A thick coal seam high recovery rate, high roof rate lane type strip filling mining method

Abstract

This invention provides a high-recovery, high-roof-reaching method for strip backfilling mining of thick coal seams, belonging to the technical field of mining methods. This method addresses the remaining issues of triangular coal seams in lower layers from the perspective of backfilling mining technology, thereby increasing the recovery rate to over 98%. It also addresses the low efficiency of current strip backfilling mining in cutting and transferring coal by selecting suitable chain-cutting roadheaders, continuous miners, and subsequent continuous transport and transfer equipment, thus improving backfilling mining efficiency. Furthermore, it improves the branch roadway excavation process by adding a process to create a false roof dip angle at the roadway entrance, increasing the branch roadway length while meeting the requirements of backfilling and roof reach, thereby reducing the frequency of turning and retreating of mining equipment and improving the working face production efficiency. This method has positive significance for improving the level of underground mining technology, increasing coal resource recovery rate, and improving mining efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of mining methods, and specifically discloses a roadway strip filling mining method for thick coal seams with high recovery rate and high roof contact rate. Background Technology

[0002] With the rapid development of the coal industry, the technology and equipment for backfilling mining under coal seams have been significantly improved. In particular, the roadway-type strip backfilling technology, due to its significant advantages such as good surface subsidence control and high resource recovery rate, has been widely used in domestic coal enterprises. However, when roadway-type strip backfilling technology is applied to coal seams with a thickness of 6m to 8m, the following three problems arise:

[0003] 1. After the upper layer is mined in the branch roadway, when the lower layer is pulled back for mining, due to the reasons of the supporting transportation and the tunneling machine itself, in order to facilitate coal transportation and the tunneling machine's withdrawal, some triangular coal will inevitably be left in the area of ​​about 20m at the roadway entrance, thus forming coal residue with a certain slope. Ultimately, this part of the residual triangular coal cannot be mined, resulting in resource waste and a relatively low recovery rate, which cannot meet the requirements of sustainable development of coal mining enterprises.

[0004] 2. Currently, the general method for roadway strip mining is to use a tunneling machine to cut coal, a single drilling rig for support, and a shuttle car or loader to remove coal. The efficiency of the tunneling machine in cutting coal is not high, and the efficiency of using a single drilling rig for support is also low. The intermittent coal removal and transportation capacity of the shuttle car or loader is also small. Therefore, the overall mining efficiency is low.

[0005] 3. In order to ensure that the roadway can fully connect with the roof during backfilling construction, the length of the branch roadway is generally controlled below 100m in the design of the roadway strip backfilling mining. If the branch roadway is too short, the mining equipment will frequently turn and retreat during the mining process, which will greatly reduce the backfilling mining efficiency. Summary of the Invention

[0006] This invention provides a method for high recovery rate and high roof contact rate tunneling strip backfilling mining of thick coal seams, solving the above-mentioned technical problems.

[0007] The above-mentioned method for high-recovery and high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method includes the following steps:

[0008] S1, a longwall mining face with full air pressure ventilation is arranged. The intake airway of the longwall mining face is arranged along the roof of the coal seam, the return airway is arranged along the floor of the coal seam, and the connecting roadway is connected to the intake airway and the return airway of the working face, respectively.

[0009] S2, the working face intake airway is equipped with 1 chain cutter and anchor machine, 1 set of mobile telescopic transfer unit, 1 transfer crusher and belt conveyor;

[0010] The return airway of the working face is equipped with one continuous coal mining machine, one mobile telescopic transfer unit, one transfer crusher, and a belt conveyor.

[0011] S3, a chain cutterhead and anchor machine located in the intake airway of the working face, starts from the opening of the first branch roadway on the outermost side of the intake airway of the working face along the inclined direction and tunnels along the roof. The mobile telescopic transfer unit and the transfer crusher complete the transfer of coal after the chain cutterhead and anchor machine until the tunneling reaches the position that connects with the return airway of the working face, and the layered mining on the first branch roadway is completed. The chain cutterhead and anchor machine then exits the first branch roadway.

[0012] S4. When the chain-cutting roadheader retreats to the entrance of the working face airway, the chain-cutting roadheader is used to break through the roof of the roadway to form a pseudo-slope at the entrance.

[0013] S5, the chain-type roadheader is carrying out the excavation of the 3rd branch roadway. At the same time, the continuous coal mining machine arranged in the return airway of the working face is carrying out secondary bottom mining of the remaining layered coal seams of the 1st branch roadway along the inclined direction from the return airway of the working face, completing the mining of all coal seams in the 1st branch roadway. The mobile telescopic transfer unit and the transfer crusher complete the coal transfer work after the continuous coal mining machine.

[0014] S6, the continuous coal mining machine withdraws from the first branch roadway. After the third branch roadway is excavated and the pseudo-slope at the roadway entrance is completed, the second bottom pulling work of the third branch roadway is carried out to complete the mining of all coal seams in the third branch roadway. At the same time, the chain-type roadheader carries out the excavation operation of the fifth branch roadway.

[0015] S7, repeat step S6 until all coal seams in the 5th, 7th, 9th... branch roadways are mined;

[0016] S8. Start tunneling from the second branch roadway adjacent to the first branch roadway. Repeat steps S3-S7 to complete the mining of all coal seams in the second, fourth, sixth... branches roadways.

[0017] In the above-mentioned high recovery rate and high roof contact rate roadway strip backfilling mining method for thick coal seams, the chain cutter is the EBM300M-2A chain cutter.

[0018] The continuous coal mining machine is the EML340 continuous coal mining machine.

[0019] In the above-mentioned high recovery rate and high roof contact rate roadway strip filling mining method for thick coal seams, the length of the pseudo-slope at the roadway entrance is 5m and the dip angle is not less than 10°.

[0020] In the above-mentioned high recovery rate and high roof contact rate roadway strip filling mining method for thick coal seams, when the EBM300M-2A chain cutterhead and anchor machine is used for tunneling, the unsupported roof distance is determined according to the geological conditions of the coal seam. After the required unsupported roof distance is reached, the exposed roadway is supported.

[0021] In the above-mentioned high recovery rate and high roof contact rate roadway strip filling mining method for thick coal seams, the filling pipeline and the exhaust pipeline are both suspended at the highest point of the pseudo-slope at the roadway entrance.

[0022] In the above-mentioned high recovery rate and high roof contact rate roadway strip backfilling mining method for thick coal seams, the two sides of the branch roadway are not supported when the EML340 continuous coal mining machine is performing the secondary bottom pulling operation, and the backfilling operation is carried out immediately after the bottom pulling is completed.

[0023] In the above-mentioned high-recovery and high-roof-reaching roadway strip backfilling mining method for thick coal seams, the backfilling materials include coal gangue, fly ash, mineral powder, and additives. The maximum particle size of the coal gangue is required to be 30mm. The proportions are as follows: 45.2% coal gangue, 20.3% fly ash, 10.5% mineral powder, 23.9% water, 0.1% additives, and a slurry concentration of 76.1%.

[0024] In the above-mentioned high-recovery and high-roof-reach ratio roadway strip backfilling mining method for thick coal seams, the backfilling station includes a crushing and sand-making system, a forced mixing system, a backfilling pump, backfilling pipelines, and an exhaust pipeline. The crushing and sand-making system crushes coal gangue into finished gangue with a particle size of less than 30mm. The finished gangue is transported to the forced mixing system by a vertical hoist. Mineral powder and fly ash are transported to the forced mixing system by a screw conveyor. Water is pumped to the forced mixing system after being metered by a water pump. Finally, the water is mixed evenly by the forced mixing system and pumped to the branch roadway after mining through the pre-laid backfilling pipeline by the backfilling pump.

[0025] In the above-mentioned high-recovery and high-roof-reaching roadway strip backfilling mining method for thick coal seams, the width of the backfilling return airway and the backfilling intake airway is 6.5~8m; the height of the backfilling return airway and the backfilling intake airway is 4.5m; the angle between the branch roadway and the backfilling intake airway is 90°; the length of the branch roadway is 150~180m; the width of the branch roadway is 6.5~8m; the width of the coal pillar between the branch roadways is 6.5~8m; the thickness of the upper layer of the branch roadway is 4.5m; and the thickness of the lower layer of the branch roadway is 1.5~3.5m.

[0026] In the above-mentioned high recovery rate and high roof contact rate roadway strip filling mining method for thick coal seams, the EBM300M-2A chain cutterhead and anchor machine uses local ventilation fan for upper layer mining in the branch roadway; the EML340 continuous coal mining machine uses full air pressure ventilation for lower layer mining in the branch roadway.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The intake airway of the working face is arranged along the roof, and the return airway of the working face is arranged along the bottom of the coal seam. During mining, the EBM300M-2A chain cutterhead and anchor machine arranged in the intake airway of the working face advances along the inclined direction from the intake airway to the return airway of the working face. After the branch roadway is connected, the EML340 continuous coal mining machine arranged in the return airway of the working face advances along the inclined direction from the return airway to the intake airway of the working face to mine the lower layer. This mining method will not form triangular coal residues, and the coal resource recovery rate of the working face will reach more than 98%, which greatly improves the coal recovery rate.

[0029] 2. The EBM300M-2A chain cutterhead and EML340 continuous miner are used to mine longwall faces. Because the EBM300M-2A chain cutterhead and EML340 continuous miner blast heads adopt a horizontal axis design, the equipment has high power and therefore high coal cutting efficiency, which greatly improves the coal cutting efficiency.

[0030] 3. The EBM300M-2A chain cutterhead and anchor rig comes with two hydraulic drilling arms, which provides faster support speed and higher support efficiency compared to a single drilling rig.

[0031] 4. The mobile telescopic transfer unit is a continuous transport mode, which has a greater transport capacity compared to the intermittent transport modes such as traditional shuttle cars and loaders. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific 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 from these drawings without creative effort.

[0033] Figure 1 Schematic diagram of roadway and equipment layout for thick coal seam backfilling mining face;

[0034] Figure 2 for Figure 1 Cross-sectional view along the AA direction;

[0035] Figure 3 for Figure 1 Cross-sectional view along the BB direction;

[0036] Figure 4 for Figure 1 Cross-sectional view along the CC direction;

[0037] Figure 5 This is a front view of the pseudo-slope at the entrance of the back mining branch roadway;

[0038] Figure 6 for Figure 5 Side view.

[0039] In the diagram: 1—Working face intake airway, 2—Mobile telescopic transfer unit, 3—Transfer crusher, 4—Branch roadway, 5—Belt conveyor, 6—Backfilling pipeline, 7—Centralized intake airway, 8—Centralized return airway, 9—Backfilling body, 10—Working face return airway, 11—EML340 continuous coal mining machine, 12—EBH300M-2A chain cutterhead, 13—Connecting roadway, 14—Pseudo-slope at roadway entrance. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0041] This embodiment provides a high recovery rate and high roof contact rate roadway strip filling mining method for thick coal seams (thickness 6~8m), mainly involving eight aspects: roadway layout, mining equipment matching and layout, coal mining procedures, upper and lower layered mining technology of branch roadways, pseudo-dip angle treatment technology of roof at the roadway entrance of branch roadways, ventilation method, thick coal seam filling material ratio, and thick coal seam filling technology.

[0042] (1) Layout of alleyways

[0043] For the occurrence conditions of thick coal seams (thickness 6~8m), a longwall mining face with full air pressure ventilation is first arranged. The intake airway 1 of the longwall mining face is arranged along the roof of the coal seam, and the return airway 10 is arranged along the floor of the coal seam. The connecting roadway 13 (cut-out) is connected to the intake airway 1 and the return airway 10 of the longwall mining face respectively. During mining, a series of branch roadways 4 with a width of 6.5~8m and a length of 100~180m are excavated along the dip direction in the longwall mining face.

[0044] (2) Downhole equipment configuration and layout

[0045] The mining equipment includes: 1 EBM300M-2A chain cutterhead and anchorer, 1 EML340 continuous coal mining machine, 2 sets of mobile telescopic transfer units, 2 transfer crushers, and belt conveyors. The filling equipment includes: a crushing and sand making system, a forced twin-shaft mixing system, a coal mine-specific filling pump, and filling pipelines. In the working face intake airway 1, there is 1 EBM300M-2A chain cutterhead and anchorer, 1 set of mobile telescopic transfer units, 1 transfer crusher, and belt conveyors. In the working face return airway 10, there is 1 EML340 continuous coal mining machine, 1 set of mobile telescopic transfer units, 1 transfer crusher, and belt conveyors.

[0046] (3) Coal mining process:

[0047] The longwall mining face is mined in two stages using a roadway-style strip mining method. The branch roadway 4 is mined by a one-mining-one-leaving-one-leaving-one-skipping mining method. The overall mining method is forward mining, and each branch roadway 4 is mined by forward mining in both the upper and lower layers. The EBM300M-2A chain cutterhead 12 and EML340 continuous mining machine 11 are used to complete the coal cutting and loading work. The mobile telescopic transfer unit 2 and transfer crusher 3 are used to complete the coal transfer work after the EBM300M-2A chain cutterhead 12 and EML340 continuous mining machine 11. The transportation process is as follows: EBM300M-2A chain cutterhead 12 / EML340 continuous mining machine in the working face intake airway cuts, loads, and transports coal → Mobile telescopic transfer unit and transfer crusher in the working face intake airway / working face return airway continuously transport and transfer coal → Belt conveyor in the working face intake airway / Belt conveyor in the working face intake airway → Belt conveyor in the centralized transportation roadway → Belt conveyor in the main transportation roadway → Transported to the surface coal bunker.

[0048] The specific procedures are as follows:

[0049] a: An EBM300M-2A chain cutterhead and anchor machine 12, positioned in the intake airway 1 of the working face, begins its diagonal excavation from the opening of the outermost first branch roadway of intake airway 1 and advances along the roof. A mobile telescopic transfer unit 2 and a transfer crusher 3 follow behind the EBM300M-2A chain cutterhead and anchor machine 12 to complete the coal transfer. The first branch roadway has a width of 6.5~8m and a height of 4.5m. The unsupported roof distance is determined based on the coal seam geological conditions. After the required unsupported roof distance is reached, support construction is carried out on the exposed roadway.

[0050] b: Repeat step a until the tunneling reaches the position where it connects with the return airway 10 of the working face, and complete the layered mining of the first branch roadway. The EBM300M-2A chain cutter 12 exits the first branch roadway and skips mining to carry out the tunneling operation of the third branch roadway. The tunneling width of the third branch roadway is 6.5~8m and the tunneling height is 4.5m.

[0051] c: While the EBM300M-2A chain cutterhead and anchor machine 12 is excavating the third branch roadway, the EML340 continuous coal mining machine 11, located in the return airway 10 of the working face, performs secondary bottom-pulling mining of the remaining lower-layered coal seams in the first branch roadway along the inclined direction from the return airway 10, completing the mining of all coal seams in the first branch roadway. The mobile telescopic transfer unit 2 and the transfer crusher 3 complete the coal transfer work after the EML340 continuous coal mining machine 11. No support is required on the two sides during this bottom-pulling operation. To control the stability of the two sides, backfilling is carried out immediately after the bottom-pulling is completed.

[0052] d: After step c is completed, the EML340 continuous coal mining machine 11 is withdrawn. The bottoming work of the third branch roadway will be carried out after the third branch roadway is excavated and connected.

[0053] e: After step d is completed, repeat steps a, b, c, and d again to complete steps 5, 7, 9... The upper-layer excavation and lower-layer mining of the branch roadways are completed using an intermittent skip-mining method. The EBM300M-2A chain cutterhead 12 and the EML340 continuous miner 11 are followed by a mobile telescopic transfer unit 2 and a transfer crusher 3. This completes the first stage of all branch roadway mining operations.

[0054] f: While the EBM300M-2A chain cutterhead and anchor machine 12 and the EML340 continuous coal mining machine 11 are carrying out branch roadway excavation, the backfilling operation is carried out simultaneously with the branch roadway excavation, and the operation is carried out in parallel, always keeping no more than three roadways in each entire working face.

[0055] g: After steps e and f are completed, the second stage of mining work will commence, namely the mining of the coal pillars between the backfill bodies. Mining operations will begin from one side of the first branch roadway, eventually completing the upper-layer excavation and lower-layer mining of the second, fourth, sixth, and so on branch roadways. Steps a, b, c, d, and e will be repeated to complete the mining of the remaining branch roadways. Ultimately, a high recovery rate of over 98% will be achieved at the working face.

[0056] (4) Process for treating the pseudo-inclination angle of the roof at the entrance of the branch roadway

[0057] This process aims to improve the roof contact effect of the roadway by artificially creating a pseudo-inclination angle, thereby increasing the length of branch roadway 4. Increasing the length of branch roadway 4 reduces the frequency of turning and retreating of mining equipment, thus improving the production efficiency of the working face. Specifically, after the EBM300M-2A chain cutterhead 12 completes the upper coal mining of branch roadway 4 and before the EML340 continuous coal mining machine 11 mines the lower coal layers, when the EBM300M-2A chain cutterhead 12 retreats to the entrance of the intake roadway 1, it uses the EBM300M-2A chain cutterhead 12 to break through the roadway roof, ultimately forming a pseudo-slope 14 at the roadway entrance with a length of 5m, an inclination angle of not less than 10°, and a slope width of 3m. The filling pipeline 6 and exhaust pipeline are suspended at the highest point of the slope to ensure better roof contact of the filling slurry during the filling process.

[0058] (5) Ventilation

[0059] When the EBM300M-2A chain cutterhead and anchor machine 12 is used for upper layer mining of branch roadway 4, local ventilation is used; when the EML340 continuous coal mining machine 11 is used for lower layer mining of branch roadway 4, full air pressure ventilation is used.

[0060] (6) Filling scheme

[0061] a: Filling material proportions

[0062] The filling material mainly includes coal gangue, fly ash, mineral powder, and additives. The maximum particle size of coal gangue is required to be 30mm. The proportions are as follows: 45.2% coal gangue, 20.3% fly ash, 10.5% mineral powder, 23.9% water, 0.1% additives, and a slurry concentration of 76.1%.

[0063] b: Filling process

[0064] The filling station mainly includes a crushing and sand making system, a forced mixing system, a filling pump, and a pipeline system. The crushing and sand making system crushes the raw gangue into finished gangue with a particle size of less than 30mm. The finished gangue is transported to the forced mixing system by a vertical elevator. Mineral powder, fly ash, etc. are transported to the forced mixing system by a screw conveyor. Water is pumped to the forced mixing system after being metered. Finally, the mixture is evenly mixed by the forced mixing system and pumped to the branch roadway 4 after mining through the pre-laid filling pipeline 6 by the filling pump.

[0065] The specific construction process parameters are as follows.

[0066] Width of filling return airway and filling intake airway: 6.5~8m; Height of filling return airway and filling intake airway: 4.5m; Angle between branch roadway 4 and filling intake airway: 90°; Length of branch roadway 4: 150~180m; Width of branch roadway 4: 6.5~8m; Width of coal pillar between branch roadway 4: 6.5~8m; Thickness of upper layer of branch roadway 4: 4.5m; Thickness of lower layer of branch roadway 4: 1.5~3.5m; Pseudo-slope 14 at roadway entrance: inclination angle not less than 10°, width 3m, length 5m.

[0067] This method addresses the remaining issues in the lower-layer triangular coal seam from the perspective of backfilling mining technology, thereby improving the recovery rate to over 98%. It also addresses the low efficiency of current roadway-type strip mining in cutting and transferring coal by selecting suitable chain-cutting roadheaders, continuous coal mining machines, and subsequent continuous transport and transfer equipment, thus improving backfilling mining efficiency. Furthermore, it improves the branch roadway excavation process by adding a technique to create a false roof dip angle at the roadway entrance. This increases the length of the branch roadway while meeting the requirements of backfilling and roof connection, thereby reducing the frequency of turning and retraction of mining equipment and improving the working face's production efficiency. This method has positive significance for improving the technical level of underground mining, increasing coal resource recovery rate, and improving mining efficiency.

[0068] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method, characterized in that, Includes the following steps: S1, arrange a longwall mining face with full air pressure ventilation. The working face intake airway (1) of the longwall mining face is arranged along the top of the coal seam, the working face return airway (10) is arranged along the bottom of the coal seam, and the connecting airway (13) is connected to the working face intake airway (1) and the working face return airway (10) respectively. S2, the working face intake airway (1) is equipped with 1 chain-cutting anchor machine, 1 set of mobile telescopic transfer unit (2), 1 transfer crusher (3), and belt conveyor (5). The working face return airway (10) is equipped with one continuous coal mining machine, one set of mobile telescopic transfer unit (2), one transfer crusher (3), and belt conveyor (5); S3, a chain-type roadheader is set up in the intake airway (1) of the working face and starts from the opening of the first branch roadway on the outermost side of the intake airway (1) of the working face along the inclined direction and tunnels along the roof. The mobile telescopic transfer unit (2) and the transfer crusher (3) complete the transfer of coal after the chain-type roadheader until the tunneling reaches the position of the connection with the return airway (10) of the working face, and the layered mining on the first branch roadway is completed. The chain-type roadheader withdraws from the first branch roadway. S4, when the chain-cutting anchor machine retreats to the entrance of the working face air intake roadway (1), the chain-cutting anchor machine is used to break the roof of the roadway to form a pseudo slope (14) at the entrance of the roadway. S5, the chain-type roadheader performs the tunneling operation of the third branch roadway, and at the same time, the continuous coal mining machine arranged in the working face return airway (10) performs secondary bottom mining of the remaining lower layer coal seam of the first branch roadway from the working face return airway (10) along the inclined direction, and completes the mining of all coal seams in the first branch roadway. The mobile telescopic transfer unit (2) and the transfer crusher (3) complete the transfer of coal after the continuous coal mining machine. S6, the continuous coal mining machine exits the first branch roadway. After the third branch roadway is excavated and the pseudo-slope at the roadway entrance (14) is completed, the second bottom pulling work of the third branch roadway is carried out to complete the mining of all coal seams in the third branch roadway. At the same time, the chain-type roadheader carries out the excavation operation of the fifth branch roadway. S7, repeat step S6 until all coal seams in the 5th, 7th, 9th... branch roadways are mined; S8. Start tunneling from the second branch roadway adjacent to the first branch roadway. Repeat steps S3-S7 to complete the mining of all coal seams in the second, fourth, sixth... branches roadways.

2. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 1, characterized in that, The chain cutterhead is an EBM300M-2A chain cutterhead (12). The continuous coal mining machine is the EML340 continuous coal mining machine (11).

3. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 1, characterized in that, The pseudo-slope (14) at the alley entrance is 5m long and has an inclination angle of not less than 10°.

4. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 2, characterized in that, When the EBM300M-2A chain cutter and anchor machine (12) is performing tunneling operations, the unsupported roof distance is determined according to the geological conditions of the coal seam. After the tunneling reaches the required unsupported roof distance, the exposed tunnel is supported.

5. The method for high-recovery, high-roof-reaching roadway strip backfilling mining of thick coal seams according to claim 4, characterized in that, The filling pipeline (6) and the exhaust pipeline are both suspended at the highest point of the pseudo-slope (14) at the entrance of the tunnel.

6. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 5, characterized in that, When the EML340 continuous coal mining machine (11) is performing secondary bottom pulling work, the sidewalls of the branch roadway (4) are not supported. After the bottom pulling is completed, the filling operation is carried out immediately.

7. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 6, characterized in that, The filling material includes coal gangue, fly ash, mineral powder, and additives. The maximum particle size of the coal gangue is required to be 30mm. The proportions are as follows: 45.2% coal gangue, 20.3% fly ash, 10.5% mineral powder, 23.9% water, 0.1% additives, and a slurry concentration of 76.1%.

8. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 1, characterized in that, The filling station includes a crushing and sand making system, a forced mixing system, a filling pump, a filling pipeline (6), and an exhaust pipeline; The coal gangue is crushed into finished gangue with a particle size of less than 30mm using a crushing and sand making system. The finished gangue is transported to the forced mixing system by a vertical hoist. The mineral powder and fly ash are transported to the forced mixing system by a screw conveyor. Water is pumped to the forced mixing system after being metered by a water pump. Finally, the water is mixed evenly by the forced mixing system and pumped to the branch roadway (4) after mining by a filling pump through a pre-laid filling pipeline (6).

9. The method for high-recovery, high-roof-reaching roadway strip backfilling mining of thick coal seams according to claim 8, characterized in that, Width of filling return airway and filling intake airway: 6.5~8m; Height of filling return airway and intake airway: 4.5m; The angle between the branch roadway (4) and the filling air intake roadway is 90°. Branch tunnel (4) length: 150~180m; Branch lane (4) width: 6.5~8m; The width of the coal pillar in the branch roadway (4) is 6.5~8m; The thickness of the upper layer in the branch tunnel (4) is 4.5m; The thickness of the sub-layer in the branch tunnel (4) is 1.5~3.5m.

10. The method for high-recovery, high-roof-reach mining of thick coal seams using a roadway-type strip backfilling method according to claim 2, characterized in that, When the EBM300M-2A chain cutterhead (12) is used for layered mining in the branch roadway (4), local ventilation is used; When the EML340 continuous coal mining machine (11) is used for layered mining in the branch roadway (4), it adopts full air pressure ventilation.

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