Multi-complex medium water control method for shallow coal seam

Abstract

The invention belongs to the field of coal mine water prevention and control, and particularly relates to a shallow coal seam multiple complex medium water prevention and control method. The main roadway is arranged in a shallow floor rock stratum and is connected with a section roadway through a cross-cut, so that the stability of the main roadway can be ensured; the concept of water guide critical elevation is provided, an L-shaped coal face is arranged below the water guide critical elevation to form a goaf for water storage, and the goaf is not affected by multiple complex medium water during stoping; and then multiple complex medium water is discharged into the water storage goaf, and the safe stoping problem of other coal seams in the mining area, especially the coal seams above the critical water diversion elevation is solved. Stopping other coal seams of the mining area by adopting a rectangular coal face; the waterproof coal pillars are arranged between the L-shaped coal face and the rectangular coal face, so that the influence of water discharged into the goaf on the recovery of the rectangular coal face can be avoided. The method can solve the problem of safe recovery of multiple complex medium water of the shallow coal seam to the coal seam, and can improve the coal recovery rate to the maximum extent.

Description

Technical Field

[0001] The invention belongs to the field of coal mine water prevention and control, and specifically relates to a method for preventing and controlling water in multiple complex media in shallow coal seams. Background Art

[0002] Surface water, loose layer water, bedrock water (including bedrock weathering layer, which is often found in the outcrops of rock formations immediately below the loose layer; and rock formations with high porosity that can store water, such as sandstone) are common multiple complex media water that affect coal mining. There are a large number of shallow coal seams in Xinjiang, and coal seam mining is often affected by surface water, loose layer water, and weathered bedrock water; in addition, burnt areas are common in coal seam outcrops. The coal rock mass in the burnt area is mainly caused by spontaneous combustion of coal seams, and has structures and structures such as vitrification, whitening, melting, residue, pores, micro-columnar joints, brecciated, collapse, and crack filling; the cracks and pores of the coal rock mass in the burnt area are developed, providing a good space for groundwater runoff and storage, and often become the main aquifer in the mining area together with the loose layer and weathered bedrock aquifer.

[0003] Since coal seams are relatively shallow, the rock layers above them collapse after coal seam mining, and the water-conducting fracture zones in some areas will directly reach the loose layer and then the surface. At this time, the water in the loose layer and the weathered bedrock water will flow into the lower part of the mine along the water-conducting fracture zones. If there is a surface water system, the surface water will also flow into the mine, causing floods and endangering life and property safety; and rainwater in the rainy season will also enter the mine from the water-conducting fractures. If only the deeper coal seams are mined, the development of water-conducting fractures will not penetrate the entire rock layer, which will cause a huge waste of coal resources, especially in Xinjiang, an area dominated by shallow coal seams. Therefore, how to safely recover shallow coal seams and prevent and control multiple complex medium water has become a difficult problem that this field hopes to solve. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes a solution that can not only safely recover coal seams above the critical elevation of water diversion but also prevent multiple complex medium water from entering the mining area. Specifically, the present invention proposes a method for preventing and controlling multiple complex medium water in shallow buried coal seams, comprising the following steps:

[0005] S1: Determine the outcrop range of the coal seam, and do not mine the coal in the outcrop range; in the floor rock layer, dig a return air tunnel along the direction of the coal seam below the outcrop, and dig a transportation tunnel on the side of the coal seam below the return air tunnel;

[0006] S2: Determine the total content of water in multiple complex media within the mining area; determine the amount of water available per unit area of ​​goaf after coal seam mining, and then determine the minimum goaf area required for water storage;

[0007] S3: Several L-shaped coal mining faces are arranged from left to right along the strike of the mining area, each L-shaped coal mining face includes a strike-arranged portion and a dip-arranged portion, the strike-arranged portion of the several L-shaped coal mining faces are arranged from deep to shallow, and the dip-arranged portion is arranged from left to right, and the stop mining line position of the dip-arranged portion is the critical elevation of water diversion; the number of the L-shaped coal mining faces satisfies that the goaf area after mining is not less than the minimum goaf area for water storage;

[0008] S4: For the first L-shaped coal mining face, a return air stone gate is constructed from the return air main tunnel to the coal seam, and a transport stone gate is constructed from the transport main tunnel to the coal seam. The return air stone gate is used to construct a section return air tunnel in the coal seam, and the transport stone gate is used to construct a section transport tunnel in the coal seam. The first L-shaped coal mining face is mined to the stop mining line;

[0009] The section return air lane of the first L-shaped coal mining face is used as the section transport lane of the next L-shaped coal mining face and a transport stone gate is excavated to connect with the transport main lane. A return air stone gate is constructed from the return air main lane to the coal seam. A section return air lane is constructed from the return air stone gate in the coal seam to mine the second L-shaped coal mining face to the stop mining line.

[0010] And so on, until all L-shaped coal mining faces are mined;

[0011] S5: Drainage boreholes are constructed from the surface to the goaf produced by mining in the L-shaped coal mining face. The drainage boreholes are constructed using bare holes, without casing in stable formation areas, and with flower pipes in unstable formation areas, so that all the multiple complex media water in the mining area is discharged into the goaf;

[0012] S6: In the mining area, a water-proof coal pillar is left at the boundary of the goaf. For the unmined area, several rectangular coal mining faces are arranged along the strike and along the dip. The rectangular coal mining faces are mined in sequence, and each rectangular coal mining face is mined from deep to shallow.

[0013] Preferably, in step S1, the coal seam outcrop includes a burnt area and a coal body that is affected by weathering and has little mining value.

[0014] Preferably, in step S1, the range of the loosening zone generated after the excavation of the transport tunnel and the return air tunnel is determined, and the loosening zone of the return air tunnel does not touch the coal seam outcrop and the loosening zone of the transport tunnel.

[0015] Preferably, the multiple complex medium water includes any two or more of surface water, loose layer water, weathered bedrock water, coal seam outcrop burn zone water, and rainy season precipitation.

[0016] Preferably, in step S6, the stop mining line of each rectangular working face directly reaches the outcrop boundary of the coal seam; the width of the rectangular coal mining working face is consistent with the width of the L-shaped coal mining working face.

[0017] Preferably, the method further includes step S7: restoring the surface water system and the loose layer water system, and returning the existing water thereto through the water storage in the goaf.

[0018] The beneficial effects of the present invention are as follows: the present invention arranges the transport tunnel and the return air tunnel in the shallow bottom rock layer of the mining area for the multiple complex medium water conditions of the shallow buried coal seam, and connects with the section tunnel through the stone gate, so as to ensure the stability of the tunnel; the concept of critical water conduction elevation is proposed, and a water storage goaf can be formed by arranging an L-shaped coal mining face below the critical water conduction elevation, and it is not affected by multiple complex medium water during the mining period; then the multiple complex medium water is discharged into the water storage goaf, so as to solve the problem of safe mining of the remaining coal seams in the mining area, especially the coal seams above the critical water conduction elevation; the remaining coal seams in the mining area are mined by rectangular coal mining faces; the arrangement of water-isolating coal pillars between the L-shaped coal mining face and the rectangular coal mining face can avoid the water discharged into the goaf from affecting the mining of the rectangular face. In addition, the rectangular coal mining face adopts inclined mining, and even if there is a problem of incomplete drainage of the drainage borehole, when water enters the rectangular face, it will flow to the goaf behind the rectangular coal mining face, which has little impact on the safe mining of the rectangular face. The present invention can solve the problem of safe recovery of shallow coal seams by multiple complex medium water, and can improve the coal recovery rate to the maximum extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional schematic diagram of the shallow coal seam multiple complex medium water control method of the present invention;

[0020] Figure 2 It is a schematic plan view of the shallow coal seam multi-complex medium water prevention method before coal seam mining according to the present invention;

[0021] Figure 3 It is a schematic diagram of the plan view of the coal seam mining process of the shallow coal seam multiple complex medium water prevention method of the present invention;

[0022] In the figure, loose layer-1; overlying rock layer-2; coal seam-3; coal seam outcrop-31; bottom rock layer-4; return air main tunnel-5; return air stone gate-6; transport main tunnel-7; transport stone gate-8; section transport tunnel-9; section return air tunnel-10; water diversion critical elevation-11; drainage borehole-12; goaf-13; coal mining working face-14; water-proof coal pillar-15. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] like Figure 1-3As shown, the method for preventing and controlling multiple complex media water in shallow coal seams of the present invention is specifically applied in a certain shallow coal seam mining area (or pan area), which is affected by multiple complex media waters such as surface water (not shown in the figure), loose layer water in the loose layer 1, weathered bedrock water at the top of the overlying rock layer 2, water in the burnt area at the coal seam outcrop 31 of the coal seam 3, and precipitation in the rainy season. First, the water-conducting critical elevation 11 of the coal seam is determined by actual measurement and theoretical calculation. When mining the coal seam 3 above the water-conducting critical elevation 11, the water-conducting fracture zone will penetrate the weathered bedrock water, loose layer water and surface water; when mining the coal seam 3 below the water-conducting critical elevation 11, the water-conducting fracture zone will not develop to the entire bedrock, that is, it will not penetrate the weathered bedrock water, loose layer water and surface water; but if only mining the coal seam 3 below the water-conducting critical elevation 11, it will cause a waste of coal resources. In this regard, the present invention proposes a solution that can safely recover coal seams 3 above the critical water diversion elevation 11 and prevent multiple complex medium water from entering the mining area. Specifically, the shallow buried coal seam multiple complex medium water prevention method of the present invention includes the following steps:

[0025] S1: Determine the range of the coal seam outcrop 31, which includes the burnt area and the coal body with little mining value due to weathering; the coal body within the range of the coal seam outcrop 31 will not be mined; determine the range of the loose zone (or plastic zone) generated after the transportation tunnel 5 and the return air tunnel 7 are excavated; in the floor rock layer 4, the return air tunnel 5 is excavated along the coal seam direction at the lower part of the coal seam outcrop 31, and the transportation tunnel 7 is excavated at the lower part of the return air tunnel 5 on the side of the coal seam 3, wherein the loose zone of the return air tunnel 5 does not touch the loose zone of the coal seam outcrop 31 and the transportation tunnel 7;

[0026] S2: Determine the total content of water in multiple complex media within the mining area, including surface water, loose layer water, weathered bedrock water, coal seam outcrop fire zone water, and rainy season precipitation; the surface water system here should be a small surface water system. If it is a large surface water system, it should be mined with a protective coal pillar in accordance with the "Coal Mining Regulations";

[0027] After the coal seam 3 is mined, the upper rock layer collapses to form a goaf. The goaf contains collapsed broken rock blocks with gaps between them, which is a good space for water storage. In the prior art, goafs are often used to build underground reservoirs; therefore, the present invention uses goafs as water storage spaces to store multiple complex medium water. First, determine the amount of water that can be provided per unit area of ​​the goaf 13 after the coal seam 3 is mined, and then determine the minimum goaf area required for water storage based on the total content of multiple complex medium water within the mining area (the total content of multiple complex medium water within the mining area divided by the amount of water that can be provided per unit area of ​​the goaf is equal to the minimum goaf area for water storage);

[0028] S3: Several L-shaped coal mining faces 14 are arranged in sequence from left to right along the strike of the mining area, and each L-shaped coal mining face 14 includes a strike arrangement portion and a dip arrangement portion, wherein the strike arrangement portions of several L-shaped coal mining faces 14 are arranged in sequence from deep to shallow, and the dip arrangement portions of several L-shaped coal mining faces 14 are arranged in sequence from left to right, and the shallowest position of the dip arrangement portion (mining stop line position) is the critical elevation 11 of water diversion; that is, the leftmost dip arrangement portion and the deepest strike arrangement portion constitute the first coal mining face 14 (① in the figure); the second dip arrangement portion on the left and the second deepest strike arrangement portion constitute the second coal mining face 14 (② in the figure), and so on; the number of the L-shaped coal mining faces 14 satisfies that the area of ​​the goaf 13 after mining is not less than the minimum goaf area for water storage;

[0029] S4: For the first L-shaped coal mining face, a return air stone gate 6 is constructed from the return air main tunnel 5 to the coal seam 3, and a transport stone gate 8 is constructed from the transport main tunnel 7 to the coal seam 3. A section return air tunnel 10 is constructed from the return air stone gate 6 in the coal seam 3 along the coal seam bottom plate, and a section transport tunnel 9 is constructed from the transport stone gate 8 in the coal seam 3 along the coal seam bottom plate, wherein the section transport tunnel 9 is on the left and deep, and the section return air tunnel 10 is on the right and at the bottom, and the first L-shaped coal mining face is mined to the stop mining line (critical water diversion elevation 11);

[0030] The section return air lane 10 of the first L-shaped coal mining face 14 is used as the section transport lane 9 of the next L-shaped coal mining face 14, and the transport stone gate 8 is excavated to connect with the transport main lane 7, and the return air stone gate 6 is constructed from the return air main lane 5 to the coal seam 3, and the section return air lane 10 is constructed along the coal seam bottom plate in the coal seam 3 from the return air stone gate 6, wherein the section transport lane 9 is on the left and deep, and the section return air lane 10 is on the right and at the bottom, and the second L-shaped coal mining face 14 is mined to the stop mining line (critical water diversion elevation 11);

[0031] And so on, until all L-shaped coal mining working faces 14 are mined;

[0032] S5: Drainage boreholes 12 are constructed from the surface to the goaf 13 produced by mining the L-shaped coal mining face 14. The drainage boreholes 12 are constructed by bare holes, without casing in the stable formation area, and with flower pipes in the unstable formation area, so that all the multiple complex medium water in the mining area is discharged into the goaf 13; in this way, other coal mined in the mining area does not need to worry about the influence of the part arranged along the inclination;

[0033] S6: In the mining area, a water-proof coal pillar 15 is left at the boundary of the goaf 13. For the unmined area, a number of rectangular coal mining faces 14 are arranged from right to left, and the stop mining line of each rectangular coal mining face reaches the boundary of the coal seam outcrop 31; the width of the rectangular coal mining face 14 is consistent with the width of the L-shaped coal mining face 14; the rectangular coal mining faces 14 are mined from right to left or from left to right; for each rectangular coal mining face 14, mining is carried out from deep to shallow.

[0034] S7: Restore the surface water system and the loose layer water system, and return the existing water to them through the water storage in the goaf 13.

[0035] Of course, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It should be noted that all equivalent substitutions and obvious deformation forms made by any technician familiar with the field under the guidance of this specification fall within the essential scope of this specification and should be protected by the present invention.

Claims

1. A method for preventing and controlling water in multiple complex media in shallow coal seams, characterized in that: The steps include: S1: Determine the outcrop range of the coal seam, and do not mine the coal in the outcrop range; in the floor rock layer, dig a return air tunnel along the direction of the coal seam below the outcrop, and dig a transportation tunnel on the side of the coal seam below the return air tunnel; S2: Determine the total content of water in multiple complex media within the mining area; determine the amount of water available per unit area of ​​goaf after coal seam mining, and then determine the minimum goaf area required for water storage; S3: Several L-shaped coal mining faces are arranged from left to right along the strike of the mining area, each L-shaped coal mining face includes a strike-arranged portion and a dip-arranged portion, the strike-arranged portion of the several L-shaped coal mining faces are arranged from deep to shallow, and the dip-arranged portion is arranged from left to right, and the stop mining line position of the dip-arranged portion is the critical elevation of water diversion; the number of the L-shaped coal mining faces satisfies that the goaf area after mining is not less than the minimum goaf area for water storage; S4: For the first L-shaped coal mining face, a return air stone gate is constructed from the return air main tunnel to the coal seam, and a transport stone gate is constructed from the transport main tunnel to the coal seam. The return air stone gate is used to construct a section return air tunnel in the coal seam, and the transport stone gate is used to construct a section transport tunnel in the coal seam. The first L-shaped coal mining face is mined to the stop mining line; The section return air lane of the first L-shaped coal mining face is used as the section transport lane of the next L-shaped coal mining face and a transport stone gate is excavated to connect with the transport main lane. A return air stone gate is constructed from the return air main lane to the coal seam. A section return air lane is constructed from the return air stone gate in the coal seam to mine the second L-shaped coal mining face to the stop mining line. And so on, until all L-shaped coal mining faces are mined; S5: Drainage boreholes are constructed from the surface to the goaf produced by mining in the L-shaped coal mining face. The drainage boreholes are constructed using bare holes, without casing in stable formation areas, and with flower pipes in unstable formation areas, so that all the multiple complex media water in the mining area is discharged into the goaf; S6: In the mining area, a water-proof coal pillar is left at the boundary of the goaf. For the unmined area, several rectangular coal mining faces are arranged along the strike and along the dip. The rectangular coal mining faces are mined in sequence, and each rectangular coal mining face is mined from deep to shallow.

2. The shallow coal seam multi-complex medium water control method according to claim 1 is characterized in that: In step S1, the coal seam outcrop includes a burnt area and a coal body with little mining value due to weathering.

3. The shallow coal seam multi-complex medium water control method according to claim 1 is characterized in that: In step S1, the range of the loosening circle generated after the excavation of the transport tunnel and the return air tunnel is determined, and the loosening circle of the return air tunnel does not touch the coal seam outcrop and the loosening circle of the transport tunnel.

4. The shallow coal seam multi-complex medium water control method according to claim 1 is characterized in that: The multiple complex medium water includes any two or more of surface water, loose layer water, weathered bedrock water, coal seam outcrop burn area water, and rainy season precipitation.

5. The shallow coal seam multi-complex medium water control method according to claim 1 is characterized in that: In step S6, the stop mining line of each rectangular working face directly reaches the outcrop boundary of the coal seam; the width of the rectangular coal mining working face is consistent with the width of the L-shaped coal mining working face.

6. The shallow coal seam multi-complex medium water control method according to claim 1 is characterized in that: The method also includes step S7: restoring the surface water system and the loose layer water system, and returning the existing water thereto through the water storage in the goaf.

Images