Gob-side entry retaining working face gas disaster comprehensive prevention and control method

Abstract

The invention discloses a comprehensive prevention and control method for gob-side entry retaining working face gas disasters, and belongs to the technical field of mine gas disaster prevention and control. A local fan is installed in an air inlet main roadway, the local fan supplies air to a belt crossheading and an air inlet crossheading of a next adjacent working face through an air duct, an adjusting air door is installed on a rail crossheading, air is supplied to the working face in a W-shaped local pressurization mode, and the stope air pressure is adjusted by adjusting and controlling parameters of the local fan and the adjusting air door. The method comprises the following steps: arranging directional blast holes in a track gate road, forming a crack parallel to the gob-side entry retaining through directional shaped charge blasting, transforming the blast holes into gas extraction holes after top cutting is completed, carrying out gob-side entry retaining top plate gas extraction, cutting a bottom plate and burying a gas extraction pipe before a gob-side entry retaining stope face is stoped, and carrying out gas extraction on the gob-side entry retaining top plate; and after the gas extraction pipe enters the goaf, gas in the bottom plate is extracted. According to the method, the gas emission amount of the working face is greatly reduced, and effective prevention and control of the gob-side entry retaining gas are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of mine gas disaster prevention and control, and specifically is a comprehensive prevention and control method for gas disasters in a gob-side lane retaining working face. Background Art

[0002] With the increase in coal mining depth and mining intensity, the mining site structure is becoming more and more complex, and the characteristics of "three highs and one low" (high gas content, high gas pressure, high ground stress, and low permeability) are becoming more and more obvious. The deep coal mining process will be accompanied by more complex gas dynamic disasters, which can easily lead to serious and major accidents.

[0003] When mining coal seam groups, the technology of coal pillar-free mining along the goaf of the protective layer is an effective means of preventing outbursts in the mine area. Goaf-retaining mining can reduce the impact of stress concentration caused by the coal pillars on the decompression range of the protected layer, improve the decompression effect of the protective layer, and reduce the excavation workload and the amount of coal pillars left in the outburst coal seam. In addition, with the depletion of coal resources, more and more mines are in urgent need of promoting the technology of coal pillar-free mining along the goaf, so as to reduce the large amount of coal loss caused by the protective coal pillars. However, this technology has huge safety hazards when used in mines with complex conditions, which are manifested as: the goaf-retaining roadway is easy to deform and difficult to support, the goaf area has serious air leakage, large gas outburst volume, and serious natural ignition of Y-type ventilation. Among them, gas can be three-dimensionally gushed out from the side, roof, and floor of the goaf, with a large outburst volume. The gas in the goaf-retaining roadway is easy to exceed the limit, and gas disaster prevention and control is difficult.

[0004] Therefore, it is urgent to control the gas in the tunnels along the goaf. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of serious deformation of goaf-retained lanes, large three-dimensional gas outburst and easy spontaneous combustion of coal caused by Y-type ventilation during the current coal pillar-free mining along the goaf-retained lanes in high-gas mines, and to provide a comprehensive prevention and control method for gas disasters in the working face along the goaf-retained lanes.

[0006] The present invention is achieved through the following technical solutions: A comprehensive method for preventing and controlling gas disasters in a gob-side tunnel-retaining working face comprises the following steps: S1: Using the coal pillar-free mining technology with gob-side entry retention, two adjacent working faces are excavated, namely the gob-side entry retention mining working face and the next adjacent mining working face.

[0007] S2: After the gob-side entry mining working face is formed, an adjustable air door is installed at the head of the track drift.

[0008] S3: Install local fans in the main air intake tunnel.

[0009] S4: The local fan outlet supplies air to the belt chute and the next adjacent working surface air inlet chute through the wind duct.

[0010] S5: By adjusting the size of the local fan and the damper in the track chute, the air volume and pressure in the mining area are controlled to realize the air supply in the "W-shaped local pressurization" mode along the gob-retaining lane. Among them, a "W-shaped local pressurization" ventilation mode is formed between the track chute, the belt chute and the air inlet chute of the next adjacent working face.

[0011] S6: Install U-shaped differential pressure gauges on both sides of the regulating damper, and monitor the internal airflow pressure of the mining face along the goaf-retaining lane by reading the U-shaped differential pressure gauges.

[0012] S7: Gas concentration sensors are arranged at the intersection of the gob-side entry mining face and the track drift to monitor the gas concentration in the mining area in real time.

[0013] S8: Determine the required air volume of the gob-retaining mining face based on the climatic conditions of the gob-retaining mining face, gas emission, carbon dioxide emission, number of workers, and wind speed standards.

[0014] S9: The required air volume for the gob-retained tunnel is determined based on the gas concentration at the gob-retained tunnel mining face and the intersection of the track drift.

[0015] S10: By adjusting the operating parameters of the local fans of the belt chute and the air inlet chute of the next adjacent working face, the air volume of the mining working face along the goaf and the air volume in the goaf-retained lane can be ensured to meet the production requirements.

[0016] S11: Before mining along the gob-retaining mining face, directional blasting holes are constructed along the cutting top line on the top plate of the track drift. The directional blasting holes are perpendicular to the top plate of the track drift.

[0017] S12: A directional focused-energy blasting tube is installed in the directional blasting hole, and energy release holes are opened on both sides of the directional focused-energy blasting tube. The energy release holes on both sides of the directional focused-energy blasting tube are parallel to the track groove.

[0018] S13: Explosives are installed in the directional shaped charge blasting tube. The explosives filling position is the basic top thickness part in the directional blasting hole, and the sealing hole depth is the direct top thickness part.

[0019] S14: Directional blasting is performed on the top plate of the track channel to fracture the basic top along the direction of the track channel, and it is ensured that the cracks between the basic tops of each directional blasting hole are directly connected and no cracks are formed on the direct top.

[0020] S15: Mining is carried out on the mining face along the goaf, and after advancement, the construction of flexible formwork filling support wall is carried out in time to form goaf-retained goaf.

[0021] S16: As the goaf-side entry-retaining mining face advances, a groove is dug in advance on the bottom plate of the goaf-side entry-retaining mining face, and a gas extraction pipe is arranged inside the groove.

[0022] S17: With the advancement of the mining face and the increasing distance of the gob-retained gob, in the gob-retained gob stable zone, a directional blasting hole is opened every 10 directional blasting holes, a gas extraction pipe is arranged inside it, and the hole is sealed again. The sealing depth is the thickness of the direct roof.

[0023] S18: Connect the gas extraction pipes in the trench and the gas extraction pipes in the directional blasting hole to the low-negative pressure extraction pipe network along the gob-retained lane.

[0024] S19: As the mining face of the gob-retained tunnel advances, continuous extraction begins after the gas extraction pipe enters the stable zone of the gob-retained tunnel, and the extraction negative pressure is determined based on the gas concentration in the gob-retained tunnel.

[0025] Furthermore, in step S3, four local fans are installed in the air inlet tunnel, two for use and two for standby.

[0026] Furthermore, in step S11, the spacing between directional blasting holes is 1-2m, the diameter of the directional blasting holes is 75mm, the directional blasting holes are 2-2.5m away from the side of the drift side of the gob-side entry mining face, and the depth of the directional blasting holes is the total thickness of the direct top plus the basic top.

[0027] Furthermore, in step S15, the thickness of the flexible formwork filling support wall is 1.5-2m.

[0028] Furthermore, in step S16, the interval between the cuts is 30-50 m, and the lengths of the cuts are of two types, 5 m and 50 m, and are distributed at intervals.

[0029] Furthermore, in step S17, the cracks between the openings of the directional blasting holes are sealed with air leakage plugging materials.

[0030] The coal pillar-free mining technology along the goaf can save a lot of coal resources, but it brings new problems such as complex gas outburst rules of the working face and serious gas over-limit in the goaf-retained goaf. Therefore, the present invention provides a comprehensive gas disaster prevention and control method for the goaf-retained goaf working face to solve the above problems. The method of the present invention realizes effective gas prevention and control through "W-type local pressurization" ventilation and top-bottom plate gas three-dimensional extraction. The method of the present invention is to install a local fan in the air inlet tunnel after the goaf-retained goaf mining working face is formed, and the local fan supplies air to the belt chute and the next adjacent working face air inlet chute through the wind tube, and the rail chute is installed with an adjustable damper, and the "W-type local pressurization" method is adopted to supply air to the working face, and the wind pressure of the mining field is adjusted by adjusting the parameters of the local fan and the adjustable damper, so as to seal and control the gas outburst of the upper and lower adjacent layers and the goaf. At the same time, a directional blasting hole constructed along the top cutting line is arranged in the rail chute (goaf-retained goaf), and a crack parallel to the goaf-retained goaf is formed by directional concentrated energy blasting, so as to cut off the basic top while maintaining the integrity of the direct top. After the top is cut, the blasting hole is transformed into a gas extraction hole, the cracks in the drill hole and the direct top are blocked, and the gas extraction of the roof along the goaf is carried out. At the same time, before the working face is mined, a groove is dug in the bottom plate and a gas extraction pipe is buried. After the gas extraction pipe enters the goaf area, the gas in the bottom plate is extracted.

[0031] Compared with the prior art, the comprehensive gas disaster prevention and control method for gob-side tunnel retaining working face adopted by the present invention mainly has the following beneficial effects: (1) Through W-shaped local pressurization, the pressure of the airflow in the mining area is significantly increased, which solves the problem of spontaneous combustion in the goaf caused by "Y-shaped ventilation". It can also effectively reduce the gas outflow from the upper and lower adjacent layers to the working face and the gas outflow from the goaf of the working face to the tunnel, greatly reducing the gas outflow from the working face.

[0032] (2) While the roof was cut to relieve pressure, a fully connected basic roof fissure channel was formed, which promoted the efficient extraction of gas from the roof fissures and achieved multiple uses of one hole, greatly reducing the drilling construction volume and construction costs. The floor extraction drilling holes were arranged in advance before the working face was mined, which solved the problem of the difficulty in laying the extraction pipes and the easy crushing of the extraction pipes in the existing goaf buried pipe extraction technology. Finally, a three-dimensional gas extraction system of the roof and floor along the goaf was formed, which achieved effective prevention and control of gas in the goaf. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings herein are used to provide further explanation of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 The present invention is a site layout plan of a comprehensive gas disaster prevention and control method for a goaf-side tunnel retaining working face.

[0035] Figure 2 It is a site layout inclination profile diagram of a comprehensive gas disaster prevention and control method for a goaf-side tunnel retaining working face according to the present invention.

[0036] Figure 3 This is a cross-sectional view of the on-site layout of a comprehensive gas disaster prevention and control method for a goaf-side tunnel-retaining working face according to the present invention.

[0037] In the figure: 1-track drift, 2-belt drift, 3-air inlet drift of the next adjacent mining face, 4-next adjacent mining face, 5-air inlet main tunnel, 6-tunnel along the goaf, 7-directional blasting hole, 8-groove, 9-gas extraction pipe, 10-flexible formwork filling support wall, 11-explosive burial section, 12-sealing section, 13-direct top, 14-basic top, 15-adjusting damper, 16-local fan, 17-mining face with tunnel along the goaf. DETAILED DESCRIPTION

[0038] In order to make those skilled in the art better understand the present invention, the present invention is further clearly and completely described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the features in the embodiments and examples of this application can be combined with each other.

[0039] like Figures 1 to 3 As shown, this embodiment provides a comprehensive prevention and control method for gas disasters in a gob-side tunnel retaining working face, comprising the following steps: S1: Using the coal pillar-free mining technology with gob-side entry retention, two adjacent working faces are excavated, namely the gob-side entry retention mining working face 17 and the next adjacent mining working face 4.

[0040] S2: After the gob-side entry retaining mining face 17 is formed, an adjusting damper 15 is installed at the head of the track drift 1.

[0041] S3: Install a local fan 16 in the air inlet tunnel 5; specifically, install four local fans 16, two for use and two for standby.

[0042] S4: The outlet of the local fan 16 supplies air to the belt chute 2 and the next adjacent working surface air inlet chute 3 through the air duct.

[0043] S5: By adjusting the size of the local fan 16 and the damper 15 in the track chute 1, the air volume and pressure in the mining area are controlled to achieve air supply in the "W-shaped local pressurization" mode for the mining working face 17 along the gob retaining lane.

[0044] S6: Install U-shaped differential pressure gauges on both sides of the regulating damper 15, and monitor the internal air flow pressure of the gob-side entry-retaining mining working face 17 through the readings of the U-shaped differential pressure gauges.

[0045] S7: Gas concentration sensors are arranged at the intersection of the gob-side entry mining face 17 and the track drift 1 to monitor the gas concentration in the mining area in real time.

[0046] S8: Determine the required air volume of the gob-retaining mining face 17 according to the climate conditions of the gob-retaining mining face 17, the gas emission, the carbon dioxide emission, the number of workers, and the wind speed standard.

[0047] S9: Determine the required air volume of the gob-side retaining lane 6 according to the gas concentration at the intersection of the gob-side retaining lane mining face 17 and the track drift 1.

[0048] S10: By adjusting the operating parameters of the local fan 16 of the belt chute 2 and the air inlet chute 3 of the next adjacent working face, it is ensured that the air volume of the gob-side tunnel recovery working face 17 and the air volume in the gob-side tunnel 6 meet the production requirements.

[0049] S11: Before mining the goaf-retaining mining face 17, directional blasting holes 7 are constructed along the top cutting line on the top plate of the track drift 1. The directional blasting holes 7 are perpendicular to the top plate of the track drift 1. Specifically, the spacing between the directional blasting holes 7 is 1-2m, the diameter of the directional blasting holes 7 is 75mm, the directional blasting holes 7 are 2-2.5m away from the side of the goaf-retaining mining face 17, and the depth of the directional blasting holes 7 is the total thickness of the direct top 13 plus the basic top 14.

[0050] S12: A directional focused-energy blasting tube is installed in the directional blasting hole 7 , and energy release holes are provided on both sides of the directional focused-energy blasting tube. The energy release holes on both sides of the directional focused-energy blasting tube are parallel to the track chute 1 .

[0051] S13: Explosives are installed in the directional shaped charge blasting tube. The explosive filling position is the thickness of the basic top 14 in the directional blasting hole 7, that is, the length of the explosive burying section 11 is the thickness of the basic top 14; the sealing depth is the thickness of the direct top 13, that is, the length of the sealing section 12 is the thickness of the direct top 13.

[0052] S14: Directional blasting is performed on the top plate of the track channel 1 to fracture the basic top 14 along the direction of the track channel 1, and it is ensured that the cracks between the basic tops 14 of each directional blasting hole 7 are directly connected, and no cracks are formed in the direct top 13.

[0053] S15: Mining the gob-side entry-retaining mining face 17, and constructing the flexible formwork filling support wall 10 in a timely manner after advancement, so as to form the gob-side entry-retaining 6; specifically, the thickness of the flexible formwork filling support wall 10 is 1.5-2m.

[0054] S16: With the advancement of the gob-side lane-retaining mining face 17, a groove 8 is excavated in advance on the bottom plate of the gob-side lane-retaining mining face 17, and a gas extraction pipe 9 is arranged inside the groove 8; specifically, the interval between the grooves 8 is 30-50m, and the lengths of the grooves 8 are of two types, 5m and 50m, and are distributed at intervals.

[0055] S17: With the advancement of the mining face 17 along the goaf and the increasing distance between the goaf and the goaf 6, in the stable area of ​​the goaf 6, a directional blasting hole 7 is opened every 10 directional blasting holes 7, a gas extraction pipe 9 is arranged inside the directional blasting hole, and the hole is sealed again. The sealing depth is the thickness of the direct roof 13, and at the same time, the cracks between the hole openings of the directional blasting holes 7 are sealed with air leakage plugging materials.

[0056] S18: Connect the gas extraction pipe 9 in the cutout 8 and the gas extraction pipe 9 in the directional blasting hole 7 to the low-negative pressure extraction pipe network along the gob-retained lane.

[0057] S19: As the mining face 17 along the gob-retained lane advances, the gas extraction pipe 9 starts continuous extraction after entering the stable zone of the gob-retained lane 6, and determines the extraction negative pressure based on the gas concentration in the gob-retained lane 6.

[0058] In the comprehensive prevention and control method for gas disasters in a gob-side entry retaining working face provided in this embodiment: like Figure 1 As shown, a "W-shaped local pressurization" ventilation mode is formed by the track chute 1 (plus the goaf-retaining lane 6), the belt chute 2 and the next adjacent working face air inlet chute 3. Through this ventilation technology, the pressure of the airflow in the mining field is significantly improved, which solves the problem of "Y-shaped ventilation" easily causing spontaneous combustion in the goaf, and can effectively reduce the gas outflow from the upper and lower adjacent layers to the goaf-retaining lane mining face 17 and the gas outflow from the goaf of the goaf-retaining lane mining face 17 to the tunnel, greatly reducing the gas outflow from the goaf-retaining lane mining face 17.

[0059] like Figure 2 , 3 As shown, the gas extraction pipe 9 in the directional blasting hole 7 on the roof is mainly used to intercept the fissure gas in the roof of the goaf area, and the gas extraction pipe 9 in the cutout 8 on the floor is mainly used to intercept the fissure gas in the floor of the goaf area. The gas extraction pipe 9 in the directional blasting hole 7 and the gas extraction pipe 9 in the cutout 8 form a three-dimensional cross network, realizing all-round extraction in the goaf area and effectively solving the problem of three-dimensional gas outflow in the goaf-retained lane 6.

[0060] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A comprehensive method for preventing and controlling gas disasters in a gob-side tunnel-retaining working face, characterized in that: The following steps are involved: S1: Using the coal pillar-free mining technology with gob-side entry retention, two adjacent working faces are excavated, namely the gob-side entry retention mining working face (17) and the next adjacent mining working face (4); S2: After the gob-side entry retaining mining working face (17) is formed, an adjusting air door (15) is installed at the head of the track drift (1); S3: Install a local fan (16) in the air inlet tunnel (5); S4: The outlet of the local fan (16) supplies air to the belt chute (2) and the next adjacent working surface air inlet chute (3) through the air duct; S5: by adjusting the size of the local fan (16) and the air door (15) in the track chute (1), the air volume and pressure in the mining area are controlled to achieve air supply in a "W-shaped local pressurization" manner at the gob-side entry mining working face (17); S6: Install U-shaped differential pressure gauges on both sides of the regulating damper (15), and monitor the internal air flow pressure of the gob-side entry retaining mining working face (17) through the readings of the U-shaped differential pressure gauges; S7: a gas concentration sensor is arranged at the intersection of the gob-side entry mining face (17) and the track drift (1) to monitor the gas concentration in the mining area in real time; S8: Determine the required air volume of the gob-side entry-retaining mining working face (17) according to the climate conditions, gas emission, carbon dioxide emission, number of workers, and wind speed standard of the gob-side entry-retaining mining working face (17); S9: determining the required air volume of the gob-side entry (6) according to the gas concentration at the intersection of the gob-side entry mining face (17) and the track drift (1); S10: by adjusting the operating parameters of the local fan (16) of the belt chute (2) and the air inlet chute (3) of the next adjacent working face, the air volume of the gob-side entry mining working face (17) and the air volume in the gob-side entry (6) meet the production requirements; S11: Before mining the gob-side entry retaining mining working face (17), a directional blasting hole (7) is constructed along the top cutting line on the top plate of the track drift (1), wherein the directional blasting hole (7) is perpendicular to the top plate of the track drift (1); S12: installing a directional blasting tube in the directional blasting hole (7), with energy release holes being provided on both sides of the directional blasting tube, and the energy release holes on both sides of the directional blasting tube being parallel to the track groove (1); S13: installing explosives in the directional shaped charge blasting tube, the explosives filling position is the thickness of the basic top (14) in the directional blasting hole (7), and the sealing depth is the thickness of the direct top (13); S14: Directional blasting is performed on the top plate of the track chute (1) to fracture the basic top (14) along the direction of the track chute (1), and it is ensured that the cracks between the basic tops (14) of the various directional blasting holes (7) are directly connected, and no cracks are formed in the direct top (13); S15: mining the gob-side entry retaining mining working face (17), and after advancing, promptly constructing the flexible formwork filling support wall (10), thereby forming the gob-side entry retaining (6); S16: As the gob-side entry retaining mining face (17) advances, a groove (8) is cut in advance on the floor of the gob-side entry retaining mining face (17), and a gas extraction pipe (9) is arranged inside the groove (8); S17: As the gob-side entry retaining mining face (17) advances and the distance of the gob-side entry retaining (6) increases, in the gob-side entry retaining (6) entry stability zone, a directional blasting hole (7) is opened every 10 directional blasting holes (7), a gas extraction pipe (9) is arranged inside the directional blasting hole, and the hole is sealed again, and the sealing depth is the thickness of the immediate roof (13); S18: Connecting the gas extraction pipe (9) in the cutout (8) and the gas extraction pipe (9) in the directional blasting hole (7) to the low-negative-pressure extraction pipe network along the gob-retained lane; S19: As the mining face (17) of the gob-side retained lane advances, the gas extraction pipe (9) enters the stable zone of the gob-side retained lane (6) and starts continuous extraction.

2. A comprehensive gas disaster prevention and control method for gob-side entry retaining working face according to claim 1, characterized in that: In step S3, four local fans (16) are installed in the air inlet tunnel (5), two for use and two for standby.

3. A comprehensive method for preventing and controlling gas disasters in a gob-side entry retaining working face according to claim 1, characterized in that: In step S11, the spacing of the directional blasting holes (7) is 1-2 m, the diameter of the directional blasting holes (7) is 75 mm, the directional blasting holes (7) are 2-2.5 m away from the side of the drift side of the gob-side entry-retaining mining working face (17), and the depth of the directional blasting holes (7) is the total thickness of the direct roof (13) plus the basic roof (14).

4. A comprehensive method for preventing and controlling gas disasters in a gob-side entry retaining working face according to claim 1, characterized in that: In step S15, the thickness of the flexible formwork filling support wall (10) is 1.5-2 m.

5. A comprehensive gas disaster prevention and control method for gob-side entry retaining working face according to claim 1, characterized in that: In step S16, the spacing distance of the cutouts (8) is 30-50 m, and the lengths of the cutouts (8) are of two types, 5 m and 50 m, and are distributed at intervals.

6. A comprehensive gas disaster prevention and control method for gob-side entry retaining working face according to claim 1, characterized in that: In step S17, the cracks between the openings of the directional blasting holes (7) are sealed with air leakage plugging materials.

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