A fully mechanized caving and backfilling mining method for high-gas thick coal seams

Abstract

This invention discloses a fully mechanized longwall mining method for high-gas, thick coal seams, specifically a method for backfilling. It utilizes a gas extraction and backfilling roadway located within the overlying strata to simultaneously perform gas extraction and backfilling. This achieves multi-purpose use of a single borehole, allowing gas extraction through drilling at the working face and backfilling through boreholes behind the working face. This parallel operation of backfilling and mining improves mining efficiency and solves the problem of backfilling limiting mining efficiency. First, gas is extracted through boreholes, reducing the gas concentration at the working face. Then, backfilling is performed from top to bottom through the boreholes, improving backfilling efficiency and addressing the issue of insufficient height in traditional backfilling supports. Simultaneously, the backfill slurry, after being injected into the goaf, forms a backfill body, creating an integral support structure that connects to the roof, exhibiting strong load-bearing capacity and controlling surface subsidence, thus solving the problem of large-scale subsidence caused by fully mechanized longwall mining.

Description

Technical Field

[0001] This invention relates to the field of coal seam mining, and in particular to a fully mechanized caving and backfilling mining method for high-gas, thick coal seams. Background Technology

[0002] Fully mechanized longwall mining boasts high output, high efficiency, low cost, small tunnel excavation volume, and strong adaptability to geological conditions. However, it also faces disadvantages such as high coal loss, flammability, large amounts of coal dust, and easy gas accumulation. Backfilling mining can effectively solve the problem of coal seam blockage, reduce environmental pollution caused by surface gangue accumulation and fly ash, control surface subsidence, and protect surface buildings. However, current backfilling mining methods suffer from low backfilling efficiency, the inability to completely parallel backfilling and mining operations, and imperfect backfill isolation technology.

[0003] Many domestic patents currently address parallel mining and filling operations by altering the support structure. However, this inevitably increases the roof control distance, imposes stringent requirements on working resistance, lacks adaptability to special geological conditions, and the filling height is often limited by the support filling template, hindering production capacity release. Some patents optimize the layout of underground roadways; however, by excavating auxiliary roadways at the same level for filling, parallel mining and filling operations cannot be achieved due to mining activity and process limitations. Filling restricts mining efficiency, hinders production capacity release, and results in low filling rates, making it difficult to suppress roof subsidence and surface collapse. Furthermore, the filling materials are often loose, not connected to the roof, difficult to compact, and have poor load-bearing capacity. Summary of the Invention

[0004] To address the above technical problems, this invention provides a fully mechanized caving and backfilling mining method for high-gas thick coal seams, which enables parallel operations of backfilling and mining, and solves the problems of backfilling restricting mining efficiency and large-scale subsidence caused by fully mechanized caving mining.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a fully mechanized caving and backfilling mining method for high-gas thick coal seams, comprising the following steps:

[0007] Step 1: Arrange the transport roadways and track roadways of the mining area along the strike direction of the coal seam;

[0008] Step 2: Arrange a gas drainage and backfill roadway parallel to the strike direction of the coal seam in the overlying strata above the working face.

[0009] Step 3: Arrange an inclined tunnel whose upper end is connected to the gas extraction and filling tunnel and whose lower end is connected to the transport tunnel or the track tunnel. The inclined tunnel is used for personnel walking and material transportation.

[0010] Step 4: Transport the gas extraction and backfilling equipment through the inclined tunnel to the rear of the gas extraction and backfilling tunnel;

[0011] Step 5: At a certain distance from the working face, drill holes in the overlying strata to form at least one group of boreholes. Each group of boreholes includes multiple boreholes in different directions, and each borehole penetrates the bottom of the overlying strata. The multiple boreholes in each group of boreholes are arranged on the same plane, and the plane where the multiple boreholes in each group of boreholes are located is parallel to the working face. Coal seam mining is carried out, and gas is extracted through the borehole groups and the extraction and filling equipment. As a goaf is formed behind the coal seam mining, the extraction and filling equipment is used to inject filling slurry into the goaf through the borehole groups to form a filling body.

[0012] Step Six: As the working face advances, repeat the work in Step Five until the mining of the coal seam is completed.

[0013] Preferably, in step two, a gas extraction and filling roadway parallel to the coal seam strike direction is arranged at the center of the overlying strata above the working face.

[0014] Preferably, in step three, there are two inclined lanes. The upper and lower ends of one inclined lane are connected to the gas extraction and filling lane and the transport lane, respectively, and the upper and lower ends of the other inclined lane are connected to the gas extraction and filling lane and the track lane, respectively.

[0015] Preferably, in step three, the two inclined roadways are arranged on the same plane, and the plane in which the two inclined roadways are located is perpendicular to the direction of the coal seam strike.

[0016] Preferably, in step four, the gas extraction and filling equipment includes a gas extraction pump, a gas transport pipe, a slurry transport pipe, and multiple gas extraction and filling pipes. The gas extraction pump, one end of the gas transport pipe, one end of the slurry transport pipe, and multiple gas extraction and filling pipes are transported through the inclined roadway to the rear of the gas extraction and filling roadway. The other end of the slurry transport pipe is located outside the mining area. One end of the gas transport pipe is connected to the gas extraction pump, and the other end of the gas transport pipe is located outside the mining area.

[0017] Preferably, in step five, a gas extraction and filling pipe is inserted into each of the boreholes. When gas needs to be extracted, multiple gas extraction and filling pipes are connected to the gas extraction pump, and the gas extraction pump is turned on to perform extraction. After extraction is completed, the multiple gas extraction and filling pipes are separated from the gas extraction pump.

[0018] Preferably, in step five, when grouting is required, multiple extraction and filling pipes are connected to the slurry transport pipe, and the filling slurry is injected into the goaf through the slurry transport pipe and the extraction and filling pipe.

[0019] Preferably, in step five, after gas extraction and before grouting, multiple extraction and filling pipes are connected to the slurry transport pipe, and water is injected into the goaf through the slurry transport pipe and the extraction and filling pipe.

[0020] Preferably, in step five, at a distance of 15m to 20m in front of the working face, holes are drilled into the overlying rock strata to form at least one group of holes.

[0021] Preferably, in step five, the drilling group includes three drilling holes, with the middle drilling hole being vertically arranged and the two drilling holes on both sides being inclined, and the diameter of the drilling holes being 150mm.

[0022] The present invention achieves the following technical effects compared to the prior art:

[0023] This invention relates to a fully mechanized longwall mining method for high-gas, thick coal seams. It employs a gas extraction and filling roadway located within the overlying strata to simultaneously perform gas extraction and filling. This achieves multi-purpose use of a single borehole; gas is extracted through boreholes drilled at the working face, and filling is carried out behind the working face. This parallel operation of filling and mining improves mining efficiency and solves the problem of filling restricting mining efficiency, thus facilitating further release of fully mechanized longwall mining capacity. First, gas is extracted through boreholes, reducing the gas concentration at the working face. Then, grouting is performed from top to bottom through the boreholes, improving filling efficiency and solving the problem of insufficient height in traditional filling supports. Simultaneously, the filling grout, after being injected into the goaf, forms a filling body, creating an integral support structure that can connect to the roof, exhibiting strong load-bearing capacity and controlling surface subsidence, thus solving the problem of large-scale subsidence caused by fully mechanized longwall mining. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a front view of the roadway layout for the fully mechanized caving and backfilling mining method for high-gas thick coal seams provided by the present invention.

[0026] Figure 2 This is a top view of the roadway layout for the fully mechanized caving and backfilling mining method for high-gas thick coal seams provided by the present invention.

[0027] Explanation of reference numerals in the attached diagram: 1. Coal seam; 2. Overlying strata; 3. Transport roadway; 4. Track roadway; 5. Gas drainage and backfilling roadway; 6. Inclined roadway; 7. Borehole; 8. Backfilling body. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a fully mechanized caving and backfilling mining method for high-gas thick coal seams, which realizes parallel operation of backfilling and mining, and solves the problems of backfilling restricting mining efficiency and large-scale subsidence caused by fully mechanized caving mining.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figures 1-2 As shown, this embodiment provides a fully mechanized caving and backfilling mining method for high-gas thick coal seams 1, including the following steps:

[0032] Step 1: Arrange the transport roadway 3 and track roadway 4 in the mining area along the strike direction of coal seam 1; specifically, transport roadway 3 can also be used for intake air, and track roadway 4 can also be used for return air.

[0033] Step 2: Arrange a gas extraction and filling roadway 5 in the overlying strata 2 above the working face, parallel to the strike direction of coal seam 1.

[0034] Step 3: Arrange an inclined roadway 6, whose upper end is connected to the gas extraction and filling roadway 5 and whose lower end is connected to the transport roadway 3 or the track roadway 4. The inclined roadway 6 is used for personnel walking and material transportation.

[0035] Step 4: Transport the gas extraction and backfilling equipment through inclined roadway 6 to the rear of gas extraction and backfilling roadway 5.

[0036] Step 5: At a certain distance from the working face, drill holes in the overlying rock stratum 2 to form at least one borehole group. The borehole group includes multiple boreholes 7 in different directions. Each borehole 7 penetrates the bottom of the overlying rock stratum 2. The multiple boreholes 7 in each borehole group are set on the same plane. The plane where the multiple boreholes 7 in each borehole group are located is parallel to the working face. Coal seam 1 is mined, and gas is extracted through the borehole group and extraction and filling equipment. As the coal seam 1 is mined, a goaf is formed behind it. The extraction and filling equipment is used to inject filling slurry into the goaf through the borehole group to form a filling body 8.

[0037] Step Six: As the working face advances, repeat the work in Step Five until the mining of coal seam 1 is completed. Specifically, the borehole sets are not drilled all at once, but rather drilled in advance as the working face advances.

[0038] In this embodiment, five gas extraction and filling roadways are set in the overlying stratum 2 for gas extraction and filling. This realizes the multi-purpose use of a single borehole. That is, gas is extracted by drilling a borehole in the working face ahead, and filling is carried out in the borehole behind the working face. This enables parallel operation of filling and mining, improves mining efficiency, solves the problem of filling restricting mining efficiency, and is conducive to the further release of fully mechanized caving mining capacity.

[0039] Specifically, gas is first extracted through borehole 7, reducing the gas concentration at the working face and effectively preventing gas accidents caused by high-intensity mining. Then, grouting is injected from top to bottom through borehole 7, improving filling efficiency and solving the problem of insufficient height in traditional filling supports. Simultaneously, the filling grout, after being injected into the goaf, forms a filling body 8, creating an integral support structure that connects to the roof, exhibiting strong load-bearing capacity. This controls surface subsidence, solving the problem of large-scale subsidence caused by fully mechanized longwall mining and promoting green coal mining. Therefore, this method can effectively solve problems such as excessive roof pressure, spontaneous combustion underground, and excessively high gas and dust concentrations. Under special geological conditions and on an economically feasible basis, it has promotional value.

[0040] In this embodiment, after adopting the goaf filling technology, the filling body 8 will maintain the stability of the roof structure together with the coal wall, and part of the roof pressure will be transferred to the filling body 8, thereby mitigating the damage to the coal wall. By grouting and filling the goaf, the air leakage in the goaf is sealed, which reduces the spontaneous combustion of coal in the goaf to a certain extent. That is, because the filling body 8 separates the working face, the spontaneous combustion of residual coal in the goaf is reduced.

[0041] Specifically, in step two, a gas drainage and backfilling roadway 5, parallel to the strike direction of coal seam 1, is arranged at the center of the overlying stratum 2 above the working face. In this embodiment, the gas drainage and backfilling roadway 5 is located in the stable stratum of the overlying stratum 2.

[0042] In this embodiment, the gas drainage and backfilling roadway 5 is set within the overlying stratum 2, which is less affected by mining. This ensures that the gas drainage and backfilling roadway 5 still has sufficient strength and stability during top coal recovery. Even if affected by mining, it can be maintained in normal use through simple support, thus ensuring the stability of the gas drainage and backfilling roadway 5.

[0043] At the same time, it ensures that the mining and backfilling operations are not in the same layer, so that they do not interfere with each other. This allows for parallel operations of backfilling and mining, improving the mining efficiency of the backfilling face and solving the problem of backfilling restricting mining efficiency.

[0044] In step three, inclined roadways 6 are arranged near the coal pillars left at the boundary of the mining area. Specifically, two inclined roadways 6 are configured. One inclined roadway 6 is connected at its upper and lower ends to the gas drainage and filling roadway 5 and the transport roadway 3, respectively. The other inclined roadway 6 is connected at its upper and lower ends to the gas drainage and filling roadway 5 and the track roadway 4, respectively. By configuring two inclined roadways 6, it is easier for operators to carry equipment and materials into the gas drainage and filling roadway 5, which helps to improve the working environment inside the gas drainage and filling roadway 5.

[0045] In this specific embodiment, the two inclined roadways 6 are arranged on the same plane, and the plane on which the two inclined roadways 6 are located is perpendicular to the direction of the coal seam 1.

[0046] In step four, the gas extraction and filling equipment includes a gas extraction pump, a gas transport pipe, a slurry transport pipe, and multiple gas extraction and filling pipes. The gas extraction pump, one end of the gas transport pipe, one end of the slurry transport pipe, and multiple gas extraction and filling pipes are transported through the inclined roadway 6 to the rear of the gas extraction and filling roadway 5. The other end of the slurry transport pipe is located outside the mining area. The slurry transport pipe is used to transport the prepared filling slurry to the gas extraction and filling roadway 5. One end of the gas transport pipe is connected to the gas extraction pump, and the other end of the gas transport pipe is located outside the mining area. The gas transport pipe is used to transport the extracted gas to the outside.

[0047] Specifically, the gas transported from the other end of the gas transport pipe can be stored and utilized at the mine's own gas storage station, or it can be directly connected to the provincial oil and gas pipeline and go through the provincial energy system.

[0048] In step five, a gas extraction and filling pipe is inserted into each borehole 7. When gas needs to be extracted, multiple gas extraction and filling pipes are connected to the extraction pump, and the extraction pump is turned on to extract the gas. After the extraction is completed, the multiple gas extraction and filling pipes are separated from the extraction pump.

[0049] In step five, when grouting is required, multiple extraction and filling pipes are connected to the slurry transport pipe, and filling slurry is injected into the goaf through the slurry transport pipe and the extraction and filling pipe.

[0050] In this specific embodiment, the filling slurry is a high-concentration cemented filling slurry.

[0051] In step five, after gas extraction and before grouting, multiple extraction and filling pipes are connected to slurry transport pipes. Water is then injected into the goaf through the slurry transport pipes and the extraction and filling pipes, essentially spraying water near the working face to reduce dust concentration. After dust suppression is complete, filling slurry is injected into the goaf through the slurry transport pipes and the extraction and filling pipes.

[0052] The distance for drilling ahead of the working face is determined based on the working conditions. This range is determined after taking into account factors such as gas emission rate, coalbed methane content, geological conditions, and the mine ventilation system. Too small a lead distance may fail to effectively control gas concentration, increasing the risk of gas explosion; while too large a lead distance may lead to poor gas drainage.

[0053] In this specific embodiment, at a distance of 15m to 20m in front of the working face, at least one borehole group is formed by drilling holes in the overlying rock layer 2, which can effectively control the gas concentration and ensure the gas extraction effect.

[0054] In this embodiment, the drilling group includes multiple boreholes 7 arranged in different directions and on the same plane, ensuring that the direction of each borehole 7 is evenly distributed in its plane, so that the filling body 8 can completely fill the entire goaf area.

[0055] In step five, the number of boreholes 7 is arranged reasonably according to the length of the working face. The boreholes 7 should be able to ensure the extraction and filling of the working face. In this embodiment, the borehole group includes three boreholes 7. The borehole 7 in the middle is set vertically, and the two boreholes 7 on both sides are set at an angle. The diameter of the boreholes 7 is 150mm. It should be noted that the number and diameter of the boreholes 7 can be determined according to the working conditions.

[0056] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A fully mechanized caving and backfilling mining method for high-gas thick coal seams, characterized in that, Includes the following steps: Step 1: Arrange the transport roadways and track roadways of the mining area along the strike direction of the coal seam; Step 2: Arrange a gas drainage and backfill roadway parallel to the strike direction of the coal seam in the overlying strata above the working face. Step 3: Arrange an inclined tunnel whose upper end is connected to the gas extraction and filling tunnel and whose lower end is connected to the transport tunnel or the track tunnel. The inclined tunnel is used for personnel walking and material transportation. Step 4: Transport the gas extraction and backfilling equipment through the inclined tunnel to the rear of the gas extraction and backfilling tunnel; In step four, the gas extraction and filling equipment includes a gas extraction pump, a gas transport pipe, a slurry transport pipe, and multiple gas extraction and filling pipes. The gas extraction pump, one end of the gas transport pipe, one end of the slurry transport pipe, and multiple gas extraction and filling pipes are transported through the inclined roadway to the rear of the gas extraction and filling roadway. The other end of the slurry transport pipe is located outside the mining area. One end of the gas transport pipe is connected to the gas extraction pump, and the other end of the gas transport pipe is located outside the mining area. Step 5: At a certain distance from the working face, drill holes in the overlying strata to form at least one group of boreholes. Each group of boreholes includes multiple boreholes in different directions, and each borehole penetrates the bottom of the overlying strata. The multiple boreholes in each group of boreholes are arranged on the same plane, and the plane where the multiple boreholes in each group of boreholes are located is parallel to the working face. Coal seam mining is carried out, and gas is extracted through the borehole groups and the extraction and filling equipment. As a goaf is formed behind the coal seam mining, the extraction and filling equipment is used to inject filling slurry into the goaf through the borehole groups to form a filling body. In step five, a gas extraction and filling pipe is inserted into each of the boreholes. When gas needs to be extracted, multiple gas extraction and filling pipes are connected to the gas extraction pump, and the gas extraction pump is turned on to extract the gas. After extraction is completed, the multiple gas extraction and filling pipes are disconnected from the gas extraction pump. When grouting is required, multiple gas extraction and filling pipes are connected to the slurry transport pipe, and the filling slurry is injected into the goaf through the slurry transport pipe and the gas extraction and filling pipes. Step Six: As the working face advances, repeat the work in Step Five until the mining of the coal seam is completed.

2. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 1, characterized in that, In step two, a gas extraction and filling roadway parallel to the coal seam strike direction is arranged at the center of the overlying strata above the working face.

3. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 1, characterized in that, In step three, two inclined tunnels are configured. The upper and lower ends of one inclined tunnel are connected to the gas extraction and filling tunnel and the transport tunnel, respectively. The upper and lower ends of the other inclined tunnel are connected to the gas extraction and filling tunnel and the track tunnel, respectively.

4. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 3, characterized in that, In step three, the two inclined roadways are arranged on the same plane, and the plane in which the two inclined roadways are located is perpendicular to the direction of the coal seam strike.

5. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 1, characterized in that, In step five, after gas extraction and before grouting, multiple extraction and filling pipes are connected to the slurry transport pipe, and water is injected into the goaf through the slurry transport pipe and the extraction and filling pipe.

6. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 1, characterized in that, In step five, at a distance of 15m to 20m in front of the working face, holes are drilled into the overlying rock strata to form at least one group of holes.

7. The fully mechanized caving and backfilling mining method for high-gas thick coal seams according to claim 1, characterized in that, In step five, the drilling group includes three drilling holes, with the middle drilling hole being vertically arranged and the two drilling holes on both sides being inclined. The diameter of each drilling hole is 150mm.

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