Method for rapid removal of intermediate bridge and recovery of coal in coal bench based on cast blasting

Abstract

20 25 27 98 35 15 D ec 2 02 5 A B S T R A C T 2 0 2 5 2 7 9 8 3 5 1 5 D e c 2 0 2 5 A B S T R A C T 2 0 2 5 2 7 9 8 3 5 1 5 D e c 2 0 2 5 1 DRAWINGS 1 / 4 FIG. 1 3 421 FIG. 2 DRAWINGS 1 / 4 Break and cast, by cast blasting, a material in a primary bridge body removal S1 area, and handle a remaining blast pile and a material requiring separate handling in the primary bridge body removal area after the cast blasting Mine the primary coal bench mining area to extract coal in the primary coal S2 bench mining area Break and cast, by cast blasting, a material in a secondary bridge body S3 removal area, and handle a remaining blast pile and a material requiring separate handling in the secondary bridge body removal area after the cast blasting Mine the secondary coal bench mining area to extract coal in the secondary S4 coal bench mining area FIG. 1 1 2 3 4 FIG. 2 1 20 25 27 98 35 15 D ec 2 02 5 1 / 4 2 0 2 5 2 7 9 8 3 5 1 5 D e c 2 0 2 5 S 2 S 4 F I G . 1 2 3 4 F I G . 2 1 1 / 4 2 0 2 5 2 7 9 8 3 5 1 5 D e c 2 0 2 5 S 2 S 4 F I G . 1 2 3 4 F I G . 2 1

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of open-pit coal mining, and in particular to a method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting. BACKGROUND

[0002] In the related art, when coal mining operations reach the intermediate bridge, the bridge body of the intermediate bridge is imminent for removal to extract the coal under the bridge body. The existing secondary stripping process mainly includes two tasks: drilling and blasting, and bench lowering and loading-hauling. During construction, to ensure safety, drilling and blasting are first carried out at the coal-rock interface to prepare for secondary stripping. Then front-end loaders or bulldozers are used for bench lowering operations, followed by full loading and hauling of the secondary stripping materials until the raw coal bench is completely exposed. However, when the bridge body is removed with this method, the number of simultaneously operating loading and hauling equipment units is limited. Consequently, the efficiency of secondary stripping cannot be fully exerted, resulting in prolonged bridge removal and delayed bridge cut-through, thereby affecting the function of the intermediate bridge as a transportation channel connecting the stope and the internal dump. In addition, the materials above the raw coal bench must be fully loaded and hauled, leading to a large workload for secondary stripping. SUMMARY

[0003] The present disclosure aims to at least partially solve one of the technical problems in the related art. To this end, a first objective of the present disclosure is to propose a method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting. The present disclosure can solve the problems of large workload for secondary stripping and low efficiency of intermediate bridge removal. Therefore, the present disclosure can reduce the workload for secondary stripping, shorten the time of intermediate bridge removal, accelerate the cut-through of the intermediate bridge, and ensure the function of the intermediate bridge as a transportation channel connecting a stope to an internal dump.

[0004] In order to achieve the above objective, an embodiment in a first aspect of the present disclosure proposes a method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting, where the intermediate bridge includes an intermediate 2025279835   15 Dec 2025 bridge reserved area and a bridge body removal area; one side of the intermediate bridge reserved area is connected to an internal dump, and one side of the bridge body removal area is connected to the coal bench; the bridge body removal area is divided into a primary bridge body removal area and a secondary bridge body removal area; the coal bench is located beneath the bridge body removal area; the coal bench refers to coal formed beneath a bridge body, and the coal bench is divided into a primary coal bench mining area and a secondary coal bench mining area; and the method for the rapid removal of the intermediate bridge and the recovery of the coal includes: breaking and casting, by the cast blasting, a material in the primary bridge body removal area, and handling a remaining blast pile and a material requiring separate handling in the primary bridge body removal area after the cast blasting; mining the primary coal bench mining area to extract coal in the primary coal bench mining area; breaking and casting, by the cast blasting, a material in the secondary bridge body removal area, and handling a remaining blast pile and a material requiring separate handling in the secondary bridge body removal area after the cast blasting; and mining the secondary coal bench mining area to extract coal in the secondary coal bench mining area.

[0005] In the method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to the embodiment of the present disclosure, the bridge body removal area is divided into the primary bridge body removal area and the secondary bridge body removal area. The coal bench is divided into the primary coal bench mining area and the secondary coal bench mining area. First, the primary bridge body removal area is removed, then the primary coal bench mining area is mined, then the secondary bridge body removal area is removed, and finally the secondary coal bench mining area is mined. The method breaks and casts the material in the bridge body removal area by cast blasting, thereby dispersing the material in the bridge body removal area. On the one hand, the material of the intermediate bridge and the material at the goaf are stripped simultaneously, shortening the bridge removal time and advancing the bridge cut-through. On the other hand, the vast space of the goaf is fully utilized in conjunction with the storage of the secondary stripping material, reducing the secondary stripping workload in the bridge body removal area and saving the secondary stripping cost.

[0006] In addition, the method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to the embodiment of the present disclosure may further have the following additional technical features:

[0007] According to an embodiment of the present disclosure, the method includes: handling, by a single-bucket - truck process, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting, and the remaining blast 2025279835   15 Dec 2025 pile and the material requiring separate handling in the secondary bridge body removal area after the cast blasting.

[0008] According to an embodiment of the present disclosure, the handling, by the single-bucket - truck process, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting and the remaining blast pile and the material requiring separate handling in the secondary bridge body removal area after the cast blasting includes: transporting, by single-bucket excavator loading and truck haulage, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting, and the remaining blast pile and the material requiring separate handling in the secondary bridge body removal area after the cast blasting to the internal dump for dumping.

[0009] According to an embodiment of the present disclosure, an effectively cast material in the primary bridge body removal area after the cast blasting and an effectively cast material in the secondary bridge body removal area after the cast blasting are temporarily stored in a goaf.

[0010] According to an embodiment of the present disclosure, a boundary between the intermediate bridge reserved area and the bridge body removal area is determined according to a natural repose angle of a material of the intermediate bridge during secondary stripping.

[0011] According to an embodiment of the present disclosure, during hole drilling and installation of an explosive charge for the cast blasting, an inclination angle of a blast hole for the cast blasting follows a principle of consistency with a bench slope angle and a principle of minimum burden.

[0012] According to an embodiment of the present disclosure, during the cast blasting, a material casting direction is a direction toward the goaf at two sides of the intermediate bridge.

[0013] According to an embodiment of the present disclosure, a boundary between the primary bridge body removal area and the secondary bridge body removal area is determined according to a natural repose angle of a material in the bridge body removal area.

[0014] According to an embodiment of the present disclosure, the coal bench is divided into the primary coal bench mining area and the secondary coal bench mining area according to a sequence of coal exposure of the coal bench.

[0015] A part of additional aspects and advantages of the present disclosure is provided in the following descriptions, and the part will become apparent from the following descriptions, or may be learned from the practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a flowchart of a method for rapid removal of an intermediate bridge and 2025279835   15 Dec 2025 recovery of coal in a coal bench based on cast blasting according to an embodiment of the present disclosure;

[0017] FIG. 2 is a schematic view of a bridge body removal area of the intermediate bridge according to an embodiment of the present disclosure;

[0018] FIG. 3 is a top view of a bridge body and a coal bench when the intermediate bridge is cut through according to an embodiment of the present disclosure;

[0019] FIG. 4 is a top view of the bridge body and the coal bench when removal is imminent according to an embodiment of the present disclosure;

[0020] FIG. 5 is a top view of the bridge body and the coal bench after primary removal of the bridge body according to an embodiment of the present disclosure;

[0021] FIG. 6 is a top view of the bridge body and the coal bench after primary coal mining according to an embodiment of the present disclosure;

[0022] FIG. 7 is a top view of the bridge body and the coal bench after secondary removal of the bridge body according to an embodiment of the present disclosure;

[0023] FIG. 8 is a front view of the division of the bridge body removal area according to an embodiment of the present disclosure;

[0024] FIG. 9 is a front view of the bridge body after the primary removal according to an embodiment of the present disclosure;

[0025] FIG. 10 is a front view of the bridge body after the secondary removal according to an embodiment of the present disclosure;

[0026] FIG. 11 is a schematic view of a primary bridge body removal area after cast blasting according to an embodiment of the present disclosure; and

[0027] FIG. 12 is a schematic view of a secondary bridge body removal area after cast blasting according to an embodiment of the present disclosure.

[0028] Reference Numerals:

[0029] 1. internal dump; 2. intermediate bridge reserved area;

[0030] 3. bridge body removal area; 31. primary bridge body removal area; 32. secondary bridge body removal area;

[0031] 4. coal bench; 41. primary coal bench mining area; 42. secondary coal bench mining area;

[0032] 5. upper coal bench slope top line; 6. upper coal bench slope bottom line; 7. lower coal bench slope top line; 8. lower coal bench slope bottom line; 9. intermediate bridge slope top line; 10. intermediate bridge pit slope bottom line; 11. intermediate bridge transportation platform; 12. upper coal bench-intermediate bridge slope bottom line; 13. coal bench boundary line;

[0033] 141. effectively cast material of primary bridge body removal area after cast blasting; 2025279835   15 Dec 2025 142. effectively cast material of secondary bridge body removal area after cast blasting;

[0034] 151. material requiring separate handling of primary bridge body removal area after cast blasting; 152. material requiring separate handling of secondary bridge body removal area after cast blasting. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The embodiments of the present disclosure are described below in detail. Examples of the embodiments are shown in the drawings. The same or similar numerals represent the same or similar elements or elements having the same or similar functions throughout the specification. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present disclosure but should not be construed as a limitation to the present disclosure.

[0036] A method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting proposed by an embodiment of the present disclosure is described below with reference to the drawings.

[0037] FIG. 1 is a flowchart of a method for rapid removal of an intermediate bridge and recovery of coal in the coal bench based on cast blasting according to an embodiment of the present disclosure.

[0038] In an embodiment of the present disclosure, as shown in FIGS. 2 to 12, the intermediate bridge includes an intermediate bridge reserved area 2 and a bridge body removal area 3. One side of the intermediate bridge reserved area 2 is connected to an internal dump 1, and one side of the bridge body removal area 3 is connected to a coal bench 4. The bridge body removal area 3 is divided into a primary bridge body removal area 31 and a secondary bridge body removal area 32. The coal bench 4 is located beneath the bridge body removal area 3. The coal bench 4 refers to coal bench formed beneath a bridge body, and the coal bench 4 is divided into a primary coal bench mining area 41 and a secondary coal bench mining area 42.

[0039] Specifically, the intermediate bridge refers to a bridge constructed to connect a stope to the internal dump 1, thereby shortening the transportation distance. The intermediate bridge is a dynamic bridge formed of a stripping material from an open-pit mine in the early stage of its service and unmined coal in the later stage, starting from the beginning of its use until the point where the material of the bridge body transitions into coal. As shown in FIG. 2, the internal dump 1, the intermediate bridge reserved area 2, the bridge body removal area 3, and the coal bench 4 are arranged from left to right. In the embodiment of the present disclosure, the bridge body removal area 3 is divided into the primary bridge body removal area 31 and the secondary bridge body removal area 32 to demolish the bridge body removal area 3 in two stages. The coal 2025279835   15 Dec 2025 bench 4 is divided into the primary coal bench mining area 41 and the secondary coal bench mining area 42 to extract the coal at the coal bench 4 in two stages.

[0040] As shown in FIG. 1, the method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting according to the embodiment of the present disclosure includes the following steps.

[0041] S1. The material in the primary bridge body removal area 31 is broken and cast by cast blasting, and a remaining blast pile and a material requiring separate handling of the primary bridge body removal area 31 after cast blasting are handled.

[0042] S2. The primary coal bench mining area 41 is mined to extract the coal in the primary coal bench mining area 41.

[0043] S3. The material in the secondary bridge body removal area 32 is broken and cast by cast blasting, and a remaining blast pile and a material requiring separate handling of the secondary bridge body removal area 32 after cast blasting are handled.

[0044] S4. The secondary coal bench mining area 42 is mined to extract the coal in the secondary coal bench mining area 42.

[0045] Specifically, cast blasting is a technology of using explosive blasting energy to crush rocks and cast a part of the stripping material into a goaf, which greatly reduces the operation cost of stripping equipment. The cast blasting technology can reduce the height of the stripping bench. For example, an original 30 m high bench is lowered to a height of about 20 m after blasting. The removal process of the intermediate bridge is actually a process of recovering the coal beneath the bridge body. During the removal process, according to the equipment layout requirements, the rocks at a coal-rock interface of the bridge body are first cleared. Since these rocks are piled up with the stripping material during bridge construction, clearing these rocks is also called secondary stripping. After secondary stripping, the recovery of coal beneath the bridge body begins.

[0046] Specifically, first, the primary bridge body removal area 31 is blasted through the cast blasting technology. By controlling blasting energy and blasting direction, the primary bridge body removal area 31 is broken and cast to a designated area (goaf). After blasting, for the remaining blast pile (i.e., piled material after blasting) and the material requiring separate handling (which may refer to some large materials or special areas, etc.) in the primary bridge body removal area 31, a single-bucket - truck process is adopted for clearing and transportation, and these materials are transported to the internal dump 1 for dumping, as shown in FIGS. 5, 9, and 11.

[0047] After the primary bridge body removal area 31 is cleared, equipment such as an excavator or a shearer is used to mine the primary coal bench mining area 41 in accordance with 2025279835   15 Dec 2025 normal coal mining procedures and operating parameters. The mined coal is transported to a designated location by a truck until the coal mining in the primary coal bench mining area 41 is completed, as shown in FIG. 6.

[0048] The secondary bridge body removal area 32 is blasted through the cast blasting technology. By controlling blasting energy and blasting direction, the secondary bridge body removal area 32 is broken and cast to the goaf. After blasting, for a remaining blast pile and a material requiring separate handling in the secondary bridge body removal area 32, the single-bucket - truck process is adopted for clearing and transportation, and materials are transported to the internal dump 1 for dumping, as shown in FIGS. 7, 10 and 12.

[0049] After the secondary bridge body removal area 32 is cleared, equipment such as an excavator or a shearer is used to mine the secondary coal bench mining area 42 in accordance with normal coal mining procedures and operating parameters. The mined coal is transported to a designated location by a truck until the coal mining in the secondary coal bench mining area 42 is completed and the coal bench 4 is fully extracted, thereby completing the recovery of coal.

[0050] It should be understood that the removal of the intermediate bridge is imminent in the following situation. Due to the coal bench 4 beneath the bridge body removal area 3, when the coal mining operation reaches an intermediate bridge pit slope bottom line 10, it becomes difficult to extract the coal bench 4 beneath the bridge body, and the bridge body of the intermediate bridge begins to face removal problems, as shown in FIG. 4.

[0051] It should be noted that for ease of understanding, an upper coal bench slope top line 5, an upper coal bench slope bottom line 6, a lower coal bench slope top line 7, a lower coal bench slope bottom line 8, an intermediate bridge slope top line 9, the intermediate bridge pit slope bottom line 10, an intermediate bridge transportation platform 11, an upper coal bench-intermediate bridge slope bottom line 12, and a coal bench boundary line 13 are marked in top views of FIGS. 2 to 6 of the present disclosure.

[0052] Thus, the method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting according to the embodiment of the present disclosure breaks and casts the material in the bridge body removal area 3 by cast blasting. About 1 / 3 of the material is transferred to the goaf at two sides of the intermediate bridge to disperse the material from the bridge body removal area 3. On the one hand, the material of the intermediate bridge and the material at the goaf can be stripped simultaneously by increasing the number of simultaneously operating loading and hauling equipment units, giving full play to the efficiency of secondary stripping. This shortens the bridge removal time, advances the bridge cut-through, and ensures the function of the intermediate bridge as a transportation channel connecting the stope to the internal dump 1. On the other hand, the goaf is used for temporary or long-term 2025279835   15 Dec 2025 storage of the material. The vast space of the goaf is fully combined with the storage of secondary stripping material, most of the material far from the coal bench 4 after casting is left in the goaf, and only a small part of the material still pressing a slope toe after casting is stripped. This reduces the secondary stripping workload in the bridge body removal area 3 and saves the secondary stripping cost.

[0053] According to an embodiment of the present disclosure, the single-bucket - truck process is adopted to handle the remaining blast pile and the material requiring separate handling in the primary bridge body removal area 31 and those in the secondary bridge body removal area 32 after cast blasting. The distribution of the material requiring separate handling 151 of the primary bridge body removal area after cast blasting is shown in FIG. 11, and the distribution of the material requiring separate handling 152 of the secondary bridge body removal area after cast blasting is shown in FIG. 12.

[0054] Furthermore, according to an embodiment of the present disclosure, the single-bucket -truck process is adopted to handle the remaining blast pile and the material requiring separate handling in the primary bridge body removal area 31 and those in the secondary bridge body removal area 32 after cast blasting as follows. The remaining blast pile and the material requiring separate handling in the primary bridge body removal area 31 and those in the secondary bridge body removal area 32 after cast blasting are transported to the internal dump 1 for dumping by means of single-bucket excavator loading and truck haulage.

[0055] Specifically, the single-bucket - truck process involves the use of single-bucket excavators for loading and trucks for transporting the material in the mining operation of the open-pit coal, which can cope with different terrains and materials. When the single-bucket excavator is used for loading operations in the primary bridge body removal area 31 and the secondary bridge body removal area 32 after cast blasting, a bucket of the excavator is inserted into the remaining blast pile, and the broken stones, earthwork or other materials generated by blasting are loaded into the bucket. For large stones or irregularly shaped materials, i.e., the material requiring separate handling, further breaking or decomposition is performed to ensure that they can be effectively loaded onto the truck. After loading is completed, the truck is driven to a side of the excavator. The excavator unloads the material in the bucket into a truck bed, and the truck is then driven to the designated internal dump 1 to dump the material.

[0056] According to an embodiment of the present disclosure, an effectively cast material of the primary bridge body removal area 31 and an effectively cast material of the secondary bridge body removal area 32 after cast blasting are temporarily stored in the goaf.

[0057] Specifically, the distribution of the effectively cast material 141 of the primary bridge body removal area after cast blasting is shown in FIG. 11, and the distribution of the effectively 2025279835   15 Dec 2025 cast material 142 of the secondary bridge body removal area after cast blasting is shown in FIG. 12. The bottom of the open-pit mine has a large area of goaf, providing a vast space for temporary or long-term storage of the material. Therefore, the effective integration of the vast space of the goaf with the transfer of the secondary stripping material allows simultaneous stripping of the material of the intermediate bridge and the material at the goaf. It improves the loading and hauling efficiency of the secondary stripping material and shortens the removal time of the intermediate bridge. In addition, storing the material far from the bench in the goaf reduces the stripping workload.

[0058] According to an embodiment of the present disclosure, a boundary between the intermediate bridge reserved area 2 and the bridge body removal area 3 is determined according to a natural repose angle of a material of the intermediate bridge during secondary stripping.

[0059] Specifically, the intermediate bridge reserved area 2 refers to a part that still needs to be reserved during secondary stripping, while the bridge body removal area 3 refers to a part that needs to be removed. The boundary between these two areas is very important because it determines which material needs to be removed and which can be retained. The natural repose angle, also known as a natural slope of repose or internal friction angle, refers to a maximum stable angle formed by natural accumulation of the material without external force. When the material is piled to a certain height, due to its own gravity and internal friction, a stable angle preventing the material from collapsing spontaneously is formed, which is the natural repose angle. Different materials have different natural angles of repose. For example, the natural repose angle of dry sand is approximately 30° to 35°.

[0060] The significance of considering the natural repose angle when determining the boundary between the intermediate bridge reserved area 2 and the bridge body removal area 3 lies in the following aspects. Stability: The material of the intermediate bridge reserved area 2 needs sufficient stability to support the upper structure and vehicle traffic, and the natural repose angle can help determine the maximum safe angle for material stacking. Economy: By reasonably determining the boundary, unnecessary material movement can be reduced, and mining costs can be lowered. Safety: Slope landslides or other safety accidents caused by excessive stripping or improper material stacking can be avoided. Resource recovery: It ensures that valuable coal resources can be maximally recovered during the removal process, and waste materials can be properly handled.

[0061] According to an embodiment of the present disclosure, during hole drilling and installation of an explosive charge for the cast blasting, an inclination angle of a blast hole for cast blasting follows a principle of consistency with a bench slope angle and a principle of minimum burden. 2025279835   15 Dec 2025

[0062] Specifically, the bench slope angle refers to an angle between a bench slope and a horizontal plane, which is usually 65° to 70°. In cast blasting, the inclination angle of the blast hole should be consistent with the bench slope angle to ensure that the blasting force can effectively cast the rock to the expected area. This consistency can maximize the use of blasting energy to achieve effective rock casting and reduce damage to the surrounding environment.

[0063] The burden refers to a shortest distance from a bottom of the blast hole to a free face (i.e., a face where the rock can move freely after blasting). In cast blasting, the minimum burden principle states that the explosive in the blast hole should be disposed at a position where the burden is minimized, such that the blasting energy can act on the rock in a concentrated manner, thereby improving blasting efficiency. Optimizing the position and depth of the explosive charge can ensure the effective transfer of the blasting energy and the smooth casting of the rock.

[0064] In practical operations, these two principles usually need to be considered in combination. The setting of the inclination angle of the blast hole should not only consider the bench slope angle to ensure the effective use of the blasting energy but also consider the minimum burden to improve the efficiency and effect of blasting. Such a design can ensure the safety and economy of blasting operations and minimize environmental impact. It should be noted that during blasting operations, relevant safety regulations and standards must be followed, such as the provisions in the "Safety Regulations for Blasting" (GB6722-2011, People's Republic of China), to ensure the safety of blasting operations.

[0065] According to an embodiment of the present disclosure, during cast blasting, a material casting direction is a direction toward the goaf at two sides of the intermediate bridge.

[0066] Specifically, during cast blasting operations, by reasonably designing the casting distance, direction, and material distribution, the blasted material can fall into the goaf as expected, thereby effectively utilizing the existing space and reducing the occupation of new land. The design can also reduce the impact on the surrounding environment, lower the potential risks of blasting operations to the surrounding environment and personnel safety, and improve the safety of blasting. The material cast into the goaf can be recovered and processed subsequently. For example, waste rocks can be recycled or used as a filling material, thereby reducing mining costs and reducing damage to the natural environment, in compliance with environmental protection requirements.

[0067] According to an embodiment of the present disclosure, the boundary between the primary bridge body removal area 31 and the secondary bridge body removal area 32 is determined according to the natural repose angle of the material in the bridge body removal area 3.

[0068] Specifically, the boundary between the primary bridge body removal area 31 and the 2025279835   15 Dec 2025 secondary bridge body removal area 32 is determined based on the natural repose angle of the material, combined with blasting design principles and safety regulations. This determination ensures the safety of the removal process, improves removal efficiency, and enhances economic benefits.

[0069] According to an embodiment of the present disclosure, the coal bench 4 is divided into the primary coal bench mining area 41 and the secondary coal bench mining area 42 according to a sequence of coal exposure of the coal bench 4.

[0070] In summary, in the method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting according to the embodiment of the present disclosure, the bridge body removal area is divided into the primary bridge body removal area and the secondary bridge body removal area. The coal bench is divided into the primary coal bench mining area and the secondary coal bench mining area. First, the primary bridge body removal area is removed, then the primary coal bench mining area is mined, then the secondary bridge body removal area is removed, and finally the secondary coal bench mining area is mined. The method breaks and casts the material in the bridge body removal area by cast blasting, thereby dispersing the material in the bridge body removal area. On the one hand, the material of the intermediate bridge and the material at the goaf are stripped simultaneously, shortening the bridge removal time and advancing the bridge cut-through. On the other hand, the vast space of the goaf is fully utilized in conjunction with the storage of the secondary stripping material, reducing the secondary stripping workload in the bridge body removal area and saving the secondary stripping cost.

[0071] It should be noted that logic and / or steps shown in the flowcharts or described herein in other manners, for example, may be considered as a program list of executable instructions that are used to implement logical functions, and may be specifically implemented on any computer-readable medium, for an instruction execution system, apparatus, or device (for example, a computer-based system, a system including a processor, or another system that can fetch instructions from the instruction execution system, apparatus, or device and execute the instructions) to use, or for a combination of the instruction execution system, apparatus, or device to use. In terms of this specification, the "computer-readable medium" may be any apparatus that may include, store, communicate, propagate, or transmit programs, for the instruction execution system, apparatus, or device to use, or for a combination of the instruction execution system, apparatus, or device to use. More specific examples (this list is not exhaustive) of the computer-readable medium include the following: an electrical connection portion (an electrical apparatus) with one or more buses, a portable computer cartridge (an magnetic apparatus), a RAM, a ROM, an electrically erasable programmable read-only memory (EPROM 2025279835   15 Dec 2025 or flash memory), an optical fiber apparatus, and a compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be a piece of paper on which the program can be printed or another appropriate medium, because, for example, optical scanning may be performed on the paper or the another medium, then processing, such as edition, decoding, or another appropriate means when necessary, may be performed to obtain the program in an electronic manner, and then the program is stored in a computer storage.

[0072] It should be understood that the present disclosure may be implemented by using hardware, software, firmware, or a combination thereof. In the above implementations, a plurality of steps or methods may be implemented by using software or firmware that is stored in a memory and that is executed by a proper instruction execution system. For example, if implemented by using hardware, as in another implementation, this implementation may be implemented by any one or a combination of the following technologies known in the art: a discrete logic circuit with a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit with a suitable combinational logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), and the like.

[0073] In this specification, descriptions of reference terms such as "one embodiment", "some embodiments", "an example", "a specific example", and "some examples" indicate that specific features, structures, materials, or characteristics described in combination with the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] In addition, the terms "first" and "second" are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by "first" or "second" may explicitly or implicitly include at least one such feature. In the descriptions of the present disclosure, "a plurality of" means at least two, for example, two or three, unless otherwise specifically limited.

[0075] In the present disclosure, unless otherwise clearly limited, the terms ''installation'', "interconnection", ''connection'' and "fixation" etc. are intended to be understood in a broad sense. For example, the "connection" may be a fixed connection, a removable connection or an integral connection; may be a mechanical connection or an electrical connection; may be a direct connection or an indirect connection using a medium; and may be a communication or an interaction between two elements, unless otherwise clearly specified and limited. Those of 2025279835   15 Dec 2025 ordinary skill in the art may understand specific meanings of the above terms in the present disclosure based on a specific situation.

[0076] Although the embodiments of the present disclosure have been illustrated and described above, it will be appreciated that the above embodiments are illustrative and should not be construed as limiting the present disclosure. Changes, modifications, substitutions, and variations can be made to the above embodiments by a person of ordinary skill in the art within the scope of the present disclosure.

Claims

2025279835   15 Dec 20251. A method for rapid removal of an intermediate bridge and recovery of coal in a coal bench based on cast blasting, wherein the intermediate bridge comprises an intermediate bridge reserved area and a bridge body removal area; one side of the intermediate bridge reserved area is connected to an internal dump, and one side of the bridge body removal area is connected to the coal bench; the bridge body removal area is divided into a primary bridge body removal area and a secondary bridge body removal area; the coal bench is located beneath the bridge body removal area; the coal bench refers to coal formed beneath a bridge body, and the coal bench is divided into a primary coal bench mining area and a secondary coal bench mining area; and the method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench comprises:breaking and casting, by the cast blasting, a material in the primary bridge body removal area, and handling a remaining blast pile and a material requiring separate handling in the primary bridge body removal area after the cast blasting;mining the primary coal bench mining area to extract coal in the primary coal bench mining area;breaking and casting, by the cast blasting, a material in the secondary bridge body removal area, and handling a remaining blast pile and a material requiring separate handling in the secondary bridge body removal area after the cast blasting; andmining the secondary coal bench mining area to extract coal in the secondary coal bench mining area.

2. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, comprising: handling, by a single-bucket - truck process, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting, and the remaining blast pile and the material requiring separate handling in the secondary bridge body removal area after the cast blasting.

3. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 2, wherein the handling, by the single-bucket - truck process, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting, and the remaining blast pile and the material requiring separate handling in the secondary bridge body removal area after the cast blasting comprises: transporting, by single-bucket excavator loading and truck haulage, the remaining blast pile and the material requiring separate handling in the primary bridge body removal area after the cast blasting, and the remaining blast pile and the material requiring2025279835   15 Dec 2025separate handling in the secondary bridge body removal area after the cast blasting to the internal dump for dumping.

4. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein an effectively cast material in the primary bridge body removal area after the cast blasting and an effectively cast material in the secondary bridge body removal area after the cast blasting are temporarily stored in a goaf.

5. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein a boundary between the intermediate bridge reserved area and the bridge body removal area is determined according to a natural repose angle of a material of the intermediate bridge during secondary stripping.

6. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein during hole drilling and installation of an explosive charge for the cast blasting, an inclination angle of a blast hole for the cast blasting follows a principle of consistency with a bench slope angle and a principle of minimum burden.

7. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein during the cast blasting, a material casting direction is a direction toward the goaf at two sides of the intermediate bridge.

8. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein a boundary between the primary bridge body removal area and the secondary bridge body removal area is determined according to a natural repose angle of a material in the bridge body removal area.

9. The method for the rapid removal of the intermediate bridge and the recovery of the coal in the coal bench based on the cast blasting according to claim 1, wherein the coal bench is divided into the primary coal bench mining area and the secondary coal bench mining area according to a sequence of coal exposure of the coal bench.

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