A method of preventing gas from exceeding the upper corner limit by three-dimensional extraction with source separation and interception

Abstract

The invention belongs to the technical field of mine gas disaster prevention and control, and specifically is a method for preventing upper corner gas from exceeding the limit by three-dimensional extraction through source separation and interception. The method comprises the following steps: S100 - after the mining face and the next adjacent mining face are mined in the coal seam, the air intake tunnel of the next adjacent mining face is arranged on the side of the return tunnel close to the mining face; S200 - in the air intake tunnel of the next adjacent mining face, gas extraction boreholes penetrating the coal pillar are constructed at intervals along the direction of the mining face; S300 - in the air intake tunnel of the next adjacent mining face, a kilometer-long high-position borehole on the roof is constructed to enter the overlying coal seam; S400 - in the air intake tunnel of the next adjacent mining face, a kilometer-long low-position borehole on the floor is constructed to enter the underlying coal seam; S500 - pre-extracting gas from the overlying coal seam and the underlying coal seam through the kilometer-long high-position borehole on the roof and the kilometer-long low-position borehole on the floor; S600 - setting a gas extraction borehole penetrating the coal pillar on the side of the air intake tunnel of the next adjacent mining face close to the mining face.

Description

Technical Field

[0001] The invention belongs to the technical field of mine gas disaster prevention and control, and specifically is a method for preventing upper corner gas from exceeding the limit by three-dimensional extraction through source separation and interception. Background Art

[0002] Gas disasters are the most serious disasters and accidents in my country's coal mine safety production work. Their occurrence will cause great threats to life and safety, property losses and extremely bad social adverse effects. At the same time, as a clean energy, gas extraction and utilization is also the most effective way for coal mining enterprises to control gas. During the mining process of coal seams in high-gas mines, a large amount of gas in the overlying and underlying adjacent coal seams flows into the goaf of the mining face, and flows out to the mining face through the upper corner, causing the gas over-limit phenomenon in the working face, thereby inducing serious gas disasters. At present, the gas extraction of the coal seam, the gas extraction of the adjacent layer and the gas extraction of the goaf are often used to control the gas outburst in the working face. The above-mentioned traditional gas extraction methods have the disadvantages of difficult extraction drilling construction, improper extraction location selection and inaccurate extraction timing in the process of mining coal seams in high-gas mines, which leads to poor gas source control effect, large fluctuations in gas outburst volume in the upper corner of the goaf, and frequent occurrence of gas over-limit phenomenon in the working face. In order to effectively control the gas in the upper corners of the mining face of a close-range coal seam group in a high-gas mine, the present invention proposes a method for three-dimensional extraction of gas from a close-range coal seam group to prevent excessive gas in the upper corners. By arranging ultra-large diameter coal pillar-penetrating gas extraction boreholes in the air intake tunnel of the next adjacent mining face, kilometer-long high-level boreholes along the roof of the overlying coal seam, and kilometer-long low-level boreholes along the floor of the underlying coal seam, the three-dimensional extraction of gas from the upper corners of the mining face of the close-range coal seam group can be achieved, effectively preventing excessive gas in the upper corners. Summary of the invention

[0003] The present invention provides a method for three-dimensional extraction by source separation and interception to prevent gas from exceeding the limit in the upper corner, in order to solve the problems that when mining a group of coal seams in close proximity in a high-gas mine, the goaf of the mining face has multiple gas sources, a large amount of gas outburst, and gas is prone to exceeding the limit in the upper corner.

[0004] The present invention adopts the following technical scheme: a method for three-dimensional extraction with source separation and interception to prevent gas from exceeding the limit in the upper corner, comprising the following steps: S100 - after the mining coal seam is mined, the working face and the next adjacent working face are mined, and the air intake lane of the next adjacent working face is arranged on the side of the return air lane close to the working face; S200 - in the air intake lane of the next adjacent working face, gas extraction drilling holes are constructed at intervals along the direction of the working face; S300 - a kilometer-long drilling hole is constructed at the top of the roof in the air intake lane of the next adjacent working face to enter the overlying coal seam; S400 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S500 - a kilometer-long drilling hole is constructed in the air intake lane of the next adjacent working face to enter the overlying coal seam; S600 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S700 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S800 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S900 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S1000 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S1100 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S1200 - in the air intake lane of the next adjacent working face, a gas extraction drilling hole is constructed at intervals along the direction of the working face; S1300 - in the air intake lane of the next adjacent working face, a gas extraction During the construction of the ventilation tunnel, a kilometer-long hole is drilled into the underlying coal seam at a low position in the bottom plate; S500~Before mining at the mining face, the gas in the overlying coal seam and the underlying coal seam is pre-extracted through a kilometer-long hole in the roof and a kilometer-long hole in the bottom plate to reduce the amount of gas outburst during mining at the mining face; S600~When mining at the mining face begins, a gas extraction borehole that penetrates the coal pillar is set on the side of the ventilation tunnel of the next adjacent mining face, close to the side of the mining face, to extract gas from the goaf of the mining face; at the same time, the depressurized overlying coal seam and the underlying coal seam are continuously extracted through a kilometer-long hole in the roof and a kilometer-long hole in the bottom plate.

[0005] In step S200, a gas extraction borehole through the coal pillar is constructed every 20 to 30 meters along the working face direction in the air intake tunnel of the next adjacent recovery working face, with a diameter of 500 to 1000 mm.

[0006] The specific construction method of step S300 is to determine a point on the roof of the air intake tunnel of the next adjacent mining face, 20 cm away from the side of the mining face, as the position of the first kilometer-long high-position drill hole in the roof. The first section of the drill hole is lifted according to the technical requirements to the unloading boundary line of the overlying coal seam on the mining face. The extension direction of the drill hole is changed here, and the direction is along the inclination direction of the coal seam. The length of the kilometer-long high-position drill hole in the roof in the overlying coal seam is the length of the unloading coal seam. The kilometer-long high-position drill holes in the roof are set in parallel at a distance of 15 m from the previous drilling position.

[0007] The specific construction method of step S400 is to determine a point on the bottom plate of the air intake tunnel of the next adjacent mining face, 20 cm away from the side of the mining face, as the position of the first low-level kilometer-long drill hole in the bottom plate. The first section of the drill hole is lowered at an angle according to technical requirements to the pressure relief boundary line of the underlying coal seam of the mining face. The extension direction of the drill hole is changed here, and the direction is along the inclination direction of the coal seam. The length of the low-level kilometer-long drill hole in the bottom plate in the underlying coal seam is the length of the pressure relief coal seam. The low-level kilometer-long drill holes in the bottom plate are set in parallel at a distance of 15 m from the previous drilling position.

[0008] In step S600, the boreholes for gas extraction through the coal pillar that lag 20 to 30 m behind the mining face are fully opened for extraction, and the remaining boreholes are controlled for extraction or stopped, forming a negative extraction pressure within 20 to 30 m behind the upper corner of the mining face to cut off the outflow of gas from the goaf along the upper corner.

[0009] Compared with the prior art, the present invention adopts a new type of three-dimensional gas extraction method for close-range coal seam groups by combining ultra-large diameter gas extraction boreholes through coal pillars, kilometer-long high-level boreholes along the roof of the overlying coal seam, and kilometer-long low-level boreholes along the floor of the underlying coal seam. The boreholes of this gas extraction method are arranged in the air intake tunnel of the adjacent recovery working face, which is independent of the recovery working face and does not interfere with each other. It is safe and reliable, not only maintaining the normal recovery order, but also greatly improving the extraction cycle; the air intake tunnel of the adjacent preparation working face is in a state of near vacuum because it has not yet been recovered, and the gas extraction efficiency is high; the borehole is a kilometer-long borehole with a large effective extraction range, and is arranged in the pressure relief zone above and below the recovery working face, which greatly increases the extraction range and broadens the gas extraction cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a three-dimensional schematic diagram of source-divided interception and three-dimensional extraction of close-range coal seam groups;

[0011] Figure 2 It is a cross-section diagram of three-dimensional extraction of close-range coal seam groups with source separation and interception;

[0012] Figure 3 This is a schematic diagram of the decompression range of a close-range coal seam group;

[0013] In the figure: 1-mined coal seam, 2-overlying coal seam, 3-underlying coal seam, 4-gas extraction drilling hole through coal pillar, 5-kilometer-long drilling hole at high position in roof; 6-kilometer-long drilling hole at low position in floor, 7-mining working face, 8-next adjacent mining working face, 9-air intake tunnel, 10-return air tunnel, 11-air intake tunnel of mining working face, 12-return air tunnel of mining working face, 13-air intake tunnel, 14-return air tunnel of next adjacent mining working face. DETAILED DESCRIPTION

[0014] The following is a further detailed description of an implementation method of a source-divided interception and three-dimensional extraction method to prevent upper corner gas from exceeding the limit in conjunction with the accompanying drawings.

[0015] A method for three-dimensional extraction by source separation and flow interception to prevent upper corner gas from exceeding the limit includes the following steps.

[0016] S100 - After the coal seam 1 is mined, the working face 7 and the next adjacent working face 8 are mined, and the air intake tunnel 13 of the next adjacent working face 8 is arranged on the side of the return air tunnel 12 close to the working face 7.

[0017] S200~In the air intake tunnel 13 of the next adjacent mining face 8, gas extraction drilling holes 4 are constructed at intervals along the direction of the mining face 7. The gas extraction drilling holes 4 are constructed every 20 to 30 meters along the direction of the working face in the air intake tunnel of the next adjacent mining face, and the diameter is 500 to 1000 mm.

[0018] S300~Construct a kilometer-long drill hole 5 at a high position on the roof in the air intake tunnel 13 of the next adjacent mining working face 8.

[0019] The steps are as follows: a point is determined on the roof of the air intake tunnel 13 of the next adjacent mining face 8, 20 cm away from the side of the mining face 7, as the position of the first kilometer-long high-position drill hole 5 in the roof. The first section of the borehole is lifted according to the technical requirements to the unloading boundary line of the overlying coal seam of the mining face 7. The extension direction of the borehole is changed here, and the direction is along the inclination direction of the coal seam. The length of the kilometer-long high-position drill hole 5 in the roof in the overlying coal seam is the length of the unloading coal seam. The kilometer-long high-position drill hole 5 in the roof is set in parallel at a distance of 15 m from the previous drilling position.

[0020] S400~Construct a kilometer-long borehole 6 at a low position in the bottom plate of the air intake tunnel 13 of the next adjacent mining working face 8.

[0021] The steps are as follows: a point is determined on the bottom plate of the air intake tunnel 13 of the next adjacent mining face 8, 20 cm away from the side of the mining face 7, as the position of the first low-level kilometer-long drill hole 6 in the bottom plate. The first section of the drill hole is lowered at an angle according to technical requirements to the pressure relief boundary line of the underlying coal seam of the mining face 7. The extension direction of the drill hole is changed here, and the direction is along the inclination direction of the coal seam. The length of the low-level kilometer-long drill hole 6 in the bottom plate in the underlying coal seam is the length of the pressure relief coal seam. The low-level kilometer-long drill hole 6 in the bottom plate is set in parallel at a distance of 15 m from the previous drilling position.

[0022] In steps S300 and S400, the pressure relief range of the overlying and underlying coal seams is related to the length of the mining face and the coal seam inclination, and its value is given by Figure 3 and Table 1.

[0023] Table 1 Corresponding relationship between the pressure relief angle δ and the coal seam inclination angle α of close-range coal seams

[0024]

[0025] S500~Before mining at the working face 7, pre-extraction is carried out through the kilometer-long high-position drill hole 5 in the roof and the kilometer-long low-position drill hole 6 in the floor to reduce the amount of gas outburst during mining at the working face.

[0026] S600~When mining starts at the mining face 7, a gas extraction borehole 4 through coal pillar is set on the side of the air intake tunnel 13 of the next adjacent mining face 8 close to the mining face 7 to extract gas from the goaf of the mining face 7; at the same time, the depressurized overlying coal seam and underlying coal seam are continuously extracted through the kilometer-long high-level borehole 5 on the roof and the kilometer-long low-level borehole 6 on the floor.

[0027] The gas extraction borehole 4 that penetrates the coal pillar and lags behind the mining face by 20 to 30 m is fully opened for extraction, while the other boreholes are controlled for extraction or stopped, forming an extraction negative pressure within 20 to 30 m behind the upper corner of the mining face to cut off the outflow of gas from the goaf along the upper corner.

Claims

1. A method for three-dimensional extraction by source separation and flow interception to prevent upper corner gas from exceeding the limit, characterized in that: The following steps are included: S100: after the coal seam (1) is mined, a working face (7) and a next adjacent working face (8) are mined, and an air intake tunnel (13) of the next adjacent working face (8) is arranged on one side of a return air tunnel (12) close to the working face (7); S200: In the air intake tunnel (13) of the next adjacent mining working face (8), drilling holes (4) for gas extraction through the coal pillar are constructed at intervals along the strike of the mining working face (7); S300~constructing a kilometer-long drill hole (5) at a high position on the roof of the air intake tunnel (13) of the next adjacent mining working face (8) to enter the overlying coal seam; The specific construction method of step S300 is to determine a point on the roof of the air intake tunnel (13) of the next adjacent mining face (8) at a distance of 20 cm from the side of the mining face (7) as the position of the first high-position kilometer-long drill hole (5) on the roof, and raise the first section of the drill hole to the pressure relief boundary line of the overlying coal seam of the mining face (7) according to the technical requirements. At this point, the extension direction of the drill hole is changed to the direction along the inclination of the coal seam. The length of the high-position kilometer-long drill hole (5) on the roof in the overlying coal seam is the length of the pressure relief coal seam. The high-position kilometer-long drill hole (5) on the roof is set in parallel at a distance of 15 m from the last drilling position. S400~In the air intake tunnel (13) of the next adjacent mining working face (8), a kilometer-long drilling hole (6) is constructed at the bottom of the construction floor to enter the underlying coal seam; The specific construction method of step S400 is to determine a point on the floor of the air intake tunnel (13) of the next adjacent mining face (8) at a distance of 20 cm from the side of the mining face (7) as the position of the first low-level kilometer-long drill hole (6) in the floor, and the first section of the drill hole is lowered to the pressure relief boundary line of the underlying coal seam of the mining face (7) according to the technical requirements. The extension direction of the drill hole is changed here, and the direction is along the inclination direction of the coal seam. The length of the low-level kilometer-long drill hole (6) in the floor in the underlying coal seam is the length of the pressure relief coal seam. The low-level kilometer-long drill hole (6) in the floor is set in parallel at a distance of 15 m from the last drilling position. S500~Before mining at the mining face (7), pre-extract gas from the overlying coal seam and the underlying coal seam through a kilometer-long drill hole (5) at a high position in the roof and a kilometer-long drill hole (6) at a low position in the floor, so as to reduce the gas outflow during mining at the mining face; S600~When the mining of the mining face (7) begins, a gas extraction borehole (4) through the coal pillar is set on the side of the air intake tunnel (13) of the next adjacent mining face (8) close to the mining face (7) to extract gas from the goaf of the mining face (7); at the same time, the depressurized overlying coal seam and underlying coal seam are continuously extracted through the kilometer-long high-level borehole (5) in the roof and the kilometer-long low-level borehole (6) in the floor.

2. The method for preventing upper corner gas from exceeding the limit by three-dimensional extraction with source separation and flow interception according to claim 1 is characterized in that: In the step S200, a gas extraction drilling hole (4) through the coal pillar is constructed every 20 to 30 meters along the working face direction in the air intake tunnel of the next adjacent recovery working face, and the diameter is 500 to 1000 mm.

3. The method for preventing upper corner gas from exceeding the limit by three-dimensional extraction with source separation and flow interception according to claim 1 is characterized in that: In the step S600, the gas extraction drilling holes (4) through the coal pillar are fully opened for extraction after the drilling holes at 20 to 30 m behind the mining face, while the other drilling holes are controlled for extraction or stopped, so that a negative extraction pressure is formed within a range of 20 to 30 m behind the upper corner of the mining face, thereby cutting off the outflow of gas from the goaf along the upper corner.

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