A mining method for isolated working face of near-horizontal coal seam in rock burst mine

Abstract

The present invention discloses a mining method for an isolated working face of a near-horizontal coal seam in a rock burst mine, specifically, setting large boundary coal pillars on both sides of the goaf and the edge of the isolated working face; mining multiple strip mining areas along the inclination of the solid coal body area within the isolated working face, setting a residual strip coal pillar between each two strip mining areas, and setting a small boundary coal pillar between one end of each strip mining area and the goaf; opening multiple pressure relief holes on the outer coal wall of the boundary large coal pillar; cement walling the strip mining area, and filling the inside of the cement wall, and sealing the cement wall after the filling is completed; after the strip mining area is filled, the strip residual coal pillars are sequentially mined. Since the width of the strip mining area is small, the roof of the strip goaf area does not need to be collapsed, minimizing the disturbance to the mine roof and the overlying rock layer, thereby achieving the purpose of green and safe mining working face.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining and mine safety, and in particular relates to a mining method for an isolated island working face of a nearly horizontal coal seam in a rock burst mine. Background Art

[0002] An island face refers to a working face where the working face to be mined is surrounded by goafs, or where both sides of the working face drift are surrounded by goafs. Coal mining within this type of face is called "island" face mining. During the mining process, the combined effects of the dynamic pressures of the adjacent goafs and working face can easily induce rock burst disasters. However, if rock burst mines retain island faces without mining, a large amount of coal resources will be wasted, resulting in economic losses for the mine. Therefore, exploring reasonable mining methods and rock burst prevention and control measures to solve the problem of safe mining of island faces in rock burst mines is of great significance to ensuring normal mine safety and production. Summary of the Invention

[0003] The purpose of the present invention is to provide a mining method for an isolated island working face in a near-horizontal coal seam in a rock burst mine, and to provide a solution to the problem of increased risk of tunnel impact caused by large-scale collapse of the pressure-bearing overall roof of the isolated island working face during mining.

[0004] The technical solution adopted by the present invention is a method for mining an isolated working face of a near-horizontal coal seam in a rock burst mine, which is specifically implemented according to the following steps:

[0005] Step 1: setting a large boundary coal pillar a on one side of the edge between the goaf and the isolated working face; leaving a large boundary coal pillar b on the other side of the edge between the goaf and the isolated working face;

[0006] Step 2: strip mining is carried out inside the isolated working face of the nearly horizontal coal seam; specifically:

[0007] In the solid coal area within the isolated working face, multiple strip mining areas are mined every 6m to 7m using a continuous coal miner. The strip mining areas near the two edges are 30m away from both edges of the goaf. A residual strip coal pillar is set between each two strip mining areas. A small boundary coal pillar with a width of 6m to 8m is set between one end of each strip mining area and the goaf.

[0008] Step 3: Open multiple pressure relief holes on the outer coal walls of the boundary large coal pillar a and the boundary large coal pillar b;

[0009] Step 4: Concrete walls are built in the strip coal mining area, and the interior of the cement walls is filled. After the filling is completed, the cement walls are sealed;

[0010] Step 5: After the strip mining area is filled, the strip remaining coal pillars are mined in sequence.

[0011] The present invention is also characterized in that:

[0012] In step 1, the width and length of the boundary large coal pillar a and the boundary large coal pillar b are the same; the width of the boundary large coal pillar a is 30m to 35m.

[0013] In step 2, the width of the strip mining area is 6 to 7 meters, and the length of the strip mining area is less than the strike length of the isolated working face; the width of the remaining strip coal pillar is the distance between the two strip mining areas; the length of the remaining strip coal pillar is consistent with the length of the strip mining area.

[0014] In step 3, the pressure relief holes are perpendicular to the coal wall, with a height of 1 to 1.5 m, a spacing of 1 to 2 m between each two pressure relief holes, and a hole depth of 20 to 25 m.

[0015] In step 4, during filling, the filling body is a paste; the width of the cement wall is 0.3 to 0.5 m.

[0016] The beneficial effect of the present invention is that strip mining is adopted for the isolated working face, and a large boundary coal pillar is set at the edge of the working face goaf, and the large boundary coal pillar is relieved through pressure relief holes to reduce the risk of impact on the tunnel caused by the lateral support pressure of the goaf; after the mining is completed, the strip void is filled and the remaining coal pillar is continued to be mined to achieve the purpose of completely mining the isolated working face. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of mining and setting coal pillars in a mining method for an isolated island working face in a near-horizontal coal seam in a rock burst mine according to the present invention;

[0018] Figure 2 It is a schematic diagram of an isolated working face in a method for mining an isolated working face in a near-horizontal coal seam in a rock burst mine according to the present invention;

[0019] Figure 3 This is a schematic diagram of strip filling in the coal mining area in a method for mining an isolated island working face in a near-horizontal coal seam in a rock burst mine according to the present invention;

[0020] Figure 4 This is a schematic diagram of recovering residual coal pillars in a mining method for an isolated island working face in a near-horizontal coal seam in a rock burst mine according to the present invention;

[0021] In the figure: 1. Isolated working face; 2. Goaf; 3. Small coal pillar at the boundary; 4. Strip mining area; 5. Large coal pillar at the boundary a; 6. Large coal pillar at the boundary b; 7. Remaining strip coal pillar. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The present invention provides a method for mining an isolated island working face of a near-horizontal coal seam in a rock burst mine, which is specifically implemented according to the following steps:

[0024] Step 1, such as Figure 1 and Figure 2 As shown, a large boundary coal pillar a5 is set on one side of the edge of the goaf 2 and the isolated working face 1; a large boundary coal pillar b6 is left on the other side of the edge of the goaf 2 and the isolated working face 1;

[0025] The width and length of the boundary large coal pillar a5 and the boundary large coal pillar b6 are the same;

[0026] Due to the influence of the lateral support pressure of the goaf, there is a high stress peak area in the coal body 4 to 13 meters away from the edge of the goaf. Therefore, a large coal pillar with a width of 30 to 35 meters is left. When the continuous miner mines the coal body on the side of the goaf, a large coal pillar with a width of 30 to 35 meters is left between the goaf and the island working face.

[0027] Step 2: strip mining is carried out inside the isolated island working face 1 of the nearly horizontal coal seam;

[0028] Specifically, a continuous coal mining machine is used to mine multiple strip mining areas 4 every 6 to 7 meters in the solid coal area of ​​the isolated working face 1. The strip mining areas 4 near the two edges are 30 meters away from the two edges of the goaf 2. The width of the strip mining area 4 is 6 to 7 meters, and the length of the strip mining area 4 is less than the strike length of the working face. The coal body is mined in strips, and a residual strip coal pillar 7 is set between each two strip mining areas 4. The width of the residual strip coal pillar 7 is the distance between the two strip mining areas 4; the length of the residual strip coal pillar 7 is the same as the length of the strip mining area 4. A small boundary coal pillar 3 with a width of 6 to 8 meters is set between one end of each strip mining area 4 and the goaf 2, thereby isolating it from the goaf 2.

[0029] Between the strip mining area 4 and the goaf 2 is the boundary large coal pillar a5, and similarly on the other side is the boundary large coal pillar b6;

[0030] The calculation formula for the number of remaining strip-shaped coal pillars 4 is c = (d-2*e) / 2;

[0031] Among them, c is the number of remaining strip coal pillars 4, in units of pieces; d is the width of the isolated working face, in meters; e is the width of the boundary large coal pillar, in meters;

[0032] Step 3: Open multiple pressure relief holes on the outer coal walls of the boundary large coal pillars a5 and b6;

[0033] The pressure relief holes are perpendicular to the coal wall, and the angle is determined according to the angle of the coal seam. The height is 1 to 1.5 meters, the distance between each two pressure relief holes is 1 to 2 meters, and the hole depth is 20 to 25 meters, so as to reduce the risk of impact of the remaining strip coal pillars.

[0034] Step 4, cement walling is carried out in the strip coal mining area 4, such as Figure 3 and Figure 4 As shown, the interior of the cement wall is filled, and after the filling is completed, the cement wall is sealed;

[0035] The filling body is paste filling, which can use cement as a binder, mixed with coal gangue, fly ash, etc. and water on the ground to form a 78%-82% paste slurry; the cement wall is rectangular with a width of 0.3-0.5m;

[0036] Step 5: After the strip mining area 4 is filled, the strip residual coal pillars 7 are mined in sequence.

[0037] Example

[0038] The isolated working face of a nearly horizontal coal seam with an inclined length of 320m, a strike length of 2000m, a buried depth of 600m and a coal seam thickness of 4m was mined.

[0039] The continuous miner opens at the tunnel entrance, 30 meters from the goaf boundary. A strip mining area 1994 meters long and 6-7 meters wide is mined along the strike of the working face, leaving small boundary pillars at the ends of the strip mining area and the edge of the goaf. The same process is repeated to mine another strip mining area at intervals of 6-7 meters. Pressure relief holes are drilled perpendicular to the coal wall, 1-1.5 meters above the floor, 1-2 meters apart, and 20-25 meters deep.

[0040] Mining a strip coal mining area, the length a of the strip coal mining area is less than 2000m, the width b is 6m, and the number of remaining strip coal pillars is c, where c = (d-2*e) / 2. c is the number of remaining strip coal pillars, d is the width of the isolated working face, 320m; e is the width of the boundary large coal pillar, which is 30m. The calculated number c = 130.

[0041] When mining a strip mining area, mining can be carried out from both ends of the mining area to the middle area in sequence. After a strip mining area is mined, a 6m boundary coal pillar is left to separate the goaf.

[0042] After the first strip mining area is mined, a second strip mining area is mined at intervals of the same width, and the same mining steps are followed. When mining the second strip mining area, the first strip mining area is backfilled. First, a 0.3-0.5m cement wall is built at the edge of the goaf in the mining area, and then the interior of the wall is filled with paste. After the backfill is complete, the wall is sealed. After the last strip mining area is filled, the remaining strip coal pillars are mined. The mining sequence can be from the outermost remaining coal pillars to the middle remaining coal pillars, or mining can be carried out sequentially.

Claims

1. A method for mining an isolated working face of a near-horizontal coal seam in a rock burst mine, characterized in that: Please follow the steps below to implement it: Step 1: setting a large boundary coal pillar a on one side of the edge between the goaf and the isolated working face; leaving a large boundary coal pillar b on the other side of the edge between the goaf and the isolated working face; The width and length of the boundary large coal pillar a and the boundary large coal pillar b are the same; the width of the boundary large coal pillar a is 30m~35m; Step 2: strip mining is carried out inside the isolated working face of the nearly horizontal coal seam; specifically: In the solid coal area within the isolated working face, a continuous coal miner is used to mine multiple strip mining areas every 6m to 7m. The strip mining areas near the two edges are 30m away from the two edges of the goaf. A residual strip coal pillar is set between each two strip mining areas. A small boundary coal pillar with a width of 6m to 8m is set between one end of each strip mining area and the goaf. The width of the strip mining area is 6-7m, and the length of the strip mining area is less than the strike length of the isolated working face; the width of the remaining strip coal pillar is the distance between the two strip mining areas; the length of the remaining strip coal pillar is the same as the length of the strip mining area; Step 3: Open multiple pressure relief holes on the outer coal walls of the boundary large coal pillar a and the boundary large coal pillar b; Step 4: Concrete walls are built in the strip coal mining area, and the interior of the cement walls is filled. After the filling is completed, the cement walls are sealed; Step 5: After the strip coal mining area is filled, the remaining strip coal pillars are mined in sequence.

2. The method for mining an isolated island working face in a near-horizontal coal seam in a rock burst mine according to claim 1, characterized in that: In step 3, the pressure relief holes are perpendicular to the coal wall, with a height of 1-1.5 m, a distance of 1-2 m between each two pressure relief holes, and a hole depth of 20-25 m.

3. The method for mining an isolated island working face in a near-horizontal coal seam in a rock burst mine according to claim 1, characterized in that: In step 4, during filling, the filling body is a paste; the width of the cement wall is 0.3-0.5m.

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