Pseudo-inclined mining process for steeply inclined coal seam

Abstract

The invention relates to a pseudo-inclined down mining process for a steeply inclined coal seam, which adopts a stoping method, a coal face is arranged between a return airway and a machine roadway, a coal mining machine is arranged on the coal face to walk and cut coal, and a support facility is arranged on the coal face. And when the true dip angle of the coal seam is more than 70 degrees and the average inclination length is more than 100 meters, the outlet on the coal face arranged in the coal seam is 15-20 mm ahead of the lower outlet, so that the false dip angle of the coal face is 58-62 degrees. Due to the fact that the coal face is inclined at the pseudo-inclined angle, flying waste rocks and channeling waste rocks are not prone to entering an operation area, the impact force of flying waste rocks and channeling waste rocks is reduced, the safety threat of flying waste rocks and channeling waste rocks to operators is reduced, and the stoping efficiency and the safety effect of the coal face are improved.

Description

Technical Field

[0001] The invention relates to an underground coal mining method, in particular to a steeply inclined coal seam downward-sloping mining process. Background Art

[0002] The reserves of steeply inclined coal seams account for 40% of the total coal reserves in my country, and 80% of the southern mining areas have steeply inclined coal seams. So far, the mining methods of steeply inclined and extremely thin coal seams are mainly classified by support form: the first is the pseudo-inclined constant wall segmented intensive mining method, which adopts the method of blasting coal and single hydraulic support support. This method has extremely low production efficiency, poor safety guarantee, and high labor intensity for workers; the loss of segmented coal pillars is large, accounting for about 15% of the coal volume in the section; the "triangle area" below the dense segmented trend is poorly ventilated and easy to accumulate gas; the second is the flexible shield support mining method, which requires the coal seam to be relatively stable; the inclination angle is large; the labor intensity of disassembling and assembling the support is large; the support isolates the working space from the goaf, and the gangue cannot be removed during the mining process; the above-mentioned steeply inclined and extremely thin coal seam mining methods cannot achieve efficient mining, and safety cannot be fundamentally guaranteed. In order to achieve sustainable development of mines and make full use of coal resources, it is necessary to improve the pseudo-inclined mining process technology of steeply inclined coal seams. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a steeply inclined coal seam downward pseudo-inclined mining process.

[0004] The coal mining process of the present invention is to set a return air lane and a machine lane with a horizontal position lower than the return air lane in the coal seam, and adopt a return mining method, arrange a coal mining working face between the return air lane and the machine lane, arrange a coal mining machine on the coal mining working face to walk and cut coal, and set support facilities on the coal mining working face.

[0005] The coal mining face has an upper outlet close to the return air lane and a lower outlet close to the machine lane.

[0006] Specifically: when the true inclination of the coal seam is above 70° and the average inclination length is above 100 meters, the upper outlet of the coal mining face arranged in the coal seam is 15-20mm ahead of the lower outlet, so that the pseudo inclination of the coal mining face is 58°-62°.

[0007] In the above-mentioned steeply inclined coal seam downward pseudo-inclined mining process, the method of walking and cutting coal by arranging the coal mining machine on the coal mining working face is as follows: A feed section is provided at the upper outlet, and the feed section is arranged obliquely with the coal mining working face to form an angle of less than 8°; the coal mining machine gradually cuts into the coal wall when it moves, completing the feed; the first coal cutting is 0.8m; After the feed is completed, the coal is cut downward to the lower outlet, and the downward speed is not more than 3m / minute.

[0008] In the steeply inclined coal seam downward pseudo-inclined mining process as described above, the length of the feed section is 25m-30m.

[0009] In the steeply inclined coal seam downward pseudo-inclined mining process as described above, the support strength of the support facilities is greater than 280kN / m2.

[0010] The steeply inclined coal seam downward pseudo-inclined mining process as described above, wherein the support facilities include hydraulic supports with a support strength greater than 386kN / m2; the top plate of the hydraulic support is parallel to the top plate of the coal mining face, the center line of the hydraulic support is parallel to the return air lane and the machine lane, and the center line of the hydraulic support forms an angle of 78-72° with the coal mining face.

[0011] In the above-mentioned steeply inclined coal seam pseudo-inclined mining process, the hydraulic support is continuously advanced along the direction of the coal mining face with the mining, and the roof of the mining section is controlled, with the maximum roof control distance of 5.64m, the minimum roof control distance of 4.84m, and the roof caving step distance of 0.8m; The hydraulic support push conveyor pushes the hydraulic support at the lower end of the coal mining face first, and then gradually pushes the remaining hydraulic supports upwards during each coal mining cycle. The goaf area after the coal mining face is pushed through is treated by the full collapse method.

[0012] In the above-mentioned steeply inclined coal seam pseudo-inclined mining process, the length of the section without hydraulic support at the exit of the coal mining working face shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be added immediately; the length of the section without hydraulic support at the lower exit shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be lowered downward; The lower exit section without hydraulic props is supported by a single hydraulic prop with a cap, the row spacing of the single hydraulic prop is 0.8m, the column spacing is 0.8m, the top control distance is between 4.34m and 5.14m, and the top release step distance is 0.8m.

[0013] In the above-mentioned steeply inclined coal seam downward pseudo-inclined mining process, the pedestrian safety exit section at the lower exit is supported by a single hydraulic support with a wooden cantilever board, wherein the specification of the wooden cantilever board is: 200mm long, 100mm wide, and 50mm thick; Among them, the density of single hydraulic pillars is not less than 0.8 pillars / m2, the row spacing of single hydraulic pillars is 0.8m, and the pillar spacing is 0.8m.

[0014] In the steeply inclined coal seam pseudo-inclined mining process as described above, a row of inclined dense pillars are arranged close to the coal wall side of the pedestrian safety exit section at the lower exit, and the column spacing of the inclined dense pillars is 400mm; and a row of walking pillars are built in the pedestrian safety exit section at the lower exit near the top beam of the first support frame, and the column spacing is 400mm.

[0015] As described above, in the steeply inclined coal seam pseudo-inclined mining process, after the coal mining face is advanced, when withdrawing the support facilities, the walking pillars are withdrawn first, and then the inclined dense pillars are withdrawn, and the replacement pillars are set before withdrawing the inclined dense pillars.

[0016] Beneficial technical effects: After more than 7 months of verification mining, as the angle of the coal mining face slowed down and the inclination of the coal mining face was reduced, the verification mining coal mining face did not experience any frame collapse or sliding, and the operating risk of the operators was also reduced. Due to the angle of the coal mining face, flying gangue and gangue are not easy to enter the operating area, which reduces the impact of flying gangue and gangue, and reduces the safety threat of flying gangue and gangue to operators. Since the use of the forward pseudo-inclined mining method, the coal mining face has not had any injuries caused by flying gangue and gangue, which effectively ensures the safety of the operators and improves the recovery efficiency and safety effect of the coal mining face.

[0017] There has been a significant change in the difficulty of mining, the average monthly output has increased significantly, the equipment failure rate has been greatly reduced, and the safety effect is obvious. According to uncertain data statistics, since the coal mining face was adjusted to pseudo-inclined mining, the mine has reduced its investment by nearly 10 million yuan.

[0018] Through verification mining, multiple steeply inclined coal mining faces, including 0.6-0.8m thin coal seams and 1.15-1.45m medium-thick coal seams, were safely recovered, and each face exceeded the production task. Compared with the previous true-inclined and pseudo-inclined comprehensive mining, the per capita output of a single face increased by 25%, the ton of coal efficiency increased by 31%, the coal recovery rate increased by 25%, and no safety accidents such as flying gangue injuring people occurred in the steeply inclined coal mining faces.

[0019] By adjusting the inclination angle of the coal mining face and the support arrangement angle, the time for rectification of the coal mining face due to frame collapse, sliding frame, and coal cutter overturning is reduced, providing sufficient time for the coal mining face to be recovered and ensuring the advancement of the coal mining face. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the layout of the coal mining working face of the present invention.

[0021] Figure 2 It is a schematic diagram of the layout of the hydraulic support of the present invention, and a schematic diagram of the process of feeding and pushing the conveyor; Figure 2 (a) is the layout of hydraulic support; Figure 2 (b) is the curved section of the conveyor; Figure 2 (c) The coal mining machine enters the curved section of the conveyor; Figure 2 (d) The coal mining machine passes through the curved section of the conveyor; Figure 2 (e) The coal mining machine moves upward to complete the cutting. DETAILED DESCRIPTION

[0022] Example 1: The present invention can be arranged in the steeply inclined coal seams in the following situations, but is certainly not limited to being arranged in the following coal seams.

[0023] Basic information of the verification mining coal mining face: the average strike length of the coal mining face is 750m, the average inclined length is 120m, the average thickness of the coal seam is 1.45m, the coal seam inclination is more than 70°, and the average inclined area of ​​the coal seam is 99442m2. The coal mining face adopts the backward single strike longwall mining method, adopts comprehensive mechanized coal mining, and in order to improve the resource recovery rate, the machine tunnel is protected along the goaf and there is no coal pillar mining.

[0024] The machine tunnel is used for ventilation, pedestrians, coal transportation, material transportation and storage. The machine tunnel support method: the roof and the two sides are permanently supported by threaded steel resin anchor rods with T-shaped steel belts, anchor cables, and wire mesh (the roof coal part does not use T-shaped steel belts, only resin anchor rods with wire mesh), and the roof is reinforced with 5180mm long, Ф=17.8mm steel strand anchor cables (the resin anchor rods at the position close to the coal seam and the right side arch can be replaced when two rows of anchor rods are used for support). The roof anchor rods are supported by L=1800mm, φ=18mm threaded steel resin anchor rods. 300mm below the high side coal seam of the tunnel is supported by 3180mm long, Ф=17.8mm steel strand anchor cables, and flat iron steel belts are used to lock the side along the tunnel.

[0025] The return air duct is used for ventilation, pedestrians, materials and equipment transportation.

[0026] The shearer drum arranged at the coal mining face has a diameter of 1.4m, an adaptable mining height of 1.6-2.5m, a drum cutting depth of 0.8m, and a travel speed of 0-4.0m / min. The coal mining face uses the MG250 / 710-AWD3 spiral double-drum shearer to cut and drop coal, with a cutting depth of 0.8m.

[0027] The hydraulic support has a support height of 1.4-3.2m, a support width of 1.43-1.60m, an initial support force of 1538kN-2561kN, and a support strength of 0.38Mpa-0.47Mpa. The coal mining face uses the ZY3200 / 14 / 32Q steeply inclined shielding hydraulic support The coal mining face uses a scraper conveyor to transport coal to the machine tunnel Example 2: refer to Figure 1 , pseudo-inclination arrangement of coal mining working face.

[0028] The layer angle directly affects the self-flowing effect of coal. The natural repose angle of coal is generally 45°. The larger the angle, the more conducive it is to the self-flowing of coal. However, it also increases the efficiency of converting the potential energy of coal blocks into kinetic energy, causing the coal blocks to roll down too fast, causing damage to the equipment below the coal mining face, and flying into the working area will also pose a huge threat to personnel safety. If the coal seam inclination is too small, the self-flow speed will be slow, affecting the mining efficiency and coal recovery. If the inclination is too large, there will be safety hazards.

[0029] refer to Figure 1 In the figure, OC is a coal mining face with a pseudo-inclined layout, β=∠OBA is the true inclination angle of the inclined plane OBC of the steeply inclined coal seam, and βˊ=∠OCA is the pseudo inclination angle of the coal mining face. The relationship between the two is related to the plane angle δ.

[0030] In order to achieve the requirement of making the pseudo inclination angle βˊ of the coal mining face 58°-62° during coal seam mining, the formula is: sinβˊ=sinβ×sinδ calculation, It can be known that the plane angle is: Arranged at a layer angle of 78-72°, the pseudo-inclination angle βˊ of the coal mining face can be formed into 58°-62°. Through the ground model, it is found that when the pseudo-inclination angle of the coal mining face is 58°-62°, the distance of the return air lane ahead of the machine lane is 15m-20m, the layer angle is 78°-82°, and the pseudo-inclination angle of the coal mining face is reduced from 70° to about 58°-62°. The pseudo-inclination angle of the coal mining face has a significant slowdown, which enables the coal mining machine to overcome the phenomenon of overturning, and flying gangue and gangue are not easy to enter the working area. However, due to the excessively large angle of the pseudo-inclination angle of the coal mining face and the excessively large end face distance of the support, effective support must be established for the roof of the coal mining face, otherwise the roof is prone to collapse, causing the coal cutting channel to be blocked, and the collapsed gangue to damage the equipment.

[0031] Example 3: The coal mining process sequence is: coal cutting preparation, coal cutter goes down to cut coal, pushes hydraulic supports (hydraulic supports alternately approach the coal wall, while the conveyor does not move, which is equivalent to the hydraulic supports being pulled by the conveyor through the connection between the hydraulic supports and the conveyor), coal cutter goes up without load, collects floating coal, pushes the conveyor (equivalent to the hydraulic supports being pushed by the conveyor through the connection between the hydraulic supports and the conveyor), and cuts in. This is a coal mining cycle.

[0032] The coal mining machine is a spiral double-drum coal mining machine that cuts and drops coal downward.

[0033] The coal loading method is to use the spiral double drum of the coal mining machine in combination with the coal shoveling plate of the scraper conveyor.

[0034] The coal transportation method is that the coal mining face uses a bridge-type transfer machine to transport coal to the machine lane.

[0035] A feed section is set at the upper exit, and the coal mining machine adopts end oblique cutting feed. The length of the feed section is not less than 28m. The feed section is inclined with the coal mining working face to form an angle of less than 8°; the coal mining machine gradually cuts into the coal wall while moving to complete the feed; the first coal feed is 0.8m.

[0036] After the cutting is completed, the coal is cut downward to the lower exit, and the downward speed is no more than 3m / minute. After the coal cutting is completed, it returns to the empty position and the maximum upward speed of the coal mining machine is ≤2m / minute.

[0037] Determination of the length of the feed section: D = L mining + L transport bend = 13 + 15 = 28m Where: D—feed section length, m; L-mining - the coal mining machine has a long body, with a maximum length of 13m; L transport bend - the length of the conveyor bend section, take 15m; The cutting distance is 28m.

[0038] Example 4: Set up support facilities at the coal mining face.

[0039] The support strength of the support facilities is greater than 280kN / m2. In this example, 283kN / m2 is taken based on the following: Calculate the reasonable support strength of coal mining working face as follows: pt=9.81hγk=9.81×2.0×2.4×6≈283kN / m2 Where: Pt is the reasonable support strength of the coal mining face, kN / m2; h is the mining height, and the maximum mining height is 2.0 (m); γ is the gravity density of roof rock, 2.4t / m3; k is the ratio of the thickness of the overlying rock layer that the pillars of the coal mining face should support to the mining height, which is generally 4-8.

[0040] Under the above reasonable support strength requirements, according to the coal seam roof and floor conditions, coal seam conditions, and mining height conditions of the coal mining working face, the ZY3200 / 14 / 32Q hydraulic support is selected. The support strength of the support is calculated based on the working resistance of the hydraulic support of 3200kN: The minimum support strength of the support is 386kN / m2, which is greater than the compressive strength of the roof of the coal mining face of 283kN / m2.

[0041] Coal mining face roof control technology: The roof of the coal mining face is supported by a machine-pull frame, and the hydraulic support is continuously pushed forward along the direction of the coal mining face to control the roof of the mining section. The maximum top control distance is 5.64m, the minimum top control distance is 4.84m, and the top release step distance is 0.8m. The goaf after the coal mining face is pushed through is handled by the full collapse method.

[0042] refer to Figure 2 (a), the top plate or bottom plate of the hydraulic support 6 is a plane, the center line 61 of the hydraulic support is parallel to the length direction of the plane, and the coal mining face is arranged in the coal seam 1. After the hydraulic support is lowered to the coal mining face, the hydraulic support posture is adjusted so that the top plate of the hydraulic support is parallel to the top plate of the coal mining face, the center line of the hydraulic support is parallel to the return air lane 2 and the machine lane 3, and the center line of the hydraulic support forms an angle of 78-72° with the coal mining face. To this end, the coal mining machine 4 goes down to cut coal, and after the coal cutting is completed, it returns to empty and ascends, and collects floating coal when returning to empty and ascending (the cut coal is collected on the conveyor by rotating the drum 5), and the coal mining machine 4 goes up to the upper exit and collects all floating coal. Then, except for the multiple hydraulic supports at the upper exit, the rest of the hydraulic supports in the entire coal mining face began to push the conveyor 7 towards the coal wall, and the pushing direction was parallel to the return air lane and the machine lane (forming an angle of 78-72° with the coal mining face); since the multiple hydraulic supports at the upper exit had not yet pushed the conveyor 7, a 15m conveyor bending section was formed here, referring to Figure 2 (b); Then the coal mining machine goes down, and when it enters the curved section, the drum 5 cuts into the coal wall 8, and enters the conveyor section that has completed the push to the coal wall, reference Figure 2 (c), the roller goes deep into the coal wall 8; then the multiple hydraulic supports at the upper outlet start to push the conveyor closer to the coal wall, so that the conveyor of the entire coal mining face is parallel to the coal mining face (coal wall) and pulled into a straight line, reference Figure 2 (d) The coal mining machine goes up again and cuts off the coal at the upper outlet. Figure 2(e); Then, normal coal mining begins by descending. The center line 61 of the hydraulic support is parallel to the return air lane 2 and the machine lane 3. Therefore, when the hydraulic support is pushed, it will move along the direction of the return air lane and the machine lane, and the hydraulic support will not slide down (if the center line of the hydraulic support is perpendicular to the coal wall, then after each hydraulic support moves, it will move a distance closer to the lower outlet. Because the coal mining working face is inclined, it is necessary to continuously add supports from the upper outlet and remove supports from the lower outlet during the advancement of the coal mining working face), reducing or avoiding adding hydraulic supports from the upper outlet and removing hydraulic supports from the lower outlet, reducing workload and improving coal mining efficiency. This method also reduces or avoids adding conveyor sections from the upper outlet and removing conveyor sections from the lower outlet (because if the hydraulic support moves a distance closer to the lower outlet each time it moves, then the conveyor will also move a distance to the lower outlet). The pushing conveyor and the feeding method in this example effectively cooperate with the hydraulic support to move in a direction parallel to the return air lane and the machine lane. Among them, after the upward collection of floating coal is completed, the conveyor is pushed from bottom to top, and the sections of the conveyor will be squeezed upward (at least not downward), avoiding the conveyor from moving toward the downward exit. The conveyor has enough length to form a curved section (if the conveyor moves toward the downward exit, the length in the upper exit direction is insufficient, and the length required to form a curved section is insufficient). There is no need to lower the conveyor section to the coal mining face for the curved section, thereby reducing the workload.

[0043] The length of the section without hydraulic support at the exit of the coal mining working face shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be added immediately; the length of the section without hydraulic support at the lower exit shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be lowered.

[0044] The section without hydraulic supports at the lower exit is supported by a single hydraulic support with caps. The row spacing of the single hydraulic support is 0.8m, the column spacing is 0.8m, the top control distance is between 4.34m and 5.14m, and the top release step distance is 0.8m.

[0045] Support method of the lower outlet section without hydraulic support: The pedestrian safety exit sections at the upper and lower exits are supported by single hydraulic pillars with wooden cantilevers. The specifications of the wooden cantilevers are: 200mm long, 100mm wide and 50mm thick.

[0046] Among them, the density of single hydraulic pillars is not less than 0.8 pillars / m2, the row spacing of single hydraulic pillars is 0.8m, and the pillar spacing is 0.8m.

[0047] A row of inclined dense pillars are arranged close to the coal wall side of the pedestrian safety exit section at the lower exit, with a column spacing of 400mm; a row of walking pillars are built close to the top beam of the first support frame in the pedestrian safety exit section at the lower exit, with a column spacing of 400mm.

[0048] When withdrawing support, after the coal mining face advances, when withdrawing support facilities, first withdraw the direction pillars, then withdraw the inclined dense pillars, and install replacement pillars before withdrawing the inclined dense pillars. Before withdrawing, you must install the protective pillars and clear the retreat route. Retreat from bottom to top, from the old pond to the coal wall, first support and then retreat, first dense and then point pillars. Check the roof before retreating, and the pillar retreat operator should stand in a safe place above the sidewalk on the new dense side of the coal wall. Use a retreat handle rope with a length greater than 3m for long-distance retreat. When encountering pillars that are difficult to withdraw, first use wood to make replacement materials before retreating, and the replacement materials must not be retreated again. The retreat order is from bottom to top, from dense to coal wall.

Claims

1. The steeply inclined coal seam downward pseudo-inclined mining process is to set up a return air lane and a machine lane with a lower horizontal position than the return air lane in the coal seam, and adopt the backfilling method. The coal mining working face is arranged between the return air lane and the machine lane. The coal mining machine is arranged on the coal mining working face to walk and cut coal, and support facilities are set up on the coal mining working face; The coal mining working face has an upper outlet near the return air lane and a lower outlet near the machine lane; it is characterized in that: Specifically: When the true inclination of the coal seam is above 70° and the average inclination length is above 100 meters, the upper outlet of the coal mining face arranged in the coal seam is 15-20mm ahead of the lower outlet, so that the pseudo inclination of the coal mining face is 58°-62°.

2. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 1, characterized in that: The method of walking and cutting coal by arranging the coal mining machine on the coal mining working face is: A feed section is provided at the upper outlet, and the feed section is arranged obliquely with the coal mining working face to form an angle of less than 8°; the coal mining machine gradually cuts into the coal wall when it moves, completing the feed; the first coal cutting is 0.8m; After the feed is completed, the coal is cut downward to the lower outlet, and the downward speed is not more than 3m / minute.

3. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 2, characterized in that: The length of the feed section is 25m-30m.

4. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 1, characterized in that: The support strength of the support facilities is greater than 280kN / m2.

5. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 4, characterized in that: The support facilities include a hydraulic support with a support strength greater than 386kN / m2; the top plate of the hydraulic support is parallel to the top plate of the coal mining face, the center line of the hydraulic support is parallel to the return air lane and the machine lane, and the center line of the hydraulic support forms an angle of 78-72° with the coal mining face.

6. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 5, characterized in that: The hydraulic support is continuously pushed forward along the direction of the coal mining face during mining to control the roof of the mining section. The maximum roof control distance is 5.64m, the minimum roof control distance is 4.84m, and the roof caving step distance is 0.8m. The hydraulic support pushes the conveyor. When pushing in each coal mining cycle, the conveyor section at the lower end of the coal mining working face is pushed first, and then the remaining conveyor sections are pushed upward step by step; The goaf area after the coal mining face is pushed through is treated by the full collapse method.

7. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 4, characterized in that: The length of the section without hydraulic support at the exit of the coal mining working face shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be added immediately; the length of the section without hydraulic support at the lower exit shall not be greater than 1.5m. If it is greater than 1.5m, hydraulic support shall be lowered; The lower exit section without hydraulic props is supported by a single hydraulic prop with a cap, the row spacing of the single hydraulic prop is 0.8m, the column spacing is 0.8m, the top control distance is between 4.34m and 5.14m, and the top release step distance is 0.8m.

8. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 4, characterized in that: The pedestrian safety exit section at the lower exit is supported by a single hydraulic support with a wooden cantilever board. The specifications of the wooden cantilever board are: 200mm long, 100mm wide, and 50mm thick. Among them, the density of single hydraulic pillars is not less than 0.8 pillars / m2, the row spacing of single hydraulic pillars is 0.8m, and the pillar spacing is 0.8m.

9. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 8, characterized in that: A row of inclined dense pillars are arranged close to the coal wall side of the pedestrian safety exit section at the lower exit, with a column spacing of 400mm; a row of walking pillars are built close to the top beam of the first support frame in the pedestrian safety exit section at the lower exit, with a column spacing of 400mm.

10. The steeply inclined coal seam downward pseudo-inclined mining process according to claim 9, characterized in that: After the coal mining face advances, when withdrawing the support facilities, first withdraw the walking pillars, then withdraw the inclined dense pillars, and before withdrawing the inclined dense pillars, set up the replacement pillars.

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