A rapid coal uncovering system and method based on simultaneous mining of coal and gas using physical fluidization

Abstract

The present invention discloses a rapid stone gate coal uncovering system and method based on physical fluidization co-mining of coal and gas. The rapid stone gate coal uncovering system includes a jet coal breaking unit, an orifice sealing unit, and a water-coal separation unit. The rapid stone gate coal uncovering method includes the steps of through-layer drilling, fluidized gas-coal co-mining, and grouting. The present invention utilizes a high-pressure sealed drill pipe and a jet device to generate a high-pressure water jet within the through-layer drill hole, in-situ cutting and crushing the coal body at the stone gate coal uncovering site. Furthermore, by designing fluidized coal mining drill holes arranged in an array around the roadway contour line at the stone gate coal uncovering site, all coal and gas near the stone gate are mined, rapidly releasing gas pressure in the outburst coal seam and reducing the probability of coal and gas outbursts during stone gate coal uncovering. The present invention can achieve safe and rapid stone gate coal uncovering, significantly shortening the stone gate coal uncovering period and ensuring the overall production progress of coal mining. The invention is particularly suitable for stone gate coal uncovering in high-gas mines.

Description

Technical Field

[0001] The present invention relates to a coal mining system and method for underground coal mining through stone gates, and in particular to a coal mining system and method for underground coal mining through stone gates, which are applicable to high gas outburst mines and are based on physical fluidization of coal and gas for rapid coal mining. The invention belongs to the field of coal mine safety technology. Background Art

[0002] In coal mining technology, a stone gate isn't a true gate. Instead, it refers to a rock tunnel excavated in a rock stratum that doesn't directly reach the surface and runs perpendicular or oblique to the coal seam. It primarily serves as a cross-layer tunnel connecting multiple layers of coal. Because the direction of tunneling through a stone gate passes through a coal seam, the process of uncovering a coal seam when encountering one during stone gate excavation is called stone gate coal uncovering.

[0003] Coal and gas outbursts are a special type of gas outburst, whereby crushed coal and gas, under pressure, suddenly erupt into the mining area. Coal and gas outbursts are extremely destructive and a major threat to coal mine safety. When a rock gate breaks through a coal seam, the danger of a coal and gas outburst is particularly high.

[0004] Currently, the typical method for coal mining through stone gates is to first extract gas from the coal seam, then proceed with tunneling and uncovering the coal seam after the pre-extraction gas reaches the specified level. To improve gas extraction efficiency, hydraulic punching, loosening blasting, and hydraulic slotting are often used to relieve pressure and increase permeability at the coal mine. While this traditional stone gate method has achieved some success, it has significant limitations. First, hydraulic punching, loosening blasting, and hydraulic slotting can damage the integrity of the coal body, altering the mining stress field and reducing coal strength in the uncovered area, thus maintaining the risk of coal and gas outbursts. Second, even with pressure-relief and permeability-increasing measures, gas extraction can still take a significant amount of time, particularly in mines with high gas outburst risk, where extraction can take over a year. For example, at a coal mine in southwest my country, gas extraction operations at the 18# coal section of the 114 stone gate uncovered at the site lasted for two years, severely impacting and restricting the overall production progress of the coal mine. Summary of the Invention

[0005] In response to the problems existing in the above-mentioned prior art, the present invention provides a stone gate rapid coal uncovering system and method based on the physical fluidization of coal and gas mining. It can realize the synchronous and safe mining of the coal seam at the coal uncovering location while shortening the time required for gas extraction, thereby realizing safe and rapid stone gate coal uncovering and ensuring the overall production progress of coal mining. It is particularly suitable for stone gate coal uncovering in high-gas outburst mines.

[0006] To achieve the above purpose, the stone gate rapid coal uncovering system based on physical fluidization mining of coal and gas includes a fluidization gas coal mining part, which includes a jet coal breaking unit, a hole sealing unit, and a water-coal separation unit;

[0007] The jet coal breaking unit includes a coal breaking drill bit, an injection device, a high-pressure sealed drill pipe, a high-pressure water tail, a drilling rig, and a high-pressure water pump. The high-pressure sealed drill pipe is a cylindrical structure with multiple sections of uniform outer diameter and sealed connections. The high-pressure sealed drill pipe has a hollow water-passing structure inside. The front end is sealed and connected to the injection device, and the rear end is sealed and connected to the high-pressure water tail. The coal breaking drill bit is installed at the front end of the injection device. The high-pressure water output end of the high-pressure water pump is sealed and connected to the high-pressure water tail through a pipeline. The drilling rig is connected to the high-pressure sealed drill pipe through a transmission connection.

[0008] The orifice sealing unit includes a front sealing sleeve, a sealing unit body and a rear sealing sleeve, which are coaxially butt-jointed and sealed in sequence. The high-pressure sealing drill pipe can pass through the orifice sealing unit along the front and rear axial directions of the orifice sealing unit, and a coal-water outflow channel is formed between the outer surface of the high-pressure sealing drill pipe and the inner surface of the front sealing sleeve. A supporting sealing ring that is sealed and matched with the outer diameter of the high-pressure sealing drill pipe is coaxially fixed in the rear sealing sleeve. The sealing unit body is a container structure with a large inner cavity. The top end of the sealing unit body is provided with a gas discharge outlet that passes through its inner cavity, and the gas discharge outlet can be installed in a sealed connection with a mine gas extraction pipe through a pipeline. The bottom end of the sealing unit body is provided with a water-coal discharge outlet that passes through its inner cavity, and the water-coal discharge outlet can be connected to a water-coal separation unit through a pipeline.

[0009] The water-coal separation unit includes a vibrating dewatering screen, a scraper conveyor and a sedimentation tank; the pipe outlet connecting the water-coal discharge outlet is arranged above the material input end of the vibrating dewatering screen, the material output end of the vibrating dewatering screen is arranged above the material input end of the scraper conveyor, and the pipe outlet connecting the dewatering output end of the vibrating dewatering screen is placed above the sedimentation tank.

[0010] As a further improvement of the present invention, the injection device is configured to have 1 to 8 jet nozzles, and the injection direction of the jet nozzle has an angle of 45° to 90° with the axial direction of the injection device, and multiple jet nozzles are evenly distributed along the circumferential direction of the injection device, and / or multiple jet nozzles are evenly distributed along the axial direction of the injection device.

[0011] As a further improvement of the present invention, the sedimentation tank can be designed as a multi-stage sedimentation structure, and the last-stage sedimentation tank is connected to the high-pressure water pump through a pipeline.

[0012] As a further improvement of the present invention, the supporting sealing rings are arranged in at least two groups along the axial direction of the rear sealing sleeve.

[0013] A method for rapid coal mining in a rock gate based on a rock gate rapid coal mining system with physical fluidization of coal and gas, the specific steps of which include through-layer drilling, fluidization gas-coal mining and grouting filling;

[0014] The construction steps of through-layer drilling are as follows: install a drilling rig at a distance of 7 to 10 meters from the coal seam at the stone gate excavation working face, install the coal-breaking drill bit at the front end of the high-pressure sealed drill pipe, install the high-pressure water tail at the rear end of the high-pressure sealed drill pipe, and connect the high-pressure water pump through a pipeline. Use the drilling rig to drive the coal-breaking drill bit to drill to a distance of 0.5 to 3 meters from the bottom plate of the coal seam, stop drilling, withdraw the high-pressure sealed drill pipe and the coal-breaking drill bit, replace the coal-breaking drill bit with a reaming drill bit, and reame the hole mouth position of the borehole. The reaming depth is 2 to 4 meters, and the inner diameter of the reaming hole is larger than the outer diameter of the front sealing casing; insert the front sealing casing at the reaming position, and install a sealing pipe between the borehole and the front sealing casing. Grouting is performed in the annulus between the two holes to fix the front sealing casing, and then the sealing unit body and the rear sealing casing are coaxially fixedly installed on the front sealing casing, and the gas outlet is sealed and connected to the mine gas extraction pipe through a pipeline, and the water-coal outlet is installed and connected to the water-coal separation unit through a pipeline; the reaming drill bit is replaced with a coal-breaking drill bit, and the high-pressure sealing drill rod and the coal-breaking drill bit are passed through the hole sealing unit. The high-pressure sealing drill rod and the coal-breaking drill bit are driven by the drilling rig to continue drilling from 0.5 to 3 meters away from the coal seam floor. The drilling is stopped when the drilling passes through 0.5 to 1 meter of the coal seam roof, and the high-pressure sealing drill rod and the coal-breaking drill bit are withdrawn;

[0015] The fluidized gas coal mining steps are as follows: the front end of the high-pressure sealed drill pipe is sequentially installed with an injection device and a coal-breaking drill bit, the high-pressure sealed drill pipe, the injection device and the coal-breaking drill bit are passed through the hole sealing unit, the coal-breaking drill bit and the injection device are extended to the bottom of the hole, the high-pressure water pump is started, and the high-pressure sealed drill pipe is controlled by the drilling rig to rotate at an appropriate speed to hydraulically break the coal, the broken coal body flows with the water through the annulus between the borehole and the high-pressure sealed drill pipe back to the inner cavity of the sealing unit body, and enters the water-coal separation unit through the water-coal discharge port, and the coal is broken. The gas released from the crushed coal body flows through the annulus between the borehole and the high-pressure sealing drill pipe to the inner cavity of the sealing unit body, and then enters the mine gas extraction pipe through the gas outlet. After the coal body around the borehole is mined, the high-pressure sealing drill pipe, injection device and coal-breaking drill bit are removed, and the sealing unit body and rear sealing casing are dismantled. The front sealing casing is then connected to the mine gas extraction pipe through a pipeline for continuous gas extraction. Then, the next designed borehole is drilled through the layer and the fluidized gas-coal mining operation is carried out.

[0016] The grouting filling steps are as follows: after the fluidized gas-coal mining operation of the last designed borehole is completed, the pipeline between the front sealing casing and the mine gas extraction pipe is removed, each borehole is sealed, and the entire coal mining cave is grouting-filled through the topmost front sealing casing; after the filling slurry is fully solidified, excavation operations can be carried out.

[0017] As a further improvement of the present invention, the through-layer drilling construction steps and the fluidized gas-coal mining steps are repeated, and multiple through-layer drilling holes are used to mine coal and gas within 12 to 15 meters around the tunnel outline at the stone gate coal uncovering site.

[0018] As a further improvement of the present invention, the drill holes are arranged in an array around the outline of the roadway at the stone gate coal uncovering location, and the center distance between the drill holes is coordinated with the effective hydraulic coal breaking range of the injection device.

[0019] As a further improvement scheme of the present invention, the coal mining method in the fluidized gas coal mining step adopts a step-back coal mining method: the high-pressure sealed drill rod is controlled to move forward and backward within a range of 1 to 2 meters until the coal output of the drill hole is greatly reduced, and all the coal within a range of 1 to 2 meters along the front and rear directions is crushed and mined, and then the high-pressure sealed drill rod is controlled to retreat 1 to 2 meters to the rear, and the above steps are repeated in a cycle to crush and mine all the coal within a range of 2 to 4 meters along the front and rear directions, and so on, and the "retreat-crushing coal-retreat-crushing coal" cycle is carried out until it approaches the bottom plate of the coal seam and all the coal around the drill hole is mined.

[0020] Compared with existing technologies, when using this rapid stone gate coal uncovering system and method based on the physical fluidization of coal and gas for stone gate coal uncovering, all coal and gas near the stone gate can be quickly mined, quickly reducing the gas pressure and gas content of the coal seam, completing regional anti-burst measures for stone gate coal uncovering in a short period of time, and greatly shortening the stone gate coal uncovering period; moreover, the mined coal and gas can be efficiently separated to achieve resource recycling; in addition, tunnel excavation is carried out in a coal-free filling body, ensuring the inherent safety of stone gate coal uncovering. This method has simple equipment, easy operation, and reliable control, and realizes safe and rapid stone gate coal uncovering operations in high-gas mines, ensuring the overall production progress of coal mining, and has significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the present invention when fluidized gas and coal are mined simultaneously;

[0022] Figure 2 This is a schematic diagram of the equipment layout of the present invention located in the Shimen lane;

[0023] Figure 3 This is a schematic diagram of the installation structure of the high-pressure sealing drill pipe and the orifice sealing unit for fluidized gas-coal simultaneous mining according to the present invention;

[0024] Figure 4 It is a schematic structural diagram of the injection device of the present invention;

[0025] Figure 5 The present invention is a drilling design layout diagram for mining within a range of 12 to 15 meters around the outline of the roadway at the stone gate coal uncovering area.

[0026] In the figure: 1. Jet coal breaking unit; 1-1. Coal breaking drill bit; 1-2. Injection device; 1-2-1. Jet nozzle; 1-3. High-pressure sealed drill pipe; 1-4. High-pressure water tail; 1-5. Drilling rig; 1-6. High-pressure water pump; 2. Orifice sealing unit; 2-1. Front sealing casing; 2-2. Sealing unit body; 2-2-1. Gas discharge outlet; 2-2-2. Water-coal discharge outlet; 2-3. Rear sealing casing; 2-3-1. Support sealing ring; 3. Water-coal separation unit; 3-1. Vibrating dewatering screen; 3-2. Scraper conveyor; 3-3. Sedimentation tank; 4. Mine gas extraction pipe. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings (the following description will be made with the drilling direction of the high-pressure sealed drill rod 1-3 as the front).

[0028] A stone gate rapid coal uncovering system based on physical fluidization mining of coal and gas includes a fluidization gas coal mining part, which includes a jet coal breaking unit 1, a hole sealing unit 2, and a water-coal separation unit 3;

[0029] like Figure 1 、 Figure 2 As shown, the jet coal breaking unit 1 includes a coal breaking drill bit 1-1, an injection device 1-2, a high-pressure sealed drill pipe 1-3, a high-pressure water tail 1-4, a drilling rig 1-5 and a high-pressure water pump 1-6; the high-pressure sealed drill pipe 1-3 is a multi-section, sealed cylindrical connection structure with the same outer diameter, and a hollow water flow structure is provided inside the high-pressure sealed drill pipe 1-3. The front end is sealed and connected to the injection device 1-2, and the rear end is sealed and connected to the high-pressure water tail 1-4; the coal breaking drill bit 1-1 is installed at the front end of the injection device 1-2; the high-pressure water output end of the high-pressure water pump 1-6 is sealed and connected to the high-pressure water tail 1-4 through a pipeline; the drilling rig 1-5 is connected to the high-pressure sealed drill pipe 1-3 by transmission;

[0030] like Figure 3As shown, the orifice sealing unit 2 includes a front sealing sleeve 2-1, a sealing unit main body 2-2 and a rear sealing sleeve 2-3 which are coaxially butt-jointed and sealed in sequence. The high-pressure sealing drill pipe 1-3 can pass through the orifice sealing unit 2 along the front and rear axial directions of the gas mining device 2, and a coal-water outflow channel is formed between the outer surface of the high-pressure sealing drill pipe 1-3 and the inner surface of the front sealing sleeve 2-1. A supporting sealing ring 2-3-1 which is coaxially fixed in the rear sealing sleeve 2-3 and seals with the outer diameter size of the high-pressure sealing drill pipe 1-3 is coaxially fixed. The sealing unit main body 2-2 is a container structure with a large inner cavity. The top end of the sealing unit main body 2-2 is provided with a gas discharge outlet 2-2-1 which passes through its inner cavity, and the gas discharge outlet 2-2-1 can be installed in a sealed connection with the mine gas extraction pipe 4 through a pipeline. The bottom end of the sealing unit main body 2-2 is provided with a water-coal discharge outlet 2-2-2 which passes through its inner cavity, and the water-coal discharge outlet 2-2-2 can be connected to the water-coal separation unit through a pipeline.

[0031] The water-coal separation unit 3 includes a vibrating dewatering screen 3-1, a scraper conveyor 3-2, and a sedimentation tank 3-3. The outlet of the pipeline connecting to the water-coal discharge port 2-2-2 is located above the material input end of the vibrating dewatering screen 3-1. The material output end of the vibrating dewatering screen 3-1 is located above the material input end of the scraper conveyor 3-2. The outlet of the pipeline connecting to the dewatering output end of the vibrating dewatering screen 3-1 is located above the sedimentation tank 3-3. To achieve water resource reuse, the sedimentation tank 3-3 can be designed as a multi-stage sedimentation structure. The final stage of the sedimentation tank is connected to the high-pressure water pump 1-6 via a pipeline to achieve water resource reuse.

[0032] The rapid coal uncovering method of Shimen specifically comprises the following steps:

[0033] The construction steps of through-layer drilling are as follows: install the drilling rig 1-5 at a distance of 7 to 10 m from the coal seam at the stone gate excavation working face, install the coal-breaking drill bit 1-1 at the front end of the high-pressure sealed drill pipe 1-3, install the high-pressure water tail 1-4 at the rear end of the high-pressure sealed drill pipe 1-3, and connect the high-pressure water pump 1-6 through a pipeline; use the drilling rig 1-5 to drive the coal-breaking drill bit 1-1 to drill to a distance of 0.5 to 3 m from the coal seam bottom plate and stop drilling (the coal seam bottom plate is the layer of the coal seam close to the stone gate); withdraw the high-pressure sealed drill pipe 1-3 and the coal-breaking drill bit 1-1, replace the coal-breaking drill bit 1-1 with a reaming drill bit, and reame the borehole mouth position with a reaming depth of 2 to 4 m, and the reaming inner diameter is larger than the outer diameter of the front sealing casing 2-1; lower the front sealing casing 2-1 at the reaming position, and carry out Grouting is performed to fix the front sealing casing 2-1, and then the sealing unit body 2-2 and the rear sealing casing 2-3 are coaxially fixedly installed on the front sealing casing 2-1, and the gas outlet 2-2-1 is installed in a sealed connection with the mine gas extraction pipe 4 through a pipeline, and the water-coal outlet 2-2-2 is installed and connected with the water-coal separation unit 3 through a pipeline; after the reaming drill bit is replaced with a coal-breaking drill bit 1-1, and the high-pressure sealing drill rod 1-3 and the coal-breaking drill bit 1-1 are passed through the hole sealing unit 2, the drilling rig 1-5 is used to drive the high-pressure sealing drill rod 1-3 and the coal-breaking drill bit 1-1 to continue drilling forward from 0.5 to 3 meters away from the bottom plate of the coal seam, and the drilling is stopped when it passes through the top plate of the coal seam 0.5 to 1 meter (the top plate of the coal seam is the layer of the coal seam away from the stone gate), and the high-pressure sealing drill rod 1-3 and the coal-breaking drill bit 1-1 are withdrawn to complete the through-layer drilling.

[0034] The fluidized gas coal mining steps are as follows: the front end of the high-pressure sealed drill pipe 1-3 is sequentially installed with the injection device 1-2 and the coal-breaking drill bit 1-1, and the high-pressure sealed drill pipe 1-3, the injection device 1-2 and the coal-breaking drill bit 1-1 are passed through the hole sealing unit 2, so that the coal-breaking drill bit 1-1 and the injection device 1-2 are extended to the bottom of the hole; the high-pressure water pump 1-6 is started, and the high-pressure sealed drill pipe 1-3 is controlled to rotate at an appropriate speed through the drilling rig 1-5, and high-pressure water is ejected from the injection device 1-2 through the high-pressure sealed drill pipe 1-3, impacting and crushing the coal body in the borehole, and the crushed coal body flows with the water through the annulus between the borehole and the high-pressure sealed drill pipe 1-3 and flows back to the inner cavity of the sealing unit body 2-2, and enters the water-coal separation unit through the water-coal discharge port 2-2-2 for subsequent treatment, and the gas released from the crushed coal body is discharged in the mine gas extraction. Under the action of the extraction negative pressure in the pipe 4, the coal flows through the annulus between the borehole and the high-pressure sealed drill rod 1-3 to the inner cavity of the sealing unit body 2-2, and enters the mine gas extraction pipe 4 through the gas outlet 2-2-1, thereby realizing the simultaneous mining of coal and gas; the coal mining method can adopt a step-back coal mining method, that is, the high-pressure sealed drill rod 1-3 is controlled to move back and forth within a range of 1 to 2 meters until the coal output of the borehole is greatly reduced, and finally all the coal within a range of 1 to 2 meters in the front and rear direction is crushed and mined, and then the high-pressure sealed drill rod 103 is controlled to retreat 1 to 2 meters to the rear, and the above steps are repeated in a cycle, and finally all the coal within a range of 2 to 4 meters in the front and rear direction is crushed and mined, and so on, the retreat-coal breaking-retreat-coal breaking cycle works until it approaches the coal seam bottom plate position and all the coal around the borehole is mined.

[0035] The grouting filling steps are as follows: after the fluidized gas-coal mining operation of the last designed borehole is completed, the pipeline between the front sealing casing 2-1 and the mine gas extraction pipe 4 is removed, each borehole is sealed, and the entire coal mining cave is grouting-filled through the top front sealing casing 2-1; after the filling slurry is fully solidified, the tunnel excavation operation can be carried out.

[0036] In order to mine out all the coal and gas within the safe range of the roadway contour line at the stone gate coal uncovering, as a further improvement scheme of the present invention, Figure 5 As shown, according to the drilling design layout diagram, the through-layer drilling construction steps and the fluidized gas-coal mining steps are repeated to mine the coal and gas within 12 to 15 meters around the tunnel contour line at the stone gate coal uncovering site.

[0037] In order to fully exploit the coal body within 12 to 15 m around the outline of the roadway at the stone gate, as a further improvement of the present invention, Figure 5 As shown, multiple coal mining drill holes are required, and the drill holes are arranged in an array around the outline of the roadway at the stone gate coal uncovering area, and the center distance between the drill holes is coordinated with the effective hydraulic coal breaking range of the injection device 1-2.

[0038] In order to achieve better water cutting effect, as a further improvement of the present invention, Figure 4 As shown, the injection device 1-2 is configured to have 1 to 8 jet nozzles 1-2-1, and the injection direction of the jet nozzle 1-2-1 has an angle of 45° to 90° with the axial direction of the injection device 1-2, and multiple jet nozzles 1-2-1 are evenly distributed along the circumferential direction of the injection device 1-2, and / or multiple jet nozzles 1-2-1 are evenly distributed along the axial direction of the injection device 1-2.

[0039] When using this rapid stone gate coal uncovering system based on the physical fluidization of coal and gas, all coal and gas near the stone gate can be quickly mined, rapidly reducing the gas pressure and gas content of the coal seam. Regional coal burst prevention measures for stone gate coal uncovering can be completed in a short period of time, greatly shortening the stone gate coal uncovering period. Furthermore, the mined coal and gas can be efficiently separated, enabling resource recycling. Furthermore, tunnel excavation is carried out within a coal-free backfill, ensuring the inherent safety of stone gate coal uncovering. This method features simple equipment, easy operation, and reliable control, enabling safe and rapid stone gate coal uncovering operations in high-gas mines, ensuring the overall production progress of coal mining, and achieving significant economic benefits.

Claims

1. A rapid coal mining system based on physical fluidization of coal and gas, characterized by: The fluidized gas-coal mining part includes a jet coal breaking unit (1), an orifice sealing unit (2), and a water-coal separation unit (3); The jet coal breaking unit (1) comprises a coal breaking drill bit (1-1), an injection device (1-2), a high-pressure sealed drill pipe (1-3), a high-pressure water tail (1-4), a drilling rig (1-5) and a high-pressure water pump (1-6); the high-pressure sealed drill pipe (1-3) is a cylindrical structure with multiple sections of uniform outer diameter and sealed installation connection, with a hollow water passage provided inside, the front end of which is sealed and connected to the injection device (1-2), and the rear end of which is sealed and connected to the high-pressure water tail (1-4); the coal breaking drill bit (1-1) is installed at the front end of the injection device (1-2); the high-pressure water output end of the high-pressure water pump (1-6) is sealed and connected to the high-pressure water tail (1-4) through a pipeline; the drilling rig (1-5) is connected to the high-pressure sealed drill pipe (1-3) in a transmission manner; The orifice sealing unit (2) comprises a front sealing sleeve (2-1), a sealing unit body (2-2), and a rear sealing sleeve (2-3) which are coaxially butt-jointed and sealed in sequence; a high-pressure sealing drill pipe (1-3) can pass through the orifice sealing unit (2) along the axial direction of the orifice sealing unit (2), and a coal-water outflow channel is formed between the outer surface of the high-pressure sealing drill pipe (1-3) and the inner surface of the front sealing sleeve (2-1); a sealing element which is coaxially fixed in the rear sealing sleeve (2-3) and which is in sealing conformity with the outer diameter of the high-pressure sealing drill pipe (1-3) is provided. A supporting sealing ring (2-3-1); the sealing unit body (2-2) is a container structure with a large inner cavity; the top of the sealing unit body (2-2) is provided with a gas discharge outlet (2-2-1) penetrating the inner cavity thereof, and the gas discharge outlet (2-2-1) can be installed in a sealed communication with a mine gas extraction pipe (4) through a pipeline; the bottom of the sealing unit body (2-2) is provided with a water-coal discharge outlet (2-2-2) penetrating the inner cavity thereof, and the water-coal discharge outlet (2-2-2) is connected to the water-coal separation unit (3) through a pipeline; The water-coal separation unit (3) comprises a vibrating dewatering screen (3-1), a scraper conveyor (3-2) and a sedimentation tank (3-3); the outlet of a pipeline connected to a water-coal discharge port (2-2-2) is arranged above the material input end of the vibrating dewatering screen (3-1), the material output end of the vibrating dewatering screen (3-1) is arranged above the material input end of the scraper conveyor (3-2), and the outlet of a pipeline connected to the dewatering output end of the vibrating dewatering screen (3-1) is placed above the sedimentation tank (3-3). The sedimentation tank (3-3) is a multi-stage sedimentation structure, and the last-stage sedimentation tank is connected to a high-pressure water pump (1-6) through a pipeline.

2. The rapid coal uncovering system based on physical fluidization of coal and gas mining according to claim 1 is characterized in that: The injection device (1-2) is provided with 1 to 8 jet nozzles (1-2-1), and the injection direction of the jet nozzle (1-2-1) forms an angle of 45° to 90° with the axial direction of the injection device (1-2). The plurality of jet nozzles (1-2-1) are evenly distributed along the circumferential direction of the injection device (1-2), and / or the plurality of jet nozzles (1-2-1) are evenly distributed along the axial direction of the injection device (1-2).

3. The rapid coal uncovering system based on physical fluidization of coal and gas mining according to claim 1 is characterized in that: The supporting sealing rings (2-3-1) are arranged in at least two groups along the axial direction of the rear sealing sleeve (2-3).

4. A method for rapid coal uncovering in a rock gate based on the rapid coal uncovering system based on the physical fluidization of coal and gas mining according to claim 1, characterized in that: The specific steps include through-layer drilling construction, fluidized gas-coal mining and grouting filling; The through-layer drilling construction steps are as follows: a drilling rig (1-5) is installed at a distance of 7 to 10 m from the coal seam at the stone gate excavation working face, a coal-breaking drill bit (1-1) is installed at the front end of the high-pressure sealed drill pipe (1-3), a high-pressure water tail (1-4) is installed at the rear end of the high-pressure sealed drill pipe (1-3), and a high-pressure water pump (1-6) is connected through a pipeline; the drilling rig (1-5) is used to drive the coal-breaking drill bit (1-1) to drill to a distance of 0.5 to 3 m from the bottom plate of the coal seam, and the drilling is stopped, the high-pressure sealed drill pipe (1-3) and the coal-breaking drill bit (1-1) are withdrawn, and the coal-breaking drill bit (1-1) is replaced with a reaming drill bit to reame the hole mouth position of the borehole, the reaming depth is 2 to 4 m, and the reaming inner diameter is larger than the outer diameter of the front sealing casing (2-1); the front sealing casing (2-1) is lowered into the reaming position, and the annulus between the borehole and the front sealing casing (2-1) is drilled. Grouting is performed to fix the front sealing sleeve (2-1), and then the sealing unit body (2-2) and the rear sealing sleeve (2-3) are coaxially fixedly installed on the front sealing sleeve (2-1), and the gas outlet (2-2-1) is sealed and connected to the mine gas extraction pipe (4) through a pipeline, and the water-coal outlet (2-2-2) is installed and connected to the water-coal separation unit (3) through a pipeline; after the hole expansion drill bit is replaced with a coal breaking drill bit (1-1), and the high-pressure sealing drill rod (1-3) and the coal breaking drill bit (1-1) are passed through the hole sealing unit (2), the high-pressure sealing drill rod (1-3) and the coal breaking drill bit (1-1) are driven by the drilling rig (1-5) to continue drilling forward from 0.5 to 3 meters away from the coal seam bottom plate, and the drilling is stopped when the drilling passes through 0.5 to 1 meter of the coal seam top plate, and the high-pressure sealing drill rod (1-3) and the coal breaking drill bit (1-1) are withdrawn; The fluidized gas-coal mining process comprises the following steps: a jet device (1-2) and a coal-breaking drill bit (1-1) are sequentially installed at the front end of a high-pressure sealed drill pipe (1-3); the high-pressure sealed drill pipe (1-3), the jet device (1-2) and the coal-breaking drill bit (1-1) are passed through a hole sealing unit (2) so that the coal-breaking drill bit (1-1) and the jet device (1-2) are extended to the bottom of the hole; a high-pressure water pump (1-6) is started, and the high-pressure sealed drill pipe (1-3) is controlled to rotate at an appropriate speed through a drilling rig (1-5) to hydraulically break the coal; the broken coal body flows back along with the water through the annulus between the borehole and the high-pressure sealed drill pipe (1-3) to the inner cavity of the sealing unit body (2-2), and is discharged through a water-coal discharge port (2-2-2). After entering the water-coal separation unit (3), the gas released by the crushed coal body flows through the annulus between the borehole and the high-pressure sealing drill rod (1-3) to the inner cavity of the sealing unit body (2-2), and enters the mine gas extraction pipe (4) through the gas outlet (2-2-1); after completing the mining of the coal body around the borehole, the high-pressure sealing drill rod (1-3), the injection device (1-2) and the coal-breaking drill bit (1-1) are withdrawn, and the sealing unit body (2-2) and the rear sealing casing (2-3) are removed, and then the front sealing casing (2-1) is connected to the mine gas extraction pipe (4) through a pipeline for sealing and installation, and continuous gas extraction is carried out; then the next designed borehole is drilled through the layer and the fluidized gas-coal mining operation is carried out; The grouting filling steps are as follows: after the fluidized gas-coal mining operation of the last designed borehole is completed, the pipeline between the front sealing casing (2-1) and the mine gas extraction pipe (4) is removed, each borehole is sealed, and the entire coal mining cave is grout-filled through the top front sealing casing (2-1); after the filling slurry is fully solidified, the tunnel excavation operation is carried out.

5. The method for rapid coal uncovering in a rock gate based on physical fluidization of coal and gas mining according to claim 4 is characterized in that: Repeat the through-layer drilling construction steps and fluidized gas-coal mining steps, and use multiple through-layer drilling holes to mine coal and gas within 12 to 15 meters around the tunnel outline at the stone gate coal uncovering site.

6. The method for rapid coal uncovering in a rock gate based on physical fluidization of coal and gas mining according to claim 5, characterized in that: The drill holes are arranged in an array around the outline of the roadway at the stone gate coal uncovering location, and the center distance between the drill holes is coordinated with the effective hydraulic coal breaking range of the injection device (1-2).

7. The method for rapid coal uncovering in a rock gate based on physical fluidization of coal and gas mining according to claim 4, characterized in that: In the fluidized gas coal mining step, a step-back mining method is adopted: the high-pressure sealed drill rod (1-3) is controlled to move forward and backward within a range of 1 to 2 meters until the coal output of the drill hole is greatly reduced, and all the coal within a range of 1 to 2 meters in the front and rear directions is crushed and mined. Then, the high-pressure sealed drill rod (1-3) is controlled to retreat 1 to 2 meters backward, and the fluidized gas coal mining step is continuously repeated to crush and mine all the coal within a range of 2 to 4 meters in the front and rear directions. Similarly, the "retreat-coal crushing-retreat-coal crushing" cycle is carried out until the position close to the coal seam bottom is approached and all the coal around the drill hole is mined.

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