Stereo ventilation method and system for multi-seam mining in coal and gas outburst mine

Abstract

This application relates to the field of mine ventilation technology, and particularly to a three-dimensional ventilation method and system for multi-seam mining in coal and gas outburst mines. A safe and efficient three-dimensional ventilation method is designed. By using the technology of roof cutting and pressure relief to form a roadway without coal pillars, two crossheadings and the cutting roadway of the coal mining face are left. Then, adjacent coal seams are connected through the return air connection roadway and the retained crossheading to form a three-dimensional ventilation of the coal seams. This layout method is cycled to complete the layout of the ventilation system for the entire mining area. Compared with the prior art, it has the following technical effects: a perfect ventilation system can be formed in the retained roadway section; the tunneling workload at the initial stage of mining each coal seam is reduced. After using the cutting roadway and the two retained crossheadings left by adjacent coal seams through the technology of roof cutting and pressure relief to form a roadway without coal pillars, the three-sided and four-roadway structure does not need to be formed in the working face of this coal seam, reducing the initial tunneling workload and improving the normal production efficiency of the coal mine; realizing the three-dimensional ventilation of adjacent coal seams is convenient for controlling the air volume and air flow in the entire mining area.

Description

Technical Field

[0001] This application relates to the technical field of mine ventilation, and specifically relates to a three-dimensional ventilation method and system applicable to multi-seam mining in coal and gas outburst mines, and particularly relates to a three-dimensional ventilation method for outburst coal seam groups. Background Art

[0002] Outburst coal seam groups are widely distributed, have large reserves, and high mining intensities in China's coal resources. When mining outburst coal seam groups, generally, the downward mining method of first mining the upper coal seam and then the lower coal seam is selected. In special cases, according to the gas parameters and mining technical conditions of the coal seam group, the middle or lower coal seam is selected as the protective seam for mining. At this time, it is necessary to adopt the upward mining method of first mining the middle or lower coal seam to reduce or eliminate the coal and gas outburst danger of the upper coal seam. When the protective seam is of poor quality, thin, and unstable coal seams, in order to ensure the mining efficiency, the upward mining and downward mining combination method can be used to mine the coal seams. When using traditional mining techniques for mining (as shown in Figure 1 ), coal pillars are reserved between working faces, and stress concentration occurs around the coal pillars, resulting in large deformations of the surrounding rock of the roadways in the upper or lower coal seams, posing safety hazards and affecting the normal production efficiency. After adopting the "110" method of roof cutting and pressure relief without coal pillar to form a roadway by itself, many problems such as serious deformation of the surrounding rock of the roadway, improvement of coal recovery rate, and reduction of the tunneling rate per 10,000 tons of coal mines can be solved. Especially in coal and gas outburst mines, excavating one less mining roadway can reduce the gas control workload and time by about 50%, and can effectively solve the problem of difficult mining and tunneling succession in outburst mines. However, when using the roof cutting and pressure relief without coal pillar roadway forming technology to layout the first mining working face of the protective seam with two crosshead roadways, there is no return air passage in the roadway retaining section (as shown in Figure 2 ), and a perfect return air system cannot be formed, bringing many safety hazards to coal mine production; or in order to meet the ventilation requirements, it is necessary to layout three sides and four roadways (as shown in Figure 3 ), and the initial tunneling workload is large, affecting the normal production efficiency of coal mines.

[0003] Based on the comprehensive existing technologies, during the process of using the "110" method for roof cutting and roadway retaining in the mining of outburst coal seam groups before forming the Y-shaped ventilation or W-shaped ventilation, a perfect return air system cannot be formed in the roadway retaining section, which will lead to problems such as the inability to monitor the change of the surrounding rock in the roadway retaining section, the accumulation of toxic and harmful gases in the roadway retaining section, and the inability to drill in the roadway retaining section for gas control, and will also increase the economic cost of coal mine mining. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides the following technical solutions.

[0005] In a first aspect, the present application provides a three-dimensional ventilation method for multi-seam mining in a coal and gas outburst mine. The coal mining area of the mine is a group of outburst coal seams containing several coal seams. The group of outburst coal seams includes a first coal seam and a second coal seam arranged adjacent to each other, where:

[0006] The second working face located in the second coal seam has a second track gateway and a second transportation gateway. The second track gateway is retained through the roof cutting and pressure relief roadway retaining technology to form a first retained roadway, the second transportation gateway is retained through the roof cutting and pressure relief roadway retaining technology to form a second retained roadway, and the cut-through of the second working face is retained through the roof cutting and pressure relief roadway retaining technology to form a third retained roadway;

[0007] Before the first working face in the first coal seam is mined, the first track gateway and the first transportation gateway on both sides of the first working face are constructed, and a first ventilation roadway and a second ventilation roadway are constructed. The two ends of the first ventilation roadway are respectively connected to the first retained roadway and the first track gateway, and the two ends of the second ventilation roadway are connected to the second retained roadway and the first transportation gateway;

[0008] During the mining process of the first working face, the first track gateway forms a fourth retained roadway along with the mining, and the second transportation gateway forms a fifth retained roadway along with the mining, so that the intake air of the third retained roadway enters the first retained roadway through the first ventilation roadway to form return air, and the intake air of the fourth retained roadway enters the second retained roadway through the second ventilation roadway to form return air.

[0009] Further, the ventilation circuit of the group of outburst coal seams includes:

[0010] The air enters through the second retained roadway, the first transportation gateway and the first track gateway, and the return air is discharged through the first retained roadway.

[0011] Further, the ventilation circuit of the group of outburst coal seams further includes:

[0012] A part of the intake air of the first transportation gateway is diverted to the coal mining working face in the first coal seam and converges with the intake air of the first track gateway, and then enters the first retained roadway through the fourth retained roadway and the first ventilation roadway in sequence to form return air;

[0013] Another part of the intake air of the first transportation gateway is diverted to the fifth retained roadway, and then converges with the intake air of the second retained roadway through the second ventilation roadway, and then enters the first retained roadway to form return air.

[0014] Further, after the first working face is mined, the fourth retained roadway and the fifth retained roadway are retained, and a three-dimensional ventilation system is formed with the working face gateways of the unmined coal seams adjacent to the first coal seam, and the ventilation of all the coal seams of the group of outburst coal seams located on the side of the first coal seam where the second coal seam is arranged is completed in sequence by using the same method.

[0015] Further, both the fourth roadway retained and the fifth roadway retained are reserved for use as the gateways on both sides of the unmined coal seams in the first working face.

[0016] Further, the outburst coal seam group further includes a third coal seam adjacent to the second coal seam. The first coal seam and the third coal seam are respectively located on the upper and lower sides of the second coal seam. A perfect ventilation is formed between the third working face in the third coal seam and the second coal seam by the three-dimensional ventilation method as described above.

[0017] Further, before the third working face is mined, the third track gateway and the third conveyor gateway on both sides of the third working face are constructed, and the third ventilation roadway and the fourth ventilation roadway are constructed. The two ends of the third ventilation roadway are respectively connected to the first roadway retained and the third track gateway, and the two ends of the fourth ventilation roadway are connected to the second roadway retained and the third conveyor gateway.

[0018] Further, after the third working face is mined, the third conveyor gateway and the third track gateway are reserved by the roof cutting pressure relief and roadway retaining technology, and a three-dimensional ventilation system is formed with the gateways of the unmined coal seam adjacent to the third coal seam. The ventilation of all the coal seams on the side of the third coal seam where the second coal seam is located in the outburst coal seam group is completed in turn by the same method.

[0019] Further, after the ventilation and mining of a working face in any coal seam are completed, development is carried out from the center of the working face to both sides to complete the mining of the entire coal seam.

[0020] In a second aspect, the embodiment of the present application further provides a three-dimensional ventilation system for a coal and gas outburst mine, which is formed by the three-dimensional ventilation method provided in the first aspect of the embodiment of the present application.

[0021] The above technical solution provided by the embodiment of the present application designs a safe and efficient three-dimensional ventilation method for the mining of multiple coal seams in an outburst coal seam group. By using the roof cutting pressure relief and coal pillar-free self-forming roadway technology, two gateways and the cut-through of the coal mining face are left, and then the adjacent coal seams are connected through the return air connection roadway and the retained gateway to form a three-dimensional ventilation between the coal seams. This layout method is cycled to complete the layout of the ventilation system for the entire mining area. Compared with the prior art, it has the following technical effects:

[0022] (1) A perfect ventilation system can be formed in the retained roadway section. After the three-dimensional ventilation is implemented in the retained roadway section, a perfect ventilation system is formed. Toxic and harmful gases in the goaf and adjacent coal seams no longer accumulate, reducing potential safety hazards such as personnel poisoning and gas explosion.

[0023] (2) The amount of excavation work in the initial stage of mining each coal seam is reduced. By utilizing the cut eyes and two drift lanes retained by the adjacent coal seam through the top cutting and pressure relief technology without coal pillars, the working face of this coal seam does not need to form three sides and four lanes, thus reducing the amount of initial excavation work and improving the normal production efficiency of the coal mine.

[0024] (3) Achieve three-dimensional ventilation of adjacent coal seams. This facilitates the control of air volume and airflow in the entire mining area. At the same time, the remaining tunnels are used to continue to pump out the upper or lower coal seams, avoiding gas exceeding the limit when the upper or lower coal seams are mined at a fast speed, and also achieving safe and efficient mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 To highlight the traditional mining technology tunnel layout of the first mining working face of the protective layer in the coal seam group;

[0028] Figure 2 The layout of the tunnels with two tunnels left for the first mining working face of the protective layer in the prominent coal seam group;

[0029] Figure 3 To highlight the protective layer in the coal seam group, the first mining working face is arranged with three sides and four lanes;

[0030] Figure 4 A schematic diagram of double U-shaped ventilation for the first mining working face of a protective layer in a protruding coal seam group provided in an embodiment of the present application;

[0031] Figure 5 The layout diagram of the mining working faces of the first coal seam and the second coal seam provided in the embodiment of the present application;

[0032] Figure 6 A ventilation route map for achieving three-dimensional ventilation between a first coal seam and a second coal seam provided in an embodiment of the present application;

[0033] Figure 7 The layout diagram of the mining working faces of the third coal seam and the second coal seam provided in the embodiment of the present application;

[0034] Figure 8 A ventilation route map for achieving three-dimensional ventilation between the third coal seam and the second coal seam provided in an embodiment of the present application.

[0035] In the figure:

[0036] 1. Intake main roadway; 2. Return air main roadway; 3. First working face; 4. Second working face; 5. Third working face; 6. First track gateway; 7. First conveyor gateway; 8. Second track gateway; 9. Second conveyor gateway; 10. Third track gateway; 11. Third conveyor gateway; 12. First retained roadway; 13. Second retained roadway; 14. Third retained roadway; 15. First ventilation roadway; 16. Second ventilation roadway; 17. Fourth retained roadway; 18. Fifth retained roadway; 19. First coal mining face; 20. Third ventilation roadway; 21. Fourth ventilation roadway; 22. Sixth retained roadway; 23. Seventh retained roadway; 24. Third coal mining face; 25. Second coal mining face. Detailed implementation manners

[0037] In order to enable those skilled in the art of this technology to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0038] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the drawings and in conjunction with the embodiments.

[0039] As Figure 1 shown, when using the traditional mining technology for coal mining, coal pillars are reserved between the working faces, and stress concentration occurs around the coal pillars, resulting in large deformations of the surrounding rocks of the roadways in the upper or lower coal seams, posing potential safety hazards and affecting the normal production efficiency. After adopting the "110" method of roof cutting and pressure relief without coal pillar to form self-forming roadways, many problems such as serious deformation of the surrounding rocks of the roadways, improvement of coal recovery rate, and reduction of the tunneling rate per ten thousand tons of coal mines can be solved. Especially in coal and gas outburst mines, excavating one less mining roadway can reduce the gas control workload and time by about 50%, and can effectively solve the problem of difficult mining and tunneling succession in outburst mines. However, when using the roof cutting and pressure relief without coal pillar technology to layout the first mining face of the protective layer with two gateway roadways, as Figure 2 shown, there is no return air passage in the retained roadway section, and a perfect return air system cannot be formed, bringing many potential safety hazards to coal mine production; or to meet the ventilation requirements, it is necessary to, as Figure 3The shown layout has three sides and four lanes, with a large initial tunneling workload, which affects the normal production efficiency of the coal mine. During the process of adopting the "110" mining method for outburst coal seam groups, when using the "110" method to cut the roof and retain the roadway before the formation of Y-shaped ventilation or W-shaped ventilation, a perfect return air system cannot be formed in the retained roadway section, resulting in problems such as the inability to monitor the surrounding rock changes in the retained roadway section, the accumulation of toxic and harmful gases in the retained roadway section, and the inability to drill in the retained roadway section for gas control. It will also increase the economic cost of coal mine mining.

[0040] To solve the above technical problems, as Figure 5 and 6 shown, the embodiment of the present application provides a three-dimensional ventilation method and system for multi-seam mining in a coal and gas outburst mine, which is applied to a mining area with multiple coal seams, especially a mining area with multiple coal and gas outburst coal seams, that is, the coal mining area is an outburst coal seam group containing several coal and gas outburst coal seams, to solve the above technical problems of the present invention. The outburst coal seam group at least includes a first coal seam, a second coal seam, and a third coal seam arranged in sequence. The ventilation system of the coal mining area includes an intake airway main roadway 1 and a return airway main roadway 2 serving each coal seam. A certain coal mining face in the first coal seam is defined as the first working face 3, a certain coal mining face in the second coal seam is defined as the second working face 4, and a certain coal mining face in the third coal seam is defined as the third working face 5. The gateways on both sides of the first working face 3 are respectively defined as the first track gateway 6 and the first transportation gateway 7, the gateways on both sides of the second working face 4 are respectively defined as the second track gateway 8 and the second transportation gateway 9, and the gateways on both sides of the third working face 5 are respectively defined as the third track gateway 10 and the third transportation gateway 11.

[0041] The three-dimensional ventilation method for multi-seam mining in a coal and gas outburst mine includes:

[0042] The second working face 4 has a second track gateway 8 and a second transportation gateway 9. The second track gateway 8 forms a first retained roadway 12 through the roof cutting and pressure relief roadway retaining process, and the second transportation gateway 9 forms a second retained roadway 13 through the roof cutting and pressure relief roadway retaining process. The cut-through of the second working face 4 is retained through the roof cutting and pressure relief roadway retaining process to form a third retained roadway 14. Gas drainage and outburst elimination can be realized for the adjacent unmined first coal seam through the first retained roadway 12, the second retained roadway 13, and the third retained roadway 14. The first end of the second retained roadway 13 is connected to the intake airway main roadway 1, the first end of the first retained roadway 12 is connected to the return airway main roadway 2, and the third retained roadway 14 is used to connect the first retained roadway 12 and the second retained roadway 13, that is, the second end of the second retained roadway 13 is connected to the second end of the first retained roadway 12 through the third retained roadway 14;

[0043] Before the first working face 3 in the first coal seam is mined, the first track gateway 6 and the first conveyor gateway 7 on both sides of the first working face 3 are constructed. Both the first track gateway 6 and the first conveyor gateway 7 are connected to the main intake airway 1, and the first ventilation roadway 15 and the second ventilation roadway 16 are constructed. One end of the first ventilation roadway 15 is connected to the end of the first track gateway 6 far from the main intake airway 1, the other end of the first ventilation roadway 15 is connected to the first retained roadway 12, one end of the second ventilation roadway 16 is connected to the end of the first conveyor gateway 7 far from the main intake airway 1, and the other end of the second ventilation roadway 16 is connected to the second retained roadway 13;

[0044] During the mining of the first working face 3 in the first coal seam, the part of the first track gateway 6 located in the goaf forms the fourth retained roadway 17 along with the mining, and the part of the first conveyor gateway 7 located in the goaf forms the fifth retained roadway 18 along with the mining. The intake air of the fourth retained roadway 17 enters the first retained roadway 12 in the second coal seam through the first ventilation roadway 15 to form return air, and the intake air of the fifth retained roadway 18 enters the second retained roadway 13 in the second coal seam through the second ventilation roadway 16 to form return air.

[0045] The three-dimensional ventilation method provided in the above embodiments is applied to outburst coal seam groups, and the first retained roadway 12, the second retained roadway 13 and the third retained roadway 14 in adjacent coal seams can be fully utilized to construct a three-dimensional ventilation system. While realizing the ventilation of the retained roadway sections of the working faces in each coal seam, the retained roadway sections can be monitored in real time and the accumulation of harmful gases in the retained roadway sections can be eliminated, reducing safety hazards such as personnel poisoning and gas explosion.

[0046] As Figure 6 shown, the ventilation route in the three-dimensional ventilation system shown in the figure is as follows: The air enters through the second retained roadway 13, the first conveyor gateway 7 and the first track gateway 6, and the return air is discharged through the first retained roadway 12. A part of the intake air of the first conveyor gateway 7 is diverted to the coal mining face of the first working face 3 in the first coal seam (hereinafter defined as the first coal mining face 19) and then converges with the intake air of the first track gateway 6, and then successively passes through the fourth retained roadway 17 and the first ventilation roadway 15 and then enters the first retained roadway 12 to form return air; Another part of the intake air of the first conveyor gateway 7 is diverted to the fifth retained roadway 18, and then converges with the intake air of the second retained roadway 13 through the second ventilation roadway 16, and then enters the first retained roadway 12 through the third retained roadway 14 to form return air. That is, it will at least include the following ventilation sub-routes:

[0047] (1) Fresh air flow → Main intake airway 1 → First track gateway 6 → Fourth retained roadway 17 → First ventilation roadway 15 → First retained roadway 12 → Return airway 2;

[0048] (2) Fresh air current → Intake main roadway 1 → First haulage gateway 7 → First coal mining face 19 → Fourth retained roadway 17 → First ventilation roadway 15 → First retained roadway 12 → Return airway 2;

[0049] (3) Fresh air current → Intake main roadway 1 → First haulage gateway 7 → Fifth retained roadway 18 → Second ventilation roadway 16 → Third retained roadway 14 → First retained roadway 12 → Return airway 2;

[0050] (4) Fresh air current → Intake main roadway 1 → Second retained roadway 13 → Third retained roadway 14 → First retained roadway 12 → Return airway 2.

[0051] Figure 5 and 6 In the three-dimensional ventilation system shown in

[0052] and its corresponding three-dimensional ventilation method, after the coal mining of the working face in the first coal seam is completed, the part of the first track gateway 6 located in the goaf forms the fourth retained roadway 17, and the part of the first haulage gateway 7 located in the goaf forms the fifth retained roadway 18. The next coal mining face can be arranged on one side of the first haulage gateway 7 and one side of the first track gateway 6. Both the fourth retained roadway 17 and the fifth retained roadway 18 can be used as gateways for the next coal mining face. Figure 7 and 8 shown, the outburst coal seam group further includes a third coal seam adjacent to the second coal seam, that is, the first coal seam and the third coal seam are respectively located on both sides of the second coal seam.

[0053] At this time, the three-dimensional ventilation method for multi-seam mining in a coal and gas outburst mine further includes:

[0054] The second working face 4 has a second track gateway 8 and a second haulage gateway 9. The second track gateway 8 forms the first retained roadway 12 through the roof cutting and pressure relief retaining roadway technology, the second haulage gateway 9 forms the second retained roadway 13 through the roof cutting and pressure relief retaining roadway technology, and the cut-through of the second working face 4 is retained through the roof cutting and pressure relief retaining roadway technology to form the third retained roadway 14. Gas drainage and outburst elimination of the adjacent unmined third coal seam can be realized through the first retained roadway 12, the second retained roadway 13 and the third retained roadway 14. The first end of the second retained roadway 13 is connected to the intake main roadway 1, the first end of the first retained roadway 12 is connected to the return airway 2, and the third retained roadway 14 is used to connect the first retained roadway 12 and the second retained roadway 13, that is, the second end of the second retained roadway 13 is connected to the second end of the first retained roadway 12 through the third retained roadway 14;

[0055] Before the mining of the third working face 5 in the third coal seam, the third track gateway 10 and the third conveyor gateway 11 on both sides of the third working face 5 are constructed. Both the third track gateway 10 and the third conveyor gateway 11 are connected to the main intake airway 1, and the third ventilation roadway 20 and the fourth ventilation roadway 21 are constructed. One end of the third ventilation roadway 20 is connected to the end of the third track gateway 10 far from the main intake airway 1, the other end of the third ventilation roadway 20 is connected to the first retained roadway 12, one end of the fourth ventilation roadway 21 is connected to the end of the third conveyor gateway 11 far from the main intake airway 1, and the other end of the fourth ventilation roadway 21 is connected to the second retained roadway 13;

[0056] During the mining of the third working face 5 in the third coal seam, the part of the third track gateway 10 located in the goaf forms the sixth retained roadway 22 along with the mining, and the part of the third conveyor gateway 11 located in the goaf forms the seventh retained roadway 23 along with the mining. The intake air of the sixth retained roadway 22 enters the first retained roadway 12 in the second coal seam through the third ventilation roadway 20 to form return air, and the intake air of the seventh retained roadway 23 enters the second retained roadway 13 in the second coal seam through the fourth ventilation roadway 21 to form return air.

[0057] The three-dimensional ventilation method provided in the above embodiment is applied to outburst coal seam groups. The third coal seam can make full use of the first retained roadway 12, the second retained roadway 13 and the third retained roadway 14 in the adjacent second coal seam to construct a three-dimensional ventilation system. While realizing the ventilation of the retained roadway sections in each coal seam, the retained roadway sections can be monitored in real time and the accumulation of harmful gases in the retained roadway sections can be eliminated, reducing safety hazards such as personnel poisoning and gas explosion.

[0058] As Figure 8 shown, the ventilation route in the three-dimensional ventilation system shown in the figure is as follows: the intake air passes through the second retained roadway 13, the third conveyor gateway 11 and the third track gateway 10, and the return air passes through the first retained roadway 12. A part of the intake air of the third conveyor gateway 11 is diverted to the coal mining face of the third working face 5 in the third coal seam (hereinafter defined as the third coal mining face 24) and then converges with the intake air of the third track gateway 10, and then successively passes through the sixth retained roadway 22 and the third ventilation roadway 20 and then enters the first retained roadway 12 to form return air; another part of the intake air of the third conveyor gateway 11 is diverted to the seventh retained roadway 23, and then converges with the intake air of the second retained roadway 13 through the fourth ventilation roadway 21, and then passes through the third retained roadway 14 and enters the first retained roadway 12 to form return air. That is, it will at least include the following ventilation sub-routes:

[0059] (1) Fresh air flow → Main intake airway 1 → Third track gateway 10 → Sixth retained roadway 22 → Third ventilation roadway 20 → First retained roadway 12 → Return airway 2;

[0060] (2) Fresh air flow → Intake main roadway 1 → Third haulage gateway 11 → Third coal mining face 24 → Sixth retained roadway 22 → Third ventilation roadway 20 → First retained roadway 12 → Return air main roadway 2;

[0061] (3) Fresh air flow → Intake main roadway 1 → Third haulage gateway 11 → Seventh retained roadway 23 → Fourth ventilation roadway 21 → Third retained roadway 14 → First retained roadway 12 → Return air main roadway 2;

[0062] (4) Fresh air flow → Intake main roadway 1 → Second retained roadway 13 → Third retained roadway 14 → First retained roadway 12 → Return air main roadway 2.

[0063] Figure 7 and 8 In the three-dimensional ventilation system shown in

[0064] and its corresponding three-dimensional ventilation method, after the third working face 5 in the third coal seam is mined out, the part of the third track gateway 10 located in the goaf forms the sixth retained roadway 22, and the part of the third haulage gateway 11 located in the goaf forms the seventh retained roadway 23. The next coal mining face can be arranged on one side of the third haulage gateway 11 and one side of the third track gateway 10. Both the sixth retained roadway 22 and the seventh retained roadway 23 can be used as the gateways of the next coal mining face.

[0065] In the above embodiment, after the first working face 3 in the first coal seam is mined out, the fourth retained roadway 17 and the fifth retained roadway 18 formed by retaining the first haulage gateway 7 and the first track gateway 6 through the roof cutting and pressure relief retaining roadway technology can be used for gas drainage and outburst elimination of the unmined coal seams adjacent to the first coal seam. And by continuously constructing the cross-seam ventilation roadway, the fourth retained roadway 17 and the fifth retained roadway 18 can form a three-dimensional ventilation system with the gateways of the unmined coal seams adjacent to the first coal seam through the ventilation roadway, and the ventilation of all the coal seams of the outburst coal seam group located on the side of the first coal seam where the second coal seam is set is completed in sequence by the aforementioned method until a three-dimensional ventilation system is formed between all the coal seams above the second coal seam; Similarly, after the third working face 5 in the third coal seam is mined out, the sixth retained roadway 22 and the seventh retained roadway 23 formed by retaining the third haulage gateway 11 and the third track gateway 10 through the roof cutting and pressure relief retaining roadway technology can be used for gas drainage and outburst elimination of the unmined coal seams adjacent to the third coal seam. And by continuously constructing the cross-seam ventilation roadway, the sixth retained roadway 22 and the seventh retained roadway 23 can form a three-dimensional ventilation system with the gateways of the unmined coal seams adjacent to the third coal seam through the ventilation roadway, and the ventilation of all the coal seams of the outburst coal seam group located on the side of the third coal seam where the second coal seam is set is completed in sequence by the aforementioned method until a three-dimensional ventilation system is formed between all the coal seams below the second coal seam.

[0065] It should be noted that in the above embodiments, the second coal seam can be the first mined coal seam of the outburst multi - coal seam group, or it can be a non - first - mined coal seam. The second coal seam can be the coal seam being mined in the outburst multi - coal seam group or the coal seam that has been mined. As long as it can form a three - dimensional ventilation system with adjacent coal seams by forming a crossheading or retaining a roadway. The working face in the second coal seam can be the working face during the coal mining process in the second coal seam or the working face that has completed coal mining.

[0066] Preferably, the second working face 4 in the second coal seam is the first mined working face of the outburst coal seam group. As Figure 4 shown, during the coal mining process of the second working face 4 in the second coal seam, the part of the second transportation crossheading 9 located in the goaf forms the second retained roadway 13, the part of the second track crossheading 8 located in the goaf forms the first retained roadway 12, and the cut - eye of the second working face 4 forms the third retained roadway 14. During the coal mining process of the second working face 4, the intake main roadway 1, the return air main roadway 2, the second transportation crossheading 9, the second track crossheading 8, the coal mining working face of the second working face 4 in the second coal seam (hereinafter defined as the second coal mining working face 25), the first retained roadway 12, the second retained roadway 13, and the third retained roadway 14 form a double - U ventilation system to realize the ventilation of the first retained roadway 12 and the second retained roadway 13 sections. Of course, when the working face in the second coal seam is the first mined working face of the outburst coal seam group, it can also drive a gas drainage roadway in the rock roadway to achieve a perfect three - dimensional ventilation with the crossheadings on both sides of the second working face 4. However, this usually requires driving a rock roadway between coal seams and has many adverse effects.

[0067] Specifically, when this method is applied to the mining of outburst coal seam groups, when it is necessary to select a middle coal seam as the protective layer for mining according to the gas parameters and mining technical conditions of the coal seam group, this protective layer is the second coal seam. The first mined working face of the second coal seam (i.e., the second working face 4 in the second coal seam exemplified in this application) can use long boreholes along the seam to pre - extract strip gas for outburst elimination; then, using the technology of roof - cutting pressure - relief and non - pillar roadway self - formation, the cut - eye and two crossheadings of the first mined working face are left to form a double - U ventilation; finally, the adjacent coal seams are connected to the crossheading retained roadways through the first ventilation roadway 15 and the second ventilation roadway 16, and this layout method is cycled to complete the layout of the ventilation circuit for the entire mining area.

[0068] When the second coal seam is the protective layer and the second working face 4 in the second coal seam is selected as the first mined working face, the three - dimensional ventilation method for the outburst coal seam group can be realized through the following steps 1 - 4.

[0069] Step 1: Arrange the first mining face in the second coal seam, i.e., the second working face 4. Using the roof cutting and pressure relief roadway retaining technology, simultaneously construct roof cutting and roadway retaining in the second track gateway 8, the second transportation gateway 9, and the cut-through of the second working face 4 to form the first roadway retaining 12, the second roadway retaining 13, and the third roadway retaining 14 respectively, forming a double U-shaped ventilation system as shown in Figure 4 The specific ventilation route is as follows:

[0070] (1) Fresh air flow → intake main roadway 1 → second transportation gateway 9 → second roadway retaining 13 → third roadway retaining 14 → first roadway retaining 12 → second track gateway 8 → return air main roadway 2.

[0071] (2) Fresh air flow → intake main roadway 1 → second transportation gateway 9 → second coal mining face 25 → second track gateway 8 → return air main roadway 2.

[0072] Step 2: As shown in Figure 6 After the second working face 4 has completed mining, arrange the upper coal seam mining face, i.e., the first mining face in the first coal seam, which can refer to the first working face 3. Arrange the first ventilation roadway 15 to connect the first track gateway 6 and the first roadway retaining 12; arrange the second ventilation roadway 16 to connect the first transportation gateway 7 and the second roadway retaining 13; then simultaneously construct roof cutting and roadway retaining in the first track gateway 6 and the first transportation gateway 7 to form the fourth roadway retaining 17 and the fifth roadway retaining 18 respectively, forming a complete ventilation circuit. The specific ventilation route is as shown in the figure.

[0073] Step 3: As shown in Figure 8 After the working face in the second coal seam has completed mining, arrange the lower adjacent coal seam mining face, i.e., the first mining face in the third coal seam, which can refer to the third working face 5. Arrange the third ventilation roadway 20 to connect the third track gateway 10 and the first roadway retaining 12; arrange the fourth ventilation roadway 21 to connect the third transportation gateway 11 and the second roadway retaining 13; then simultaneously construct roof cutting and roadway retaining in the third track gateway 10 and the third transportation gateway 11 to form the sixth roadway retaining 22 and the seventh roadway retaining 23 respectively, forming a complete ventilation circuit. The specific ventilation route is as shown in the figure.

[0074] Step 4: After each working face has completed mining, use the methods of Step 2 and Step 3 to develop upward and downward respectively to complete the establishment of the ventilation system for the entire mining area and complete the mining. The construction sequence of Step 2 and Step 3 is not in order, and either one can be constructed separately or both can be constructed simultaneously according to the actual production system layout of the coal mine.

[0075] In addition, in Steps 2 and 3 above, the first working face 3 in the first coal seam and the second working face 4 in the second coal seam can be mined simultaneously without waiting for the mining and roadway retaining of the second working face 4 in the second coal seam to be completed entirely. This can also form a perfect ventilation system and achieve efficient mining. Similarly, the third working face 5 in the third coal seam and the second working face 4 in the second coal seam can be mined simultaneously without waiting for the mining and roadway retaining of the second working face 4 in the second coal seam to be completed entirely.

[0076] It should be noted that the first working face 3 in the first coal seam, the second working face 4 in the second coal seam, and the third working face 5 in the third coal seam listed in the embodiments of the present invention can be the first mining working face in the corresponding coal seam or a non-first mining working face in the corresponding coal seam. After the ventilation and mining of one working face in any coal seam are completed, the entire coal seam can be mined by developing towards both sides centered on this working face. During the process of developing towards both sides, the ventilation of subsequent working faces in the same coal seam can be completed through traditional ventilation methods, or the ventilation of subsequent working faces can be completed by relying on the roadway retaining in adjacent coal seams.

[0077] The three-dimensional ventilation method for outburst coal seam group mining in the above embodiments of the present invention has the following technical advantages:

[0078] (1) A perfect ventilation system is formed in the roadway retaining section. After the three-dimensional ventilation is implemented in the roadway retaining section, a perfect ventilation system is formed, and the toxic and harmful gases in the goaf and adjacent coal seams no longer accumulate, reducing safety hazards such as personnel poisoning and gas explosion.

[0079] (2) The initial tunneling workload is reduced. After the roof cutting and pressure relief non-pillar self-forming roadway technology is used to retain the roadway for the working face cut-through and two gateways, a double U-shaped ventilation system is formed. When arranging the first mining working face of the protective seam, there is no need for three sides and four roadways, reducing the initial tunneling workload and improving the normal production efficiency of the coal mine.

[0080] (3) Realize three-dimensional ventilation of adjacent coal seams. After the mining of a certain working face in a coal seam is completed, the adjacent coal seam is connected to the previously retained roadway through ventilation to form cross-coal seam three-dimensional ventilation, which is convenient for controlling the air volume and air flow in the entire mining area. At the same time, the remaining roadway is used to continue the gas drainage of the upper coal seam or the lower coal seam, avoiding the easy gas overlimit when the mining speed of the upper coal seam or the lower coal seam is fast, and also realizing safe and efficient mining.

[0081] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A three-dimensional ventilation method for multi-seam mining in a coal and gas outburst mine, characterized in that The coal mining area of the mine is a outburst coal seam group containing several coal seams. The outburst coal seam group includes a first coal seam and a second coal seam arranged adjacent to each other, where: The second working face (4) located in the second coal seam has a second track gateway (8) and a second transportation gateway (9). The second track gateway (8) is retained by the roof cutting pressure relief and roadway retaining technology to form a first retained roadway (12), the second transportation gateway (9) is retained by the roof cutting pressure relief and roadway retaining technology to form a second retained roadway (13), and the cut-through of the second working face (4) is retained by the roof cutting pressure relief and roadway retaining technology to form a third retained roadway (14); Before the first working face (3) in the first coal seam is mined, the first track gateway (6) and the first transportation gateway (7) on both sides of the first working face (3) are constructed, and the first ventilation roadway (15) and the second ventilation roadway (16) are constructed. The two ends of the first ventilation roadway (15) are respectively connected to the first retained roadway (12) and the first track gateway (6), and the two ends of the second ventilation roadway (16) are connected to the second retained roadway (13) and the first transportation gateway (7); During the mining process of the first working face (3), the first track gateway (6) forms a fourth retained roadway (17) along with the mining, and the first transportation gateway (7) forms a fifth retained roadway (18) along with the mining, so that the intake air of the fourth retained roadway (17) enters the first retained roadway (12) through the first ventilation roadway (15) to form return air; The ventilation circuit of the outburst coal seam group includes: Intake air through the second retained roadway (13), the first transportation gateway (7) and the first track gateway (6), and return air through the first retained roadway (12); A part of the intake air of the first transportation gateway (7) is diverted to the coal mining working face of the first coal seam and then converges with the intake air of the first track gateway (6), and then enters the first retained roadway (12) through the fourth retained roadway (17) and the first ventilation roadway (15) in sequence to form return air; Another part of the intake air of the first transportation gateway (7) is diverted to the fifth retained roadway (18), then converges with the intake air of the second retained roadway (13) through the second ventilation roadway (16), and then enters the first retained roadway (12) through the third retained roadway (14) to form return air.

2. The three-dimensional ventilation method according to claim 1, characterized in that After the first working face (3) is mined, the fourth retained roadway (17) and the fifth retained roadway (18) are retained, and a three-dimensional ventilation system is formed with the working face gateways of the unmined coal seams adjacent to the first coal seam.

3. The three-dimensional ventilation method according to claim 1, characterized in that Both the fourth retained roadway (17) and the fifth retained roadway (18) are retained for use as the gateways of the unmined coal seams on both sides of the first working face (3).

4. The three-dimensional ventilation method according to claim 1, characterized in that The outburst coal seam group further includes a third coal seam arranged adjacent to the second coal seam. The first coal seam and the third coal seam are respectively located on the upper and lower sides of the second coal seam, and there is a third working face (5) in the third coal seam.

5. The three-dimensional ventilation method according to claim 4, wherein, Before the third working face (5) is mined, the third track gateway (10) and the third transportation gateway (11) on both sides of the third working face (5) are constructed, and the third ventilation roadway (20) and the fourth ventilation roadway (21) are constructed. The two ends of the third ventilation roadway (20) are respectively connected to the first retained roadway (12) and the third track gateway (10), and the two ends of the fourth ventilation roadway (21) are connected to the second retained roadway (13) and the third transportation gateway (11).

6. The three-dimensional ventilation method according to claim 5, characterized in that, After the third working face (5) is mined, the third transportation gateway (11) and the third track gateway (10) are retained by the roof cutting and pressure relief roadway retaining technology, and a three-dimensional ventilation system is formed with the working face gateways of the unmined coal seams adjacent to the third coal seam.

7. The three-dimensional ventilation method according to any one of claims 1-6, characterized in that After the ventilation and mining of a working face are completed in any coal seam, the entire coal seam is mined by developing towards both sides with this working face as the center.

8. A three-dimensional ventilation system for multi-seam mining in a coal and gas outburst mine, characterized in that, Formed by the three-dimensional ventilation method of the coal and gas outburst mine according to any one of claims 1-7.

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