, the support arrangement includes a hook, which can be conveniently used to hang the apparatus from a support structure in the mine, such as a mesh or framework provided on the mine roof, as discussed in further detail in the CSIR patent. However, it will be appreciated that the support arrangement may include any suitable device for supporting the apparatus from the support, by hanging or otherwise.
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- 18[0105] Specific examples of the seal arrangement may include a former that is in the mouth of the bag and a clamping ring that cooperates with the former to clamp the mouth of the bag, as in the prior art stone dust bag apparatus of Figures 1 and 2 as described above. The support arrangement, such as a hook as mentioned above, may be attached to the former. In some examples, the support arrangement may be formed integrally with the former.
[0106] However, in alternative implementations, the seal arrangement may include a seal formed between opposing sides of the mouth of the bag using stitching, a heat seal, a chemical seal, an adhesive, or mechanical fasteners. It will be appreciated that the use of such an alternative seal arrangement may necessitate the use of a different form of support arrangement.
[0107] In some examples, the seal arrangement may include a folded edge that is attached to a sidewall of the bag to define a conduit extending around the mouth of the bag, with the conduit including open ends. In this case, the support arrangement may include an elongate member that is threaded through the conduit and used to suspend the bag from the support structure. In some embodiments of this design, the elongate member may be configured to be looped around a support structure in the mine to suspend the bag from the support structure. In one specific embodiment, the elongate member may be a zip tie or the like. However, other embodiments may include a hook or the like attached to the threaded member, such that the threaded member is only used to interconnect the hook and the bag. It should be appreciated that the support arrangement should be configured to ensure that the bag can rupture and release its payload of explosion suppressant before failure of the support arrangement.
[0108] In any event, it will be appreciated that embodiments of the above described method and apparatus for suppressing an explosion in a mine may provide an improved explosion suppression solution compared to convention techniques including the stone dust bag barrier systems commonly employed today. As described above, the use of an explosion suppressant including water, or a source of water can provide enhanced performance in the suppression of coal dust explosions compared to stone dust, since water can provide a significant cooling effect in an explosion, in addition to diluting the coal dust as per stone dust.
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- 19[0109] Accordingly, an explosion suppression system implementing the present method and apparatus may require fewer bags providing a reduced total quantity of explosion suppressant compared to a stone bag barrier system with comparable explosion suppression performance. It will be appreciated that this may realise substantial savings in the costs of materials, handling and labour required in the installation of such a system.
[0110] Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. As used herein and unless otherwise stated, the term approximately means ±20%.
[0111] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a support” includes a plurality of supports. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings unless a contrary intention is apparent.
[0112] It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.
Claims (45)
1) A method for use in suppressing a coal dust explosion in an underground coal mine, the method including:
a) filling a bag with a quantity of explosion suppressant, the bag being configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion, the explosion suppressant including water or a source of water;
b) sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag; and,
c) suspending the bag from a support structure in the mine.
2) A method according to claim 1, wherein the explosion suppressant is water.
3) A method according to claim 1, wherein the explosion suppressant includes a source of water that includes a solid-state substance comprising bound water, the source of water being selected so that at least some of its bound water is available to absorb heat energy from the explosion.
4) A method according to claim 3, wherein the source of water comprises at least 50% w/w bound water.
5) A method according to claim 3 or claim 4, wherein the source of water is an inorganic hydrate.
6) A method according to claim 5, wherein the inorganic hydrate is a hydrated metal salt.
7) A method according to claim 6, wherein the hydrated metal salt includes 4 to 12 molecules of bound water per molecule of metal salt.
8) A method according to claim 7, wherein the hydrated metal salt is a hydrated magnesium salt.
9) A method according to claim 8, wherein the hydrated metal salt is magnesium chloride hexahydrate or magnesium sulphate heptahydrate.
10) A method according to claim 3 or claim 4, wherein the source of water is a microencapsulated source of water.
11) A method according to claim 3 or claim 4, wherein the source of water is dry water.
12) A method according to any one of claims 1 to 11, wherein the source of water is a powder.
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13) A method according to any one of claims 1 to 12, wherein the bag is formed from a material that is substantially impervious to water.
14) A method according to any one of claims 1 to 13, wherein the method includes suspending the bag from the support structure using a hook attached to the bag.
15) A method according to any one of claims 1 to 14, wherein sealing the open mouth of the bag includes forming a seal between opposing sides of the mouth of the bag using at least one of:
a) stitching;
b) a heat seal;
c) a chemical seal;
d) an adhesive; and,
e) mechanical fasteners.
16) A method according to claim 15, wherein sealing the open mouth of the bag includes forming a folded edge that is attached to a sidewall of the bag to define a conduit extending around the mouth of the bag, the conduit including open ends, and wherein the method includes threading an elongate member through the conduit, the elongate member being used for suspending the bag from the support structure.
17) A method according to claim 16, wherein suspending the bag from the support structure includes looping the elongate member around the support structure.
18) A method according to any one of claims 1 to 14, wherein sealing the open mouth of the bag includes locating a former in the mouth of the bag and using a clamping ring in cooperation with the former to clamp the mouth of the bag.
19) A method according to claim 18, wherein the method includes suspending the bag from the support structure using a support arrangement that is attached to the former.
20) A method according to claim 19, wherein the method includes suspending the bag from the support structure using a support arrangement that is formed integrally with the former.
21) A method according to any one of claims 1 to 20, wherein the method is for use in suppressing a coal dust explosion in an underground coal mine.
22) A method according to any one of claims 1 to 21, wherein the method includes:
a) filling a plurality of bags with a quantity of explosion suppressant;
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b) sealing the plurality of the bags; and,
c) suspending the plurality of the bags from support structures in a mine area, the bags being arranged in an array to allow explosion suppressant to be distributed throughout the mine area in the event of an explosion.
23) Apparatus for use in suppressing a coal dust explosion in an underground coal mine, the apparatus including:
a) a bag filled with a quantity of explosion suppressant, the bag being configured to rupture when subjected to an explosion-induced pressure wave to thereby release the explosion suppressant for suppressing the explosion, the explosion suppressant including water or a source of water;
b) a seal arrangement for sealing an open mouth of the bag so that the explosion suppressant is sealed inside the bag; and,
c) a support arrangement for suspending the bag from a support structure in the mine.
24) Apparatus according to claim 23, wherein the explosion suppressant is water.
25) Apparatus according to claim 23, wherein the explosion suppressant includes a source of water that includes a solid-state substance comprising bound water, the source of water being selected so that at least some of its bound water is available to absorb heat energy from the explosion.
26) Apparatus according to claim 25, wherein the source of water comprises at least 50% w/w bound water.
27) Apparatus according to claim 25 or claim 26, wherein the source of water is an inorganic hydrate.
28) Apparatus according to claim 27, wherein the inorganic hydrate is a hydrated metal salt.
29) Apparatus according to claim 28, wherein the hydrated metal salt includes 4 to 12 molecules of bound water per molecule of metal salt.
30) Apparatus according to claim 29, wherein the hydrated metal salt is a hydrated magnesium salt.
31) Apparatus according to claim 30, wherein the hydrated magnesium salt is magnesium chloride hexahydrate or magnesium sulphate heptahydrate.
32) Apparatus according to claim 25 or claim 26, wherein the source of water is a microencapsulated source of water.
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33) Apparatus according to claim 25 or claim 26, wherein the source of water is dry water.
34) Apparatus according to any one of claims 25 to 33, wherein the source of water is a powder.
35) Apparatus according to any one of claims 23 to 34, wherein the bag is formed from a material that is substantially impervious to water.
36) Apparatus according to any one of claims 23 to 35, wherein the bag is formed from a sheet material that is relatively weaker in a first direction and relatively stronger in a second direction that is perpendicular to the first direction.
37) Apparatus according to claim 36, wherein the bag includes a base opposing the mouth, such that the first direction is oriented in a longitudinal direction extending between the mouth and the base, and the second direction is oriented in a lateral direction extending perpendicular to the longitudinal direction.
38) Apparatus according to claim 36 or 37, wherein the bag is formed from an anisotropic plastic sheet.
39) Apparatus according to any one of claims 23 to 38, wherein the support arrangement includes a hook.
40) Apparatus according to any one of claims 23 to 39, wherein the seal arrangement includes a former that is located in the mouth of the bag and a clamping ring that cooperates with the former to clamp the mouth of the bag.
41) Apparatus according to claim 40, wherein the support arrangement is attached to the former.
42) Apparatus according to claim 40, wherein the support arrangement is formed integrally with the former.
43) Apparatus according to any one of claims 23 to 42, wherein the seal arrangement includes a seal formed between opposing sides of the mouth of the bag using at least one of:
a) stitching;
b) a heat seal;
c) a chemical seal;
d) an adhesive; and,
e) mechanical fasteners.
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44) Apparatus according to claim 43, wherein the seal arrangement includes a folded edge that is attached to a sidewall of the bag to define a conduit extending around the mouth of the bag, the conduit including open ends, and wherein the support arrangement includes an elongate member that is threaded through the conduit and used to suspend the bag from the support structure.
45) Apparatus according to claim 44, wherein the elongate member is configured to be looped around a support structure in the mine to suspend the bag from the support structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021104702A AU2021104702A4 (en) | 2018-11-09 | 2021-07-29 | Explosion suppression method and apparatus |
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| AU2018904292A AU2018904292A0 (en) | 2018-11-09 | Explosion suppression method and apparatus |
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| AU2019101376A4 true AU2019101376A4 (en) | 2020-01-02 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112595189A (en) * | 2020-12-14 | 2021-04-02 | 安徽理工大学 | Method for preventing and treating blasting dust and blasting harmful gas |
| CN112798647A (en) * | 2020-12-25 | 2021-05-14 | 西安科技大学 | Quantitative analysis method for inhibition efficiency of explosion suppressant on gas explosion |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3140375A1 (en) * | 1981-10-10 | 1983-04-28 | Ruhrkohle Ag, 4300 Essen | UNDERGROUND EXPLOSION PROTECTION |
| DE9115075U1 (en) * | 1991-12-04 | 1992-02-06 | Schulte, Klaus, Dr., 4600 Dortmund, De | |
| DE19744155A1 (en) * | 1997-10-07 | 1999-04-08 | Lloyds Montan Produktions Und | Method for assembling explosion barriers and explosion barriers |
| DE19945108A1 (en) * | 1999-04-06 | 2000-11-02 | Lloyds Montan Gmbh | Barrier against underground gas and coal dust explosions comprises plastic bags which are suspended from beams, contain flame retarding/extinguishing substances,and are provided with a pattern of weakened zones |
| DE102005032901A1 (en) * | 2005-07-12 | 2007-01-18 | Dr. Klaus Schulte Gmbh Chemisch Technische Fabrikation | Explosion damping curtain for civil engineering has film container filled with extinguishant and wrapped around support beam with fixing strip |
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2019
- 2019-11-08 AU AU2019101376A patent/AU2019101376B4/en active Active
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112595189A (en) * | 2020-12-14 | 2021-04-02 | 安徽理工大学 | Method for preventing and treating blasting dust and blasting harmful gas |
| CN112798647A (en) * | 2020-12-25 | 2021-05-14 | 西安科技大学 | Quantitative analysis method for inhibition efficiency of explosion suppressant on gas explosion |
| CN112798647B (en) * | 2020-12-25 | 2022-09-30 | 西安科技大学 | Quantitative analysis method for inhibition efficiency of explosion suppressant on gas explosion |
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| AU2021104702A4 (en) | 2021-09-30 |
| AU2019101376B4 (en) | 2021-07-15 |
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