Top coal top plate fracturing method for improving top coal recovery rate in initial mining period of working face

Abstract

The invention provides a top coal top plate fracturing method for improving the top coal recovery rate in the initial mining period of a working face, and belongs to the field of coal mining. The method comprises the following steps that S100, a plurality of non-directional short holes are formed in a top coal seam along the inner side wall of an open-off cut through a non-directional drilling machine; s200, a directional long drilling machine is adopted to form a plurality of directional holes in the rock plate rock stratum in the cut hole direction along the side wall of the crossheading, and the directional holes are arranged in a triangular or rectangular mode; s300, directional jet flow fracturing is conducted on the multiple directional holes to form at least three directional cracks, and the at least three directional cracks are communicated clockwise and distributed in a polygonal mode to form a rock block; and S400, pushing mining is conducted on the fully mechanized caving face, and coal mining is completed. The problems that in the prior art, top coal is high in hardness and large in mining difficulty, a top plate is usually stable but not prone to collapse, and a large-area suspended roof is possibly formed are solved. The technical effect that the top coal can rapidly and easily collapse is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a top coal roof fracturing method for improving the top coal recovery rate during initial mining of a working face. Background Art

[0002] The hard and thick top coal fully mechanized top coal caving working face refers to the working face that uses comprehensive mechanized top coal caving mining technology to mine thick coal seams with hard characteristics. The coal seams are thick, the top coal is hard, the mining is difficult, the roof is usually stable, but not easy to collapse, and a large area of ​​hanging roof may be formed, especially during the initial mining period, because the initial pressure step of the roof is long, the top coal is not under the pressure of rock strata, which makes it difficult for the top coal to collapse, and the recovery rate is low, resulting in a waste of coal resources. Summary of the invention

[0003] The present invention provides a top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face, so as to solve the defects in the prior art that the top coal has high hardness, is difficult to mine, the roof is usually relatively stable but not easy to collapse, and a large area of ​​hanging roof may be formed, so that the top coal can collapse quickly and relatively easily.

[0004] The present invention provides a top coal roof fracturing method for improving the top coal recovery rate during the initial mining of a working face, comprising the following steps: Step S100: using a non-directional drilling rig to drill a plurality of non-directional short holes along the inner wall of the cut hole toward the top coal seam; Step S200: using a directional long drill to drill a plurality of directional holes along the side wall of the trench in the direction of the cutting eye and towards the rock slab and rock layer, and the plurality of directional holes are arranged in a triangular or rectangular shape; Step S300: performing directional jet fracturing on a plurality of directional holes to form at least three directional fractures, wherein the at least three directional fractures are connected clockwise and arranged in a polygonal form to form rock blocks; Step S400: Push mining is carried out in the fully mechanized caving working face, and coal mining is completed.

[0005] According to the top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face of the present invention, a non-directional short hole is formed in the top coal seam by using a non-directional drilling rig in the cut eye. Since the non-directional short hole construction is flexible, the drilling density and the fracturing density are large, the non-directional short hole dense fracturing can form a dense seam network, fully destroy the top coal, directly reduce the size of the top coal, and thereby reduce the difficulty of top coal collapse.

[0006] By setting up directional cracks through directional holes and constant-pressure jet fracturing, it is possible to form large rock masses, i.e. rock blocks, above the top coal. After the fully-mechanized caving working face starts to push and mine, the rock blocks will rotate and fall in time due to the effect of gravity, acting on the top coal seam, further destroying the integrity of the top coal seam, allowing the top coal to collapse quickly and relatively easily, thereby improving the top coal recovery rate during the initial mining period.

[0007] By complementing the advantages of non-directional short holes and directional holes, in space, the non-directional short holes 8 can weaken the low-level top coal seam and form relatively dense cracks. The directional holes and directional cracks can cooperate to weaken the high-level roof and form large active rock blocks, thereby ensuring the efficiency of top coal collapse in the top coal seam.

[0008] In addition, the top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to the present invention may also have the following additional technical features: In some embodiments of the present invention, in step S100, the distance between two adjacent non-directional short holes is 8 meters to 12 meters.

[0009] By adopting the above embodiment, the distance between two adjacent non-directional short holes is 8 meters to 12 meters, which can achieve the simultaneous opening of multiple non-directional short holes while avoiding the intersection between two adjacent non-directional short holes that affects the coal mining effect.

[0010] In some embodiments of the present invention, in step S200, there are three directional holes, and the three directional holes are arranged in a triangle.

[0011] In some embodiments of the present invention, in step S300, the length of the rock block is between 45 meters and 55 meters, and the thickness of the rock block is between 24 meters and 26 meters.

[0012] By adopting the above embodiment, since the jet length of jet fracturing and the depth of the directional hole that can be opened by the directional long drill are limited, in order to ensure construction safety, it is most reasonable to set the length of the rock block to between 5 meters and 55 meters and the thickness of the rock block to between 24 meters and 26 meters. In addition, the length of the rock block is set to between 5 meters and 55 meters, and the thickness of the rock block is between 24 meters and 26 meters, so that push mining can be carried out directly after the rock block is formed. At the same time, multiple non-directional short holes can be continued to be opened on the side wall of the cut eye behind this rock block to form a streamlined coal mining operation, thereby increasing the coal mining speed and efficiency.

[0013] In some embodiments of the present invention, before step S100, a cut is made on the solid coal to obtain a fully-mechanized caving working face, and a non-directional drilling rig and fully-mechanized mining equipment are arranged in the fully-mechanized caving working face.

[0014] In some embodiments of the present invention, a plurality of non-directional short holes are arranged in a straight line or in a rectangular array or a circular array along the fully-mechanized caving working face.

[0015] By adopting the above embodiment, a mesh can be formed by arranging a non-directional short hole array, thereby increasing the efficiency of destroying the top coal seam.

[0016] In some embodiments of the present invention, the depth of each directional hole is greater than the distance between the non-directional short hole at the head end and the non-directional short hole at the tail end of the plurality of non-directional short holes.

[0017] By adopting the above embodiment, the depth of each directional hole is greater than the spacing between the non-directional short hole at the head end and the non-directional short hole at the tail end of the multiple non-directional short holes, so that the rock block can be covered as a whole on the multiple non-directional short holes, so as to fully cooperate with the non-directional short holes to ensure the efficiency and collapse effect of the top coal seam.

[0018] In some embodiments of the present invention, the comprehensive mining equipment includes a coal mining machine, a scraper conveyor, a hydraulic support, a transfer machine and a belt conveyor.

[0019] In some embodiments of the present invention, in step S400, the method for promoting purchase includes the following steps: Step S410: using a coal mining machine to break and load coal; Step S420: using a scraper conveyor to transport the coal taken by the coal mining machine to the exit of the fully mechanized caving working face; Step S430: using a transfer machine to transfer the coal at the exit of the fully mechanized caving working face to a belt conveyor; Step S440: Use a belt conveyor to transport the coal from the exit of the fully mechanized caving working face to the ground, and coal mining is completed.

[0020] By adopting the above-mentioned embodiment, the coordinated arrangement of the coal mining machine, the scraper conveyor, the hydraulic support, the transfer machine and the belt conveyor can smoothly collect and transport the coal to the outside to ensure that the subsequent coal mining work is carried out quickly and smoothly.

[0021] In some embodiments of the present invention, a working surface support is provided in the incision.

[0022] By adopting the above embodiment, the setting of the working surface support can ensure the stability of the top plate of the cutting eye, thereby ensuring safety.

[0023] In summary, the present application includes the following beneficial technical effects: by using a non-directional drilling rig in the cutting eye to construct a non-directional short hole in the top coal seam, since the non-directional short hole construction is flexible, the drilling density and the fracturing density are high, the non-directional short hole dense fracturing can form a dense seam network, fully destroy the top coal, directly reduce the size of the top coal, and thereby reduce the difficulty of top coal collapse.

[0024] By setting up directional cracks through directional holes and constant-pressure jet fracturing, it is possible to form large rock masses, i.e. rock blocks, above the top coal. After the fully-mechanized caving working face starts to push and mine, the rock blocks will rotate and fall in time due to the effect of gravity, acting on the top coal seam, further destroying the integrity of the top coal seam, allowing the top coal to collapse quickly and relatively easily, thereby improving the top coal recovery rate during the initial mining period.

[0025] Through the complementary advantages of non-directional short holes and directional holes, in space, non-directional short holes can weaken the low-level top coal seam and form relatively dense cracks, and the combination of directional holes and directional cracks can weaken the high-level roof and form large active rock blocks, thereby ensuring the efficiency of top coal collapse in the top coal seam. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A schematic diagram of a structure in which directional cracks have been formed in a top coal roof fracturing method for improving top coal recovery during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0027] Figure 2 A schematic structural diagram of the completion of directional hole opening and preliminary formation of directional cracks in a top coal roof fracturing method for improving top coal recovery during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0028] Figure 3 A schematic structural diagram of the completion of directional hole opening in a top coal roof fracturing method for improving top coal recovery rate during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0029] Figure 4 A schematic diagram of a side view of a completed directional hole opening in a top coal roof fracturing method for improving top coal recovery during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0030] Figure 5 A first view of non-directional short hole opening of a top coal roof fracturing method for improving top coal recovery during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0031] Figure 6 A second view of non-directional short hole opening of a top coal roof fracturing method for improving top coal recovery during initial mining of a working face according to some embodiments of the present invention is schematically shown.

[0032] Figure 7 The structural diagram of the fracturing of the top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to some embodiments of the present invention is schematically shown.

[0033] Reference numerals: 1. Top coal seam, 2. Rock slab rock layer, 31. First directional hole, 32. Second directional hole, 33. Third directional hole, 41. First directional fracture, 42. Second directional fracture, 43. Third directional fracture, 5. Working face support, 6. Rock block, 7. Strand, 8. Non-directional short hole, 9. Cutting eye. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0035] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0036] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0037] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, then the element described as "below other elements or features" or "below other elements or features" will be subsequently oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be additionally oriented and rotated 90 degrees or in other directions and the spatial relative descriptors used in the text are interpreted accordingly.

[0038] like Figures 1 to 7 As shown, according to an embodiment of the first aspect of the present invention, a top coal roof fracturing method for improving the top coal recovery rate during the initial mining of a working face is proposed, comprising the following steps: Step S100: using a non-directional drilling rig to drill a plurality of non-directional short holes 8 along the inner wall of the cut hole 9 toward the top coal seam 1; Step S200: using a directional long drill to drill a plurality of directional holes along the side wall of the trench in the direction of the cut hole 9 and towards the rock slab and rock layer 2, and the plurality of directional holes are arranged in a triangular or rectangular shape; Step S300: performing directional jet fracturing on a plurality of directional holes to form at least three directional fractures, wherein the at least three directional fractures are connected clockwise and arranged in a polygonal form to form a rock block 6; Step S400: Push mining is carried out in the fully mechanized caving working face, and coal mining is completed.

[0039] In the above embodiment, it should be noted that the number of the plurality of directional holes is three or four. When the number of the directional holes is three, the three directional holes are arranged in the form of an isosceles triangle. When the number of the directional holes is four, the four directional holes are arranged in the form of a rhombus.

[0040] The number of the directional cracks is three or four, and the combination of the three directional cracks and the four image cracks is in a rectangular shape to form a rectangular rock block 6 .

[0041] When the number of directional cracks is three, the three directional cracks are respectively a first directional crack 41, a second directional crack 42 and a third directional crack 43, one end of the second directional crack 42 is connected to the first directional crack 41, and the other end of the second directional crack 42 is connected to the third directional crack 43, and the first directional crack 41 and the third directional crack 43 are both perpendicular to the second directional crack 42.

[0042] The chute 7 and the cut eye 9 are perpendicular to each other.

[0043] Directional jet fracturing uses the existing hydraulic slotted directional hydraulic fracturing device to perform directional jet fracturing on multiple directional holes to form directional cracks; specifically, the working principle of the directional hydraulic fracturing device is: first, the high-pressure sealing capsule, water injector, push rod, water distributor, sealing capsule and other components are connected in a predetermined order. Then, multiple push rods are connected to each other and sent into the directional hole until the predetermined sealing position is reached.

[0044] Then: start the high-pressure water pump and inject high-pressure water into the high-pressure sealing capsule through the high-pressure hose, pressure relief valve, multi-section push rod and other components. With the continuous injection of high-pressure water, the capsule gradually expands and fits tightly on the wall of the directional hole to form a high-pressure sealing environment. At this time, the water pressure P at the outlet is always less than the capsule water pressure P2, and maintains a constant difference P0 (P0 is greater than the capsule expansion pressure P4). When the high-pressure water pressure reaches a certain level, the rock cracks at the borehole wall. As the water pressure continues to increase, the cracks gradually expand and extend in the predetermined direction. During the fracturing process, the pressure of the high-pressure water can be controlled by adjusting the pressure reducing valve to ensure that the cracks can expand stably in the predetermined direction and finally form directional cracks.

[0045] The technical effect achieved by the above embodiment is: a non-directional short hole is formed in the top coal seam by using a non-directional drilling rig in the cutting eye 9. Since the non-directional short hole 8 is flexible in construction, the drilling density and the fracturing density are high, dense fracturing using the non-directional short holes 8 can form a dense seam network, fully destroy the top coal, directly reduce the size of the top coal, and thereby reduce the difficulty of top coal collapse.

[0046] By setting up directional cracks formed by directional holes and constant-pressure jet fracturing, a large rock mass, namely rock block 6, can be formed above the top coal. After the comprehensive caving working face starts to push and mine, the rock block 6 will rotate and collapse in time due to the effect of gravity, acting on the top coal seam 1, further destroying the integrity of the top coal seam 1, so that the top coal can collapse quickly and relatively easily, thereby improving the top coal recovery rate during the initial mining period.

[0047] By complementing the advantages of the non-directional short holes 8 and the directional holes, in space, the non-directional short holes 8 can weaken the low-level top coal seam 1 and form relatively dense cracks, and the directional holes and directional cracks can cooperate to weaken the high-level roof and form large active rock blocks 6, thereby ensuring the efficiency of the top coal collapse of the top coal seam 1.

[0048] Optional, such as Figures 1 to 7 As shown, in step S100, the distance between two adjacent non-directional short holes 8 is 8 meters to 12 meters.

[0049] In the above optional embodiment, it should be noted that the distance between two adjacent non-directional short holes 8 is 10 meters.

[0050] The beneficial effect of the above optional embodiment is that the spacing between two adjacent non-directional short holes 8 is 8 meters to 12 meters, which can realize the simultaneous opening of multiple non-directional short holes 8 while avoiding the intersection between two adjacent non-directional short holes 8 that affects the coal mining effect.

[0051] Optional, such as Figures 1 to 4 As shown, in step S200, there are three directional holes, which are arranged in a triangle.

[0052] In the above optional embodiment, it should be noted that the three directional holes are respectively a first directional hole 31, a second directional hole 32 and a third directional hole 33, the first directional hole 31 and the third directional hole 33 are respectively located on both sides of the second directional hole 32 and the second directional hole 32 is located above the first directional hole 31 and the third directional hole 33 and the first directional hole 31 and the third directional hole 33 are located on the same horizontal plane.

[0053] Optional, such as Figure 1 and Figure 7 As shown, in step S300, the length of the rock block 6 is between 45 meters and 55 meters, and the thickness of the rock block 6 is between 24 meters and 26 meters.

[0054] In the above optional embodiment, it should be noted that the length of the rock block 6 is 50 meters and the thickness of the rock block 6 is 25 meters.

[0055] The beneficial effects of the above optional embodiments are as follows: since the jet length of jet fracturing and the depth of the directional hole that can be opened by the directional long drill are limited, in order to ensure construction safety, it is most reasonable to set the length of the rock block 6 to between 5 meters and 55 meters and the thickness of the rock block 6 to between 24 meters and 26 meters. In addition, the length of the rock block 6 is set to between 5 meters and 55 meters and the thickness of the rock block 6 is between 24 meters and 26 meters, so that push mining can be carried out directly after the rock block 6 is formed. At the same time, multiple non-directional short holes 8 can be continued to be opened on the side wall of the cut eye 9 behind this rock block 6 to form a streamlined coal mining operation, thereby increasing the coal mining speed and efficiency.

[0056] Optional, such as Figures 1 to 7 As shown, before step S100, a cut 9 is made on the solid coal to obtain a fully mechanized caving working face, and non-directional drilling rigs and fully mechanized mining equipment are arranged in the fully mechanized caving working face.

[0057] A plurality of non-directional short holes 8 are arranged in a straight line or in a rectangular array or a circular array along the fully mechanized caving working face.

[0058] In the above optional embodiments, it should be noted that the plurality of non-directional short holes 8 may also be arranged in a rectangular array or a circular array, but all the non-directional short holes 8 do not cross each other.

[0059] The beneficial effect of the above optional embodiment is that a mesh can be formed by arranging the non-directional short holes 8 in an array, thereby increasing the efficiency of destroying the top coal seam.

[0060] Optional, such as Figure 4 As shown, the depth of each directional hole is greater than the distance between the non-directional short hole 8 at the head end and the non-directional short hole 8 at the tail end of the plurality of non-directional short holes.

[0061] In the above optional embodiment, it should be noted that the non-directional short holes 8 are drilled in groups, and a group of non-directional short holes 8 is formed every time a certain distance of coal is mined to ensure construction efficiency.

[0062] The beneficial effect of the above optional embodiment is that the depth of each directional hole is greater than the spacing between the non-directional short hole 8 at the head end and the non-directional short hole 8 at the tail end of the multiple non-directional short holes, so that the rock block 6 can be covered as a whole on the multiple non-directional short holes 8, so as to fully cooperate with the non-directional short holes 8 to ensure the efficiency and collapse effect of the top coal seam 1.

[0063] Optional, such as Figures 1 to 3 As shown, the comprehensive mining equipment includes coal mining machine, scraper conveyor, hydraulic support, transfer machine and belt conveyor.

[0064] Optional, such as Figure 2 and Figure 3 As shown, in step S400, the method for promoting purchase includes the following steps: Step S410: using a coal mining machine to break and load coal; Step S420: using a scraper conveyor to transport the coal taken by the coal mining machine to the exit of the fully mechanized caving working face; Step S430: using a transfer machine to transfer the coal at the exit of the fully mechanized caving working face to a belt conveyor; Step S440: Use a belt conveyor to transport the coal from the exit of the fully mechanized caving working face to the ground, and coal mining is completed.

[0065] The beneficial effect of the above optional embodiments is that through the coordinated arrangement of the coal mining machine, scraper conveyor, hydraulic support, transfer machine and belt conveyor, the coal can be smoothly taken and transported to the outside to ensure that the subsequent coal mining work is carried out quickly and smoothly.

[0066] Optional, such as Figures 1 to 3 As shown, a working surface support 5 is arranged in the cutting eye 9.

[0067] In the above optional embodiment, it should be noted that after step S100, after the multiple non-directional short holes 8 are opened, the working face support 5 is installed in the cutting eye 9, and then step 200 is performed to use a directional long drilling rig to open multiple directional holes along the side wall of the slot 7 in the direction of the cutting eye 9 towards the rock slab and rock layer 2, and the multiple directional holes are arranged in a triangle or rectangle.

[0068] The working face support 5 adopts the existing eye-cutting working face support, which mainly includes structures such as legs, beams, straight beams and pillars. Specifically, the legs are usually composed of straight sections and curved arc sections, and are divided into left legs, removable legs, right legs, etc. The legs are used to support both sides of the eye-cutting working face to ensure the stability of the working face; the straight and arc section designs of the legs help to better adapt to the shape and thickness of the coal seam and improve the support effect.

[0069] The canopy beam is composed of straight sections and curved arc sections, and is divided into left canopy beam, removable canopy beam, right canopy beam, etc. The canopy beam is used to support the top of the cut-eye working surface to prevent the roof from collapsing; the straight and curved sections of the canopy beam are designed to fit closely to the roof and provide effective support.

[0070] The straight beams include left and right straight beams, which are used to connect the shed legs and shed beams to form a stable support structure. The straight beams have a certain length and strength to ensure the stability and bearing capacity of the support structure.

[0071] The pillars are used to support the shed beams and straight beams, transfer the support force to the coal seam floor, and ensure the stability of the entire support structure; they mainly use single hydraulic pillars, which have the advantages of good support performance, uniform force, high initial support force, and small roof subsidence.

[0072] The beneficial effect of the above optional embodiment is that the stability of the top plate of the cutting eye 9 can be ensured by setting the working surface support 5, thereby ensuring safety.

[0073] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face, characterized in that: The following steps are involved: Step S100: using a non-directional drilling machine to drill a plurality of non-directional short holes (8) along the inner wall of the cut hole (9) toward the top coal seam (1); Step S200: using a directional long drilling rig to drill a plurality of directional holes along the side wall of the trench (7) in the direction of the cut hole (9) towards the rock slab and rock layer (2), wherein the plurality of directional holes are arranged in a triangular or rectangular shape; Step S300: performing directional jet fracturing on a plurality of directional holes to form at least three directional fractures, wherein the at least three directional fractures are connected clockwise and arranged in a polygonal form to form a rock block (6); Step S400: Push mining is carried out in the fully mechanized caving working face, and coal mining is completed.

2. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: In step S100, the distance between two adjacent non-directional short holes (8) is 8 meters to 12 meters.

3. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: In step S200, there are three directional holes, and the three directional holes are arranged in a triangle.

4. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: In step S300, the length of the rock block (6) is between 45 meters and 55 meters, and the thickness of the rock block (6) is between 24 meters and 26 meters.

5. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to any one of claims 1 to 4, characterized in that: Before step S100, a cut is made on the solid coal (9) to obtain a fully mechanized caving working face, in which a non-directional drilling rig and fully mechanized mining equipment are arranged.

6. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: The plurality of non-directional short holes (8) are arranged along the fully mechanized caving working face in a straight line or in a rectangular array or a circular array.

7. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: The depth of each of the directional holes is greater than the distance between the non-directional short holes (8) located at the head end and the non-directional short holes (8) located at the tail end in the plurality of non-directional short holes.

8. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 5, characterized in that: The comprehensive mining equipment includes a coal mining machine, a scraper conveyor, a hydraulic support, a transfer machine and a belt conveyor.

9. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 8, characterized in that: In step S400, the method for promoting acquisition includes the following steps: Step S410: using the coal mining machine to break and load coal; Step S420: using the scraper conveyor to transport the coal taken by the coal mining machine to the exit of the fully mechanized caving working face; Step S430: using the transfer machine to transfer the coal at the exit of the fully mechanized caving working face to the belt conveyor; Step S440: Use the belt conveyor to transport the coal from the exit of the fully mechanized caving working face to the ground, and the coal mining is completed.

10. The top coal roof fracturing method for improving the top coal recovery rate during the initial mining of the working face according to claim 1, characterized in that: A working surface support (5) is arranged in the cutting eye (9).

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