A working face short hole static pressure water injection combined spray dust fall system and use method

Abstract

A working face shallow hole static pressure water injection combined spray dust fall system and a use method thereof, comprising a spray system and a shallow hole static pressure water injection dust fall system. The spray system is arranged at upper and lower corner angles and is composed of a spray head, a water supply hose and a backwashing filter device. The shallow hole static pressure water injection dust fall system is composed of a static pressure water tank, a cooling water pipe, a water injection water supply hose, a hole water injection valve, a total water supply valve, an original extraction pipe, a cylindrical filter screen, a lifting support, a scrap borehole, a water guide pipe, a first cooling water recovery tank and a second cooling water recovery tank. The spray system can wet the residual coal in the upper and lower corner angle goaf and can filter and remove impurities of mine water, thereby preventing the spray head from being blocked due to water quality during use. The shallow hole static pressure water injection dust fall system injects cooling waste water into the coal seam by using the original gas extraction pipeline, thereby reducing dust generation during coal cutting. The system has a simple structure, realizes secondary use of cooling water, and improves the whole working face dust fall effect.

Description

Technical Field

[0001] This invention relates to a dust suppression system for working faces and its application method, particularly applicable to a shallow-hole static pressure water injection combined with spray dust suppression system and its application method in high-gas mines or gas outburst mines with coal seam extraction pipelines. Background Technology

[0002] Coal dust is one of the five major natural disasters in coal mines and has always been a key focus of prevention and control efforts in the coal industry. The unique properties of coal dust determine its significant hazards: on the one hand, dust-polluted working environments severely harm workers' health, causing lung diseases and pneumoconiosis. Workers exposed to coal dust for extended periods are prone to pneumoconiosis. On the other hand, excessively high dust concentrations pose a potential explosion risk; suspended coal dust is also a major cause of coal dust explosions. Furthermore, the coal dust in our mine is explosive. Simultaneously, clean water supply in coal mines is difficult, pipeline laying is costly, and the coal mining machines, scraper conveyors, hydraulic supports, belt conveyors, and transfer machines used are water-cooled. Cooling water discharged into the working face causes water accumulation, affecting normal production and transportation. Therefore, to improve the working environment at the working face, reduce dust concentration at the working face and in the two roadways, and create conditions for the recycling and reuse of cooling water at the working face, a shallow-hole static pressure water injection combined with spray dust suppression system and its application method have been invented. This system is of great significance for safe production at the mining face. Summary of the Invention

[0003] Technical Problem: The purpose of this invention is to address the problems existing in the prior art by providing a working face shallow hole static pressure water injection combined with spray dust suppression system and its usage method that is simple in structure, safe and efficient, can effectively avoid nozzle clogging, and improve the moisture content of coal.

[0004] Technical Solution: The present invention provides a shallow-hole static pressure water injection combined spray dust suppression system for working faces, comprising a spray system and a shallow-hole static pressure water injection dust suppression system; the spray system is located at the ends of the return air roadway and the transport roadway, and includes a spray head, a spray water outlet hose, a backwash filter device, a spray water inlet valve, and a spray water inlet pipe, with each device connected in sequence; the shallow-hole static pressure water injection dust suppression system includes a static pressure water tank, a cooling water pipe, a water injection supply hose, the original extraction pipe, a lifting support frame, a water pump, a first cooling water recovery tank, and a second cooling water recovery tank; the static pressure water tank is located at the tail end of the return air roadway and is mounted on the lifting support frame, and is connected to the original extraction pipe via the water injection supply hose, and the second cooling water recovery tank is connected to the first cooling water recovery tank via a cold zone water pipe, and the first cooling water recovery tank is pumped into the static pressure water tank via the water pump through the cooling water pipe.

[0005] Preferably, the backwashing filtration device includes a housing, a diverting valve, a cylindrical filter screen, a drain baffle, a drain pipe, and a drain valve; the cylindrical filter screen and the housing are on the same axis, and the housing located in the middle of the cylindrical filter screen is provided with a diverting valve that can block the flow of water inside the cylindrical filter screen; the rear end of the cylindrical filter screen is connected to the spray inlet pipe, the front end of the cylindrical filter screen is provided with a drain baffle, and a drain pipe leading to the outside of the housing is provided on the cylindrical filter screen near the drain baffle, and a drain valve is provided on the drain pipe; an inlet pressure gauge is provided at the spray inlet pipe of the housing, and an outlet pressure gauge is provided at the outlet.

[0006] Preferably, the lower part of the static pressure water tank is provided with a filter screen bag that is higher than the main water supply valve.

[0007] Preferably, the height difference between the water level in the static pressure tank and the highest point of the borehole is greater than or equal to 0.

[0008] Preferably, the distance between the original extraction pipe and the working face is less than 10m.

[0009] Preferably, the diameter of the water injection hose is 5-10 mm smaller than the diameter of the original extraction pipe.

[0010] Preferably, each branch outlet of the original extraction pipe is equipped with a branch injection valve to control the water inlet of each branch.

[0011] The method of using the above-mentioned shallow-hole static pressure water injection combined with spray dust suppression system for working faces includes the following steps:

[0012] S1. On-site installation

[0013] A spray system and a shallow-hole static pressure water injection dust reduction system are arranged in the mining face. The spray system is located at the upper and lower corners of the transport roadway and the return air roadway. The static pressure water tank of the shallow-hole static pressure water injection dust reduction system is located at the end of the return air roadway. The outlet of the static pressure water tank is connected to the original extraction pipe through a water supply hose. A first cooling water recovery tank is set at the rear of the return air roadway on the side of the coal mining machine, and a second cooling water recovery tank is set at the rear of the transport roadway on the side of the coal mining machine. The second cooling water recovery tank is connected to the first cooling water recovery tank through a cold zone water pipe. The first cooling water recovery tank is connected to the top of the static pressure water tank through a cooling water pipe.

[0014] S2. Spray system in operation.

[0015] Open the spray inlet valve on the spray inlet pipe. Simultaneously, open the diverting valve as the working water flows into the housing. The water flows through the cylindrical filter screen and enters the housing. The filtered water inside the housing is then delivered to the spray head via the spray outlet hose. During the filtration process, dirt and impurities gradually accumulate on the inner front side of the cylindrical filter screen, forming a filter impurity layer. At this point, a pressure difference is created between the inner and outer sides of the cylindrical filter screen. When the pressure difference exceeds 0.5 MPa, close the diverting valve, blocking the middle of the cylindrical filter screen. Then, open the drain valve, allowing water to flow from the outside to the inside of the cylindrical filter screen, rinsing and draining the filter screen to ensure water quality. When the pressure difference approaches zero, the draining is complete. Open the diverting valve and close the drain valve to repeat the spray dust suppression process.

[0016] S3 shallow-hole static pressure water injection dust reduction system in operation

[0017] S31: Cooling water is recovered from the coal mining machine, hydraulic support, scraper conveyor, transfer machine and belt conveyor in the transport roadway, which are located in the working face cuttings. The cooling water generated in the working face is recovered to the second cooling water recovery tank, and then transported to the first cooling water recovery tank through the cold zone water pipe. The cooling water in the first cooling water recovery tank is pumped to the static pressure water tank through the cooling water pipe and filtered through the filter screen.

[0018] S32: Static pressure water injection. The height of the static pressure water tank and the opening size of the main water supply valve are adjusted by lifting the support frame. The number of branch holes, the total amount of water injected at one time, and the flow rate of water injected at one time are controlled according to different working face conditions. This controls the gas release rate accumulated in the original extraction pipe branch, ensuring that no gas abnormalities occur during water injection, and ensuring that the water injection flow rate can meet the working face advancement speed.

[0019] S4. Working Face Mining

[0020] S41: Before each shift of mining, cooling wastewater is used to inject water into the coal seam. The water supply hose connected to the static pressure water tank is connected to the original extraction pipe less than 10m ahead of the working face. Cooling water recovered from the static pressure water tank is sent into the coal seam through the original extraction pipe for static pressure water injection. When water appears on the coal wall around the branch hole of the original extraction pipe and on the coal wall of the working face, it proves that the coal seam within the water injection control range has been moistened. Water injection is stopped or the water injection volume is reduced and recorded. Then the working face is mined.

[0021] S42: As the working face advances, the static pressure water injection dust reduction system and the spray dust reduction system are moved accordingly along the direction of the working face advance. The water supply hose of the static pressure water injection dust reduction system is connected to the branch pipe of the original extraction pipe at a distance of less than 10m from the next advanced working face to carry out the next cycle of water injection.

[0022] Preferably, the single water injection flow rate in S32 is calculated based on the working face conditions. First, the number of branches connected to the shallow hole static pressure water injection dust reduction system is determined by the unit advance of the working face and the branch spacing of the original extraction pipe. Then, the single water injection volume is calculated by combining the product of the coal wetting system near the branch, the coal thickness, the branch spacing, the borehole length, the coal density, and the water injection volume per ton of coal. Finally, the single water injection time is determined according to the working face advance speed to obtain the single water injection flow rate.

[0023] Formula for calculating the number of support holes in a single shallow-hole static pressure water injection dust reduction system:

[0024]

[0025] Where: N is the number of branch holes connected to the shallow hole static pressure water injection dust reduction system in a single operation; D is the unit advance of the working face in meters; d is the spacing between branch holes in meters.

[0026] Formula for calculating single injection volume:

[0027] Q=k×M×d×l×ρ×δ×N (2)

[0028] In the formula: Q is the single injection volume, m 3 k is the wetting coefficient of the coal seam in front of the injection hole; M is the coal seam thickness, m; d is the spacing between the support holes, m; l is the borehole length, m; ρ is the density of the coal, t / m³. 3 δ represents the water injection volume per ton of coal (in m³). 3 / t;

[0029] Formula for calculating single injection flow rate:

[0030]

[0031] In the formula: Q is the single injection volume, m 3 q represents the single injection flow rate in meters. 3 / h; T is the water injection time, in hours.

[0032] Beneficial Effects: By addressing the aforementioned technical issues, this invention utilizes cooling wastewater for coal seam water injection and employs a backwashing filter to filter the cooling water, effectively preventing nozzle clogging and ensuring the treated cooling water meets spraying standards. This effectively controls dust concentration at the working face and improves the working environment. Since the working face motor is a high-power device, motor overheating poses a safety hazard. While the cooling water system cools the equipment, much of the already heated motor cooling water flows into the coal leakage hole or is discharged into the drainage ditch, resulting in significant water waste. Utilizing cooling wastewater for coal seam water injection not only solves the cooling water discharge problem but also achieves reuse, saving costs. Continuous spraying at the lower corner effectively moistens residual coal, reducing the natural oxidation rate of the coal body. It also moistens residual coal in the goaf to a certain extent, lowers air temperature, and utilizes the wetting properties of water to seal some cracks, reducing air leakage in the goaf. The shallow-hole static pressure water injection dust reduction system enables the secondary use of cooling water at the tail of the working face, pre-wetting the coal face and making full use of abandoned extraction boreholes, achieving "multi-purpose use of one borehole." This avoids the discharge of cooling water and increases the moisture content of the coal, thereby reducing coal dust generation to a certain extent. The entire device has a simple structure, is easy to use, safe, efficient, and requires low investment. It has wide applicability in this technical field and can also serve as a reference for other mining projects. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the system layout of the present invention.

[0034] Figure 2 This is a schematic diagram of the spray system structure of the present invention.

[0035] Figure 3 This is a schematic diagram of the shallow-hole static pressure water injection dust reduction system of the present invention.

[0036] In the diagram: 1-Spray water inlet pipe, 2-Spray water inlet valve, 3-Backwash filter device, 4-Spray water outlet hose, 5-Spray head, 6-Collapsed coal, 7-Return airway, 8-Transport roadway, 9-Working face cut, 10-Original extraction pipe, 11-Diverter water injection valve, 12-Cooling water pipe, 13-Water pump, 14-First cooling water recovery tank, 15-Second cooling water recovery tank, 16-Coal mining machine, 17- 18-Hydraulic support, 19-Scraper conveyor, 20-Transfer conveyor, 21-Belt conveyor, 22-Main water supply valve, 23-Water supply hose, 24-Lifting rack, 25-Filter screen bag, 26-Static pressure tank, 27-Shell, 28-Inlet pressure gauge, 29-Outlet pressure gauge, 30-Diverter valve, 31-Cylindrical filter screen, 32-Drainage baffle, 33-Drainage pipe, 34-Drainage valve, 35-Support hole. Detailed Implementation

[0037] An embodiment of the present invention will be further described below with reference to the accompanying drawings:

[0038] The present invention provides a working face shallow hole static pressure water injection combined spray dust suppression system, which mainly consists of a spray system and a shallow hole static pressure water injection dust suppression system; the spray system is located at the end of the return air roadway (7) and the transport roadway (8), and the original extraction pipe (8) is less than 10m ahead of the working face. The spray system includes a spray head (5), a spray water outlet hose (4), a backwash filter device (3), a spray water inlet valve (2), and a spray water inlet pipe (1), and the devices are connected in sequence. The shallow hole static pressure water injection dust reduction system includes a static pressure water tank (25), a cooling water pipe (12), a water injection supply hose (22), an original extraction pipe (10), a lifting support frame (23), a water pump (13), a first cooling water recovery tank (14), and a second cooling water recovery tank (15). The static pressure water tank (25) is located at the end of the return air duct (7), and the static pressure water tank (25) is installed on the lifting support frame (23). The static pressure water tank (25) is connected to the original extraction pipe (8) through the water injection supply hose (22). The diameter of the water injection supply hose (22) is 5-10 mm smaller than the diameter of the original extraction pipe (8). Each branch outlet of the original extraction pipe (8) is equipped with a branch water injection valve (11) to control the water inlet of each branch. The second cooling water recovery tank (15) is connected to the first cooling water recovery tank (27) via a cold zone water pipe (12). The first cooling water recovery tank (27) is pumped into the static pressure tank (25) via a water pump (13) through a cooling water pipe (12). The water level in the static pressure tank (25) is greater than or equal to the height difference between the highest point of the borehole and the water level in the static pressure tank (25). A filter screen (24) higher than the main water supply valve (21) is provided in the lower part of the static pressure tank (25).

[0039] The backwashing filter device (3) includes a housing (26), a diverting valve (29), a cylindrical filter screen (30), a drain baffle (31), a drain pipe (32), a drain valve (33), and a cylindrical filter screen (30) and a housing (26) on the same axis. The housing (26) located in the middle of the cylindrical filter screen (30) is provided with a diverting valve (29) that can block the flow of water inside the cylindrical filter screen. The rear end of the cylindrical filter screen (30) is connected to the spray inlet pipe (1). The front end of the cylindrical filter screen (30) is provided with a drain baffle (31). The cylindrical filter screen (30) near the drain baffle (31) is provided with a drain pipe (32) leading to the outside of the housing (26). The drain pipe (32) is provided with a drain valve (33). The spray inlet pipe (1) of the housing (26) is provided with an inlet pressure gauge (14), and the outlet is provided with an outlet pressure gauge (15).

[0040] The specific steps for using the shallow-hole static pressure water injection combined with spray dust suppression system of the present invention are as follows:

[0041] S1. On-site installation

[0042] A spray system and a shallow-hole static pressure water injection dust reduction system are arranged in the mining face. The spray system is located at the upper and lower corners of the transport roadway (8) and the return air roadway (7). The static pressure water tank (25) of the shallow-hole static pressure water injection dust reduction system is located at the end of the passage of the return air roadway (7). The outlet of the static pressure water tank (25) is connected to the original extraction pipe (8) through the water injection supply hose (22). A first cooling water recovery tank (27) is set at the rear of the return air roadway (7) on the side of the coal mining machine (16). A second cooling water recovery tank (15) is set at the rear of the transport roadway (8) on the side of the coal mining machine (16). The second cooling water recovery tank (15) is connected to the first cooling water recovery tank (27) through the cold zone water pipe (12). The first cooling water recovery tank (27) is connected to the top of the static pressure water tank (25) through the cooling water pipe (12).

[0043] S2. Spray system in operation.

[0044] Open the spray inlet valve (2) on the spray inlet pipe (1). At the same time as the working water flows into the housing (26), open the diverting valve (29). The water flows into the housing (26) after being filtered by the cylindrical filter screen (30). The filtered water in the housing (26) is transported to the spray head (5) by the spray outlet hose (4) and sprayed out. During the water filtration process, dirt and impurities in the water gradually accumulate on the inner front end of the cylindrical filter screen (30) to form a filter impurity layer. At this time, a pressure difference is formed between the inner and outer sides of the cylindrical filter screen (30). When the pressure difference is greater than 0.5MPa, close the diverting valve (29). The middle of the cylindrical filter screen (30) is blocked. At this time, open the drain valve (33). The water flows from the outside of the cylindrical filter screen (30) to the inside to rinse and drain the cylindrical filter screen (30) to ensure the water supply quality. When the pressure difference is close to 0, the drain is completed. Open the diverting valve (29) and close the drain valve (33) to repeat the spray dust suppression.

[0045] S3 shallow-hole static pressure water injection dust reduction system in operation

[0046] S31: Cooling water is recycled. The cooling water generated by the coal mining machine (16), hydraulic support (17), scraper conveyor (18) arranged in the working face cut (9) and the transfer machine (19) and belt conveyor (20) in the transport roadway (8) is recycled to the second cooling water recycling tank (15), and then transported to the first cooling water recycling tank (27) through the cold zone water pipe (12). The cooling water in the first cooling water recycling tank (27) is pumped to the static pressure water tank (25) through the cooling water pipe (12) and the water pump (13), and filtered through the filter screen (24).

[0047] S32: Static pressure water injection, the height of the static pressure water tank (25) and the opening size of the main water supply valve (22) are adjusted by lifting the support frame (23), and the number of branch holes (34) of the original extraction pipe (10) connected to the shallow hole static pressure water injection dust reduction system, the total amount of water injected at one time and the flow rate of water injected at one time are controlled according to different working face conditions, thereby controlling the gas release rate accumulated in the original extraction pipe (10) branch, ensuring that no gas abnormality occurs during water injection, and ensuring that the water injection flow rate can meet the working face advancement speed;

[0048] S4. Working Face Mining

[0049] S41: Before mining each working face, cooling wastewater is used to inject water into the coal seam. The water supply hose (22) connected to the static pressure water tank (25) is connected to the original extraction pipe (8) which is less than 10m ahead of the working face. The cooling water recovered in the static pressure water tank (25) is sent into the coal seam for static pressure water injection through the original extraction pipe (8). When water appears in the coal wall around the branch hole (34) of the original extraction pipe (8) and the coal wall of the working face, it proves that the coal seam within the water injection control range has been moistened. Stop water injection or reduce the amount of water injection and make a record. Then the working face is mined.

[0050] S42: As the working face advances, the static pressure water injection dust reduction system and the spray dust reduction system are moved accordingly along the working face advancement direction. The water injection supply hose (22) of the static pressure water injection dust reduction system is connected to the branch hole (34) of the original extraction pipe (10) less than 10m away from the next advanced working face to carry out the next cycle of water injection work.

[0051] The single water injection flow rate in S32 is calculated based on the working face conditions. First, the number of branch holes (34) for single access to the shallow hole static pressure water injection dust reduction system is determined by the unit advance of the working face and the spacing of the branch holes (34) of the original extraction pipe (10), as shown in formula (1). Then, the single water injection volume is calculated by combining the product of the coal wetting system near the branch hole (34), the coal thickness, the branch hole spacing, the borehole length, the coal density, and the water injection volume per ton of coal, as shown in formula (2). Then, the single water injection time is determined according to the working face advance speed, and the single water injection flow rate is obtained, as shown in formula (3).

[0052] Formula for calculating the number of branch holes (34) in a single shallow-hole static pressure water injection dust reduction system:

[0053]

[0054] Where: N is the number of branch holes connected to the shallow hole static pressure water injection dust reduction system in a single operation; D is the unit advance of the working face in meters; d is the spacing between branch holes in meters.

[0055] Formula for calculating single injection volume:

[0056] Q=k×M×d×l×ρ×δ×N (2)

[0057] In the formula: Q is the single injection volume, m 3 k is the coal wetting coefficient in front of the injection hole; d is the spacing between the support holes, in meters; l is the borehole length, in meters; ρ is the density of the coal, in t / m³. 3 δ represents the water injection volume per ton of coal (in m³). 3 / t;

[0058] Formula for calculating single injection flow rate:

[0059]

[0060] In the formula: Q is the single injection volume, m 3 q represents the single injection flow rate in meters. 3 / h; T is the water injection time, in hours.

[0061] The working face adopted in-seam drilling pre-extraction gas prevention measures in the coal seam gas area of ​​the mining area. Multiple sets of boreholes were drilled along the dip direction from the return airway and transport roadway, and the remaining ones became the original drainage pipes; the original drainage pipes were used for water injection. As the working face advanced, other subsequent boreholes were used.

Claims

1. A shallow-hole static pressure water injection combined spray dust suppression system for working faces, comprising a spray system and a shallow-hole static pressure water injection dust suppression system; the spray system comprises a spray head (5), a spray water outlet hose (4), a backwash filter device (3), a spray water inlet valve (2), and a spray water inlet pipe (1) connected in sequence; the shallow-hole static pressure water injection dust suppression system comprises a static pressure water tank (25), a cooling water pipe (12), a water injection supply hose (22), a primary extraction pipe (10), a lifting support frame (23), a water pump (13), a first cooling water recovery tank (14), and a second cooling water recovery tank (15); characterized in that: The spray system is located at the ends of the return air chute (7) and the transport chute (8). The static pressure water tank (25) is located at the tail end of the return air chute (7). The static pressure water tank (25) is mounted on the lifting support frame (23). The static pressure water tank (25) is connected to the original extraction pipe (10) through the water injection supply hose (22). The second cooling water recovery tank (15) is connected to the first cooling water recovery tank (14) through the cooling water pipe (12). The first cooling water recovery tank (14) is pumped into the static pressure water tank (25) through the cooling water pipe (12) via the water pump (13). The lower part of the static pressure water tank (25) is equipped with a filter screen bag (24) higher than the main water supply valve (21). The backwashing filter device (3) includes a housing (26), a diverting valve (29), a cylindrical filter screen (30), a drain baffle (31), a drain pipe (32), and a drain valve (33). The cylindrical filter screen (30) and the housing (26) are on the same axis. The housing (26) located in the middle of the cylindrical filter screen (30) is provided with a diverting valve (29) that can block the flow of water inside the cylindrical filter screen. The rear end of the cylindrical filter screen (30) is connected to the spray inlet pipe (1). The front end of the cylindrical filter screen (30) is provided with a drain baffle (31). The cylindrical filter screen (30) near the drain baffle (31) is provided with a drain pipe (32) leading to the outside of the housing (26). The drain pipe (32) is provided with a drain valve (33). The spray inlet pipe (1) of the housing (26) is provided with an inlet pressure gauge (27), and the outlet is provided with an outlet pressure gauge (28).

2. The shallow-hole static pressure water injection combined with spray dust suppression system for working faces according to claim 1, characterized in that: The height difference between the water level in the static pressure tank (25) and the highest position of the borehole is greater than or equal to 0.

3. The shallow-hole static pressure water injection combined with spray dust suppression system for working faces according to claim 1, characterized in that: The distance between the original extraction pipe (10) and the working face is less than 10m.

4. The shallow-hole static pressure water injection combined with spray dust suppression system for working faces according to claim 1, characterized in that: The diameter of the water injection hose (22) is 5-10 mm smaller than that of the original extraction pipe (10).

5. The shallow-hole static pressure water injection combined with spray dust suppression system for working faces according to claim 1, characterized in that: Each branch outlet of the original extraction pipe (10) is equipped with a branch injection valve (11) to control the water inlet of each branch.

6. The method of using the shallow-hole static pressure water injection combined with spray dust suppression system for working faces according to any one of claims 1-5, characterized in that... Includes the following steps: S1. On-site installation A spray system and a shallow-hole static pressure water injection dust reduction system are arranged in the mining face. The spray system is located at the upper and lower corners of the transport roadway (8) and the return air roadway (7). The static pressure water tank (25) of the shallow-hole static pressure water injection dust reduction system is located at the end of the passage of the return air roadway (7). The outlet of the static pressure water tank (25) is connected to the original extraction pipe (10) through the water injection supply hose (22). A first cooling water recovery tank (14) is set at the rear of the return air roadway (7) on the side of the coal mining machine (16). A second cooling water recovery tank (15) is set at the rear of the transport roadway (8) on the side of the coal mining machine (16). The second cooling water recovery tank (15) is connected to the first cooling water recovery tank (14) through the cooling water pipe (12). The first cooling water recovery tank (14) is connected to the top of the static pressure water tank (25) through the cooling water pipe (12). S2. Spray system in operation. Open the spray inlet valve (2) on the spray inlet pipe (1). At the same time as the working water flows into the housing (26), open the diverting valve (29). The water flows into the housing (26) after being filtered by the cylindrical filter screen (30). The filtered water in the housing (26) is transported to the spray head (5) by the spray outlet hose (4) and sprayed out. During the water filtration process, dirt and impurities in the water gradually accumulate on the inner front end of the cylindrical filter screen (30) to form a filter impurity layer. At this time, a pressure difference is formed between the inner and outer sides of the cylindrical filter screen (30). When the pressure difference is greater than 0.5MPa, close the diverting valve (29). The middle of the cylindrical filter screen (30) is blocked. Open the drain valve (33). The water flows from the outside of the cylindrical filter screen (30) to the inside to flush and drain the cylindrical filter screen (30) and ensure the water supply quality. When the pressure difference is close to 0, the sewage discharge is completed. Open the diversion valve (29) and close the sewage discharge valve (33) to repeat the spray dust suppression. S3 shallow-hole static pressure water injection dust reduction system in operation S31: Recycle cooling water. The cooling water generated by the coal mining machine (16), hydraulic support (17), scraper conveyor (18) arranged in the working face cut (9) and the transfer machine (19) and belt conveyor (20) in the transport roadway (8) is recycled to the second cooling water recycling tank (15), and then transported to the first cooling water recycling tank (14) through the cooling water pipe (12). The cooling water in the first cooling water recycling tank (14) is pumped to the static pressure water tank (25) through the cooling water pipe (12) and pumped by the water pump (13), and filtered by the filter screen (24). S32: Static pressure water injection, the height of the static pressure water tank (25) and the opening size of the main water supply valve (21) are adjusted by lifting the support frame (23), and the number of branch holes (34) of the original extraction pipe (10) connected to the shallow hole static pressure water injection dust reduction system, the total amount of water injected at one time and the flow rate of water injected at one time are controlled according to different working face conditions, thereby controlling the gas release rate accumulated in the branch holes of the original extraction pipe (10), ensuring that no gas abnormality occurs during water injection, and ensuring that the water injection flow rate can meet the speed of working face advancement; S4. Working Face Mining S41: Before mining each working face, cooling wastewater is used to inject water into the coal seam. The water supply hose (22) connected to the static pressure water tank (25) is connected to the original extraction pipe (10) which is less than 10m ahead of the working face. The cooling water recovered in the static pressure water tank (25) is sent into the coal seam for static pressure water injection through the original extraction pipe (10). When water appears on the coal wall around the branch hole (34) of the original extraction pipe (10) and the coal wall of the working face, it proves that the coal seam within the water injection control range has been moistened. Stop water injection or reduce the amount of water injection and make a record. Then the working face is mined. S42: As the working face advances, the static pressure water injection dust reduction system and the spray dust reduction system are moved accordingly along the direction of the working face advance. The water injection supply hose (22) of the static pressure water injection dust reduction system is connected to the branch hole (34) of the original extraction pipe (10) less than 10m away from the next advanced working face to carry out the next cycle of water injection work. The single water injection flow rate in step S32 is calculated based on the working face conditions. First, the number of branch holes (34) connected to the shallow hole static pressure water injection dust reduction system is determined by the unit advance of the working face and the spacing of the branch holes (34) of the original extraction pipe (10). Then, the single water injection volume is calculated by combining the product of the coal wetting system near the branch holes (34), the coal thickness, the branch hole spacing, the borehole length, the coal density, and the water injection volume per ton of coal. Finally, the single water injection time is determined according to the working face advance speed to obtain the single water injection flow rate. Formula for calculating the number of branch holes (34) in a single shallow-hole static pressure water injection dust reduction system: In the formula: N is the number of branch holes connected to the shallow hole static pressure water injection dust reduction system in a single operation; D is the unit advance of the working face in meters; d is the spacing between branch holes in meters. Formula for calculating single injection volume: Q=k×M×d×l×ρ×δ×N (2) In the formula: Q is the single injection volume, m 3 k is the wetting coefficient of the coal seam in front of the injection hole; M is the coal seam thickness, m; d is the spacing between the support holes, m; l is the borehole length, m; ρ is the density of the coal, t / m³. 3 δ represents the water injection volume per ton of coal (in m³). 3 / t; Formula for calculating single injection flow rate: In the formula: Q is the single injection volume, m 3 q represents the single injection flow rate in meters. 3 / h; T is the water injection time, in hours.

Images