JPH0735500A - Control blasting method - Google Patents

Abstract

PURPOSE:To preserve performance quality such as detonatability, boosting properties, etc., for a long period by using high explosive or its cartridge which is formed by adsorbing and holding component containing oxidizer and water as main ingredients and substantially containing no viscous agent on particle surfaces of fine foam and/or between the particles. CONSTITUTION:A mixture of mixed salt solution of 90.5 pts. of ammonium nitrate 9.5 pts. of water and organic powder foam (fine particles containing isobutane in copolymer of vinylidene chloride and acrylonitrile) is dropped to a flat plate heated to 100-150 deg.C. Thus, high explosive obtained by adsorbing and holding the mixed salt solution on particle surfaces of fine organic foam and between the particles generated in the mixture while evaporating to reduce part of the water by 20-60wt.% is obtained. Then, the explosive is pressure-filled in a polyethylene laminated sheet cylinder as an explosive cartridge. Thus, even in the case of a long hole control blasting, interruption of explosion does not occur, and damage of a baserock can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safe control and blasting method for consuming industrial explosives.

[0002]

2. Description of the Related Art Conventionally, a special construction method called control blasting has been used for blasting when it is necessary to hold a peripheral wall of a tunnel, a wall of a space for underground equipment, and even a digging or a slope of an open face mining face. To be The purpose of this blasting method is 1) to prevent the rock wall from being destroyed as much as possible 2)
The goal is to make the wall surface as flat as possible, and specifically, line drilling, press splitting, cushion plasting, and deformation or combination thereof. ("New Blasting Handbook" Industrial Explosives Association, Sankaido) An example of such a controlled blasting method is
As disclosed in Japanese Examined Patent Publication No. 62-45479, there is a method of controlling the energy of the explosive by lowering the specific gravity of the slurry explosive.

[0003]

However, when the explosive diameter is made small in order to control the impact and pressure acting on the rock and a large gap is formed between the explosive diameter and the perforation diameter, the decoupling coefficient (perforation diameter / explosive diameter) is 2.0. In the vicinity, the impact and pressure acting on the bedrock will be relieved, but the impact of the preceding shock wave will be significant and the explosive property will be impaired, the detonation will be interrupted and non-residual will occur, impairing safe work at the consumer site. There was a problem called. Usually, when an explosive having a diameter of 20 mm and a hole diameter of 42 mm is used, the decoupling coefficient becomes 2.1, and the detonation interruption phenomenon becomes remarkable. Also, when using a normal explosive with a diameter of 42 mm and a diameter of 30 mm, the explosiveness is improved, the decoupling coefficient is 1.4, and the blasting interruption is unlikely to occur, but it is too powerful and damages the bedrock. Occurs. Therefore, in order to control the impact and pressure acting on the bedrock without reducing the diameter of the drug, the Japanese Patent Publication No. 62-4547 is used.
Although a method of reducing the blast energy by using a low-specific-gravity slurry explosive having a specific gravity of 0.6 to 0.9 has been attempted as disclosed in Japanese Patent Publication No. 9-90, it works on rock in the range of a decoupling coefficient of 1.0 to 1.5. The impact and pressure were not sufficiently relieved and only moderate effects were obtained. For this reason, an attempt was made to increase the decoupling coefficient to 1.5 or more to mitigate the impact and pressure acting on the bedrock, but the problem of increasing the frequency of detonation interruption phenomena was induced and put to practical use. Did not reach In particular, this tendency has a problem that in the recent controlled blasting method in which the blasting hole becomes longer than 2 m, the explosive interruption phenomenon further increases because the length of the explosive charge increases accordingly. A general method for adjusting the specific gravity of a water-containing explosive is performed by increasing / decreasing the amount of foam added, and when reducing the specific gravity, a large amount of foam is also added.
However, in the conventional water-containing explosives, in order to reduce the impact and pressure acting on the rock to a specific gravity region of 0.6 or less, which is sufficient, the amount of foam to be added increases, and the gel structure or emulsion structure of dense However, there is a problem that the performance is deteriorated and the performance such as detonation and transmission is deteriorated.
It has been a very difficult problem to stabilize the explosive property and the explosive property for a long period of time at a normal explosive diameter of 20 to 30 mm which can be used for controlled blasting in a region of 6 or less.

[0004]

In order to solve these drawbacks, the inventors of the present invention maintain quality by using polymers such as guar gum, which is a conventional water-containing explosive, and thickeners such as oils and emulsifiers thereof. Then, we are looking for a quality preservation method that does not depend on the said method,
As a result of intensive studies, conventional water-containing explosives are obtained by adsorbing and retaining a component containing an oxidizing agent and water as a main component and substantially not containing a thickening agent on the particle surface of the microfoam and / or between the particles. Established a method to preserve quality without substantially requiring polymers such as guar gum and oils and their emulsifiers, which are indispensable for quality assurance of The present invention has been completed by discovering that stable performance quality such as detonation performance and detonation performance can be maintained for a long time even in the vicinity of a decoupling coefficient of 2.0 where it is difficult to obtain stable detonation performance for a long time. .

That is, the present invention relates to an explosive or a composition in which a component containing an oxidizing agent and water as a main component and containing substantially no thickening agent is adsorbed and retained on the surface of particles of the fine foam and / or between the particles. This is a controlled blasting method that can cut rock without causing damage to the rock and without damaging the bedrock by combining a medicine package and the controlled blasting method. The explosive of the present invention is
The gel structure of conventional water-containing explosives is formed by stably forming a structure that adsorbs and retains on the surface of particles or in the spaces between particles of a microfoam that collects a high-concentration salt solution containing oxidizer and water as main components. And the function of the emulsion structure, that is, the function of suppressing crystals that grow from a high-concentration salt solution and the uniform dispersion of components are stably maintained for a long period of time. Therefore, the explosive of the present invention does not substantially require a thickener and its cross-linking agent or oils and its emulsifier, which were indispensable for maintaining performance and quality in conventional hydrous explosives, and has a long-term performance quality. It is possible to maintain the performance quality for a long period of time even in the low specific gravity region where it was difficult to maintain stable performance quality with the conventional water-containing explosive. The structure of the explosive of the present invention is also formed by uniformly mixing the organic unfoamed fine particles that foam when heated and the high-concentration salt solution, and heating the mixture to foam the unexpanded fine particles. Alternatively, it can also be formed by heating the above-mentioned high-concentration salt solution to reduce the solid salt content and then mixing with the aggregate of the fine foam particles.

The fine foam used in the present invention includes:
For example, glass, shirasu, alumina, sodium silicate, pearlite, obsidian, and other inorganic foams of 1000 microns or less, phenolic resins, epoxy resins, urea resins, polyvinylidene chloride, vinylidene chloride-acrylonitrile copolymer, chloride Vinylidene chloride-based copolymers such as vinylidene-methyl methacrylate copolymers, and organic foams of 500 μm or less obtained from vinyl polymers such as polystyrene, polymethylmethacrylate, and polyvinyl chloride. Organic foams are preferable, and in particular, vinylidene chloride-acrylonitrile copolymer, acrylonitrile / methyl methacrylate copolymer [Expansel Co., Ltd .; 053WU (registered trademark)] unexpanded fine particle foam or expanded fine particles [Expand Cell Exp; Expancel (registered trademark)] is a suitable fine foam that maintains a stable explosive property.

If the particle size of the fine foam is 1000 microns or less, it can be sufficiently used, but a more preferred particle size is 150.
It is less than micron. Further, in order to suppress the crystal growth from the high-concentration salt solution and stabilize the performance for a long period of time, it is preferable that the spherical surface is substantially spherical and the surface of the sphere is hydrophilic and smooth. The microfoam used in the present invention has a total composition of 1 to 20.
% Is used, and if it is less than 1% by weight, the amount of high-concentration salt solution adsorbed and retained by the microfoam is small, which promotes deterioration of performance over time. On the other hand, if it exceeds 20% by weight, the explosive property is deteriorated. The organic microfoam is not only capable of adjusting the specific gravity with a small amount as compared with the inorganic microfoam, but is also an excellent specific gravity adjusting agent having a function of a combustible agent. In addition, the optimum explosive density that enables precise control blasting in the present invention is 0.2 to
The area is 0.6.

The oxidizing agent used in the present invention is a salt of an inorganic acid such as nitric acid, chloric acid or perchloric acid such as ammonium, alkali metal or alkaline earth metal, which may be used alone or in combination. Among these, ammonium nitrate and sodium nitrate are suitable oxidizing agents that are inexpensive and highly reactive. In the present invention, the oxidizing agent is used in an amount of 45 to 95% by weight based on the total composition. If it is less than 45% by weight, the oxygen balance will be negative and the gas after blasting will be poor, and if it exceeds 95% by weight, the solid component will be excessive in the explosive component and the explosive property will be impaired. It is preferably 55 to 90% by weight. The water used in the present invention is used in an amount of 2 to 20% by weight based on the total composition. If it is less than 2% by weight, the solid content increases and the detonation performance deteriorates. On the other hand, if it exceeds 20% by weight, the medicinal property becomes soft and the handleability becomes poor.

In the present invention, a sensitizer is not always necessary, but alkylamine nitrates such as monomethylamine nitrate and monoethylamine nitrate, hydrazine nitrate or ethylene glycol mononitrate, which are used in general slurry explosives, can be used. Of these, monomethylamine nitrate is particularly preferable because it is easy to adjust the explosive and to obtain stable explosive properties for a long period of time. The auxiliary sensitizer used may be one used in ordinary slurry explosives. For example, if paint-grade aluminum powder is used as the auxiliary sensitizer, a better explosive property can be obtained. Although the present invention does not necessarily require a sharpening agent, the sharpening agent for easily obtaining stable performance is used in an amount of 10 to 40% by weight based on the whole composition. If it is less than 10% by weight, the detonation property at low temperatures in winter will be deteriorated, and if it exceeds 40% by weight, the sensitivity will be high and the safety during production will be impaired. It is desirable to set it to 15 to 30% by weight.

As other components used in the present invention,
There are surfactants such as phosphates, decomposition inhibitors such as urea, and oxygen balance regulators such as coal powder and starch. or,
The thickener is not necessary in principle, but does not limit its use, because it increases the production viscosity and causes unnecessary voids between the fine hollow particles to cause performance deterioration. The method for producing an explosive of the present invention comprises, for example, heating and mixing a salt solution in which a predetermined amount of ammonium nitrate, sodium nitrate, water and, if necessary, each of ammonium nitrate, such as monomethylamine, which aids the decomposition of ammonium nitrate is mixed at a temperature of 50 to 70 ° C. To produce a mixed salt solution in which most of the salt solids are dissolved. Then, the mixed salt solution is added to and mixed with a specified amount of the microfoam, and the mixed salt solution is adsorbed and retained (adhered) between the surfaces of the microfoam particles and particles, ammonium nitrate, water, and a necessary method. According to the above, a mixture of a mixed salt solution in which a predetermined amount of each of amines such as monomethylamine nitrate which assists decomposition of ammonium nitrate is mixed and expandable organic unexpanded particles are added in an amount of 80 to 15
Heating to 0 ° C. to foam the organic unexpanded particles, and adsorb the mixed salt solution to the particle surfaces of the foam and between the particles,
This is a method for obtaining an explosive composition by a method of holding (adhering) the structure. The explosive composition obtained by heating foaming varies in a decreasing direction due to evaporation of water contained in the composition depending on its foaming condition, or a part of the foam is broken to present a fused state by detonation or detonation. It is an excellent manufacturing method with improved water resistance.

[0011]

The present invention will be described with reference to the following examples. In addition,
The following methods were used to measure the naked explosion velocity, detonator ignitability, blast length, and degree of cracking of the iron pipe. (Nude explosive speed) Explosive package (25m diameter) filled in a polyethylene laminated paper tube or nylon 66 film tube in advance.
m, drug length 300 mm) was detonated with a No. 6 detonator, and the detonation speed was measured by the ion gap method. In addition, one year after the production was additionally measured to evaluate the performance over time.

(Detonator detonation property) An explosive bag (25 mm diameter, 100 mm length) charged in advance in a polyethylene laminated paper cylinder or nylon 66 film tube is used for about -5 to-
After storing it in a freezer at 20 ° C. for about 10 hours, it was detonated with a No. 6 detonator, and the temperature of the medicine when the explosive package was completely detonated was measured. still,
One year after production was additionally measured for performance evaluation with time. (Explosion length and degree of cracking of iron pipe) Explosive package filled in polyethylene laminated paper cylinder or nylon 66 film tube in advance (drug diameter 25 to 30 mm, drug length 150 to 300 m)
m) is an iron pipe (tube diameter 28-68 mm, pipe length 300 cm)
Charged (a charge length of about 300 cm), detonated one end of the charged explosive packet with a No. 6 detonator, and measured the length of the explosive packet complete explosion as the transmission length. The quality of the broken state of the steel pipe was measured as the degree of cracking of the steel pipe. In addition, one year after the production was additionally measured to evaluate the performance over time.

Examples 1 to 3 90.5 parts of ammonium nitrate, water 9.
A mixture of 5 parts of the mixed salt solution and the amount of the organic unfoamed product (fine particles of vinylidene chloride-acrylonitrile copolymer-containing isobutane) shown in Table 1 was placed on a flat plate heated to 100 to 150 ° C. By dripping, the mixed salt solution is adsorbed and retained between the particles on the particle surfaces of the organic microfoam produced in the mixture while evaporating and reducing a part of the water by about 20 to 60% by weight. An explosive having the density shown in Table 1 below was obtained. Then, the above explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 1) to form an explosive package. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

(Examples 4 to 5) A mixed salt solution of 45 parts of ammonium nitrate, 30 parts of monomethylamine nitrate nitrate, 9 parts of water and 16 parts of sodium nitrate and the organic unfoamed materials (vinylidene chloride and acryl) in the amounts shown in Table 1 were used. A mixture of a nitrile copolymer and fine particles in which isobutane was included) was filled in a medicine package of nylon 66 film tube (the diameter of the medicine shown in Table 1) to allow for the expansion, and the air in the container space was substantially filled. After degassing, the medicine package is heated at 80 to 150 ° C. to adsorb and hold the mixed salt solution on the surface of foamed particles or in the spaces between particles. As a result, an explosive having the density shown in Table 1 in which the organic resin layer is formed on the surface of the explosive inside the medicine package is obtained. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

(Example 6) Ammonium nitrate 45 parts, monomethylamine nitrate nitrate 30 parts, water 9 parts, sodium nitrate 1
A mixture of 6 parts of the mixed salt solution and the amount of the organic unfoamed product (fine particles of vinylidene chloride-acrylonitrile copolymer-containing isobutane) shown in Table 1 was placed on a flat plate heated to 100 to 150 ° C. By dripping, the mixed salt solution is adsorbed and retained between the particles on the particle surfaces of the organic microfoam produced in the mixture while evaporating and reducing a part of the water by about 20 to 60% by weight. An explosive having the density shown in Table 1 below was obtained. Then, the above explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 1) to form an explosive package. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

(Examples 7 to 8) A mixed salt solution of 45 parts of ammonium nitrate, 30 parts of monomethylamine nitrate nitrate, 9 parts of water, and 16 parts of sodium nitrate and the organic microfoam in the amount shown in Table 1 [Expansel 551DE (Registered trademark; manufactured by Expancel Co., Ltd.) was mixed to obtain an explosive having a density shown in Table 1 obtained by adsorbing and retaining the mixed salt solution on the particle surfaces of the organic microfoam and between the particles. Then, the above explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 1) to form an explosive package. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

Example 9 45 parts of ammonium nitrate, 30 parts of monomethylamine nitrate nitrate, 9 parts of water, 1 part of sodium nitrate
6 parts of the mixed salt solution and the amount of organic microfoam [Expansel 551DE (registered trademark); manufactured by Expancel Co.] and microfoam [Scotchlite (registered trademark); B
28/750; manufactured by 3M Co., Ltd.], and the mixed salt solution is adsorbed on the surface of particles of the fine foam and between the particles.
An explosive having a density described in Table 1 was obtained. Then, the above explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 1) to form an explosive package. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

Example 10 A mixed salt solution of 45 parts of ammonium nitrate, 30 parts of monomethylamine nitrate nitrate, 9 parts of water and 16 parts of sodium nitrate and the amount of organic microfoam shown in Table 1 [Expansel 551DE (registered) Trademark); manufactured by Expancel Co., Ltd.] and inorganic fine foam [Winlite (registered trademark); MSB5011; manufactured by Idiji Kasei] are mixed, and the mixed solution is adsorbed and retained between the particle surfaces of the fine foam and between the particles. Thus obtained explosive having a density shown in Table 1 was obtained. Then, the above explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 1) to form an explosive package. Then, after 5 days, the naked explosive velocity of the explosive, the detonation initiation property, the explosive property, and the cracking condition of the iron pipe were measured. The results are shown in Table 1.

[0019]

[Table 1]

A comparative example is shown below. (Comparative Examples 1 to 3) A high-concentration salt solution containing 50 parts of ammonium nitrate, 28 parts of monomethylamine nitrate nitrate, and 12 parts of water is prepared.
Then, to the above-mentioned high-concentration salt solution, the amount of organic microfoam [Expan 551DE (registered trademark); manufactured by Expancel Co.] and inorganic microfoam [Scotchlite (registered trademark); B28 / 750; [Manufactured by the company] is added and mixed, and then 1 part of guar gum and 7 parts of sodium nitrate are added and uniformly mixed. Then, 2 parts of aluminum powder was added, and a trace amount of a cross-linking agent [Riox; Sansho Co., Ltd.] was uniformly mixed to obtain a slurry explosive having a density shown in Table 2. Then, the above-mentioned slurry explosive was charged under pressure into a polyethylene laminated paper cylinder (the diameter of the medicine package shown in Table 2) to form an explosive package. Then, after 5 days, the bare explosion speed, detonator detonation property, detonation property and cracking degree of the iron pipe of the slurry explosive were measured. The results are shown in Table 1.

Comparative Examples 4 to 6 78.3 parts of ammonium nitrate and 4.7 parts of sodium nitrate were added to 11.6 parts of water and completely dissolved at 90 ° C. to obtain a high concentration salt solution. On the other hand, 2.7 parts of carbonaceous fuel [Polywax (registered trademark); 655; manufactured by Toyo Petrolite Co., Ltd.] and 2.7 parts of sorbitan monooleate as an emulsifier are melt-mixed at 90 ° C. to obtain a mixture of combustible agents. . Slowly add the high-concentration salt solution to this,
Stirring emulsification was performed under heating at 90 ° C. After emulsification, the mixture was further stirred at high speed to obtain an emulsion. Then, the amount of the inorganic micro-foam shown in Table 2 [Scotchlite (registered trademark) B28 / 7]
50; manufactured by 3M Co., Ltd.] and the emulsion are 70-
An emulsion explosive having a density shown in Table 2 was obtained by mixing and mixing at 80 ° C. Then, the above-mentioned emulsion explosive was pressure-filled into a polyethylene laminate paper cylinder (the diameter of the medicine package shown in Table 2) to give an explosive package. After that, the naked explosion speed, detonator detonation property, detonation property, and cracking degree of the iron pipe of the emulsion explosive after 5 days were measured. The results are shown in Table 2.

[0022]

[Table 2]

[0023]

EFFECTS OF THE INVENTION The controlled blasting method of the present invention, unlike conventional controlled blasting, does not cause detonation interruption even in long hole controlled blasting, and since it does not damage the bedrock, it is efficient and safe at the blasting site. Sex is significantly improved.

Claims (1)

[Claims] 1. A microfoam particle surface and / or a component containing an oxidizing agent and water as a main component and containing substantially no thickening agent.
Alternatively, a controlled blasting method characterized by using an explosive or a sachet thereof that is adsorbed and held between particles.