Mining method and mining equipment for corner coal pillars in mining area

Abstract

The invention discloses a mining area corner coal pillar mining method and mining equipment thereof, and relates to the technical field of lignite mining. The supporting problem is solved. The method specifically comprises the following steps that geological exploration and mining areas are delimited, and the geometrical morphology of corner coal pillars, the coal seam thickness and the lithology of a top plate and a bottom plate are determined by combining three-dimensional seismic exploration with a drilling peeping technology; an area with the coal pillar width larger than or equal to 8 m and the dip angle smaller than 25 degrees serves as a mineable area; two parallel roadways are constructed in the coal pillar trend, and a gob-side entry retaining technology is adopted to reserve a mining side roadway as a next subsection channel. On the basis of adopting multi-section mining, the hydraulic support and the gangue paste are adopted for synchronous filling during mining, so that the stability of the whole mining area is improved, in addition, the gangue paste is formed by mixing coal gangue, cement and fly ash in a fixed proportion, the bearing capacity can be increased on the basis of achieving quick drying, and the mining efficiency is improved. And the stability of the mining area is further improved, and collapse is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of lignite mining, and particularly relates to a mining method and mining equipment for corner coal pillars in a mining area. Background Art

[0002] Lignite, also known as firewood coal, is the lowest rank of mineral coal. A coal pillar is a part of coal mine mining. It is the part that is left unmined during coal mining for safety reasons. It is an important criterion for measuring the mining rate of a mining area.

[0003] After retrieval, the patent with the Chinese patent publication number CN11030698309 discloses a mining method for the corner coal pillar working face in a mining area. The mining method is as follows: Step 1: Leave a 5-10 m protective coal pillar between the working face material roadway, the transportation roadway and the old roadway, minimize the density between the roadways as much as possible, reduce the mutual disturbance between the roadways, and only arrange the material connection roadway, the transportation roadway connection roadway and the return air connection roadway in the working face; Step 2: Leave a 10-20 m protective coal pillar between the cutting eye and the old roadway, and minimize the length of the roadway rock roadway, the roadway slope and the transportation links.

[0004] The above patent has the following deficiencies: It cannot perform dynamic support on the corners of the mining area during the mining process. Since the coal pillar has a certain bearing effect on the entire mining area, there is a risk of collapse in the mining area when dynamic support is not carried out.

[0005] Therefore, the present invention proposes a mining method and mining equipment for corner coal pillars in a mining area. Summary of the Invention

[0006] The purpose of the present invention is to solve the defects existing in the prior art, and propose a mining method and mining equipment for corner coal pillars in a mining area.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions: A mining method for corner coal pillars in a mining area includes the following steps: S1: Geological exploration and delimitation of the mining area. Using three-dimensional seismic exploration combined with borehole peephole technology, determine the geometric shape, coal seam thickness and roof and floor lithology of the corner coal pillar; Take the area where the coal pillar width ≥ 8 m and the dip angle < 25° as the minable area; S2: Roadway layout: Construct two parallel roadways along the trend of the coal pillar, the roadway spacing is 15-18 m, and adopt the gob-side entry retaining technology to retain the roadway on the mining side as the next section passage; S3: Advance pre-splitting and support. Implement directional blasting 24 hours before mining, the hole spacing is 0.8 m, the charge amount is 1.2 kg / m, and form a pre-crack depth ≥ 3 m; Adopt the combined support of high-strength bolts + metal mesh + W-steel strip + cable bolts; S4: Sub - sectional mining. The coal pillar is divided into sections of 30 - 40 m along the strike. In each section, cyclic advancement is carried out at a footage of 2.0 - 2.5 m. A shearer is used for mining, with a cutting depth of 600 mm, and the mining height is controlled at 95% of the coal seam thickness. S5: Synchronous filling. Immediately after mining, gangue - paste filling is adopted. The strength of the filling body is ≥8 MPa. The filling pipeline extends from behind the hydraulic support. The filling rate is ≥20 m³ / h, and the roof - contact rate is >90%.

[0008] Preferably: In the step S3, the high - strength bolt has a size of Φ22×2400 mm; the metal mesh is woven with 8# iron wire, the W - steel strip has a size of 280×5 mm, and the cable bolt has a size of Φ21.6×8300 mm.

[0009] Furthermore: In the step S5, the mass ratio of the components of the gangue - paste is: gangue: cement: fly ash = 75:15:10.

[0010] A mining equipment for the corner coal pillar in a mining area includes a hydraulic mining vehicle and a crushing part connected to the hydraulic mining vehicle through a connecting frame. The crushing part includes a cavity matrix fixed to the inner side of the end of the connecting frame and a plurality of crushing units rotatably connected to the outer wall of the cavity matrix. The crushing units are linearly and closely arranged. Oblique tooth surfaces are provided on both inner sides of the crushing units. The oblique tooth surfaces of two adjacent crushing units are engaged with the same bevel gear. The bevel gear is rotatably connected to the radial direction of the cavity matrix through a connecting shaft. A hydraulic motor is fixed to the inner wall of the cavity matrix. The output shaft of the hydraulic motor is fixedly connected with a main shaft. The other end of the main shaft is in transmission cooperation with the outer wall of one of the connecting shafts through a transmission component. The oil inlet and outlet ends of the hydraulic motor are respectively connected with an oil pump and an oil tank through a two - position self - control valve.

[0011] A better solution in the above - mentioned scheme is: The crushing unit is composed of a plurality of base rings that are circularly arrayed and form a complete circular ring shape. The outer wall of the base ring is provided with crushing teeth. Dovetail grooves are opened at both ends of the base ring. Double - headed wedges are arranged on the inner walls of two mutually cooperating dovetail grooves. Both sides of the double - headed wedge are respectively fixed to the inner wall of the base ring through a screw.

[0012] As a further scheme of the present invention: The two - position self - control valve includes a housing fixed to the outer wall of the hydraulic motor and a valve core rotatably connected to the inner wall of the housing through a rotating shaft. Two symmetrically arranged out - mouths 1 are provided on the circumferential surface of the housing. Two symmetrically arranged in - mouths 1 are provided on the side surface of the housing. Two symmetrically arranged sector - shaped cavities are provided inside the valve core. Two groups of out - mouths 2 that cooperate with the out - mouths 1 are provided on the radial side wall of the valve core. Each group of out - mouths 2 is arranged in two. And the two out - mouths 2 in each group communicate with the same sector - shaped cavity. Two in - mouths 2 that are respectively communicated with the two sector - shaped cavities and respectively cooperate with the two in - mouths 1 are provided on the side surface of the valve core.

[0013] Meanwhile, two symmetrical cylinders are fixed on the side wall of the housing. A piston is slidably fitted inside the cylinder wall of each cylinder. The opposite sides of the two pistons are fixed to the same rack. One side of the rack meshes with a cylindrical gear, and the cylindrical gear is fixed to the outer wall of the rotating shaft.

[0014] As a preferred embodiment of the present invention: Two symmetrical cylinders are fixed on the side wall of the housing. A piston is slidably fitted inside the cylinder wall of each cylinder. The opposite sides of the two pistons are fixed to the same rack. One side of the rack meshes with a cylindrical gear, and the cylindrical gear is fixed to the outer wall of the rotating shaft.

[0015] Meanwhile, two sets of limiting grooves are formed on the side wall of the rack, and an elastic arc piece cooperating with one of the limiting grooves is fixed on the side wall of the housing.

[0016] As a more optimal solution of the present invention: Nozzles communicating with the inner cavity of the cylinder are provided at the ends of the cylinders, and the two nozzles are respectively connected to two first inlets through pipelines.

[0017] The beneficial effects of the present invention are as follows: 1. In the present invention, on the basis of adopting multi-stage mining, during mining, a hydraulic support and gangue gypsum body are synchronously filled, thereby increasing the stability of the entire mining area. In addition, the gangue gypsum body is a fixed proportion mixture of gangue, cement, and fly ash, which can achieve quick drying and also increase the bearing capacity, further increasing the stability of the mining area and preventing collapse.

[0018] 2. In the present invention, the entire crushing part is composed of multiple rotating crushing units, and by using the transmission of bevel gears, on the basis of using a common hydraulic motor as the power source, adjacent ones rotate in opposite directions, so that the reaction forces received by different crushing units are in opposite directions and balance and cancel each other, thereby reducing the mining load of the connecting frame and the hydraulic mining vehicle, achieving a certain energy-saving effect and also increasing the service life of each component.

[0019] 3. In the present invention, the crushing unit is set to be composed of multiple base rings. On the one hand, it is convenient for the installation and disassembly of the entire crushing unit relative to the cavity base body. On the other hand, when a single base ring or crushing tooth is damaged, it can also be replaced and repaired in a smaller block, without replacing the whole, reducing the use cost.

[0020] 4. In the present invention, by setting a two-position self-control valve, the speed switching of the hydraulic motor can be realized by using the two-position self-control valve, so that when in a stuck state, the stuck situation can be escaped by using speed switching. In addition, by setting components such as nozzles and cylinders, taking the oil pressure change during sticking as the induction, using the oil pressure difference as the drive, and combining with the dual channels of the two-position self-control valve, the full-automatic switching and escape function of self-induction, self-control, and self-drive can be achieved according to the oil pressure. Description of the Drawings

[0021] Figure 1 Schematic flow chart of a method for mining corner coal pillars in a mining area proposed by the present invention; Figure 2 Schematic diagram of the overall structure of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 3 Schematic diagram of the structure of the crushing part of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 4 For a mining equipment for corner coal pillars in a mining area proposed by the present invention Figure 3 Enlarged schematic diagram of part A; Figure 5 Schematic diagram of the structure of the crushing unit of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 6 For a mining equipment for corner coal pillars in a mining area proposed by the present invention Figure 5 Enlarged schematic diagram of part B; Figure 7 Schematic diagram of the separated structure of the two-position self-control valve of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 8 Schematic sectional view of the two-position self-control valve of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 9 Schematic diagram of one side of the two-position self-control valve of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 10 Schematic sectional view of the limit groove and elastic arc piece of a mining equipment for corner coal pillars in a mining area proposed by the present invention; Figure 11 Schematic diagram of the hydraulic pipeline structure of a mining equipment for corner coal pillars in a mining area proposed by the present invention.

[0022] In the figure: 1, connecting frame; 2, crushing part; 3, cavity matrix; 4, hydraulic motor; 5, two-position self-control valve; 6, main shaft; 7, transmission component; 8, connecting shaft; 9, crushing unit; 10, bevel gear; 11, crushing tooth; 12, base ring; 13, double-headed wedge block; 14, dovetail groove; 15, screw; 16, outer shell; 17, nozzle one; 18, inlet nozzle one; 19, nozzle two; 20, valve core; 21, sealing ring; 22, inlet nozzle two; 23, fan-shaped cavity; 24, rack; 25, piston; 26, oil nozzle; 27, cylinder block; 28, cylindrical gear; 29, rotating shaft; 30, limit groove; 31, elastic arc piece; 32, oil pump; 33, fuel tank. Detailed implementation manners

[0023] The technical solutions of the present invention will be further described in detail below in combination with the specific implementation manners.

[0024] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0025] Embodiment 1: A method for mining corner coal pillars in a mining area, which includes the following steps: S1: Geological exploration and determination of the mining area. Using three-dimensional seismic exploration combined with borehole peephole technology, determine the geometric shape, coal seam thickness, and roof and floor lithology of the corner coal pillar; take the area where the coal pillar width ≥ 8m and the dip angle < 25° as the minable area; S2: Roadway layout: Construct two parallel roadways along the strike of the coal pillar, with a roadway spacing of 15 - 18m. Adopt the gob-side entry retaining technology to retain the roadway on the mining side as the next section passage; S3: Advance pre-splitting and support. Implement directional blasting 24 hours before mining, with a borehole spacing of 0.8m and a charge amount of 1.2kg / m to form a pre-crack depth ≥ 3m; adopt a combined support of high-strength bolts + wire mesh + W-steel strip + cable bolts; S4: Sectional mining. Divide the coal pillar into sections of 30 - 40m along the strike, and advance in a cycle with a footage of 2.0 - 2.5m in each section. Use a shearer for mining, with a cutting depth of 600mm, and control the mining height within 95% of the coal seam thickness; S5: Synchronous filling. Immediately after mining, use gangue-cement paste for filling, with the filling body strength ≥ 8MPa. The filling pipeline extends from behind the hydraulic support, with a filling rate ≥ 20m³ / h and a roof contact rate > 90%.

[0026] In the step S3, the size of the high-strength bolt is Φ22×2400mm; the wire mesh is woven with 8# iron wire, the size of the W-steel strip is 280×5mm, and the size of the cable bolt is Φ21.6×8300mm.

[0027] In the step S5, the mass ratio of the components of the gangue-cement paste is: gangue: cement: fly ash = 75:15:10.

[0028] In the present invention, on the basis of adopting multi-section mining, during mining, hydraulic supports and gangue-cement paste are used for synchronous filling, thereby increasing the stability of the entire mining area. In addition, the gangue-cement paste is a fixed proportion mixture of gangue, cement, and fly ash, which can achieve quick drying and also increase the bearing capacity, further increasing the stability of the mining area and preventing collapse.

[0029] Embodiment 2: A mining equipment for corner coal pillars in a mining area, such as Figures 2 - 11As shown in the figure, to solve the mining problem; based on Embodiment 1, the following improvements are made to the shearer in step S4 of Embodiment 1: It includes a hydraulic mining vehicle and a crushing part 2 connected to the hydraulic mining vehicle through a connecting frame 1. In this embodiment, the hydraulic mining vehicle is not limited. The hydraulic mining vehicle has functions of walking, hydraulically controlling the lifting and angle transformation of the connecting frame 1. It is a prior art and is widely used in coal mine mining and roadheaders. No creative work has been done on it in this embodiment, so it will not be elaborated.

[0030] The crushing part 2 includes a cavity base body 3 fixed to the inner side of the end of the connecting frame 1 and a plurality of crushing units 9 rotatably connected to the outer wall of the cavity base body 3. The crushing units 9 are linearly and closely arranged.

[0031] On both inner sides of the crushing unit 9, there are bevel gear surfaces. The bevel gear surfaces of two adjacent crushing units 9 are meshed with the same bevel gear 10. The bevel gear 10 is rotatably connected to the radial direction of the cavity base body 3 through a connecting shaft 8. And a hydraulic motor 4 is fixed to the inner wall of the cavity base body 3. The output shaft of the hydraulic motor 4 is fixedly connected with a main shaft 6. The other end of the main shaft 6 is in transmission cooperation with the outer wall of one of the connecting shafts 8 through a transmission component 7. The oil inlet and outlet ends of the hydraulic motor 4 are respectively connected with an oil pump 32 and an oil tank 33 through a two-position self-control valve 5.

[0032] When this device is in use, the oil pump 32 pumps out the oil in the oil tank 33 and inputs it into the hydraulic motor 4 through the two-position self-control valve 5. After the oil drives the hydraulic motor 4 to rotate, it then flows back into the oil tank 33 through the two-position self-control valve 5. The rotation of the hydraulic motor 4 drives the connecting shaft 8 to rotate through the main shaft 6 and the transmission component 7. Thus, the crushing unit 9 is driven to rotate through the bevel gear 10. And the rotation directions of adjacent crushing units 9 are opposite. At this time, through the movement of the hydraulic mining vehicle and the adjustment of the angular position of the multi-connecting frame 1 and the crushing part 2, mining can be carried out.

[0033] Since when the crushing unit 9 rotates to crush and mine the corner coal pillar, the crushing unit 9 will also be subjected to the reaction force of the coal pillar. The reaction force will be transmitted to the hydraulic mining vehicle through the connecting frame 1. In this device, the entire crushing part 2 is composed of a plurality of rotating crushing units 9. And by using the transmission of the bevel gear 10, on the basis of using the common hydraulic motor 4 as the power source, adjacent ones rotate in opposite directions. Thus, the reaction forces received by different crushing units 9 are in opposite directions and balance and offset each other. Thereby reducing the mining load of the connecting frame 1 and the hydraulic mining vehicle, which can achieve a certain energy-saving effect and also increase the service life of each component.

[0034] For the convenience of installation and disassembly problems, such as Figure 5 、 6As shown, the crushing unit 9 is composed of a plurality of base rings 12 arranged in a circular array to form a complete ring shape. The outer wall of the base ring 12 is provided with crushing teeth 11. Dovetail grooves 14 are opened at both ends of the base ring 12. A double-headed wedge block 13 is arranged on the inner walls of two mutually cooperating dovetail grooves 14. Both sides of the double-headed wedge block 13 are fixed to the inner wall of the base ring 12 by a screw 15 respectively.

[0035] In this device, by setting the crushing unit 9 as a composition of a plurality of base rings 12, on the one hand, it is convenient for the installation and disassembly of the entire crushing unit 9 relative to the cavity base body 3. On the other hand, when a single base ring 12 or crushing tooth 11 is damaged, it can also be replaced and repaired in a smaller block, without the need for overall replacement, reducing the use cost.

[0036] To solve the jamming problem, as Figures 7 - 11 shown, the two-position self-control valve 5 includes a housing 16 fixed to the outer wall of the hydraulic motor 4 and a valve core 20 rotatably connected to the inner wall of the housing 16 through a rotating shaft 29. Two symmetrically arranged outlet nozzles one 17 are provided on the circumferential surface of the housing 16. Two symmetrically arranged inlet nozzles one 18 are provided on the side surface of the housing 16. Two symmetrically arranged sector cavities 23 are provided inside the valve core 20. Two groups of outlet nozzles two 19 are arranged on the radial side wall of the valve core 20 to cooperate with the outlet nozzles one 17. Each group of outlet nozzles two 19 is arranged in two, and the two outlet nozzles two 19 in each group communicate with the same sector cavity 23. Two inlet nozzles two 22 that are respectively communicated with the two sector cavities 23 and respectively cooperate with the two inlet nozzles one 18 are provided on the side surface of the valve core 20.

[0037] Sealing rings 21 for sealing are fixedly embedded on the inner walls of the valve core 20 at the positions of the outlet nozzles two 19 and the inlet nozzles two 22.

[0038] Two symmetrically arranged cylinders 27 are fixed to the side wall of the housing 16. A piston 25 is slidably fitted inside the cylinder 27. The opposite sides of the two pistons 25 are fixed to the same rack 24. One side of the rack 24 meshes with a cylindrical gear 28, and the cylindrical gear 28 is fixed to the outer wall of the rotating shaft 29.

[0039] Two groups of limiting grooves 30 are opened on the side wall of the rack 24. An elastic arc piece 31 that cooperates with one of the limiting grooves 30 is fixed to the side wall of the housing 16.

[0040] Nozzles 26 communicating with the inner cavity of the cylinder 27 are provided at the ends of the cylinder 27. The two nozzles 26 are respectively connected to the two inlet nozzles one 18 through pipelines.

[0041] During normal use, the oil pump 32 inputs the oil fluid into an oil port of the hydraulic motor 4 through one of the inlet nozzles 18, inlet nozzle 22, sector cavity 23, outlet nozzle 19, and outlet nozzle 17, and then returns it to the fuel tank 33 through the other group. The oil pressures of the two are transmitted to the cylinder block 27 through the inlet nozzle 18 and the oil nozzle 26. The piston 25 is subjected to the oil pressure force. However, at this time, due to normal operation, the oil pressures at the inlet and outlet of the hydraulic motor 4 are normal, and the pressure difference received by the two pistons 25 is not sufficient to overcome the movement resistance of the rack 24 by the cooperation of the elastic arc plate 31 and the limit groove 30. The rack 24 does not move, maintaining the normal mining state. When the crushing unit 9 gets stuck, the oil pressure at the inlet of the hydraulic motor 4 will abnormally increase at this time, so that the oil pressure in the cylinder block 27 connected to the inlet increases. The force received by the piston 25 here increases, increasing the force difference between the two pistons 25, so that the rack 24 overcomes the cooperation resistance of the limit groove 30 and the elastic arc plate 31 and moves. The rack 24 drives the rotating shaft 29 to rotate through the cylindrical gear 28, so that the valve core 20 rotates relative to the housing 16. At this time, the connection relationship between the two outlet nozzles 17 and the two sector cavities 23 will cross due to the rotation of the outlet nozzle 19, while the connection relationship between the two inlet nozzles 18 and the two sector cavities 23 remains unchanged, so that the oil inlet and outlet of the hydraulic motor 4 are switched. The hydraulic motor 4 will be reversely rotated relative to the stuck state, so as to drive the crushing unit 9 to rotate reversely. If the reverse rotation gets stuck again, the oil pressure will be switched to the forward rotation again.

[0042] In this device, by setting the two-position automatic control valve 5, the rotation speed of the hydraulic motor 4 can be switched by using the two-position automatic control valve 5, so that the device can get out of trouble by using the rotation speed switch in the stuck state. In addition, by setting components such as the oil nozzle 26 and the cylinder block 27, which use the oil pressure change during sticking as the induction, use the oil pressure difference as the drive, and combine with the double-channel of the two-position automatic control valve 5, the device can achieve the fully automatic switching and trouble-getting-out function of self-induction, self-control, and self-drive according to the oil pressure.

[0043] During the use of this embodiment, the oil pump 32 pumps out the oil in the fuel tank 33 and inputs it into the hydraulic motor 4 through the two-position self-control valve 5. After the oil drives the hydraulic motor 4 to rotate, it then returns to the fuel tank 33 through the two-position self-control valve 5. The rotation of the hydraulic motor 4 drives the connecting shaft 8 to rotate through the main shaft 6 and the transmission assembly 7, thereby driving the crushing unit 9 to rotate through the bevel gear 10. And the adjacent crushing units 9 rotate in opposite directions. At this time, through the movement of the hydraulic mining vehicle and the adjustment of the angular position of the multi-connecting frame 1 and the crushing part 2, mining can be carried out. During normal use, the oil pump 32 inputs the oil into an oil port of the hydraulic motor 4 through one of the inlet nozzles 18, inlet nozzle 22, fan-shaped cavity 23, outlet nozzle 19, and outlet nozzle 17, and then returns to the fuel tank 33 from the other group. The oil pressures of the two are transmitted to the cylinder block 27 through the inlet nozzle 18 and the oil nozzle 26. The piston 25 is subjected to the oil pressure force. However, at this time, due to normal operation, the oil pressures at the inlet and outlet of the hydraulic motor 4 are normal, and the pressure difference received by the two pistons 25 is not sufficient to overcome the movement resistance of the rack 24 by the cooperation of the elastic arc piece 31 and the limit groove 30. The rack 24 does not move, maintaining the normal mining state. When the crushing unit 9 becomes stuck, at this time, the oil pressure at the inlet of the hydraulic motor 4 will abnormally increase, so that the oil pressure in the cylinder block 27 connected to the inlet increases. The force received by the piston 25 here increases, increasing the force difference between the two pistons 25, so that the rack 24 overcomes the cooperation resistance of the limit groove 30 and the elastic arc piece 31 and moves. The rack 24 drives the rotating shaft 29 to rotate through the cylindrical gear 28, so that the valve core 20 rotates relative to the housing 16. At this time, the connection relationship between the two outlet nozzles 17 and the two fan-shaped cavities 23 will cross due to the rotation of the outlet nozzle 19, while the connection relationship between the two inlet nozzles 18 and the two fan-shaped cavities 23 remains unchanged, so that the inlet and outlet ports of the hydraulic motor 4 are switched. The hydraulic motor 4 will be reversely rotated relative to the stuck state, thereby driving the crushing unit 9 to rotate in the reverse direction. If the reverse rotation becomes stuck again, the oil pressure will be switched to the forward rotation again.

[0044] 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 person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for mining coal pillars at the corners of a mining area, characterized in that: The following steps are involved: S1: Geological exploration and mining area delineation, using 3D seismic exploration combined with drilling peek technology to determine the geometric shape of the corner coal pillars, coal seam thickness and roof and floor lithology; the area with a coal pillar width of ≥8m and a dip angle of <25° is considered as the mineable area; S2: Tunnel layout: Two parallel tunnels are constructed along the direction of the coal pillar, with a tunnel spacing of 15-18m. The side tunnel of the mining side is retained as the next segment channel using the gob-side tunnel retention technology; S3: Pre-crack and support: directional blasting is carried out 24 hours before mining, with a drilling spacing of 0.8m and a charge of 1.2kg / m, to form a pre-crack depth of ≥3m; high-strength anchor rod + metal mesh + W steel belt + anchor cable combined support is adopted; S4: Segmented mining, the coal pillar is divided into 30-40m segments along the strike, and each segment is advanced cyclically at a 2.0-2.5m advance. Coal mining is carried out by coal mining machine, with a cutting depth of 600mm and a mining height controlled at 95% of the coal seam thickness; S5: Synchronous filling: Gangue paste is used for filling immediately after mining. The filling strength is ≥8MPa. The filling pipeline extends behind the hydraulic support. The filling rate is ≥20m³ / h and the top connection rate is >90%.

2. A method for mining corner coal pillars in a mining area according to claim 1, characterized in that: In the step S3, the size of the high-strength anchor rod is Φ22×2400mm; the metal mesh is woven with 8# iron wire, the size of the W steel belt is 280×5mm, and the size of the anchor cable is Φ21.6×8300mm.

3. A method for mining corner coal pillars in a mining area according to claim 1, characterized in that: In the step S5, the mass ratio of the components of the gangue slurry is: gangue: cement: fly ash = 75:15:

10.

4. A mining equipment for mining corner coal pillars, which is a coal mining machine used in step S4 of the mining method for mining corner coal pillars according to any one of claims 1 to 3, characterized in that: The invention comprises a hydraulic mining vehicle and a crushing part (2) connected to the hydraulic mining vehicle via a connecting frame (1), wherein the crushing part (2) comprises a cavity base (3) fixed to the inner side of the end of the connecting frame (1) and a plurality of crushing units (9) rotatably connected to the outer wall of the cavity base (3), wherein the crushing units (9) are linearly and closely arranged, and the inner sides of both sides of the crushing units (9) are provided with helical tooth surfaces, and the helical tooth surfaces of two adjacent crushing units (9) are meshed with the same bevel gear (10), and the bevel gear (10) is rotatably connected to the radial direction of the cavity base (3) via a connecting shaft (8), and a hydraulic motor (4) is fixed to the inner wall of the cavity base (3), and the output shaft of the hydraulic motor (4) is fixedly connected to a main shaft (6), and the other end of the main shaft (6) is transmission-matched to the outer wall of one of the connecting shafts (8) via a transmission assembly (7), and the oil input and output ends of the hydraulic motor (4) are respectively connected to an oil pump (32) and an oil tank (33) via a two-position automatic control valve (5).

5. The mining equipment for corner coal pillars according to claim 4 is characterized in that: The crushing unit (9) is composed of a plurality of base rings (12) arranged in a circular array to form a complete circular ring shape. The outer wall of the base ring (12) is provided with crushing teeth (11). Dovetail grooves (14) are provided at both ends of the base ring (12). Double-headed wedge blocks (13) are provided on the inner walls of the two mutually matching dovetail grooves (14). The two sides of the double-headed wedge block (13) are respectively fixed to the inner wall of the base ring (12) by a screw (15).

6. The mining equipment for corner coal pillars according to claim 4 is characterized in that: The two-position automatic control valve (5) comprises a housing (16) fixed to the outer wall of a hydraulic motor (4) and a valve core (20) rotatably connected to the inner wall of the housing (16) via a rotating shaft (29); the circumferential surface of the housing (16) is provided with two symmetrical outlet nozzles (17); the side surface of the housing (16) is provided with two symmetrical inlet nozzles (18); the interior of the valve core (20) is provided with two symmetrical fan-shaped cavities (23); the radial side wall of the valve core (20) is provided with two groups of outlet nozzles (19) matched with the outlet nozzles (17); each group of outlet nozzles (19) is arranged in two, and the two outlet nozzles (19) in each group are connected to the same fan-shaped cavity (23); the side surface of the valve core (20) is provided with two inlet nozzles (22) respectively connected to the two fan-shaped cavities (23) and respectively matched with the two inlet nozzles (18).

7. The mining equipment for corner coal pillars according to claim 6 is characterized in that: Two symmetrical cylinder bodies (27) are fixed to the side wall of the housing (16); a piston (25) is slidably fitted on the inner wall of the cylinder body (27); a same rack (24) is fixed to the opposite side of the two pistons (25); a cylindrical gear (28) is meshed with one side of the rack (24); and the cylindrical gear (28) is fixed to the outer wall of the rotating shaft (29).

8. The mining equipment for corner coal pillars according to claim 6 is characterized in that: Two symmetrical cylinder bodies (27) are fixed to the side wall of the housing (16); a piston (25) is slidably fitted on the inner wall of the cylinder body (27); a same rack (24) is fixed to the opposite side of the two pistons (25); a cylindrical gear (28) is meshed with one side of the rack (24); and the cylindrical gear (28) is fixed to the outer wall of the rotating shaft (29).

9. The mining equipment for corner coal pillars according to claim 8, characterized in that: Two groups of limiting grooves (30) are formed on the side wall of the rack (24), and an elastic arc piece (31) matched with one of the limiting grooves (30) is fixed on the side wall of the housing (16).

10. The mining equipment for corner coal pillars according to claim 9, characterized in that: An oil nozzle (26) communicating with the inner cavity of the cylinder (27) is provided at the end of the cylinder (27), and the two oil nozzles (26) are respectively connected to the two inlet nozzles (18) through pipelines.

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