Freezing water control method for stope face

Abstract

The invention provides a stope face freezing water control method, and relates to the technical field of coal mine water control. According to the stope face freezing water prevention and control method, a hole is drilled in a water-bearing layer at the construction position (roadway or ground) above an overlying rock layer, pipelines are connected section by section and arranged in the hole, plugging particles are injected into the pipelines, liquid nitrogen is injected into the pipelines, the pipelines are pressurized, and the liquid nitrogen drives the plugging particles to be injected into the water-bearing layer; the plugging particles are shrunk under cold and enter cracks of the aquifer, and meanwhile, water in the aquifer is frozen by the liquid nitrogen; in this way, water in the aquifer is frozen into ice slag, and the source of water seepage and water burst of the working face is cut off. Along with the rising of the temperature of the aquifer, the plugging particles expand to the original boundary dimension, and the plugging particles plug the cracks of the aquifer, so that the water seepage and water gushing transmission path of the working face is cut off, the plugging time of the water seepage and water gushing of the working face is prolonged, and normal proceeding of working face stoping operation is ensured.

Description

Technical Field

[0001] This invention relates to the field of coal mine water control technology, specifically to a method for controlling water through freezing in longwall mining faces. Background Technology

[0002] As coal mining extends deeper, the geological environment of the mining area becomes more complex. When there is a confined aquifer overlying the coal seam, as the working face advances and the aquifer fissures develop and expand, water from the aquifer seeps into or surges into the working face and roadways. This severely affects the efficiency of the working face, increases safety hazards, and easily corrodes the mining equipment, leading to high maintenance costs. Therefore, effective measures are needed to control water seepage and inrush at the working face. Summary of the Invention

[0003] This invention provides a method for freezing and preventing water in longwall mining faces, so as to achieve freezing and sealing of the confined aquifer overlying longwall mining face.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preventing water freezing in longwall mining faces, which utilizes a drilling rig, a liquid nitrogen injection device, and a plugging particle injection device;

[0006] The method includes the following steps:

[0007] Step 1: Set up the construction position above the overburden strata on the longwall face;

[0008] Step 2: Drill several boreholes downwards at the construction location using a drilling rig. The boreholes are located above and in front of the mining face in the mining direction, extending into the aquifer.

[0009] Step 3: Connect the pipe sections one by one and lay them inside the borehole;

[0010] Step 4: Inject sealing particles into the pipeline using the sealing particle injection device;

[0011] Step 5: Inject liquid nitrogen into the pipeline through the liquid nitrogen injection device and pressurize the pipeline. The liquid nitrogen carries the sealing particles into the aquifer. The sealing particles shrink due to the cold and enter the fissures of the aquifer. At the same time, the liquid nitrogen freezes the water in the aquifer and then seals the end of the pipeline.

[0012] Step 6: After a set time, as the aquifer temperature rises, the sealing particles expand to their original size, sealing the cracks in the aquifer.

[0013] Furthermore, the liquid nitrogen injection device includes a liquid nitrogen tank, a booster pump, a liquid nitrogen supply pipeline, a liquid nitrogen delivery pipeline, and a first valve;

[0014] The liquid nitrogen tank stores liquid nitrogen. The inlet of the booster pump is connected to the liquid nitrogen tank via a liquid nitrogen supply pipeline. The outlet of the booster pump is connected to a liquid nitrogen delivery pipeline. The liquid nitrogen delivery pipeline is used to connect to the last section of the pipeline. A first valve is installed on the liquid nitrogen delivery pipeline.

[0015] Furthermore, the plugging particle injection device includes a plugging particle tank, a plugging particle delivery pipeline, and a second valve;

[0016] The sealing particle tank stores sealing particles. One end of the sealing particle tank is connected to the sealing particle delivery pipeline, and the other end of the sealing particle delivery pipeline is connected to the liquid nitrogen delivery pipeline and is located downstream of the first valve. A second valve is installed on the sealing particle delivery pipeline.

[0017] Furthermore, it also includes a tee and an injection hose. The end of the liquid nitrogen delivery pipeline is connected to the first end of the tee, the other end of the plugging particle delivery pipeline is connected to the second end of the tee, and the third end of the tee is connected to one end of the injection hose. The injection hose is made of soft material, and the other end of the injection hose is used to connect to the last section of the pipeline.

[0018] Furthermore, it also includes a transport trolley, a liquid nitrogen injection device, and a sealing particle injection device mounted on the transport trolley.

[0019] Furthermore, the sealing particles are made of soft material, and the sealing particles expand and contract with temperature changes, and the density of the sealing particles is greater than or equal to the density of water.

[0020] Furthermore, the sealing particles have a hollow structure inside, which is filled with air.

[0021] Furthermore, the soft material is configured as modified polyethylene terephthalate.

[0022] Furthermore, in step 2, the boreholes located in the aquifer are arranged at equal intervals along the strike and dip of the working face.

[0023] Furthermore, in step 3, at least one section of the pipe extending into the aquifer is configured as a perforated pipe, and the circumferential sidewall of the perforated pipe is configured as a hollow structure.

[0024] The beneficial technical effects of this invention are:

[0025] The present invention relates to a method for preventing water seepage and inrush at the working face by drilling boreholes into the aquifer at the construction location (roadway or surface) above the overlying strata. Pipes are connected section by section and laid within the boreholes. A sealing particle injection device injects sealing particles into the pipes, and a liquid nitrogen injection device injects liquid nitrogen into the pipes and pressurizes them. The liquid nitrogen carries the sealing particles into the aquifer. The sealing particles shrink upon cooling and penetrate into the fissures of the aquifer. Simultaneously, the liquid nitrogen freezes the water in the aquifer. This freezes the water in the aquifer into ice slag, cutting off the source of seepage and inrush at the working face. During the working face advance, this method reduces or even eliminates seepage and inrush at the working face and in the roadways. The simultaneous freezing of water by liquid nitrogen and the shrinking of the sealing particles allow them to penetrate more easily into the fissures of the aquifer. As the aquifer temperature rises, the sealing particles expand to their original size, sealing the fissures in the aquifer and cutting off the transmission path of seepage and inrush at the working face. This extends the sealing time for seepage and inrush at the working face, ensuring the normal progress of mining operations. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of the method for preventing water freezing in the longwall mining face according to an embodiment of the present invention;

[0027] Figure 2 This invention provides an embodiment of the construction layout for freezing and water control in the longwall mining face. Figure 1 ;

[0028] Figure 3 This invention provides an embodiment of the construction layout for freezing and water control in the longwall mining face. Figure 2 ;

[0029] Figure 4 This is a schematic diagram of the liquid nitrogen injection device and the sealing particle injection device according to an embodiment of the present invention;

[0030] Figure 5 This is a partial structural diagram of the pipeline according to an embodiment of the present invention;

[0031] Figure 6 This is a cross-sectional view of the sealing particles according to an embodiment of the present invention;

[0032] In the picture,

[0033] 1. Drilling rig; 2. Liquid nitrogen injection device; 20. Transport trolley; 201. Support leg; 202. Roller; 21. Liquid nitrogen tank; 22. Booster pump; 23. Liquid nitrogen supply pipeline; 24. Liquid nitrogen delivery pipeline; 25. First valve; 3. Sealing particle injection device; 31. Sealing particle tank; 32. Sealing particle delivery pipeline; 33. Second valve; 34. T-junction; 35. Injection hose; 4. Working face; 5. Overlying strata; 51. Aquifer; 6. Tunnel; 7. Borehole; 81. Straight pipe; 82. Perforated pipe; 9. Sealing particles; 91. Air. Detailed Implementation

[0034] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Certain embodiments of the invention will be described more fully below with reference to the accompanying drawings, and some, but not all, of these embodiments will be shown. In fact, various embodiments of the invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable the invention to meet applicable legal requirements.

[0035] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] This embodiment is based on the actual situation of a coal mine and refers to... Figures 1 to 6 As shown, a method for preventing water freezing in a longwall mining face is provided, which utilizes a drilling rig 1, a liquid nitrogen injection device 2, and a plugging particle injection device 3.

[0037] The method includes the following steps:

[0038] Step 1: Establish a construction location above the overlying strata 5 of the longwall face 4. The construction location can be a roadway or the surface. For aquifer control above each coal seam, the construction location is the surface; for aquifer control between upper and lower coal seams, the construction location is at least one roadway 6 left at the level of the upper coal seam.

[0039] Step 2: Drilling rig 1 downwards in roadway 6 to form several boreholes 7. The boreholes 7 are located above and in front of the mining face 4 in the mining direction, extending into the aquifer 51. The portion of the boreholes 7 located in the aquifer 51 is arranged at equal intervals along the strike and dip of the working face 4, so as to uniformly inject liquid nitrogen and sealing particles into the aquifer 51 in the subsequent process.

[0040] Step 3: Connect the pipe sections one by one and lay them in the borehole 7; wherein the pipe includes a straight pipe 81 and a perforated pipe 82, and the circumferential sidewall of the perforated pipe 82 is set with a hollow structure. The first few sections of the pipe are perforated pipes 82, and the other sections are straight pipes 81. Several perforated pipe sections 82 are connected and connected to each straight pipe section 81, so that at least one section of the pipe extending into the aquifer 51 is set as a perforated pipe 82.

[0041] Step 4: Inject the sealing particles 9 into the pipeline using the sealing particle injection device 3.

[0042] Step 5: Inject liquid nitrogen into the pipeline through the liquid nitrogen injection device 2 and pressurize the pipeline. The liquid nitrogen carries the sealing particles 9 into the aquifer 51. The sealing particles 9 are cooled and contracted, and enter the cracks in the aquifer 51. At the same time, the liquid nitrogen freezes the water in the aquifer 51, and then seals the end of the pipeline.

[0043] Step 6: After a set time, as the temperature of the aquifer 51 rises, the sealing particles 9 expand to their original size and seal the cracks in the aquifer 51.

[0044] The transport trolley 20 is equipped with a liquid nitrogen injection device 2 and a sealing particle injection device 3. A track is laid within the roadway 6, allowing the transport trolley 20 to travel along it, facilitating the convenient movement of the liquid nitrogen injection device and the sealing particle injection device to the construction position for liquid nitrogen and sealing particle injection operations. The transport trolley 20 is equipped with support legs 201. When the transport trolley 20 moves to the construction position, the support legs 201 are raised, causing the rollers 202 of the transport trolley 20 to disengage from the track, thus providing stable support for the transport trolley 20 and its liquid nitrogen injection device 2 and sealing particle injection device 3.

[0045] The liquid nitrogen injection device 2 includes a liquid nitrogen tank 21, a booster pump 22, a liquid nitrogen supply pipeline 23, a liquid nitrogen delivery pipeline 24, and a first valve 25. The liquid nitrogen tank 21 stores liquid nitrogen. The inlet of the booster pump 22 is connected to the liquid nitrogen tank 21 via the liquid nitrogen supply pipeline 23, and the outlet of the booster pump 22 is connected to the liquid nitrogen delivery pipeline 24. The liquid nitrogen delivery pipeline 24 is used to connect to the last section of the pipeline, and the first valve 25 is installed on the liquid nitrogen delivery pipeline 24.

[0046] The first valve 25 is opened, the second valve 33 is closed, and the booster pump 22 is started. The booster pump 22 extracts liquid nitrogen from the liquid nitrogen tank 21 and pressurizes and delivers it to the liquid nitrogen delivery pipeline 24 and other pipelines.

[0047] The plugging particle injection device 3 includes a plugging particle tank 31, a plugging particle conveying pipeline 32, and a second valve 33.

[0048] The sealing particle tank 31 stores sealing particles 9. The sealing particle tank 31 is connected to one end of the sealing particle conveying pipeline 32. The other end of the sealing particle conveying pipeline 32 is connected to the liquid nitrogen conveying pipeline 24 and is located downstream of the first valve 25. A second valve 33 is installed on the sealing particle conveying pipeline 32.

[0049] The second valve 33 is opened and the first valve 25 is closed, allowing the sealing particles 9 in the sealing particle tank 31 to enter the pipeline along the sealing particle delivery pipeline 32.

[0050] The liquid nitrogen delivery pipeline 24 is connected to the first end of the tee 34 at its end, the other end of the plugging particle delivery pipeline 32 is connected to the second end of the tee 34, and the third end of the tee 34 is connected to one end of the injection hose 35, which is made of soft material. The other end of the injection hose 35 is used to connect to the last section of the pipeline.

[0051] In this way, the liquid nitrogen delivery pipeline 24 and the sealing particle delivery pipeline 32 are connected, and the injection hose 35 can be bent and deformed to facilitate connection with the last section of the pipeline.

[0052] The sealing particles 9 are made of a soft material. Due to thermal expansion and contraction, the density of the sealing particles 9 (including the internal air 91) is slightly greater than or equal to the density of water. Specifically, the soft material is modified polyethylene terephthalate with a density of approximately 1.368 g / cm³. 3 The sealing particles 9 have a hollow internal structure filled with air 91. This allows for significant volume changes due to thermal expansion and contraction, resulting in an overall density slightly greater than or equal to that of water. This density ensures that after entering the aquifer 51, the sealing particles 9 can remain suspended in the water under the impact of liquid nitrogen and can easily penetrate the fissures within the aquifer 51.

[0053] The present invention has been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the method for preventing water seepage in the working face of the present invention. The method for preventing water seepage in the working face of the present invention involves drilling a borehole 7 into the aquifer 51 from the construction location (roadway 6 or ground) above the overlying stratum 5, connecting and laying pipes section by section within the borehole 7, injecting sealing particles 9 into the pipes through a sealing particle injection device 3, and injecting liquid nitrogen into the pipes and pressurizing the pipes through a liquid nitrogen injection device 2. The liquid nitrogen carries the sealing particles 9 into the aquifer 51. The sealing particles 9 contract upon cooling and enter the fissures of the aquifer 51. Simultaneously, the liquid nitrogen freezes the water in the aquifer 51. Thus, the water in the aquifer 51 is frozen into ice slag, cutting off the source of seepage and water inrush at the working face 4. During the advancement of the working face 4, this reduces or even eliminates seepage and water inrush in the working face 4 and roadways. While liquid nitrogen freezes the water, the sealing particles 9 shrink due to the cold, allowing them to penetrate more easily into the fissures of the aquifer 51. As the temperature of the aquifer 51 rises, the sealing particles 9 expand to their original size, sealing the fissures in the aquifer 51 and thus cutting off the transmission path of seepage and inrush water at the working face 4. This extends the sealing time for seepage and inrush water at the working face 4, ensuring the normal progress of the mining operation at the working face 4.

[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preventing waterlogging in a longwall mining face, characterized in that, Applications include drilling rigs, liquid nitrogen injection devices, and sealing particle injection devices; The method includes the following steps: Step 1: Set up the construction position above the overburden strata on the longwall face; Step 2: Drill several boreholes downwards at the construction location using a drilling rig. The boreholes are located above and in front of the mining face in the mining direction, extending into the aquifer. Step 3: Connect the pipe sections one by one and lay them inside the borehole; Step 4: Inject sealing particles into the pipeline using the sealing particle injection device; Step 5: Inject liquid nitrogen into the pipeline through the liquid nitrogen injection device and pressurize the pipeline. The liquid nitrogen carries the sealing particles into the aquifer. The sealing particles shrink due to the cold and enter the fissures of the aquifer. At the same time, the liquid nitrogen freezes the water in the aquifer and then seals the end of the pipeline. Step 6: After a set time, as the aquifer temperature rises, the sealing particles expand to their original size, sealing the cracks in the aquifer.

2. The method for preventing freezing water in a longwall mining face according to claim 1, characterized in that, The liquid nitrogen injection device includes a liquid nitrogen tank, a booster pump, a liquid nitrogen supply pipeline, a liquid nitrogen delivery pipeline, and a first valve; The liquid nitrogen tank stores liquid nitrogen. The inlet of the booster pump is connected to the liquid nitrogen tank via a liquid nitrogen supply pipeline. The outlet of the booster pump is connected to a liquid nitrogen delivery pipeline. The liquid nitrogen delivery pipeline is used to connect to the last section of the pipeline. A first valve is installed on the liquid nitrogen delivery pipeline.

3. The method for preventing freezing water in a longwall mining face according to claim 2, characterized in that, The plugging particle injection device includes a plugging particle tank, a plugging particle delivery pipeline, and a second valve; The sealing particle tank stores sealing particles. One end of the sealing particle tank is connected to the sealing particle delivery pipeline, and the other end of the sealing particle delivery pipeline is connected to the liquid nitrogen delivery pipeline and is located downstream of the first valve. A second valve is installed on the sealing particle delivery pipeline.

4. A method for preventing freezing water in a longwall mining face according to claim 3, characterized in that, It also includes a tee and an injection hose. The end of the liquid nitrogen delivery pipeline is connected to the first end of the tee, the other end of the plugging particle delivery pipeline is connected to the second end of the tee, and the third end of the tee is connected to one end of the injection hose. The injection hose is made of soft material, and the other end of the injection hose is used to connect to the last section of the pipeline.

5. A method for preventing freezing water in a longwall mining face according to claim 3, characterized in that, It also includes a transport trolley, a liquid nitrogen injection device, and a sealing particle injection device mounted on the transport trolley.

6. A method for preventing freezing water in a longwall mining face according to any one of claims 1 to 5, characterized in that, The sealing particles are made of soft material, and they expand and contract with temperature changes. The density of the sealing particles is greater than or equal to that of water.

7. A method for preventing freezing water in a longwall mining face according to claim 6, characterized in that, The sealing particles have a hollow structure inside, which is filled with air.

8. A method for preventing freezing water in a longwall mining face according to claim 6, characterized in that, The soft material is a modified polyethylene terephthalate.

9. A method for preventing freezing water in a longwall mining face according to claim 1, characterized in that, In step 2, the boreholes located in the aquifer are arranged at equal intervals along the strike and dip of the working face.

10. A method for preventing freezing water in a longwall mining face according to claim 1, characterized in that, In step 3, at least one section of the pipe extending into the aquifer is configured as a perforated pipe, and the circumferential sidewalls of the perforated pipe are configured as a hollow structure.

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