A comprehensive prevention and control method for gas disasters in gob-side entry retaining working faces

Abstract

The invention discloses a comprehensive prevention and control method for gas disasters in gob-side entry retaining working faces, belonging to the technical field of mine gas disaster prevention and control. In the invention, a local fan is installed in the intake main roadway, and the local fan supplies air to the belt conveyor gateway and the intake gateway of the next adjacent working face through an air duct. A regulating air door is installed in the track gateway, and the "W-shaped local pressurization" method is adopted to supply air to the working face, and the air pressure in the stope is adjusted by controlling the parameters of the local fan and the regulating air door. Directional blasting holes are arranged in the track gateway, and cracks parallel to the gob-side entry retaining are formed through directional shaped charge blasting. After roof cutting is completed, the blasting holes are transformed into gas drainage holes for gas drainage from the roof of the gob-side entry retaining. At the same time, before the gob-side entry retaining working face is mined, a cut is made in the floor and a gas drainage pipe is buried. After the gas drainage pipe enters the goaf, the gas in the floor is drained. The method of the invention greatly reduces the gas emission amount in the working face and realizes the effective prevention and control of gas in the gob-side entry retaining.

Description

Technical Field

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

[0002] With the increase of coal mining depth and intensity, the stope structure becomes 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 obvious. More complex gas dynamic disasters will accompany the deep coal mining process, which is extremely likely to cause major accidents.

[0003] When mining coal seam groups, the gob-side entry retaining pillarless mining technology of the protective seam is an effective means for outburst prevention in the outburst mine area. Gob-side entry retaining mining can reduce the influence of stress concentration generated by the reserved coal pillar on the pressure relief range of the protected seam, improve the pressure relief effect of the protective seam, and reduce the driving workload of the outburst coal seam and the amount of reserved coal pillars. In addition, with the gradual depletion of coal resources, more and more mines urgently need to promote the gob-side entry retaining pillarless mining technology to reduce the large amount of coal loss caused by the protective coal pillars. However, there are huge safety hazards when this technology is used in mines with complex conditions. Specifically, the gob-side entry retaining roadway is prone to deformation and difficult to support, the gob has serious air leakage, large gas emission, and serious spontaneous combustion in Y-type ventilation. Among them, gas can gush out three-dimensionally from the gob-side entry retaining roadway rib, roof, and floor, with a large emission volume. The gas in the gob-side entry retaining roadway is prone to exceeding the limit, and it is difficult to prevent and control gas disasters.

[0004] Therefore, it is urgent to control the gas in the gob-side entry retaining roadway. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of serious deformation of the gob-side entry retaining roadway, large three-dimensional gas emission, and easy occurrence of coal spontaneous combustion in Y-type ventilation during the gob-side entry retaining pillarless mining in high-gas mines, and to provide a comprehensive prevention and control method for gas disasters in gob-side entry retaining working faces.

[0006] The present invention is realized by the following technical solutions:

[0007] A comprehensive prevention and control method for gas disasters in gob-side entry retaining working faces includes the following steps:

[0008] S1: Using the gob-side entry retaining pillarless mining technology, two adjacent working faces are excavated, namely the gob-side entry retaining mining working face and the next adjacent mining working face.

[0009] S2: After the gob-side entry retaining mining working face is formed, an adjusting air door is installed at the head of the track gateway.

[0010] S3: Install a local fan in the intake airway.

[0011] S4: The outlet of the local fan supplies air to the belt gateway and the intake airway of the next adjacent working face through the air duct.

[0012] S5: By adjusting the sizes of the local fan and the regulating air doors in the track gateway, the air volume and pressure in the stope are controlled to realize the air supply to the gob-side entry retaining working face in the way of "W-shaped local pressurization". Among them, a "W-shaped local pressurization" ventilation mode is formed among the track gateway, the belt gateway and the intake airway of the next adjacent working face.

[0013] S6: U-shaped differential pressure gauges are installed on both sides of the regulating air doors, and the internal air flow pressure of the gob-side entry retaining working face is monitored through the readings of the U-shaped differential pressure gauges.

[0014] S7: Gas concentration sensors are arranged at the intersection of the gob-side entry retaining working face and the track gateway to monitor the gas concentration in the stope in real time.

[0015] S8: The required air volume of the gob-side entry retaining working face is determined according to the climatic conditions, gas emission volume, carbon dioxide emission volume, number of workers and wind speed standard of the gob-side entry retaining working face.

[0016] S9: The required air volume of the gob-side entry retaining is determined according to the gas concentration at the intersection of the gob-side entry retaining working face and the track gateway.

[0017] S10: By adjusting the operating parameters of the local fans in the belt gateway and the intake airway of the next adjacent working face, the air volume of the gob-side entry retaining working face and the air volume in the gob-side entry retaining are ensured to meet the production requirements.

[0018] S11: Before the gob-side entry retaining working face is mined, directional blasting holes are constructed along the roof cutting line on the roof of the track gateway, and the directional blasting holes are perpendicular to the roof of the track gateway.

[0019] S12: Directional shaped charge blasting pipes are installed in the directional blasting holes. Energy release holes are opened on both sides of the directional shaped charge blasting pipes, and the energy release holes on both sides of the directional shaped charge blasting pipes are parallel to the track gateway.

[0020] S13: Explosives are installed in the directional shaped charge blasting pipes. The filling position of the explosives is the part of the main roof thickness in the directional blasting holes, and the stemming depth is the part of the immediate roof thickness.

[0021] S14: Directional blasting is carried out on the roof of the track gateway to fracture the main roof along the direction of the track gateway, and it is ensured that the fissures between the main roofs of each directional blasting hole are directly conducted, and no fissures are formed in the immediate roof.

[0022] S15: The gob-side entry retaining working face is mined, and the flexible formwork filling support wall is constructed in time after advancing to form the gob-side entry retaining.

[0023] S16: As the gob-side entry retaining mining face advances, pre-slotting is carried out on the floor of the gob-side entry retaining mining face in advance, and a gas drainage pipe is arranged inside the slot.

[0024] S17: As the gob-side entry retaining mining face advances and the distance of gob-side entry retaining continuously increases, in the stable area of the formed gob-side entry retaining, one of every 10 directional blasting holes is opened, a gas drainage pipe is arranged inside it, and sealing is carried out again, and the sealing depth is the part of the thickness of the immediate roof.

[0025] S18: Connect the gas drainage pipes in the slots and the gas drainage pipes in the directional blasting holes to the low-negative-pressure gas drainage network of the gob-side entry retaining.

[0026] S19: As the gob-side entry retaining mining face advances, continuous drainage starts after the gas drainage pipe enters the stable area of the formed gob-side entry retaining, and the drainage negative pressure is determined according to the gas concentration in the gob-side entry retaining.

[0027] Further, in step S3, four local fans are installed in the intake main roadway, two are in use and two are in reserve.

[0028] Further, in step S11, the spacing of the directional blasting holes is 1 - 2 m, the diameter of the directional blasting holes is 75 mm, the directional blasting holes are 2 - 2.5 m away from the side roadway rib of the gob-side entry retaining mining face on one side, and the depth of the directional blasting holes is the total thickness of the immediate roof plus the main roof.

[0029] Further, in step S15, the thickness of the flexible mold filling support wall is 1.5 - 2 m.

[0030] Further, in step S16, the interval distance of the slots is 30 - 50 m, the lengths of the slots are two types, 5 m and 50 m, and they are distributed at intervals.

[0031] Further, in step S17, the cracks between the orifices of the directional blasting holes are sealed with air leakage prevention materials.

[0032] The technology of gob-side entry retaining without coal pillars can save a large amount of coal resources, but it brings new problems such as the complex law of gas emission in the working face and serious gas overrun in the gob-side entry retaining. Therefore, the present invention provides a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face to solve the above problems. The method of the present invention realizes the effective prevention and control of gas through "W-type local pressurization" ventilation and three-dimensional gas extraction from the roof and floor. After the gob-side entry retaining working face is formed, a local fan is installed in the intake main roadway. The local fan supplies air to the belt gateway and the intake gateway of the next adjacent working face through air ducts. A regulating air door is installed in the track gateway, and the air is supplied to the working face in the way of "W-type local pressurization", and the air pressure in the stope is adjusted by regulating the parameters of the local fan and the regulating air door, so as to seal the gas emission from the upper and lower adjacent strata and the goaf. At the same time, directional blasting holes are arranged along the roof cutting line in the track gateway (gob-side entry retaining), and cracks parallel to the gob-side entry retaining are formed through directional shaped charge blasting, while maintaining the integrity of the immediate roof while cutting the main roof. After the roof cutting is completed, the blasting holes are transformed into gas extraction holes, and the cracks in the boreholes and the immediate roof are sealed to extract the gas from the roof of the gob-side entry retaining. At the same time, before the working face is mined, a groove is dug in the floor and a gas extraction pipe is buried. After the gas extraction pipe enters the goaf, the gas in the floor is extracted.

[0033] Compared with the prior art, a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face adopted by the present invention mainly has the following beneficial effects:

[0034] (1) Through the W-type local pressurization, the pressure of the air flow in the stope is significantly increased, which not only solves the problem of spontaneous combustion in the goaf easily caused by "Y-type ventilation", but also effectively reduces the gas emission from the upper and lower adjacent strata to this working face and the gas emission from the goaf of this working face to the roadway, greatly reducing the gas emission amount in the working face.

[0035] (2) While relieving the pressure by roof cutting, a fully penetrated main roof fracture channel is formed, which promotes the efficient extraction of roof fracture gas, realizes the multi-purpose use of one hole, greatly reduces the drilling construction amount and construction cost; before the working face is mined, the floor extraction boreholes are arranged in advance, which solves the problems of difficult laying of the gas extraction pipe and easy being crushed in the existing goaf buried pipe gas extraction technology; finally, a three-dimensional gas extraction system for the roof and floor of the gob-side entry retaining is formed, realizing the effective prevention and control of the gas in the gob-side entry retaining. Description of the Drawings

[0036] The drawings here are used to provide further illustration of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0037] Figure 1 It is the site layout plan of a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face of the present invention.

[0038] Figure 2 This is the inclined sectional view of the on-site layout of a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face of the present invention.

[0039] Figure 3 This is the strike sectional view of the on-site layout of a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face of the present invention.

[0040] In the figure: 1 - Track gateway, 2 - Belt gateway, 3 - Intake airway of the next adjacent mining working face, 4 - Next adjacent mining working face, 5 - Main intake airway, 6 - Gob-side entry retaining, 7 - Directional blasting hole, 8 - Cut, 9 - Gas drainage pipe, 10 - Flexible mold filling support wall, 11 - Explosive placement section, 12 - Sealing section, 13 - Immediate roof, 14 - Main roof, 15 - Regulating air door, 16 - Local fan, 17 - Gob-side entry retaining mining working face. Specific implementation mode

[0041] In order to enable those skilled in the art to better understand the present invention, the present invention will be further clearly and completely described below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, without conflict, the implementation modes and features in the embodiments of the present application can be combined with each other.

[0042] As Figures 1 to 3 shown, this embodiment provides a comprehensive prevention and control method for gas disasters in the gob-side entry retaining working face, including the following steps:

[0043] S1: Using the gob-side entry retaining non-pillar mining technology, two adjacent working faces are excavated, namely the gob-side entry retaining mining working face 17 and the next adjacent mining working face 4.

[0044] S2: After the gob-side entry retaining mining working face 17 is formed, a regulating air door 15 is installed at the head of the track gateway 1.

[0045] S3: Install local fans 16 in the main intake airway 5; specifically, four local fans 16 are installed, two are in use and two are in standby.

[0046] S4: The outlet of the local fan 16 supplies air to the belt gateway 2 and the intake airway of the next adjacent working face 3 through an air duct.

[0047] S5: By adjusting the sizes of the local fan 16 and the regulating air door 15 in the track gateway 1, the air volume and pressure of the stope are controlled to realize the air supply to the gob-side entry retaining mining working face 17 in the way of "W-type local pressure increase".

[0048] S6: Install U-shaped differential pressure gauges on both sides of the regulating air door 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.

[0049] S7: Install a gas concentration sensor at the intersection of the gob-side entry retaining mining face 17 and the track gateway 1 to monitor the gas concentration in the stope in real time.

[0050] S8: Determine the required air volume of the gob-side entry retaining mining face 17 according to the climatic conditions, gas emission volume, carbon dioxide emission volume, number of workers, and wind speed standard of the gob-side entry retaining mining face 17.

[0051] S9: Determine the required air volume of the gob-side entry 6 according to the gas concentration at the intersection of the gob-side entry retaining mining face 17 and the track gateway 1.

[0052] S10: By adjusting the operating parameters of the local fan 16 in the belt gateway 2 and the intake airway 3 of the next adjacent working face, ensure that the air volume of the gob-side entry retaining mining face 17 and the air volume in the gob-side entry 6 meet the production requirements.

[0053] S11: Before the gob-side entry retaining mining face 17 is mined, construct directional blasting holes 7 along the roof cutting line of the track gateway 1. The directional blasting holes 7 are perpendicular to the roof of the track gateway 1. Specifically, 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 roadway rib of the gob-side entry retaining mining face 17, and the depth of the directional blasting holes 7 is the total thickness of the immediate roof 13 plus the main roof 14.

[0054] S12: Install a directional shaped charge blasting pipe in the directional blasting hole 7. Energy release holes are opened on both sides of the directional shaped charge blasting pipe, and the energy release holes on both sides of the directional shaped charge blasting pipe are parallel to the track gateway 1.

[0055] S13: Install explosives in the directional shaped charge blasting pipe. The explosive filling position is the part of the main roof 14 thickness in the directional blasting hole 7, that is: the length of the explosive placement section 11 is the thickness of the main roof 14; the stemming depth is the part of the immediate roof 13 thickness, that is: the length of the stemming section 12 is the thickness of the immediate roof 13.

[0056] S14: Conduct directional blasting on the roof of the track gateway 1 to fracture the main roof 14 along the direction of the track gateway 1, and ensure that the fissures between the directional blasting holes 7 in the main roof 14 are directly connected, and no fissures are formed in the immediate roof 13.

[0057] S15: Mine the gob-side entry retaining mining face 17, and promptly construct the flexible formwork filling support wall 10 after advancing to form the gob-side entry 6. Specifically, the thickness of the flexible formwork filling support wall 10 is 1.5 - 2 m.

[0058] S16: As the gob-side entry retaining mining face 17 advances, a cut 8 is made in advance at the floor of the gob-side entry retaining mining face 17, and a gas drainage pipe 9 is arranged inside the cut 8. Specifically, the interval distance of the cuts 8 is 30 - 50 m, and the lengths of the cuts 8 are of two types, 5 m and 50 m, and they are distributed at intervals.

[0059] S17: As the gob-side entry retaining mining face 17 advances and the distance of the gob-side entry retaining 6 continuously increases, in the stable area of the gob-side entry retaining 6 where the roadway is formed, one of every 10 directional blasting holes 7 is opened, a gas drainage pipe 9 is arranged inside it, and sealing is carried out again. The sealing depth is the part of the thickness of the immediate roof 13, and at the same time, the cracks between the orifices of the directional blasting holes 7 are sealed with air leakage prevention materials.

[0060] S18: Connect the gas drainage pipes 9 in the cuts 8 and the gas drainage pipes 9 in the directional blasting holes 7 to the low negative pressure gas drainage pipeline network in the gob-side entry retaining.

[0061] S19: As the gob-side entry retaining mining face 17 advances, after the gas drainage pipe 9 enters the stable area of the gob-side entry retaining 6 where the roadway is formed, continuous drainage starts, and the drainage negative pressure is determined according to the gas concentration in the gob-side entry retaining 6.

[0062] In a comprehensive prevention and control method for gas disasters in a gob-side entry retaining working face provided by this embodiment:

[0063] As Figure 1 shown, the "W-shaped local pressurization" ventilation mode is formed by the track gateway 1 (plus the gob-side entry retaining 6), the belt gateway 2 and the intake airway 3 of the next adjacent working face. Through this ventilation technology, the pressure of the air flow in the mining area is significantly increased, that is, the problem of spontaneous combustion in the goaf easily caused by the "Y-shaped ventilation" is solved, and at the same time, the gas emission from the upper and lower adjacent coal seams to the gob-side entry retaining mining face 17 and the gas emission from the goaf of the gob-side entry retaining mining face 17 to the roadway can be effectively reduced, greatly reducing the gas emission amount of the gob-side entry retaining mining face 17.

[0064] As Figure 2 、 3 shown, the gas drainage 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, and the gas drainage pipe 9 in the cut 8 on the floor is mainly used to intercept the fissure gas in the floor of the goaf. The gas drainage pipes 9 in the directional blasting holes 7 and the gas drainage pipes 9 in the cuts 8 form a three-dimensional cross network, realizing the all-round drainage of the goaf and effectively solving the problem of three-dimensional gas emission in the gob-side entry retaining 6.

[0065] The above-described embodiments merely represent one implementation mode of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all fall within 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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