Coal spontaneous combustion and gas comprehensive treatment method for gob-side entry retaining of high-gas mine

Abstract

The invention discloses a high-gas mine gob-side entry retaining coal spontaneous combustion and gas comprehensive treatment method which comprises the following steps: arranging a windshield curtain on the side, close to a goaf, of a gob-side entry retaining, and injecting materials into a filling cavity through a filling grouting pipe to form a plugging layer; a closed air chamber is constructed on the side, close to the gob-side entry retaining, of the wind shielding curtain, nitrogen is injected into the gob, meanwhile, gas is safely extracted, and the oxygen concentration is reduced; through multi-stage prevention and control measures, the probability that the working face leaks air to the goaf through the gob-side entry retaining is reduced, the influence of leakage of poisonous and harmful gas in the goaf on mining of the adjacent working face is effectively avoided, harmful gas seepage is reduced, coal spontaneous combustion and gas of the gob-side entry retaining of the high-gas mine are comprehensively treated, and coal mine safety is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of coal spontaneous combustion prevention and control, and in particular to a method for comprehensive control of coal spontaneous combustion and gas along gob-retained lanes in high-gas mines. Background Art

[0002] Gob-side lane retention is a coal pillar-free mining technology. Specifically, the original return lane is maintained along the edge of the gob behind the coal mining face, and the drift of the previous section is re-supported by certain technical means, and then left for the next section. Gob-side lane retention can recycle the protective coal pillars left in the traditional mining method, maximize resource recovery, and avoid coal body loss. Gob-side lane retention has excellent effects such as improving the relationship between mining and excavation, increasing coal recovery rate, and reducing excavation workload.

[0003] In high-gas mines with gob-side lanes, coal and gas outbursts are prone to occur in gob areas. When coal spontaneous combustion occurs, the oxidation heat generation rate is greater than the heat dissipation rate to the environment, causing the coal body to accumulate heat continuously. The temperature of the coal body slowly and continuously rises until it reaches the ignition point of the coal and burns. Spontaneous combustion of coal can easily cause gas combustion and explosion, posing a great hidden danger to coal mine safety.

[0004] In the case where two working faces share one gob-side tunnel, the goaf area in the high-gas gob-side tunnel mine is exposed, and there are problems of gas leakage and spontaneous combustion of coal, which seriously endanger the safety of the coal mine. It is urgent to carry out comprehensive control of coal spontaneous combustion and gas. Summary of the invention

[0005] In order to comprehensively control the spontaneous combustion of coal and gas in gob-retained lanes in high-gas mines and ensure the safety of coal mines, the present application provides a method for comprehensively controlling the spontaneous combustion of coal and gas in gob-retained lanes in high-gas mines.

[0006] The present application provides a method for comprehensive control of spontaneous combustion of coal and gas in gob-retained lanes in high-gas mines, which adopts the following technical solutions:

[0007] A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lanes in high-gas mines, comprising the following steps:

[0008] S1; On the side of the goaf-retained roadway close to the goaf, a wind-blocking curtain is set up to prevent spontaneous combustion of coal in the goaf and the overflow of toxic and harmful gases. The wind-blocking curtain includes a pedestrian side isolation facility and a goaf side isolation facility, and a filling cavity is set between the pedestrian side isolation facility and the goaf side isolation facility;

[0009] S2: A filling grouting pipe is driven into the filling cavity from the gob-side tunnel. The height of the filling grouting pipe is located near the top of the wind-blocking curtain. The filling cavity is filled with materials in a sequential grouting manner to form a plugging layer. The injected material has good self-foaming performance, flow diffusion and stacking properties. At the same time, the injected material can achieve high-multiple expansion and rapid dense filling. The formed plugging layer has the characteristics of being non-flammable, non-combustible, and non-shrinking after solidification. The solidified foam body does not collapse or crack under a high-temperature fire source or in a high-temperature environment.

[0010] S3; Strengthen the re-injection according to the filling condition in the final filling cavity, so that the plugging layer fills the entire filling cavity;

[0011] S4; After the wind-blocking curtain and the sealing layer are solidified, shaped and compacted, a closed air chamber is constructed on the side of the wind-blocking curtain close to the gob-side entry, and the upper end of the closed air chamber is in contact with the roof, so that the gas in the gob area of ​​the high-gas mine leaks into the closed air chamber through cracks and boreholes, and a drainage port is set at the upper part of the closed air chamber;

[0012] S5; Use fire-proof drill bits, drill rods and pneumatic column drilling rigs along the goaf to arrange nitrogen injection holes in the goaf to inject nitrogen to prevent the remaining coal from igniting spontaneously.

[0013] Optionally, the pedestrian side isolation facilities include a plurality of double-layer diamond meshes, a first wind tube cloth and a plurality of first U-shaped steels, the first wind tube cloth is located between the double-layer diamond meshes and abuts against the double-layer diamond meshes, and all the first U-shaped steels abut against the side of the double-layer diamond meshes facing away from the goaf; the goaf side isolation facilities include a metal mesh, a second wind tube cloth and a plurality of second U-shaped steels, the first U-shaped steel and the second U-shaped steel are fixed to the top plate by anchor rods, the metal mesh abuts against the second U-shaped steel, and the second wind tube cloth abuts against the side of the metal mesh facing away from the goaf.

[0014] Optionally, the first U-shaped steel and the second U-shaped steel are both covered with shoelace caps, two adjacent first U-shaped steels are connected and fixed by a back plate, and adjacent second U-shaped steels are connected and fixed by a tie rod.

[0015] Optionally, between step S3 and step S4, a sealing material is sprayed on the top shoulder and bottom of the pedestrian side isolation facility close to the side of the tunnel left along the gondola.

[0016] Optionally, between step S3 and step S4, if deformation occurs in the goaf-retained tunnel, a hole is drilled in the goaf-retained tunnel, the hole passes through the wind-proof curtain and extends into the goaf, and then an isolation strip grouting pipe is used to pass through the hole and inject filling material into the goaf. The filling material is a highly water-retaining composite colloid material, and the injected filling material diffuses and fills the cracks within the strip and densely seals them to form a filled isolation zone; after the grouting is completed, the hole is sealed.

[0017] Optionally, a closed wall is provided in the goaf near another mining working face, and the closed wall is fixedly connected to the windproof curtain.

[0018] Optionally, a plurality of single supports are arranged in the gob-side tunnel retaining.

[0019] In summary, the present application includes at least one of the following beneficial technical effects:

[0020] 1. Set up a wind-blocking curtain on the side of the goaf-retained lane near the goaf, and fill the filling cavity of the wind-blocking curtain with material through the filling grouting pipe to form a blocking layer; then build a closed gas chamber on the side of the wind-blocking curtain near the goaf-retained lane, so that the gas in the goaf of the high-gas mine can enter the closed gas chamber through the cracks and drilling leakage points, and by arranging the extraction port, nitrogen is injected into the closed gas chamber while safely extracting gas to reduce the oxygen concentration; and by continuously injecting nitrogen into the goaf, the gas pressure in the goaf is controlled, and a positive pressure is formed on the leakage channel to effectively prevent air leakage; through multi-level prevention and control measures, the probability of air leakage from the working face to the goaf through the goaf-retained lane is reduced, and the leakage of toxic and harmful gases in the goaf is effectively avoided to affect the mining of the adjacent working face, and at the same time, the gangue falling from the goaf after the top cutting is prevented from pouring into the lane, and the spontaneous combustion of coal and gas in the goaf-retained lanes of high-gas mines are comprehensively controlled to ensure the safety of coal mines;

[0021] 2. Through nitrogen injection drilling, nitrogen is continuously injected into the goaf. On the one hand, it replaces the oxygen in the goaf and reduces the oxygen content to achieve gas inertization in the goaf. On the other hand, a positive pressure gas field is formed through nitrogen injection to further reduce air leakage from the working face to the goaf.

[0022] 3. The closed gas chamber can store harmful gases such as methane overflowing from the goaf. The gas sensors and temperature sensors are deployed to monitor the gas and temperature changes in real time. When the gas or temperature reaches the critical value, the methane in the closed gas chamber is promptly extracted and removed through the preset gas extraction port, and inert gas is pressed in to further reduce the seepage of toxic and harmful gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic plan view of the comprehensive control of spontaneous combustion of coal and gas in gob-side lane retention according to the present invention.

[0024] Figure 2 It is a schematic diagram of the arrangement of the U-shaped steel and the back plate on the pedestrian side of the windshield curtain of the present invention.

[0025] Figure 3 It is a schematic diagram of a first air duct cloth sandwiched between double-layer diamond-shaped nets of the present invention.

[0026] Figure 4 It is a schematic cross-sectional view of the windproof curtain of the present invention.

[0027] Figure 5It is a cross-sectional schematic diagram of the comprehensive control of spontaneous combustion of coal and gas in the gob-side lane retaining method of the present invention.

[0028] Explanation of the reference numerals in the accompanying drawings: 1. Enclosed air chamber; 2. Wind-proof curtain; 3. Filling isolation belt; 4. Nitrogen injection drilling; 5. Enclosed wall; 6. Gob-side tunnel; 7. First U-shaped steel; 8. Back plate; 9. First air duct cloth; 10. Diamond mesh; 11. Metal mesh; 12. Goaf; 13. Sealing layer; 14. Pedestrian side isolation facility; 15. Goaf side isolation facility; 16. Grouting pipe for isolation strip; 17. Single pillar; 18. Filling grouting pipe; 19. Extraction port; 20. Second air duct cloth; 21. Second U-shaped steel. DETAILED DESCRIPTION

[0029] The present application is further described in detail below in conjunction with all the accompanying drawings.

[0030] The embodiment of the present application discloses a method for comprehensive control of spontaneous combustion of coal and gas along gob-retained lanes in high-gas mines.

[0031] Example

[0032] Reference Figures 1 to 5 A method for comprehensive control of spontaneous combustion of coal and gas in gob-retained lanes in high-gas mines, comprising the following steps:

[0033] S1; The two working faces of the goaf-retained tunnel 6 share a tunnel, the lower working face is mined, and the goaf 12 is exposed. In order to ensure that the upper working face is less affected by the goaf 12 of the lower working face during the mining process, a windbreak curtain 2 is set on the side of the goaf-retained tunnel 6 close to the goaf 12 to prevent the spontaneous combustion of coal in the goaf 12 and the overflow of toxic and harmful gases. The windbreak curtain 2 includes a pedestrian side isolation facility 14 and a goaf side isolation facility 15. The goaf side isolation facility 15 is located on the side close to the goaf 12; a plurality of single supports 17 are set in the goaf-retained tunnel 6, and the single supports 17 support the top plate of the goaf-retained tunnel 6 to enhance the stability of the tunnel structure.

[0034] The pedestrian side isolation facility 14 includes a plurality of double-layer diamond meshes 10, a first air duct cloth 9 and a plurality of first U-shaped steels 7. The first air duct cloth 9 is located between the double-layer diamond meshes 10 and abuts against the double-layer diamond meshes 10. All first U-shaped steels 7 abut against the side of the double-layer diamond meshes 10 away from the goaf 12. Two adjacent first U-shaped steels 7 are connected and fixed by a back plate 8 (a steel pipe can be optionally used). The fixing method using the back plate 8 can effectively improve the connection strength and overall stability between the first U-shaped steels 7, prevent the spacing between the first U-shaped steels 7 from being too large, and thus ensure the fixing effect of the diamond mesh 10; the overlap of the diamond mesh 10 pieces is not less than 100mm, and the overlap is fixed with double strands of not less than No. 16 iron wire every 300mm, which further improves the rigidity and strength of the diamond mesh 10; the model of the first U-shaped steel 7 is selected according to the actual situation on site;

[0035] The isolation facility 15 on the goaf side includes a metal mesh 11, a second air duct cloth 20 and a plurality of second U-shaped steels 21. The first U-shaped steel 7 and the second U-shaped steel 21 are both covered with shoelace caps, which can increase the contact area between the first U-shaped steel 7 and the second U-shaped steel 21, and reduce the pressure on the first U-shaped steel 7 and the second U-shaped steel 21. The first U-shaped steel 7 and the second U-shaped steel 21 are fixed to the top plate by anchor rods to ensure effective resistance to the pressure of the side.

[0036] The metal mesh 11 is in contact with the second U-shaped steel 21, and the second air duct cloth 20 is in contact with the side of the metal mesh 11 facing away from the goaf 12. The adjacent second U-shaped steels 21 are connected and fixed by tie rods, which can effectively improve the connection strength and overall stability between the second U-shaped steels 21 and ensure the fixing effect of the diamond mesh 10; a filling cavity is provided between the second pedestrian side isolation facility 14 and the goaf side isolation facility 15.

[0037] S2; a filling grouting pipe 18 is driven into the filling cavity from the inside of the gob-side tunnel 6. The filling grouting pipe 18 is located near the top of the windshield curtain 2. A sequential grouting method is used to inject material into the filling cavity to form a blocking layer 13. The injected material has good self-foaming properties, flow diffusion and stacking properties. At the same time, the injected material can achieve high-multiple expansion and rapid dense filling (this embodiment uses the Pratt fire-fighting material JTF-Ⅱ produced by Xuzhou Ji'an Mining Technology Co., Ltd.); the formed blocking layer 13 has the characteristics of being non-flammable, non-combustible, and non-shrinking after curing, and the cured foam does not collapse or crack under a high-temperature fire source or in a high-temperature environment.

[0038] S3; according to the filling situation in the final filling cavity, the reinjection is strengthened so that the sealing layer 13 fills the entire filling cavity; a closed wall 5 is set near another mining face in the goaf 12, and the closed wall 5 is fixedly connected to the windshield curtain 2. The closed wall 5 further blocks the gas in the goaf 12 to prevent air leakage.

[0039] If the goaf-retained lane 6 is deformed, a hole is drilled in the goaf-retained lane 6, and the hole passes through the wind-proof curtain 2 and extends into the goaf 12. Then, the isolation strip grouting pipe 16 is used to pass through the hole and inject filling material into the goaf 12. The filling material uses a high water-retaining composite colloid material (the specific drilling height and the length of the isolation strip grouting pipe 16 extending into the goaf 12 can be adjusted according to the position of the oxidation zone in the goaf 12). The injected filling material diffuses and fills the cracks within the strip and densely seals them to form a filling isolation belt 3, which prevents coal spontaneous combustion in the entire strip, reduces oxidation, and lowers the temperature. After the grouting is completed, the hole is sealed. The filling isolation belt 3 serves as a second barrier to prevent the broken coal body on the roof of the lane from squeezing the wind-proof curtain 2, causing the broken coal body to collapse to the side of the goaf 12 to form a triangular coal area, thereby preventing coal spontaneous combustion caused by air leakage.

[0040] According to the pressure of the working face in the later stage, the filled area should be monitored more closely, and the positions with obvious air leakage should be replenished in time; the top shoulder and bottom positions of the pedestrian side isolation facility 14 close to the side of the reserved tunnel 6 should be sprayed with sealed sealing materials (such as polyurethane materials, which can enhance the sealing effect and prevent air leakage from the windshield curtain 2) to further improve the plugging effect of the windshield curtain 2.

[0041] S4; After the windbreak curtain 2 and the sealing layer 13 are solidified, shaped and compacted, a closed air chamber 1 is constructed on one side of the windbreak curtain 2 close to the goaf 6, and the upper end of the closed air chamber 1 is in contact with the roof, so that the gas in the goaf 12 of the high-gas mine leaks into the closed air chamber 1 through cracks and boreholes. At the same time, an extraction port 19 is set on the upper part of the closed air chamber 1. The closed air chamber 1 is provided with a gas sensor and a temperature sensor. The gas sensor monitors the gas concentration and content in the closed air chamber 1, and monitors the gas and temperature changes in real time. The temperature sensor monitors the temperature in the closed air chamber 1. When the gas or temperature reaches a critical value or exceeds the standard, the gas in the closed air chamber 1 is safely extracted and removed in time through the extraction port 19 to reduce the gas concentration and content, and nitrogen or other inert gases are injected to reduce the oxygen concentration and reduce the seepage of toxic and harmful gases.

[0042] S5; from the goaf-retained lane 6, a fire-proof drill bit, a drill rod and a pneumatic column drilling rig are used to arrange nitrogen injection holes 4 to inject nitrogen into the goaf 12 to prevent the spontaneous combustion of the residual coal; nitrogen is injected into the goaf 12, which, on the one hand, replaces the oxygen in the goaf 12 and reduces the oxygen content to achieve gas inertization in the goaf 12; on the other hand, the gas pressure in the goaf 12 is controlled by reasonably controlling the amount of nitrogen injection, forming a positive pressure gas field in the leakage channel, reducing air leakage from the working face to the goaf 12, and playing a role in preventing air leakage.

[0043] Through multi-level prevention and control measures, the probability of air leakage from the working face to the goaf 12 through the goaf-retained lane 6 is reduced, effectively avoiding the impact of toxic and harmful gas leakage in the goaf 12 on the mining of the adjacent working face. At the same time, it prevents the goaf 12 from falling gangue into the lane after top cutting, reduces the seepage of harmful gases, and comprehensively controls the spontaneous combustion of coal and gas in the goaf-retained lane 6 in high-gas mines to ensure the safety of coal mines.

[0044] The comprehensive method for controlling coal spontaneous combustion and gas of the present application has been put into practical application in Shanxi Heshun Zhengbang Coal Mine. There are spontaneous combustion of coal and high gas in goaf 12 of Shanxi Heshun Zhengbang Coal Mine along the goaf-retained lane 6. Through the control method of the present application, the safety of the working face from the pushing and mining to the withdrawal stage is guaranteed, and there is no suspension of mining or closure due to spontaneous combustion of coal and gas, and a good control effect is achieved.

[0045] The implementation principle of the method for spontaneous combustion of coal and comprehensive gas control along the goaf of a gas-rich mine in the embodiment of the present application is as follows: a windshield curtain 2 is set on the side of the goaf 6 near the goaf 12, and a filling grouting pipe 18 is used to fill the filling cavity of the windshield curtain 2 to form a blocking layer 13; a closed air chamber 1 is then constructed on the side of the windshield curtain 2 near the goaf 6, so that the gas in the goaf 12 of the gas-rich mine enters the closed air chamber 1 through cracks, boreholes and other leakage places, and the extraction port 19 is arranged to timely extract the overflowed gas to reduce the gas concentration and content, and nitrogen or other inert gases are injected to reduce the oxygen concentration and reduce toxic and harmful gases. seepage of the body; and by continuously injecting nitrogen into the goaf 12, the gas pressure in the goaf 12 is controlled, a positive pressure is formed on the air leakage channel, and air leakage is effectively prevented; through multi-level prevention and control measures, the probability of air leakage from the working face to the goaf 12 through the goaf-retained lane 6 is reduced, and the leakage of toxic and harmful gases in the goaf 12 is effectively avoided to affect the mining of the adjacent working face, and at the same time, the goaf 12 is prevented from falling and pouring into the lane after the top is cut; the closed gas chamber 1 stores the gas and other harmful gases overflowing from the goaf 12, which are extracted and removed in time to reduce the seepage of harmful gases, and the spontaneous combustion of coal and gas in the goaf-retained lane 6 of high-gas mines are comprehensively controlled to ensure the safety of coal mines.

[0046] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lanes in high-gas mines, characterized by: The following steps are involved: S1; a windshield curtain (2) is provided on the side of the goaf-retained tunnel (6) close to the goaf (12) to prevent spontaneous combustion of coal in the goaf (12) and the overflow of toxic and harmful gases; the windshield curtain (2) includes a pedestrian side isolation facility (14) and a goaf side isolation facility (15); a filling cavity is provided between the pedestrian side isolation facility (14) and the goaf side isolation facility (15); S2: driving a filling grouting pipe (18) from the gob-side tunnel into the filling cavity, the filling grouting pipe (18) being located close to the top of the windshield curtain (2), and using a sequential grouting method to inject material into the filling cavity to form a plugging layer (13), wherein the injected material has good self-foaming properties, flow diffusion properties and stacking properties, and the injected material can achieve high-multiple expansion and rapid dense filling; the formed plugging layer (13) has the characteristics of being non-flammable, non-combustible, and non-shrinking after solidification, and the solidified foam body does not collapse or crack under a high-temperature fire source or in a high-temperature environment; S3; strengthening the re-injection according to the filling condition in the final filling cavity, so that the plugging layer (13) fills the entire filling cavity; S4; after the windbreak curtain (2) and the sealing layer (13) are solidified, shaped and compacted, a closed air chamber (1) is constructed on the side of the windbreak curtain (2) close to the gob-side tunnel (6), the upper end of the closed air chamber (1) is in contact with the roof, so that the gas in the gob area (12) of the high-gas mine leaks into the closed air chamber (1) through cracks and drill holes, and at the same time, an extraction port (19) is set on the upper part of the closed air chamber (1); S5; from the gob-side tunnel (6), a fire-fighting drill bit and a drill rod are used in conjunction with a pneumatic column-type drill rig to arrange nitrogen injection holes (4) for nitrogen injection into the gob (6) to prevent the coal from spontaneously igniting.

2. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lanes in high-gas mines according to claim 1, characterized in that: The pedestrian side isolation facility (14) comprises a plurality of double-layer diamond meshes (10), a first air duct cloth (9) and a plurality of first U-shaped steels (7), wherein the first air duct cloth (9) is located between the double-layer diamond meshes (10) and abuts against the double-layer diamond meshes (10), and all the first U-shaped steels (7) abut against the side of the double-layer diamond meshes (10) facing away from the goaf (12); the goaf side isolation facility (15) comprises a metal mesh (11), a second air duct cloth (20) and a plurality of second U-shaped steels (21), wherein the first U-shaped steels (7) and the second U-shaped steels (21) are both fixed to the top plate by anchor rods, the metal mesh (11) abuts against the second U-shaped steels (21), and the second air duct cloth (20) abuts against the side of the metal mesh (11) facing away from the goaf (12).

3. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lanes in high-gas mines according to claim 2, characterized in that: The first U-shaped steel (7) and the second U-shaped steel (21) are both provided with shoelace caps, two adjacent first U-shaped steels (7) are connected and fixed by a back plate (8), and adjacent second U-shaped steels (21) are connected and fixed by a tie rod.

4. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lane retaining in high-gas mines according to claim 1, characterized in that: Between step S3 and step S4, a sealed plugging material is sprayed on the top shoulder and bottom of the pedestrian side isolation facility (14) close to the sideway tunnel (6).

5. The method for comprehensive control of spontaneous combustion of coal and gas in gob-side lane retaining in high-gas mines according to claim 1, characterized in that: Between step S3 and step S4, if deformation occurs in the gob-side tunnel (6), a hole is drilled in the gob-side tunnel (6), the hole passes through the wind-shielding curtain (2) and extends into the gob (12), and then a grouting pipe (16) of an isolation strip is used to pass through the hole and inject filling material into the gob (12). The filling material is a composite colloid material with high water retention. The injected filling material diffuses and fills the cracks within the strip range and densely seals them, forming a filled isolation strip (3); after the grouting is completed, the hole is sealed.

6. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lane retaining in high-gas mines according to claim 1, characterized in that: A closed wall (5) is arranged in the goaf area (12) near another mining working face, and the closed wall (5) is fixedly connected to the windproof curtain (2).

7. A method for comprehensive control of spontaneous combustion of coal and gas in gob-side lane retaining in high-gas mines according to claim 1, characterized in that: A plurality of single supports (17) are arranged in the gob-side tunnel retaining (6).

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