ZA200405231B - Explosive for rock breaking. - Google Patents
Explosive for rock breaking. Download PDFInfo
- Publication number
- ZA200405231B ZA200405231B ZA200405231A ZA200405231A ZA200405231B ZA 200405231 B ZA200405231 B ZA 200405231B ZA 200405231 A ZA200405231 A ZA 200405231A ZA 200405231 A ZA200405231 A ZA 200405231A ZA 200405231 B ZA200405231 B ZA 200405231B
- Authority
- ZA
- South Africa
- Prior art keywords
- propellant
- oxygen source
- source material
- composition according
- propellant composition
- Prior art date
Links
- 239000011435 rock Substances 0.000 title claims description 18
- 239000002360 explosive Substances 0.000 title description 11
- 239000003380 propellant Substances 0.000 claims description 91
- 239000000463 material Substances 0.000 claims description 62
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 38
- 239000001301 oxygen Substances 0.000 claims description 38
- 229910052760 oxygen Inorganic materials 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 33
- 239000002245 particle Substances 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 25
- 239000007788 liquid Substances 0.000 claims description 12
- 239000000020 Nitrocellulose Substances 0.000 claims description 10
- 229920001220 nitrocellulos Polymers 0.000 claims description 10
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 239000008187 granular material Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 239000003999 initiator Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- SNIOPGDIGTZGOP-UHFFFAOYSA-N Nitroglycerin Chemical compound [O-][N+](=O)OCC(O[N+]([O-])=O)CO[N+]([O-])=O SNIOPGDIGTZGOP-UHFFFAOYSA-N 0.000 claims description 3
- 229960003711 glyceryl trinitrate Drugs 0.000 claims description 3
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 claims 2
- 229940079938 nitrocellulose Drugs 0.000 claims 2
- 238000002485 combustion reaction Methods 0.000 description 11
- 230000008569 process Effects 0.000 description 6
- 238000005422 blasting Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000010432 diamond Substances 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000011246 composite particle Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229910003460 diamond Inorganic materials 0.000 description 2
- 239000003623 enhancer Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 241001354471 Pseudobahia Species 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000011872 intimate mixture Substances 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- -1 ore Substances 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Landscapes
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Description
’ EXPLOSIVE FOR ROCK BREAKING
. This invention relates generally to the breaking of rock and more particularly is concerned with a propellant which can be used for the breaking of rock and with a method of manufacturing a propellant of this type.
As used herein the word “rock” includes rock, ore, coal, concrete and any similar hard mass, whether above or underground, which is difficult to break or fracture. Itis to be understood that “rock” is to be interpreted broadly.
A number of techniques have been developed for the breaking of rock using non- explosive means. These include a carbon dioxide gas pressurisation method (referred to as the Cardox method), the use of gas injectors (the Sunburst technique), hydrofracturing and various methods by which cartridges containing energetic substances pressurise the walls or base of a sealed drill hole to produce penetrating cone fractures (known as PCF).
These techniques may be an order of magnitude more efficient than conventional blasting in that they require approximately 1/10 of the energy to break a given amount of rock compared to conventional blasting using high explosives. The lower energy reduces the resulting quantity of fly rock and air blast and to an extent allows the rockbreaking operation to proceed on a continuous basis as opposed to the "20 batch-type situation, which prevails with conventional blasting.
Most non-expiosive rockbreaking techniques rely on the generation of high gas pressures to initiate a tensile fracture at the bottom of a relatively short drill hole.
When the propellant is initiated, combustion products are produced. Depending on ! the combustion process the combustion products may be toxic or harmful to the health of persons in the vicinity thereof. Another factor which is to be taken into account is that incomplete or imperfect combustion may lead to a reduction in the amount of energy generated by the combustion process. Related to this aspect is the burning rate of the propellant. If the propellant burns too slowly then the rate at which energy is released is reduced and the ability of the propellant to initiate rock fracture is also reduced.
On the other hand if the propellant burns too fast then it may burn at a temperature which is so high that the propellant effectively functions as an explosive and, for safety reasons, the propellant must then be classified as an explosive. Classification in this way places severe restrictions on the storage, handling and use of the propellant. :
The invention provides a propellant composition which includes a propellant material and an oxygen source material.
The propellant composition may be in particulate form and each particle in the particulate composition may include propellant material and oxygen source material. . . 1]
Each particle may include a granule of propellant material which is coated, preferably only partly, with the oxygen source material.
- In a different form of the invention each particle is a mixture at least of the propellant i material and the oxygen source material. ' The propellant material may be of any appropriate type which is known in the art and } preferably is nitrocellulose which may be provided, as indicated, in granular form.
The oxygen source material may be of any suitable kind and for example may be ammonium nitrate.
Alternatively the propellant composition is in liquid form. A liquid has the advantage, over particulate material, that it is essentially non-compressible. Consequently, when initiated, a greater expansive force is generated than for a particular material. The liquid may include nitrocellulose as propellant and, optionally, nitro glycerine as an. enhancer. The liquid propellant may be a single, double or compound base type.
The oxygen source material may be ammonium nitrate or any similar material.
The invention also provides a method of manufacturing a propellant composition which includes the step of mixing a granular propellant material with an oxygen source material thereby to coat the propellant granules, at least partly, with a layer of oxygen source material.
The oxygen source material may be ammonium nitrate or any equivalent material.
The oxygen source material may be coated onto the propellant granules using any appropriate technique and preferably use is made of a technique which is similar to ' 20 that use for cladding diamond particles with metal as developed by companies such as De Beers Industrial Diamonds or Boart. ’
It is also possible to waterproof the propellant using any appropriate technique which, . for example, coats the propellant granules with a waterproof or water resistant film or layer. Use may for example be made of a film, eg. of nitrocellulose, which is coated onto the granules using an appropriate technique such as chemical vapour deposition. . in a different form of the invention there is provided a method of manufacturing a propellant composition which includes the step of mixing a particulate propellant material with an oxygen source material thereby to form particles wherein each particle is a mixture of the propellant and the oxygen source material.
The invention also provides rock breaking apparatus which includes a cartridge which forms an enclosure and a propellant composition of the aforementioned kind inside the enclosure.
The cartridge may be made from a malleable material which in this specification includes a material which is capable of plastic deformation, without rupturing, by at least a predetermined extent eg. of the order of 10% or more.
As used herein “propellant” includes a material such as a propellant, blasting agent, gas-evolving substance, explosive or similar means which, once initiated, generates high pressure jet material typically at least partly in gaseous form.
‘
The invention is further described by way of examples with reference to the accompanying drawings in which:
. Figure 1 schematically illustrates a method of manufacturing a propellant composition according to the invention,
Figure 2 is an enlarged cross sectional view of a particle of a propellant. composition ’ produced by the manufacturing method shown in Figure 1, , 5 Figure 3 is a view similar to Figure 2 of a different form of a propellant particle, and
Figure 4 illustrates a cartridge which makes use of a propellant composition according to the invention for breaking rock.
Figure 1 of the accompanying drawings illustrates, somewhat schematically, a method according to the invention for manufacturing a propellant composition.
Propellant particles 10 such as nitrocellulose, in granular form, are supplied to a mixer 12. The propellant particles are suitably small, for example with an effective diameter of between 0,2mm to 1mm.
An oxygen source material is held in a container 14 and is supplied at a desired rate, relatively to the supply rate of the propellant, to the mixer 12. The oxygen source material may vary according to requirement and for example is ammonium nitrate.
The oxygen source material is in liquid form.
The mixer 12 is mechanically agitated to ensure thorough mixing of the propellant with the oxygen source material. During the mixing process the various particles of » 20 the granular propellant are coated to a greater or lesser extent with the oxygen source material. This gives rise to composite particles. . .
Figure 2 illustrates in cross section a typical composite particle 16 which includes a . granular core 18 of propellant, ie. nitrocellulose, and an outer coating 20 of oxygen source material, ie. ammonium nitrate, which extends over an outer surface of the core. The coating 20 preferably does not cover the entire core 18 and leaves at least ’ a small section 22 of the core exposed. The thickness of the coating and the extent . of the coating determine the amount of oxygen source material which is available, in relation to the amount of the core propellant.
As an alternative to the aforegoing the ammonium nitrate may be coated onto the propellant particles or grains by using techniques which are analogous or similar to the techniques developed by De Beers industrial Diamonds and Boart, and other companies, for the cladding of diamond particles with metal.
The composite propeliant/oxygen source material, in granular form, is output to a cartridge filling device 26.
When a propellant such as nitrocellulose is ignited, in the absence of insufficient oxygen, the resulting combustion process gives rise to carbon monoxide, nitrates (NOs) and nitrogen dioxide. These are undesirable and toxic by-products. An object of the invention in this respect is to make available additional oxygen by means of the source material 20 to allow the combustion process to proceed more fully so that the quantity of undesirable combustion products produced by the burning process is reduced.
By increasing the quantity of available oxygen on a micro basis, ie. on a particle by ‘ particle basis, it is possible to produce combustion products such as water, carbon .
. dioxide and nitrogen which predominate over the aforementioned undesirable by- products. : It is also highly desirable to prevent the propellant from reacting with water moisture ) which may be present in the atmosphere. The propellant particles may be waterproofed using any appropriate technique although a preferred route to be followed, in this connection, is to apply a film or coating of nitrocellulose lacquer to the propellant particles using chemical vapour deposition or other appropriate techniques.
Figure 3 illustrates an alternative form of the invention wherein a composite propellant particle 30 is produced by the mixer 12 and wherein the particle includes propellant particles 32 and oxygen source material particles 34 which are held in a matrix 36. The matrix 36 may be any appropriate binder which is combustible or of an explosive nature and which is introduced from a source 38 during the mixing process. Again the intention is to bring into close proximity with each other particles of oxygen source material and propellant to ensure that when the burning process takes place adequate oxygen is available to effectively complete the combustion process.
The situation should be contrasted with what prevails when ammonium nitrate in particulate form is mixed with granular propellant. If the particles are not intimately associated with each other in the manner shown in Figure 2 or Figure 3 then the mixture is capable of separating or stratifying, depending on the transport or storage conditions, into distinct pockets of propellant and oxygen source material.
A further benefit which arises from the intimate mixture arrangements shown in .
Figures 2 and 3 is that the oxygen source material acts as a deflagratory agent, ie. burn agent, which increases the burn rate of the propellant. This increases the energy release rate which results from the burning propellant. Despite the increase in the energy release rate the ignition temperature is reduced. The propellant thus . becomes capable of exhibiting properties, from the energy release point of view, which are associated with substances normally classified as explosives. It is believed however that the propellant will still accurately be classifiable as a propellant and not as an explosive despite its enhanced properties.
In a variation of the invention the propellant composition is provided in liquid form and comprises a mixture of a liquid propellant eg. nitrocellulose, and oxygen source material in liquid form, eg. ammonium nitrate. The composition may include an enhancer, eg. nitro glycerine, and may thus be of a double base type, or have a compound base.
Figure 4 illustrates one manner in which the propellant which is produced by the method shown in Figure 1, can be used. A hole 50 is drilled into a rock mass 52 from a face 54 using conventional drilling equipment, not shown.
A cartridge 56 is loaded into the hole. The cartridge has a flat base 58 which engages closely with an end of the hole, and a generally cylindrical side wall 60.
The cartridge forms an enclosure for a propellant material 64 which is produced by the method described in connection with Figure 1 and which is loaded into the cartridge during the step 26 under factory conditions. An initiator 66, of any appropriate type, is loaded into the cartridge preferably on site.
} Control wires 68 from the initiator to a control unit, not shown, which is used in a known manner for initiating the blasting process. : Stemming 70 is placed into the hole 50 from the rock face covering the cartridge to a desired extent and is tamped in position.
The propellant 64 is ignited by the firing the initiator 66 and when this happens high pressure jet material is released as a consequence of the combustion process. The cartridge is designed to contain the expanding high pressure jet material and is allowed to deform outwardly, without rupturing, so that the cartridge is forced into sealing contact with an opposing surface of the wall of the hole 50.
The high pressure jet material is initially confined by the cartridge and the cartridge is allowed to fracture at a desired point or region which means that the force which is released by the combusting propeliant is then directed onto a chosen surface of the wall of the hole in order to fracture the rock.
The use of a propellant according to the invention in a rock breaking process of the type shown in Figure 4 means that the capability of the propellant to release energy is increased while the production of harmful by-products is reduced. As noted, if the propellant is correctly formulated, the resulting product can still accurately be classified as a propellant and not as an explosive.
As has been indicated the propellant composition can be provided in liquid form. The liquid is, for all practical purposes, incompressible and thus, when initiated, produces a pressure wave which can have a more rapidly rising leading edge than the particulate composition.
Claims (13)
1. A propellant composition which includes a propellant material and an oxygen source material. . ‘a
2. A propellant composition according to claim 1 which in particulate form and wherein each particle includes propellant material and oxygen source material.
3. A propellant composition according to claim 2 wherein each particle includes a granule of propellant material which is coated, at least partly, with the oxygen source material.
4. A propellant composition according to claim 2 wherein each particle is a mixture at least of the propellant material and the oxygen source material.
5. A propellant composition according to any one of claims 1 to 4 wherein the propellant material is nitro-cellulose.
6. A propellant composition according to any one of claims 1 to 5 wherein the oxygen source material is ammonium nitrate.
7. A propellant composition according to claim 1 which is in liquid form.
8. A propellant composition according to claim 7 wherein the liquid includes nitrocellulose and, optionally, nitro glycerine. ;
9. A method of manufacturing a propellant composition which includes the step of mixing a granular propellant material with an oxygen source material thereby to coat the propellant granules, at least partly, with a layer of oxygen source material.
10. A method according to claim 9 which includes the step of coating the propellant granules with a waterproof or water-resistant layer.
11. A method of manufacturing a propellant composition which includes the step of mixing a particulate propellant material with an oxygen source material thereby to form particles wherein each particle is a mixture of the propellant material and the oxygen source material.
12. Rock breaking apparatus which includes a cartridge which forms an enclosure and a propellant composition according to any one of claims 1 to 8 inside the enclosure,
13. Rock breaking apparatus according to claim 12 wherein the cartridge is made from a malleable material and includes a cylindrical side wall and a base, and wherein an initiator is located in the propellant composition inside the cartridge.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA200405231A ZA200405231B (en) | 2002-01-03 | 2004-07-01 | Explosive for rock breaking. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA200105468 | 2002-01-03 | ||
| ZA200405231A ZA200405231B (en) | 2002-01-03 | 2004-07-01 | Explosive for rock breaking. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| ZA200405231B true ZA200405231B (en) | 2005-06-03 |
Family
ID=35160986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| ZA200405231A ZA200405231B (en) | 2002-01-03 | 2004-07-01 | Explosive for rock breaking. |
Country Status (1)
| Country | Link |
|---|---|
| ZA (1) | ZA200405231B (en) |
-
2004
- 2004-07-01 ZA ZA200405231A patent/ZA200405231B/en unknown
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