A spiral drill coal mining method based on hysteresis paste filling

Abstract

The application discloses a spiral drill coal mining method based on hysteresis paste filling and belongs to the field of coal mining. In view of the problems of low recovery rate of traditional spiral drill coal mining method and easy occurrence of surrounding rock instability and gas accumulation hidden danger, high-position and low-position air return roadways are arranged on both sides of a machine rail roadway of a thin coal seam working face, a spiral drill coal mining machine is used to drill out coal by sequentially performing an upward inclined through drilling and a downward inclined blind hole drilling, the hole is classified and sealed after the drilling tool is withdrawn, a space hysteresis interval filling mode is used, paste filling materials are continuously pumped into the target drill hole until micro-positive pressure roof contact is achieved, parallel circulation operation of drilling and mining out coal in front and hole sealing and hysteresis grouting in back is realized. The application uses filling body with high early strength and a narrow coal pillar to construct a coal-filling combined support system, effectively controls roof subsidence, eliminates post-mining gas hidden danger, greatly improves the working face recovery rate to more than 80%, and realizes safe, efficient and green mining under the condition of complex soft and weak surrounding rock.

Description

Technical Field

[0001] This invention belongs to the field of coal mining and relates to a high extraction rate mining method for thin and extremely thin coal seams, specifically a spiral drilling coal mining method based on delayed paste filling. Background Technology

[0002] Spiral drilling is a specialized coal mining technique suitable for recovering thin coal seams, marginal coal seams, and irregular coal pillars. Its core process involves using a high-powered spiral drilling machine to drive the drill rod and drill bit through the coal seam between two parallel roadways positioned within the coal seam. Simultaneously, rotating spiral blades continuously transport the broken coal into the roadway. This method offers advantages such as low equipment investment, relatively simple process, low roadway excavation rate, and no need for personnel to enter the goaf.

[0003] However, traditional spiral drilling coal mining technology has several inherent defects that severely restrict its further improvement in technical and economic benefits and safety. These defects are mainly reflected in the following three aspects: First, the large-scale retention of coal pillars between boreholes and between borehole groups leads to serious resource waste, with the overall extraction rate of the working face typically only reaching 40%-60%. Second, the numerous parallel boreholes create artificially created weak zones and cavities in the coal seam, easily causing plastic damage and creep of the surrounding coal pillars. Simultaneously, this leads to slow roof subsidence, delamination, and even collapse, and the resulting dynamic load further exacerbates the deformation and damage of adjacent roadways, significantly increasing the maintenance costs and difficulty of the roadways. Third, the closed boreholes left after mining easily become "gas storage chambers" for gas accumulation. These accumulated high-concentration gas deposits may suddenly erupt through coal and rock fissures, causing gas exceedances in the roadway airflow, and in severe cases, even triggering catastrophic accidents such as gas explosions.

[0004] Currently, the industry lacks a systematic solution to the aforementioned problems. Conventional methods often involve passively sealing the borehole opening, but this fails to address the core issues of resource loss and surrounding rock control. Therefore, a new technological approach is urgently needed to fundamentally overcome the shortcomings of traditional auger drilling in coal mining, achieving a significant increase in extraction rate and effective control of the surrounding rock while ensuring construction safety and efficiency. Summary of the Invention

[0005] To overcome the shortcomings of the above-mentioned spiral drilling coal mining in terms of resource loss and surrounding rock control, the present invention provides a spiral drilling coal mining method based on delayed paste filling.

[0006] This invention is applicable to thin and extremely thin coal seams with a thickness of 0.3m-1.3m, specifically for complex geological and environmental conditions such as poor roof stability, strict requirements for surface subsidence control, and the presence of large quantities of industrial solid waste requiring urgent treatment. In terms of specific layout, a machine track roadway is set up along the middle of the coal seam. The upper layer consists of the section between the machine track roadway and the high-level return airway, and mining is carried out at an upward angle from the machine track roadway towards the high-level return airway. The lower layer consists of the section between the machine track roadway and the low-level return airway, and mining is carried out at a downward angle from the machine track roadway towards the low-level return airway.

[0007] This invention utilizes a delayed grouting and filling process to inject paste-based filling material into post-mining boreholes, achieving multiple objectives simultaneously: increasing extraction rate, controlling surrounding rock deformation, and eliminating safety hazards. By effectively filling post-mining boreholes with paste-based filling material, firstly, it replaces previously unextractable coal resources, significantly reducing the size of coal pillars and greatly improving extraction rate; secondly, it constructs a "coal-filling" joint bearing system, effectively controlling surrounding rock deformation and ensuring mining safety; thirdly, it significantly reduces the space for underground gas accumulation, substantially lowering safety hazards; fourthly, it enables parallel mining and filling operations, optimizing construction technology and efficiency; and fifthly, it facilitates the large-scale consumption of bulk industrial solid waste, practicing green and environmentally friendly principles.

[0008] This invention provides a spiral drilling method for coal mining based on delayed paste filling, comprising the following steps: A. A machine track roadway is arranged along the coal seam direction in the thin coal seam working face, and a high-level return air roadway and a low-level return air roadway are arranged on both sides of the machine track roadway; initially, a filling pipe is arranged in each of the machine track roadway and the high-level return air roadway, and the spiral drilling coal mining machine and its supporting equipment are arranged in the machine track roadway. B. The spiral drilling coal mining machine advances obliquely from the machine track roadway to the high-level return airway until the drill bit is completely penetrated and emerges from the side of the high-level return airway, forming a complete through borehole; a solid coal pillar is left between adjacent through boreholes; while drilling, the spiral drilling coal mining machine transports coal to one side of the machine track roadway, and after coal is extracted, the drilling tool is withdrawn. C. After the drilling tool is withdrawn, according to the filling design, the two sides of the borehole (the side of the machine rail tunnel and the side of the high-level return air tunnel) should be sealed immediately to achieve the closure of the borehole. D. Using an intermittent filling mode, paste filling material is injected into the through boreholes where coal has been produced. The filling operation is spatially delayed compared to the current drilling and production face. E. Maintain a constant pumping speed to continuously pump the paste filling material into the target through borehole until the borehole is full and connected to the top. Stop grouting and seal the pipe opening. F. Repeat steps B to E, and carry out parallel operations of drilling and coal extraction, orifice classification and plugging and delayed interval grouting along the working face advance direction until the entire inclined mining on this side is completed. G. After completing the inclined mining on one side, the machine track roadway will be used as the machine track roadway for the next mining stage; the spiral drilling coal mining machine will turn around in place and begin inclined mining of the coal body on the other side of the machine track roadway. H. The spiral drilling coal mining machine advances obliquely from the machine track roadway to the low-level return airway until the drill bit reaches the set stop position, forming a blind hole that is not penetrated; a solid coal pillar is left between adjacent blind holes; while drilling, the spiral drilling coal mining machine transports coal to one side of the machine track roadway, and after the coal is discharged, the drill bit is withdrawn. I. After the drill string is withdrawn, the opening of the blind hole should be sealed immediately according to the filling design to achieve the closure of the opening; J. Using an intermittent filling mode, paste filling material is injected into the blind holes where coal has been extracted. The filling operation is spatially delayed compared to the current drilling and mining face. K. Maintain a constant pumping speed to continuously pump the paste filling material into the target blind hole until the borehole is full and connected to the top. Stop grouting and seal the pipe opening. L. Repeat steps H to K, along the working face advancing direction, to carry out parallel operations of drilling and coal extraction, orifice classification and plugging, and delayed interval grouting, until the entire inclined mining on that side is completed.

[0009] Furthermore, in step B, the elevation angle of the inclined drilling ranges from 3° to 15°; the width of the formed through borehole is determined by the size and arrangement of the drill bit of the spiral drilling coal mining machine, and its width ranges from 0.3m to 3.0m; the width M of the solid coal pillar left between adjacent through boreholes is 0.5m to 1.5m.

[0010] Furthermore, in step C, the sealing and plugging are specifically classified as follows: for through boreholes without filling, quick-sealing sealing devices are installed at both the upper and lower openings (high-level return airway side and machine rail roadway side); for target boreholes planned to be filled, blind-end pressure-bearing sealing devices are installed at the lower opening (machine rail roadway side), and through-pressure-bearing sealing devices are installed at the upper opening (high-level return airway side).

[0011] Further, in step D, the interval filling mode specifically refers to the following: the spatial position of the filling operation lags behind the distance of K boreholes currently being drilled, and a mode of selecting a target borehole for filling is adopted every K boreholes, where K is 2 or 3; the injection of paste filling material specifically refers to the injection of paste filling material into the target borehole through the grouting pipe on the borehole grouting pipe of the pressure-bearing sealed device on the high-level return airway side.

[0012] Furthermore, in step E, the criterion for determining that the paste filling material is full and connected to the top is: as the liquid level rises, the air in the hole is discharged from the exhaust pipe on the high-level return airway side. When the exhaust pipe overflows and the hole reaches a slight positive pressure, it is determined that the hole is full and connected to the top.

[0013] Further, in step H, the downward drilling angle ranges from 3° to 15°; the width of the blind hole formed is determined by the drill bit size and arrangement of the spiral drilling coal mining machine, and its width ranges from 0.3m to 3.0m; the set stop position is at a distance of L = 2m to 5m from the sidewall of the low-level return airway, so as to retain this section of solid coal as a natural pressure-bearing retaining wall at the bottom of the hole; the width M of the solid coal pillar left between adjacent blind holes is 0.5m to 1.5m.

[0014] Furthermore, in step I, the sealing and plugging are specifically classified as follows: for unfilled cavity blind holes, a quick-sealing sealing device is installed on one side of the hole (railway side); for target blind holes that are planned to be filled, a through-pressure sealing device is installed on one side of the hole (railway side).

[0015] Further, in step J, the interval filling mode specifically refers to the following: the spatial position of the filling operation lags behind the distance of K boreholes currently being drilled, and a mode of selecting a target blind hole for filling is adopted every K boreholes, where K is 2 or 3; the injection of paste filling material specifically refers to the injection of paste filling material into the target blind hole through the grouting pipe on the through-type pressure-bearing sealed device on the side of the machine track roadway.

[0016] Furthermore, in step K, the criterion for determining that the hole is full and connected to the top is: as the liquid level rises, the air inside the hole is discharged from the exhaust pipe on the side of the track roadway. When the exhaust pipe overflows with slurry and the hole reaches a slight positive pressure, it is determined that the hole is full and connected to the top.

[0017] Further, in steps D and J, the paste filling material is prepared by mixing the following components by mass percentage: 50%-65% coal gangue, 15%-25% fly ash, 5%-12% cement, 18%-25% water, and admixtures accounting for 0.5%-1.5% of the total solid mass; the overall mass concentration of the mixed paste filling material is controlled between 75%-82%. The admixtures mainly include one or more of water-reducing agents, retarders, early-strength agents, polymer emulsions, or fiber materials.

[0018] Furthermore, the rapid sealing type sealing device is a solid masonry sealing wall; its structure and sealing process are as follows: at a predetermined depth at the borehole opening, bricks or coal gangue are used to build a full-section solid wall; and sealing mortar is applied to the outer surface of the solid wall and at the contact point with the surrounding coal and rock mass to form an airtight isolation barrier that blocks the gas from escaping.

[0019] Furthermore, both the blind-end pressure-bearing sealing device and the through-type pressure-bearing sealing device have a main body consisting of a double-layer flexible mold bag with built-in reinforcing bars. The blind-end pressure-bearing sealing device only includes a grouting pipe and a venting pipe connecting to the internal cavity of the mold bag. The through-type pressure-bearing sealing device, in addition to the blind-end pressure-bearing sealing device, also includes a drilling grouting pipe and a drilling venting pipe that completely penetrate the double-layer flexible mold bag and lead to the interior of the borehole to be filled. The sealing process involves pushing the double-layer flexible mold bag, pre-embedded with the aforementioned pipes, into the borehole to be filled. After the orifice reaches the predetermined depth, a high-flowability grout without coarse aggregate is first pumped into the orifice through the grouting pipe. Air inside the orifice is expelled through the vent pipe, causing the orifice to expand and tightly conform to the borehole wall. After solidification, it forms a high-strength solid anchoring retaining wall at the orifice of the borehole to be filled. The high-flowability grout includes, but is not limited to, pure cement grout, cement-fly ash grout, and high-water filling materials. A grout mix with micro-expansion and low-shrinkage characteristics is preferred to ensure that no shrinkage gaps are generated at the top of the orifice after the grout solidifies, and that it is tightly bonded to the top plate.

[0020] The beneficial effects of this invention are: (1) Significantly reduce the size of coal pillars and significantly improve the coal extraction rate: Traditional spiral drilling coal mining methods must leave a large number of coal pillars between holes to prevent roof collapse; however, since the present invention introduces filling bodies to participate in the bearing, the width of coal pillars between holes can be significantly reduced to 0.5m-1.5m in the mining design stage, thereby increasing the overall extraction rate of the working face from the traditional 40%-60% to more than 80%, which has considerable economic benefits; (2) Constructing a joint bearing structure to effectively control the deformation of the surrounding rock: The paste filling body of the present invention not only has a high roof contact rate but also has good early strength. Together with the reserved narrow coal pillar, it forms a "coal-filling" joint support system. This system timely and effectively inhibits the subsidence of the roof, avoids stress concentration in the mining area, and greatly improves the safety of mining. (3) Reduce underground cavities and significantly reduce safety hazards: This invention uses sealed grouting to partially replace and reduce the borehole cavities left after mining with solid materials, which fundamentally reduces the risk of gas outbursts and water inrushes, and greatly improves the ventilation and safe production environment of the mine. (4) Parallel mining and filling operations, simple and efficient process: The present invention adopts the delayed filling mode, which realizes that the front drilling and coal output and the rear grouting and filling do not interfere with each other. This process is easy to implement in the existing spiral drilling working face, with high construction efficiency and extremely low cost. (5) Solid waste resource utilization and practice of green environmental protection concept: This invention uses bulk industrial solid waste such as coal gangue and fly ash as the main backfill aggregate, which significantly reduces backfill cost and effectively solves the environmental pollution problem caused by surface gangue piles, which is in line with the concept of green mine and sustainable development. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the mining area layout during the inclined mining stage of this invention; Figure 3 This is a schematic diagram of the mining area layout during the inclined mining stage of this invention; Figure 4 This is a schematic cross-sectional view of the inclined mining process of the present invention; Figure 5 This is a schematic cross-sectional view of the inclined mining process of the present invention; Figure 6 This is a schematic diagram of the planar structure of the intermittent filling morphology of the present invention; Figure 7 This is a schematic diagram showing the usage state of the rapid sealing device of the present invention; Figure 8 This is a schematic diagram of the operating state of the through-type pressure-bearing sealed device of the present invention; Figure 9 This is a schematic diagram of the through-type pressure-bearing sealed device of the present invention.

[0022] In the diagram: 1. Mining area return airway, 2. Mining area track airway, 3. Mining area transport airway, 4. Drilling and mining face machine track airway, 5. Drilling and mining face high-level return airway, 6. Drilling and mining face low-level return airway, 7. Spiral drilling coal mining machine, 8. Coal pillar, 9. Filling body, 10. Quick-sealing type sealing device, 11. Pressure-bearing type sealing device, 12. Filling pipe, 13. Solid coal, 14. Coal seam roof, 15. Coal seam floor, 16. Brick, 17. Molded bag grouting pipe, 18. Molded bag exhaust pipe, 19. Drill hole grouting pipe, 20. Drill hole exhaust pipe, 21. Tie bar. Detailed Implementation

[0023] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments. Example 1

[0024] This embodiment takes a working face in a coal mine as an example. This mine faces complex geological and environmental conditions, including strict requirements for surface subsidence control and the urgent need to treat large quantities of industrial solid waste (coal gangue and fly ash). The working face mines a thin coal seam with an average thickness of 0.8m and a dip angle of 10° (belonging to a gently dipping coal seam). The roof is sandy mudstone (belonging to a weak roof with poor stability and prone to collapse). The mining area where the working face is located consists of a macro-development system comprised of the mining area return airway 1, the mining area track airway 2, and the mining area transport airway 3.

[0025] This invention provides a spiral drilling method for coal mining based on delayed paste filling. The specific execution steps in this embodiment are as follows: Figure 1As shown, the specific explanation is as follows: A. A drilling and mining face track roadway 4 is arranged along the coal seam strike in the thin coal seam working face. On both sides of the drilling and mining face track roadway 4, a high-level return airway 5 is arranged for inclined mining, and a low-level return airway 6 is arranged for downward mining. Initially, a fixed filling pipe 12 is arranged in both the drilling and mining face track roadway 4 and the high-level return airway 5. The spiral drilling coal mining machine 7 and its supporting equipment are arranged within the drilling and mining face track roadway 4. Figure 2 As shown; B. The spiral drilling coal mining machine 7 advances obliquely from the low-level drilling and mining face track roadway 4 towards the high-level return air roadway 5 of the drilling and mining face at an oblique angle of 10° until the drill bit is completely penetrated and emerges from the side of the high-level return air roadway 5 of the drilling and mining face, forming a complete through borehole. In this embodiment, the diameter of the spiral drilling coal mining machine 7 drill bit is 0.8m, and a three-drill bit arrangement is adopted. The width of the through borehole (approximately a long strip hole) is 2.0m. A coal pillar 8 with a width of M=0.5m is left between adjacent through boreholes. While drilling, the spiral drilling coal mining machine 7 transports coal to one side of the drilling and mining face track roadway 4. After the coal is extracted, the drilling tool is withdrawn. C. After the drill string is withdrawn, the two ends of the through borehole should be immediately sealed and plugged according to the filling design, such as... Figure 2 and Figure 4 As shown; the specific sealing process is as follows: For unfilled through boreholes, rapid-sealing devices 10 are installed at both the upper and lower openings. The rapid-sealing device 10 is a solid masonry sealing wall. At a predetermined depth at the borehole opening, bricks 16 are used to form a full-section solid wall. Sealing mortar is applied to the outer surface of this solid wall and at the joints where it contacts the surrounding coal and rock mass, forming an airtight barrier to prevent gas leakage. (See...) Figure 7 As shown; For the target borehole to be filled, a blind-end pressure-bearing sealing device 11 is installed at its lower borehole opening (side of the machine track roadway), and a through-type pressure-bearing sealing device 11 is installed at its upper borehole opening (side of the high-level return airway). Both the blind-end pressure-bearing sealing device 11 and the through-type pressure-bearing sealing device 11 are double-layered flexible formwork bags with built-in reinforcing bars 21. The blind-end pressure-bearing sealing device 11 only includes a formwork bag grouting pipe 17 and a formwork bag venting pipe 18 that connect to the internal cavity of the formwork bag. The through-type pressure-bearing sealing device 11, based on the blind-end pressure-bearing sealing device, also includes a fully penetrating... The double-layer flexible manhole cover is inserted into the borehole through a grouting pipe 19 and a vent pipe 20. The sealing process is as follows: After pushing the double-layer flexible manhole cover with pre-embedded pipes into the borehole opening, cement-fly ash slurry is first pumped into the manhole cover through the grouting pipe 17 using a small, mobile grouting device. Air inside the manhole is discharged through the vent pipe 18, causing the manhole cover to expand and tightly conform to the borehole wall. After solidification, a high-strength solid anchoring retaining wall is formed at the borehole opening, serving as the pressure-bearing end for subsequent micro-positive pressure filling. See [link to relevant documentation]. Figure 8 As shown; Figure 9 The structure of a through-type pressure-bearing sealed device is shown.

[0026] D. Using an intermittent filling method, inject paste filling material into the through borehole where coal has been extracted (ultimately forming filling body 9). For example... Figure 6 As shown; In this embodiment, the filling operation lags behind the currently drilling through borehole by a distance of K=2 boreholes in spatial location, and a target through borehole is selected for filling every K=2 boreholes. During filling, paste filling material is injected into the target borehole through the grouting pipe 19 on the borehole grouting pipe 19 on the high-level return airway 5 side of the drilling and mining face, connecting the filling pipe 12 to the pressure-bearing sealed device 11. The paste filling material is made by mixing 50% coal gangue, 20% fly ash, 8% cement, and 22% water by mass percentage, and additionally adding 1.0% water-reducing agent and retarder by the total solid mass. The overall mass concentration of the mixed paste filling material is controlled at 78%. E. Maintain a uniform and continuous pumping speed to fill the target through borehole with paste filling material; as the liquid level rises, the air in the hole is discharged from the borehole exhaust pipe 20 on the side of the high-level return airway 5 of the drilling and mining face. When the slurry overflows from the borehole exhaust pipe 20 and the hole reaches a slight positive pressure, it is determined that the slurry has fully squeezed the coal seam roof 14 to achieve complete roof contact. Stop grouting and seal the pipe opening. F. Repeat steps B to E, and carry out parallel operations of drilling and coal extraction, orifice classification and plugging and delayed interval grouting along the working face advance direction until the entire inclined mining on this side is completed. G. After completing the inclined mining on one side, the drilling and mining face machine rail roadway 4 is reused as the machine rail roadway for the next mining stage; the spiral drilling coal mining machine 7 turns its direction in place and begins to mine the coal body on the other side of the drilling and mining face machine rail roadway 4 at an inclined angle of 10°. H. The spiral drilling coal mining machine 7 advances obliquely from the machine track roadway 4 of the drilling and mining face towards the low-level return airway 6 of the drilling and mining face until the drill bit reaches a distance of L=3.0m from the side wall of the low-level return airway and stops. This section of solid coal 13 with a thickness of 3.0m is retained as a natural pressure-bearing retaining wall at the bottom of the hole, forming a blind hole that is not penetrated. Due to the use of a three-drill bit arrangement, the hole width of the blind hole is 2.0m. A coal pillar 8 with a width of M=0.5m is also left between adjacent blind holes. After the coal is extracted, the drilling tools are withdrawn. I. After the drill string is withdrawn, immediately seal and plug one side of the blind hole (the side of the machine track): for hollow blind holes that are not to be filled, install a quick-sealing type sealing device 10; for target blind holes that are to be filled, install a through-pressure type sealing device 11. J. Using the same K=2 interval filling mode as the inclined section, paste filling material is injected into the target blind hole by connecting the grouting pipe 19 on the pressure-bearing sealed device 11 on the four sides of the drilling and mining face track roadway through the docking drilling and mining face. K. Maintain a uniform and continuous pumping speed for the paste filling material. As the liquid level rises, the air in the hole is discharged through the borehole exhaust pipe 20 on the side of the drilling and mining face machine track roadway 4. When the borehole exhaust pipe 20 overflows with slurry and the hole reaches a slight positive pressure, it is determined that the hole is filled and tightly adheres to the coal seam roof 14. Grouting is stopped and the pipe opening is sealed. L. Repeat steps H to K, along the working face advancing direction, to carry out parallel operations of drilling and coal extraction, orifice classification and plugging, and delayed interval grouting, until the entire inclined mining on that side is completed.

[0027] The paste filling material of the present invention not only has a high roof contact rate and good early strength, but also forms a "coal-filling" joint support system together with the reserved narrow coal pillar. This system timely and effectively inhibits the subsidence of the roof, avoids stress concentration in the mining area, and greatly improves mining safety. Moreover, it increases the overall extraction rate of the working face to more than 80%, resulting in considerable economic benefits.

Claims

1. A spiral drilling method for coal mining based on delayed paste filling, characterized in that... Includes the following steps: A. A machine track roadway is arranged along the coal seam direction in the thin coal seam working face, and a high-level return air roadway and a low-level return air roadway are arranged on both sides of the machine track roadway; initially, a filling pipe is arranged in each of the machine track roadway and the high-level return air roadway, and the spiral drilling coal mining machine and its supporting equipment are arranged in the machine track roadway. B. The spiral drilling coal mining machine advances obliquely from the machine track roadway to the high-level return airway until the drill bit is completely penetrated and emerges from the side of the high-level return airway, forming a complete through borehole; a solid coal pillar is left between adjacent through boreholes; while drilling, the spiral drilling coal mining machine transports coal to one side of the machine track roadway, and after coal is extracted, the drilling tool is withdrawn. C. After the drill string is withdrawn, according to the filling design, the two sides of the borehole should be sealed immediately to achieve the closure of the borehole openings. D. Using an intermittent filling mode, paste filling material is injected into the through boreholes where coal has been produced. The filling operation is spatially delayed compared to the current drilling and production face. E. Maintain a constant pumping speed to continuously pump the paste filling material into the target through borehole until the borehole is full and connected to the top. Stop grouting and seal the pipe opening. F. Repeat steps B to E, and carry out parallel operations of drilling and coal extraction, orifice classification and plugging and delayed interval grouting along the working face advance direction until the entire inclined mining on this side is completed. G. After completing the inclined mining on one side, the machine track roadway will be used as the machine track roadway for the next mining stage; the spiral drilling coal mining machine will turn around in place and begin inclined mining of the coal body on the other side of the machine track roadway. H. The spiral drilling coal mining machine advances obliquely from the machine track roadway to the low-level return airway until the drill bit reaches the set stop position, forming a blind hole that is not penetrated; a solid coal pillar is left between adjacent blind holes; while drilling, the spiral drilling coal mining machine transports coal to one side of the machine track roadway, and after the coal is discharged, the drill bit is withdrawn. I. After the drill string is withdrawn, the opening of the blind hole should be sealed immediately according to the filling design to achieve the closure of the opening; J. Using an intermittent filling mode, paste filling material is injected into the blind holes where coal has been extracted. The filling operation is spatially delayed compared to the current drilling and mining face. K. Maintain a constant pumping speed to continuously pump the paste filling material into the target blind hole until the borehole is full and connected to the top. Stop grouting and seal the pipe opening. L. Repeat steps H to K, along the working face advancing direction, to carry out parallel operations of drilling and coal extraction, orifice classification and plugging, and delayed interval grouting, until the entire inclined mining on that side is completed.

2. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, The thickness of the thin coal seam is 0.3m-1.3m.

3. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, In step B, the elevation angle of the inclined drilling ranges from 3° to 15°; the width of the formed through borehole is determined by the size of the drill bit of the spiral drilling coal mining machine and its arrangement, and its width ranges from 0.3m to 3.0m; the width M of the solid coal pillar left between adjacent through boreholes is 0.5m to 1.5m.

4. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, In step C, the sealing and plugging are specifically classified as follows: for cavity through boreholes that are not filled, quick-sealing sealing devices are installed at both the upper and lower openings; for target boreholes that are planned to be filled, blind-end pressure-bearing sealing devices are installed at the lower opening and through-pressure-bearing sealing devices are installed at the upper opening. In step I, the sealing and plugging are specifically classified as follows: for blind holes in cavities that are not to be filled, a quick-sealing type sealing device is installed on one side of the hole; for target blind holes that are planned to be filled, a through-pressure type sealing device is installed on one side of the hole.

5. The spiral drilling coal mining method based on delayed paste filling according to claim 4, characterized in that, In step D, the interval filling mode specifically refers to the following: the spatial position of the filling operation lags behind the distance of K boreholes of the currently drilling through borehole, and a target through borehole is selected for filling every K boreholes, where K is 2 or 3; the injection of paste filling material specifically refers to the following: paste filling material is injected into the target borehole through the grouting pipe on the through pressure-bearing sealed device on the high-level return airway side; In step J, the interval filling mode specifically means that the spatial position of the filling operation lags behind the distance of K holes currently being drilled, and a target blind hole is selected for filling every K holes, where K is 2 or 3; the injection of paste filling material specifically means that paste filling material is injected into the target blind hole through the grouting pipe on the through-type pressure-bearing sealed device on the side of the machine track roadway.

6. The spiral drilling coal mining method based on delayed paste filling according to claim 4, characterized in that, The rapid sealing type airtight device is a solid masonry airtight wall; the sealing process is as follows: at a predetermined depth at the borehole opening, bricks or coal gangue are used to build a full-section solid wall; and sealing mortar is applied to the outer surface of the solid wall and at the contact point with the surrounding coal and rock mass to form an airtight isolation barrier that blocks the gas from escaping.

7. The spiral drilling coal mining method based on delayed paste filling according to claim 4, characterized in that, Both the blind-end pressure-bearing sealing device and the through-pressure-bearing sealing device have a double-layer flexible formwork bag with built-in reinforcing bars as their main body. The blind-end pressure-bearing sealing device only includes a formwork bag grouting pipe and a formwork bag venting pipe that connect to the internal cavity of the formwork bag. The through-pressure-bearing sealing device, based on the blind-end pressure-bearing sealing device, also includes a borehole grouting pipe and a borehole venting pipe that completely penetrate the double-layer flexible formwork bag and lead to the interior of the borehole to be filled. The sealing process is as follows: after the double-layer flexible formwork bag with the above-mentioned pipes is pushed into the borehole opening to a predetermined depth, a high-flowability grout without coarse aggregate is first pumped into the formwork bag through the formwork bag grouting pipe. The air inside the formwork bag is discharged through the formwork bag venting pipe, causing the formwork bag to expand and tightly conform to the borehole wall. After solidification, a high-strength solid anchoring retaining wall is formed at the borehole opening to be filled.

8. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, In step E, the standard for determining that the paste filling material is full and connected to the top is: as the liquid level rises, the air in the hole is discharged from the exhaust pipe on the side of the high-level return airway. When the exhaust pipe overflows and the hole reaches a slight positive pressure, it is determined that the hole is full and connected to the top. In step K, the criterion for determining that the hole is full and connected to the top is: as the liquid level rises, the air in the hole is discharged from the exhaust pipe on the side of the track roadway. When the exhaust pipe overflows and the hole reaches a slight positive pressure, it is determined that the hole is full and connected to the top.

9. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, In step H, the downward angle of the inclined drilling ranges from 3° to 15°; the width of the blind hole formed is determined by the size and arrangement of the drill bit of the spiral drilling coal mining machine, and its width ranges from 0.3m to 3.0m; the set stop position is at a distance of L = 2m to 5m from the side of the low-level return airway, so as to retain this section of solid coal as a natural pressure-bearing retaining wall at the bottom of the hole; the width M of the solid coal pillar left between adjacent blind holes is 0.5m to 1.5m.

10. The spiral drilling coal mining method based on delayed paste filling according to claim 1, characterized in that, The paste filling material is prepared by mixing the following components by mass percentage: 50%-65% coal gangue, 15%-25% fly ash, 5%-12% cement, 18%-25% water, and 0.5%-1.5% additives by mass percentage of the total solid phase; the mass concentration of the mixed paste filling material is 75%-82%; the additives include one or more of water-reducing agents, retarders, early-strength agents, polymer emulsions, or fiber materials.

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