A method for loading ANFO explosives without anchor bag retrieval.

Abstract

To provide an ANFO explosive blast method in which a part or whole of an anchor bag covering inside a blast hole is made of bioplastic and which eliminates the need for the anchor bag collection after blast.SOLUTION: In an explosive loading detonation method without the need for an anchor bag collection after ANFO explosive loading detonation, the anchor bag covering inside a blast hole is manufactured using a biomass plastic or a biodegradable plastic.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a method for loading ammonium nitrate oil explosives (ANFO explosives) into blast holes, and to an improvement in the automatic loading method for ANFO explosives using a long anchor bag made of plastic film. [Background technology]

[0002] ANFO explosives have a lower explosive performance than other industrial explosives (dynamite and emulsion-based water-containing explosives), but they are safe, inexpensive, and, depending on how they are used, can exert a strong force and effectively crush tunnels, so they have been used in many blasting works in recent years. Therefore, in order to safely and efficiently advance tunnel construction work aimed at early completion, a remote explosive loading device that can automate a series of ANFO explosive loading operations has been proposed for the purpose of avoiding dangers at the tunnel face and reducing difficult work by improving working posture (Non-Patent Document 1).

[0003] However, as shown in Figure 3, the explosive loading process requires loading a cartridge explosive, which is an explosive packaged in paper or plastic film, as the parent die at the bottom of the blasthole, and then loading fluid explosives (additive die) such as ammonium nitrate oil explosive (ANFO), bulk emulsion explosive, and slurry explosive from a chute using compressed air and water. Then, bean paste is supplied from a bean paste supply feeder behind the fluid explosives, which is then molded in a bean paste molding device and then supplied to the blasthole from the loading pipe of the loading hose. After filling the hole with bean paste (clay), the parent die is detonated to explode the fluid explosives. This requires the use of a complex explosive loading device. Therefore, as a result of intensive research, the inventor proposed an automatic loading method of ANFO explosives, in which a long plastic film anchor bag is used to cover the inside of a blast hole, a parent die serving as an explosive is attached to the tip of a loading pipe and inserted into the anchor bag to load it at the bottom of the blast hole, and ANFO (Ammonium Nitrate Fuel Oil explosive) explosive is pumped behind it. Here, the anchor bag is made of a soft synthetic resin material and is flexible, with a sealed tip and a hose with a larger diameter than the open blast hole at the rear end. Due to the nature of the ANFO explosive, the anchor bag is a flexible hose with a larger diameter than the blast hole, and this combined with the fact that the anchor bag is a flexible hose with a larger diameter than the blast hole makes the filling rate of the ANFO explosive in the blast hole as close to 100% as possible, allowing sufficient sealing of the blast hole and obtaining a predetermined blasting efficiency, and the inventor has completed an automatic loading method of ANFO explosives (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Application No. 2021-82178 [Non-patent literature]

[0005] [Non-Patent Document 1] Efforts to fully automate explosives loading using a remote explosives loading system (Kumagai Gumi) Summary of the Invention [Problem to be solved by the invention]

[0006] In this way, the automatic explosives loading method can eliminate the complexity and danger of blasting work and improve the working environment, but because it uses long plastic anchor bags, the recovery work of the crushed anchor bags after blasting is complicated, which deteriorates the blasting workability and the working environment. Therefore, the objective of this invention is to eliminate the difficulty of recovering the anchor bags in the automatic loading of ANFO explosives. [Means for solving the problem]

[0007] The present invention has been made to solve the above-mentioned problems, and is characterized in that the method of loading blast hole explosives into a blast hole using an anchor bag of ANFO explosive comprises: (1) a process of loading the ANFO explosive into the drilled hole in a water-sealed state using an anchor bag made of plastic film that uses bioplastics in part or in whole; and (2) a process of leaving the anchor bag crushed material mixed into the soil generated after blasting without separating it and allowing it to decompose naturally. Effect of the Invention

[0008] According to the present invention, the ANFO explosive is loaded into the blast hole using an anchor bag, and the anchor bag used to load the ANFO explosive after blasting disperses in the soil and sand when blasting, but since it is made of a plastic material containing bioplastic in part or in whole, it is collected together with the soil and sand when blasting, but since it is naturally degradable, it decomposes and disappears over time even if it is left without being separated and collected from the soil and sand. Therefore, the excavation work environment is not polluted by fragments of the anchor bag.

[0009] The feature of the present invention is that a parent die or explosive that will be the detonator is loaded using an anchor bag made of a soft bioplastic film with a diameter larger than the blast hole, and the blast hole behind the parent die is filled with ANFO explosive by pressure and sealed, and the anchor bag is left without being collected after detonation. Normally, in a blast hole with a diameter of 45 cm, even if a packaged ANFO explosive (30 cmΦ) is stopped behind the parent die, the loading rate of the fluid explosive in the blast hole is not sufficient, and it is necessary to seal the blast hole using an anchor. In the present invention, the parent die or explosive that will be the detonator is attached to the tip of the loading pipe, the loading pipe is inserted into the blast hole together with the anchor bag, and after the parent die is set, the loading pipe is pulled out from the anchor bag, and the ANFO explosive is pressure-fed from the loading pipe to the back of the parent die, thereby improving the filling rate of the blast hole to nearly 100%, and sufficient blasting efficiency equivalent to sealing with an anchor can be obtained. Therefore, the present invention is not only revolutionary in that it enables safe and efficient automatic loading of explosives, but also prevents environmental pollution because the anchor bag uses degradable bioplastic and is left to decompose without the need for separate collection.

[0010] According to the present invention, the parent die is covered by an anchor bag and is loaded into the blast hole. In addition, the soft anchor bag protects the 0.4 to 0.42 mmΦ lead wire from the detonator of the parent die from damage. In addition, since the flexible bag is made to an arbitrary outer diameter slightly larger than the blast hole diameter, even if the inner wall of the blast hole is rough, it is covered with the anchor bag, so that the filling rate can be made close to 100% by pumping the ANFO explosive behind the explosive of the parent die. Normally, if the ANFO explosive is not used, the explosive may not reach the back of the blast hole due to resistance from small protrusions in the blast hole, but in the present invention, even if there are such protrusions, the explosive is flattened by the anchor bag, and since a slip agent is added, it is possible to load it further into the hole. Therefore, not only is it not necessary to seal the entrance of the blast hole with an anchor, but the filling rate can be improved, and automatic loading of explosives into the blast hole can be realized safely and easily.

[0011] Also, even though the lower half of the tunnel has many water holes, the bulk ANFO is not water resistant, which is a problem, but according to the present invention, by using anchor bags for automatic loading, it has the same effect as using bulk ANFO to create the largest diameter piece ANFO on-site. Therefore, it is possible to obtain the loading of ANFO explosives with the largest hole diameter, resulting in a high filling rate and high blasting efficiency.

[0012] The anchor bags used in the present invention are originally made of soft synthetic resin materials to make them flexible, but bioplastics are used as part or all of the plastic material to eliminate the need for recovery after blasting. As a result, the anchor bags disperse and become mixed into the soil after blasting, but they naturally decompose, making recovery unnecessary. Here, bioplastics is a general term for "biodegradable plastics" that are biodegraded by microorganisms, and "biomass plastics" that are manufactured using biomass (biological organic resources such as starch and cellulose) as raw materials. The former in particular are called "green plastics" or "green pla," and there is a system for identifying and labeling them, which contributes to environmental conservation. Here, biodegradable plastics are plastics that are biodegraded by bacteria or organisms, and examples of such plastics include chemically synthesized products selected from the group consisting of polylactic acid, polycaprolactone, polybutylene succinate, polyethylene succinate, polyvinyl alcohol, polyglycolic acid, poly(caprolactone / butylene succinate), poly(butylene succinate / adipate), poly(ethylene terephthalate / succinate), and poly(tetramethylene adipate / terephthalate), and natural products consisting of polyhydroxybutyric acid, esterified starch, cellulose acetate, chitosan, and starch-based green plastic. If a part or all of the anchor bag is made of biodegradable plastic, it can be used in the method of the present invention. Typically, mixing 5 to 30% by weight of biodegradable plastic into soft polyethylene can increase the decomposition property of the soft plastic film after blasting. On the other hand, biomass plastics include bio-PET, bio-PTT, bio-PP, bio-PU, bio-PA610, bio-PE, bio-PA11, and bio-PA1010, which are made from petrochemical-derived raw materials and biomass-derived raw materials, and can constitute part or all of the anchor bag. Typically, the anchor bag can be produced by mixing and adding 5 to 30% by weight of biomass plastic to soft polyethylene and molding it. In addition, it is preferable to perform antistatic treatment. For example, antistatic treatment can be performed by mixing, dispersing, or incorporating conductive fibers, conductive powders, metal fibers, metal powder particles, or metal wires into the synthetic resin material of the bag.If necessary, a slip agent is preferably added to the bag and applied to the surface of the bag.

[0013] Since the outer diameter of the bag is usually 45φmm, it has been found that the filling density of ANFO can be almost 100% by pressure-feeding the bag using an anchor bag with an outer diameter 5% or more, preferably 10 to 15% larger than the diameter of the blast hole. If the tip is slanted, it can be easily inserted into the blast hole, but it may be flat. On the other hand, it is preferable to fold the loading port to make it stronger, since it is easier to insert the loading pipe. If the bag is too thin, it is easy to break, and if it is too thick, it does not fit the inside of the blast hole, reducing the filling rate of the ANFO explosive being pressure-feed. Therefore, it is appropriate to make the anchor bag flexible by using a film with a thickness of about 0.02 mm to 0.2 mm, and a preferable form that can obtain a high filling efficiency by pressure-feeding is selected taking into consideration the state of the blast hole and the fluidity of the ANFO explosive. To make an anchor bag with excellent filling efficiency and degradability, it is preferable to mix 5% to 30% by weight of biomass plastic or green plastic with soft plastic to give it flexibility and degradability, but the physical properties can be adjusted by changing the mixing ratio depending on the application.

[0014] The ANFO explosive used in the present invention is an explosive that is composed of ammonium nitrate and fuel oil (flash point 50°C or higher), does not contain other gunpowder, explosives, metal powder, etc., and does not detonate with an industrial detonator or electric detonator, and is widely available on the market. An example of the composition is one that is composed of 94% ammonium nitrate and 6% fuel oil. Usually, it is supplied as a detonator that detonates and propagates other explosives (dynamite, etc.). Around the parent die or cartridge explosive, a bulk emulsion explosive, a slurry explosive, or other fluid explosive may be mixed with an ammonium nitrate oil explosive (ANFO) in place of a part of the ANFO explosive, and the fluidity may be adjusted and the explosive may be loaded. In the present invention, the physical properties of the fluid explosive represented by such an ANFO explosive can be used to increase the filling rate and eliminate the sealing of the blast hole with anko, but anko sealing may be performed as in the conventional manner. The filling density of the ANFO explosive may be uniform, or the filling density may be increased from the back to the entrance. The purpose of filling the ANFO is to obtain the effect of sealing the blast hole with the filling material. The end of the anchor bag is folded back to make it thick, so it can be packed into the end of the blast hole together with the filling material. [Brief description of the drawings]

[0015] [Figure 1] 1 is an overall view showing an outline of an automatic explosive loading system used in the present invention. [Figure 2A] This is a process diagram showing steps (1) to (4) of the automatic explosives loading method of the present invention, in which: (1) a parent die 20 is attached to the tip of a loading pipe 10; (2) a biodegradable plastic anchor bag 20 is prepared; (3) the loading pipe 10 with a parent die 21 attached is inserted into the anchor bag 20; and (4) the loading pipe 10 with the parent die attached and inserted therein is loaded into a blast hole 30 together with the anchor bag 20. [Figure 2B]In this process diagram showing steps (5) to (7) of the automatic explosive loading method of the present invention, (5) the parent die 20 is removed from the tip of the loading pipe 10, (6) the loading pipe is pulled out of the blast hole while the bulk ANFO explosive is pumped into the anchor bag 20, and the ANFO explosive is loaded behind the parent die 21. Then (7) a sufficient amount of ANFO explosive is loaded, and it may be detonated as is or as if it were packed with bean paste. [Diagram 3] FIG. 1 is a diagram showing the configuration of a conventional automatic explosive loading device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The automatic explosives loading method according to the present invention is comprised of steps (1) to (7) and is shown in Figures 2A and 2B. The steps shown in Figure 2A are (1) a step of attaching a parent die 21 to the tip of a loading pipe 10, (2) a step of preparing a biodegradable plastic anchor bag 20 into which the loading pipe 10 is inserted, (3) a step of inserting the loading pipe 10 with the parent die 21 attached to the tip into the anchor bag 20, and (4) a step of inserting the anchor bag 20 containing the loading pipe 10 into a blast hole 30. The loading pipe 10 enclosed in the anchor bag 20 is (5) inserted into the blast hole 30, as shown in Figure 2B, and the parent die 21 is inserted into the back of the loading pipe 10. The process comprises the steps of: (1) setting a die 21, separating the parent die 21 from the loading pipe 10, and gradually pumping and filling the area behind the parent die 21 placed at the back of the blast hole 30 through the anchor bag 20 while pulling the loading pipe 10 out of the blast hole 30; (2) pumping and filling the area behind the parent die 21 with an almost 100% filling density while pulling the loading pipe 10 out; and (3) filling the area behind the parent die 21 with an almost 100% filling density after completing the ANFO filling 22, and packing the end 20a of the anchor bag 20 into the blast hole 30 to seal it. In the present invention, after blasting, the process comprises the step of simultaneously collecting the pieces of the anchor bag that exploded and scattered from the soil after blasting without separating and collecting them separately. This is because the anchor bag is made of biodegradable plastic, and is decomposed and disappears by leaving it alone without being separated and collected from the soil as in the conventional method. The present invention will now be described in detail with reference to the specific examples shown in the drawings. FIG. 1 is a schematic diagram of the device used in the automatic explosive loading method according to the present invention. As shown in the figure, a trolley 40 is equipped with a rock drill 41 and a loader 42, and the loading hose 11 and loading pipe 10 are operated from a remote loading device 51 mounted on a rear vehicle 50. The remote explosive loading device 51 is composed of the explosive supply, anco supply, and loading devices and a computer that controls them. The current loading procedure for this device is as follows: first, a parent die (explosive + detonator) is attached to the tip of the loading pipe, and air pressure is used to feed it to the end of the blast hole. Next, a specified number of additional dies (explosive only) is set using a control button on hand, and when the additional die firing command button is pressed, the set number of additional dies are continuously pressure-fed and loaded into the hole. Once the loading of all the additional dies has been confirmed, a command to load the anchor is issued and a specified number of continuously shaped anchors are pumped through the same loading device. In the present invention, however, an anchor bag 20 is attached to the tip of the loading pipe 10, and steps (1) to (4) shown in Figure 2A and steps (5) to (7) shown in Figure 2B are repeated to automatically load explosives into each blast hole 30 by remote control. As described above, after the parent die 21 is set at the tip of the pipe 10 and set in the anchor bag 20 and inserted into the blast hole 30, the parent die 21 can be detached from the loading pipe 10 by simply operating a button at hand, and the ANFO explosive can be automatically pumped and loaded from the rear cart via a hose. In the conventional manual loading work, the worker had to insert the parent die, additional die, and filling die while pushing with a wooden filling rod in a state of being in close contact with the face for a long time, but the loading work by the automatic loading method by remote control of the explosives allows the worker to load the explosives in a relatively comfortable position from a position about 1.5 m away from the face, which not only improves the safety of the face work but also reduces physical fatigue by being able to load the explosives in a comfortable position. Moreover, since the sealing of the blast hole with filling die is no longer necessary due to the filling of the ANFO explosives, the automatic loading work is also reduced, making it easy to carry out.

[0017] In the present invention, an anchor bag 100 made of biodegradable plastic is used for automatic explosive loading. The bag 100 is made of a biodegradable synthetic resin material, for example, a degradable soft plastic obtained by mixing 5 to 20% by weight of biomass plastic made from sugar cane with soft polyethylene resin, and is made into a hose shape with a larger diameter than the diameter of the blast hole 30 by extrusion molding or the like, with the front end sealed and the rear end open. For example, when the diameter of the blast hole 40 is 45φmm, the bag is made into a hose shape with an outer diameter D of 48φmm to 52φmm and a thickness of 0.02mm to 0.2mm. The loading hole 20a is made to be larger than the diameter of the blast hole 30. For example, when the diameter of the blast hole 30 is 45φmm, the outer diameter of the loading hole 20a is slightly larger than the cutting diameter.

[0018] In the above embodiment, biomass plastic originating from sugar cane was used as the biodegradable plastic, but other biodegradable plastics or biomass plastics may be used. It goes without saying that a person skilled in the art can make some modifications without departing from the gist of the present invention. [Explanation of symbols]

[0019] 10 Loading Pipe 20 Degradable anchor bag 21 Parent Die 22 ANFO explosives 30 Blast Holes

Claims

1. In a blasting system in which ANFO explosives are loaded into a blast hole using an anchor bag, A blasting method comprising the steps of: (1) forming the anchor bag using a bioplastic or a soft polyethylene resin containing 5 to 30% by weight of bioplastic, loading the anchor bag with an ANFO explosive, and loading the ANFO explosive into a drilled hole in a water-sealed state; and (2) leaving the crushed anchor bag material mixed into the soil generated after blasting without separating it, and allowing it to decompose naturally.

2. The method according to claim 1, characterized in that the anchor bag is a long bag that forms a cylindrical pipe with a diameter that is 5% or more larger than the diameter of the blast hole, with the tip tapered at an angle up and down and the rear end folded over to make it thicker.

3. 2. The method according to claim 1, wherein the bioplastic used in the manufacture of the anchor bag is a biodegradable plastic or a biomass plastic, the biodegradable plastic being a plastic that can be biodegraded by bacteria or organisms, and being selected from the group consisting of chemically synthesized products selected from the group consisting of polylactic acid, polycaprolactone, polybutylene succinate, polyethylene succinate, polyvinyl alcohol, polyglycolic acid, poly(caprolactone / butylene succinate), poly(butylene succinate / adipate), poly(ethylene terephthalate / succinate), poly(tetramethylene adipate / terephthalate), and natural products consisting of polyhydroxybutyric acid, esterified starch, cellulose acetate, chitosan, and starch-based green plastics, while the biomass plastic is selected from the group consisting of Bio PET, Bio PTT, Bio PP, Bio PU, Bio PA 610, Bio PE, Bio PA 11, and Bio PA 1010, which are made from petrochemical-derived raw materials and biomass-derived raw materials.

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