Blasting construction method for branch draw shaft of underground mine

Abstract

The invention provides an underground mine branch draw shaft blasting construction method, belongs to the technical field of underground mine construction, and aims to solve the problem of difficulty in underground mine branch draw shaft construction in the prior art. The invention provides an underground mine branch draw shaft blasting construction method which comprises the following steps: a preparation step: the axis of a branch draw shaft is determined according to the positions of a main draw shaft, a first middle section and a second middle section, and the branch draw shaft is connected with the main draw shaft and the second middle section; drilling: drilling a blast hole group from the second middle section to the main draw shaft by taking the axis of the branch draw shaft as a reference line; and blasting: filling blasting cartridges in the blasting hole group and detonating, wherein blasting scraps fall into the main draw shaft to form a branch draw shaft. The method comprises the steps of preparation, drilling and blasting, specifically, the branch draw shaft is formed by determining the axis of the branch draw shaft, drilling a blast hole group and detonating the blast hole group. The construction process of the underground mine branch draw shaft is simplified, and the problem of construction difficulty is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of underground mine construction, and in particular relates to a blasting construction method for a branch chute of an underground mine. Background Art

[0002] In the process of underground mining, in order to improve the efficiency of ore transportation, the ore is usually lowered and transported out of the middle section through the main chute. The main chute is the main channel for ore transportation, and its bottom is connected to the transportation equipment to ensure that the ore can be transported out smoothly. However, for other middle sections in the mine, due to geographical restrictions, the main chute cannot be used directly for ore lowering. Therefore, it is necessary to set up branch chutes to guide the ore in these middle sections to the main chute.

[0003] The establishment of branch chutes is a complex project. Since each section is located underground and the geological conditions are complex, the connection method of the branch chutes must be designed and constructed based on detailed exploration results. During the construction process, the starting end of the branch chutes is located in other sections, and the outlet end is connected to the main chute. The branch chutes are all deep underground. In addition, the branch chutes often extend obliquely, which further increases the difficulty of construction.

[0004] How to efficiently and safely complete the construction of branch chutes in an underground environment with complex geological conditions and limited space has become a technical problem that needs to be urgently solved in current underground mining. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a blasting construction method for underground mine branch chutes, which is used to solve the problem of difficulty in construction of underground mine branch chutes in the prior art.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides an underground mine branch chute blasting construction method, comprising the following steps: Preparation step: determining the axis of the branch chute according to the positions of the main chute, the first middle section and the second middle section, wherein the branch chute connects the main chute and the second middle section; Drilling step: using the axis of the branch chute as a reference line, drilling a blasting hole group from the second middle section toward the main chute; Blasting step: filling blasting cartridges into the blasting hole group and detonating them, and causing blasting debris to fall into the main chute to form a branch chute.

[0007] Optionally, in the preparation step, when determining the axis of the branch chute, the axis of the branch chute and the axis of the main chute are located in the same plane, and this plane is used as the central plane.

[0008] Optionally, in the drilling step, when drilling a blasting hole group, a reference hole is first drilled along the axis of the branch chute, the reference hole penetrates the soil from the second middle section and enters the main chute, the angle difference of the axis of the reference hole relative to the center plane is measured, the drilling angle of the drilling equipment is adjusted according to the angle difference, and the reference hole is re-drilled until the axis of the reference hole is located in the center plane.

[0009] Optionally, the drilling angle of the drilling equipment is not changed, and the drilling equipment is only translated to drill the remaining holes of the blasting hole group parallel to the reference hole.

[0010] Optionally, the blasting hole group includes a pre-splitting hole group, an auxiliary hole group and a slotting hole group; The pre-splitting hole group is distributed at the outermost periphery of the blasting hole group; The cutout hole group is distributed in the central area of ​​the blasting hole group, and includes a central hole and surrounding holes surrounding the central hole; The auxiliary hole group is located between the pre-splitting hole group and the slotting hole group, and the auxiliary hole group is arranged in layers.

[0011] Optionally, the cutout hole group is located in the central area of ​​the area enclosed by the pre-splitting hole group, and at least one layer of auxiliary holes forms a ring surrounding the cutout hole group; Alternatively, the cutout hole group is biased toward one side of the area enclosed by the pre-splitting hole group, and at least one layer of auxiliary holes forms an arc surrounding the cutout hole group.

[0012] Optionally, in the blasting step, when filling the blasting charge: The central hole of the cutout hole group is charged according to the first mode, and the surrounding holes are left empty and uncharged; The auxiliary hole group is also charged according to the first mode; The pre-splitting hole group is charged according to a second mode; The first mode of charging refers to charging in sections along the axis of the hole, with fillers between the sections; the second mode of charging refers to charging in entire sections along the axis of the hole.

[0013] Optionally, in the blasting step, during blasting: The pre-cracked hole groups in the outer ring are connected by detonating cords and detonated simultaneously; After the pre-splitting hole group is detonated, the delay is t3; Then the slot hole group and the auxiliary hole group are detonated in reverse order from bottom to top according to the charge segmentation, with a delay of t2 between segments; In the same section, the slot hole group is detonated first, and then the auxiliary hole group is detonated. The auxiliary hole groups in each section are blasted layer by layer from the center to the outer circle. The same layer is detonated at the same time, and the delay between layers is t1; t3 is greater than t2, and t2 is greater than t1.

[0014] Optionally, the bottom of the pre-splitting hole group is reinforced with rock emulsion explosives, and the remaining part is continuously coupled with rock emulsion explosives; The cutout hole group and the auxiliary hole group use discontinuous non-coupled charging of rock emulsion explosives.

[0015] Optionally, during the blasting process, back pressure is applied to the openings of the blasting hole group located in the second middle section to seal the openings.

[0016] As described above, the underground mine branch chute blasting construction method of the present invention has at least the following beneficial effects: In view of the technical difficulties in the construction of branch chutes in underground mines, the blasting construction method provided by the present invention effectively overcomes the limitations of traditional construction methods by determining the axis of the branch chutes and combining scientific drilling and blasting strategies, and significantly improves the construction efficiency and quality. This method not only simplifies the construction process and reduces the construction difficulty, but also ensures the precise connection between the branch chutes and the main chutes, providing solid technical support for the safe and efficient mining of underground mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic diagram of the distribution of the main chute and branch chute of the present invention.

[0018] Figure 2 Shown is a schematic diagram of the blasting at the bottom of the branch chute of the present invention.

[0019] Figure 3 Shown is a schematic diagram of the blasting of the secondary bottom end of the branch chute of the present invention.

[0020] Figure 4 Shown is a schematic diagram of the bottom blasting of the branch chute of the present invention.

[0021] Figure 5 Shown is a schematic diagram of blasthole distribution according to the present invention.

[0022] Figure 6 Shown is another schematic diagram of blasthole distribution according to the present invention.

[0023] Figure 7 Shown are schematic diagrams of two blasthole charging modes of the present invention.

[0024] Figure 8 Schematic diagram showing the branch chute not aligned with the main chute (top view).

[0025] Among them: main chute 20, first middle section 21, second middle section 22, reference line 23, reference hole 24, filler 293, pre-splitting hole group 26, auxiliary hole group 27, groove hole group 28, center hole 280, surrounding hole 281, reinforced charge 290, continuous coupled charge 291, discontinuous uncoupled charge 292. DETAILED DESCRIPTION

[0026] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0027] See also Figures 1 to 8 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0028] The following embodiments are only for illustration purposes and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0029] For this example, please refer to Figure 1-Figure 4 The embodiment of the underground mine branch chute blasting construction method provided by the present invention comprises the following steps: Preparation step: according to the positions of the main chute 20, the first middle section 21 and the second middle section 22, the axis (design axis) of the branch chute is determined, and the branch chute connects the main chute 20 and the second middle section 22; Drilling steps: Take the axis (design axis) of the branch chute as the reference line 23, and drill the blasting hole group from the second middle section 22 to the main chute 20. During the formal drilling construction, ensure that the hole positioning, orientation, and hole length meet the requirements, the hole is well formed, and the hole wall is smooth. Choose skilled and highly skilled operators as much as possible; Blasting steps: fill the blasting charge into the blasting hole group and detonate, and the blasting debris falls into the main chute 20 to form a branch chute. Before blasting, clean up the wellhead debris, slag and gravel in advance. The length of each blast hole segmented charge is confirmed in advance to achieve the blasting section as flat as possible.

[0030] The middle section of an underground mine refers to the mining operation area divided at a certain height in the vertical direction during the mining process. These middle sections are connected to each other through tunnels, etc., which facilitates the transportation of personnel, equipment and ore, as well as ventilation, drainage and other operations.

[0031] The branch chute is used to transport the ore in the segment to the main chute 20. Since all structures are located underground, the relative positions of the main chute 20 and each middle section can be calculated according to the construction plan of the main chute 20 and each middle section in the prior art; or a three-dimensional structural model of the underground mine can be constructed using modeling tools in computer software to evaluate the relative positions of the main chute 20 and each middle section. Then, the branch chute is designed according to the relative position of the main chute 20 and each middle section. However, due to the limitations of the terrain and space of each middle section, it is difficult for large equipment to enter the middle section, and the construction of the branch chute is quite difficult.

[0032] In this embodiment, blasting construction is adopted, such as Figure 1 As shown, along the axis of the branch chute, multiple parallel holes are drilled from the second middle section 22 to the main chute 20, and then blasting cartridges are filled into the holes. The blasting cartridges are blasted section by section from the bottom of the main chute 20 to the top section at the second middle section 22. Figure 2-Figure 4 The blasting debris falls into the main chute 20 to form a branch chute.

[0033] The underground mine branch chute blasting construction method of the above-mentioned embodiment uses a blasting hole group drilled from the second middle section to the main chute for blasting construction, which effectively overcomes the construction difficulties caused by the terrain and space limitations in the middle section of the underground mine. This method does not require large equipment to enter the middle section, which reduces the construction difficulty and cost, while improving the construction efficiency. The branch chute is formed by blasting section by section, ensuring the safety and reliability of the construction. In addition, this method also makes full use of the existing structure of the main chute, realizes the automatic slag removal and transportation of blasting debris, and has a significant effect on improving the mining efficiency and construction safety of underground mines.

[0034] In this embodiment, in the preparation step, when determining (designing) the axis of the branch chute, the axis of the branch chute and the axis of the main chute 20 are located in the same plane, and this plane is used as the center plane. The axis of the branch chute and the axis of the main chute 20 are located in the same plane, that is, the axis of the branch chute intersects with the axis of the main chute 20, so that the two axes can determine this plane. In this way, when the wellbore of the branch chute is constructed with the axis of the branch chute, the wellbore of the branch chute can form a better centering relationship with the main chute, so that the outlet of the wellbore of the branch chute is located in the middle of the main chute, preventing the branch chute from being misaligned with the main chute.

[0035] Specifically, in order to make the axis of the branch chute intersect with the axis of the main chute 20 and be located in the same plane, it is necessary to know in advance the relative position relationship between the main chute 20 and the first middle section 21. This can be obtained based on the design drawings of the main chute 20 and the first middle section 21 combined with the actual construction adjustments. Computer simulation software can also be used to construct a three-dimensional data model inside the mine. The axis of the branch chute is designed on the model at the starting drilling position of the first middle section 21 and the drilling direction toward the main chute 20, and then the branch chute is constructed.

[0036] The above embodiment realizes the centering connection between the branch chute and the main chute by ensuring that the axis of the branch chute intersects and is coplanar with the axis of the main chute. This method uses design drawings or three-dimensional data models for precise planning, effectively avoiding the problem of misalignment during construction, ensuring that the outlet of the branch chute is precisely located in the middle of the main chute, and improving the efficiency of ore transportation. In addition, this technical solution also enhances the predictability and controllability of construction, reduces the difficulty and risk of construction, and provides an efficient, accurate and safe solution for the blasting construction of branch chutes in underground mines, which is of great significance to improving the overall benefits of mining.

[0037] This embodiment can be found in Figure 1 In the drilling step, when drilling the blast hole group, first drill a reference hole 24 along the axis (design axis) of the branch chute, and the reference hole 24 penetrates the soil from the second middle section 22 and enters the main chute 20. Measure the angle difference between the axis (actual construction axis) of the reference hole 24 and the center plane, adjust the drilling angle of the drilling equipment according to the angle difference, and then re-drill the reference hole 24 until the axis (actual construction axis) of the reference hole 24 is located in the center plane. Then, do not change the drilling angle of the drilling equipment, only translate the drilling equipment, and drill the remaining holes of the blast hole group parallel to the reference hole 24.

[0038] The center plane is an ideal design plane, which is determined by the axis of the main chute 20 and the reference hole 24. If the axis of the branch chute can be located on this plane during actual construction, the branch chute can form a better centering state with the main chute. Figure 8 , Figure 8 This is a top view. Due to the angle a of the branch chute axis deviation, the branch chute cannot be aligned with the main chute and even invades the wall of the main chute.

[0039] Although in the previous embodiment, we designed the axis of the branch chute to ensure that the branch chute can be aligned with the main chute 20, there are still errors in the positioning and orientation of the position and angle of the drilling rig during actual construction. Due to the long drilling depth, even at the starting end of the second middle section 22, the position or drilling angle of the drilling rig has only a very small deviation. When the drill rod is drilled out from the outlet end on one side of the main chute 20, a larger deviation may also occur. When the branch chute is formed by blasting and expanding the hole along the axis, the branch chute may not be aligned with the main chute 20. In extreme cases, if the axis is offset too much, the branch chute may also invade the side wall of the main chute 20, or even not intersect with the main chute 20.

[0040] The above-mentioned embodiment effectively solves the problem of cumulative deviation caused by small positioning or orientation errors during long-distance drilling by drilling and adjusting the reference hole to ensure that its actual axis is accurately located in the center plane defined by the axis of the main chute. After the axis of the reference hole is aligned, the remaining blasting holes are drilled based on the reference hole. This method significantly improves the centering accuracy of the branch chute and the main chute, avoids the risk of the branch chute deviating from the designed position or even invading the wall of the main chute, and ensures smooth and safe ore transportation. Through refined construction control and adjustment, this embodiment provides a more reliable technical path for the construction of branch chutes in underground mines, ensuring project quality and operating efficiency.

[0041] At the same time, during the drilling construction process of the above embodiment, a sampling drill can be used. During the drilling process, the soil layers along the drilling direction can be taken out, and these soil layer samples can be spliced ​​in sequence, so that the soil structure in each depth range from the drilling end of the second middle section 22 to the drilling end of the main chute 20 can be evaluated, and a detailed underground soil structure profile from the drilling end of the second middle section to the drilling end of the main chute is drawn for engineers. Through this profile, engineers can clearly identify different rock layers, broken zones, sand and other special structures in the soil, which has a vital guiding significance for the charge design in subsequent blasting operations.

[0042] In summary, the above construction method not only greatly improves the accuracy of the branch chute axis positioning, but also effectively reduces the risk of blasting caused by unknown soil structure. Engineers can finely design the charge amount at different locations according to the actual situation of the soil structure, so as to ensure that the blasting effect can meet the construction requirements without causing unnecessary damage to the surrounding structures. It not only improves the construction efficiency, but also shows significant beneficial effects in ensuring construction safety and reducing construction costs.

[0043] For this example, please refer to Figure 5 and Figure 6 . Figure 5 and Figure 6In order to illustrate the distribution of each hole group, when using numbers, the numbers are indicated on the connecting line of the same hole group. The blasting hole group includes a pre-splitting hole group 26, an auxiliary hole group 27 and a slotting hole group 28; The pre-splitting hole group 26 is distributed at the outermost periphery of the blasting hole group; The slotting hole group 28 is distributed in the central area of ​​the blasting hole group, including the central hole 280 and the surrounding holes 281 surrounding the central hole 280. The blasting effect is closely related to the slotting method. The slotting blasting method is mainly divided into two categories: oblique slotting and straight slotting. The oblique slotting is often limited by the size of the construction section. The smaller the construction section, the more unfavorable it is to use the oblique slotting and the mechanized operation of the workers. Therefore, the slotting method selects the parallel empty hole straight hole slotting in the straight slotting; The auxiliary hole group 27 is located between the pre-splitting hole group 26 and the slotting hole group 28. The auxiliary hole group 27 is arranged in layers. Figure 5 The case with three layers of auxiliary hole groups 27 is shown. Figure 6 The case where there are two layers of auxiliary hole groups 27 is shown.

[0044] The selection of blasthole diameter should take into account the size of the cross section, the size of the broken pieces, the capacity of the rock drilling tool and other factors, such as the drilling speed, blasting economy, actual conditions on site, and the existing drilling rig model.

[0045] The branch chute blasting construction adopts a blasting strategy that combines pre-splitting hole groups, auxiliary hole groups and slotting hole groups. The pre-splitting hole group is located at the outermost periphery and is responsible for controlling the blasting contour; the slotting hole group is located in the center to increase the free surface; the auxiliary hole group is located between the two, layered and expanded layer by layer. During construction, the pre-splitting hole group is first detonated to form a preliminary contour, followed by the slotting hole group blasting to increase the internal space, and finally the auxiliary hole group is detonated layer by layer to transmit and expand the blasting effect to the surrounding areas to ensure the smooth excavation of the branch chute.

[0046] This implementation method effectively improves the accuracy and safety of branch chute blasting construction through fine blasting hole group design and layer-by-layer detonation strategy. The pre-splitting hole group ensures the regularity of the excavation contour, and the combination of the slot hole group and the auxiliary hole group greatly improves the blasting efficiency and ensures the shape of the hole wall. In addition, the layer-by-layer jump section micro-difference arrangement further ensures the uniform transmission of the blasting effect, reduces the interference with the surrounding environment, and realizes efficient and safe blasting construction.

[0047] Furthermore, the spacing and number of holes can be calculated based on the design size of the branch chute, the blasting stress wave crack circle theory, and the supplementary space theory. In one possible implementation, the slotted hole group 28 is located in the central area of ​​the area surrounded by the pre-cracked hole group 26, and at least one layer of auxiliary hole group 27 surrounds the slotted hole group 28 in a ring shape. Figure 5 As shown; Or, the cutout hole group 28 is biased toward one side of the area surrounded by the pre-splitting hole group 26, and at least one layer of auxiliary hole group 27 surrounds the cutout hole group 28 in an arc shape, such as Figure 4 When this method is implemented, the slot hole group 28 can be biased towards the main chute, that is, the main chute has fewer auxiliary hole groups 27, so that this side is less affected during blasting. Especially at the connection end of the branch chute and the main chute, that is, Figure 2 The P area shown is subjected to a small blasting force, thus preventing the blasting force from collapsing the main chute.

[0048] The above implementation method significantly optimizes the effect of branch chute blasting construction by flexibly adjusting the position of the slot hole group. When the slot hole group is biased toward one side of the area enclosed by the pre-splitting hole group, the number of auxiliary hole groups on one side of the main chute can be reduced, thereby reducing the blasting impact in this area. Especially at the connection end between the branch chute and the main chute, this layout can significantly reduce the impact of the blasting force on this area and effectively avoid damage to the main chute structure. It not only improves the safety of blasting construction, but also ensures the integrity of the main chute structure, providing a strong guarantee for safe and efficient mining in underground mines.

[0049] Furthermore, in this embodiment, during the blasting step, when filling the blasting cartridge: The central hole 280 of the cutout hole group 28 is charged according to the first mode, and the surrounding holes 281 are left empty and not charged; The auxiliary hole group 27 is also charged according to the first mode; The pre-splitting hole group 26 is charged according to the second mode; The first mode of charging refers to charging in sections along the axis of the hole, with fillers 293 set between sections. The filling adopts a mixed filling of "gun mud + sand and stone". The sand and stone are measured in advance according to the filling height and filled according to the designed length. The second mode of charging refers to charging in whole sections along the axis of the hole.

[0050] Since all holes have been drilled through, direct charging will leak into the main chute from the bottom of the hole. Therefore, it is necessary to use a thin rope to lower a small wooden board to "re-seal" the bottom of the charging hole. The small wooden board at the lower end of the thin rope is lowered to the bottom of the hole to form a bottom support structure. The upper end of the thin rope is fixed at the hole mouth. After the bottom of the hole is filled for 0.5m, charging begins. The main function of the pre-crack hole group 26 is to form the outline of the branch chute. By charging along the entire section of the axis of the hole, the entire branch chute rock mass can be disconnected from the surrounding rock mass or cracked; the central hole 280 of the groove hole group 28 is charged according to the first mode, and the peripheral surrounding holes 281 are left empty and uncharged. When the central hole 280 is detonated, under the action of the peripheral surrounding holes 281, a fracture surface can be formed along the peripheral surrounding holes 281, so that an air-facing surface is formed in the central part. When the auxiliary hole group 27 is detonated layer by layer toward the periphery, it is blasted outward layer by layer with the groove area as the center, which plays a role in transmitting and expanding the blasting effect.

[0051] Specifically, in the blasting step, when blasting: The pre-crack hole group 26 of the outer ring is connected by a detonating cord and detonated at the same time, and the detonation time can be recorded as time 0; After the pre-splitting hole group 26 is detonated, the delay t3 may be 100 milliseconds; Then, the cutout hole group 28 and the auxiliary hole group 27 are detonated in reverse from bottom to top according to the charge segmentation, and the delay t2 between segments can be 500 milliseconds; In the same section, the slot hole group 28 is detonated first, with a delay of t1, and then the auxiliary hole group 27 is detonated. The auxiliary hole group 27 in each section is detonated layer by layer from the center to the outer circle, and the same layer is detonated at the same time. The delay t1 between layers can be 100 milliseconds; t3 is greater than t2, and t2 is greater than t1.

[0052] More specifically, the detonation time of the outer ring pre-splitting hole group 26 is recorded as time 0. Combined with the figure, the detonation time of the center hole 280 in the lowest section (close to one end of the main chute) can be 100 milliseconds, the detonation time of the inner ring auxiliary hole group 27 is 200 milliseconds, the detonation time of the middle ring auxiliary hole group 27 is 300 milliseconds, and the detonation time of the outer ring auxiliary hole group 27 is 400 milliseconds. The end state is as follows Figure 2 After a delay of 500 milliseconds, the previous section begins to be detonated. The detonation time of the center hole 280 is 900 milliseconds, the detonation time of the inner circle auxiliary hole group 27 is 100 milliseconds, the detonation time of the middle circle auxiliary hole group 27 is 1100 milliseconds, and the detonation time of the outer circle auxiliary hole group 27 is 1200 milliseconds. The end state is as follows Figure 3 ; Then start detonating the previous section, and so on, until all the detonations are completed.

[0053] The blasting technology of the above-mentioned implementation method significantly improves the blasting efficiency and safety through the refined charging mode and detonation sequence design. The whole-section charging of the pre-crack hole ensures the accurate formation of the branch chute contour, while the segmented charging and delayed detonation strategy of the slot hole and the auxiliary hole effectively utilizes the stress wave transmission effect of the rock, realizing layer-by-layer blasting from the inside to the outside, which not only increases the blasting range, but also reduces unnecessary damage to the surrounding rock mass. In addition, the reasonable delay setting ensures the orderly connection of each blasting area, improves the coordination and controllability of the overall blasting operation, and provides an efficient and safe solution for the construction of mine branch chutes under complex geological conditions.

[0054] For further information, see Figure 7 , Figure 7 The left side shows the charging pattern of the pre-splitting hole group 26. The bottom of the pre-splitting hole group 26 uses a rock emulsion explosive reinforced charge 290, and the rest of the pre-splitting hole group 26 uses a rock emulsion explosive continuous coupling charge 291; Figure 7This is the charging pattern of the slot hole group 28 and the auxiliary hole group 27 . The slot hole group 28 and the auxiliary hole group 27 use discontinuous non-coupled charging 292 of rock emulsion explosive.

[0055] When charging, the detonating cord and the detonator leg wire are directly installed together with the charge roll. Double detonators and detonating cords are placed on each layer of charge roll to prevent explosion rejection. The detonating cord and the detonator leg wire are pressed under the charge roll to reduce the volume and ensure that the charge structure can be lowered smoothly in the hole wall. This implementation method significantly improves the blasting effect by optimizing the charging pattern. The reinforced charge at the bottom of the pre-splitting hole group enhances the energy release in the initial stage of blasting, which helps to accurately form the outline of the branch chute; while the continuous coupling charge ensures the uniform transmission of blasting energy. The discontinuous non-coupled charge is used in the slot hole group and the auxiliary hole group, which not only controls the blasting power, but also reduces the damage to the surrounding rock mass, achieving the dual goals of efficient blasting and construction safety. It provides a safer and more efficient solution for the blasting construction of underground mine branch chutes.

[0056] In this embodiment, during the blasting process, some blast holes were punched. It was analyzed that the energy from the first layer of blasting could not be completely blocked, which resulted in the filling interval and the second layer of explosive packs being pushed upward as a whole. Therefore, the opening of the blasting hole group located in the second middle section 22 was back-pressured to block the opening. One of the simpler implementation methods is to cover the holes of the blasting hole group with wooden boards and place heavy objects such as sandbags on top of the template. According to the experience of the test explosion, heavy objects such as sandbags are used to back-pressure the opening to prevent punching, reduce the leakage of explosive energy, and optimize the blasting effect.

[0057] In summary, the present invention effectively overcomes various shortcomings in the prior art, can produce beneficial technical effects, and has significant progress.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for blasting a branch chute in an underground mine, characterized in that: The following steps are involved: Preparation step: determining the axis of the branch chute according to the positions of the main chute (20), the first middle section (21) and the second middle section (22), wherein the branch chute connects the main chute (20) and the second middle section (22); Drilling step: using the axis of the branch chute as a reference line (23), drilling a blasting hole group from the second middle section (22) toward the main chute (20); Blasting step: filling the blasting cartridges into the blasting hole group and detonating them, so that the blasting debris falls into the main chute (20) to form a branch chute.

2. The underground mine branch chute blasting construction method according to claim 1, characterized in that: In the preparation step, when determining the axis of the branch chute, the axis of the branch chute and the axis of the main chute (20) are located in the same plane, and this plane is used as the central plane.

3. The underground mine branch chute blasting construction method according to claim 2, characterized in that: In the drilling step, when drilling the blasting hole group, a reference hole (24) is first drilled along the axis of the branch chute, the reference hole (24) penetrates the soil from the second middle section (22) and enters the main chute (20), the angle difference between the axis of the reference hole (24) and the center plane is measured, the drilling angle of the drilling equipment is adjusted according to the angle difference, and the reference hole (24) is re-drilled until the axis of the reference hole (24) is located in the center plane.

4. The underground mine branch chute blasting construction method according to claim 3, characterized in that: The drilling angle of the drilling equipment is not changed, and the drilling equipment is only translated to drill the remaining holes of the blasting hole group parallel to the reference hole (24).

5. The underground mine branch chute blasting construction method according to claim 4, characterized in that: The blasting hole group comprises a pre-splitting hole group (26), an auxiliary hole group (27) and a slotting hole group (28); The pre-splitting hole group (26) is distributed at the outermost periphery of the blasting hole group; The cutout hole group (28) is distributed in the central area of ​​the blasting hole group, and includes a central hole (280) and surrounding holes (281) surrounding the central hole (280); The auxiliary hole group (27) is located between the pre-splitting hole group (26) and the slotting hole group (28), and the auxiliary hole group (27) is arranged in layers.

6. The underground mine branch chute blasting construction method according to claim 5, characterized in that: The groove hole group (28) is located in the central area of ​​the area enclosed by the pre-splitting hole group (26), and at least one layer of the auxiliary hole group (27) surrounds the groove hole group (28) in a ring shape; Alternatively, the groove hole group (28) is biased toward one side of the area enclosed by the pre-splitting hole group (26), and at least one layer of the auxiliary hole group (27) surrounds the groove hole group (28) in an arc shape.

7. The underground mine branch chute blasting construction method according to claim 5, characterized in that: In the blasting step, when filling the blasting charge: The central hole (280) of the cutout hole group (28) is charged according to a first mode, and the surrounding holes (281) are left empty and not charged; The auxiliary hole group (27) is also charged according to the first mode; The pre-splitting hole group (26) is charged according to a second mode; The first mode of charging refers to charging in sections along the axis of the hole, with fillers (293) arranged between the sections; the second mode of charging refers to charging in whole sections along the axis of the hole.

8. The underground mine branch chute blasting construction method according to claim 7, characterized in that: In the blasting step, during blasting: The pre-crack hole groups (26) of the outer ring are connected by detonating cords and detonated simultaneously; After the pre-splitting hole group (26) is detonated, a delay of t3 is applied; Then, the cutout hole group (28) and the auxiliary hole group (27) are detonated in reverse order from bottom to top according to the charge segmentation, with a delay of t2 between segments; In the same section, the slot hole group (28) is detonated first, and then the auxiliary hole group (27) is detonated. The auxiliary hole group (27) in each section is detonated layer by layer from the center to the outer circle. The same layer is detonated at the same time, and the delay between layers is t1; t3 is greater than t2, and t2 is greater than t1.

9. The underground mine branch chute blasting construction method according to claim 7, characterized in that: The bottom of the pre-splitting hole group (26) is reinforced with rock emulsion explosive (290), and the remaining part is continuously coupled with rock emulsion explosive (291); The cutout hole group (28) and the auxiliary hole group (27) use discontinuous non-coupled charges (292) of rock emulsion explosives.

10. The underground mine branch chute blasting construction method according to claim 1, characterized in that: During the blasting process, back pressure is applied to the openings of the blasting hole group located in the second middle section (22) to seal the openings.

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