CA2136572A1 - Explosive - Google Patents
ExplosiveInfo
- Publication number
- CA2136572A1 CA2136572A1 CA002136572A CA2136572A CA2136572A1 CA 2136572 A1 CA2136572 A1 CA 2136572A1 CA 002136572 A CA002136572 A CA 002136572A CA 2136572 A CA2136572 A CA 2136572A CA 2136572 A1 CA2136572 A1 CA 2136572A1
- Authority
- CA
- Canada
- Prior art keywords
- conduit
- explosive
- pump
- base
- lubricant liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B47/00—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase
- C06B47/14—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase comprising a solid component and an aqueous phase
- C06B47/145—Water in oil emulsion type explosives in which a carbonaceous fuel forms the continuous phase
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
Abstract
The invention provides a method of making a sensitized flowable explosive by pumping a non-detonatable explosive base along a conduit having a mixer at its downstream end. Simultaneously lubricant liquid is pumped along the conduit while a flowable gassing agent is pumped along a separate flow line into the conduit, adjacent and upstream of the mixing device, where mixing of the constituents takes place to form a sensitized explosive. The invention also provides an apparatus (10) comprising an explosive base pump (22) connected to a conduit (46) provided witha mixer at its downstream end, a flowable gassing agent pump (28) and a lubricant liquid pump (30). The lubricant liquid pump (30) feeds into the conduit (46), and the gassing agent pump (28) feeds into a separate flow line (50) connected to the conduit (46) at the downstream end of the conduit upstream of the mixing device.
Description
21~6572 THIS INVENTION relates, broadly, to an explosive. More particularly the invention relates to a method and apparatus suitable for m~king a flowable explosive, in particular an emulsion explosive.
According to the invention there is provided a method of m~king a sensitized flowable explosive, the method comprising the steps of:
pumping a non-detonatable explosive base from a supply of said base by means of an explosive base pump along a conduit having a mixing device at or adjacent a downstream end thereof;
simultanéously pumping a lubricant liquid from a supply of said lubricant 0 liquid along the conduit by means of a lubricant pump;
simultaneously pumping a flowable gassing agent for gassing the base from a supply of said gassing agent by means of a gassing agent pump along a separateflow line into the conduit, upstream of and at or adjacent the mixing device; and mixing the base and lubricant liquid together with the gassing agent in the 5 mixing device to form a sensitized explosive.
Examples of flowable explosives of the type in question are slurry explosives and emulsion explosives having respectively a slurry or emulsion base, so that the mixing results in a sensitized slurry or emulsion explosive, as the case may be.
The pumping of the gassing agent into the conduit will preferably be at a 20 position as close as possible to or imrnediately upstream of the mixing device. In particular, the mixing device may be at the downstream end of the conduit, the pumping of the gassing agent into the conduit being at a position immediately upstream of the mixing device.
-The gassing agent may be a chemical gassing solution such as a solution having a solvent which comprises water and a solute which comprises nitrite ions.
A sodium nitrite solution will usually be employed, the base and/or lubricant liquid containing ammonium ions so that the explosive is sensitized by chemical gassing5 caused by the formation of nitrogen bubbles in the base in accordance with the reaction:
NH 4 + NO 2 ~ 2H2O + N2 Each pump may be a reciprocable positive displacement dosing pump and the pumps may be interconnected or otherwise synchronised with one another to deliver 10 accurately matched outputs. In other words, pumping of the explosive base, pumping of the lubricarit liquid and pumping of the gassing agent may be by means of reciprocable positive displacement dosing pumps which are synchronized with one another to deliver accurately matched outputs. The lubricant liquid will typically be fed into the conduit at or adjacent the point of feed of the base into the conduit, so 15 that the lubricant liquid forms an annular lubricating layer around the base as they pass along the conduit. In particular, the explosive base and the lubricant liquid may be pumped into the conduit at the same position, the lubricant liquid and explosive base being pumped into the conduit so that they pass simultaneously along the conduit with the lubricant liquid forming an annular lubricating layer around a core 20 of explosive base, between the core and the conduit.The lubricant may comprise water and/or a suitable organic liquid for forming a fuel in the eventual sensitized explosive, such as a glycol, having a suitably low viscosity; and it may comprise ammonium ions. More particularly, the lubricant liquid may be selected from water, ethylene glycol, diethylene glycol and mixtures thereof.
The conduit and the flow line may comprise flexible hoses, suitable for loading an explosive into boreholes, the conduit usually comprising a lance at its downstream end and the mixing device being mounted in the downstream end of the lance. The hoses may be strapped together so that they extend side-by-side in use.
2136~72 ~_ 3 An important advantage of the method is that, when the method has been used for eg loading sensitized explosive into boreholes and is discontinued, only themixing device and such parts of the conduit (hose or lance), if any, as are downstream of the mixing device need contain sensitized explosive. Danger is 5 reduced; and the need to discard this sensitized explosive, eg when the method has been discontinued for a period long enough for this sensitized explosive to become unsuitable for use, results in loss of relatively small amounts, if any, of explosive.
A further advantage of the invention is that the rate of gassing of the base canbe increased and mixing can be carried out at relatively low pressures with a 10 relatively accurately controlled rate of gassing of the base. Furthermore, as the gassing solutior; is not used for lubrication, relatively small amounts of water in the gassing solution can be employed.
Further according to the invention there is provided an apparatus for m~king a sensitized explosive, the apparatus comprising:
an explosive base pump having an inlet for explosive base emulsion and an outlet which is connected to a conduit;
a mixing device connected in line with the conduit at or adjacent a downstream end thereof;
a flowable gassing agent pump having an inlet for a flowable gassing agent 20 and an outlet which is connected to a separate flow line, the separate flow line having a downstream end which is connected to the conduit at or adjacent and upstream of the mixing device; and a lubricant liquid pump having an inlet for a lubricant liquid and an outlet which is connected to the conduit, 25 the explosive base pump and the lubricant liquid pump having their outlets connected to the conduit at positions which are at or adjacent each other.
21~6572 `_ 4 The pumps may be operatively interconnected or otherwise synchronised as described above, and may be positive displacement dosing pumps. In particular, the explosive base pump, the lubricant pump and the gassing agent pump may be positive displacement dosing pumps which are operatively interconnected to one S another for synchronous use in the delivery of matched outputs.
The apparatus may include:
a supply of explosive base connected to the inlet of the base pump;
a supply of gassing agent connected to the inlet of the gassing agent pump;
and 10a supply of lubricant liquid connected to the inlet of the lubricant liquid pump.
The conduit and the separate flow line may each be a flexible hose or pipe, and the conduit may comprise a lance at its downstream end for loading sensitized explosive into boreholes, the mixing device, which may be a rotary mixer, staticmixer or the like, being associated with the lance, and being mounted eg at the free 15 or downstream end thereof, in line therewith. In a particular embodiment, theconduit and separate flow line may each comprise a flexible hose, the flexible hose of the conduit having a downstream end connected to an inlet of a lance for loading sensitized explosive into boreholes, the mixing device being mounted on the lance.
The hoses may be strapped together, eg at spaced intervals along their lengths, 20 so that, in use, they extend alongside each other. In particular, the hoses may be connected to each other at a plurality of positions spaced along their lengths so that they extend alongside each other, the mixing device being selected from rotary mixers and static mixers and the lance having a downstream end, at or adjacent which the mixing device is mounted.
25While the apparatus may be fixed in place, so that it forms part of an installation, it will typically be portable by no more than two persons, the apparatus comprising a support frame on which the pumps are mounted, the support frame being provided with a pair of carry handles and a motor, the motor being mountedon the support frame and being operatively interconnected to the pumps for simultaneously driving the pumps.
S The motor may be an air motor drivable by a compressed air supply, the support frame being in the form of a sled having a pair of runners for engaging the ground with the frame in an upright operative attitude.
The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
Figure l'shows a schematic side elevation of an apparatus in accordance with the invention; and Figure 2 shows a schematic plan view of the apparatus of Figure 1.
In the drawings, reference numeral 10 generally an apparatus in accordance with the present invention. The apparatus 10 is portable by two persons and comprises an elongated support frame 12 of metal tubing providing pairs of carryhandles 14 at opposite ends thereof. The support frame is in the form of a sled having a pair of runners 15 on which it can be pushed and pulled along the ground.
An emulsion base supply in the form of a tank 16 is mounted on the frame 12, as are a gassing agent supply in the form of a tank 18, and a lubricant liquid supply in the form of a tank 20. The tank 20 is omitted from and is not illustrated in Figure 1, for clarity of illustration.
A reciprocable piston and cylinder type positive displacement base pump 22 is shown having an inlet connected to the tank 16, an outlet provided with a non-return valve 24, and an air motor 26 drivingly connected thereto, all being mounted directly or indirectly on the frame 12. The pump has, mounted on opposite sides thereof and operatively connected alongside it for simultaneous synchronous operation, a gassing agent pump 28 and a lubricant liquid pump 30, having respective piston rods 32 and 34 connected by respective links 36 and 38 to a piston 40 of the pump 22.
The tank 18 is connected by a flexible hose 42 to an inlet to the pump 28; and S the tank 20 is connected by a flexible hose 44 (not shown in Figure 1) to an inlet to the pump 30. The valve 24 in turn feeds into a conduit in the form of a flexible hose 46; and the pump 30 has an outlet feeding via a flexible hose 48 into the hose 46, immediately downstream of and adjacent the valve 24, the pump 28 having an outlet feeding via a flexible hose 50 which extends alongside the hose 46 and is strapped 10 thereto by straps 52 spaced along the length of the hose 46.
The downstream end of the hose 46 is provided with a lance (not shown) having a rotary or static mixer (also not shown) at its downstream end. The hose 46 feeds into the lance and into the mixer, and the hose 50 extends alongside the lance up to the mixer, into which it feeds, the mixer in turn feeding into the outlet Or the 15 lance at the tip of the lance.
In use, the apparatus 10 will typically be taken to a blasting site, for exampleunder ground in a mine. The apparatus can conveniently be carried by two personsby means of a handle 14, with the hose 46 and associated lance coiled on the frame 12, and the tanks 16, 18, 20 cont~inin~ the necessary constituents.
Usually the apparatus will be used in accordance with the method of the present invention to make a sensitized emulsion explosive of the water-in-oil type, which comprises an oil-based continuous phase and a water-based discontinuous phase dispersed in the continuous phase.
In this type of system, the tank 16 will contain an emulsion base, and the tank 18 will contain an aqueous sodium nitrite gassing solution. The tank 20 will in turn ~136572 contain a lubricant liquid, for example a suitable water/ethylene glycol mixturecontaining ammonium ions and a gassing reaction catalyst such as a thiourea, together with pH-controlling additives and the like.
At a blasting site, the motor 26 is used synchronously to drive the pumps 22, 28 and 30. Pump 22 pumps emulsion base from the tank 16 into the upstream end of the hose 46 via the non-return valve 24; and pump 30 pumps lubricant liquid which it receives via the hose 44 from the tank 20, into the hose 46 via the hose 48, at the upstream end of the hose 46, immediately adjacent and downstream of the valve 24. Emulsion base flows along the hose 46, and its passage along the hose 46 is lubricated by an annular layer of the lubricant liquid which surrounds it, and eases its travel along ~he hose 46. The pump 28 receives gassing solution via the hose 42 from the tank 18, and pumps it long the hose 50. It should be noted in this regard with reference to the aforegoing that the gassing solution can contain a proportion of ethylene glycol, the ethylene glycol in the gassing solution and lubricant liquid being water-miscible and capable of acting as a fuel, although other water-miscible fuels may be used instead of the ethylene glycol.
At the downstream end of the hose 46, the hose 46 and hose 50 respectively feed into the inlet of the mixer in the lance, where the lubricant liquid, emulsion base and gassing solution are thoroughly and homogeneously mixed together, to form anemulsion explosive.
It should be noted that rapid mixing is permitted between the lubricant liquid and gassing solution before they become finally incorporated into the emulsion explosive, thereby permitting thorough reaction of the nitrite ions in the gassing solution with the ammonium ions in the lubricant liquid, for effective and reliable nitrogen bubble formation.
213657~
-It should be noted in particular, that, in a variation of the method of the invention, the lubricant liquid can be introduced into the hose 46, or the lance, somewhat upstream of the mlxer. In this way, the lubricant liquid and gassing solution, which are readily miscible liqulds, can be given the opportunity to mix S homogeneously together, to initiate gassing and to bring said ammonium ions into contact with said nitrite ions, before the lubricant liquid and gassing solution are emulsified into the emulsion base in the mixer, thereby further promoting efficient and reliable gassing of the emulsion explosive.
In this regard it is to be noted that sensitizing water-in-oil emulsion 10 explosives by chemical gassing is problematic when a gassing solution is simply mixed into an émulsion base cont~ining ammonium ions, as the rate of gassing reaction is dependent on a number of chemical factors and other factors such as pH, temperature, time and concentration of catalyst, but in particular, the mixing efficiency may be rate-determining factor of the gassing reaction. This is because, 15 on addition of the gassing solution to the water-in-oil emulsion base, discrete droplets of gassing solution can be formed within the continuous oil phase of the emulsion base. As the ammonium ions in this case are typically contained in the discontinuous water phase of the emulsion base, for these ammonium ions and the nitrite ions of the gassing solution to come into contact with one another, ion transport across20 emulsion oil phase/water phase bilayers is necessitated. As the continuous phase is oil-based, transport by diffusion of the water-soluble ions in question is relatively slow and can become rate-deterrnining.
It is a particular advantage of the present invention that it can elimin~te thisrate-determining limitation, by providing the ammonium ions in the lubricant solution 25 and ensuring that the lubricant solution and gassing solution, come into contact with each other and are at least partially admixed with each other before or at least no later than when they are mixed into the emulsion base. Rapid mixing thereof takes place as the lubricant liquid and gassing solution are easily miscible aqueous solutions, and effective and reliable nitrogen bubble and gasification are promoted, at least partially prior to isolation of the amrnonium and nitrite ions in separate droplets separated from one another by the oil phase of the emulsion. The rate of the gassing reaction is therefor controlled by temperature and chemical factors, and 5 ion diffusion is no longer rate-controlling.
With regard to the aforegoing, it should be noted that the roles of the gassing solution and lubricant liquid can be reversed, in the sense that, if desired, the solution cont~ining the nitrite ions may be contained in the tank 20 and pumped by the pump 30; with the solution cont~ining the ammonium ions being contained in 10 the tank 18 and pumped by the pump 28. This latter possibility will, however,usually not be preferred, as the emulsion base typically contains ammonium ions, so that some gassing can take place along the whole length of the hose 46, which isundesirable, as it can necessitate discarding the contents of the hose 46 after loading a borehole has been continued, and before loading a further borehole is initiated.
15 This reversal of roles is however feasible if the emulsion base contains no ammonium ions, and in this case the nitrite ion-cont:~ining solution will in fact act as a lubricant solution and the ammonium ion-cont~ining solution will in fact act as a gassing solution.
Comparative Tests Comparative tests were carried out whereby the method and apparatus of the present invention were compared in use with a standard gassing method and apparatus, using the same emulsion base which was prepared at 10C, the same lubricant liquid and the same flowable gassing agent. The present invention resulted in the production, after 20 mimltes, of a sensitized emulsion explosive product having a density of 1,10 g/cm3, whereas the standard gassing system produced a product having a final density of 1,18 g/cm3 after 60 minutes.
2t36572 In a further test, using a high crystallized emulsion base, it was found that the abovementioned standard gassing system resulted in hardly any gassing of the base, whereas the method and apparatus of the present invention were found to be capable, on this highly crystallized emulsion base, of achieving a final density of 1,15 g/cm3 after 25 minutes.
Comparative tests on a further emulsion base, having a starting density of 1,52 g/cm3, resulted in a final density of 1,25 g/cm3 using the standard gassing system, and a final density of 1,18 g/cm3 using the method and apparatus of the present invention.
Finally, the standard (control) system was found to be incapable of gassing an emulsion base having a pH > 3,6, but it was found that this emulsion base could be gassed to a final density of 1,18 g/cm3 after 25 minlltes, using the method and apparatus of the present invention.
The above tests illustrate that, when the method and apparatus of the present invention are used, the gassing rate is less dependent on the properties of the emulsion than is the case with the standard gassing system tested as a control, and the gassing was found to be more easily and accurately controllable than with the standard system, when using the method and apparatus of the present invention.
According to the invention there is provided a method of m~king a sensitized flowable explosive, the method comprising the steps of:
pumping a non-detonatable explosive base from a supply of said base by means of an explosive base pump along a conduit having a mixing device at or adjacent a downstream end thereof;
simultanéously pumping a lubricant liquid from a supply of said lubricant 0 liquid along the conduit by means of a lubricant pump;
simultaneously pumping a flowable gassing agent for gassing the base from a supply of said gassing agent by means of a gassing agent pump along a separateflow line into the conduit, upstream of and at or adjacent the mixing device; and mixing the base and lubricant liquid together with the gassing agent in the 5 mixing device to form a sensitized explosive.
Examples of flowable explosives of the type in question are slurry explosives and emulsion explosives having respectively a slurry or emulsion base, so that the mixing results in a sensitized slurry or emulsion explosive, as the case may be.
The pumping of the gassing agent into the conduit will preferably be at a 20 position as close as possible to or imrnediately upstream of the mixing device. In particular, the mixing device may be at the downstream end of the conduit, the pumping of the gassing agent into the conduit being at a position immediately upstream of the mixing device.
-The gassing agent may be a chemical gassing solution such as a solution having a solvent which comprises water and a solute which comprises nitrite ions.
A sodium nitrite solution will usually be employed, the base and/or lubricant liquid containing ammonium ions so that the explosive is sensitized by chemical gassing5 caused by the formation of nitrogen bubbles in the base in accordance with the reaction:
NH 4 + NO 2 ~ 2H2O + N2 Each pump may be a reciprocable positive displacement dosing pump and the pumps may be interconnected or otherwise synchronised with one another to deliver 10 accurately matched outputs. In other words, pumping of the explosive base, pumping of the lubricarit liquid and pumping of the gassing agent may be by means of reciprocable positive displacement dosing pumps which are synchronized with one another to deliver accurately matched outputs. The lubricant liquid will typically be fed into the conduit at or adjacent the point of feed of the base into the conduit, so 15 that the lubricant liquid forms an annular lubricating layer around the base as they pass along the conduit. In particular, the explosive base and the lubricant liquid may be pumped into the conduit at the same position, the lubricant liquid and explosive base being pumped into the conduit so that they pass simultaneously along the conduit with the lubricant liquid forming an annular lubricating layer around a core 20 of explosive base, between the core and the conduit.The lubricant may comprise water and/or a suitable organic liquid for forming a fuel in the eventual sensitized explosive, such as a glycol, having a suitably low viscosity; and it may comprise ammonium ions. More particularly, the lubricant liquid may be selected from water, ethylene glycol, diethylene glycol and mixtures thereof.
The conduit and the flow line may comprise flexible hoses, suitable for loading an explosive into boreholes, the conduit usually comprising a lance at its downstream end and the mixing device being mounted in the downstream end of the lance. The hoses may be strapped together so that they extend side-by-side in use.
2136~72 ~_ 3 An important advantage of the method is that, when the method has been used for eg loading sensitized explosive into boreholes and is discontinued, only themixing device and such parts of the conduit (hose or lance), if any, as are downstream of the mixing device need contain sensitized explosive. Danger is 5 reduced; and the need to discard this sensitized explosive, eg when the method has been discontinued for a period long enough for this sensitized explosive to become unsuitable for use, results in loss of relatively small amounts, if any, of explosive.
A further advantage of the invention is that the rate of gassing of the base canbe increased and mixing can be carried out at relatively low pressures with a 10 relatively accurately controlled rate of gassing of the base. Furthermore, as the gassing solutior; is not used for lubrication, relatively small amounts of water in the gassing solution can be employed.
Further according to the invention there is provided an apparatus for m~king a sensitized explosive, the apparatus comprising:
an explosive base pump having an inlet for explosive base emulsion and an outlet which is connected to a conduit;
a mixing device connected in line with the conduit at or adjacent a downstream end thereof;
a flowable gassing agent pump having an inlet for a flowable gassing agent 20 and an outlet which is connected to a separate flow line, the separate flow line having a downstream end which is connected to the conduit at or adjacent and upstream of the mixing device; and a lubricant liquid pump having an inlet for a lubricant liquid and an outlet which is connected to the conduit, 25 the explosive base pump and the lubricant liquid pump having their outlets connected to the conduit at positions which are at or adjacent each other.
21~6572 `_ 4 The pumps may be operatively interconnected or otherwise synchronised as described above, and may be positive displacement dosing pumps. In particular, the explosive base pump, the lubricant pump and the gassing agent pump may be positive displacement dosing pumps which are operatively interconnected to one S another for synchronous use in the delivery of matched outputs.
The apparatus may include:
a supply of explosive base connected to the inlet of the base pump;
a supply of gassing agent connected to the inlet of the gassing agent pump;
and 10a supply of lubricant liquid connected to the inlet of the lubricant liquid pump.
The conduit and the separate flow line may each be a flexible hose or pipe, and the conduit may comprise a lance at its downstream end for loading sensitized explosive into boreholes, the mixing device, which may be a rotary mixer, staticmixer or the like, being associated with the lance, and being mounted eg at the free 15 or downstream end thereof, in line therewith. In a particular embodiment, theconduit and separate flow line may each comprise a flexible hose, the flexible hose of the conduit having a downstream end connected to an inlet of a lance for loading sensitized explosive into boreholes, the mixing device being mounted on the lance.
The hoses may be strapped together, eg at spaced intervals along their lengths, 20 so that, in use, they extend alongside each other. In particular, the hoses may be connected to each other at a plurality of positions spaced along their lengths so that they extend alongside each other, the mixing device being selected from rotary mixers and static mixers and the lance having a downstream end, at or adjacent which the mixing device is mounted.
25While the apparatus may be fixed in place, so that it forms part of an installation, it will typically be portable by no more than two persons, the apparatus comprising a support frame on which the pumps are mounted, the support frame being provided with a pair of carry handles and a motor, the motor being mountedon the support frame and being operatively interconnected to the pumps for simultaneously driving the pumps.
S The motor may be an air motor drivable by a compressed air supply, the support frame being in the form of a sled having a pair of runners for engaging the ground with the frame in an upright operative attitude.
The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
Figure l'shows a schematic side elevation of an apparatus in accordance with the invention; and Figure 2 shows a schematic plan view of the apparatus of Figure 1.
In the drawings, reference numeral 10 generally an apparatus in accordance with the present invention. The apparatus 10 is portable by two persons and comprises an elongated support frame 12 of metal tubing providing pairs of carryhandles 14 at opposite ends thereof. The support frame is in the form of a sled having a pair of runners 15 on which it can be pushed and pulled along the ground.
An emulsion base supply in the form of a tank 16 is mounted on the frame 12, as are a gassing agent supply in the form of a tank 18, and a lubricant liquid supply in the form of a tank 20. The tank 20 is omitted from and is not illustrated in Figure 1, for clarity of illustration.
A reciprocable piston and cylinder type positive displacement base pump 22 is shown having an inlet connected to the tank 16, an outlet provided with a non-return valve 24, and an air motor 26 drivingly connected thereto, all being mounted directly or indirectly on the frame 12. The pump has, mounted on opposite sides thereof and operatively connected alongside it for simultaneous synchronous operation, a gassing agent pump 28 and a lubricant liquid pump 30, having respective piston rods 32 and 34 connected by respective links 36 and 38 to a piston 40 of the pump 22.
The tank 18 is connected by a flexible hose 42 to an inlet to the pump 28; and S the tank 20 is connected by a flexible hose 44 (not shown in Figure 1) to an inlet to the pump 30. The valve 24 in turn feeds into a conduit in the form of a flexible hose 46; and the pump 30 has an outlet feeding via a flexible hose 48 into the hose 46, immediately downstream of and adjacent the valve 24, the pump 28 having an outlet feeding via a flexible hose 50 which extends alongside the hose 46 and is strapped 10 thereto by straps 52 spaced along the length of the hose 46.
The downstream end of the hose 46 is provided with a lance (not shown) having a rotary or static mixer (also not shown) at its downstream end. The hose 46 feeds into the lance and into the mixer, and the hose 50 extends alongside the lance up to the mixer, into which it feeds, the mixer in turn feeding into the outlet Or the 15 lance at the tip of the lance.
In use, the apparatus 10 will typically be taken to a blasting site, for exampleunder ground in a mine. The apparatus can conveniently be carried by two personsby means of a handle 14, with the hose 46 and associated lance coiled on the frame 12, and the tanks 16, 18, 20 cont~inin~ the necessary constituents.
Usually the apparatus will be used in accordance with the method of the present invention to make a sensitized emulsion explosive of the water-in-oil type, which comprises an oil-based continuous phase and a water-based discontinuous phase dispersed in the continuous phase.
In this type of system, the tank 16 will contain an emulsion base, and the tank 18 will contain an aqueous sodium nitrite gassing solution. The tank 20 will in turn ~136572 contain a lubricant liquid, for example a suitable water/ethylene glycol mixturecontaining ammonium ions and a gassing reaction catalyst such as a thiourea, together with pH-controlling additives and the like.
At a blasting site, the motor 26 is used synchronously to drive the pumps 22, 28 and 30. Pump 22 pumps emulsion base from the tank 16 into the upstream end of the hose 46 via the non-return valve 24; and pump 30 pumps lubricant liquid which it receives via the hose 44 from the tank 20, into the hose 46 via the hose 48, at the upstream end of the hose 46, immediately adjacent and downstream of the valve 24. Emulsion base flows along the hose 46, and its passage along the hose 46 is lubricated by an annular layer of the lubricant liquid which surrounds it, and eases its travel along ~he hose 46. The pump 28 receives gassing solution via the hose 42 from the tank 18, and pumps it long the hose 50. It should be noted in this regard with reference to the aforegoing that the gassing solution can contain a proportion of ethylene glycol, the ethylene glycol in the gassing solution and lubricant liquid being water-miscible and capable of acting as a fuel, although other water-miscible fuels may be used instead of the ethylene glycol.
At the downstream end of the hose 46, the hose 46 and hose 50 respectively feed into the inlet of the mixer in the lance, where the lubricant liquid, emulsion base and gassing solution are thoroughly and homogeneously mixed together, to form anemulsion explosive.
It should be noted that rapid mixing is permitted between the lubricant liquid and gassing solution before they become finally incorporated into the emulsion explosive, thereby permitting thorough reaction of the nitrite ions in the gassing solution with the ammonium ions in the lubricant liquid, for effective and reliable nitrogen bubble formation.
213657~
-It should be noted in particular, that, in a variation of the method of the invention, the lubricant liquid can be introduced into the hose 46, or the lance, somewhat upstream of the mlxer. In this way, the lubricant liquid and gassing solution, which are readily miscible liqulds, can be given the opportunity to mix S homogeneously together, to initiate gassing and to bring said ammonium ions into contact with said nitrite ions, before the lubricant liquid and gassing solution are emulsified into the emulsion base in the mixer, thereby further promoting efficient and reliable gassing of the emulsion explosive.
In this regard it is to be noted that sensitizing water-in-oil emulsion 10 explosives by chemical gassing is problematic when a gassing solution is simply mixed into an émulsion base cont~ining ammonium ions, as the rate of gassing reaction is dependent on a number of chemical factors and other factors such as pH, temperature, time and concentration of catalyst, but in particular, the mixing efficiency may be rate-determining factor of the gassing reaction. This is because, 15 on addition of the gassing solution to the water-in-oil emulsion base, discrete droplets of gassing solution can be formed within the continuous oil phase of the emulsion base. As the ammonium ions in this case are typically contained in the discontinuous water phase of the emulsion base, for these ammonium ions and the nitrite ions of the gassing solution to come into contact with one another, ion transport across20 emulsion oil phase/water phase bilayers is necessitated. As the continuous phase is oil-based, transport by diffusion of the water-soluble ions in question is relatively slow and can become rate-deterrnining.
It is a particular advantage of the present invention that it can elimin~te thisrate-determining limitation, by providing the ammonium ions in the lubricant solution 25 and ensuring that the lubricant solution and gassing solution, come into contact with each other and are at least partially admixed with each other before or at least no later than when they are mixed into the emulsion base. Rapid mixing thereof takes place as the lubricant liquid and gassing solution are easily miscible aqueous solutions, and effective and reliable nitrogen bubble and gasification are promoted, at least partially prior to isolation of the amrnonium and nitrite ions in separate droplets separated from one another by the oil phase of the emulsion. The rate of the gassing reaction is therefor controlled by temperature and chemical factors, and 5 ion diffusion is no longer rate-controlling.
With regard to the aforegoing, it should be noted that the roles of the gassing solution and lubricant liquid can be reversed, in the sense that, if desired, the solution cont~ining the nitrite ions may be contained in the tank 20 and pumped by the pump 30; with the solution cont~ining the ammonium ions being contained in 10 the tank 18 and pumped by the pump 28. This latter possibility will, however,usually not be preferred, as the emulsion base typically contains ammonium ions, so that some gassing can take place along the whole length of the hose 46, which isundesirable, as it can necessitate discarding the contents of the hose 46 after loading a borehole has been continued, and before loading a further borehole is initiated.
15 This reversal of roles is however feasible if the emulsion base contains no ammonium ions, and in this case the nitrite ion-cont:~ining solution will in fact act as a lubricant solution and the ammonium ion-cont~ining solution will in fact act as a gassing solution.
Comparative Tests Comparative tests were carried out whereby the method and apparatus of the present invention were compared in use with a standard gassing method and apparatus, using the same emulsion base which was prepared at 10C, the same lubricant liquid and the same flowable gassing agent. The present invention resulted in the production, after 20 mimltes, of a sensitized emulsion explosive product having a density of 1,10 g/cm3, whereas the standard gassing system produced a product having a final density of 1,18 g/cm3 after 60 minutes.
2t36572 In a further test, using a high crystallized emulsion base, it was found that the abovementioned standard gassing system resulted in hardly any gassing of the base, whereas the method and apparatus of the present invention were found to be capable, on this highly crystallized emulsion base, of achieving a final density of 1,15 g/cm3 after 25 minutes.
Comparative tests on a further emulsion base, having a starting density of 1,52 g/cm3, resulted in a final density of 1,25 g/cm3 using the standard gassing system, and a final density of 1,18 g/cm3 using the method and apparatus of the present invention.
Finally, the standard (control) system was found to be incapable of gassing an emulsion base having a pH > 3,6, but it was found that this emulsion base could be gassed to a final density of 1,18 g/cm3 after 25 minlltes, using the method and apparatus of the present invention.
The above tests illustrate that, when the method and apparatus of the present invention are used, the gassing rate is less dependent on the properties of the emulsion than is the case with the standard gassing system tested as a control, and the gassing was found to be more easily and accurately controllable than with the standard system, when using the method and apparatus of the present invention.
Claims (17)
1. A method of making a sensitized flowable explosive, the method comprising the steps of:
pumping a non-detonatable explosive base from a supply of said base by means of an explosive base pump along a conduit having a mixing device at or adjacent a downstream end thereof;
simultaneously pumping a lubricant liquid from a supply of said lubricant liquid along the conduit by means of a lubricant pump;
simultaneously pumping a flowable gassing agent for gassing the base from a supply of said gassing agent by means of a gassing agent pump along a separateflow line into the conduit, upstream of and at or adjacent the mixing device; and mixing the base and lubricant liquid together with the gassing agent in the mixing device to form a sensitized explosive.
pumping a non-detonatable explosive base from a supply of said base by means of an explosive base pump along a conduit having a mixing device at or adjacent a downstream end thereof;
simultaneously pumping a lubricant liquid from a supply of said lubricant liquid along the conduit by means of a lubricant pump;
simultaneously pumping a flowable gassing agent for gassing the base from a supply of said gassing agent by means of a gassing agent pump along a separateflow line into the conduit, upstream of and at or adjacent the mixing device; and mixing the base and lubricant liquid together with the gassing agent in the mixing device to form a sensitized explosive.
2. A method as claimed in claim 1, in which the explosive base is an emulsion base, so that the mixing results in the formation of a sensitized emulsion explosive.
3. A method as claimed in claim 1 or claim 2, in which the mixing device is at the downstream end of the conduit, the pumping of the gassing agent into the conduit being at a position immediately upstream of the mixing device.
4. A method as claimed in any one of the preceding claims, in which the gassing agent is a chemical gassing solution.
5. A method as claimed in claim 4, in which the chemical gassing solution has a solvent which comprises water and a solute which comprises nitrite ions.
6. A method as claimed in any one of the preceding claims, in which pumping of the explosive base, pumping of the lubricant liquid and pumping of the gassing agent are by means of reciprocable positive displacement dosing pumps which are synchronized with one another to deliver accurately matched outputs.
7. A method as claimed in any one of the preceding claims, in which the explosive base and the lubricant liquid are pumped into the conduit at the same position, the lubricant liquid and explosive base being pumped into the conduit so that they pass simultaneously along the conduit with the lubricant liquid forming an annular lubricating layer around a core of explosive base, between the core and the conduit.
8. A method as claimed in any one of the preceding claims, in which the lubricant liquid is selected from water, ethylene glycol, diethylene glycol and mixtures thereof.
9. A method as claimed in claim 1, substantially as described and as illustratedherein with reference to the drawings.
10. An apparatus for making a sensitized explosive, the apparatus comprising:
an explosive base pump having an inlet for explosive base emulsion and an outlet which is connected to a conduit;
a mixing device connected in line with the conduit at or adjacent a downstream end thereof;
a flowable gassing agent pump having an inlet for a flowable gassing agent and an outlet which is connected to a separate flow line, the separate flow linehaving a downstream end which is connected to the conduit at or adjacent and upstream of the mixing device; and a lubricant liquid pump having an inlet for a lubricant liquid and an outlet which is connected to the conduit, the explosive base pump and the lubricant liquid pump having their outlets connected to the conduit at positions which are at or adjacent each other.
an explosive base pump having an inlet for explosive base emulsion and an outlet which is connected to a conduit;
a mixing device connected in line with the conduit at or adjacent a downstream end thereof;
a flowable gassing agent pump having an inlet for a flowable gassing agent and an outlet which is connected to a separate flow line, the separate flow linehaving a downstream end which is connected to the conduit at or adjacent and upstream of the mixing device; and a lubricant liquid pump having an inlet for a lubricant liquid and an outlet which is connected to the conduit, the explosive base pump and the lubricant liquid pump having their outlets connected to the conduit at positions which are at or adjacent each other.
11. An apparatus as claimed in claim 10, in which the explosive base pump, the gassing agent pump and the lubricant liquid pump are positive displacement dosing pumps which are operatively interconnected to one another for synchronous use inthe delivery of matched outputs.
12. An apparatus as claimed in claim 10 or claim 11, which includes:
a supply of explosive base connected to the inlet of the base pump;
a supply of gassing agent connected to the inlet of the gassing agent pump;
and a supply of lubricant liquid connected to the inlet of the lubricant liquid pump.
a supply of explosive base connected to the inlet of the base pump;
a supply of gassing agent connected to the inlet of the gassing agent pump;
and a supply of lubricant liquid connected to the inlet of the lubricant liquid pump.
13. An apparatus as claimed in any one of claims 10 - 12 inclusive, in which theconduit and separate flow line each comprise a flexible hose, the flexible hose of the conduit having a downstream end connected to an inlet of a lance for loading sensitized explosive into boreholes, the mixing device being mounted on the lance.
14. An apparatus as claimed in claim 13, in which the hoses are connected to each other at a plurality of positions spaced along their lengths so that they extendalongside each other, the mixing device being selected from rotary mixers and static mixers and the lance having a downstream end, at or adjacent which the mixing device is mounted.
15. An apparatus as claimed in any one of claims 10 - 14 inclusive, which is portable by no more than two persons, the apparatus comprising a support frame on which the pumps are mounted, the support frame being provided with a pair of carry handles and a motor, the motor being mounted on the support frame and being operatively interconnected to the pumps for simultaneously driving the pumps.
16. An apparatus as claimed in claim 15, in which the motor is an air motor drivable by a compressed air supply, the support frame being in the form of a sled having a pair of runners for engaging the ground with the frame in an upright operative attitude.
17. An apparatus as claimed in claim 10, substantially as described and as illustrated herein with reference to the drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA93/8860 | 1993-11-26 | ||
| ZA938860 | 1993-11-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2136572A1 true CA2136572A1 (en) | 1995-05-27 |
Family
ID=25583462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002136572A Abandoned CA2136572A1 (en) | 1993-11-26 | 1994-11-24 | Explosive |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN1065851C (en) |
| AU (1) | AU684561B2 (en) |
| CA (1) | CA2136572A1 (en) |
| ZA (1) | ZA948925B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2123468A1 (en) * | 1997-06-26 | 1999-01-01 | Espanola Explosivos | Process and mechanism for in situ sensitization of aqueous explosives |
| US8512489B2 (en) | 2008-01-23 | 2013-08-20 | Orica Explosives Technology Pty Ltd | Mobile delivery platform for flowable explosive |
| CN105566017A (en) * | 2016-03-07 | 2016-05-11 | 湖北帅力化工有限公司 | Dissolving tank for powdery emulsion explosive ammonium nitrate |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AUPN737295A0 (en) * | 1995-12-29 | 1996-01-25 | Ici Australia Operations Proprietary Limited | Gasser composition & method of gassing |
| AUPN737395A0 (en) * | 1995-12-29 | 1996-01-25 | Ici Australia Operations Proprietary Limited | Process and apparatus for the manufacture of emulsion explosive compositions |
| AUPQ129199A0 (en) * | 1999-06-30 | 1999-07-22 | Orica Australia Pty Ltd | Manufacture of emulsion explosives |
| US7771550B2 (en) * | 2005-10-07 | 2010-08-10 | Dyno Nobel, Inc. | Method and system for manufacture and delivery of an emulsion explosive |
| CN106996725B (en) * | 2017-04-01 | 2018-09-04 | 深圳市金奥博科技股份有限公司 | A kind of portable explosive loader |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1072404A (en) * | 1992-05-28 | 1993-05-26 | 王立文 | Quick sensitization process for emulsified explosive |
-
1994
- 1994-11-10 ZA ZA948925A patent/ZA948925B/en unknown
- 1994-11-24 CA CA002136572A patent/CA2136572A1/en not_active Abandoned
- 1994-11-24 AU AU79022/94A patent/AU684561B2/en not_active Expired
- 1994-11-26 CN CN94114093A patent/CN1065851C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2123468A1 (en) * | 1997-06-26 | 1999-01-01 | Espanola Explosivos | Process and mechanism for in situ sensitization of aqueous explosives |
| WO1999000342A1 (en) * | 1997-06-26 | 1999-01-07 | Union Española De Explosivos S.A. | Process and mechanism for in situ sensitization of aqueous explosives |
| US6537399B2 (en) | 1997-06-26 | 2003-03-25 | Union Espanola De Explosivos, S.A. | Process and mechanism for in situ sensitization of aqueous explosives |
| US8512489B2 (en) | 2008-01-23 | 2013-08-20 | Orica Explosives Technology Pty Ltd | Mobile delivery platform for flowable explosive |
| CN105566017A (en) * | 2016-03-07 | 2016-05-11 | 湖北帅力化工有限公司 | Dissolving tank for powdery emulsion explosive ammonium nitrate |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA948925B (en) | 1995-07-18 |
| AU7902294A (en) | 1995-06-01 |
| CN1109459A (en) | 1995-10-04 |
| AU684561B2 (en) | 1997-12-18 |
| CN1065851C (en) | 2001-05-16 |
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