Three-dimensional gas extraction method for close distance outburst coal seam group

Abstract

The application relates to the technical field of gas extraction, in particular to a three-dimensional gas extraction method for close-distance outburst coal seams. The method carries out gas extraction and outburst elimination on adjacent working faces and their crossheading through directional long boreholes, cancels the gas extraction roadway of the crossheading of the adjacent stoping working face and the crossheading of the stoping working face of the adjacent seam, and solves the problem of mining and excavation disorder caused by long gas treatment time of the coal and gas outburst mine. Except that the gas extraction roadway needs to be constructed in the first stoping working face of the protective layer, the long boreholes along the layer are left in the crossheading formed by the gob-side entry retaining to eliminate the outburst of the gas and strip gas of the stoping working face, the gas extraction roadway of the rest working faces is cancelled, the roadway excavation engineering is reduced, and the problem of tight mining and excavation replacement is solved.

Description

Technical Field

[0001] This application relates to the field of gas extraction technology, specifically to a three-dimensional gas extraction method for a nearby outburst coal seam group. Background Technology

[0002] With the increasing intensity and depth of coal resource mining, the threat of coal and gas outbursts to coal mine safety will become increasingly serious. When mining coal seams with close proximity to outbursts, deploying gas drainage roadways in the roof (or floor) strata of the coal seam, and pre-draining coal seam gas through dense cross-strata drilling and long boreholes along the coal seam in the pre-drainage roadways is one of the main regional outburst prevention measures. However, constructing gas drainage roadways and drilling in the roof (or floor) strata of the coal seam involves a large amount of work, is difficult to control the strata, poses significant safety risks during tunneling, has a long construction time, and results in high economic costs for coal production, leading to imbalances in coal mine operations. Currently, the technology of roof cutting and pressure relief without coal pillars to form self-contained roadways involves reinforcing and supporting the mining roadways, then performing directional pre-splitting blasting on the side of the roadway where a goaf will form. The roof is then cut at the designed location. After the cutting is completed, as the coal seam is mined, under mine pressure, the roof of the goaf collapses along the pre-splitting cuts to form a roadway sidewall. A new roadway is automatically formed using part of the original roadway space and support, serving as the mining roadway for the next working face. Each mining face no longer requires two coal roadways and two gas drainage roadways, but only one coal roadway and one gas drainage roadway. Although only one gas drainage roadway is constructed per mining face, many coal mines still face numerous problems such as long construction time for gas drainage roadways and large-scale gas control projects, leading to mining imbalances and low economic efficiency.

[0003] Although the current top-cutting and roadway-retention technology only requires the construction of one gas drainage roadway per longwall face to manage gas, reducing the workload by half compared to the past, the following problems still exist:

[0004] The gas extraction roadway is located in the rock, which makes the tunneling speed slow, the drilling construction difficult, and the tunneling time long. The tunneling progress is far lower than the mining progress, resulting in a mining imbalance.

[0005] The drilling distance for cross-seam extraction in gas drainage roadways is long and requires passing through the coal seam itself. The drilling time is long, the sealing effect is poor, and the time for gas control is increased.

[0006] After the gas extraction roadway and borehole construction are completed, gas extraction needs to be carried out on the longwall face and tunneling roadway. Construction can only proceed after the gas pressure or content meets the relevant safety requirements. The "mining", "tunneling" and "extraction" cannot be carried out simultaneously, which seriously affects production efficiency. Summary of the Invention

[0007] To address the aforementioned technical problems, this application provides the following technical solutions.

[0008] This application provides a three-dimensional gas extraction method for near-field outburst coal seam groups, which includes the following steps:

[0009] In the outburst coal seam group, a protective layer is identified. The coal seams on one side of the protective layer are named in ascending order of odd numbers, starting from coal seam No. 1, in the direction away from the protective layer. The coal seams on the other side of the protective layer are named in ascending order of even numbers, starting from coal seam No. 2. Each coal seam has a first mining face. The longwall faces on one side of the first mining face are named in ascending order of odd numbers, starting from longwall face No. 1, in the direction away from the first mining face. The longwall faces on the other side of the first mining face are named in ascending order of even numbers, starting from longwall face No. 2.

[0010] The location of the first mining face and its two roadways is determined in the protective layer. Two gas drainage roadways corresponding to the two roadways of the first mining face are set in the rock strata adjacent to the protective layer. The two gas drainage roadways are used to extract the strip gas in the area of ​​the two roadways of the first mining face of the protective layer.

[0011] Two roadways are formed on both sides of the first mining face of the protective layer, and the gas in the area of ​​the first mining face is extracted using the roadways of the first mining face. The two gas extraction roadways are connected by a connecting roadway. During the mining process of the first mining operation, the two roadways are left along the goaf. The two left roadway sections are connected to their corresponding gas extraction roadways by a connecting roadway to form a complete ventilation system.

[0012] Using the first mining face of the protective layer, long boreholes are drilled along the layer to pre-drain the gas in the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area.

[0013] After the gas control of the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area meets the standards, the roadway of the No. 1 longwall face and / or the roadway of the No. 2 longwall face will be constructed to form the No. 1 longwall face and / or the No. 2 longwall face.

[0014] Furthermore, by constructing cross-layer drainage boreholes in the roadway and gas drainage roadway of the first mining face of the protective layer to pre-drain the strip gas of coal seam No. 1 and / or coal seam No. 2, and constructing two roadways of coal seam No. 1 and / or coal seam No. 2 in the area where strip gas treatment meets the standards, thus forming the first mining face of coal seam No. 1 and / or coal seam No. 2. The roadway of the first mining face is used to extract gas in the area of ​​the first mining face. During the mining process of the first mining face, the two roadways are left along the goaf. The two left roadway sections are connected to the gas drainage roadway or the two roadways of the first mining face of the protective layer through connecting roadways to form a complete ventilation system.

[0015] Furthermore, the gas strips of the No. 2n+1 coal seam are pre-extracted by using the cross-layer extraction boreholes constructed in the roadway of the first mining face of the No. 2n-1 coal seam, and / or the gas strips of the No. 2n+2 coal seam are pre-extracted by using the cross-layer extraction boreholes constructed in the roadway of the first mining face of the No. 2n coal seam, where n is a positive integer.

[0016] In areas where strip gas control meets standards, construct two roadways for coal seam 2n+1 and / or two roadways for coal seam 2n+2 to form the first mining face for coal seam 2n+1 and / or coal seam 2n+2. Utilize the roadways of the first mining face to extract gas from the area within the first mining face. During the retreat mining process of the first mining operation, implement goaf retention roadways for the two roadways. The retained roadway sections are connected to the two roadways of the first mining face of the adjacent coal seam through connecting roadways to form a complete ventilation system.

[0017] Furthermore, in each coal seam, long boreholes are drilled along the seam using the first mining face roadway of the coal seam to pre-drain the gas from the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area.

[0018] After the gas control of the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area meets the standards, the roadway of the No. 1 longwall face and / or the roadway of the No. 2 longwall face will be constructed to form the No. 1 longwall face and / or the No. 2 longwall face.

[0019] Furthermore, in any coal seam, the gas of the No. 2n+1 longwall face and its roadway area is pre-extracted using the longwall borehole constructed in the roadway of the No. 2n-1 longwall face, and / or the gas of the No. 2n+2 longwall face and its roadway area is pre-extracted using the longwall borehole constructed in the roadway of the No. 2n longwall face, where n is a positive integer. The same method is followed until the gas extraction of the entire coal seam is completed.

[0020] Furthermore, the gas extraction roadway is either a top extraction roadway located in the rock stratum above the protective layer or a bottom extraction roadway located in the rock stratum below the protective layer.

[0021] The technical solution provided in this application proposes a three-dimensional gas extraction method for closely spaced outburst-prone coal seams using top-cutting and roadway retention. This method utilizes directional long boreholes to extract gas from adjacent working faces and their roadways, eliminating gas extraction roadways in adjacent longwall mining faces and near-coal seam longwall mining faces. This solves the problem of long gas control times leading to mining imbalances in coal and gas outburst mines. Compared to existing technologies, it offers the following technical advantages:

[0022] (1) Except for the first mining face of the protective layer, which requires the construction of a gas drainage roadway, the other working faces are all drained by the construction of long boreholes along the goaf to pre-drain the gas and strip gas of the mining face and eliminate the gas outburst. The gas drainage roadways of the other working faces are eliminated, the roadway excavation work is reduced, and the problem of tight mining and excavation succession is solved.

[0023] (2) By drilling through the adjacent coal seam through the goaf roadway to pre-extract the strip gas of the adjacent coal seam, the distance from the gas extraction roadway to the drilling through the gas extraction hole is shortened, the drilling time is reduced, the sealing effect is better, and the time for gas control at the working face is reduced.

[0024] (3) Gas control projects can be carried out on adjacent working faces while the working face is being mined. Gas control projects can be arranged in a coordinated manner, and a balance between "mining", "excavation" and "extraction" can be achieved in production. There is no need to stop production and wait for gas extraction time, which reduces the overall cost of gas control. Attached Figure Description

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

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the roadway layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 1 of this application;

[0028] Figure 2 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 1 of this application. Figure 1 ;

[0029] Figure 3 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 1 of this application. Figure 2 ;

[0030] Figure 4 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 1 of this application. Figure 3 ;

[0031] Figure 5 This is a cross-sectional view of the borehole plan layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 1 of this application;

[0032] Figure 6 This is a schematic diagram of the roadway layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 2 of this application;

[0033] Figure 7 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 2 of this application. Figure 1 ;

[0034] Figure 8 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 2 of this application. Figure 2 ;

[0035] Figure 9 This is a schematic diagram of the borehole layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 2 of this application. Figure 3 ;

[0036] Figure 10 This is a cross-sectional view of the borehole plan layout for the three-dimensional gas extraction method for near-field outburst coal seam groups in Embodiment 2 of this application.

[0037] In the picture:

[0038] 100. Intake airway; 200. Return airway;

[0039] 300. Protective layer; 301. First mining face; 302. Track roadway; 303. Transport roadway; 304. First retaining roadway; 305. Second retaining roadway; 306. No. 1 longwall face; 307. Track roadway; 308. No. 2 longwall face; 309. Transport roadway;

[0040] 400, No. 1 coal seam; 401, first mining face; 402, track roadway; 403, transport roadway; 404, No. 1 longwall face; 405, No. 2 longwall face;

[0041] 500, No. 2 coal seam; 501, first mining face; 502, track roadway; 503, transport roadway; 504, No. 1 longwall face; 505, No. 2 longwall face;

[0042] 601. Gas drainage intake airway; 602. Gas drainage return airway; 603. Connecting airway;

[0043] 701, First Connecting Lane; 702, Second Connecting Lane; 703, Third Connecting Lane; 704, Fourth Connecting Lane.

[0044] 800, in-seam long borehole; 900, cross-seam extraction borehole. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] As shown in the figure, this application provides a three-dimensional gas extraction method for a group of closely spaced outburst-prone coal seams. This method is applicable to mining areas with multiple coal seams, particularly those with multiple coal and gas outburst-prone seams, where the mining area is a group of closely spaced outburst-prone coal seams containing several coal and gas outburst-prone seams. The mining area includes an intake airway 100 and a return airway 200 serving each coal seam.

[0048] Example 1

[0049] like Figure 1-5 As shown, the three-dimensional gas extraction method for closely spaced outburst coal seam groups includes the following steps.

[0050] Step 1: Determine a protective layer 300 in multiple coal seams of the outburst coal seam group. The protective layer 300 is preferably a coal seam in the middle of the outburst coal seam group, which is used to establish the first mining face in the seam, and can be developed upward and downward respectively.

[0051] The coal seams located on one side of the protective layer 300 are named sequentially from seam 1 (400) in ascending order, in the direction away from the protective layer 300, using odd numbers. The coal seams on the other side of the protective layer 300 are named sequentially from seam 2 (500) in ascending order, in the direction away from the protective layer 300, using even numbers. In this embodiment, the coal seams above the protective layer 300 are named sequentially from seam 1, seam 3, seam 5, ... in the direction away from the protective layer 300. In this embodiment, the coal seams below the protective layer 300 are named sequentially from seam 2, seam 4, seam 6, ... in the direction away from the protective layer 300.

[0052] Each coal seam has a primary mining face. The mining faces on one side of the primary mining face are named sequentially from the smallest to the largest, starting with mining face 1, in the direction away from the primary mining face, in the odd-numbered order. The naming method is as follows: XX coal seam No. 1 mining face, XX coal seam No. 3 mining face, XX coal seam No. 5 mining face, ... The mining faces on the other side of the primary mining face are named sequentially from the smallest to the largest, starting with mining face 2, in the direction away from the primary mining face, in the even-numbered order. The naming method is as follows: XX coal seam No. 2 mining face, XX coal seam No. 4 mining face, XX coal seam No. 6 mining face, ... More specifically, in this application document, the longwall faces located on the side of the track roadway of the first mining face in each coal seam are named successively as No. 1 longwall face, No. 3 longwall face, No. 5 longwall face, ..., and the longwall faces located on the side of the transport roadway of the first mining face in each coal seam are named successively as No. 2 longwall face, No. 4 longwall face, No. 6 longwall face, ...

[0053] Step Two: Determine the location of the first mining face 301 and its two roadways within the protective layer 300. In the rock strata adjacent to the protective layer 300, construct two gas drainage roadways corresponding to the two roadways of the first mining face. Utilize these two gas drainage roadways to extract strip gas from the area of ​​the two roadways of the first mining face 301 within the protective layer 300. Specifically, the gas drainage roadways are bottom drainage roadways located in the adjacent rock strata below the protective layer 300, meaning they are arranged on the bottom plate of the protective layer 300. Specifically, the two roadways of the first mining face 301 of the protective layer 300 include a transport roadway 303 and a track roadway 302. The gas drainage roadways include a gas drainage intake roadway 601 corresponding to the transport roadway 303 and a gas drainage return airway 602 corresponding to the track roadway 302. The gas drainage intake roadway 601 is used to construct a cross-layer drainage borehole 900 upward to extract strip gas from the area of ​​the transport roadway 303 of the first mining face 301 of the protective layer 300. The gas drainage return airway 602 is used to construct a cross-layer drainage borehole 900 upward to extract strip gas from the area of ​​the track roadway 302 of the first mining face 301 of the protective layer 300.

[0054] After the gas control in the roadway area of ​​the first mining face 301 of the protective layer 300 meets the standards, a transport roadway 303 and a track roadway 302 are formed on both sides of the first mining face 301 of the protective layer 300, and the gas in the area of ​​the first mining face 301 is extracted using the roadway of the first mining face 301 of the protective layer 300. The gas extraction intake airway 601 and the gas extraction return airway 602 are connected by a connecting roadway 603. The gas extraction intake airway 601 is connected to the intake airway 100, and the gas extraction return airway 602 is connected to the return airway 200. The track roadway 302 and the transport roadway 303 of the first mining face 301 are both connected to the intake airway 100. During the mining process of the first mining of the protective layer 300, the track roadway 302 and the transport roadway 303 are left along the goaf. The two left roadway sections are connected to their corresponding gas extraction airways through connecting roadways to form a complete ventilation system. Specifically, during the mining process of the first mining face 301 of the protective layer 300, the track roadway 302 forms a first retainer roadway 304 through a top-cutting and pressure-relief retainer process, and the transport roadway 303 of the first mining face 301 forms a second retainer roadway 305 through the same process. The track roadway 302 and its first retainer roadway 304 of the first mining face 301 are connected to the gas extraction return airway 602 through the first connecting roadway 701, and the transport roadway 303 and its second retainer roadway 305 of the first mining face 301 are connected to the gas extraction intake airway 601 through the second connecting roadway 702. The airflow path in the ventilation system formed is as follows: Figure 1 As shown.

[0055] The above-mentioned layout of the first mining face 301 does not leave coal pillars, thus reducing stress concentration. The first mining face 301 adopts the roof cutting and pressure relief coal pillar-free self-forming roadway process, retaining the two roadways of the first mining face 301, and using the gas drainage intake roadway 601 and the gas drainage return airway 602 to form a complete ventilation system.

[0056] Step 3: As Figure 2 and 3 As shown, a long borehole 800 is drilled along the roadway of the first mining face 301 using the protective layer 300 to pre-extract gas from the No. 1 long mining face 306 and its roadway area and / or the No. 2 long mining face 308 and its roadway area. Specifically, a long borehole 800 is drilled along the roadway 302 of the first mining face 301 to pre-extract gas from the No. 1 long mining face 306 and the strip gas in the track roadway 307 of the No. 1 long mining face 306; a long borehole 800 is drilled along the roadway 303 of the first mining face 301 to pre-extract gas from the No. 2 long mining face 308 and the strip gas in the transport roadway 309 area of ​​the No. 2 long mining face 308.

[0057] It should be noted that, due to the adoption of the top-cutting and roadway-retention technique, during the mining process, the roof of the goaf collapses along the pre-splitting joints to form roadway walls in the track roadway of the previous mining face. A new roadway is automatically formed using part of the original roadway space and support. The roadway retained from the track roadway of the previous mining face can be used as the transport roadway for the next adjacent mining face. Similarly, due to the adoption of the top-cutting and roadway-retention technique, during the mining process, the roof of the goaf collapses along the pre-splitting joints to form roadway walls in the transport roadway of the previous mining face. A new roadway is automatically formed using part of the original roadway space and support. The roadway retained from the transport roadway of the previous mining face can be used as the track roadway for the next adjacent mining face. Specifically, in this step, the first roadway 304 formed during the mining process of the track roadway 302 of the first mining face 301 of the protective layer 300 can be used as the transport roadway of the mining face 306 of the protective layer 3001; the second roadway 305 formed during the mining process of the transport roadway 303 of the first mining face 301 of the protective layer 300 can be used as the track roadway of the mining face 308 of the protective layer 3002. That is, the two roadways of the first mining face 301 can be used as roadways for adjacent working faces in the protective layer 300 coal seam without leaving coal pillars, eliminating stress concentration around the coal pillars of this coal seam and adjacent coal seams, reducing deformation of the mining roadway to the surrounding rock, and ensuring safe and efficient mine production.

[0058] At the same time, such as Figure 2-5As shown, the gas drainage roadway formed by the roadway of the first mining face 301 of the protective layer 300 can be used to construct the cross-layer drainage borehole 900 to pre-drain the strip gas of No. 1 coal seam 400 and / or No. 2 coal seam 500. In the area where the strip gas treatment meets the standards, two roadways of No. 1 coal seam 400 and / or two roadways of No. 2 coal seam 500 can be constructed to form the first mining face 401 of No. 1 coal seam 400 and / or the first mining face 501 of No. 2 coal seam 500. The gas in the area of ​​the first mining face can be extracted using the roadway of the first mining face. During the mining process of the first mining face, the two roadways are left along the goaf. The two roadway sections are connected to the gas drainage roadway or the two roadways of the first mining face 301 of the protective layer 300 through connecting roadways to form a complete ventilation system. Specifically, utilizing the first roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300, an upward cross-layer extraction borehole 900 is constructed to pre-extract the strip gas from the No. 1 coal seam 400, which corresponds to the track roadway 402 area of ​​the first mining face 401 of the No. 1 coal seam 400; utilizing the second roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300, an upward cross-layer extraction borehole 900 is constructed to pre-extract the strip gas from the No. 1 coal seam 400, which corresponds to the area of ​​the track roadway 402 of the first mining face 401 of the No. 1 coal seam 400. The transport roadway 403 area of ​​the first mining face 401 of coal seam 400; a cross-layer drainage borehole 900 is constructed downwards in the gas drainage intake airway 601 to pre-drain the strip gas of coal seam 500, which corresponds to the track roadway 502 area of ​​the first mining face 501 of coal seam 500; a cross-layer drainage borehole 900 is constructed downwards in the gas drainage return airway 602 to pre-drain the strip gas of coal seam 500, which corresponds to the transport roadway 503 area of ​​the first mining face 501 of coal seam 500.

[0059] In the above implementation method, the gas strip of No. 1 coal seam 400 is pre-extracted by constructing a cross-layer extraction borehole 900 upward through the goaf retention roadway formed by the protective layer 300 first mining face 301. Compared with the method of constructing the cross-layer extraction borehole 900 from the gas extraction roadway to No. 1 coal seam 400, the drilling distance is shortened, the drilling time is reduced, the sealing effect is better, and thus the gas control time of the working face is reduced.

[0060] Furthermore, the gas strips in the No. 2n+1 coal seam can be pre-extracted from the No. 400 coal seam through the cross-layer extraction borehole 900 in the roadway construction of the No. 2n-1 coal seam 400, and / or the gas strips in the No. 2n+2 coal seam 500 can be pre-extracted from the No. 2n+2 coal seam through the cross-layer extraction borehole 900 in the roadway construction of the No. 2n coal seam 400, where n is a positive integer. Specifically, through-seam extraction boreholes 900 can be constructed in the track roadway 402 and transport roadway 403 of the No. 1 coal seam 400 first mining face 401 to pre-extract the strip gas from the No. 3 coal seam. Similarly, through-seam extraction boreholes 900 can be constructed in the track roadway 502 and transport roadway 503 of the No. 2 coal seam 500 first mining face 501 to pre-extract the strip gas from the No. 4 coal seam. In this way, the extraction can be extended upwards and downwards to complete the extraction of strip gas from the roadway areas corresponding to the first mining faces in all coal seams, thus removing obstacles to the excavation of the roadways in the first mining faces of each coal seam.

[0061] Based on the above implementation methods, in some implementation methods, the track roadway and haulage roadway of coal seam 400 (2n+1) are constructed in areas where the strip gas control meets the standards, thereby forming the first mining face of coal seam 400 (2n+1). Gas is extracted from the area of ​​the first mining face of coal seam 400 (2n+1) using the roadway of the first mining face of coal seam 400 (2n+1). During the mining process of the first mining face of coal seam 400 (2n+1), roadways are left along the goaf of the track roadway and haulage roadway. The left-away roadways are connected to the track roadway and haulage roadway of the first mining face of the adjacent coal seam 400 (2n-1) through connecting roadways, forming... A complete ventilation system is implemented. In some embodiments, the track roadway and transport roadway of coal seam 2n+2 500 are constructed in the area where the strip gas control meets the standards, thereby forming the first mining face of coal seam 2n+2 500. The gas in the area of ​​the first mining face of coal seam 2n+2 500 is extracted using the roadway of the first mining face of coal seam 2n+2 500. During the mining process of the first mining face of coal seam 2n+2 500, roadway retention along the goaf is implemented. The roadway retention section is connected to the track roadway and transport roadway of the first mining face of the adjacent coal seam 2n through connecting roadways to form a complete ventilation system.

[0062] Step 4: In each coal seam, use the first mining face roadway of the coal seam to construct a long borehole 800 meters long along the seam to pre-drain the gas from the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area. After the gas control of the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area meets the standards, construct the roadway of the No. 1 mining face and / or the No. 2 mining face to form the No. 1 mining face and / or the No. 2 mining face. Then, the formed No. 1 mining face and / or the No. 2 mining face, which have completed the gas outburst elimination, can be mined, and the roadway along the goaf can be left open.

[0063] Taking protective layer 300 as an example, such as Figure 2 As shown, using the first retaining roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300, a long borehole 800 is constructed along the seam to pre-extract gas from the gas in the long mining face 306 of the protective layer 3001 and the strip gas in the track roadway 307 area of ​​the long mining face 306 of the protective layer 3001. After the gas in the long mining face 306 of the protective layer 3001 and the strip gas in the track roadway 307 area of ​​the long mining face 306 of the protective layer 3001 are treated to meet the standards, the track roadway 307 of the long mining face 306 of the protective layer 3001 is constructed. At this time, the first retaining roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300 is used as the transport roadway of the long mining face 306 of the protective layer 3001, thus forming the long mining face 306 of the protective layer 3001; on the other hand, as Figure 3 As shown, a long borehole 800 is constructed using the second retaining roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300. This is to pre-extract the gas from the No. 308 long mining face 300 of the protective layer 3002 and the strip gas in the transport roadway 309 area of ​​the No. 308 long mining face 3002. After the gas in the No. 308 long mining face 3002 and the strip gas in the transport roadway 309 area of ​​the No. 308 long mining face 3002 meet the standards, the transport roadway 309 of the No. 308 long mining face 3002 is constructed. At this time, the second retaining roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300 is used as the track roadway of the No. 308 long mining face 300, thus forming the No. 308 long mining face 300.

[0064] Taking No. 1 coal seam 400 as an example, the roadway formed by the track roadway 402 of the first mining face 401 of No. 1 coal seam 400 is used for construction of a long borehole 800 along the seam. This is used to pre-extract gas from the No. 1 long mining face 404 and the strip gas in the track roadway area of ​​the No. 1 long mining face 404. After the gas in the No. 1 long mining face 404 and the strip gas in the track roadway area of ​​the No. 1 long mining face 404 are treated to meet standards, the track roadway of the No. 1 long mining face 404 is constructed. At this time, the roadway formed by the track roadway 402 of the first mining face 401 of No. 1 coal seam 400 is used as the transport roadway of the No. 1 long mining face 404, thus forming the No. 1 long mining face 400. On the one hand, using the long borehole 800 formed by the transport roadway 403 of the first mining face 401 of No. 1 coal seam 400, the gas of the No. 1 coal seam 4002 long mining face 405 and the strip gas in the transport roadway area of ​​the No. 1 coal seam 4002 long mining face 405 are pre-extracted. After the gas in the No. 1 coal seam 4002 long mining face 405 and the strip gas in the transport roadway area of ​​the No. 1 coal seam 4002 long mining face 405 are treated to meet the standards, the transport roadway of the No. 1 coal seam 4002 long mining face 405 is constructed. At this time, the roadway formed by the transport roadway 403 of the first mining face 401 of No. 1 coal seam 400 is used as the track roadway of the No. 1 coal seam 4002 long mining face 405, thus forming the No. 1 coal seam 4002 long mining face 405.

[0065] Taking coal seam 500 as an example, a long borehole 800 is drilled along the seam using the roadway 502 formed by the track roadway 502 of the first mining face 501 of coal seam 500. This is used to pre-extract gas from the No. 2 coal seam 5001 longwall face 504 and the strip gas in the track roadway area of ​​the No. 2 coal seam 5001 longwall face 504. After the gas in the No. 2 coal seam 5001 longwall face 504 and the strip gas in the track roadway area of ​​the No. 2 coal seam 5001 longwall face 504 are treated to meet standards, the track roadway of the No. 2 coal seam 5001 longwall face 504 is constructed. At this time, the roadway 502 formed by the track roadway 502 of the first mining face 501 of coal seam 500 is used as the transport roadway of the No. 2 coal seam 5001 longwall face 504, thus forming the No. 2 coal seam 5001 longwall face. 504; On the other hand, using the roadway 503 formed by the transport roadway 503 of the first mining face 501 of No. 2 coal seam, a long borehole 800 is drilled along the seam to pre-extract the gas from the No. 2 coal seam No. 2 long mining face 505 and the strip gas in the transport roadway area of ​​the No. 2 coal seam No. 2 long mining face 505. After the gas in the No. 2 coal seam No. 2 long mining face 505 and the strip gas in the transport roadway area of ​​the No. 2 coal seam No. 2 long mining face 505 are treated to meet the standards, the transport roadway of the No. 2 coal seam No. 2 long mining face 505 is constructed. At this time, the roadway 503 formed by the transport roadway 503 of the first mining face 501 of No. 2 coal seam is used as the track roadway of the No. 2 coal seam No. 2 long mining face 505, thus forming the No. 2 coal seam No. 2 long mining face 505.

[0066] Furthermore, after the formation of either the No. 1 or No. 2 longwall face in any coal seam following the elimination of outbursts, the roadway formed during the mining process can be used to further eliminate outbursts in adjacent unmined faces. Specifically, in any coal seam, an 800mm longwall borehole can be drilled along the seam in the roadway of the No. 2n-1 longwall face to pre-drain the gas from the No. 2n+1 longwall face and its roadway area; alternatively, an 800mm longwall borehole can be drilled along the seam in the roadway of the No. 2n longwall face to pre-drain the gas from the No. 2n+2 longwall face and its roadway area, where n is a positive integer.

[0067] Taking protective layer 300 as an example, during or after the mining of protective layer 3001 mining face 306, the long borehole 800 formed by the roadway 307 of protective layer 3001 mining face 306 can be used to pre-drain the gas from protective layer 3003 mining face and the strip gas in the roadway area of ​​protective layer 3003 mining face 3003; during or after the mining of protective layer 3003 mining face 3003, the long borehole 800 formed by the roadway 3003 mining face 3005 mining face 3005 mining face 3005 mining face 3005 mining face 3005 can be used to pre-drain the gas from protective layer 3005 mining face ... Gas extraction; during or after the mining of the No. 3002 longwall face 308, the long borehole 800 formed by the haulage roadway 309 of the No. 3002 longwall face 308 can be used to pre-extract the gas from the No. 3004 longwall face 304 and the strip gas in the haulage roadway area of ​​the No. 3004 longwall face 3006 longwall face 3006 and the strip gas in the haulage roadway area of ​​the No. 3006 longwall face 3006 longwall face 3006. This process can be repeated to complete the gas extraction of all working faces on one side of the haulage roadway 303 of the first mining face 301 of the No. 300 protective layer.

[0068] Taking coal seam X as an example, during or after the mining of longwall face 1 in coal seam X, an 800mm long borehole formed by the track roadway of longwall face 1 in coal seam X can be used to pre-drain the gas from longwall face 3 in coal seam X and the strip gas in the track roadway area of ​​longwall face 3 in coal seam X; during or after the mining of longwall face 3 in coal seam X, an 800mm long borehole formed by the track roadway of longwall face 3 in coal seam X can be used to pre-drain the gas from longwall face 5 in coal seam X and the strip gas in the track roadway area of ​​longwall face 5 in coal seam X. This process can be repeated to complete the mining of all working faces on one side of the track roadway of coal seam X. Gas drainage: During or after the No. 2 longwall face of coal seam X, the 800mm longwall borehole formed by the haulage roadway of the No. 2 longwall face of coal seam X can be used to pre-drain the gas from the No. 4 longwall face of coal seam X and the strip gas in the haulage roadway area of ​​the No. 4 longwall face of coal seam X; During or after the No. 4 longwall face of coal seam X, the 800mm longwall borehole formed by the haulage roadway of the No. 4 longwall face of coal seam X can be used to pre-drain the gas from the No. 6 longwall face of coal seam X and the strip gas in the haulage roadway area of ​​the No. 6 longwall face of coal seam X. This process can be repeated to complete the gas drainage of all working faces on one side of the haulage roadway of coal seam X. Wherein, X represents a positive integer.

[0069] In this embodiment, a complete ventilation system is required for the construction of the first mining face in each coal seam. For the first mining face 301 of the protective layer 300, a connecting roadway connects the gas drainage roadway to the roadway sections of the two roadways of the first mining face of the protective layer 300. For other coal seams, connecting roadways connect the roadway sections of the two roadways of the first mining face of this coal seam to the roadway sections of the adjacent coal seam working faces. For the complete ventilation of other mining faces in each coal seam besides the first mining face, it can be accomplished by the traditional two-face three-roadway or three-face four-roadway method, or by connecting roadways that cross coal seams and connect to the roadways of adjacent coal seams. Those skilled in the art can choose the appropriate method as needed. In the embodiments of this application, a primary objective of forming a complete ventilation system is to enable ventilation of the roadway sections during mining. This allows for the pre-extraction of gas from adjacent coal seams via cross-seam extraction boreholes (900mm) and the extraction of gas from adjacent working faces within the same coal seam via longitudinal drilling (800mm). This allows for coordinated "mining" and "extraction." The remaining roadways can be used to extract gas from the upper or lower adjacent coal seams, enabling simultaneous gas extraction from the upper or lower adjacent coal seams and mining of the current coal seam's working face. The "mining" and "extraction" between upper and lower coal seams can be systematically coordinated, achieving upper and lower collaborative mining and resolving the issue of tight mining succession. The remaining roadways can also be used to drain gas from adjacent longwall faces in the same coal seam, allowing gas drainage from adjacent longwall faces to be carried out simultaneously with the mining of the current longwall face. The "mining" and "draining" between adjacent longwall faces can be carried out in a coordinated manner, enabling collaborative mining of multiple longwall faces within the coal seam and solving the problem of tight mining succession.

[0070] Example 2

[0071] like Figure 6-10 As shown, the three-dimensional gas extraction method for closely spaced outburst coal seam groups includes the following steps.

[0072] Step 1: Determine a protective layer 300 in multiple coal seams of the outburst coal seam group. The protective layer 300 is preferably a coal seam in the middle of the outburst coal seam group, which is used to establish the first mining face in the seam, and can be developed upward and downward respectively.

[0073] The coal seams located on one side of the protective layer 300 are named sequentially from coal seam 1 (400) in ascending order, in the direction away from the protective layer 300, using odd numbers. The coal seams on the other side of the protective layer 300 are named sequentially from coal seam 2 (500) in ascending order, in the direction away from the protective layer 300, using even numbers. In this embodiment, the coal seams above the protective layer 300 are named sequentially from coal seam 1 (400), coal seam 3, coal seam 5, ... in the direction away from the protective layer 300. In this embodiment, the coal seams below the protective layer 300 are named sequentially from coal seam 2 (500), coal seam 4, coal seam 6, ... in the direction away from the protective layer 300.

[0074] Each coal seam has a primary mining face. The mining faces on one side of the primary mining face are named sequentially from the smallest to the largest, starting with mining face 1, in the direction away from the primary mining face, in the odd-numbered order. The naming method is as follows: XX coal seam No. 1 mining face, XX coal seam No. 3 mining face, XX coal seam No. 5 mining face, ... The mining faces on the other side of the primary mining face are named sequentially from the smallest to the largest, starting with mining face 2, in the direction away from the primary mining face, in the even-numbered order. The naming method is as follows: XX coal seam No. 2 mining face, XX coal seam No. 4 mining face, XX coal seam No. 6 mining face, ... More specifically, in this application document, the longwall faces located on the side of the track roadway of the first mining face in each coal seam are named successively as No. 1 longwall face, No. 3 longwall face, No. 5 longwall face, ..., and the longwall faces located on the side of the transport roadway of the first mining face in each coal seam are named successively as No. 2 longwall face, No. 4 longwall face, No. 6 longwall face, ...

[0075] Step Two: As Figure 6 As shown, the positions of the first mining face 301 and its two roadways are determined within the protective layer 300. Two gas drainage roadways, corresponding to the two roadways of the first mining face, are constructed in the rock strata adjacent to the protective layer 300. These two gas drainage roadways are used to extract strip gas from the area of ​​the two roadways of the first mining face 301 within the protective layer 300. Specifically, the gas drainage roadways are top drainage roadways located in the adjacent rock strata above the protective layer 300, meaning they are arranged on the roof of the protective layer 300. Specifically, the two roadways of the first mining face 301 of the protective layer 300 include a transport roadway 303 and a track roadway 302. The gas drainage roadways include a gas drainage intake roadway 601 corresponding to the transport roadway 303 and a gas drainage return airway 602 corresponding to the track roadway 302. The gas drainage intake roadway 601 is used to construct a cross-layer drainage borehole 900 downward to extract strip gas from the area of ​​the transport roadway 303 of the first mining face 301 of the protective layer 300. The gas drainage return airway 602 is used to construct a cross-layer drainage borehole 900 downward to extract strip gas from the area of ​​the track roadway 302 of the first mining face 301 of the protective layer 300.

[0076] After the gas control in the roadway area of ​​the first mining face 301 of the protective layer 300 meets the standards, a transport roadway 303 and a track roadway 302 are formed on both sides of the first mining face 301 of the protective layer 300, and the gas in the area of ​​the first mining face 301 is extracted using the roadway of the first mining face 301 of the protective layer 300. The gas extraction intake airway 601 and the gas extraction return airway 602 are connected by a connecting roadway 603. The gas extraction intake airway 601 is connected to the intake airway 100, and the gas extraction return airway 602 is connected to the return airway 200. The track roadway 302 and the transport roadway 303 of the first mining face 301 are both connected to the intake airway 100. During the mining process of the first mining operation 301 of the protective layer 300, the track roadway 302 and the transport roadway 303 are left along the goaf. The two left roadway sections are connected to their corresponding gas extraction airways through connecting roadways to form a complete ventilation system. Specifically, during the mining process of the first mining face of the protective layer 300, the track roadway 302 forms the first retainer roadway 304 through a top-cutting and pressure-relief retainer process, and the transport roadway 303 of the first mining face 301 forms the second retainer roadway 305 through the same process. The track roadway 302 and its first retainer roadway 304 of the first mining face 301 are connected to the gas extraction return airway 602 through the third connecting roadway 703, and the transport roadway 303 and its second retainer roadway 305 of the first mining face 301 are connected to the gas extraction intake airway 601 through the fourth connecting roadway 704. The airflow path in the ventilation system formed is as follows: Figure 6 As shown.

[0077] The above-mentioned layout of the first mining face does not leave coal pillars, thus reducing stress concentration. The first mining face 301 adopts the roof cutting and pressure relief coal pillar-free self-forming roadway process, retaining the two roadways of the first mining face 301, and using the gas drainage intake roadway 601 and the gas drainage return airway 602 to form a complete ventilation system.

[0078] Step 3: As Figure 7-9 As shown, a long borehole 800 is drilled along the roadway of the first mining face 301 using the protective layer 300 to pre-extract gas from the No. 1 long mining face 306 and its roadway area and / or the No. 2 long mining face 308 and its roadway area. Specifically, a long borehole 800 is drilled along the roadway 302 of the first mining face 301 to pre-extract gas from the No. 1 long mining face 306 and the strip gas in the track roadway 307 of the No. 1 long mining face 306; a long borehole 800 is drilled along the roadway 303 of the first mining face 301 to pre-extract gas from the No. 2 long mining face 308 and the strip gas in the transport roadway 309 area of ​​the No. 2 long mining face 308.

[0079] It should be noted that, due to the adoption of the top-cutting and roadway-retention technique, during the mining process, the roof of the goaf collapses along the pre-splitting joints to form roadway walls in the track roadway of the previous mining face. A new roadway is automatically formed using part of the original roadway space and support. The roadway retained from the track roadway of the previous mining face can be used as the transport roadway for the next adjacent mining face. Similarly, due to the adoption of the top-cutting and roadway-retention technique, during the mining process, the roof of the goaf collapses along the pre-splitting joints to form roadway walls in the transport roadway of the previous mining face. A new roadway is automatically formed using part of the original roadway space and support. The roadway retained from the transport roadway of the previous mining face can be used as the track roadway for the next adjacent mining face. Specifically, in this step, the first roadway 304 formed during the mining process of the track roadway 302 of the first mining face 301 of the protective layer 300 can be used as the transport roadway of the mining face 306 of the protective layer 3001; the second roadway 305 formed during the mining process of the transport roadway 303 of the first mining face 301 of the protective layer 300 can be used as the track roadway of the mining face 308 of the protective layer 3002. That is, the two roadways of the first mining face 301 can be used as roadways for adjacent working faces in the protective layer 300 coal seam without leaving coal pillars, eliminating stress concentration around the coal pillars of this coal seam and adjacent coal seams, reducing deformation of the mining roadway to the surrounding rock, and ensuring safe and efficient mine production.

[0080] At the same time, such as Figure 7-10As shown, the gas drainage roadway formed by the roadway of the first mining face 301 of the protective layer 300 can be used to construct the cross-layer drainage borehole 900 to pre-drain the strip gas of No. 1 coal seam 400 and / or No. 2 coal seam 500. In the area where the strip gas treatment meets the standards, the two roadways of No. 1 coal seam 400 and / or the two roadways of No. 2 coal seam 500 can be constructed to form the first mining face 401 of No. 1 coal seam 400 and / or the first mining face 501 of No. 2 coal seam 500. The gas in the area of ​​the first mining face can be extracted by the roadway of the first mining face. During the mining process of the first mining face, the two roadways are left along the goaf. The two roadway sections are connected to the gas drainage roadway or the two roadways of the first mining face 301 of the protective layer 300 through the connecting roadway to form a complete ventilation system. Specifically, utilizing the first roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300, a cross-layer extraction borehole 900 is constructed downwards to pre-extract the strip gas from the No. 2 coal seam 500, which corresponds to the track roadway 502 area of ​​the first mining face 501 of the No. 2 coal seam 500; utilizing the second roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300, a cross-layer extraction borehole 900 is constructed downwards to pre-extract the strip gas from the No. 2 coal seam 500, which corresponds to the area of ​​the track roadway 502 of the first mining face 501 of the No. 2 coal seam 500. The transport roadway 503 area of ​​the first mining face 501 of coal seam 500; a cross-layer drainage borehole 900 is constructed upward from the gas drainage intake airway 601 to pre-drain the strip gas of coal seam 400, which corresponds to the track roadway 402 area of ​​the first mining face 401 of coal seam 400; a cross-layer drainage borehole 900 is constructed upward from the gas drainage return airway 602 to pre-drain the strip gas of coal seam 400, which corresponds to the transport roadway 403 area of ​​the first mining face 401 of coal seam 400.

[0081] In the above implementation method, the gas strip of No. 2 coal seam 500 is pre-extracted by drilling a cross-layer extraction borehole 900 downward through the goaf retention roadway formed by the protective layer 300 first mining face 301. Compared with the method of drilling the cross-layer extraction borehole 900 from the gas extraction roadway to No. 2 coal seam 500, the drilling distance is shortened, the drilling time is reduced, the sealing effect is better, and thus the gas control time of the working face is reduced.

[0082] Furthermore, the gas strips in the No. 2n+1 coal seam can be pre-extracted from the No. 400 coal seam through the cross-layer extraction borehole 900 in the roadway construction of the No. 2n-1 coal seam 400, and / or the gas strips in the No. 2n+2 coal seam 500 can be pre-extracted from the No. 2n+2 coal seam through the cross-layer extraction borehole 900 in the roadway construction of the No. 2n coal seam 400, where n is a positive integer. Specifically, through-seam extraction boreholes 900 can be constructed in the track roadway 402 and transport roadway 403 of the No. 1 coal seam 400 first mining face 401 to pre-extract the strip gas from the No. 3 coal seam. Similarly, through-seam extraction boreholes 900 can be constructed in the track roadway 502 and transport roadway 503 of the No. 2 coal seam 500 first mining face 501 to pre-extract the strip gas from the No. 4 coal seam. In this way, the extraction can be extended upwards and downwards to complete the extraction of strip gas from the roadway areas corresponding to the first mining faces in all coal seams, thus removing obstacles to the excavation of the roadways in the first mining faces of each coal seam.

[0083] Based on the above implementation methods, in some implementation methods, the track roadway and haulage roadway of coal seam 400 (2n+1) are constructed in areas where the strip gas control meets the standards, thereby forming the first mining face of coal seam 400 (2n+1). Gas is extracted from the area of ​​the first mining face of coal seam 400 (2n+1) using the roadway of the first mining face of coal seam 400 (2n+1). During the mining process of the first mining face of coal seam 400 (2n+1), roadways are left along the goaf of the track roadway and haulage roadway. The left-away roadways are connected to the track roadway and haulage roadway of the first mining face of the adjacent coal seam 400 (2n-1) through connecting roadways, forming... A complete ventilation system is implemented. In some embodiments, the track roadway and transport roadway of coal seam 2n+2 500 are constructed in the area where the strip gas control meets the standards, thereby forming the first mining face of coal seam 2n+2 500. The gas in the area of ​​the first mining face of coal seam 2n+2 500 is extracted using the roadway of the first mining face of coal seam 2n+2 500. During the mining process of the first mining face of coal seam 2n+2 500, roadway retention along the goaf is implemented. The roadway retention section is connected to the track roadway and transport roadway of the first mining face of the adjacent coal seam 2n through connecting roadways to form a complete ventilation system.

[0084] Step 4: In each coal seam, use the first mining face roadway of the coal seam to construct a long borehole 800 meters long along the seam to pre-drain the gas from the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area. After the gas control of the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area meets the standards, construct the roadway of the No. 1 mining face and / or the No. 2 mining face to form the No. 1 mining face and / or the No. 2 mining face. Then, the formed No. 1 mining face and / or the No. 2 mining face, which have completed the gas outburst elimination, can be mined, and the roadway along the goaf can be left open.

[0085] Taking protective layer 300 as an example, such as Figure 7 As shown, using the first retaining roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300, a long borehole 800 is constructed along the seam to pre-extract gas from the gas in the long mining face 306 of the protective layer 3001 and the strip gas in the track roadway 307 area of ​​the long mining face 306 of the protective layer 3001. After the gas in the long mining face 306 of the protective layer 3001 and the strip gas in the track roadway 307 area of ​​the long mining face 306 of the protective layer 3001 are treated to meet the standards, the track roadway 307 of the long mining face 306 of the protective layer 3001 is constructed. At this time, the first retaining roadway 304 formed by the track roadway 302 of the first mining face 301 of the protective layer 300 is used as the transport roadway of the long mining face 306 of the protective layer 3001, thus forming the long mining face 306 of the protective layer 3001; on the other hand, as Figure 8 As shown, a long borehole 800 is constructed using the second retaining roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300. This is to pre-extract the gas from the No. 308 long mining face 300 of the protective layer 3002 and the strip gas in the transport roadway 309 area of ​​the No. 308 long mining face 3002. After the gas in the No. 308 long mining face 3002 and the strip gas in the transport roadway 309 area of ​​the No. 308 long mining face 3002 meet the standards, the transport roadway 309 of the No. 308 long mining face 3002 is constructed. At this time, the second retaining roadway 305 formed by the transport roadway 303 of the first mining face 301 of the protective layer 300 is used as the track roadway of the No. 308 long mining face 300, thus forming the No. 308 long mining face 300.

[0086] Taking No. 1 coal seam 400 as an example, the roadway formed by the track roadway 402 of the first mining face 401 of No. 1 coal seam 400 is used for construction of a long borehole 800 along the seam. This is used to pre-extract gas from the No. 1 long mining face 404 and the strip gas in the track roadway area of ​​the No. 1 long mining face 404. After the gas in the No. 1 long mining face 404 and the strip gas in the track roadway area of ​​the No. 1 long mining face 404 are treated to meet standards, the track roadway of the No. 1 long mining face 404 is constructed. At this time, the roadway formed by the track roadway 402 of the first mining face 401 of No. 1 coal seam 400 is used as the transport roadway of the No. 1 long mining face 404, thus forming the No. 1 long mining face 400. On the one hand, using the long borehole 800 formed by the transport roadway 403 of the first mining face 401 of No. 1 coal seam 400, the gas of the No. 1 coal seam 4002 long mining face 405 and the strip gas in the transport roadway area of ​​the No. 1 coal seam 4002 long mining face 405 are pre-extracted. After the gas in the No. 1 coal seam 4002 long mining face 405 and the strip gas in the transport roadway area of ​​the No. 1 coal seam 4002 long mining face 405 are treated to meet the standards, the transport roadway of the No. 1 coal seam 4002 long mining face 405 is constructed. At this time, the roadway formed by the transport roadway 403 of the first mining face 401 of No. 1 coal seam 400 is used as the track roadway of the No. 1 coal seam 4002 long mining face 405, thus forming the No. 1 coal seam 4002 long mining face 405.

[0087] Taking coal seam 500 as an example, a long borehole 800 is drilled along the seam using the roadway 502 formed by the track roadway 502 of the first mining face 501 of coal seam 500. This is used to pre-extract gas from the No. 2 coal seam 5001 longwall face 504 and the strip gas in the track roadway area of ​​the No. 2 coal seam 5001 longwall face 504. After the gas in the No. 2 coal seam 5001 longwall face 504 and the strip gas in the track roadway area of ​​the No. 2 coal seam 5001 longwall face 504 are treated to meet standards, the track roadway of the No. 2 coal seam 5001 longwall face 504 is constructed. At this time, the roadway 502 formed by the track roadway 502 of the first mining face 501 of coal seam 500 is used as the transport roadway of the No. 2 coal seam 5001 longwall face 504, thus forming the No. 2 coal seam 5001 longwall face. 504; On the other hand, using the roadway 503 formed by the transport roadway 503 of the first mining face 501 of No. 2 coal seam, a long borehole 800 is drilled along the seam to pre-extract the gas from the No. 2 coal seam No. 2 long mining face 505 and the strip gas in the transport roadway area of ​​the No. 2 coal seam No. 2 long mining face 505. After the gas in the No. 2 coal seam No. 2 long mining face 505 and the strip gas in the transport roadway area of ​​the No. 2 coal seam No. 2 long mining face 505 are treated to meet the standards, the transport roadway of the No. 2 coal seam No. 2 long mining face 505 is constructed. At this time, the roadway 503 formed by the transport roadway 503 of the first mining face 501 of No. 2 coal seam is used as the track roadway of the No. 2 coal seam No. 2 long mining face 505, thus forming the No. 2 coal seam No. 2 long mining face 505.

[0088] Furthermore, after the formation of either the No. 1 or No. 2 longwall face in any coal seam following the elimination of outbursts, the roadway formed during the mining process can be used to further eliminate outbursts in adjacent unmined faces. Specifically, in any coal seam, an 800mm longwall borehole can be drilled along the seam in the roadway of the No. 2n-1 longwall face to pre-drain the gas from the No. 2n+1 longwall face and its roadway area; alternatively, an 800mm longwall borehole can be drilled along the seam in the roadway of the No. 2n longwall face to pre-drain the gas from the No. 2n+2 longwall face and its roadway area, where n is a positive integer.

[0089] Taking protective layer 300 as an example, during or after the mining of protective layer 3001 mining face 306, the long borehole 800 formed by the roadway 307 of protective layer 3001 mining face 306 can be used to pre-drain the gas from protective layer 3003 mining face and the strip gas in the roadway area of ​​protective layer 3003 mining face 3003; during or after the mining of protective layer 3003 mining face 3003, the long borehole 800 formed by the roadway 3003 mining face 3005 mining face 3005 mining face 3005 mining face 3005 mining face 3005 can be used to pre-drain the gas from protective layer 3005 mining face ... Gas extraction; during or after the mining of the No. 3002 longwall face 308, the long borehole 800 formed by the haulage roadway 309 of the No. 3002 longwall face 308 can be used to pre-extract the gas from the No. 3004 longwall face 304 and the strip gas in the haulage roadway area of ​​the No. 3004 longwall face 3006 longwall face 3006 and the strip gas in the haulage roadway area of ​​the No. 3006 longwall face 3006 longwall face 3006. This process can be repeated to complete the gas extraction of all working faces on one side of the haulage roadway 303 of the first mining face 301 of the No. 300 protective layer.

[0090] Taking coal seam X as an example, during or after the mining of longwall face 1 in coal seam X, an 800mm long borehole formed by the track roadway of longwall face 1 in coal seam X can be used to pre-drain the gas from longwall face 3 in coal seam X and the strip gas in the track roadway area of ​​longwall face 3 in coal seam X; during or after the mining of longwall face 3 in coal seam X, an 800mm long borehole formed by the track roadway of longwall face 3 in coal seam X can be used to pre-drain the gas from longwall face 5 in coal seam X and the strip gas in the track roadway area of ​​longwall face 5 in coal seam X. This process can be repeated to complete the mining of all working faces on one side of the track roadway of coal seam X. Gas drainage: During or after the No. 2 longwall face of coal seam X, the 800mm longwall borehole formed by the haulage roadway of the No. 2 longwall face of coal seam X can be used to pre-drain the gas from the No. 4 longwall face of coal seam X and the strip gas in the haulage roadway area of ​​the No. 4 longwall face of coal seam X; During or after the No. 4 longwall face of coal seam X, the 800mm longwall borehole formed by the haulage roadway of the No. 4 longwall face of coal seam X can be used to pre-drain the gas from the No. 6 longwall face of coal seam X and the strip gas in the haulage roadway area of ​​the No. 6 longwall face of coal seam X. This process can be repeated to complete the gas drainage of all working faces on one side of the haulage roadway of coal seam X. Wherein, X represents a positive integer.

[0091] In this embodiment, a complete ventilation system is required for the construction of the first mining face in each coal seam. For the first mining face 301 of the protective layer 300, a connecting roadway connects the gas drainage roadway to the roadway sections of the two roadways of the first mining face of the protective layer 300. For other coal seams, connecting roadways connect the roadway sections of the two roadways of the first mining face of this coal seam to the roadway sections of the adjacent coal seam working faces. For the complete ventilation of other mining faces in each coal seam besides the first mining face, it can be accomplished by the traditional two-face three-roadway or three-face four-roadway method, or by connecting roadways that cross coal seams and connect to the roadways of adjacent coal seams. Those skilled in the art can choose the appropriate method as needed. In the embodiments of this application, a primary objective of forming a complete ventilation system is to enable ventilation of the roadway sections during mining. This allows for the pre-extraction of gas from adjacent coal seams via cross-seam extraction boreholes (900mm) and the extraction of gas from adjacent working faces within the same coal seam via longitudinal drilling (800mm). This allows for coordinated "mining" and "extraction." The remaining roadways can be used to extract gas from the upper or lower adjacent coal seams, enabling simultaneous gas extraction from the upper or lower adjacent coal seams and mining of the current coal seam's working face. The "mining" and "extraction" between upper and lower coal seams can be systematically coordinated, achieving upper and lower collaborative mining and resolving the issue of tight mining succession. The remaining roadways can also be used to drain gas from adjacent longwall faces in the same coal seam, allowing gas drainage from adjacent longwall faces to be carried out simultaneously with the mining of the current longwall face. The "mining" and "draining" between adjacent longwall faces can be carried out in a coordinated manner, enabling collaborative mining of multiple longwall faces within the coal seam and solving the problem of tight mining succession.

[0092] The above are merely specific embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A three-dimensional gas extraction method for near-field outburst coal seam groups, characterized in that, Includes the following steps: In the outburst coal seam group, a protective layer is identified. The coal seams on one side of the protective layer are named in ascending order of odd numbers, starting from coal seam No. 1, in the direction away from the protective layer. The coal seams on the other side of the protective layer are named in ascending order of even numbers, starting from coal seam No.

2. Each coal seam has a first mining face. The longwall faces on one side of the first mining face are named in ascending order of odd numbers, starting from longwall face No. 1, in the direction away from the first mining face. The longwall faces on the other side of the first mining face are named in ascending order of even numbers, starting from longwall face No.

2. The location of the first mining face and its two roadways is determined in the protective layer. Two gas drainage roadways corresponding to the two roadways of the first mining face are set in the rock strata adjacent to the protective layer. The two gas drainage roadways are used to extract the strip gas in the area of ​​the two roadways of the first mining face of the protective layer. Two roadways are formed on both sides of the first mining face of the protective layer, and the gas in the area of ​​the first mining face is extracted using the roadways of the first mining face. The two gas extraction roadways are connected by a connecting roadway. During the mining process of the first mining face, the two roadways are left along the goaf. The two left roadway sections are connected to their corresponding gas extraction roadways by a connecting roadway to form a complete ventilation system. Using the first mining face of the protective layer, long boreholes are drilled along the layer to pre-drain the gas in the No. 1 mining face and its roadway area and / or the No. 2 mining face and its roadway area. After the gas control of the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area meets the standards, the roadway of the No. 1 longwall face and / or the roadway of the No. 2 longwall face will be constructed to form the No. 1 longwall face and / or the No. 2 longwall face.

2. The three-dimensional gas extraction method for near-field outburst coal seam groups according to claim 1, characterized in that, By constructing cross-layer drainage boreholes in the roadway and gas drainage roadway of the first mining face of the protective layer to pre-drain the strip gas of coal seam No. 1 and / or coal seam No. 2, two roadways of coal seam No. 1 and / or coal seam No. 2 are constructed in the area where the strip gas treatment meets the standards, forming the first mining face of coal seam No. 1 and / or coal seam No.

2. The roadway of the first mining face is used to extract the gas in the area of ​​the first mining face. During the mining process of the first mining face, the two roadways are left along the goaf. The two left roadway sections are connected to the gas drainage roadway or the two roadways of the first mining face of the protective layer through connecting roadways to form a complete ventilation system.

3. The three-dimensional gas extraction method for near-field outburst coal seam groups according to claim 2, characterized in that, Use the cross-layer extraction borehole in the first mining face of coal seam 2n-1 to pre-extract the strip gas of coal seam 2n+1, and / or use the cross-layer extraction borehole in the first mining face of coal seam 2n to pre-extract the strip gas of coal seam 2n+2, where n is a positive integer. In areas where strip gas control meets standards, construct two roadways for coal seam 2n+1 and / or two roadways for coal seam 2n+2 to form the first mining face for coal seam 2n+1 and / or coal seam 2n+2. Utilize the roadways of the first mining face to extract gas from the area within the first mining face. During the retreat mining process of the first mining operation, implement goaf retention roadways for the two roadways. The retained roadway sections are connected to the two roadways of the first mining face of the adjacent coal seam through connecting roadways to form a complete ventilation system.

4. The three-dimensional gas extraction method for near-field outburst coal seam groups according to claim 3, characterized in that, In each coal seam, long boreholes are drilled along the seam using the first mining face roadway of the coal seam to pre-drain the gas from the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area. After the gas control of the No. 1 longwall face and its roadway area and / or the No. 2 longwall face and its roadway area meets the standards, the roadway of the No. 1 longwall face and / or the roadway of the No. 2 longwall face will be constructed to form the No. 1 longwall face and / or the No. 2 longwall face.

5. The three-dimensional gas extraction method for near-field outburst coal seam groups according to claim 4, characterized in that, In any coal seam, gas is pre-extracted from the No. 2n+1 longwall face and its longwall area by using the longwall borehole constructed in the roadway of the No. 2n-1 longwall face, and / or gas is pre-extracted from the No. 2n+2 longwall face and its longwall area by using the longwall borehole constructed in the roadway of the No. 2n longwall face, where n is a positive integer. The same method is used until the gas extraction of the entire coal seam is completed.

6. The three-dimensional gas extraction method for near-field outburst coal seam groups according to claim 1, characterized in that, The gas extraction roadway is either a top extraction roadway located above the protective layer and adjacent to the rock layer, or a bottom extraction roadway located below the protective layer and adjacent to the rock layer.

Images