Goaf gas treatment method suitable for adjacent coal seam of high-gas coal mine

Abstract

The invention belongs to the technical field of coal mine safety, and provides a goaf gas treatment method suitable for adjacent coal seams of a high-gas coal mine. The method comprises the following steps: arranging a basic ventilation loop; arranging a high drainage roadway; an extraction drill site and an extraction drill hole are arranged; arranging an extraction pipeline; before recovery, gas adjacent to a coal seam is pre-extracted through a high negative pressure extraction pipeline; and during recovery, the hole bottom of the extraction drill hole is cut off so as to be communicated with the goaf, and the extraction drill hole extracts gas in the goaf through a low-negative-pressure extraction pipeline. And gradually advancing the stope face, gradually dismantling the closed outer wall of the high drainage roadway, the drainage drill sites, the high negative pressure drainage pipeline and the low negative pressure drainage pipeline in the high drainage roadway, and simultaneously extracting gas in the goaf by the high drainage roadway and the drainage drill holes. The function of the extraction mode is flexibly configured according to the mining mode, and the problem that gas at the upper corner and the air return crossheading exceeds the limit, which cannot be solved by a single high extraction roadway, is solved. The gas extraction efficiency is improved, and the safety production of a stope face is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine safety, and relates to a method for controlling gas in goaf areas adjacent to coal seams in high-gas coal mines. Background Art

[0002] Coal mine gas, as a harmful and potentially dangerous gas in coal mine production, is mainly composed of methane, which is a major threat to coal mine safety production. Methane exists in coal in various forms, mainly including free state and adsorbed state. According to research data, about 90% of methane is deeply hidden in the coal in an adsorbed state, while only about 10% of methane exists in a free state. This special form of existence makes the control of coal mine gas particularly complex and difficult.

[0003] Among the many disasters in coal mine production, gas outburst in goaf is undoubtedly the most serious one. It not only seriously threatens the safe production of coal mines, but also easily leads to excessive gas in the upper corner, which in turn causes the shutdown of working face equipment, causing immeasurable losses to coal mine production. Especially in the deep coal seams of my country's coal mines, due to the particularity of geological conditions, such as high ground stress, high gas pressure and low permeability, the difficulty of gas control is further increased.

[0004] In order to effectively prevent and control gas outburst disasters in coal mine goafs, the industry has explored a variety of methods. Among them, pipe extraction, inclined drilling, roof strike drilling, high-drawn lane, using holes instead of lanes, and large-diameter drilling extraction in adjacent lanes have their own characteristics, but they also have their own limitations.

[0005] Pipeline extraction of gas from goaf is a relatively simple method. A gas extraction pipeline is laid on one side of the return airway of the mining face, one end of the pipeline is connected to the low negative pressure extraction system, and the other end is placed in the goaf for open extraction. This method has simple process and operation management, but the extraction concentration is low, so it is only suitable for situations where the gas outburst in the goaf is not serious.

[0006] The gas extraction from the goaf by inclination drilling is to extract gas by drilling holes at the lower boundary height of the goaf fissure zone in the return air trough of the mining face, close to the mining face. The advantage of this method is that the construction and operation management are simple, and there is no need to dig a drilling site. However, the effective action time and distance of each extraction borehole are short, the extraction effect is generally poor, and the engineering workload is large compared to the top plate strike borehole.

[0007] The roof-oriented drilling method is to dig a drilling site in the return air channel of the mining face, and construct a borehole parallel to the coal seam roof on the side of the drilling site close to the cut eye for extraction. The advantages of this method are higher extraction concentration, smaller drilling volume than the inclined drilling, and continuous extraction. However, the drilling site has a large engineering volume, complex management, and limited extraction volume. When the outflow volume of the goaf of the working face reaches a certain amount, this method cannot solve the problem of exceeding the upper corner limit.

[0008] The high-extraction roadway method is a method similar in principle to the roof-direction drilling method, but using roadways instead of drilling holes can significantly increase the extraction volume. However, this method requires huge investment and is only applicable to situations where gas outflow from the goaf is large and the roof-direction drilling cannot solve the problem.

[0009] The hole-in-place-drift method uses directional drilling with a larger diameter to replace the high-drawing drift. The advantage of this method is that the number of drilling sites is greatly reduced, and the extraction volume is also larger than that of the top plate strike drilling. However, the drilling construction efficiency is lower than that of ordinary drilling, and the investment is between the top plate strike drilling and the high-drawing drift, so the investment is still relatively large.

[0010] The method of extracting gas from the goaf by drilling large diameter holes in the adjacent tunnel is to drill large diameter holes in the adjacent working face directly to the goaf of the working face for extraction. The advantage of this method is that the extraction concentration is higher than the insertion concentration, but the construction process is complicated, the hole is prone to collapse, the casing process is more complicated, the investment is large, and it is not economical.

[0011] In summary, although all the above treatment methods have their own characteristics, they all have shortcomings under certain conditions. Especially when faced with the complex situation that the adjacent coal seam is 9 meters away from the mining layer, the mining layer is 3 meters thick, the adjacent coal seam is 1 meter thick and the gas content is high, even the high-extraction tunnel method, which is considered to be the most effective, cannot completely avoid the phenomenon of excessive gas in the upper corner and return air tunnel. Therefore, a new solution is urgently needed to overcome the defects in the existing technology and ensure the continued safety and stability of coal mine production. Summary of the invention

[0012] In view of this, the purpose of the present invention is to provide a gas control method for goaf areas adjacent to coal seams in high-gas coal mines, so as to significantly improve the pre-extraction rate of adjacent coal seams, ensure that the amount of gas gushing from adjacent coal seams into the goaf areas during the mining of the comprehensive mining working face is controllable, and significantly increase the gas extraction volume in the goaf areas, thereby improving the safety of mine production.

[0013] To achieve the above object, the present invention provides a method for gas control in goaf areas adjacent to coal seams in high-gas coal mines, comprising the following steps:

[0014] Arrangement of basic ventilation circuit: excavation forms a fully mechanized mining face, excavates a centralized return air lane, a centralized main transport lane and a centralized auxiliary transport lane in the rock layer below the coal seam, and further excavates an air intake chute and a return air chute connected to the cut of the fully mechanized mining face;

[0015] Arrangement of high-extraction lane: Arrange high-extraction lane under the floor of the adjacent coal seam in the form of a return air chute parallel to the mining face, and the roof of the high-extraction lane is higher than the roof of the adjacent coal seam;

[0016] Arrangement of extraction drilling sites and extraction boreholes: at least two extraction drilling sites are arranged in the coal wall on the side of the high extraction roadway facing the air inlet chute, and multiple extraction boreholes are opened in the extraction drilling sites towards the cut-off point of the fully mechanized mining face by adopting the directional drilling method of "opening holes in fan shape and ending holes in parallel";

[0017] Arrange the extraction pipeline: Arrange high-negative pressure extraction pipeline and low-negative pressure extraction pipeline in the high extraction lane, and the high-negative pressure extraction pipeline is connected with each extraction borehole;

[0018] Configure the extraction mode: Before mining, each extraction borehole pre-extracts gas from the adjacent coal seam through a high-negative pressure extraction pipeline; during mining, the bottom of the extraction borehole is cut off and connected to the goaf, and the high-negative pressure extraction pipeline and the low-negative pressure extraction pipeline simultaneously extract gas from the goaf.

[0019] Optionally, the configuration of the extraction mode also includes: as the mining face gradually advances, the enclosed outer walls of the high-extraction tunnel and each extraction drilling site are gradually demolished, and the high-negative pressure extraction pipelines and low-negative pressure extraction pipelines in each extraction drilling site are gradually demolished, and the high-extraction tunnel and the extraction boreholes simultaneously extract gas from the goaf.

[0020] Optionally, when arranging the extraction boreholes, the extraction boreholes include a main borehole and sub-boreholes formed by branches of the main borehole, and each main borehole branches to form at most 2 sub-boreholes.

[0021] Optionally, when arranging the extraction boreholes, each extraction drilling site opens a total of 15 extraction boreholes with a hole diameter of 96 mm, and the final hole spacing between two adjacent extraction boreholes is 10 m.

[0022] Optionally, when arranging the extraction boreholes, the horizontal projection of the extraction borehole closest to the high extraction laneway is 10m away from the high extraction laneway.

[0023] Optionally, when arranging the extraction drilling sites, at least two extraction drilling sites are arranged at intervals of 300m in the coal wall on the side of the high extraction tunnel facing the air inlet chute, and the arrangement order of the extraction drilling sites is: arranged in sequence along the direction from the stop mining line to the cutting eye.

[0024] Optionally, when arranging the extraction drilling sites, the first extraction drilling site and the second extraction drilling site are arranged in the coal wall on the side of the high extraction tunnel facing the air inlet chute, and the height of the first extraction drilling site and the second extraction drilling site are 2.6m, the width is 3.5m, and the depth is 5m.

[0025] Optionally, the thickness of the coal seam is 3m, the thickness of the adjacent coal seam is 1m, and the distance between the two is 9m.

[0026] Optionally, when arranging the high-extraction tunnel, the projection of the high-extraction tunnel on the horizontal plane is 35m away from the return air chute, and the height of the high-extraction tunnel is 2.6m and the width is 3m.

[0027] Optionally, when arranging the high-extraction tunnel, the closed position of the high-extraction tunnel is located between the extraction drilling site and the cutting eye, and the distance between the closed outer wall and the extraction drilling site is 10m.

[0028] The beneficial effects of the present invention are:

[0029] The method for controlling gas in goaf disclosed in the present invention provides a new solution for low-permeability coal seams and adjacent coal seams in high-gas coal mines, and has significant beneficial effects, which are specifically reflected in the following aspects:

[0030] First, by arranging the basic ventilation circuit and high-extraction lanes, and making the roof of the high-extraction lanes higher than the roof of the adjacent coal seams, it is ensured that the extraction boreholes can be distributed in the coal seam and the adjacent coal seams, thus physically constructing an effective gas extraction channel for the goaf of the coal seam and the adjacent coal seams. This layout not only facilitates the subsequent gas extraction, but also ensures the efficient extraction process.

[0031] Secondly, the present invention adopts a directional drilling method of "fan-shaped opening holes and parallel end holes", arranges extraction drilling sites at intervals in the coal wall on the side of the high extraction lane facing the air inlet chute, and opens multiple extraction drilling holes. This drilling arrangement can cover the gas accumulation area to the maximum extent and improve the efficiency and accuracy of gas extraction. At the same time, by arranging high-negative pressure extraction pipelines and low-negative pressure extraction pipelines, the present invention realizes the function of flexibly configuring the extraction mode according to the mining mode, further improving the effect of gas control.

[0032] Before mining, each extraction borehole pre-extracts gas from the adjacent layer through a high-negative pressure extraction pipeline, effectively reducing the gas content in the adjacent layer. This step is of great significance for preventing the problem of gas exceeding the limit during mining. During mining, the bottom of the extraction borehole is cut off and connected to the goaf. At this time, the extraction borehole changes from a single pre-extraction function to pre-extraction of gas from the adjacent layer and goaf, solving the problem of gas exceeding the limit in the upper corner and return air chute that cannot be solved by a single high-pressure extraction lane. This transformation not only improves the efficiency of gas extraction, but also ensures the safe production of the mining face.

[0033] In addition, the present invention also achieves fine control of the gas extraction process by optimizing the arrangement of boreholes and the configuration of extraction pipelines. The boreholes include main boreholes and sub-boreholes formed by branches of the main boreholes. Each main borehole branches to form at most two sub-boreholes. This design not only ensures the coverage of extraction, but also avoids the waste of resources. At the same time, the parameters such as the borehole diameter, the terminal hole spacing of adjacent boreholes, and the distance between the high extraction lane and the return air chute have been carefully designed to ensure the best effect of gas extraction.

[0034] In summary, the method for controlling gas in goaf disclosed in the present invention realizes effective control of gas in goafs of adjacent layers of high-gas coal mines by comprehensively using basic ventilation circuits, high-extraction lanes, directional drilling, and flexibly configured extraction modes and other technical means. This method not only improves the efficiency and accuracy of gas extraction, but also ensures the safe production of the mining face, and its indirect economic and social benefits are huge. For those mines with adjacent layers that cannot be mined and have high gas content, the present invention provides a new and effective solution.

[0035] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0037] Figure 1 A top view of the implementation process of the method for gas control in goaf areas adjacent to coal seams in high-gas coal mines provided by the present invention;

[0038] Figure 2 A side view of the implementation process of the method for controlling gas in goaf areas adjacent to coal seams in high-gas coal mines provided by the present invention;

[0039] Figure 3 The present invention provides a flow chart of a method for controlling gas in goaf areas adjacent to coal seams in high-gas coal mines.

[0040] Reference numerals:

[0041] 100-centralized main transport lane; 200-centralized auxiliary transport lane; 300-centralized return air lane; 400-inlet chute; 500-return air chute; 600-high extraction lane; 610-extraction drilling site; 611-first extraction drilling site; 612-second extraction drilling site; 620-extraction borehole; 630-high negative pressure extraction pipeline; 640-low negative pressure extraction pipeline; 700-cutting eye; 800-main coal seam; 900-adjacent coal seam. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0043] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0044] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0045] See also Figure 1 to Figure 3 In order to significantly improve the pre-extraction rate of the adjacent coal seam 900, ensure that the amount of gas gushing from the adjacent coal seam 900 to the goaf during the fully-mechanized mining face is controllable, and significantly increase the gas extraction volume in the goaf, and improve the safety of mine production, the present invention provides a goaf gas control method suitable for the adjacent coal seam 900 of a high-gas coal mine, and the control method includes the following steps:

[0046] Step S100, arranging the basic ventilation circuit: excavating to form a fully mechanized mining face, excavating a centralized return air lane 300, a centralized main transport lane 100 and a centralized auxiliary transport lane 200 in the rock layer below the coal seam 800, and further excavating an air intake chute 400 and a return air chute 500 connected to the cut 700 of the fully mechanized mining face;

[0047] Step S200, arranging a high-extraction tunnel 600: arranging a high-extraction tunnel 600 below the floor of the adjacent coal seam 900 in a manner parallel to the return air chute 500 of the mining face, wherein the roof of the high-extraction tunnel 600 is higher than the roof of the adjacent coal seam 900;

[0048] Step S300, arranging the extraction drilling site 610 and the extraction drilling hole 620;

[0049] Step S400, arranging the extraction pipeline: arranging a high negative pressure extraction pipeline 630 and a low negative pressure extraction pipeline 640 in the high extraction lane 600, and the high negative pressure extraction pipeline 630 is connected to each extraction borehole 620;

[0050] Step S500: configure the extraction mode.

[0051] Step S300 also includes:

[0052] Step S310, at least two extraction drilling sites 610 are arranged in the coal wall of the high extraction tunnel 600 facing the air inlet chute 400;

[0053] Step S320, using the directional drilling method of "opening holes in fan shape and ending holes in parallel" to open a plurality of extraction boreholes 620 in the extraction drilling field 610 toward the cut hole 700 of the fully mechanized mining working face;

[0054] Step S500 also includes:

[0055] Step S510: Before mining, each extraction borehole 620 pre-extracts gas from the adjacent coal seam 900 through the high negative pressure extraction pipeline 630;

[0056] Step S520, during mining, the bottom of the extraction borehole 620 is cut off and connected to the goaf, and the high negative pressure extraction pipeline 630 and the low negative pressure extraction pipeline 640 simultaneously extract gas from the goaf.

[0057] Step S530: As the mining face gradually advances, the enclosed outer walls of the high-extraction tunnel 600 and each extraction drilling site 610 are gradually demolished, and the high-negative pressure extraction pipeline 630 and the low-negative pressure extraction pipeline 640 in each extraction drilling site 610 are gradually demolished. The high-extraction tunnel 600 and the extraction borehole 620 simultaneously extract gas from the goaf through the high-negative pressure extraction pipeline 630 and the low-negative pressure extraction pipeline 640.

[0058] In some optional embodiments, in step S310, at least two extraction drill sites 610 are arranged at intervals of 300 m in the coal wall on the side of the high extraction tunnel 600 facing the air inlet chute 400, and the arrangement order of the extraction drill sites 610 is: arranged in sequence along the direction from the stop mining line to the cutting eye 700.

[0059] In some optional embodiments, in step S310, when arranging the extraction drill site 610, a first extraction drill site 611 and a second extraction drill site 612 are arranged in the coal wall on the side of the high extraction tunnel 600 facing the air inlet chute 400, and the height, width and depth of the first extraction drill site 611 and the second extraction drill site 612 are 2.6 m, 3.5 m and 5 m respectively.

[0060] In some optional embodiments, in step S320, the extraction borehole 620 includes a main borehole and sub-bores formed by branches of the main borehole, and each main borehole branches to form at most two sub-bores. Each extraction drilling site 610 has a total of 15 extraction boreholes 620 with a hole diameter of 96 mm, and the horizontal projection of the borehole closest to the high-extraction lane 600 is 10 meters away from the high-extraction lane 600, and the terminal hole spacing between two adjacent extraction boreholes 620 is 10 meters.

[0061] In some optional embodiments, the thickness of the coal seam 800 is 3m, the thickness of the adjacent coal seam 900 is 1m, and the distance between the two is 9m. In step S200, when the high-extraction tunnel 600 is arranged, the projection of the high-extraction tunnel 600 on the horizontal plane is 35m away from the return air chute 500, and the height of the high-extraction tunnel 600 is 2.6m and the width is 3m. When the high-extraction tunnel 600 is arranged, the closed position of the high-extraction tunnel 600 is located between the extraction drilling site 610 and the cut eye 700, and the closed outer wall is 10m away from the extraction drilling site 610.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling gas in goaf areas adjacent to coal seams in high-gas coal mines, characterized by: The following steps are involved: Arrangement of basic ventilation circuit: excavation to form a fully mechanized mining face, excavation of a centralized return air lane (300), a centralized main transport lane (100) and a centralized auxiliary transport lane (200) in the rock layer below the coal seam (800), and further excavation of an air intake chute (400) and a return air chute (500) connected to the cut-off (700) of the fully mechanized mining face; Arrangement of high extraction roadway: Arrangement of high extraction roadway (600) along the bottom plate of the adjacent coal seam (900), the top plate of the high extraction roadway (600) being higher than the top plate of the adjacent coal seam (900); Arrange the extraction drilling site and extraction drilling holes: arrange at least two extraction drilling sites (610) in the coal wall on the side of the high extraction roadway (600) facing the air inlet chute (400), and use the directional drilling method of "opening holes in fan shape and end holes in parallel" to open multiple extraction drilling holes (620) in the extraction drilling site (610) towards the cut hole (700) of the fully mechanized mining working face; Arranging extraction pipelines: arranging a high negative pressure extraction pipeline (630) and a low negative pressure extraction pipeline (640) in the high extraction lane (600), wherein the high negative pressure extraction pipeline (630) is connected to each extraction borehole (620); Configuration extraction mode: before mining, each extraction borehole (620) pre-extracts gas from the adjacent coal seam (900) through a high-negative pressure extraction pipeline (630); during mining, the bottom of the extraction borehole (620) is cut off and connected to the goaf, and the high-negative pressure extraction pipeline (630) and the low-negative pressure extraction pipeline (640) simultaneously extract gas from the goaf.

2. The method for controlling gas in goaf according to claim 1, characterized in that: The configuration of the extraction mode also includes: as the mining face gradually advances, the enclosed outer wall of the high extraction lane (600) and each extraction drilling site (610) are gradually dismantled, and the high negative pressure extraction pipeline (630) and the low negative pressure extraction pipeline (640) in each extraction drilling site (610) are gradually dismantled, and the high extraction lane (600) and the extraction borehole (620) simultaneously extract gas from the goaf.

3. The method for controlling gas in goaf according to claim 1, characterized in that: When arranging the extraction borehole (620), the extraction borehole (620) includes a main borehole and sub-boreholes formed by branches of the main borehole, and each main borehole branches to form at most two sub-boreholes.

4. The method for controlling gas in goaf according to claim 1 or 3, characterized in that: When arranging the extraction boreholes (620), each extraction drilling site (610) has 15 extraction boreholes (620) with a hole diameter of 96 mm, and the final hole spacing between two adjacent extraction boreholes (620) is 10 m.

5. The method for controlling gas in goaf according to claim 1 or 3, characterized in that: When arranging the extraction boreholes (620), the horizontal projection of the extraction borehole (620) closest to the high extraction lane (600) is 10 m away from the high extraction lane (600).

6. The method for controlling gas in goaf according to claim 1, characterized in that: When arranging the extraction drill sites (610), at least two extraction drill sites (610) are arranged at intervals of 300 m in the coal wall on the side of the high extraction tunnel (600) facing the air inlet chute (400). The arrangement order of the extraction drill sites (610) is: arranged in sequence along the direction from the stop mining line to the cutting eye (700).

7. The method for controlling gas in goaf according to claim 1 or 6, characterized in that: When arranging the extraction drill site (610), a first extraction drill site (611) and a second extraction drill site (612) are arranged in the coal wall on the side of the high extraction tunnel (600) facing the air inlet chute (400), and the height of the first extraction drill site (611) and the second extraction drill site (612) are 2.6 m, the width is 3.5 m, and the depth is 5 m.

8. The method for controlling gas in goaf according to claim 1, characterized in that: The thickness of the present coal seam (800) is 3 m, the thickness of the adjacent coal seam (900) is 1 m, and the distance between the two is 9 m.

9. The method for controlling gas in goaf according to claim 8, characterized in that: When the high-extraction tunnel (600) is arranged, the projection of the high-extraction tunnel (600) on the horizontal plane is 35m away from the return air chute (500), and the height of the high-extraction tunnel (600) is 2.6m and the width is 3m.

10. The method for controlling gas in goaf according to claim 1, characterized in that: When arranging the high-extraction tunnel (600), the closed position of the high-extraction tunnel (600) is located between the extraction drilling site (610) and the cutting eye (700), and the closed outer wall is 10m away from the extraction drilling site (610).

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