A method of coal seam mining

Abstract

The present application relates to the technical field of mining, and provides a coal seam mining method, which comprises the following steps: arranging an upper layer roadway along a coal seam roof, arranging a lower layer roadway along a coal seam floor, and arranging at least two groups of operation units between the upper layer roadway and the lower layer roadway; each group of operation units comprises at least two branch roadways, each branch roadway is divided into an upper layer area corresponding to the upper layer roadway and a lower layer area corresponding to the lower layer roadway in the height direction; the branch roadways in each operation unit are sequentially mined and backfilled, the mining and backfilling of the corresponding upper layer area and lower layer area are completed, and the mining and backfilling of all the branch roadways in each operation unit are completed. The coal seam mining method provided by the present application realizes the alternate or successive operation between different operation units. After the branch roadways in one operation unit are backfilled, the adjacent operation unit can immediately start mining, the waiting and migration time of the equipment is reduced, and the continuity and efficiency of the overall mining work are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of mining technology, and more particularly to a method for mining coal seams. Background Technology

[0002] In the field of coal seam mining, traditional methods such as room-and-pillar mining or single-roadway layout systems are often used. These methods typically involve arranging roadways along a single facet of the coal seam and mining in an advancing or retreating sequence.

[0003] However, this mining method is prone to localized collapses or stress concentrations, threatening operational safety. Furthermore, traditional methods often require the creation of numerous coal pillars to support the roof, resulting in resource waste and high subsequent roadway maintenance costs. For thick or structurally complex coal seams, existing methods struggle to achieve effective, coordinated layered and segmented mining, impacting overall mining progress and economic efficiency. Summary of the Invention

[0004] This invention provides a coal seam mining method that solves the problems of low safety and inability to effectively mine coal seams in layers and sections.

[0005] This invention provides a coal seam mining method, comprising: An upper roadway is arranged along the top of the coal seam, and a lower roadway is arranged along the bottom of the coal seam. At least two sets of working units are arranged between the upper roadway and the lower roadway. Each set of working units includes at least two branch roadways. Each branch roadway is divided in the vertical direction into an upper area corresponding to the upper roadway and a lower area corresponding to the lower roadway. The branch tunnels in each of the work units are mined and backfilled sequentially to complete the mining and backfilling of the corresponding upper and lower areas, until all the branch tunnels in each work unit have been mined and backfilled.

[0006] According to an embodiment of the coal seam mining method provided by the present invention, the steps of mining and backfilling corresponding to the upper and lower seam regions specifically include: Mining is carried out by deploying equipment in the upper area. After the upper area is mined out and the equipment is withdrawn, mining is carried out in the corresponding lower area. After the lower layer area is mined out and the equipment is removed, the upper and lower layers are backfilled in a concentrated manner.

[0007] According to an embodiment of the coal seam mining method provided by the present invention, the mining and backfilling processes of each of the work units are sequentially staggered. At the same time, the different groups of work units are independently in different process stages corresponding to the upper layer mining, the lower layer opposite mining, and the centralized backfilling.

[0008] According to an embodiment of the coal seam mining method provided by the present invention, the total height of the branch roadway in the vertical direction is greater than the sum of the heights of the upper roadway and the lower roadway, forming an intermediate region between the upper region and the lower region.

[0009] According to an embodiment of the coal seam mining method provided by the present invention, when the thickness of the intermediate region is less than a preset thickness, the steps of completing the mining and backfilling of the corresponding upper and lower regions specifically include: When equipment is deployed in the upper region for mining, the middle region is mined simultaneously, and the upper region and the middle region are mined out at one time. Alternatively, while mining in the lower region, the middle region can be mined simultaneously, extracting both the lower region and the middle region at once. After the mining of the area containing the intermediate zone is completed and the equipment is removed, the upper, intermediate, and lower zones will be backfilled in a concentrated manner.

[0010] According to an embodiment of the coal seam mining method provided by the present invention, when the thickness of the intermediate region is greater than or equal to a preset thickness, the step of completing the mining and backfilling of the corresponding upper and lower regions specifically includes: Mining is carried out by deploying equipment in the upper area. After the upper area is mined out and the equipment is withdrawn, mining is carried out in the corresponding lower area. When mining the upper and lower regions, at least a portion of the intermediate region shall be preserved; After the lower layer area is mined out and the equipment is removed, the upper layer area, the middle layer area and the lower layer area are backfilled in a concentrated manner.

[0011] According to an embodiment of the coal seam mining method provided by the present invention, during the mining of the branch roadway, fresh air enters the mining face through the lower roadway, and return air is discharged through the upper roadway.

[0012] According to an embodiment of the coal seam mining method provided by the present invention, the specific steps of concentrated backfilling of the upper and lower layers include: Construct a sealed retaining wall at the end of the branch roadway to be backfilled that connects to the upper and lower roadways; Filling material is delivered to the upper and / or lower areas of the branch roadway through filling pipelines laid in the upper roadway.

[0013] According to an embodiment of the coal seam mining method provided by the present invention, the filling material used is one or more of coal gangue, fly ash, and cementitious material.

[0014] According to an embodiment of the coal seam mining method provided by the present invention, each of the said working units is arranged in parallel in sequence, and the branch roadways in each of the said working units are arranged in parallel in sequence.

[0015] The coal seam mining method provided by this invention, by setting up at least two sets of working units and sequentially mining and backfilling the branch roadways within each working unit, achieves alternating or continuous operations between different working units. Once the branch roadway in one working unit is backfilled, the adjacent working unit can immediately commence mining, reducing equipment waiting and relocation time and significantly improving the continuity and efficiency of the overall mining operation. Simultaneously, the layered, grouped, and sequential backfilling mining sequence ensures timely treatment of the goaf. Backfilling the mined portion provides active support for the roof and surrounding rock, effectively controlling stope pressure, suppressing large-scale roof collapse, and reducing the risk of roadway deformation, thereby greatly improving the safety of the underground working environment and the long-term stability of the roadway. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is one of the flowcharts of a coal seam mining method provided in an embodiment of the present invention.

[0018] Figure 2 This is a front view of a coal seam provided in an embodiment of the present invention.

[0019] Figure 3 This is a top view of a coal seam provided in an embodiment of the present invention.

[0020] Figure 4 This is a second schematic flowchart of a coal seam mining method provided in an embodiment of the present invention.

[0021] Figure 5 This is a front view of a coal seam provided in another embodiment of the present invention.

[0022] Figure 6 This is the third schematic flowchart of a coal seam mining method provided in an embodiment of the present invention.

[0023] Figure label: 10. Upper roadway; 20. Lower roadway; 30. Work unit; 310. Branch roadway; 3110. Upper area; 3120. Lower area; 3130. Intermediate area. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a coal seam mining method, primarily targeting coal seams with a thickness of 10 meters or more, such as... Figure 1 As shown, the method includes the following steps: Step S110: Arrange upper roadways along the top of the coal seam and lower roadways along the bottom of the coal seam. Arrange at least two sets of working units between the upper and lower roadways. Each set of working units includes at least two branch roadways. Each branch roadway is divided in the vertical direction into an upper area corresponding to the upper roadway and a lower area corresponding to the lower roadway.

[0026] Specifically, firstly, such as Figure 2 and Figure 3 As shown, one or more upper roadways 10 are arranged below the roof strata of the coal seam along the predetermined mining direction. The upper roadways 10 serve as the main upper passages for personnel, equipment, material transportation, and ventilation. Simultaneously, a corresponding lower roadway 20 is arranged near the floor of the coal seam, serving as the main lower passage and also used for coal transportation, drainage, and auxiliary ventilation. The upper roadways 10 and lower roadways 20 are spaced apart along their length and staggered in height.

[0027] Within the main coal seam area between the upper roadway 10 and the lower roadway 20, at least two sets of working units 30 are arranged. These working units 30 are arranged sequentially along the strike or dip of the coal seam. Each set of working units 30 is a relatively independent zone, comprising at least two branch roadways 310. These branch roadways 310 are vertically divided into two parts: the upper zone 3110 is directly connected to or adjacent to the upper roadway 10, and the lower zone 3120 is directly connected to or adjacent to the lower roadway 20. Each branch roadway 310 constitutes a small working face for coal seam mining.

[0028] Step S120: Sequentially mine and backfill the branch tunnels in each work unit, and complete the mining and backfilling of the corresponding upper and lower areas until all branch tunnels in each work unit have been mined and backfilled.

[0029] In this embodiment, each group of work units 30 can be mined and backfilled simultaneously, while the branch roadways 310 within each group of work units 30 can be started and backfilled sequentially, such as... Figure 2 and Figure 3 As shown, there are two sets of work units 30, namely the first work unit and the second work unit. The mining and backfilling work of these two units can be carried out simultaneously. For example, when the first work unit is backfilling the lower area 3120 of its first branch roadway 310, the second work unit can simultaneously carry out mining operations in the upper area 3110 of its first branch roadway 310, or carry out other operations. This parallel operation mode allows different processes such as tunneling, mining, and backfilling to be carried out in different spaces, maximizing the utilization of equipment and personnel, forming a continuous production cycle, and avoiding the interruption and waiting of processes common in traditional methods.

[0030] Although the work units 30 can be operated synchronously, the branch roadways 310 within each work unit 30 must be mined and backfilled in a strictly sequential manner to ensure safety and stability. Taking the first work unit as an example, it contains the first branch roadway 310 and the second branch roadway 310.

[0031] First, the first branch roadway 310 is mined or backfilled. After all operations in this roadway are completed, the adjacent second branch roadway 310 is treated in the same way. That is, the entire mining and backfilling cycle of a roadway must be completed before mining of adjacent branch roadways 310 within the same unit can begin. This sequence avoids stress superposition and surrounding rock instability caused by simultaneously disturbing multiple adjacent branch roadways 310, and provides stable lateral coal or backfill support for the safe operation of each branch roadway 310.

[0032] For any branch roadway 310 within work unit 30, mining can be carried out in two stages vertically: an upper region 3110 and a lower region 3120. The coal body in the upper region 3110 of the branch roadway 310 is mined first. After this part of the coal body is mined, the coal body in the lower region 3120 of the branch roadway 310 is then mined. After the lower region 3120 coal body is mined, backfilling can be carried out. At this point, all the coal in a single mining roadway has been extracted, and its space has been completely replaced by backfill material, forming a stable support structure.

[0033] The coal seam mining method provided by this invention, by setting up at least two sets of working units 30 and sequentially mining and backfilling the branch roadways 310 within each working unit 30, achieves alternating or continuous operations between different working units 30. Once the backfilling of a branch roadway 310 in one working unit 30 is completed, the adjacent working unit 30 can immediately commence mining, reducing equipment waiting and relocation time and significantly improving the continuity and efficiency of the overall mining operation. Simultaneously, the layered, grouped, and sequential backfilling mining sequence ensures timely treatment of the goaf. Backfilling the mined portion provides active support for the roof and surrounding rock, effectively controlling stope pressure, suppressing large-scale roof collapse, and reducing the risk of roadway deformation, thereby greatly improving the safety of the underground working environment and the long-term stability of the roadway.

[0034] In some embodiments, such as Figure 4 As shown, the specific steps for mining and backfilling corresponding to the upper region 3110 and the lower region 3120 include: Step S410: Deploy equipment in the upper area for mining. After the upper area is mined out and the equipment is withdrawn, carry out mining in the corresponding lower area.

[0035] Step S420: After the lower layer area is mined out and the equipment is removed, the upper and lower layers are backfilled in a concentrated manner.

[0036] Specifically, firstly, fully mechanized mining equipment (such as coal mining machines, hydraulic supports, scraper conveyors, etc.) is deployed in the upper layer area 3110 of branch roadway 310 to carry out coal mining operations. This stage focuses on mining the coal body located in the upper layer area 3110 of branch roadway 310. During mining operations, ventilation, personnel passage, and equipment and material transportation are carried out through the upper roadway 10. After the coal body in the upper layer area 3110 is completely mined out, forming a stable temporary space, all mining equipment is systematically withdrawn from the area.

[0037] Subsequently, mining is carried out in the corresponding lower area 3120. At this time, the workers and equipment mainly enter through the lower roadway 20. The mining direction of the lower area 3120 is opposite to that of the upper area 3110, allowing for the complete mining of the remaining coal body and facilitating the direct transport of the mined coal through the transportation system set up in the lower roadway 20. This phased and segmented mining method divides the coal body of a single branch roadway 310 into two relatively low mining heights for mining, significantly reducing the roof span and area exposed in a single mining operation, which is beneficial for roof control and adaptable to the operating height range of different equipment.

[0038] After the mining operations in the lower area 3120 are completed and all equipment is completely withdrawn from the upper and lower areas 3120 of the branch roadway 310, the connected goaf area formed by the entire branch roadway 310, including the mined upper area 3110 and the lower area 3120, will be backfilled in one go.

[0039] Backfilling operations are typically carried out directly through the upper roadway 10 or by installing backfill pipelines. High-performance backfill materials are used, injected from the top of the goaf by pumping or gravity flow, ensuring that the backfill fills the entire goaf space from bottom to top. Compared to staged backfilling, centralized backfilling simplifies the process and allows for more concentrated pipeline layout, ensuring the integrity and continuity of the backfill and forming a uniformly strong support structure. This backfill can promptly and proactively support the roadway roof and surrounding rock on both sides, effectively controlling the appearance of stope pressure, suppressing roof subsidence and collapse, and providing a stable lateral support boundary for adjacent subsequent branch roadways 310, ensuring the safety of subsequent operations.

[0040] It should be noted that the mining and backfilling processes of each work unit 30 are staggered and distributed sequentially; at the same time, different groups of work units 30 are independently in different process stages corresponding to the mining of the upper area 3110, the mining of the lower area 3120, and the concentrated backfilling.

[0041] like Figure 2 and Figure 3 As shown, there are two working units 30, namely the first working unit and the second working unit. Both the first working unit and the second working unit include the first branch roadway 310 and the second branch roadway 310.

[0042] In an initial time period, the first work unit may begin mining the upper layer 3110 of its first branch roadway 310. Simultaneously, the second work unit begins mining the lower layer 3120 of its first branch roadway 310 in the opposite direction (assuming its upper layer 3110 has been fully mined). Upon entering the next time period, after completing the upper layer mining of its first branch roadway 310, the first work unit transitions to mining the lower layer 3120 of that branch roadway in the opposite direction. After completing the lower layer mining of its first branch roadway 310, the second work unit withdraws its equipment and performs centralized backfilling of the roadway. Simultaneously, the second work unit can begin preparations or operations for mining the upper layer 3110 of its second branch roadway 310. This process continues in this manner; when the first work unit completes backfilling of its first branch roadway 310 and begins operations on its second branch roadway 310, the second work unit may already be handling the lower layer mining or backfilling work of its second branch roadway 310.

[0043] In this way, equipment such as coal mining machines and backfilling pump stations can be put into use or prepared for continuous operation in different work units (30), reducing equipment downtime. Personnel can also form professional teams to work in different units in rotation, forming a continuous production cycle. Moreover, the two main tasks of coal production and backfilling are carried out in parallel in different spaces, ensuring the continuity of coal output and the timeliness of goaf treatment. The overall production efficiency is significantly higher than the mode of sequential operation of work units (30).

[0044] In some embodiments, such as Figure 5 As shown, the total height of the branch tunnel 310 in the vertical direction is greater than the sum of the heights of the upper tunnel 10 and the lower tunnel 20, thus forming an intermediate region 3130 between the upper region 3110 and the lower region 3120. That is, within the branch tunnel 310, the portion located below the upper region 3110 and above the lower region 3120 forms an intermediate region 3130 that does not belong to either the upper region 3110 or the lower region 3120.

[0045] In this embodiment, when the thickness of the intermediate region 3130 is less than a preset thickness, for example, less than 2m, mining it alone would be inefficient and complex. Therefore, it can be incorporated into the adjacent upper or lower region 3120 and mined in one go. The steps for completing the mining and backfilling of the corresponding upper region 3110 and lower region 3120 specifically include: Step S510: When mining is carried out in the upper layer area, the middle layer area is mined simultaneously, and the upper layer area and the middle layer area are extracted in one operation. Alternatively, when mining is carried out in opposite directions in the lower layer area, the middle layer area is mined simultaneously, and the lower layer area and the middle layer area are extracted in one operation.

[0046] Step S520: After the area containing the intermediate zone has been mined and the equipment has been removed, the upper, intermediate, and lower zones are backfilled in a concentrated manner.

[0047] Specifically, when fully mechanized mining equipment is deployed in the upper zone 3110, the thin coal seam in the middle is simultaneously mined downwards. That is, the mining height of the equipment is adjusted to extract the upper zone 3110 and the entire middle zone 3130 coal body below it in one go, forming a unified mining space.

[0048] Alternatively, while mining is being carried out in the lower region 3120, the thin coal seam in the middle can be mined upwards simultaneously. That is, the coal seam in the middle region 3130 and its lower region 3120 can be mined out in one go from the lower region 3120 upwards.

[0049] Regardless of which merging scheme is adopted, it can avoid setting up a separate mining process for the thin intermediate area 3130, thereby simplifying the process and improving the efficiency of a single mining operation.

[0050] After the entire area, including the intermediate zone 3130, has been mined out and all equipment has been removed, a one-time centralized backfilling will be carried out on the large goaf area formed by the connection of the entire branch roadway 310. The backfill will fill the entire space and provide uniform support.

[0051] In this embodiment, when the thickness of the intermediate region 3130 is greater than or equal to a preset thickness, such as greater than or equal to 2m, the intermediate region 3130 is relatively thick and has the conditions to form an independent layer. If it is mined together with the upper and lower layers, it may lead to excessive mining height in one operation, causing problems such as difficulty in controlling the roof. Therefore, a strategy of retaining part of the intermediate region 3130 as temporary support is required. The specific steps for completing the mining and backfilling of the corresponding upper region 3110 and lower region 3120 include: Step S530: Deploy equipment in the upper area for mining. After the upper area is mined out and the equipment is withdrawn, carry out mining in the corresponding lower area.

[0052] Step S540: When mining the upper and lower zones, retain at least part of the intermediate zone.

[0053] Step S550: After the lower layer area is mined out and the equipment is removed, the upper, middle and lower layers are backfilled in a concentrated manner.

[0054] Specifically, during the operation, the upper layer 3110 is mined first, and after the equipment is completely removed, the lower layer 3120 is mined in the opposite direction.

[0055] During the mining of the upper zone 3110 and the lower zone 3120, at least a portion of the intermediate zone 3130 coal body will be left unmined. This portion of the intermediate zone 3130 coal body will be temporarily retained in the middle of the goaf as an isolation pillar or intermediate pillar after the upper and lower zones 3120 are mined.

[0056] After the upper 3110 zone is mined, it acts as a cushion layer to support the exposed roof. During the mining of the lower 3120 zone, it also acts as a false roof to provide overhead cover for the lower 3120 operations. This effectively divides the large goaf into two controlled small spaces in time, significantly improving the surrounding rock stress state and roof stability during each stage of the operation, and providing a safer working environment for the equipment.

[0057] After the lower zone 3120 is mined out and all equipment is removed, the entire space, including the upper zone 3110, the reserved middle zone 3130 coal body, and the lower zone 3120, will be backfilled in a final, centralized manner.

[0058] It should be noted that during the mining of the branch roadway 310, for example, after both the upper area 3110 and the lower area 3120 have been mined, fresh air enters the working face through the lower roadway 20, and return air is discharged through the upper roadway 10. During mining operations at the working face, the fresh airflow first enters the lower area 3120 of the branch roadway 310 or the lower end of the working face under the guidance of local ventilation facilities, via the lower main passage, the lower roadway 20. Subsequently, under the action of ventilation dynamics, the fresh air flows upward through the most active coal face area and equipment concentration area, washing the working face, providing oxygen for the workers, and diluting and carrying away harmful gases and dust such as methane and coal dust generated during mining. After becoming polluted airflow, the return air continues to flow upward, merging into the upper area 3110 of the branch roadway 310, and finally being discharged to the mine's main return air system via the upper main passage, the upper roadway 10.

[0059] Specifically, during the mining of the upper zone 3110, fresh air enters from the lower roadway 20, rises to the working face of the upper zone 3110 via connecting roadways or reserved passages, and polluted air is directly discharged into the upper roadway 10. At this time, the lower zone 3120 serves as an air intake passage. During the mining of the lower zone 3120, fresh air enters the working face of this zone directly from the adjacent lower roadway 20, and polluted air rises through the mined space of the upper zone 3110 (or a reserved ventilation passage) and is introduced into the upper roadway 10. At this time, the filled or unfilled space of the upper zone 3110 acts as a return air passage.

[0060] In some embodiments, such as Figure 6 As shown, the specific steps for centralized backfilling of the upper region 3110 and the lower region 3120 include: Step S610: Construct a sealed retaining wall at the end of the branch tunnel to be backfilled that connects to the upper and lower tunnels.

[0061] Step S620: Convey filling material to the upper and / or lower areas of the branch roadway through filling pipelines laid in the upper roadway.

[0062] In this embodiment, a sealed retaining wall can be constructed at the interface between the branch roadway 310 to be backfilled and the main channels (upper roadway 10 and lower roadway 20) connected to its two ends. The main function of the retaining wall is to seal the space to be filled, prevent the filling material from leaking into the main roadway under pressure, and ensure that the filling material solidifies within the predetermined area; at the same time, it also serves as an isolation function to ensure that operations in other areas are not disturbed.

[0063] Retaining walls are typically constructed using high-strength concrete masonry, or a combination of air-bag-type rapid sealing devices and concrete pouring. The wall must possess sufficient compressive strength to withstand the pressure from the filling pump and subsequent surrounding rock pressure. Observation holes, drainage filters, and through-wall sleeves for filling pipelines are pre-embedded in the retaining wall. The drainage filters are used to remove air and excess moisture from the goaf during filling, promoting the compaction of the filling material.

[0064] After the sealed retaining wall is constructed, filling material is transported to the goaf of branch roadway 310 through filling pipelines pre-laid in the upper roadway 10. The filling material used is one or a combination of coal gangue, fly ash, and cementitious material.

[0065] Coal gangue serves as the primary filling medium. It is typically sourced from mine shaft discharge or coal washing plants, crushed and screened to a suitable particle size (e.g., less than 30mm). Its functions are twofold: first, to act as the skeleton of the filling body, providing volume and mechanical stability; and second, to enable the on-site resource utilization of mine solid waste underground, reducing land occupation and environmental pollution caused by surface accumulation. Fly ash, usually derived from industrial waste from power plants, is a fine-grained active admixture that primarily fills the tiny voids between coal gangue particles, making the filling body more compact. The binder is typically cement (such as ordinary Portland cement) or a special cementing material developed specifically for mine filling. The binder undergoes a hydration reaction to bind the loose coal gangue and fly ash into a cohesive whole, forming a structural filling body with designed load-bearing capacity. The amount used can be adjusted according to the required strength.

[0066] In some embodiments, such as Figure 2 , Figure 3 and Figure 5 As shown, each work unit 30 is arranged in parallel in sequence, and the branch roadways 310 in each work unit 30 are arranged in parallel in sequence.

[0067] Specifically, each working unit 30 is arranged in parallel within the coal seam plane. Within each working unit 30, at least two branch roadways 310 constituting that unit are also arranged in a parallel manner, thus forming multiple parallel, regular strip-shaped mining areas within the unit. This parallel arrangement makes the stress distribution around the stope relatively regular and predictable, which is beneficial for long-term mine pressure monitoring and effective support, thereby improving the stability of coal seam mining.

[0068] Understandably, depending on the specific coal seam geological conditions, mining boundary shape, existing roadway system, or special mining safety requirements, each working unit 30 and its internal branch roadways 310 can also adopt other adaptive arrangements. For example, with a central transport point, each working unit 30 and its branch roadways 310 can extend radially outwards, suitable for situations where the center of the mining block has specific geological structures. They can also be staggered, with the working units 30 or branch roadways 310 intersecting at a certain angle. This arrangement may help optimize roof pressure transmission in a specific direction or adapt to irregular coal seam boundaries.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for mining coal seams, characterized in that, include: An upper roadway is arranged along the top of the coal seam, and a lower roadway is arranged along the bottom of the coal seam. At least two sets of working units are arranged between the upper roadway and the lower roadway. Each set of working units includes at least two branch roadways. Each branch roadway is divided in the vertical direction into an upper area corresponding to the upper roadway and a lower area corresponding to the lower roadway. The branch tunnels in each of the work units are mined and backfilled sequentially to complete the mining and backfilling of the corresponding upper and lower areas, until all the branch tunnels in each work unit have been mined and backfilled.

2. The coal seam mining method according to claim 1, characterized in that, The specific steps for mining and backfilling corresponding to the upper and lower regions include: Mining is carried out by deploying equipment in the upper area. After the upper area is mined out and the equipment is withdrawn, mining is carried out in the corresponding lower area. After the lower layer area is mined out and the equipment is removed, the upper and lower layers are backfilled in a concentrated manner.

3. The coal seam mining method according to claim 2, characterized in that, The mining and backfilling processes in each of the aforementioned work units are staggered and distributed sequentially. At the same time, the different groups of work units are independently in different process stages corresponding to the upper layer mining, the lower layer opposite mining, and the centralized backfilling.

4. The coal seam mining method according to claim 3, characterized in that, The total height of the branch tunnels in the vertical direction is greater than the sum of the heights of the upper tunnels and the lower tunnels, forming an intermediate region between the upper region and the lower region.

5. The coal seam mining method according to claim 4, characterized in that, When the thickness of the intermediate region is less than the preset thickness, the steps for completing the mining and backfilling of the corresponding upper and lower regions specifically include: When equipment is deployed in the upper region for mining, the middle region is mined simultaneously, and the upper region and the middle region are mined out at one time. Alternatively, while mining in the lower region, the middle region can be mined simultaneously, extracting both the lower region and the middle region at once. After the mining of the area containing the intermediate zone is completed and the equipment is removed, the upper, intermediate, and lower zones will be backfilled in a concentrated manner.

6. The coal seam mining method according to claim 4, characterized in that, When the thickness of the intermediate region is greater than or equal to a preset thickness, the steps for completing the mining and backfilling of the corresponding upper and lower regions specifically include: Mining is carried out by deploying equipment in the upper area. After the upper area is mined out and the equipment is withdrawn, mining is carried out in the corresponding lower area. When mining the upper and lower regions, at least a portion of the intermediate region shall be preserved; After the lower layer area is mined out and the equipment is removed, the upper layer area, the middle layer area and the lower layer area are backfilled in a concentrated manner.

7. The coal seam mining method according to claim 1, characterized in that, During the mining of the branch roadway, fresh air enters the mining face through the lower roadway, and return air is discharged through the upper roadway.

8. The coal seam mining method according to any one of claims 2-7, characterized in that, The specific steps for the centralized backfilling of the upper and lower regions include: Construct a sealed retaining wall at the end of the branch roadway to be backfilled that connects to the upper and lower roadways; Filling material is delivered to the upper and / or lower areas of the branch roadway through filling pipelines laid in the upper roadway.

9. The coal seam mining method according to claim 8, characterized in that, The filling material used is one or a combination of coal gangue, fly ash, and cementitious materials.

10. The coal seam mining method according to any one of claims 1-7, characterized in that, The work units are arranged in parallel in sequence, and the branch tunnels in each work unit are arranged in parallel in sequence.

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