Method for increasing lump coal rate

Abstract

The present invention relates to the technical field of coal mining, and specifically relates to a method for increasing the lump coal rate. The method includes: arranging a plurality of drilling positions on the working face of the coal seam according to the cutting seam distance of the high-pressure jet cutting equipment for cutting the coal seam, and the relationship between the preset distance between adjacent drilling positions and the cutting seam distance satisfies: A is the preset distance, B is the cutting seam distance, and the cutting seam distance is the distance from the edge of the cutting seam to the center of the drilling position; drilling at the drilling positions along the vertical direction of the working face to obtain a plurality of drill holes corresponding to the drilling positions one by one; using the high-pressure jet cutting equipment to reciprocally cut the coal seam along the axial direction of the drill hole in two mutually orthogonal axial planes of the drill hole to obtain two mutually orthogonal axial cutting seams; using the high-pressure jet cutting equipment to perform self-rotation cutting on the coal seam in the radial plane of the drill hole to obtain a radial cutting seam; using an explosive to blast the coal seam to expand the cutting seam distance so that the radial cutting seams and the axial cutting seams between the plurality of drill holes are interconnected.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, and particularly relates to a method for improving lump coal rate. Background Art

[0002] With the continuous improvement of coal mining technology, the requirement for lump coal rate is getting higher and higher. Among them, the price of lump coal in commercial coal is generally much higher than that of slack coal. Improving the lump coal rate is also an effective way to increase the income of coal enterprises.

[0003] In related technologies, the means for improving the lump coal rate mainly include: changing the shapes of the cutting head and picks of the shearer, adjusting the drum rotation speed and haulage speed of the shearer, and using a single coal seam blasting or hydraulic fracturing means to increase the crack development in the coal body. The above methods for improving the lump coal rate have no obvious effect, and there is an urgent need to develop an efficient method for improving the lump coal rate. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in related technologies to some extent. For this purpose, an embodiment of the present invention provides a method for improving the lump coal rate, which includes: arranging a plurality of drilling positions on the working face of the coal seam according to the cutting distance of the high-pressure jet cutting equipment for cutting the coal seam, and the relationship between the preset distance between adjacent drilling positions and the cutting distance satisfies:

[0005]

[0006] Wherein,

[0007] A is the preset distance, B is the cutting distance, and the cutting distance is the distance from the edge of the cut to the center of the drilling position;

[0008] Drilling is carried out at the drilling positions along the vertical direction of the working face to obtain a plurality of drill holes corresponding to the drilling positions one by one;

[0009] Using the high-pressure jet cutting equipment to cut the coal seam back and forth along the axial direction of the drill hole in two mutually orthogonal axial planes of the drill hole to obtain two mutually orthogonal axial cut seams;

[0010] Using the high-pressure jet cutting equipment to cut the coal seam rotationally in the radial plane of the drill hole to obtain a radial cut seam; and

[0011] Using an explosive to blast the coal seam to expand the cutting distance, so that the radial cut seams and axial cut seams between the plurality of drill holes are interconnected.

[0012] The method for increasing the lump coal rate in the embodiment of the present invention is mainly to reasonably arrange the drill positions on the working surface of the coal seam, and then drill, cut and blast the coal seam in sequence, so as to form multiple mutually orthogonal and mutually interpenetrating cuts in the coal seam. It should be noted that since the front ends of the multiple cuts are concentrated, the detonation wave generated by the blasting can expand along the multiple cuts, so that the cuts that are completely connected to each other are formed in the coal seam, that is, the coal body in the coal seam is divided into multiple separate blocks. The method for increasing the lump coal rate can effectively increase the lump coal rate. When the coal mining machine performs coal mining operations on the coal seam, if the coal seam is not cut into multiple separate blocks, the forces existing between the coal bodies in the coal seam will cause the coal mining machine to need a greater force to cut the coal, and the squeezing between the coal bodies will produce a large amount of coal powder or coal slag. If the coal body in the coal seam is divided into multiple separate blocks, when the coal mining machine operates on the coal body that has been divided into multiple separate blocks, there is no internal force between the separate blocks, and the mutual squeezing between the separate blocks will only produce a small amount of coal powder and coal slag, thereby increasing the lump coal rate.

[0013] Optionally, the coal seam is cut back and forth along the axial direction of the borehole using a high-pressure jet cutting device in two mutually orthogonal axial planes of the borehole to obtain two mutually orthogonal axial cuts, including:

[0014] The high-pressure jet cutting equipment cuts the coal seam back and forth in a uniform reciprocating working state.

[0015] Optionally, the high-pressure jet cutting device is used to perform self-rotation cutting on the coal seam in the radial plane of the borehole to obtain radial cutting seams, including:

[0016] The high-pressure jet cutting equipment is used to perform self-rotation cutting on the coal seam in the axial direction at preset distances in sequence to obtain multiple radial cuts.

[0017] Optionally, the preset distances between adjacent radial slits in the plurality of radial slits are all the same.

[0018] Optionally, a preset distance between adjacent radial slits among the plurality of radial slits is 1.5-2.5 m.

[0019] Optionally, the high-pressure jet cutting device is used to perform self-rotation cutting on the coal seam in the radial plane of the borehole to obtain radial cutting seams, including:

[0020] The high-pressure jet cutting equipment performs self-rotation cutting on the coal seam in a uniformly rotating working state.

[0021] Optionally, the high-pressure jet slitting device has a jetting mode of jetting in a radial direction of the borehole in a direction away from the center of the borehole, and has at least two jetting directions that are orthogonal to each other in the same radial plane.

[0022] Optionally, the high-pressure jet slitting device is a high-pressure jet drill pipe with adjustable water pressure and adjustable nozzle diameter.

[0023] Optionally, the slitting distance of the high-pressure jet slitting device is 1.5 - 2.5 m, and the preset spacing between adjacent drilling positions is 3 - 5 m. Description of the Drawings

[0024] Figure 1 Schematically shows a flowchart of a method for increasing lump coal rate according to an embodiment of the present invention.

[0025] Figure 2 Schematically shows a flowchart of another method for increasing lump coal rate according to an embodiment of the present invention.

[0026] Figure 3 Schematically shows a schematic diagram of drilling and slitting according to an embodiment of the present invention.

[0027] Reference Signs: 1 - Drilling Hole, 2 - Radial Slit, 3 - Axial Slit, A - Preset Spacing, B - Slitting Distance, X - Unconnected Area. Detailed Description of the Embodiment

[0028] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] The method for increasing lump coal rate in the embodiments of the present invention includes:

[0030] According to the slitting distance B of the high-pressure jet slitting device for cutting the coal seam, a plurality of drilling positions are arranged on the working face of the coal seam. Among them, the relationship between the preset spacing A between adjacent drilling positions and the slitting distance B satisfies: , where A is the preset spacing, B is the slitting distance, and the slitting distance B is the distance from the edge of the slit to the center of the drilling position.

[0031] Drilling is carried out at the drilling positions along the vertical direction of the working face to obtain a plurality of drilling holes 1 corresponding one by one to the drilling positions. In two mutually orthogonal axial planes of the drilling hole 1, the high-pressure jet slitting device is used to cut the coal seam back and forth along the axis of the drilling hole 1 to obtain two mutually orthogonal axial slits 3.

[0032] In the radial plane of the drilling hole, the high-pressure jet slitting device is used to cut the coal seam by rotation to obtain a radial slit 2.

[0033] The coal seam is blasted with explosives to expand the slitting distance B, so that the radial slits 2 and axial slits 3 between the plurality of drilling holes 1 are interconnected.

[0034] The method for increasing the lump coal rate in the embodiment of the present invention mainly comprises arranging drill positions on the working surface of the coal seam, and then drilling, cutting and blasting the coal seam in sequence to form a plurality of mutually orthogonal and mutually completely connected slits in the coal seam. In addition, since the front ends of the plurality of slits are concentrated, the detonation wave generated by the blasting can be extended along the plurality of slits, so that the slits in the coal seam are mutually completely connected, that is, the coal body in the coal seam is divided into a plurality of separate blocks. When the coal mining machine performs coal mining operations on the coal seam, if the coal seam is not cut into a plurality of separate blocks, the forces existing inside the coal body in the coal seam cause the coal mining machine to need a greater force to cut the coal, and the extrusion between the coal bodies will produce a large amount of coal powder or coal slag. If the coal body in the coal seam is divided into a plurality of separate blocks, when the coal mining machine operates on the blocks that have been divided into a plurality of separate blocks, there is no internal force between the separate blocks, and the mutual extrusion between the separate blocks will only produce a small amount of coal powder and coal slag, thereby increasing the lump coal rate.

[0035] It should be noted that, in the present invention, the working surface of the coal seam refers to the mining wall of the two drifts, not the supporting working surface of the hydraulic support and the working surface of the coal mining machine. In the embodiment of the present invention, the working surface of the coal seam is not the same plane as the supporting working surface of the hydraulic support and the coal mining working surface of the coal mining machine. Figure 3 As shown, attached Figure 3 represents the working face of the coal seam in the embodiment of the present invention, wherein the vertical direction along the working face refers to the direction perpendicular to Figure 3 direction, and the vertical direction is perpendicular to the working surface; two mutually orthogonal axial planes refer to the axial planes being perpendicular to the working surface, and the axial planes include the axis of the borehole 1; the radial plane of the borehole 1 refers to the radial plane being parallel to the working surface.

[0036] like Figure 1 As shown, the method includes steps S110 to S150.

[0037] In step S110, according to the slitting distance B of the coal seam cut by the high-pressure jet slitting equipment, multiple drill positions are arranged on the working surface of the coal seam, wherein the relationship between the preset spacing A between adjacent drill positions and the slitting distance B satisfies:

[0038]

[0039] Wherein, A is the preset spacing, B is the slit distance, and the slit distance A is the distance from the edge of the slit to the center of the drill position.

[0040] Specifically, when the cutting seam distance B of the high-pressure jet cutting equipment for cutting coal seams is determined, multiple drilling positions can be arranged on the working face of the coal seam. That is to say, the arrangement of the drilling positions is determined according to the cutting seam distance B. If the preset distance A between two drilling positions is less than times the cutting seam distance B, the high-pressure jet cutting equipment can make the cutting seams between the drilling positions directly communicate with each other, so that the coal seam forms multiple separate blocks. However, the smaller the preset distance A between the drilling positions, the more drilling positions are arranged on the same working face of the coal seam, resulting in a greater workload for subsequent drilling and a greater workload for subsequent cutting by the high-pressure jet cutting equipment. In the present invention, the preset distance A between adjacent drilling positions and the cutting seam distance B are: , mainly to increase the preset distance A between the drilling positions. The larger the preset distance A, the fewer drilling positions are arranged on the same working face of the coal seam, making the subsequent workload of drilling and cutting less, thereby not only improving the lump coal rate but also increasing the work efficiency.

[0041] In summary, when arranging the drilling positions, limiting the relationship between the preset distance A between adjacent drilling positions and the cutting seam distance B can not only ensure the lump coal rate but also reduce the workload of drilling and cutting.

[0042] It should be noted that in the attached Figure 3 As shown, the high-pressure jet cutting equipment continuously sprays water cutting knives in the radial direction of the borehole 1 to continuously cut the coal body. Among them, the distance from the center of the borehole 1 to the farthest distance where the water cutting knife can cut the coal body is the cutting seam distance B.

[0043] In some embodiments, the arrangement of the drilling positions is mainly determined according to the physical parameters of the coal body.

[0044] Specifically, the preset distance A between the drilling positions is negatively correlated with the hardness of the coal body, that is, the greater the hardness of the coal body, the smaller the arrangement of the drilling intervals. When other factors do not affect the arrangement of the drilling positions, the greater the hardness of the coal body, the smaller the cutting seam distance B of the high-pressure jet cutting equipment for cutting the coal seam. Among them, the cutting seam distance B of the high-pressure jet cutting equipment is 1.5 - 2.5 m, and the preset distance A between adjacent drilling positions is 3 - 5 m.

[0045] In some embodiments, the jetting mode of the high-pressure jet cutting equipment is to jet in the radial direction of the borehole 1 along the direction away from the center of the borehole 1, and there are at least two jetting directions orthogonal to each other in the same radial plane.

[0046] Specifically, the jet direction of the high-pressure jet slitting device is to cut slits along the radial direction of the borehole 1. That is to say, when the high-pressure jet slitting device is cutting the coal seam, the high-pressure jet slitting device can form a water cutting knife in the radial direction of the borehole 1 and then cut the coal seam. In addition, the high-pressure jet slitting device can form at least two water cutting knives to improve the working efficiency of the high-pressure jet slitting device in cutting slits in the coal seam. Among them, the jet direction of the high-pressure jet slitting device can be selected according to the requirements of slit cutting. For example, as Figure 3 shown, for the borehole 1 in the middle of the coal seam, the borehole 1 is adjacent to the other four boreholes 1 (that is, four slits are required). In order to improve the slit cutting working efficiency of the high-pressure jet slitting device, the high-pressure jet slitting device can simultaneously cut the coal seam in four directions through the water cutting knife. In addition, for the borehole 1 at the edge of the coal seam, some boreholes 1 are adjacent to the other three boreholes 1, and some boreholes 1 are adjacent to the other two boreholes 1. The high-pressure jet slitting device can simultaneously cut the coal seam in three directions or two directions through the water cutting knife to improve the slit cutting working efficiency of the high-pressure jet slitting device.

[0047] In some embodiments, the high-pressure jet slitting device is a high-pressure jet drill pipe with adjustable water pressure and adjustable nozzle diameter.

[0048] Specifically, when the water pressure of the high-pressure jet drill pipe is determined, that is, the water cutting knife formed by the high-pressure jet drill pipe is determined, and then the slit distance B in the coal seam can be determined. In this regard, the water pressure of the high-pressure jet drill pipe can indirectly change the slit distance B in the coal seam. In addition, the diameter of the water cutting knife sprayed by the high-pressure jet drill pipe is related to the diameter of the nozzle, that is, the larger the diameter of the nozzle, the wider the width of the slit in the coal seam.

[0049] In some embodiments, determining the slit distance B of the high-pressure jet slitting device for cutting the coal seam is mainly tested by on-site experimental means.

[0050] For example, through jet tests in the coal body at the goaf side, observe the slit distance B when the diameters of the jet holes are 1 mm, 2 mm, 3 mm, 4 mm respectively and the jet times are 30 min and 60 min respectively, so as to determine the relationship between the slit distance B of the high-pressure jet slitting device for cutting the coal seam and the diameter of the jet hole and the jet time.

[0051] As Figure 1 shown, in step S120, drilling is carried out at the drilling position along the perpendicular direction of the working face to obtain a plurality of boreholes 1 corresponding to the drilling positions one by one.

[0052] Specifically, on a working face where the drilling positions have been arranged, drilling is carried out on the coal seam along the perpendicular direction of the working face. This drilling direction is conducive to workers installing auxiliary equipment for assisting drilling. Additionally, if the coal seam is not drilled along the perpendicular direction of the working face, the higher the drilling depth, the higher the performance requirements for the drilling equipment, resulting in higher drilling costs. Therefore, drilling on the coal seam along the perpendicular direction of the working face can effectively reduce the drilling cost.

[0053] As Figure 1 shown, in step S130, in two mutually orthogonal axial planes of borehole 1, the coal seam is reciprocally cut along the axial direction of the borehole using a high-pressure jet slitting device to obtain two mutually orthogonal axial slits 3.

[0054] Specifically, the water cutting knife ejected by the high-pressure jet slitting device cuts the coal seam in two mutually orthogonal axial planes of borehole 1. It should be noted that the water cutting knife of the high-pressure jet slitting is ejected radially towards borehole 1. When the water cutting knife moves along the axial direction of borehole 1, the water cutting knife can cut an axial slit 3 in the axial plane of borehole 1. It should be noted that within the same axial plane of borehole 1, the water cutting knife needs to cut the coal seam multiple times to make the slit in the coal seam reach the set slit distance B. That is to say, when the water cutting knife cuts the coal seam for the first time, the actual distance of the slit formed in the coal seam does not reach the set slit distance B. Therefore, the water cutting knife needs to reciprocally cut in the coal seam to make the slit in the coal seam reach the set slit distance B. Additionally, the reciprocal cutting of the water cutting knife in the coal seam also helps to clean the coal slag and sundries in the slit, etc.

[0055] As Figure 2 shown, in step S231, in two mutually orthogonal axial planes of borehole 1, the coal seam is reciprocally cut along the axial direction of borehole 1 using a high-pressure jet slitting device, and obtaining two mutually orthogonal axial slits includes: the high-pressure jet slitting device reciprocally cuts the coal seam in a working state of uniform speed back and forth.

[0056] Specifically, during the drilling process, uniform feed should be ensured, which can guarantee the same slit distance at different positions, facilitating the uniform expansion of the slit by blasting in the later stage, thereby achieving the purpose of artificially controlling the fracture depth.

[0057] As Figure 1 shown, in step S140, in the radial plane of borehole 1, the coal seam is rotationally cut using a high-pressure jet slitting device to obtain a radial slit 2.

[0058] Specifically, the water cutting knife ejected by the high-pressure jet slitting equipment cuts the coal seam in the radial plane of the borehole 1. It should be noted that the water cutting knife of the high-pressure jet slitting is ejected towards the radial direction of the borehole 1. When the high-pressure jet slitting equipment rotates in the borehole 1, the water cutting knife is equivalent to a rotating circular cutting knife, continuously cutting the coal seam in the radial plane of the borehole 1 to obtain the radial slit 2. It should be noted that in the radial plane of the borehole 1, the water cutting knife needs to cut the coal seam multiple times to reach the set slit distance B in the coal seam. That is to say, when the water cutting knife cuts the coal seam for the first time, the actual distance of the slit formed in the coal seam does not reach the set slit distance B. Therefore, the high-pressure jet slitting equipment needs to rotate multiple times in the coal seam to cut the coal seam so that the slit in the coal seam reaches the set slit distance B. Among them, the water cutting knife rotating and cutting the coal seam multiple times also helps to clean the coal slag and sundries in the slit, etc.

[0059] As Figure 1 shown, in step S241a, using the high-pressure jet slitting equipment to rotate and cut the coal seam in the radial plane of the borehole 1 to obtain the radial slit 2 includes: using the high-pressure jet slitting equipment to rotate and cut the coal seam at a preset distance along the axial direction in sequence to obtain a plurality of radial slits 2.

[0060] Specifically, in the direction perpendicular to the working face, the thickness of the coal seam in each coal mine is different. In addition, the thickness of the coal seam in the same coal mine may also be different, even the thickness of the coal seam located in the same working face is different. That is to say, some coal seams are thin, and only one radial slit 2 needs to be cut in the coal seam in one borehole 1. Some coal seams are thick, and multiple radial slits need to be cut in the coal seam in one borehole 1.

[0061] It should be noted that if there is only one radial slit in the coal seam, the preset distance can be understood as the distance from the working face of the coal seam to the radial slit. If there are multiple radial slits in the coal seam, the preset distance is both the distance from the working face of the coal seam to the adjacent radial slit and the distance between adjacent radial slits. Among them, the distance between the preset distances of each adjacent radial slit can be different.

[0062] In some embodiments, the preset distances between adjacent radial slits among the plurality of radial slits are all the same.

[0063] Specifically, the coal bodies in most coal seams are uniform and their various physical properties do not differ much. Therefore, radial slits are formed in the coal seam at the same preset distance, so that the coal bodies in the coal seam are divided into multiple separate block bodies of the same size. Among them, the preset distance between adjacent radial slits among the plurality of radial slits is 1.5 - 2.5 m.

[0064] AsFigure 2 As shown, in step S242b, the coal seam is rotationally cut in the radial plane of borehole 1 by using a high-pressure jet slitting device, and the obtained radial slit 2 includes: the high-pressure jet slitting device rotationally cuts the coal seam 3 in a working state of rotating at a constant speed.

[0065] Specifically, when the high-pressure jet slitting device rotationally cuts the coal seam 3 in a working state of rotating at a constant speed, the shape of the radial slit 2 can be ensured to be circular, which is beneficial to the later uniform expansion of the slit by blasting, so as to achieve the purpose of artificially controlling the crack depth.

[0066] As Figure 1 shown, in step S150, the coal seam is blasted by using an explosive to expand the slit distance, so that the radial slits and axial slits between multiple boreholes are interconnected.

[0067] Specifically, as Figure 3 shown, when the preset distance A between drilling positions is greater than times the slit distance B, there is an unconnected area X between the four drilling positions, that is, the four drilling positions are not interconnected with each other. The coal seam is blasted by using an explosive, and the detonation wave generated by the blasting can expand along multiple slits, so that the slits in the coal seam are completely interconnected with each other.

[0068] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0069] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0070] In the present invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0072] In the present invention, terms such as "an embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0073] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A method for increasing the lump coal rate, comprising: According to the slotting distance of the high-pressure jet slotting equipment for cutting the coal seam, a plurality of drilling positions are arranged on the working face of the coal seam. The working face of the coal seam refers to the mining rib of the two gateways, and the relationship between the preset distance between adjacent drilling positions and the slotting distance satisfies: Wherein, A is the preset distance, B is the slotting distance, and the slotting distance is the distance from the edge of the slot to the center of the drilling position; Drilling is carried out at the drilling positions along the vertical direction of the working face to obtain a plurality of drill holes corresponding to the drilling positions one by one; In two mutually orthogonal axial planes of the drill hole, the high-pressure jet slotting equipment is used to cut the coal seam back and forth along the axis of the drill hole to obtain two mutually orthogonal axial slots; In the radial plane of the drill hole, the high-pressure jet slotting equipment is used to cut the coal seam by rotation to obtain a radial slot; and An explosive is used to blast the coal seam to expand the slotting distance so that the radial slots and the axial slots between the plurality of drill holes are interconnected.

2. The method for increasing the lump coal rate according to claim 1, wherein, The step of using the high-pressure jet slotting equipment to cut the coal seam back and forth along the axis of the drill hole in two mutually orthogonal axial planes of the drill hole to obtain two mutually orthogonal axial slots includes: The high-pressure jet slotting equipment performs the back-and-forth cutting on the coal seam in a uniformly reciprocating working state.

3. The method for increasing the lump coal rate according to claim 1, wherein, The step of using the high-pressure jet slotting equipment to cut the coal seam by rotation in the radial plane of the drill hole to obtain a radial slot includes: The high-pressure jet slotting equipment is used to perform the rotational cutting on the coal seam at preset distances along the axis in sequence to obtain a plurality of the radial slots.

4. The method for increasing the lump coal rate according to claim 3, wherein, The preset distances between adjacent radial slots among the plurality of radial slots are the same.

5. The method for increasing the lump coal rate according to claim 4, wherein, The preset distance between adjacent radial slots among the plurality of radial slots is 1.5 - 2.5 m.

6. The method for increasing the lump coal rate according to claim 1, wherein, The step of using the high-pressure jet slotting equipment to cut the coal seam by rotation in the radial plane of the drill hole to obtain a radial slot includes: The high-pressure jet slotting equipment performs the rotational cutting on the coal seam in a uniformly rotating working state.

7. The method for increasing the lump coal rate according to any one of claims 1 - 6, wherein, The jetting mode of the high-pressure jet slotting equipment is to jet in the radial direction of the drill hole along the direction away from the center of the drill hole, and has at least two jetting directions that are mutually orthogonal in the same radial plane.

8. The method for increasing the lump coal rate according to any one of claims 1 - 6, wherein, The high-pressure jet slotting equipment is a high-pressure jet drill rod with adjustable water pressure and adjustable nozzle diameter.

9. The method for increasing the lump coal rate according to any one of claims 1 - 6, wherein, The slotting distance of the high-pressure jet slotting equipment is 1.5 - 2.5 m, and the preset distance between adjacent drilling positions is 3 - 5 m.

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