A coal mining method using freezing method through wind oxidation zone

Abstract

The present invention discloses a method for mining coal by freezing through a wind oxidation zone, comprising the following steps: S01: detecting a wind oxidation zone area in a coal seam; S02: drilling a plurality of freezing boreholes, insulation boreholes and pressure relief boreholes from a tunnel to the wind oxidation zone area; S03: arranging a freezing liquid supply device, a liquid supply pipe, a liquid return pipe, a liquid supply pump and a reflux pump in the tunnel, and installing a freezing pipe in each freezing borehole; S04: supplying freezing liquid to the freezing pipe by using the freezing liquid supply device to freeze the wind oxidation zone area; S05: stopping supplying freezing liquid and recovering the freezing liquid in the freezing pipe; S06: installing an insulation pipe in each insulation borehole; S07: mining the wind oxidation zone area at a coal mining working face, and recovering the insulation pipe ahead of the coal mining working face. The present invention provides a new method for mining a coal seam with a wind oxidation zone by pre-freezing the wind oxidation zone area and then mining the wind oxidation zone area.

Description

Technical Field

[0001] The invention relates to the technical field of coal mines, and in particular to a coal mining method using a freezing method through a wind oxidation zone. Background Art

[0002] Under the influence of water, atmosphere, heat and organisms, the composition and structure of rock strata and coal seams will change to form fractured and broken weathering zones and oxidation zones, collectively referred to as wind-oxidized zones. When encountering wind-oxidized zones during coal mining, insufficient initial support pressure, frame collapse, frame compression and other phenomena often occur, affecting the normal recovery of the working face. When there is an aquifer at the top, there are dangers such as water inrush and sand collapse, which increases the risk factor of coal mining. In addition, if there are faults, folds and other structures near the wind-oxidized zone, the lithological characteristics of the wind-oxidized zone are often variable, and sand, gravel, block stone, mudstone and other structures appear alternately, which undoubtedly increases the difficulty of mining. Special methods are needed to change the strength and integrity of the broken rock and soil to ensure safe production. At present, the reinforcement method for loose bodies, weakly cemented rock strata is mainly grouting reinforcement. However, the loess, clay and other properties in the wind-oxidized zone are dense, making it difficult for the slurry to spread, resulting in poor reinforcement effect. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a coal mining method that adopts a freezing method to pass through a wind-oxidized zone. It freezes the wind-oxidized zone area in advance and then mines the wind-oxidized zone area, thereby providing a new method for mining coal seams with wind-oxidized zones.

[0004] The technical solution of the present invention provides a method for coal mining through a wind oxidation zone by freezing, comprising the following steps:

[0005] S01: Use geophysical exploration and drilling to detect the wind oxidation zone in the coal seam;

[0006] S02: Drilling a plurality of freezing boreholes, heat-insulating boreholes and pressure-relieving boreholes from the tunnel to the wind-oxidized zone area;

[0007] S03: Arrange a freezing liquid supply device, a liquid supply pipe, a liquid return pipe, a liquid supply pump and a reflux pump in the tunnel;

[0008] Install a freezing pipe in each of the freezing boreholes, connect the liquid inlet of each freezing pipe to the liquid supply pipe, and connect the liquid outlet of each freezing pipe to the liquid return pipe;

[0009] S04: using the freezing liquid supply device to supply freezing liquid into the freezing pipe to freeze the wind oxidation zone area;

[0010] S05: the freezing liquid supply device stops supplying the freezing liquid and recovers the freezing liquid in the freezing pipe;

[0011] S06: installing an insulation pipe in each of the insulation boreholes, wherein liquid ammonia is stored in the insulation pipe, and one end of the insulation pipe extends into the tunnel for heat exchange;

[0012] S07: The coal mining working face mines the wind oxidation zone along the advancing direction, wherein the insulation pipes are successively recovered ahead of the coal mining working face in the tunnel.

[0013] In one of the optional technical solutions, the insulation pipe includes an insulation pipe inner pipe and an insulation pipe outer pipe sleeved on the insulation pipe inner pipe;

[0014] The pipe opening of the inner pipe of the thermal insulation pipe is provided with an inner pipe sealing cover, and liquid ammonia is stored in the inner pipe of the thermal insulation pipe;

[0015] The inner tube of the thermal insulation pipe is longer than the outer tube of the thermal insulation pipe, and one end of the inner tube of the thermal insulation pipe having the inner tube sealing cover of the thermal insulation pipe extends out of the outer tube of the thermal insulation pipe;

[0016] The outer tube of the insulation pipe is inserted into the insulation borehole, and the portion of the inner tube of the insulation pipe extending out of the outer tube of the insulation pipe extends into the tunnel;

[0017] When the insulation pipe is recovered, the outer pipe of the insulation pipe remains in the insulation borehole, and the inner pipe of the insulation pipe is pulled out from the outer pipe of the insulation pipe.

[0018] In one of the optional technical solutions, a handle is provided on the inner tube sealing cover of the thermal insulation tube for connecting a rope of a traction device.

[0019] In one of the optional technical solutions, the outer diameter of the inner tube of the insulation tube is smaller than the inner diameter of the outer tube of the insulation tube, and a plurality of annular brackets are spaced apart on the inner tube of the insulation tube. A plurality of balls are provided on the outer annular surface of the annular brackets, and the balls are in contact with the inner surface of the outer tube of the insulation tube.

[0020] In one of the optional technical solutions, after the freezing liquid in the freezing pipe is recovered, the freezing pipe is recovered in the tunnel.

[0021] In one of the optional technical solutions, the freezing pipe includes a freezing pipe inner pipe and a freezing pipe outer pipe sleeved on the freezing pipe inner pipe, and an annular flow channel is formed between the freezing pipe inner pipe and the freezing pipe outer pipe;

[0022] An annular end cover is provided between the outer tube of the freezing tube and one end of the inner tube of the freezing tube, and a liquid inlet joint is provided on the annular end cover, and the liquid inlet joint is connected to the liquid supply pipe;

[0023] A freezing pipe inner pipe sealing cover is provided at one end of the freezing pipe inner pipe, an inner pipe liquid inlet communicating with the annular flow channel is provided at the other end of the freezing pipe inner pipe, a liquid outlet joint is provided on the freezing pipe inner pipe sealing cover, and the liquid outlet joint is connected to the liquid return pipe;

[0024] When the freezing pipe is recovered, the outer pipe of the freezing pipe remains in the freezing borehole, and the inner pipe of the freezing pipe is pulled out from the outer pipe of the freezing pipe.

[0025] In one of the optional technical solutions, a connector groove is provided on the circumferential surface of the liquid outlet connector for connecting a rope of a traction device.

[0026] In one of the optional technical solutions, a plurality of support brackets are provided at intervals on the inner tube of the freezing tube, and the support brackets are located in the annular flow channel and are slidably connected to the outer tube of the freezing tube.

[0027] In one of the optional technical solutions, the step S02 also includes: drilling a plurality of temperature measuring holes from the tunnel to the wind oxidation zone area.

[0028] In one of the optional technical solutions, the freezing borehole, the heat-insulating borehole and the pressure-relieving borehole extend upwardly at an angle respectively;

[0029] The step S02 further includes: drilling a plurality of rows of freezing boreholes and a plurality of rows of insulation boreholes arranged at intervals from the tunnel to the wind oxidation zone;

[0030] Wherein, in the vertical direction and the horizontal direction, there is a row of the insulation drilled holes between every two rows of the freezing drilled holes.

[0031] The above technical solution has the following beneficial effects:

[0032] The present invention provides a coal mining method that adopts freezing to pass through a wind-oxidized zone. The freezing method is used to increase the strength and integrity of loose rock and soil, thereby avoiding problems such as bubbling during mining, water inrush and sand collapse, support collapse, and insufficient initial support force during the mining process. This provides a safe method for water conservancy projects such as mines and tunnels or underground projects to pass through broken wind-oxidized zone areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. It should be understood that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings:

[0034] Figure 1 A schematic diagram of the steps of a method for coal mining through a wind oxidation zone using a freezing method provided by an embodiment of the present invention;

[0035] Figure 2 Schematic diagram of drilling multiple freezing boreholes, insulation boreholes and pressure relief boreholes from the roadway to the wind oxidation zone area;

[0036] Figure 3 It is a schematic diagram of the arrangement of multiple freezing pipes and insulation pipes along the advancing direction of the coal mining working face;

[0037] Figure 4 It is a cross-sectional view of the freezing pipe along the axial direction;

[0038] Figure 5 It is a cross-sectional view of the freezing pipe along the supporting bracket;

[0039] Figure 6 A cross-sectional view of a thermal insulation pipe of a structure along the axial direction;

[0040] Figure 7 A cross-sectional view of an insulation pipe of another structure along the axial direction. DETAILED DESCRIPTION

[0041] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The same components are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0042] like Figure 1-3 As shown, a method for mining coal through a wind oxidation zone by freezing is provided in one embodiment of the present invention, comprising the following steps:

[0043] S01: Use geophysical exploration and drilling to detect the wind oxidation zone area 2 in the coal seam.

[0044] S02: Drill multiple freezing boreholes 3, insulation boreholes 5 and pressure relief boreholes 4 from tunnel 1 to wind oxidation zone area 2.

[0045] S03: Arrange a freezing liquid supply device 8, a liquid supply pipe 9, a liquid return pipe 10, a liquid supply pump 11 and a reflux pump 12 in the tunnel 1.

[0046] A freezing pipe 6 is installed in each freezing borehole 3 , and the liquid inlet of each freezing pipe 6 is connected to the liquid supply pipe 9 , and the liquid outlet of each freezing pipe 6 is connected to the liquid return pipe 10 .

[0047] S04: Use the freezing liquid supply device 8 to supply freezing liquid to the freezing pipe 6 to freeze the wind oxidation zone area 2.

[0048] S05: The freezing liquid supply device 8 stops supplying the freezing liquid and recovers the freezing liquid in the freezing pipe 6.

[0049] S06: Install an insulation pipe 7 in each insulation borehole 5. Liquid ammonia 75 is stored in the insulation pipe 7. One end of the insulation pipe 7 extends into the tunnel 1 for heat exchange.

[0050] S07: The coal mining face mines the wind oxidation zone area 2 along the advancing direction, wherein the insulation pipes 7 are recovered one by one in the leading coal mining face in the tunnel 1.

[0051] The coal mining method provided by the present invention freezes the entire area of ​​the wind oxidation zone in the coal seam in advance, and then utilizes the coal mining working face to mine through the frozen wind oxidation zone area 2 to achieve coal mining in the wind oxidation zone area 2.

[0052] The steps of the coal mining method are as follows:

[0053] The first step is to use drilling, geophysical exploration and other means to determine the location and volume of the wind-oxidized zone area 2 in the coal seam, including the burial depth, boundary, and relationship with the coal seam.

[0054] The second step is to arrange drilling holes according to the basic conditions of the wind oxidation zone area 2. The drilling holes are arranged in two ways: from a single-side tunnel 1 and from a double-side tunnel 1.

[0055] The boreholes include a plurality of freezing boreholes 3, a plurality of insulation boreholes 5, and a plurality of pressure relief boreholes 4. The freezing boreholes 3 are used to install freezing pipes 6, and the insulation boreholes 5 are used to install insulation pipes 7. The length of the pressure relief boreholes 4 can be roughly equal to the length of the surrounding freezing boreholes 3, or can be shorter than the length of the surrounding freezing boreholes 3. The pressure relief boreholes 4 are not filled with any objects, and provide a certain pressure relief space. When freezing is performed through the freezing pipes 6, the geology around the freezing boreholes 3 will expand, and the space of the pressure relief boreholes 4 provides pressure relief space for the geological expansion.

[0056] The third step is to arrange the freezing liquid supply device 8, the liquid supply pipe 9, the liquid return pipe 10, the liquid supply pump 11 and the reflux pump 12 in advance in the lane 1. The freezing liquid supply device 8 is used to provide and recover the freezing liquid, and the freezing liquid can be low-temperature salt water, liquid nitrogen, etc. The temperature of the freezing liquid provided by the freezing liquid supply device 8 is lower than minus 10°C.

[0057] The liquid inlet of the liquid supply pipe 9 is connected to the liquid outlet of the freezing liquid supply device 8, and the liquid supply pump 11 is arranged on the liquid supply pipe 9 to provide power for the liquid supply.

[0058] The liquid outlet of the liquid return pipe 10 is connected to the liquid return port of the freezing liquid supply device 8, and the reflux pump 12 is arranged on the liquid return pipe 10 to provide power for the liquid return.

[0059] A freezing pipe 6 is installed in each freezing borehole 3, and one end of the freezing pipe 6 extends out of the freezing borehole 3 and is located in the lane 1. A liquid inlet and a liquid outlet are provided at one end of the freezing pipe 6 located in the lane 1. Multiple freezing pipes 6 are connected in parallel between the liquid supply pipe 9 and the liquid return pipe 10, and the liquid inlet of each freezing pipe 6 is connected to the liquid supply pipe 9, and the liquid outlet of each freezing pipe 6 is connected to the liquid return pipe 10.

[0060] The freezing pipe 6 has a loop in it, and the freezing liquid enters the loop of the freezing pipe 6 from the liquid inlet of the freezing pipe 6, and then flows out from the liquid outlet of the freezing pipe 6 to exchange heat with the geology around the freezing borehole 3, thereby cooling and freezing the geology around each freezing borehole 3.

[0061] As required, a three-way valve may be provided at the junction of the liquid supply pipe 9 and each freezing pipe 6 , and the three-way valve is an electric valve to control the flow of the freezing liquid entering each freezing pipe 6 .

[0062] As required, a reverse valve is provided at the junction of the return pipe 10 and each freezing pipe 6, and the reverse valve is an electric valve to prevent the return freezing liquid from flowing back.

[0063] The fourth step is to freeze the wind oxidation zone 2 before the coal mining face advances to the wind oxidation zone 2. Specifically, the freezing liquid is supplied to the freezing pipe 6 by the freezing liquid supply device 8 to freeze the wind oxidation zone 2. The freezing time can be obtained based on experiments or experience, and whether the wind oxidation zone 2 is frozen can also be detected from the tunnels 1 on both sides.

[0064] The fifth step is to wait until the wind oxidation zone 2 is completely frozen, turn off the liquid supply pump 11, keep the reflux pump 12 open, stop supplying the freezing liquid by the freezing liquid supply device 8, and recover the freezing liquid in the freezing pipe 6 to prevent the freezing liquid from flowing out and affecting the coal mining conditions during coal mining.

[0065] In the sixth step, an insulation pipe 7 is installed in each insulation borehole 5, and one end of the insulation pipe 7 extends into the tunnel 1 for heat exchange. Liquid ammonia 75 is stored in the insulation pipe 7, which can maintain the insulation pipe 7 within a certain temperature range to keep the wind oxidation zone area 2 in a frozen state. The temperature range can be controlled by designing the volume of the insulation pipe 7 and the amount of liquid ammonia injected into the insulation pipe 7.

[0066] Under normal pressure, the boiling point of liquid ammonia 75 is about -33.5°C. The boiling point of liquid ammonia 75 can increase with the increase of pressure, so the boiling point of liquid ammonia 75 can be adjusted by setting the pressure in the insulation pipe 7. The temperature of the tunnel 1 in the freezing area is about -10°C, so the liquid ammonia 75 in the insulation pipe 7 can be vaporized and absorb heat, thereby keeping the geology around the insulation borehole 5 and the freezing borehole 3 frozen.

[0067] After the wind oxidation zone area 2 is frozen, the insulation pipe 7 is installed to avoid the expansion of the geology affecting the structure of the insulation pipe 7 when the low-temperature freezing liquid in the freezing pipe 6 is used for freezing, thereby avoiding the leakage of liquid ammonia 75.

[0068] After the wind oxidation zone area 2 is frozen, the insulation pipe 7 is installed, and the drill bit can be used to drill into the insulation borehole 5 to trim the inner wall of the borehole so as to install the insulation pipe 7 into the insulation borehole 5.

[0069] In the seventh step, the coal mining face mines the wind oxidation zone area 2 along the advancing direction. When mining the wind oxidation zone area 2, the coal mining machine can cut the empty freezing pipe 6 left, and the leading coal mining face in the tunnel 1 can recover the insulation pipe 7 one by one, which can prevent the insulation pipe 7 from being cut by the coal mining machine and causing liquid ammonia 75 to leak to the coal mining face and affect the construction, and the insulation pipe 7 can be reused.

[0070] In the present invention, the freezing pipe 6 and the insulation pipe 7 are respectively heat-conducting pipes, such as metal pipes, composite material pipes, aluminum-plastic pipes, etc.

[0071] In summary, the present invention provides a coal mining method that uses freezing to pass through a wind-oxidized zone. Through the freezing method, the strength and integrity of loose rock and soil are increased, and the problems of bubbling during mining, water inrush and sand collapse, support collapse, and insufficient initial support force are avoided. This provides a safe method for mines, tunnels and other water conservancy projects or underground projects to pass through the broken wind-oxidized zone area 2.

[0072] In one embodiment, if Figure 6 As shown, the insulation pipe 7 includes an insulation pipe inner pipe 72 and an insulation pipe outer pipe 71 sleeved on the insulation pipe inner pipe 72 .

[0073] A heat-insulating tube inner tube sealing cover 73 is provided at the tube opening of the heat-insulating tube inner tube 72 , and liquid ammonia 75 is stored in the heat-insulating tube inner tube 72 .

[0074] The insulation pipe inner tube 72 is longer than the insulation pipe outer tube 71 , and one end of the insulation pipe inner tube 72 having the insulation pipe inner tube sealing cover 73 extends out of the insulation pipe outer tube 71 .

[0075] The outer tube 71 of the insulation pipe is inserted into the insulation borehole 5 , and the portion of the inner tube 72 of the insulation pipe extending out of the outer tube 71 of the insulation pipe extends into the tunnel 1 .

[0076] When the insulation pipe 7 is recovered, the insulation pipe outer pipe 71 remains in the insulation bore 5 , and the insulation pipe inner pipe 72 is pulled out from the insulation pipe outer pipe 71 .

[0077] In order to prevent the insulation pipe 7 from being frozen in the insulation bore 5 and being difficult to pull out when the insulation pipe 7 is recovered, the insulation pipe 7 in this embodiment adopts the following design scheme:

[0078] The insulation pipe 7 includes an insulation pipe inner pipe 72 and an insulation pipe outer pipe 71. The insulation pipe inner pipe 72 is longer than the insulation pipe outer pipe 71. The insulation pipe outer pipe 71 is sleeved on the insulation pipe inner pipe 72. The bottom plate of the insulation pipe inner pipe 72 contacts the bottom plate of the insulation pipe outer pipe 71. One end of the insulation pipe inner pipe 72 extends out from the outside of the insulation pipe outer pipe 71.

[0079] Liquid ammonia 75 is stored in the insulation pipe inner tube 72, and the pipe opening of the insulation pipe inner tube 72 is provided with an insulation pipe inner tube sealing cover 73 for sealing the liquid ammonia 75 in the insulation pipe inner tube 72. One end of the insulation pipe inner tube sealing cover 73 of the insulation pipe inner tube 72 extends out of the outer insulation pipe outer tube 71. The pipe opening of the insulation pipe outer tube 71 is provided with an outer tube buckle cover 74 for fixing the insulation pipe inner tube 72 to prevent the upwardly tilted insulation pipe inner tube 72 from sliding out of the insulation pipe outer tube 71.

[0080] When installing the insulation pipe 7 , the insulation pipe outer pipe 71 is inserted into the insulation borehole 5 , and the insulation pipe inner pipe 72 extends partly out of the insulation pipe outer pipe 71 and into the tunnel 1 .

[0081] When the insulation pipe 7 is recovered, the outer pipe 71 of the insulation pipe is difficult to pull out due to freezing, so the outer pipe 71 of the insulation pipe is left in the insulation borehole 5, and the inner pipe 72 of the insulation pipe is pulled out or extracted from the outer pipe 71 of the insulation pipe, thereby realizing the recovery and reuse of the inner pipe 72 of the insulation pipe storing the liquid ammonia 75.

[0082] In one embodiment, if Figure 6 As shown, a handle 731 is provided on the insulation pipe inner pipe sealing cover 73 for connecting the rope of the traction device, so as to facilitate pulling or extracting the insulation pipe inner pipe 72 from the insulation pipe outer pipe 71. The traction device can adopt a winch mechanism with a rope.

[0083] In one embodiment, if Figure 7 As shown, the outer diameter of the inner tube 72 of the insulation tube is smaller than the inner diameter of the outer tube 71 of the insulation tube, and a plurality of annular brackets 76 are sleeved on the inner tube 72 of the insulation tube at intervals. The outer ring surface of the annular bracket 76 is provided with a plurality of balls 77, and the balls 77 are in contact with the inner surface of the outer tube 71 of the insulation tube.

[0084] In order to prevent the outer tube 71 of the insulation tube from being deformed and squeezed by the outer tube 71 of the insulation tube, and the inner tube 72 of the insulation tube from being squeezed by the outer tube 71 of the insulation tube, which may cause the inner tube 72 of the insulation tube to be damaged and cause the leakage of liquid ammonia 75, and to prevent the inner tube 72 of the insulation tube from being worn and damaged by the outer tube 71 of the insulation tube when the inner tube 72 of the insulation tube is pulled out or extracted, in this embodiment, the outer diameter of the inner tube 72 of the insulation tube is smaller than the inner diameter of the outer tube 71 of the insulation tube, and the two are supported by an annular bracket 76, and the outer ring surface of the annular bracket 76 is provided with a plurality of balls 77, and the balls 77 are in contact with the inner surface of the outer tube 71 of the insulation tube. An annular space is formed between the inner tube 72 of the insulation tube and the outer tube 71 of the insulation tube, and the inner tube 72 of the insulation tube will not be squeezed when the outer tube 71 of the insulation tube is deformed, which is conducive to maintaining the integrity of the inner tube 72 of the insulation tube. When the inner tube 72 of the insulation tube is pulled or drawn, the annular bracket 76 moves integrally with the inner tube 72 of the insulation tube, and the ball 77 rolls on the inner surface of the outer tube 71 of the insulation tube, converting the sliding friction into rolling friction, which facilitates the smooth pulling or drawing out of the inner tube 72 of the insulation tube.

[0085] In one embodiment, after the freezing liquid in the freezing pipe 6 is recovered, the freezing pipe 6 is recovered in the tunnel 1, and the freezing pipe 6 can be reused, which is beneficial to saving materials and reducing costs.

[0086] In one embodiment, if Figure 4 As shown, the freezing pipe 6 includes a freezing pipe inner pipe 62 and a freezing pipe outer pipe 61 sleeved on the freezing pipe inner pipe 62 , and an annular flow channel 66 is formed between the freezing pipe inner pipe 62 and the freezing pipe outer pipe 61 .

[0087] An annular end cover 63 is provided between one end of the freezing pipe outer tube 61 and the freezing pipe inner tube 62 . A liquid inlet joint 631 is provided on the annular end cover 63 . The liquid inlet joint 631 is connected to the liquid supply pipe 9 .

[0088] One end of the freezing tube inner tube 62 is provided with a freezing tube inner tube sealing cover 64, and the other end of the freezing tube inner tube 62 is provided with an inner tube liquid inlet 621 connected to the annular flow channel 66. The freezing tube inner tube sealing cover 64 is provided with a liquid outlet joint 641, and the liquid outlet joint 641 is connected to the return liquid pipe 10.

[0089] When the freezing pipe 6 is recovered, the freezing pipe outer pipe 61 remains in the freezing borehole 3 , and the freezing pipe inner pipe 62 is pulled out from the freezing pipe outer pipe 61 .

[0090] In order to prevent the freezing pipe 6 from being frozen in the freezing borehole 3 and being difficult to pull out when the freezing pipe 6 is recovered, the freezing pipe 6 in this embodiment adopts the following design scheme:

[0091] The freezing pipe 6 adopts a double-layer design, which includes an inner freezing pipe 62 and an outer freezing pipe 61. The outer freezing pipe 61 is sleeved on the outer side of the inner freezing pipe 62, and an annular flow channel 66 is formed between the inner freezing pipe 62 and the outer freezing pipe 61.

[0092] The length of the inner tube 62 of the freezing tube is shorter than the length of the outer tube 61 of the freezing tube. One end of the inner tube 62 of the freezing tube is the inner tube liquid inlet 621, which extends into the outer tube 61 of the freezing tube and is spaced a preset distance from the bottom plate of the outer tube 61 of the freezing tube, so that the inner tube liquid inlet 621 is connected to the annular flow channel 66.

[0093] An annular end cap 63 is provided between the pipe openings of the freezing pipe outer pipe 61 and the freezing pipe inner pipe 62, and the annular end cap 63 is used to seal the annular flow channel 66. The annular end cap 63 is provided with at least one liquid inlet connector 631 to be connected to the liquid supply pipe 9.

[0094] The pipe opening end of the freezing pipe inner pipe 62 is provided with a freezing pipe inner pipe sealing cover 64 for sealing the pipe opening of the freezing pipe inner pipe 62. The freezing pipe inner pipe sealing cover 64 is provided with a liquid outlet joint 641 for connecting with the liquid return pipe 10.

[0095] In this way, a circuit for the circulation of freezing liquid is formed. The freezing liquid enters the annular flow channel 66 through the liquid inlet joint 631, exchanges heat with the surrounding geology through the outer tube 61 of the freezing tube to achieve freezing, then enters the inner tube 62 of the freezing tube through the inner tube liquid inlet 621, and finally flows back to the return liquid pipe 10 from the liquid outlet joint 641.

[0096] When the freezing pipe 6 is recovered, the outer pipe 61 of the freezing pipe is difficult to be pulled out due to freezing, so the outer pipe 61 of the freezing pipe is left in the freezing borehole 3, and the inner pipe 62 of the freezing pipe is pulled out or extracted from the outer pipe 61 of the freezing pipe, thereby realizing the recovery and reuse of the inner pipe 62 of the freezing pipe.

[0097] In one embodiment, if Figure 4 As shown, a joint groove 642 is provided on the circumferential surface of the liquid outlet joint 641 for connecting the rope of the traction device to facilitate pulling or extracting the freezing pipe inner pipe 62 from the freezing pipe outer pipe 61. The traction device can adopt a winch mechanism with a rope.

[0098] In one embodiment, if Figure 4-5 As shown, a plurality of support brackets 65 are provided at intervals on the freezing pipe inner tube 62 , and the support brackets 65 are located in the annular flow channel 66 and are slidably connected to the freezing pipe outer tube 61 .

[0099] In this embodiment, the freezing pipe inner tube 62 is supported in the freezing pipe outer tube 61 by a plurality of support brackets 65 , which is conducive to the coaxial arrangement of the freezing pipe inner tube 62 and the freezing pipe outer tube 61 .

[0100] The support bracket 65 is slidably connected to the outer tube 61 of the freezing pipe, and can be assembled and connected through a slide groove, a slider, etc., and can also be equipped with rollers to facilitate pulling or extracting the inner tube 62 of the freezing pipe from the outer tube 61 of the freezing pipe.

[0101] In one of the embodiments, step S02 also includes: drilling a plurality of temperature measuring holes from the tunnel 1 to the wind oxidation zone area 2, so that a temperature measuring tool can be inserted into the temperature measuring holes for temperature measurement, thereby determining whether the wind oxidation zone area 2 is frozen.

[0102] In one embodiment, if Figure 2-3 As shown, the freezing borehole 3, the heat-insulating borehole 5 and the pressure-relieving borehole 4 extend obliquely upwards respectively.

[0103] Step S02 also includes: drilling multiple rows of freezing boreholes 3 arranged at intervals up and down and multiple rows of insulation boreholes 5 arranged at intervals up and down from the tunnel 1 to the wind oxidation zone area 2.

[0104] There is a row of insulation drilled holes 5 between every two rows of freezing drilled holes 3 in the vertical direction and the horizontal direction.

[0105] In the vertical direction, the drilling angle of the single row of freezing drill holes 3 is gradually increased in increments of 1° until it reaches the top of the wind oxidation zone area 2. In the direction of advancement along the coal mining working face, multiple rows of freezing drill holes 3 are provided in the wind oxidation zone area 2 to freeze and reinforce the wind oxidation zone area 2 as a whole.

[0106] The heat preservation borehole 5 can be arranged along with the freezing borehole 3. The freezing borehole 3 can also be designed with plum blossom piles.

[0107] The number of the pressure relief boreholes 4 is less than the thermal insulation boreholes 5 , and a pressure relief borehole 4 can be arranged between a plurality of freezing boreholes 3 and thermal insulation boreholes 5 .

[0108] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0109] The above are only the principles and preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several other modifications can be made based on the principles of the present invention, which should also be considered as the protection scope of the present invention.

Claims

1. A method for coal mining through a wind oxidation zone using a freezing method, characterized in that: The steps include: S01: Use geophysical exploration and drilling to detect the wind oxidation zone in the coal seam; S02: Drilling a plurality of freezing boreholes, heat-insulating boreholes and pressure-relieving boreholes from the tunnel to the wind-oxidized zone area; S03: Arrange a freezing liquid supply device, a liquid supply pipe, a liquid return pipe, a liquid supply pump and a reflux pump in the tunnel; Install a freezing pipe in each of the freezing boreholes, connect the liquid inlet of each freezing pipe to the liquid supply pipe, and connect the liquid outlet of each freezing pipe to the liquid return pipe; S04: using the freezing liquid supply device to supply freezing liquid into the freezing pipe to freeze the wind oxidation zone area; S05: the freezing liquid supply device stops supplying the freezing liquid and recovers the freezing liquid in the freezing pipe; S06: installing an insulation pipe in each of the insulation boreholes, wherein liquid ammonia is stored in the insulation pipe, and one end of the insulation pipe extends into the tunnel for heat exchange; S07: The coal mining working face mines the wind oxidation zone along the advancing direction, wherein the insulation pipes are successively recovered ahead of the coal mining working face in the tunnel.

2. The method for coal mining by freezing through a wind oxidation zone according to claim 1, characterized in that: The insulation pipe comprises an insulation pipe inner pipe and an insulation pipe outer pipe sleeved on the insulation pipe inner pipe; The pipe opening of the inner pipe of the thermal insulation pipe is provided with an inner pipe sealing cover, and liquid ammonia is stored in the inner pipe of the thermal insulation pipe; The inner tube of the thermal insulation pipe is longer than the outer tube of the thermal insulation pipe, and one end of the inner tube of the thermal insulation pipe having the inner tube sealing cover of the thermal insulation pipe extends out of the outer tube of the thermal insulation pipe; The outer tube of the insulation pipe is inserted into the insulation drilled hole, and the portion of the inner tube of the insulation pipe extending out of the outer tube of the insulation pipe extends into the tunnel; When the insulation pipe is recovered, the outer pipe of the insulation pipe remains in the insulation borehole, and the inner pipe of the insulation pipe is pulled out from the outer pipe of the insulation pipe.

3. The method for coal mining by freezing through a wind oxidation zone according to claim 2, characterized in that: The inner tube sealing cover of the thermal insulation tube is provided with a handle for connecting the rope of the traction equipment.

4. The method for coal mining by freezing through a wind oxidation zone according to claim 2, characterized in that: The outer diameter of the inner tube of the insulation pipe is smaller than the inner diameter of the outer tube of the insulation pipe. A plurality of annular brackets are sleeved on the inner tube of the insulation pipe at intervals. The outer annular surface of the annular brackets is provided with a plurality of balls, and the balls are in contact with the inner surface of the outer tube of the insulation pipe.

5. The method for coal mining by freezing through a wind oxidation zone according to claim 1, characterized in that: After the freezing liquid in the freezing pipe is recovered, the freezing pipe is recovered in the lane.

6. The method for coal mining through a wind oxidation zone by freezing according to claim 5, characterized in that: The freezing pipe comprises a freezing pipe inner pipe and a freezing pipe outer pipe sleeved on the freezing pipe inner pipe, and an annular flow channel is formed between the freezing pipe inner pipe and the freezing pipe outer pipe; An annular end cover is provided between the outer tube of the freezing tube and one end of the inner tube of the freezing tube, and a liquid inlet joint is provided on the annular end cover, and the liquid inlet joint is connected to the liquid supply pipe; A freezing pipe inner pipe sealing cover is provided at one end of the freezing pipe inner pipe, an inner pipe liquid inlet communicating with the annular flow channel is provided at the other end of the freezing pipe inner pipe, a liquid outlet joint is provided on the freezing pipe inner pipe sealing cover, and the liquid outlet joint is connected to the liquid return pipe; When the freezing pipe is recovered, the outer pipe of the freezing pipe remains in the freezing borehole, and the inner pipe of the freezing pipe is pulled out from the outer pipe of the freezing pipe.

7. The method for coal mining by freezing through a wind oxidation zone according to claim 6, characterized in that: A joint groove is provided on the circumferential surface of the liquid outlet joint for connecting the rope of the traction device.

8. The method for coal mining through a wind oxidation zone by freezing according to claim 6, characterized in that: A plurality of support brackets are arranged at intervals on the inner tube of the freezing tube. The support brackets are located in the annular flow channel and are slidably connected to the outer tube of the freezing tube.

9. The method for coal mining by freezing through a wind oxidation zone according to claim 1, characterized in that: The step S02 also includes: drilling a plurality of temperature measuring holes from the tunnel to the wind oxidation zone area.

10. The method for coal mining through a wind oxidation zone by freezing according to claim 1, characterized in that: The freezing borehole, the heat-insulating borehole and the pressure-relieving borehole extend obliquely upward respectively; The step S02 further includes: drilling a plurality of rows of freezing boreholes and a plurality of rows of insulation boreholes arranged at intervals from the tunnel to the wind oxidation zone; Wherein, in the vertical direction and the horizontal direction, there is a row of the insulation drilled holes between every two rows of the freezing drilled holes.

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