A method for controlling top coal mining in thick coal seams with old empty lanes through roof slabs

Abstract

The present invention discloses a method for top-controlled mining of thick coal seams through old empty tunnels on the roof, and relates to the technical field of coal mining. Taking the roof of a thick coal seam that is parallel to the working face as an example, first, when the mining of the working face is about to have a mining impact on the empty tunnel, the working face is gradually tilted to a certain angle, so that when the working face is advanced to the bottom of the old empty tunnel, it can be out of plane with the empty tunnel and form a small-scale projected overlapping area; then, as the working face advances, the overlapping position continues to change, and before each change of the overlapping area, the empty tunnel at the next overlap is filled with high-water material, so that the empty tunnel that was originally deformed or even collapsed forms a relatively stable structure, providing a load foundation for the hydraulic support that is about to be pushed over. Finally, the working face is then advanced until the working face completely passes through the empty tunnel on the roof and gradually returns to the right position. The method of the present invention achieves the most effective control effect of the old empty tunnel on the roof with the simplest and most economical measures, while ensuring safe production.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, in particular to a method for re-mining and top-controlled coal mining in thick coal seams in old empty lanes through roof plates. Background Art

[0002] During mine production, the use of tunnels for mining, changes in mine mining design, or the advanced arrangement of exploration tunnels will all lead to empty tunnels during the advancement of the working face. This is especially true when re-mining thick coal seams and an old empty tunnel appears above the working face. When the working face passes under this old empty tunnel on the roof, the old empty tunnel is greatly affected by mining, and the surrounding rock morphology in the old empty tunnel is unknown. If the empty tunnel has already experienced large-scale spalling and roof collapse, the fallen roof will crush the support, affecting production safety. Therefore, the problem of safe and efficient re-mining of the working face through the empty tunnel on the roof needs to be solved urgently. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for re-mining and controlling the top of thick coal seams through old empty lanes with roofs. The method mainly adopts a combination of "working face roof control and working face inclination adjustment technology" to achieve the most effective control effect of old empty lanes with the simplest and most economical measures, while ensuring safe production.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for re-mining and top-controlled coal mining in thick coal seams with old empty lanes through roof slabs comprises the following steps in sequence:

[0006] a. Tilt adjustment, including the following sub-steps:

[0007] a1. The working face is divided into the first target position, the second target position, the third target position and the fourth target position in sequence when passing under the old empty roadway located at the roof;

[0008] The first target position is the position of the working face when it is 4 to 6 times the width of the old empty roadway from the roof;

[0009] The second target position is the working face position when the horizontal distance between the working face and the empty roadway is zero or close to zero;

[0010] The third target position is the position of the working face when the working face just completely passes through the roof old empty lane and there is no overlapping area between the working face and the old empty lane;

[0011] The fourth target position and the first target position are symmetrically distributed about the old empty lane;

[0012] a2. When the coal mining face is at the first target position, gradually tilt the face to a certain angle. The specific steps are as follows:

[0013] Step 1: When the working face is at the first target position and a new cycle of operation begins, the cutter is advanced at the end of the working face (①) and the frame is moved forward. The coal cutting depth and frame moving distance are controlled to be the rated cutting depth of the coal shearer. The hydraulic support at the other end of the working face (②) does not move, and an idle cut is performed when the coal shearer runs to the end (②).

[0014] Step 2: Connect the hydraulic supports at both ends with steel wire ropes and tighten the steel wire ropes. When performing the first coal cutting operation, push the remaining hydraulic supports to the steel wire ropes and stop. After completing one coal cutting operation, the working surface will complete a small angle adjustment and keep the working surface shape straight.

[0015] Step 3: When the second coal cutting operation is carried out, the shearer is located at the end of the working face ② and performs dry cutting. At the same time, the frame is advanced at the end of the working face ①. The frame is moved forward by the rated cutting depth of the shearer. When the shearer reaches this point, it is required to cut coal at the rated cutting depth. The wire ropes connecting the hydraulic supports at both ends are kept taut. When the second coal cutting operation is carried out, the remaining hydraulic supports are advanced to the wire rope position and then stopped.

[0016] Step 4: Repeat steps 1 to 3 for each feed, accumulate the angle of the cutter's tilt adjustment each time, and require the coal mining face to reach the required tilt adjustment angle before reaching the second target position, until the coal mining face reaches the second target position;

[0017] b. Filling

[0018] The filling step is the process of the working face moving from the second target position to the third target position. When the coal mining working face advances to the range of this stage, the drill holes in the empty roadway at the overlapping area of the small-scale projection that will be formed are filled with high-water materials, and the current inclination angle is maintained to continue advancing the working face.

[0019] c. Return to normal

[0020] The return step is the process of advancing the working surface from the third target position to the fourth target position;

[0021] When the working face is at the third target position, the working face is gradually straightened and the normal coal mining process of cutting coal → moving the frame → moving the conveyor is restored.

[0022] As a preferred embodiment of the present invention, the step c comprises the following sub-steps:

[0023] c1. When the working face is at the third target position, in a new cycle of operation, the hydraulic support is not moved at the working face end ①. The shearer performs dry cutting at this point. The support is advanced at the working face end ②. The support is moved forward by the rated cutting depth of the shearer. When the shearer reaches this position, it is controlled to cut coal at the rated cutting depth.

[0024] c2. Connect the hydraulic supports at both ends with steel wire ropes and tighten the steel wire ropes. When the first coal cutting operation of the shift is carried out, push the remaining hydraulic supports to the steel wire ropes and stop. After each coal cutting operation, the working surface is straightened at a small angle and the working surface shape is kept straight.

[0025] c3. During the second coal cutting operation of the shift, the shearer is located at the end of the working face at position ② and advances the coal cutting and moves the support. The coal cutting depth and the support moving distance are both the rated cutting depth of the shearer. The hydraulic support at the end of the working face at position ① is not moved, and the shearer is required to perform a dry cut when it reaches this position. The wire ropes connecting the hydraulic supports at both ends are kept taut. When the second coal cutting operation is carried out, the remaining hydraulic supports are advanced to the wire rope position and then stopped.

[0026] c4. Repeat operations c1 to c3 each time the tool is fed, accumulate the angle of the inclination adjustment each time, and control the coal mining working face to reach the required inclination adjustment angle before reaching the second target position, until the coal mining working face reaches the fourth target position.

[0027] As another preferred embodiment of the present invention, the high-water material includes material A and material B, wherein material A is mainly based on sulfoaluminate cement clinker, mixed with corrosion inhibitors and coagulants, and material B includes lime, gypsum, suspending agent and composite rapid-setting and early-strength agent.

[0028] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0029] (1) By adjusting the working face to an angle and passing through the old empty roadway on the roof, compared with the normal advancement of the working face through the old empty roadway on the roof, it is possible to avoid the situation where most or even all of the hydraulic supports on the working face are subjected to the load of the old empty roadway on the roof, which may cause most of the hydraulic supports to be crushed to death.

[0030] (2) By adjusting the working face to an angle and passing through the old empty tunnels on the roof, only the empty tunnels and their surrounding rocks in the small-scale overlapping area to be formed are drilled and filled with high-water materials, thus avoiding the blind filling of the old empty tunnels on the roof, saving materials and making the filling more economical.

[0031] (3) After the working face is tilted, each process is equivalent to a preview of the filling effect. If this process can ensure the safety of the working face, the filling experience of this process can be referred to when the next process is carried out, thus ensuring the safety of each process and finally passing through the old empty tunnel on the top plate safely.

[0032] (4) The present invention uses high-water-density materials as filling materials in the mine goaf in the reinforcement technology of the roof old empty tunnels. It not only has high short-term strength and good reinforcement effect, but also consolidates quickly without delaying production.

[0033] (5) First, the purpose of adjusting the working face in the present invention is to ensure safe production of the working face and prevent mine pressure accidents, so the working face is adjusted to make it obliquely intersect with the old empty tunnel to reduce the empty roof area of the support; secondly, the present invention requires a smaller adjustment angle and requires it to return to the center after passing the empty tunnel, without considering the increase or decrease in the number of hydraulic supports, and without changing the shape of the return air chute. The process of passing the empty tunnel is simple and the construction is convenient; finally, the working face of the present invention can be adjusted while advancing to ensure normal production of the working face; while the purpose of adjusting the working face in the prior art is to mine the triangular coal next to the boundary coal pillar of the mine, which belongs to the same level and does not consider the safety of the working face roof; secondly, the angle of adjusting the working face in the prior art is more arbitrary, and the adjustment method always keeps the working face from advancing and adjusts the angle in place; finally, the adjustment method in the prior art adopts a forward-moving method to mine the corner coal, which requires filling beside the tunnel, is complex in construction, and ventilation of the working face is difficult. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings:

[0035] Figure 1 This is a schematic diagram of the first target position of the working surface of the present invention;

[0036] Figure 2 This is a schematic diagram of the general position of the working surface during the tilt adjustment stage;

[0037] Figure 3 This is a schematic diagram of the second target position and the first filling of the working surface;

[0038] Figure 4 This is the general position of the working face during the filling stage and the schematic diagram of the second filling;

[0039] Figure 5 This is the general position of the working face during the filling stage and the schematic diagram of the third filling;

[0040] Figure 6 The third target position and filling diagram of the working surface;

[0041] Figure 7 This is a schematic diagram of the general position and filling of the working surface during the return stage;

[0042] Figure 8 The fourth target position and filling diagram of the working surface;

[0043] Figure 9 It is the vertical cross-section of the third target position of the working surface;

[0044] In the picture:

[0045] 1-Goaf; 2-Fully-mechanized mining equipment on the coal mining face; 3-Old goaf roadway on the roof; 4-Solid coal; 5-First filling area, 6-Second filling area. DETAILED DESCRIPTION

[0046] The present invention proposes a method for top-controlled coal mining in thick coal seams with old empty lanes through the roof. In order to make the advantages and technical solutions of the present invention clearer and more specific, the present invention is further described below in conjunction with specific embodiments.

[0047] like Figure 4 As shown, there are shown the goaf 1, the fully mechanized mining equipment 2 of the coal mining face, the old empty roadway 3 of the roof, the solid coal 4, the first filling area 5 and the second filling area 6.

[0048] The high-water-density materials described in this invention include Material A and Material B. Material A is primarily based on sulfoaluminate cement clinker, mixed with a corrosion inhibitor and a coagulant. Material B includes lime, gypsum, a suspending agent, and a composite rapid-setting and early-strength admixture. The raw materials for the high-water-density materials can be purchased commercially.

[0049] The first target position mentioned in the present invention is the position of the working face when it is 4 to 6 times the width of the old empty tunnel away from the top plate; the second target position is the position of the working face when the horizontal distance between the working face and the empty tunnel is zero or close to zero; the third target position is the position of the working face when the working face just passes through the old empty tunnel on the top plate and there is no overlapping area between the working face and the old empty tunnel; the fourth target position and the first target position are symmetrically distributed about the old empty tunnel.

[0050] The present invention will be described in detail below with reference to specific embodiment 1.

[0051] Example 1:

[0052] The top-controlled mining method for re-mining thick coal seams in old empty lanes through the roof includes the following parts:

[0053] When the working face passes through the old empty roadway with a length of L = 120m and a width of B = 5m, it will go through Figure 1 、 Figure 3 、 Figure 6 、 Figure 8 The four target positions shown in 2 in the figure are divided into three stages: tilt adjustment stage, filling stage, and return stage.

[0054] 1. Tilt adjustment stage:

[0055] The tilting stage is when the working face changes from Figure 1 The middle working surface position is advanced to Figure 3 The process of determining the working surface position.

[0056] The coal mining face is in Figure 1At the position shown in 2, the horizontal distance between the working face and the roof old empty roadway is A=4×B~6×B=20~30m. In this embodiment, A=25m is taken. The working face is gradually tilted to a certain angle. In the case of two cuts per shift, the implementation steps of tilting are as follows:

[0057] Step 1: When the working surface is at the first target position and a new cycle of operation begins, Figure 1 As shown, at the end of the working face ①, the cutter is advanced and the frame is moved forward. The frame moving distance is 0.8m of the rated cutting depth of the coal shearer. At the other end of the working face ②, the hydraulic support is not moved. When the coal shearer runs to the end ②, an empty cut is performed.

[0058] Step 2: Connect the hydraulic supports at both ends with steel wire ropes and tighten the steel wire ropes. When the first coal cutting operation is carried out, push the remaining hydraulic supports to the steel wire ropes and stop. In this way, the angle of each cut is θ0 = arctan (0.8 / 120) = 0.38°. The general position of the working face in the tilting stage is as follows: Figure 2 2 in ;

[0059] Step 3: When the second coal cutting operation is carried out, the shearer is located at end ② and performs dry cutting. When it is at end ①, the frame is advanced to the rated cutting depth of 0.8m for the shearer. When the shearer reaches this point, it cuts coal at the rated cutting depth. The wire ropes connecting the hydraulic supports at both ends are kept taut. When the second coal cutting operation is carried out, the remaining hydraulic supports are pushed to the wire rope position and then stopped.

[0060] Step 4: Repeat steps 1 to 3 for each feed, and the angle of each feed is accumulated. Figure 3 The angle at position 2 is θ = A / D2 × θ0 = 11.86°. According to the geometric relationship, at this angle, the length of the empty tunnel at the overlapping area of the small-scale projection to be formed is l = 28m. The filling length of each filling process should be 28m. Figure 3 The length l is shown in the figure.

[0061] 2. Filling stage:

[0062] The filling stage is when the working face Figure 3 The 2 position in the Figure 6 The process of the 2 positions.

[0063] The steps for implementing the filling process are:

[0064] When the coal mining face is Figure 2 When the 2 position is reached, the working face process arrangement is changed, and the coal mining process is filling → coal cutting → frame moving → conveyor moving. The filling is to fill the middle area of the empty roadway with a length of l = 28m in advance with high-water materials, such as Figure 4As shown in 5 and 6, the working surface is advanced while maintaining the current tilt angle.

[0065] Entering the working face Figure 3 Position 2 in the figure changes the working face process arrangement. The coal mining process is filling → cutting coal → moving the frame → moving the conveyor. The filling is to fill the next 28m of the empty roadway with high-water material in advance. After the filling is completed, the subsequent process will be carried out. The first filling is as follows Figure 3 As shown, the second filling Figure 4 As shown, the third filling Figure 5 shown.

[0066] In this embodiment, the advancement of this stage can be completed by completing more than 4 steps, such as Figure 6 The middle 4 sections are shown as filling areas.

[0067] 3. Return to normal stage:

[0068] The return stage is when the working face changes from Figure 6 The 2 position in the Figure 8 The process of the 2 positions.

[0069] Working surface Figure 6 When it reaches position 2, the working face is gradually straightened and the normal coal mining process is restored, i.e., coal cutting → frame moving → conveyor moving.

[0070] The implementation steps for returning the working face to the correct position are:

[0071] Step 1: When the working surface is Figure 6 When it is in position 2, in a new round of cycle operation, air cutting is carried out at the end ① of the working face, and the frame is moved forward at the end ② of the working face. The frame moving distance is the rated cutting depth of the coal shearer 0.8m. When the coal shearer runs to this point, it cuts coal at the rated cutting depth.

[0072] Step 2: Connect the hydraulic supports at both ends with wire ropes and tighten the ropes. For the first coal cut of the shift, advance the remaining hydraulic supports to the wire ropes and stop. After each coal cut, the working surface will return to a small angle, maintaining a straight line. The angle of return for each cut is θ0 = arctan(0.8 / 120) = 0.38°.

[0073] Step 3: When the second coal cutting operation is carried out, the shearer is located at the end of the working face ② to advance the coal cutting and move the frame. The coal cutting depth and the frame moving distance are both the rated cutting depth of the shearer 0.8m. The hydraulic support is not moved at the end of the working face ①, and empty cutting is performed. The wire rope connecting the hydraulic supports at both ends is kept taut. When the second coal cutting operation is carried out, the remaining hydraulic supports are pushed to the wire rope and then stopped. After each shift of coal cutting, the working face will complete two small angle adjustments. The general position of the working face at this stage is as follows: Figure 7 As shown in 2.

[0074] Step 4: Repeat steps 1 to 3 each time the cut is made. The angle of return to the correct position is accumulated each time the cut is made. At this time, the coal mining face is advanced to A meters. Figure 8 The 2 position in the middle is now back to normal.

[0075] The present invention is not limited to the parallel position relationship between the old empty roadway and the working face when it is located on the roof, nor is it limited to the close-range layer relationship. It is sufficient as long as the working face is not parallel to the old empty roadway when the old empty roadway is advanced to the working face. In the case that the old empty roadway on the roof is not initially parallel to the working face, the steps of adjusting the working face tilt and returning to the right position can be omitted. The working face advancement direction is kept unchanged, and the instant filling is completed according to the requirements of the present invention during the filling stage.

[0076] Parts not described in the present invention can be implemented by referring to the existing technology.

[0077] It should be noted that any equivalent manner or obvious variation made by those skilled in the art under the guidance of this specification should fall within the scope of protection of the present invention.

Claims

1. A method for re-mining and top-controlled coal mining in thick coal seams with old empty lanes through the roof, characterized in that: The following steps are included in sequence: a. Tilt adjustment, including the following sub-steps: a1. The working face is divided into the first target position, the second target position, the third target position and the fourth target position in sequence when passing under the old empty roadway on the roof; The first target position is the position of the working face when it is 4 to 6 times the width of the old empty roadway from the top; The second target position is the working face position when the horizontal distance between the working face and the roof old empty roadway is zero or close to zero; The third target position is the position of the working face when the working face just completely passes through the roof old empty lane and there is no overlapping area between the working face and the roof old empty lane; The fourth target position and the first target position are symmetrically distributed with respect to the roof old empty lane; a2. When the coal mining face is at the first target position, gradually tilt the face to a certain angle. The specific steps are as follows: Step 1: When the working face is at the first target position and a new cycle of operation begins, the cutter is advanced at the end of the working face ① and the frame is moved forward. The coal cutting depth and frame moving distance are controlled to be the rated cutting depth of the coal shearer. The hydraulic support at the other end of the working face ② does not move, and an idle cut is performed when the coal shearer runs to the end of the working face ②. Step 2: Connect the hydraulic supports at both ends with steel wire ropes and tighten the steel wire ropes. When performing the first coal cutting operation, push the remaining hydraulic supports to the steel wire ropes and stop. After completing one coal cutting operation, the working surface will complete a small angle adjustment and keep the working surface shape straight. Step 3: When the second coal cutting operation is carried out, the shearer is located at the end of the working face ② and performs dry cutting. At the same time, the frame is advanced at the end of the working face ①. The frame is moved forward by the rated cutting depth of the shearer. When the shearer reaches this point, it is required to cut coal at the rated cutting depth. The wire ropes connecting the hydraulic supports at both ends are kept taut. When the second coal cutting operation is carried out, the remaining hydraulic supports are advanced to the wire rope position and then stopped. Step 4: Repeat steps 1 to 3 for each feed, accumulate the angle of the cutter's tilt adjustment each time, and require the coal mining face to reach the required tilt adjustment angle before reaching the second target position, until the coal mining face reaches the second target position; b. Filling The filling step is the process of the working face moving from the second target position to the third target position. When the coal mining working face advances into the filling range, the drill holes in the old empty roadway in the roof at the area where the small-scale projection overlaps are to be formed are filled with high-water materials, and the current inclination angle is maintained to continue advancing the working face. c. Return to normal The return step is the process of advancing the working surface from the third target position to the fourth target position; When the working face is at the third target position, the working face is gradually straightened and the normal coal mining process of cutting coal → moving the frame → moving the conveyor is resumed.

2. The method for top-controlled coal mining in thick coal seams with old empty lanes through roof slabs according to claim 1, characterized in that: The step c comprises the following sub-steps: c1. When the working face is at the third target position, in a new cycle of operation, the hydraulic support is not moved at the working face end ①. The shearer performs dry cutting at this point. The support is advanced at the working face end ②. The support is moved forward by the rated cutting depth of the shearer. When the shearer reaches this position, it is controlled to cut coal at the rated cutting depth. c2. Connect the hydraulic supports at both ends with steel wire ropes and tighten the steel wire ropes. When the first coal cutting operation of the shift is carried out, push the remaining hydraulic supports to the steel wire ropes and stop. After each coal cutting operation, the working surface is straightened at a small angle and the working surface shape is kept straight. c3. During the second coal cutting operation of the shift, the shearer is located at the end of the working face at position ② and advances the coal cutting and moves the frame. The coal cutting depth and frame moving distance are both the rated cutting depth of the shearer. The hydraulic support at the end of the working face at position ① is not moved. When the shearer reaches this position, it performs a dry cut. The wire rope connecting the hydraulic supports at both ends is kept taut. When the second coal cutting operation is carried out, the remaining hydraulic support is advanced to the wire rope and then stopped. c4. Repeat operations c1 to c3 each time the tool is fed, accumulate the angle of the inclination adjustment each time, and control the coal mining working face to reach the required inclination adjustment angle before reaching the second target position, until the coal mining working face reaches the fourth target position.

3. A method for top-controlled coal mining in thick coal seams with old empty lanes through roof slabs according to claim 1 or 2, characterized in that: The high-water material includes material A and material B, wherein material A is mainly made of sulphoaluminate cement clinker as a base material, mixed with corrosion inhibitor and coagulant, and material B includes lime, gypsum, suspending agent and composite rapid setting and early strength agent.

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