Detection method for coal spontaneous combustion three zones in goaf of fully mechanized coal mining face

Abstract

The invention discloses a fully mechanized coal mining face goaf coal spontaneous combustion three-zone detection method, a fully mechanized coal mining face comprises a goaf, a working face, an open-off cut, an air inlet way and an air return way, and the detection method comprises the steps that S1, a plurality of drilling channels are drilled from the ground to the goaf, and a plurality of drilling terminals are mutually spaced in the inclined length direction of the fully mechanized coal mining face; s2, a plugging assembly and an exhaust pipe are arranged in the drilling channel, the plugging assembly plugs the opening of the starting end of the drilling hole to form a detection cavity, one end of the exhaust pipe penetrates through the plugging assembly and extends into the detection cavity, and the other end of the exhaust pipe is connected with a gas sampling device; s3, regularly sampling the gas in each detection cavity by using the sampling device to obtain an oxygen concentration value in the detection cavity, and stopping sampling until the detected oxygen concentration value is lower than a preset oxygen concentration threshold value; and S4, determining the distribution range of the spontaneous combustion three zones of the goaf according to a corresponding change rule between the detected oxygen concentration value in the detection cavity and the distance of the working face.

Description

Technical Field

[0001] The invention relates to the technical field of disaster prevention and control of goaf areas in coal mines, and in particular to a method for detecting three spontaneous combustion zones of coal in goaf areas of fully mechanized mining working faces. Background Art

[0002] With the popularization of high-yield and efficient comprehensive mechanized top coal caving technology, the efficiency of coal mining has been greatly improved. Limited by the mining process, a large amount of floating coal will inevitably be left in the goaf during the mining process, and the distribution is uneven. Under the condition of long-term air leakage and oxygen supply, oxidation and spontaneous combustion are very likely to occur, which brings huge fire safety hazards to the goaf of the coal mining working face and seriously threatens the health and safety of mine workers. Therefore, it is very important to master the distribution of the "three zones" of spontaneous combustion in the goaf of the coal mining working face to guide the safe advancement speed of the working face and select reasonable goaf nitrogen injection and grouting parameters, as well as to take other timely and effective fire prevention and extinguishing measures.

[0003] There is no unified standard and basis for the division of the "three zones" in goaf areas. There are three main division methods, namely the critical oxygen concentration method, the goaf air leakage velocity method, and the goaf temperature rise rate method. The above methods all have their own advantages and disadvantages. In combination with the actual application of most mines, the critical oxygen concentration method is mostly used. This method is the most widely used division method with good effect and on-site consistency.

[0004] In the related technologies, the "three zones" measurement scheme of the goaf is carried out in the mining face, which can be mainly divided into two measurement methods: Method 1: Setting measurement points in the air inlet and return chute of the coal mining face, and taking gas samples for detection after the measurement points enter the goaf; Method 2: Setting measurement points along the conveyor at the rear of the working face, and taking gas samples for detection after the measurement points enter the goaf. After the measurement points are arranged in the above two methods, a protective casing is laid, and a bundle pipe for connecting the measurement points and the gas sampling device is set in the casing. As the working face is mined, gas samples are drawn from each measurement point at regular intervals every day for analysis, and finally the distribution of the "three zones" of spontaneous combustion in the goaf of the coal mining face is obtained according to the change range of oxygen concentration.

[0005] However, it was discovered on site that as the working face continued to move forward, the protective casing was easily damaged and compacted by the coal gangue that collapsed from the roof of the goaf, causing the bundle tube to break. As a result, the collected sampling gas was unable to truly reflect the gas composition at the measuring point, resulting in inaccurate division of the "three zones" of spontaneous combustion in the goaf of the coal mining working face. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a method for detecting the three zones of spontaneous combustion of coal in the goaf of a fully-mechanized mining face, in which a borehole channel for gas sampling is directly drilled from the ground toward the goaf without pre-buried bundle pipes, so there is no risk of the exhaust pipeline being damaged during the mining process of the working face, thereby improving the authenticity of the sampled gas, thereby improving the accuracy of the division of the "three zones" of spontaneous combustion.

[0007] According to the detection method of three zones of coal spontaneous combustion in the goaf of a fully mechanized mining face according to an embodiment of the present invention, the fully mechanized mining face comprises a goaf, a working face, a cut-eye, an air inlet lane and a return air lane, the cut-eye is located between the goaf and the working face, the cut-eye is suitable for arranging a working face support, the air inlet lane and the return air lane are respectively arranged at both ends of the cut-eye in the length direction and are connected to each other through the cut-eye, and the detection method comprises:

[0008] S1: Drilling a plurality of drilling channels from the ground toward the goaf, the two ends of each drilling channel in the length direction are respectively a drilling start end and a drilling end end, each drilling end end is located in the goaf, each drilling start end is located on the ground, and the plurality of drilling ends are spaced apart from each other in the inclined length direction of the fully mechanized mining working face;

[0009] S2: a plugging assembly and an air extraction pipe are arranged in the drilling channel, the plugging assembly is used to plug the open opening at the starting end of the drilling hole so as to form a sealed detection cavity in the drilling channel, one end of the air extraction pipe passes through the plugging assembly to extend into the detection cavity, and the other end of the air extraction pipe is exposed above the ground and connected to a gas sampling device;

[0010] S3: During the mining process of the working face, the gas in each detection cavity is sampled periodically by using the gas sampling device, and the components of the sampled gas in each detection cavity are detected to obtain the oxygen concentration value in each detection cavity, and the oxygen concentration value of each detection cavity and the distance of the corresponding drilling terminal from the working face are recorded. As the working face is continuously mined, the oxygen concentration value of the sampled gas will decrease until the sampling is stopped when it is detected that the oxygen concentration value in the sampled gas is lower than the preset oxygen concentration threshold value;

[0011] S4: Determine the distribution range of the three spontaneous combustion zones in the goaf of the coal mining working face based on the corresponding change pattern between the oxygen concentration value in each detection chamber and the corresponding distance between the drilling terminal and the working face.

[0012] In addition, the method for detecting the three spontaneous combustion zones of coal in the goaf of a fully-mechanized mining face according to the embodiment of the present invention may also have the following additional technical features:

[0013] According to one embodiment of the present invention, the distance between the centers of two adjacent drilling terminals in the inclined length direction of the fully mechanized mining working face is equal.

[0014] According to one embodiment of the present invention, the centers of the plurality of drilling terminals are located on the same straight line, and the straight line is parallel to the inclined length direction of the comprehensive mining working face.

[0015] According to one embodiment of the present invention, the drilling channel includes a first drilling channel section and a second drilling channel section connected to each other, the drilling starting end is formed at one end of the first drilling channel section, the drilling terminal is formed at one end of the second drilling channel section, the inner diameter of the first drilling channel section is larger than the inner diameter of the second drilling channel section, a step surface is formed between the other end of the first drilling channel section and the other end of the second drilling channel section, and the plugging assembly includes: a sealing plate, the sealing plate is arranged in the first drilling channel section and supported on the step surface, the sealing plate is used to seal the second drilling channel section, and the detection cavity is defined between the second drilling channel section and the sealing plate; a grouting layer, the grouting layer is arranged in the first drilling channel section and is located on the side of the sealing plate away from the second drilling channel section, and the surface of the grouting layer on the side away from the sealing plate is flush with the ground.

[0016] According to an embodiment of the present invention, the blocking plate is a steel plate.

[0017] According to one embodiment of the present invention, the grouting material of the grouting layer is expansive cement slurry.

[0018] According to an embodiment of the present invention, the preset oxygen concentration threshold is 8%.

[0019] According to one embodiment of the present invention, the oxygen concentration value greater than 18% is a heat dissipation zone, the oxygen concentration value less than 8% is a suffocation zone, and the oxygen concentration value between 8% and 18% is an oxidation zone.

[0020] According to the method for detecting the three zones of spontaneous combustion of coal in the goaf of a comprehensive mining working face in an embodiment of the present invention, a drilling channel for gas sampling is drilled directly from the ground toward the goaf without the need for pre-buried bundle pipes. Therefore, during the mining process of the working face, there is no risk of the exhaust pipeline being damaged, thereby improving the authenticity of the sampled gas and thereby improving the accuracy of the division of the "three zones" of spontaneous combustion.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of drilling a drilling channel from the ground toward the goaf in a method for detecting three spontaneous combustion zones of coal in a goaf of a fully mechanized mining face according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 A top view of the distribution of the drilling terminals of the drilling channels shown in FIG. 1 within the goaf;

[0025] Figure 3 This is a schematic diagram of the "three zones" division of the goaf area of ​​the comprehensive mining working face.

[0026] Reference numerals:

[0027] Comprehensive mining working face 100; goaf 101; heat dissipation zone 1011; oxidation zone 1012; asphyxiation zone 1013; working face 102; cut eye 103; air inlet lane 104; return air lane 105; drilling channel 200; drilling starting end 200a; drilling terminal 200b; detection chamber 200c; first drilling channel section 201; second drilling channel section 202; step surface 203; plugging assembly 300; plugging plate 301; grouting layer 302; exhaust pipe 400; gas sampling device 500. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] Reference below Figure 1-Figure 3 A method for detecting three spontaneous combustion zones of coal in the goaf 101 of a fully mechanized mining face 100 according to an embodiment of the present invention is described.

[0030] refer to Figure 1-Figure 3 As shown, the comprehensive mining working face 100 includes a goaf 101, a working face 102, a cutting eye 103, an air inlet lane 104 and a return air lane 105. The cutting eye 103 is located between the goaf 101 and the working face 102. The cutting eye 103 is suitable for arranging a working face support and coal mining equipment. The air inlet lane 104 and the return air lane 105 are respectively arranged at both ends of the length direction of the cutting eye 103 and are connected to each other through the cutting eye 103, thereby forming an air inlet and return system.

[0031] It is understandable that during coal mining, the method of mining is generally adopted, that is, before coal mining, the air inlet tunnel 104 and the return air tunnel 105 are first opened to penetrate into the coal seam, and then the air inlet tunnel 104 and the return air tunnel 105 are opened through the cut hole to form an air inlet and return air system. The coal body surrounded by the air inlet tunnel 104, the return air tunnel 105 and the cut hole forms the initial working face 102, and the working face support and coal mining equipment are set at the cut hole position, and the working face 102 can be continuously pushed forward from the cut hole position along the length extension direction of the air inlet tunnel 104 and the return air tunnel 105.

[0032] During the mining process of the working face 102, the area where the coal body is located after mining will be covered by the coal gangue from the roof collapse to form the goaf 101. As the working face 102 is continuously mined, the area of ​​the goaf 101 becomes larger and larger, and the area of ​​the working face 102 becomes smaller and smaller. The area between the goaf 101 and the working face 102 constitutes the cut-eye 103. As the working face 102 is continuously mined, the position of the cut-eye 103 is also constantly changing. The position of the cut-eye 103 is constantly moving forward along the length extension direction of the air inlet lane 104 and the return air lane 105. The working face support and coal mining equipment are located in the cut-eye 103, and the working face support and coal mining equipment will also change with the change of the position of the cut-eye 103.

[0033] It is understandable that in the actual mining process of the working face 102, not only the area where the coal body where the mining is completed is located will be covered by the coal gangue of the collapsed roof, but also the area of ​​the air inlet lane 104 and the return air lane 105 corresponding to the part of the coal body and the position of the opening of the cutting eye will be covered by the collapsed coal gangue. Therefore, the "mined-out area 101" described in the embodiment of the present application includes not only the area where the coal body where the mining is completed is located, but also the area of ​​the air inlet lane 104 and the return air lane 105 corresponding to the area where the part of the coal body is located, and the area where the opening of the cutting eye is located.

[0034] The method for detecting three spontaneous combustion zones of coal in the goaf 101 of the fully-mechanized mining face 100 according to the embodiment of the present invention comprises the following steps:

[0035] S1: Drill multiple drilling channels 200 from the ground toward the goaf 101, the two ends of each drilling channel 200 in the length direction are respectively a drilling start end 200a and a drilling terminal 200b, each drilling terminal 200b is located in the goaf 101, each drilling start end 20a is located on the ground, and multiple drilling terminals 200b are spaced apart from each other in the inclined length direction of the fully mechanized mining face 100. In the embodiment of the application, the inclined length direction of the fully mechanized mining face 100 is parallel to the length extension direction of the cut eye 103.

[0036] The location of the center of the "drilling terminal 200b" of each drilling channel 200 is the location of the gas sampling point of the goaf 101.

[0037] It should be noted that in the present application, the drilling of the "drilling channel 20070" is performed after a certain range of the goaf 101 is formed, and the specific range of the goaf 101 after the drilling needs to be selected according to the actual situation. For example, the drilling of the drilling channel 200 can be performed when the length of the goaf 101 along the length extension direction of the air inlet tunnel 104 and the return air tunnel 105 reaches 20m, 30m or 50m.

[0038] S2: A plugging assembly 300 and an air extraction pipe 400 are arranged in the drilling channel 200. The plugging assembly 300 is used to plug the open opening of the drilling start end 200a so as to form a sealed detection cavity 200c in the drilling channel 200. One end of the air extraction pipe 400 passes through the plugging assembly 300 to extend into the detection cavity 200c, and the other end of the air extraction pipe 400 is exposed above the ground and connected to the gas sampling device 500. The gas sampling device 500 is arranged on the ground. Optionally, the gas sampling device 500 can be a gas sampling pump.

[0039] S3: During the mining process of the working face 102, the gas sampling device 500 is used to regularly sample the gas in each detection cavity 200c, and the components of the sampled gas in each detection cavity 200c are detected to obtain the oxygen concentration value in each detection cavity 200c, and the oxygen concentration value of each detection cavity 200c and the distance of the corresponding drilling terminal 200b from the working face 102 are recorded. As the working face 102 is continuously mined, the area of ​​the goaf 101 will gradually increase, and the area of ​​the working face 102 will gradually decrease. Therefore, the distance between the drilling terminal 200b and the working face 102 will continue to increase, and the drilling terminal 200b gradually enters the depth of the goaf 101. The oxygen concentration value of the sampled gas will decrease until the sampling is stopped when the oxygen concentration value in the sampled gas is detected to be lower than the preset oxygen concentration threshold. Optionally, the oxygen concentration threshold can be 8%.

[0040] S4: According to the corresponding variation law between the oxygen concentration value in each detection cavity 200c and the distance between the corresponding drilling terminal 200b and the working face 102, the distribution range of the three spontaneous combustion zones in the goaf 101 of the coal mining working face 102 is determined. How to determine the division of the three zones by the corresponding variation law between the oxygen concentration value and the distance between the corresponding drilling terminal 200b and the working face 102 is common knowledge to those skilled in the art and will not be described here.

[0041] See also Figure 3The "three zones" of the goaf 101 include the heat dissipation zone 1011, the oxidation zone 1012 and the asphyxiation zone 1013. The heat dissipation zone 1011 has sufficient oxygen supply conditions, but due to the large air leakage, the small heat generated in the early stage of coal oxidation and spontaneous combustion is lost with the wind. The coal oxidation process always stays in the slow development stage, and it is not easy for coal spontaneous combustion to occur. It should be pointed out that the oxygen concentration is used as an indicator to define the heat dissipation zone 1011 and the oxidation zone 1012. It is not because the oxygen concentration is greater than a certain value and cannot spontaneously ignite, but because the air leakage wind speed in this area is too high to take away the heat generated by oxidation. Therefore, the heat dissipation zone 1011 is often called the "cooling zone"; the oxidation zone 1012 has sufficient oxygen supply conditions, and because of the small air leakage, the oxidation heat storage environment is better, the coal oxidation self-heating process can continue, and finally lead to the occurrence of coal spontaneous combustion. Due to the lack of oxygen in the asphyxiation zone 1013, the coal oxidation and spontaneous combustion process will not be able to proceed.

[0042] The "three zones" of the goaf 101 are divided by the oxygen concentration critical value index parameter, and the oxygen concentration critical value can be selected as needed. Optionally, the oxygen concentration critical value can be 8% and 18%. Specifically, the oxygen concentration value greater than 18% is the heat dissipation zone 1011; the oxygen concentration value greater than or equal to 8% and less than or equal to 18% is the oxidation zone 1012; the oxygen concentration value less than 8% is the asphyxiation zone 1013.

[0043] According to the method for detecting the three zones of spontaneous combustion of coal in the goaf 101 of the comprehensive mining face 100 according to the embodiment of the present invention, a drilling channel 200 for gas sampling is drilled directly from the ground toward the goaf 101 without pre-buried bundle pipes. Therefore, during the mining process of the working face 102, there is no risk of the exhaust pipeline being damaged, thereby improving the authenticity of the sampled gas and thereby improving the accuracy of the division of the "three zones" of spontaneous combustion.

[0044] In one embodiment of the present invention, see Figure 2 , the centers of two adjacent drilling terminals 200b are equidistant in the inclination length direction of the fully mechanized mining face 100. In other words, the multiple drilling terminals 200b are evenly distributed along the inclination length direction of the fully mechanized mining face 100, so that the division accuracy of the spontaneous combustion "three zones" of the goaf 101 can be improved.

[0045] In one embodiment of the present invention, please continue to refer to Figure 2 The centers of multiple drilling terminals 200b are located on the same straight line, and the straight line is parallel to the inclined length direction of the comprehensive mining working face 100.

[0046] In one embodiment of the present invention, see Figure 1The drilling channel 200 includes a first drilling channel section 201 and a second drilling channel section 202 connected to each other, a drilling start end 200a is formed at one end of the first drilling channel section 201, a drilling terminal 200b is formed at one end of the second drilling channel section 202, an inner diameter of the first drilling channel section 201 is greater than an inner diameter of the second drilling channel section 202, a step surface 203 is formed between the other end of the first drilling channel section 201 and the other end of the second drilling channel section 202, and a plugging assembly 300 includes The plugging plate 301 and the grouting layer 302, the plugging plate 301 is arranged in the first drilling channel section 201 and supported on the step surface 203, the plugging plate 301 is used to plug the second drilling channel section 202, and the detection cavity 200c is defined between the second drilling channel section 202 and the plugging plate 301, the grouting layer 302 is arranged in the first drilling channel section 201 and is located on the side of the plugging plate 301 away from the second drilling channel section 202, and the surface of the side of the grouting layer 302 away from the plugging plate 301 is flush with the ground. It should be noted that the grouting layer 302 is formed by grouting. The plugging assembly 300 of the embodiment of the present invention has a simple structure and a good plugging effect.

[0047] Optionally, the blocking plate 301 is a steel plate, so that the blocking plate 301 has high structural strength and is not easily corroded.

[0048] Optionally, the grouting material of the grouting layer 302 is expansive cement slurry.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0050] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining working face, characterized in that: The fully mechanized mining working face comprises a goaf, a working face, a cut-out, an air inlet lane and a return air lane, wherein the cut-out is located between the goaf and the working face, and a working face support is suitable for being arranged in the cut-out, and the air inlet lane and the return air lane are respectively arranged at two ends of the cut-out in the length direction and are connected to each other through the cut-out, and the detection method comprises: S1: Drilling a plurality of drilling channels from the ground toward the goaf, the two ends of each drilling channel in the length direction are respectively a drilling start end and a drilling end end, each drilling end end is located in the goaf, each drilling start end is located on the ground, and the plurality of drilling ends are spaced apart from each other in the inclined length direction of the fully mechanized mining working face; S2: a plugging assembly and an air extraction pipe are arranged in the drilling channel, the plugging assembly is used to plug the open opening at the starting end of the drilling hole so as to form a sealed detection cavity in the drilling channel, one end of the air extraction pipe passes through the plugging assembly to extend into the detection cavity, and the other end of the air extraction pipe is exposed above the ground and connected to a gas sampling device; S3: During the mining process of the working face, the gas in each detection cavity is sampled periodically by using the gas sampling device, and the components of the sampled gas in each detection cavity are detected to obtain the oxygen concentration value in each detection cavity, and the oxygen concentration value of each detection cavity and the distance of the corresponding drilling terminal from the working face are recorded. As the working face is continuously mined, the oxygen concentration value of the sampled gas will decrease until the sampling is stopped when it is detected that the oxygen concentration value in the sampled gas is lower than the preset oxygen concentration threshold value; S4: Determine the distribution range of the three spontaneous combustion zones in the goaf of the coal mining working face based on the corresponding change pattern between the oxygen concentration value in each detection chamber and the corresponding distance between the drilling terminal and the working face.

2. The method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining face according to claim 1 is characterized in that: The distance between the centers of two adjacent drilling terminals in the inclination length direction of the comprehensive mining working face is equal.

3. The method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining face according to claim 1 is characterized in that: The centers of the multiple drilling terminals are located on the same straight line, and the straight line is parallel to the inclined length direction of the comprehensive mining working face.

4. The method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining face according to claim 1 is characterized in that: The drilling channel comprises a first drilling channel section and a second drilling channel section connected to each other, the drilling start end is formed at one end of the first drilling channel section, the drilling end end is formed at one end of the second drilling channel section, the inner diameter of the first drilling channel section is greater than the inner diameter of the second drilling channel section, a step surface is formed between the other end of the first drilling channel section and the other end of the second drilling channel section, and the plugging assembly comprises: a blocking plate, the blocking plate being arranged in the first drilling channel section and supported on the step surface, the blocking plate being used to block the second drilling channel section, and the detection cavity being defined between the second drilling channel section and the blocking plate; The grouting layer is arranged in the first drilling channel section and is located on the side of the sealing plate away from the second drilling channel section, and the surface of the grouting layer on the side away from the sealing plate is flush with the ground.

5. The method for detecting three zones of spontaneous combustion of coal in goaf of fully mechanized mining face according to claim 4 is characterized in that: The blocking plate is a steel plate.

6. The method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining face according to claim 4 is characterized in that: The grouting material of the grouting layer is expansion cement slurry.

7. The method for detecting three spontaneous combustion zones of coal in the goaf of a fully mechanized mining face according to any one of claims 1 to 6, characterized in that: The preset oxygen concentration threshold is 8%.

8. The method for detecting three spontaneous combustion zones of coal in goaf of fully mechanized mining face according to claim 7 is characterized in that: The oxygen concentration value greater than 18% is a heat dissipation zone, the oxygen concentration value less than 8% is a suffocation zone, and the oxygen concentration value between 8% and 18% is an oxidation zone.

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