In-situ jet flow breaking-negative pressure coal slurry back suction extreme environment mining method and system

Abstract

This invention discloses an extreme environment mining method and system using in-situ jet crushing and negative pressure coal slurry back suction, relating to the field of intelligent coal mining and resource recovery technology. The method includes precise exploration modeling; system deployment and lowering, lowering an integrated drilling jet device to form jet pipelines and slurry suction pipelines; isolation and stabilization; in-situ jet crushing and slurry preparation; negative pressure coal slurry back suction and lifting; solid-liquid separation and closed-loop circulation. The system includes an integrated drilling jet device, a mobile positioning system, a negative pressure back suction system, a PLC intelligent control system, a jet circulation system, a grouting system, and a solid-liquid separation system. The extreme environment mining method and system using in-situ jet crushing and negative pressure coal slurry back suction provided by this invention can achieve in-situ crushing and slurry preparation underground, continuous negative pressure back suction and lifting, and can achieve collaborative operation with closed-loop circulation of water media.

Description

Technical Field

[0001] This invention relates to the field of intelligent coal mining and resource recovery technology, and in particular to an extreme environment mining method and system of in-situ jet crushing-negative pressure coal slurry back suction. Background Technology

[0002] In the coal mining sector, large amounts of residual coal resources still exist in old mining areas, goaf areas, and abandoned roadways. The recovery and utilization of these resources is crucial for improving the overall utilization rate of coal resources and ensuring energy supply. However, these areas containing residual coal resources represent typical extreme environments in coal mining, characterized by complex spatial morphology, unclear geometric boundaries, and loose, fractured surrounding rock prone to collapse. Furthermore, the complex hydrogeological conditions present risks of water inrush, gas accumulation, and poisoning and explosions, making these areas challenging for coal resource recovery.

[0003] In existing technologies, the recovery of legacy coal resources in such extreme environments still primarily relies on personnel-accessible re-mining, supplemented by localized mechanized operations or mining after reinforcement of small areas. Under this model, workers must enter high-risk areas, facing multiple safety threats such as water inrush, gas leaks, and surrounding rock collapses, resulting in extremely high personnel exposure risks. Furthermore, environmental constraints make operational organization difficult, hindering continuous mining and leading to low coal extraction efficiency. Simultaneously, existing mining technologies struggle to establish a closed-loop operation process of continuous crushing, conveying, and recovery in high-risk goaf areas. The mining process is highly intermittent, requiring multiple manual handling and secondary crushing operations, further reducing mining efficiency and increasing operating costs.

[0004] In addition, traditional coal recovery technology results in a large amount of coal-water discharge during operation, which not only causes serious waste of water resources but also easily leads to pollution of the surrounding water environment. At the same time, the demand for water replenishment of the working medium required for mining is high, which is contrary to the current coal industry's green, low-carbon, energy-saving and consumption-reducing mining development concept.

[0005] Some existing technologies attempt to reduce personnel entering the mine through mechanization, but are limited by the complex geological conditions of extreme environments, making it impossible to achieve precise positioning and efficient crushing of the target coal body. Furthermore, the lack of suitable negative pressure conveying technology hinders the continuous lifting and recovery of coal slurry. Simultaneously, the absence of an effective working medium recycling system fails to address water waste and pollution issues. Other technologies treat goaf areas with grouting reinforcement before mining, but the grouting sealing effect lacks standardized verification methods, failing to provide a stable working boundary for subsequent mining operations. This leads to problems such as negative pressure leakage and harmful gas cross-flow, causing mining operations to be interrupted, and compromising safety and continuity.

[0006] In summary, existing technologies for recovering legacy coal resources suffer from numerous problems under extreme environments, including high personnel safety risks, weak continuous mining capabilities, low resource recovery efficiency, unreasonable water resource utilization, and poor operational stability. These limitations make it difficult to meet the practical needs of safe, efficient, and environmentally friendly recovery of legacy coal resources in extreme environments such as old mining areas and goaf areas. Therefore, there is an urgent need to design an unmanned recovery scheme that can achieve in-situ crushing and slurry preparation, continuous negative pressure back-suction lifting, and closed-loop circulation of water media under ground control conditions, in order to improve safety, continuity, and resource utilization efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide an extreme environment mining method and system for in-situ jet crushing and negative pressure coal slurry back suction, so as to solve the problems existing in the prior art. It can realize in-situ crushing and slurry preparation in the mine, continuous negative pressure back suction and lifting, and can realize closed-loop circulation and coordinated operation with water medium.

[0008] To achieve the above objectives, the present invention provides the following solution: This invention provides an extreme environment mining method using in-situ jet crushing and negative pressure coal slurry backflow, comprising: Precise exploration and modeling were used to investigate the spatial morphology, coal distribution, and disaster factors of old mining areas and goaf areas, and to construct a three-dimensional digital model. The system is deployed and installed by setting up a jet circulation system, a negative pressure back suction system, a grouting system, a solid-liquid separation system and a PLC intelligent control system on the ground, and then installing an integrated drilling jet device through the working borehole to form a jet pipeline and a grout suction pipeline channel. For sealing and stabilizing, the grouting system is activated to seal and stabilize the cracks around the borehole and the target work area, forming a closed or semi-closed work boundary that meets the requirements of jet breaking and negative pressure back suction. In-situ jet crushing and slurry preparation involves pressurizing the working medium through a jet circulation system and then transporting it through a jet pipeline to an integrated drilling jet device in the well to form a jet. This jet then performs scanning or fixed-point impact, cutting, and crushing on the target coal body, mixing the crushed coal body with the working medium to form a coal slurry. The negative pressure coal slurry back suction and lifting system is activated to form a stable negative pressure field in the suction pipeline channel, so that the coal slurry enters the suction pipeline through suction filtration and is lifted to the ground collection end; Solid-liquid separation and closed-loop circulation: the ground collection end performs solid-liquid separation on the lifting coal slurry, recovers the coal, and the separated water is purified and reused in the jet circulation system to achieve closed-loop circulation of the working medium.

[0009] In one embodiment, the sealing and stabilization step includes grouting and reinforcing the borehole annulus and the fracture zone of the goaf in segments to suppress water inrush, suppress the flow of harmful gases and improve the stability of the surrounding rock. After the target negative pressure is established in the grouting pipeline, the negative pressure decay does not exceed a preset threshold within a preset time, or the leakage rate does not exceed a preset threshold.

[0010] In one embodiment, the jet is a continuous jet or a pulsed jet; the working medium is water or a solution containing additives.

[0011] In one embodiment, the slurry preparation process in the in-situ jet crushing and slurry preparation step maintains the coal slurry concentration within a range that can be stably transported by adjusting the jet flow rate and the back suction flow rate, and forms a coal slurry collection zone at the bottom of the goaf or in a designated collection area.

[0012] In one embodiment, in the in-situ jet crushing and slurry preparation step and the negative pressure coal slurry back suction lifting step, the solid phase mass fraction of the coal slurry is maintained at 10-40% by coordinating the jet flow rate and the back suction flow rate, and the maximum particle size in the coal slurry does not exceed 10-30mm.

[0013] In one embodiment, a slurry suction filter screen is provided at the inlet of the slurry suction pipe, and the filter screen has a pore size of 5-30mm; the negative pressure back suction system makes the negative pressure at the inlet of the slurry suction pipe -10~-90kPa.

[0014] In one embodiment, the solid-liquid separation system includes at least one solid-liquid separator and a spiral solid-liquid separator or an inclined spiral solid-liquid separator, so that the coal and circulating water are continuously separated and enter the coal box and water box respectively; the separated water is reused in the jet circulation system after sedimentation, filtration or purification, with a reuse rate of not less than 70%.

[0015] In one embodiment, during the mining process, the jet pressure, negative pressure intensity, coal slurry flow rate, pressure difference, and surrounding rock stability parameters are monitored in real time based on sensors, and the PLC intelligent control system performs remote linkage parameter adjustment or triggers safety protection such as shutdown, pressure relief, blockage removal, and grouting reinforcement.

[0016] This invention also provides an in-situ jet crushing-negative pressure coal slurry back-suction extreme environment mining system applied to the aforementioned in-situ jet crushing-negative pressure coal slurry back-suction extreme environment mining method. The system includes an integrated drilling jet device, a mobile positioning system, a negative pressure back-suction system, a PLC intelligent control system, a jet circulation system, a grouting system, and a solid-liquid separation system. The jet circulation system, negative pressure back-suction system, grouting system, solid-liquid separation system, PLC intelligent control system, and mobile positioning system are deployed on the ground of the proposed mining area. The mobile terminal of the system is equipped with the integrated drilling jet device, which is used to move the integrated drilling jet device to a set position and enter the intended mining area through a borehole at that position; the grouting system, the negative pressure back suction system, and the jet circulation system are respectively connected to the integrated drilling jet device through pipelines; one end of the solid-liquid separation system is connected to the end of the negative pressure back suction system away from the integrated drilling jet device, and the other end of the solid-liquid separation system is connected to the end of the jet circulation system away from the integrated drilling jet device through a liquid pipeline.

[0017] In one embodiment, the integrated drilling jet device includes a drilling device, a grouting pipe, a jetting pipeline, a grout suction pipeline, and a column. The top of the column is connected to the moving end of the mobile positioning system, and the drilling device is located at the bottom of the column. A hydraulic cylinder is located inside the column, and a telescopic rod at the bottom of the hydraulic cylinder is connected to the drilling device. A third servo motor is located inside the drilling device, and a drill bit is connected to the third servo motor. The drill bit passes through the bottom of the drilling device. A working hole is formed inside the column, and the lower opening of the working hole is... Above the drilling device, the grouting pipe, jetting pipe, and suction pipe are integrated within the working hole, with the bottom opening of the grouting pipe extending to the bottom of the drilling device and spaced apart from the drill bit. A grouting screen is provided at the bottom opening of the grouting pipe, and a suction filter is provided at the bottom opening of the suction pipe. The jetting pipe and suction pipe extend through the lower opening of the working hole to the outside of the column. A displacement sensor is provided on the side wall of the column, and a pressure sensor, a coal mine detection sensor, and a geological monitoring sensor are provided at the bottom of the column.

[0018] In one embodiment, the mobile positioning system includes a horizontally arranged sliding rail on the ground, a sliding slider slidably connected to the sliding rail, and a second servo motor connected to the sliding slider. The second servo motor can drive the sliding slider to reciprocate along the length direction of the sliding rail. A horizontal track is fixedly connected to the sliding slider, and the horizontal track is perpendicular to the length direction of the sliding rail. A horizontal slider is provided on the horizontal track, and a driving device is connected to the horizontal slider to drive the horizontal slider to reciprocate along the horizontal track. A vertically arranged lead screw slide rail is provided on the horizontal slider, and a lead screw slider on the lead screw slide rail can move up and down along the lead screw slide rail. The lead screw slider is connected to the top of the column.

[0019] In one embodiment, the negative pressure back suction system includes a vacuum pump, a first delivery pump, and a filter connected in sequence via a high-pressure pipeline. The inlet of the vacuum pump is connected to the slurry suction pipeline via a pipeline, and the outlet of the filter is connected to the solid-liquid separation system via a pipeline. The jet circulation system includes a water tank, the outlet of which is connected to the jet pipeline via a plunger pump, and the inlet of which is connected to the liquid outlet of the solid-liquid separation system via a second delivery pump. The grouting system includes a grouting machine, which is connected to the grouting pipe via a third delivery pump.

[0020] The present invention achieves the following technical effects compared to the prior art: This invention relates to an in-situ jet crushing-negative pressure coal slurry back-suction mining method and system for extreme environments. During operation, personnel do not need to enter extremely dangerous environments such as old mine areas and goaf areas. In-situ crushing and back-suction hoisting are achieved through ground control, significantly reducing personnel exposure risks. Precise exploration modeling, directional borehole layout, and parameter setting enable target coal body positioning and controllable operation, improving the targeting and efficiency of residual coal resource recovery. Grouting and surrounding rock stabilization create closed or semi-closed operating boundaries, effectively suppressing water inrush and harmful gas flow, providing stable boundary conditions for negative pressure back-suction, and enhancing overall safety and continuous operation capability. High-pressure jet in-situ impact cutting and crushing followed by slurry preparation, combined with a negative pressure field driving continuous multiphase flow of coal slurry back-suction, achieves continuous output of crushing, slurry preparation, lifting, and separation, reducing intermittent handling and secondary crushing steps; slurry suction filtration combined with ground solid-liquid separation reduces the probability of pipeline blockage, improves back-suction stability, and enables rapid coal recovery; separated water purification and reuse form a closed-loop cycle, reducing water replenishment and discharge, improving water resource utilization efficiency, and meeting the requirements of green and low-carbon mining; sensor monitoring and PLC linkage control enable real-time monitoring, dynamic adjustment, and anomaly protection of key parameters, improving the reliability and repeatability of unmanned operation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the in-situ jet crushing-negative pressure coal slurry back-suction extreme environment mining system in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the arrangement of an extreme environment mining system for in-situ jet crushing-negative pressure coal slurry back suction in one or more embodiments of the present invention. Figure 3 This is a top view of an extreme environment mining system for in-situ jet crushing-negative pressure coal slurry back suction in one or more embodiments of the present invention. Figure 4 This is a schematic diagram of the overall structure of the integrated drilling jet device in one or more embodiments of the present invention; Figure 5 This is a front view of an integrated drilling jet device in one or more embodiments of the present invention; Figure 6 This is a cross-sectional view showing the internal structure distribution of an integrated drilling jet device in one or more embodiments of the present invention; Figure 7 This is a side view of an integrated drilling jet device in one or more embodiments of the present invention; Figure 8 This is a schematic diagram of the bottom structure of the drill bit of the integrated drilling jet device in one or more embodiments of the present invention; Figure 9 This is a top view of an integrated drilling jet device in one or more embodiments of the present invention; Figure 10 This is a schematic diagram of the extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction in one or more embodiments of the present invention; Figure 11 This is a schematic diagram of the in-situ fracturing jet mining process in coal and rock strata according to the present invention; Figure 12 This is a schematic diagram of the grouting process and the coal slurry transportation and separation process of the present invention.

[0023] In the diagram: 1-Integrated drilling jet device, 11-Drilling device, 111-Coal mine detection sensor, 112-Pressure sensor, 113-Geological monitoring sensor, 114-Drill bit, 12-Grouting pipe, 121-Grouting screen, 13-Jet pipeline, 14-Grouting pipeline, 141-Grouting filter, 15-Displacement sensor, 16-Column, 17-Hydraulic cylinder, 18-Third servo motor; 2-Mobile positioning system, 21-Mobile slider, 22- 23-Moving slide rail; 24-Second servo motor; 3-Screw slide rail; 3-Negative pressure back suction system; 31-Vacuum pump; 32-First conveying pump; 33-Filter; 34-Inclined spiral solid-liquid separator; 341-First servo motor; 35-Coal box; 36-High pressure pipeline; 4-PLC intelligent control system; 5-Jet circulation system; 51-Second conveying pump; 52-Water tank; 53-Plunger pump; 6-Grouting system; 61-Third conveying pump; 62-Grouting machine. Detailed Implementation

[0024] 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, and 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] The purpose of this invention is to provide an extreme environment mining method and system for in-situ jet crushing and negative pressure coal slurry back suction, so as to solve the problems existing in the prior art. It can realize in-situ crushing and slurry preparation in the mine, continuous negative pressure back suction and lifting, and can realize closed-loop circulation and coordinated operation with water medium.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1 like Figures 1-3As shown, this embodiment provides an in-situ jet crushing-negative pressure coal slurry backflow mining system for extreme environments, including an integrated drilling jet device 1, a mobile positioning system 2, a negative pressure backflow system 3, a PLC intelligent control system 4, a jet circulation system 5, a grouting system 6, and a solid-liquid separation system. The ground surface of the proposed mining area is equipped with the jet circulation system 5, the negative pressure backflow system 3, the grouting system 6, the solid-liquid separation system, the PLC intelligent control system 4, and the mobile positioning system 2. The mobile positioning system 2 has an integrated drilling jet device 1 mounted on its mobile end, which moves the integrated drilling jet device 1 to a set position and enters the proposed mining area through a borehole at that position. The grouting system 6, the negative pressure backflow system 3, and the jet circulation system 5 are respectively connected to the integrated drilling jet device 1 via pipelines. One end of the solid-liquid separation system is connected to the end of the negative pressure backflow system 3 away from the integrated drilling jet device 1, and the other end of the solid-liquid separation system is connected to the end of the jet circulation system 5 away from the integrated drilling jet device 1 via a liquid pipeline.

[0028] The mobile positioning system 2 includes a horizontally arranged sliding rail 22 on the ground, a sliding slider 21 slidably connected to the sliding rail 22, and a second servo motor 23 connected to the sliding slider 21. The second servo motor 23 can drive the sliding slider 21 to reciprocate along the length direction of the sliding rail 22. A horizontal track is fixedly connected to the sliding slider 21, and the horizontal track is perpendicular to the length direction of the sliding rail 22. A horizontal slider is provided on the horizontal track, and a driving device is connected to the horizontal slider. The driving device can be a screw and nut pair structure or a drive motor, to drive the horizontal slider to reciprocate along the horizontal track. A vertically arranged screw and nut rail 24 is provided on the horizontal slider. The screw and nut rail 24 is a screw and nut pair structure, and its nut is connected to the screw and slider on the screw and nut rail 24, so that the screw and slider can move up and down along the screw and nut rail 24. The screw and slider is connected to the top of the column 16. The negative pressure back suction system 3 includes a vacuum pump 31, a first delivery pump 32, and a filter 33, which are connected in sequence through a high-pressure pipeline 36. The inlet of the vacuum pump 31 is connected to the slurry suction pipeline 14 through a pipeline, and the outlet of the filter 33 is connected to the solid-liquid separation system through a pipeline. The jet circulation system 5 includes a water tank 52. The outlet of the water tank 52 is connected to the jet pipeline 13 through a plunger pump 53, and the inlet of the water tank 52 is connected to the liquid outlet of the solid-liquid separation system through a second delivery pump 51. The grouting system 6 includes a grouting machine 62, which is connected to the grouting pipe 12 through a third delivery pump 61. The solid-liquid separation system includes an inclined spiral solid-liquid separator 34, which is connected to a coal box 35 via a conveying pipe equipped with a first servo motor 341. The separated solids are conveyed into the coal box 35, and the separated liquids are conveyed into a water tank 52 via a second conveying pump 51. The integrated drilling jet device 1, the mobile positioning system 2, the negative pressure back suction system 3, the jet circulation system 5, the grouting system 6, and the solid-liquid separation system are controlled by a PLC intelligent control system 4, which receives and sends electrical signals for linkage control. The vacuum pump 31 provides the power source for the negative pressure field.

[0029] Example 2 like Figures 4-9As shown, this embodiment provides an integrated drilling jet device 1 structure, applied to the in-situ jet crushing-negative pressure coal slurry back-suction extreme environment mining system in Embodiment 1. Its structure includes a drilling device 11, a grouting pipe 12, a jet pipeline 13, a slurry suction pipeline 14, and a column 16. The top of the column 16 is connected to the moving end of the mobile positioning system 2, and the bottom of the column 16 is equipped with the drilling device 11. A hydraulic cylinder 17 is installed inside the column 16, and the telescopic rod at the bottom of the hydraulic cylinder 17 is connected to the drilling device 11, enabling it to drive the drilling device 11 to move up and down. A third servo motor 18 is installed inside the drilling device 11, and the third servo motor 18 is connected to a drill bit 114, enabling it to drive the drill bit 114 to rotate. The drill bit 114 passes through the bottom of the drilling device 11. A working hole is provided inside the column 16. The lower opening of the working hole is located above the drilling device 11. The grouting pipe 12, the jetting pipe 13, and the suction pipe 14 are integrated in the working hole. The bottom opening of the grouting pipe 12 extends to the bottom of the drilling device 11 and is spaced apart from the drill bit 114. The drill bit 114 can rotate independently on the drilling device 11. The grouting pipe 12 will not interfere with the working process of the drill bit 114. The fixed end of the hydraulic cylinder 17 is vertically fixed inside the column 16. The telescopic rod of the hydraulic cylinder 17 is connected to the drilling device 11. By driving the drilling device 11 to move up and down as a whole, the axial feed and retraction of the drill bit 114 are realized. The third servo motor 18 is set inside the drilling device 11 and is directly connected to the drill bit 114 to drive the drill bit 114 to rotate. During operation, the hydraulic cylinder 17 provides propulsion force and displacement adjustment, while the third servo motor 18 provides rotational torque. Together, they enable the drill bit 114 to perform fixed-point drilling and mechanical crushing of the target coal body, and coordinate with the high-pressure jet crushing process to achieve efficient crushing of the target coal body and subsequent slurry preparation and back suction. While the drill bit 114 rotates, the third servo motor 18 can also achieve in-situ high-pressure jet crushing rotation, improving the crushing and slurry preparation area. The bottom opening of the grouting pipe 12 is equipped with a grouting screen 121, and the bottom opening of the slurry suction pipe 14 is equipped with a slurry suction filter 141. The jet pipe 13 and the slurry suction pipe 14 extend through the lower opening of the working hole to the outside of the column 16. The side wall of the column 16 is equipped with a displacement sensor 15, and the bottom of the column 16 is equipped with a pressure sensor 112, a coal mine detection sensor 111, and a geological monitoring sensor 113.In this embodiment, the column 16 integrates a grouting pipe 12, a jetting pipe 13, and a suction pipe 14, enabling grouting, crushing, and back suction to be completed collaboratively within the same working hole. A grouting screen 121 is installed at the grouting end to improve grout diffusion and prevent impurity backflow; a suction filter 141 is installed at the suction end to intercept excessive particles and reduce the risk of blockage. A pressure sensor 112 is installed to monitor the jet and suction pressure, a displacement sensor 15 is installed to monitor the propulsion stroke, a coal mine detection sensor 111 is installed for coal body occurrence identification or coal quality characteristic identification, and a geological monitoring sensor 113 is installed for monitoring the surrounding rock condition. A tungsten carbide drill bit 114 is used to improve wear resistance and rock-breaking ability. The column 16 serves as a load-bearing shell, a hydraulic cylinder 17 is used for propulsion or extension adjustment, and a servo motor can be used for jet direction and device posture or local mechanism motion control to achieve point crushing and scanning crushing. This structure allows grouting sealing, high-pressure jet crushing, and negative pressure suction back suction to be implemented collaboratively within the same working channel, reducing the complexity of downhole layout and improving closed-loop control capabilities.

[0030] Example 3 like Figures 10-12 As shown, this embodiment provides an extreme environment mining method using in-situ jet crushing and negative pressure coal slurry backflow. Extreme environment legacy coal resources refer to legacy coal bodies located in old mining areas, goafs, abandoned roadways, or spaces where roadway layout is difficult, accompanied by risks such as water inrush, gas / harmful gas accumulation, and surrounding rock fracturing. The closed or semi-closed working boundary refers to the controllable working cavity boundary formed by grouting and surrounding rock stabilization, allowing negative pressure backflow to be established and maintained within a controllable range; this can be verified using negative pressure attenuation or leakage rate criteria.

[0031] The negative pressure back suction system 3 (vacuum load system) refers to the ground power and pipeline system that establishes a stable negative pressure field in the slurry suction pipeline 14 and drives the coal slurry to be lifted.

[0032] Coal slurry refers to a solid-containing multiphase medium formed by mixing crushed coal with a working medium, which can be in a gas-liquid-solid multiphase flow state. This method uses the in-situ jet crushing-negative pressure coal slurry back-suction extreme environment mining system from Example 1, and includes the following steps: S1. Complete the installation of the jet circulation system 5, negative pressure back suction system 3, grouting system 6, solid-liquid separation and reuse system and PLC intelligent control system 4 in the ground hole area. At the same time, complete the connection of the jet high pressure pipeline 36, grout suction pipeline 14, grouting pipeline 12 and sensor signal line, and perform self-test of sealing and interlocking functions. S2. Use borehole inspection, ground-penetrating radar, well logging or other detection methods to determine the spatial location, void morphology and risk zoning of the remaining coal body, then determine the number, diameter, orientation and depth of the working boreholes to ensure that the crushing device can cover the target coal body area, and finally plan the initial values ​​of grouting parameters and jet and negative pressure parameters, and formulate interlocking thresholds (pressure change, displacement over-limit, etc.); the borehole diameter range is preferably 133-216mm, explore the spatial morphology, coal body distribution and disaster factors of the old mine area and goaf, and construct a three-dimensional digital model; S3. Lower the crushing device to the designed position, start the grouting system 6 and perform annular sealing grouting through the grouting pipes 12 to form a seal between the orifice and the orifice section. Then, reinforce the boundary fissures of the void area, loose surrounding rock and weak roof area with grouting. If necessary, reinforce in sections and in stages to construct a controllable working cavity, provide sealed conditions for negative pressure back suction and improve the stability of the surrounding rock. The grouting pressure is 0.2-5 MPa, preferably 0.5-2 MPa. This forms a closed / semi-closed working boundary that meets the requirements of negative pressure back suction and jet crushing. The closed or semi-closed working boundary is: the target working area meets the negative pressure back suction conditions through grouting isolation. After the target negative pressure is established in the grouting pipe 14, the negative pressure decay does not exceed the preset threshold within a preset time or meets the preset leakage rate requirement through leakage detection. Preferably, the preset time is 5-30 min; the negative pressure decay threshold is 5-20 kPa; or the leakage rate does not exceed 0.5-5 kPa / min. The preferred grouting pressure is 0.5-2 MPa. Rapid grouting materials such as cement-based, cement-water glass, polyurethane, and composite quick-setting grouting materials are used, maintaining a water-cement ratio of 0.6-1.0 within the viscosity range to facilitate diffusion. After establishing the target negative pressure in the grout suction pipe 14, the negative pressure decay should not exceed a preset threshold within a preset time, or the leakage rate should not exceed a preset threshold. The sealing effect is verified by the negative pressure decay or leakage rate criteria: after establishing the target negative pressure in the grout suction pipe 14, the negative pressure decay should not exceed the threshold within a preset time. The single-hole coverage radius (effective jet distance) can reach 10m, the hole spacing is between 5-30m, and the directional drilling azimuth deviation is ≤1.0°. S4. Start the jet circulation system 5. The plunger pump 53 pressurizes the jet medium, which is then transported to the injection end through the high-pressure pipeline 36 and the jet pipeline 13. This performs targeted or trajectory-based jet erosion and crushing on the target coal body. The working medium is water or a solution containing additives, and the jet pressure is provided by the ultra-high-pressure plunger pump 53. The pressure range is preferably 20-300 MPa to adapt to different coal and rock properties. The nozzle diameter is 0.6-3.0 mm, the spray distance is 20-300 mm, and the flow rate is 10-120 L / min. This causes the coal body to be broken down into particles or fine particles and mixed with the medium. A coal slurry is formed. Based on feedback from the pressure sensor 112 and the coal mine detection sensor 111, the jet pressure, flow rate, injection angle and operating cycle are dynamically adjusted. The crushing efficiency is improved by switching the abrasive jet mode (abrasive particle size 0.2-1.0 mm, concentration 1-10%) for hard coal. In one embodiment, the preferred jet flow rate is 30-80 L / min, the nozzle diameter is 0.8-2.5 mm, the scanning speed / step is 0.01-0.3 m / s, the step is 5-50 mm, and the pulse jet frequency is 200 Hz.

[0033] S5. Start the vacuum load system. Vacuum pump 31 establishes a negative pressure zone in the suction pipe 14. The back-suction coal slurry is drawn into the suction pipe 14 through a filter screen and lifted from bottom to top under the action of negative pressure. The negative pressure at the suction inlet is -10 to -90 kPa. A suction filter screen 141 with a filter aperture of 5-30 mm is installed at the inlet of the suction pipe 14. The negative pressure back-suction system 3 maintains the negative pressure at the inlet of the suction pipe 14 at -10 to -90 kPa. The inner diameter of the suction pipe 14 is 50-200 mm, and the average flow velocity in the pipe is maintained at 1.5-3.5 m / s to suppress particle deposition. When the filter 33 or When the pressure difference ΔP across the pipeline is ≥20~80kPa, or the coal slurry flow rate decreases to a preset threshold, a de-clogging strategy is implemented, including backflushing, pulse suction, reverse flushing, or short-term pressure reduction. After de-clogging is completed, continuous back suction is resumed, and the delivery pump then stabilizes the back suction flow rate to maintain continuous output. By coordinating the jet flow rate Qj and the back suction flow rate Qs, the solid phase mass fraction of the coal slurry is kept at 10~40%, and the maximum particle size is kept below 10~30mm. When an abnormal pressure drop ΔP ≥20~80kPa or flow rate decrease is detected, backflushing and de-clogging strategies (such as short-term pressure reduction, pulse suction, reverse flushing, etc.) are implemented. S6. The back-suction coal slurry first passes through filter 33 for coarse filtration and impurity removal. The coal slurry then enters the inclined spiral solid-liquid separator 34 for continuous separation. The separated solid coal material enters the coal box 35 for recovery, and the separated liquid enters the water tank 52 and is reused in the jet circulation system 5 after sedimentation, filtration and purification, forming a closed-loop circulation, reducing water replenishment and discharge, with a reuse rate of ≥70%, preferably ≥80%. S7. Based on the evaluation of the coal mine detection sensor 111 and the operation effect, the PLC intelligent control system 4 instructs the mobile positioning system 2 to adjust the device position. By moving the slider 21, the sliding rail 22, and the servo motor driving the lead screw rail 24, point switching or trajectory scanning is achieved. Steps S3 to S6 are repeated to complete the zoning, layering, or block recovery. During the mining process, the jet pressure, negative pressure intensity, coal slurry flow rate, pressure difference ΔP, and surrounding rock stability parameters are monitored in real time by the sensors. The PLC intelligent control system 4 performs remote linkage parameter adjustment or triggers safety protection such as shutdown, pressure relief, blockage removal, and grouting reinforcement. S8. When the displacement sensor 15 and the geological monitoring sensor 113 detect abnormal displacement of the surrounding rock, the grouting reinforcement and load reduction shutdown are triggered. When the pressure sensor 112 detects that the jet or suction pressure exceeds the limit or changes abruptly, the shutdown, pressure relief and blockage removal are triggered. After the target area is recovered, the grouting, jet and negative pressure systems are stopped in sequence. If necessary, the hole is terminated or the grouting is reinforced to ensure long-term stability.

[0034] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An extreme environment mining method using in-situ jet crushing-negative pressure coal slurry back suction, characterized in that: include: Precise exploration and modeling were used to investigate the spatial morphology, coal distribution, and disaster factors of old mining areas and goaf areas, and to construct a three-dimensional digital model. The system is deployed and installed by setting up a jet circulation system, a negative pressure back suction system, a grouting system, a solid-liquid separation system and a PLC intelligent control system on the ground, and then installing an integrated drilling jet device through the working borehole to form a jet pipeline and a grout suction pipeline channel. For sealing and stabilizing, the grouting system is activated to seal and stabilize the cracks around the borehole and the target work area, forming a closed or semi-closed work boundary that meets the requirements of jet breaking and negative pressure back suction. In-situ jet crushing and slurry preparation involves pressurizing the working medium through a jet circulation system and then transporting it through a jet pipeline to an integrated drilling jet device in the well to form a jet. This jet then performs scanning or fixed-point impact, cutting, and crushing on the target coal body, mixing the crushed coal body with the working medium to form a coal slurry. The negative pressure coal slurry back suction and lifting system is activated to form a stable negative pressure field in the suction pipeline channel, so that the coal slurry enters the suction pipeline through suction filtration and is lifted to the ground collection end; Solid-liquid separation and closed-loop circulation: the ground collection end performs solid-liquid separation on the lifting coal slurry, recovers the coal, and the separated water is purified and reused in the jet circulation system to achieve closed-loop circulation of the working medium.

2. The extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction according to claim 1, characterized in that: In the sealing and stabilization step, the grouting sealing process includes segmented grouting reinforcement of the borehole annulus and the fracture zone of the goaf to suppress water inrush, suppress the flow of harmful gases and improve the stability of the surrounding rock. After the target negative pressure is established in the grouting pipeline, the negative pressure decay does not exceed the preset threshold within a preset time, or the leakage rate does not exceed the preset threshold.

3. The extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction according to claim 1, characterized in that: The jet is a continuous jet or a pulsed jet; the working medium is water or a solution containing additives.

4. The extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction according to claim 1, characterized in that: In the in-situ jet crushing and slurry preparation step, the slurry preparation process adjusts the jet flow rate and the back suction flow rate to maintain the coal slurry concentration within a range that can be stably transported, and forms a coal slurry collection zone at the bottom of the goaf or in a designated collection area.

5. The extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction according to claim 1, characterized in that: In the in-situ jet crushing and slurry preparation steps and the negative pressure coal slurry back suction lifting steps, the solid phase mass fraction of the coal slurry is maintained at 10-40% by coordinating the jet flow rate and the back suction flow rate, and the maximum particle size in the coal slurry does not exceed 10-30mm.

6. The extreme environment mining method of in-situ jet crushing-negative pressure coal slurry back suction according to claim 1, characterized in that: During the mining process, the jet pressure, negative pressure intensity, coal slurry flow rate, pressure difference, and surrounding rock stability parameters are monitored in real time by sensors. The PLC intelligent control system performs remote linkage parameter adjustment or triggers safety protection such as shutdown, pressure relief, blockage removal, and grouting reinforcement.

7. An extreme environment mining system for in-situ jet crushing-negative pressure coal slurry backflow mining method according to any one of claims 1 to 6, characterized in that: The system includes an integrated drilling jet device, a mobile positioning system, a negative pressure back suction system, a PLC intelligent control system, a jet circulation system, a grouting system, and a solid-liquid separation system. The jet circulation system, negative pressure back suction system, grouting system, solid-liquid separation system, PLC intelligent control system, and mobile positioning system are deployed on the ground in the proposed mining area. The integrated drilling jet device is mounted on the mobile end of the mobile positioning system to move it to a designated position and allow it to enter the proposed mining area through a borehole at that position. The grouting system, negative pressure back suction system, and jet circulation system are connected to the integrated drilling jet device via pipelines. One end of the solid-liquid separation system is connected to the end of the negative pressure back suction system furthest from the integrated drilling jet device, and the other end of the solid-liquid separation system is connected to the end of the jet circulation system furthest from the integrated drilling jet device via a liquid pipeline.

8. The extreme environment mining system of in-situ jet crushing-negative pressure coal slurry back suction according to claim 7, characterized in that: The integrated drilling jet device includes a drilling device, a grouting pipe, a jet pipeline, a grout suction pipeline, and a column. The top of the column is connected to the moving end of the mobile positioning system, and the drilling device is located at the bottom of the column. A hydraulic cylinder is installed inside the column, and a telescopic rod at the bottom of the hydraulic cylinder is connected to the drilling device. A third servo motor is installed inside the drilling device, and a drill bit is connected to the third servo motor. The drill bit passes through the bottom of the drilling device. A working hole is opened inside the column, and the lower opening of the working hole is located at the bottom of the drilling device. The grouting pipe, jetting pipe, and suction pipe are integrated within the working hole, with the bottom opening of the grouting pipe extending to the bottom of the drilling device and spaced apart from the drill bit. A grouting screen is provided at the bottom opening of the grouting pipe, and a suction filter is provided at the bottom opening of the suction pipe. The jetting pipe and suction pipe extend through the lower opening of the working hole to the outside of the column. A displacement sensor is provided on the side wall of the column, and a pressure sensor, a coal mine detection sensor, and a geological monitoring sensor are provided at the bottom of the column.

9. The extreme environment mining system of in-situ jet crushing-negative pressure coal slurry back suction according to claim 8, characterized in that: The mobile positioning system includes a horizontally arranged sliding rail on the ground, a sliding slider slidably connected to the sliding rail, and a second servo motor connected to the sliding slider. The second servo motor can drive the sliding slider to reciprocate along the length direction of the sliding rail. A horizontal track is fixedly connected to the sliding slider, and the horizontal track is perpendicular to the length direction of the sliding rail. A horizontal slider is provided on the horizontal track, and a driving device is connected to the horizontal slider to drive the horizontal slider to reciprocate along the horizontal track. A vertically arranged lead screw slide rail is provided on the horizontal slider, and a lead screw slider on the lead screw slide rail can move up and down along the lead screw slide rail. The lead screw slider is connected to the top of the column.

10. The extreme environment mining system of in-situ jet crushing-negative pressure coal slurry back suction according to claim 8, characterized in that: The negative pressure back suction system includes a vacuum pump, a first delivery pump, and a filter connected in sequence via a high-pressure pipeline. The inlet of the vacuum pump is connected to the slurry suction pipeline via a pipeline, and the outlet of the filter is connected to the solid-liquid separation system via a pipeline. The jet circulation system includes a water tank, the outlet of which is connected to the jet pipeline via a plunger pump, and the inlet of which is connected to the liquid outlet of the solid-liquid separation system via a second delivery pump. The grouting system includes a grouting machine, which is connected to the grouting pipe via a third delivery pump.

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