Mining method for remaining triangular coal in double-wing mining area of pseudo-inclined coal face

Abstract

The invention relates to a method for mining residual triangular coal in a double-wing mining area of a pseudo-inclined coal face, which is used for solving the problem that the triangular coal is difficult to recover after the double-wing mining of a steeply inclined coal seam. The method is characterized in that when the distance between the ends of the two working faces reaches the limited distance, mining of the first working face completing circulation at first is stopped, and the first working face is synchronously transformed into a multifunctional roadway with the ventilation, lifting and staggered feeding functions; and then, the second working face continues to advance, a hydraulic support withdrawn from a lower outlet of the second working face is transferred to the upper end through a horizontal pulling winch and a lifting winch to be recycled and reused, and triangular coal is gradually stoped by implementing the staggered cutting feed technology in the multifunctional roadway. According to the method, on the premise that compatibility with a ventilation system of the gob-side entry retaining process is guaranteed, efficient recovery of triangular coal is achieved, more 8000 tons of coal is mined in each mining area, meanwhile, the turnover efficiency of the hydraulic support is remarkably improved, and the equipment transfer cost and workload are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a coal mining method, in particular to a method for mining residual triangular coal in a double-wing mining area of a coal mining face. BACKGROUND

[0002] In underground coal mining, the arrangement of a coal mining face is generally in a double-wing (left-wing and right-wing) opposite mining arrangement. Since the coal mining face is arranged in a pseudo-inclined manner, after the two opposite working faces in each section are mined, residual triangular coal is left. Specifically, the left and right wing coal mining faces are opposite to each other and form a trapezoid with the machine roadway and the airway. When the left and right wing coal mining faces reach the stop line, the upper ends of the two working faces meet, and the mining equipment and facilities cannot be arranged, so the mining must be stopped. The triangle formed by the left and right wing coal mining faces and the machine roadway 3 and the airway 4 is the residual triangular coal.

[0003] When the coal thickness is 1.2m, the distance between the airway and the machine roadway is 175m, the average pseudo-inclined angle of the coal mining face is 60°, and the average true-inclined angle of the coal seam exceeds 70°, the layer angle is 80° (the angle between the coal mining face and the machine roadway). When the two working faces stop mining at a distance of 5m from the upper end, the distance between the lower outlets of the two working faces is about 67m, and the residual mining area is more than 6400 square meters, which is about 8000 tons of coal that cannot be mined. The coal resources in the triangular coal cannot be recovered and are wasted.

[0004] Therefore, it is very important to study the method for recovering the residual triangular coal in the double-wing working face in order to improve the recovery rate of coal resources.

[0005] Patent CN102182459A discloses a method for recovering residual triangular coal in a double-wing working face using a flexible shield support coal mining method. Figure 1 When the upper ends of the two working faces meet, the shield supports (i.e. hydraulic supports 6) of the two working faces, the transport machine roadway, and the connection between the shield supports are connected together to continue mining on the left side while the right side supports are kept supporting. During the mining process, the right side shield supports are continuously pulled to the left side, and the excess supports are withdrawn until the residual triangular coal in the double-wing working face is recovered. This method cuts off the air supply to the working face through the air door 01 and uses the machine roadway 3 and the return air stone door 02 to form an air flow route.

[0006] However, this method has the following main defects: 1. The current gob-side entry retaining mining process is to use the machine lane left by the previous section as the air lane for ventilation, so the coal mining face needs to keep in communication with the air lane. In the method of the patent CN102182459A, when the shield supports at the upper end of the right and left wings are connected together, the ventilation between the coal mining face and the air lane will be cut off. Therefore, the method is not applicable to the current gob-side entry retaining mining process (Note: The gob-side entry retaining mining process discards less coal and has a higher recovery rate because no coal pillar is set).

[0007] 2. In the method of the patent CN102182459A, the shield supports at the right wing working face cannot be withdrawn in a centralized manner, and have to be withdrawn one by one when the left wing is mined, which occupies a large number of hydraulic supports 6 (about 110). The hydraulic support is a heavy asset equipment (25 million per unit, 110 units equivalent to 270 million), and if it cannot be withdrawn in time and put into the next mining area, it will be stranded for half a month, which will lead to a tight replacement between mining and supply, and seriously affect the input-output ratio of the mining area.

[0008] Therefore, we must design a new mining method for the triangular coal left in the double-wing mining area of the coal mining face with a pseudo-inclined downward mining process. SUMMARY

[0009] In order to solve the above technical problems, the present application provides a mining method for the triangular coal left in the double-wing mining area of the coal mining face with a pseudo-inclined downward mining process, which is used for mining the triangular coal left in the double-wing mining area when mining to the stop mining line, in the steeply inclined coal seam mined by the pseudo-inclined downward mining process; wherein the upper end of the coal mining face is connected to the air lane of the gob-side entry retaining lane of the previous section, and the lower outlet of the coal mining face is connected to the transportation lane of the gob-side entry retaining lane. The specific mining method comprises: stopping the first working face from mining; setting a gangue blocking facility at the lower outlet of the first working face, opening a hydraulic support lifting chamber, and installing a lifting winch opposite the upper end of the first working face in the air lane; starting to withdraw the coal mining machine, the scraper conveyor and the hydraulic support of the first working face, and increasing temporary support of the first working face as a multifunctional lane while withdrawing the hydraulic support, wherein the multifunctional lane at least functions as ventilation, lifting of the hydraulic support, and staggered cutting of the coal mining machine; strengthening the support of the triangular coal area air lane and the machine lane; continuing to advance the second working face; when the roof of the hydraulic support advances into the multifunctional lane, the hydraulic support advancing into the multifunctional lane stops advancing immediately, support for the multifunctional lane is added, and the remaining hydraulic supports continue to advance along the coal wall, which is repeated; when the coal mining machine cuts from above, the coal mining machine enters the multifunctional lane to cut in a staggered manner; With the second working face advancing forward, the upper end of the second working face is continuously merged into the multifunctional roadway, so that the second working face is continuously shortened until the second working face completes the triangular coal mining.

[0010] The mining method of the triangular coal left in the double-wing mining area of the coal mining face with the inclined downward mining method, as described above, wherein the timing of stopping the mining of the first working face is: When the upper end of the first working face reaches a distance within a limited distance from the upper end of the second working face, the mining of the first working face is stopped, and the working face is started to be withdrawn; the second working face continues to mine coal.

[0011] The mining method of the triangular coal left in the double-wing mining area of the coal mining face with the inclined downward mining method, as described above, wherein the first working face is specifically: The limited distance is specifically, So that: L = v (h1 + h2) Wherein, L is the limited distance, that is, the distance between the upper ends of the two working faces; V is the advancing speed of the second working face; h1 is the time required for the first working face to complete the withdrawal; h2 is the time required for the first working face to increase temporary support as a multifunctional roadway.

[0012] The mining method of the triangular coal left in the double-wing mining area of the coal mining face with the inclined downward mining method, as described above, wherein when the hydraulic support is withdrawn, the hydraulic support at the lower outlet of the first working face is started to be withdrawn, and the hydraulic support is pulled upward through the multifunctional roadway to the air roadway through the lifting winch for external transfer; The first working face is increased with temporary support as a multifunctional roadway, and the specific method is: When the hydraulic support is withdrawn, every time a certain number of hydraulic supports are withdrawn, that is, single props are set and gangue blocking plates are installed on the side of the multifunctional roadway close to the goaf, the roof of the multifunctional roadway is fixed, and the roof of the goaf is cut and pressure relieved.

[0013] The mining method of the triangular coal left in the double-wing mining area of the coal mining face with the inclined downward mining method, as described above, wherein when the second working face continues to advance forward, the hydraulic support is moved out of the working face from the lower outlet of the second working face, and is transferred to the lifting chamber and hung on the winch cable, and is transferred from the multifunctional roadway to the upper end of the second working face, and is supplemented and installed into the second working face or added to the support of the multifunctional roadway.

[0014] The method for mining the residual triangular coal of the double-wing mining area of the coal mining face with the inclined mining method as described above, wherein a flat pulling winch is arranged at the lower outlet of the multi-functional roadway on the side of the goaf of the multi-functional roadway, and the cable of the flat pulling winch extends to the lower outlet of the second coal mining face to pull the hydraulic support separated from the coal mining face to the support lifting chamber at the lower outlet of the second coal mining face; A hydraulic support lifting chamber is arranged at the lower outlet of the multi-functional roadway, and specifically, At the lower outlet of the multi-functional roadway, the upper side of the machine roadway is excavated to form a gentle slope, the gentle slope starts from the floor of the machine roadway, transitions to the floor of the multi-functional roadway, and is supported and reinforced; the lifting winch cable extends into the machine roadway to hang the hydraulic support and lift it up; A gangue blocking device is arranged at the lower outlet of the multi-functional roadway, and specifically, the blocking device is a one-way flap that opens in one direction towards the upper outlet, is arranged near the upper wall of the lifting chamber, and cuts off the multi-functional roadway; a gap is left between the lower edge of the one-way flap and the floor of the multi-functional roadway for the lifting winch cable to pass through.

[0015] The method for mining the residual triangular coal of the double-wing mining area of the coal mining face with the inclined mining method as described above, wherein the hydraulic support of the second coal mining face advances in a direction in which the central axis of the roof is perpendicular to the coal wall, and when the support of the multi-functional roadway is added, the hydraulic support is turned by pulling through the winch to make the central axis of the hydraulic support perpendicular to the axis of the multi-functional roadway.

[0016] The method for mining the residual triangular coal of the double-wing mining area of the coal mining face with the inclined mining method as described above, wherein the method for the coal mining machine to enter the second coal mining face at the upper end is as follows: After the coal mining machine cuts coal upwards, it retreats downwards to exceed one coal mining machine body position, then an entry hole that can accommodate one drum is opened on the coal wall at a distance of one cutting hole distance from the upper end of the coal wall, serving as a cutting hole for the lower drum of the coal mining machine; The cutting hole distance is n = m + r, n is the cutting hole distance, m is the center distance of the two drums of the coal mining machine, and r is the radius of the drum; The coal mining machine goes upwards, the upper drum is out of the coal wall into the multi-functional roadway, the lower drum is aligned with the cutting hole, then the flight bar conveyor is pushed to make the lower drum enter the cutting hole while the upper drum synchronously rubs into the side edge of the upper end of the coal wall, and the entry is completed; the drum is started and the coal is cut downwards.

[0017] The method for mining the residual triangular coal of the double-wing mining area of the coal mining face with the inclined mining method as described above, wherein during the continuous advancement of the second coal mining face, the upper end and the lower outlet of the second coal mining face can both withdraw the excess flight bar conveyors; When the flight bar conveyor is withdrawn, the length of the flight bar conveyor remaining at the upper end of the second coal mining face after the withdrawal can make the upper drum of the coal mining machine riding on the flight bar conveyor rub into the side edge of the upper end of the coal wall.

[0018] The mining method of the triangle coal left in the double-wing mining area of the coal mining face with the inclined downward mining method has the features that the number of the hydraulic supports of the second coal mining face is not less than 3 groups of hydraulic supports, and when the length of the second coal mining face is not enough to arrange 3 groups of hydraulic supports, the mining is stopped and all the facilities of the coal mining face are removed.

[0019] Technical effects of the present application: The present application can effectively mine the triangle coal, and more than 8000 tons of coal can be mined in each mining area, and the economic benefit is improved.

[0020] The present application is suitable for mining the triangle coal in the gob-side entry retaining mining process. The multifunctional entry 12 is always communicated and ventilated with the air entry 4, and is used for withdrawing the hydraulic support 6 into the air entry 4.

[0021] After the first coal mining face 1 is mined, the hydraulic support 6 can be immediately withdrawn without being left, so that the hydraulic support 6 can be timely withdrawn and put into the next mining area, the supply and demand replacement is eased, the balance of the supply and demand of mining and excavation is promoted, and the input-output ratio of the mining area is improved.

[0022] The support withdrawn from the lower outlet of the second coal mining face 2 is transported and lifted to the upper end, and the process is repeated, so that the characteristics of the multifunctional entry 12 are fully utilized. In the traditional method, the support withdrawn from the lower outlet is withdrawn from the mining area, and the method of the present application for transferring the hydraulic support 6 to the same coal mining face for reuse greatly saves the work amount of the support transfer. At the same time, the support is alternately transferred by the flat pulling winch 8 and the lifting winch 7, the cost is very low, the speed is fast, and the labor is saved.

[0023] The air flow route is clear and simple, the corner is reduced, and the gas accumulation is prevented. Figure 6 After the return air enters the machine entry 3 and enters the air entry 4 from the second coal mining face 2 and the multifunctional entry 12, the return air flow direction is formed.

[0024] When the coal mining machine 19 descends and cuts, the staggered cutting method is used, one cutting eye 22 can be less excavated, the structure of the second coal mining face 2 at the intersection with the multifunctional entry 12 is fully utilized, only one cutting eye 22 is needed to complete the cutting operation, and the excavation cost and construction period are effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the schematic diagram of the triangle coal mining method in the prior art patent CN102182459A.

[0026] Figure 2 is the plane layout schematic diagram of the mining method of the triangle coal left in the double-wing mining area of the coal mining face with the inclined downward mining method.

[0027] Figure 3is a process schematic diagram of the second working face advancing, showing the arrangement of each facility, the lifting process of the hydraulic support, and the structure of the second working face pushing into the multifunctional roadway. Figure 4 is a schematic diagram of the multifunctional roadway structure, showing the internal arrangement of the multifunctional roadway.

[0028] Figure 5 is a schematic diagram of the present invention using staggered cutting method when the coal mining machine advances downward; Figure 6 is a schematic diagram of the air flow route of the present invention, clearly showing the flow path of the return air from the machine roadway into the second working face and the multifunctional roadway into the air roadway.

[0029] Among them, return air stone door 02, air door 01, coal seam 03; first working face 1; second working face 2; machine roadway 3; air roadway 4; goaf 5; hydraulic support 6; lifting winch 7; flat pull winch 8; lifting chamber 9; gentle slope 10; turning plate 11; multifunctional roadway 12; anchor cable 13; anchor rod 14; I-beam 15; gangue blocking plate 16; coal mining machine 19; drum 20; scraper conveyor 21; open-off cut 22. DETAILED DESCRIPTION

[0030] Example one: arrangement of each device and facility in the working face and roadway.

[0031] In the steeply inclined coal seam 03 with a true dip angle of 70° or more, the coal mining face is arranged in a downward pseudo-inclined process, one working face is arranged on each side of a mining area, and the working face advances towards the middle, i.e. double-winged mining, after the two side mining working faces reach the stop line, the remaining triangular coal between the two side mining working faces.

[0032] The upper end of the coal mining working face is connected to the air roadway 4 of the gob-side entry retaining roadway of the previous section, and the lower outlet of the coal mining working face is connected to the transport roadway of the gob-side entry retaining roadway, and the transport roadway is treated as a gob-side entry retaining roadway to serve as the air roadway 4 of the next section.

[0033] After the first working face 1 reaches the stop line, it is converted into a multifunctional roadway 12, and a gangue blocking facility is arranged at the lower outlet of the multifunctional roadway 12 to block the impact gangue falling from the multifunctional roadway 12, so as to avoid injuring people and equipment working and passing through the lower outlet. Figure 3The gangue blocking facility is specifically a gangue blocking flap 11, which is a one-way flap 11 that opens in one direction towards the upper outlet direction, and is located near the upper wall of the lifting chamber 9. The one-way flap 11 cuts off the multifunctional roadway 12. The flap 11 is made of steel material, and reinforcing ribs are welded on the surface to ensure that it does not deform when subjected to the impact of the gangue. The rotating shaft of the flap 11 is installed on the side of the goaf 5, and the rotating shaft can be welded on the I-beam 15 supported at this position. A I-beam 15 is additionally arranged at the position corresponding to the door shaft on the side close to the coal wall, which is used as a limit door stop when the flap 11 is closed. The door stop is located on the side of the flap 11 close to the machine roadway 3, and ensures that it is always in an effective interception state in a non-passing state. When the cable of the lifting winch 7 pulls the support through, the flap 11 can be pushed open, and then automatically returns to close under the action of gravity (or a return spring can be installed on the door shaft), effectively preventing the gangue in the goaf 5 from entering the roadway. When the flap 11 is closed, a large enough door gap is left to ensure that the multifunctional roadway 12 is connected with the upper section airway 4, and the ventilation is smooth.

[0034] A hydraulic support 6 lifting chamber 9 is arranged at the lower outlet of the multifunctional roadway 12. The lifting chamber 9 is supported in the goaf 5, so that the space of the lifting chamber 9 extends into the goaf 5, and is well supported. The coal wall side is also expanded, thereby expanding the space at the lower outlet of the multifunctional roadway 12, which is used for pulling the hydraulic support 6 to this position for convenient turning and reversing. The width and length of the lifting chamber 9 are at least 3m, and preferably the lower outlet of the multifunctional roadway 12 is expanded on both sides, and the shape is roughly a trumpet mouth.

[0035] The lifting chamber 9 extends into the machine roadway 3. In the lifting chamber 9, the upper side of the machine roadway 3 is excavated to form a gentle slope 10. The gentle slope 10 starts from the floor of the machine roadway 3 (preferably from the inner neck of the trumpet mouth), and transitions to the floor of the multifunctional roadway 12. The pseudo-inclination angle of the floor of the multifunctional roadway 12 is 60°, and the floor of the machine roadway 3 is horizontal. The transition slope can be set to 75° (the included angle with the horizontal plane), and is arc-shaped with the floor of the multifunctional roadway 12, so that the hydraulic support 6 can be smoothly lifted, and the hydraulic support 6 can be directly pulled from the machine roadway 3 into the multifunctional roadway 12.

[0036] Another example is that if the lifting chamber 9 is not arranged, the hydraulic support 6 needs to be pulled to the lifting platform first, turned and reversed on the lifting platform, then lifted to the height of the roadway upper side, and then pulled into the multifunctional roadway 12. This operation is complicated and labor-intensive, and a lifting platform also needs to be installed on site.

[0037] A lifting winch 7 is installed in the airway 4 opposite the upper end of the multifunctional roadway 12. The cable of the lifting winch 7 extends out into the lifting chamber 9 and can be hung on the floor of the hydraulic support 6.

[0038] The lifting chamber 9 is supported, including supporting the I-beams 15 on the side of the lifting chamber close to the goaf 5, the I-beams 15 are spaced 800 mm apart, a column foot is added to the lower end, and a wooden wedge is used to tighten the upper end, a baffle is arranged behind the I-beams 15 and a steel mesh is arranged, and top cutting and pressure relief are performed behind the I-beams 15 to separate the roof of the lifting chamber 9 from the goaf 5, the roof in the lifting chamber 9 is supported, and a T-shaped steel belt, an anchor cable 13, and a steel mesh are used as permanent support, two rows of anchor rods 14 are supported by being inserted into the coal seam 03 in a direction perpendicular to the roof, the anchor rods 14 are L = 1800 mm and φ = 18 mm threaded steel resin anchor rods 14, and a steel strand anchor cable 13 with a length of 5180 mm and a diameter of 17.8 mm is used as a reinforcing support, a row of anchor cables 13 is arranged on the side close to the goaf 5, and a T-shaped steel belt is hung, and a flat iron steel belt is used to lock the wall along one side of the coal wall, and a steel mesh is used to prevent the coal wall from falling and prevent the falling of the debris. The anchor cables 13 are spaced 1500 mm x 1500 mm apart to ensure that the support strength meets the roof stability requirements during the support transfer. When the second working face 2 is advanced to about 20 m from the lifting chamber 9, the stability and bearing capacity of the support structure are detected, the second working face 2 is affected by mining, stress monitoring and displacement observation are performed on the support section of the lifting chamber 9, and it is confirmed that the stress changes of the I-beams 15, the anchor rods 14, and the anchor cables 13 are within a safe range. If the roof subsidence or coal wall spalling risk is found, the support is reinforced in time, the reinforcement mainly adds a hydraulic point column, one single hydraulic support is added between each I-beam 15, the column top is tightly attached to the T-shaped steel belt, the base is placed on the stable floor and the column shoe is penetrated, and the overall stability of the support system is ensured. At the same time, on-site inspection is strengthened, the deformation of the surrounding rock is observed in real time, the support parameters are dynamically adjusted combined with the stress monitoring data, and the safe passing conditions of the lifting chamber 9 during the support transfer are ensured.

[0039] The hydraulic supports 6 of the first working face 1 are withdrawn while the first working face 1 is supported and the roof is cut and pressure relieved. The roof of the goaf 5 is pre-split blasted to weaken the integrity of the roof, promote its timely collapse, and reduce the suspended roof area. Referring to Figures 3-4After each hydraulic support unit is installed (number 6), dense support pillars are implemented in the withdrawal section, including individual hydraulic supports spaced 0.8m apart. Following the individual supports, H-beams (number 15) are installed along the strike direction, with each H-beam (number 15) supporting two individual supports. Metal mesh is laid on the H-beams (number 15) and securely connected to the top beam of the support structure to ensure effective support of the roof of the goaf (number 5), preventing local collapse and serving as roof-cutting supports. The H-beams (number 15) and individual supports are installed 2m away from the coal face, corresponding to a 2m width in the converted multi-purpose roadway. After each set of three hydraulic supports 6 is withdrawn, the roadway is reinforced, including installing two rows of anchor cables 13 with a spacing of 1500mm in the roadway. The anchor cables 13 penetrate into the stable rock layer for no less than 2.5m and the preload is no less than 120kN. Three rows of anchor rods 14 with a spacing of 800mm×800mm are also installed. The anchor rods 14 are made of L=1800mm and φ=18mm threaded steel resin anchor rods 14. Together with the installed anchor mesh and T-shaped steel strips, they form an integral load-bearing body with the I-beams 15 and point column supports to enhance the stability of the surrounding rock. At the same time, rock-blocking curtains and rock-blocking plates 16 are added on both sides of the goaf to prevent debris from entering the working area during collapse. Every 2m of hydraulic support 6 is withdrawn, a roof-cutting blasting operation is carried out. The blasting holes are arranged along the sides of the goaf 5 of the I-beam 15 and the single support, with a hole spacing of 500mm and a hole depth of 5m. The blasting holes are inclined towards the goaf 5 side, forming an 85° angle with the horizontal plane. A shaped charge tube is installed inside the blasting hole, with its cut direction aligned with the pre-splitting line. The shaped charge tube is made of PVC pipe, with a diameter of 40mm and a length of 2000mm. Based on the deep-hole pre-splitting blasting hole diameter and the emulsion explosive diameter of Φ32mm×330mm / roll used in the mine, a Class III coal mine-specific emulsion explosive is selected, using millisecond delay electric detonators. A series single-stage detonation is employed, with a maximum of no more than 6 blasting holes. The blasting length along the roadway is approximately 3m. After roof cutting is completed, the working face is converted into multi-functional roadway 12.

[0040] Strengthen the support of ventilation roadway 4 and machine roadway 3 in the triangular coal area. This includes adding point pillars, H-beams 15, and adding anchor cables 13 and anchor bolts 14, etc., to reduce the range of roadways affected by mining and improve the support strength.

[0041] A winch is installed in ventilation tunnel 4 directly above multi-functional tunnel 12 (i.e., the first working face 1 before the modification). It is used to lift hydraulic support 6.

[0042] At the lower exit of multi-functional roadway 12 (i.e., the first working face 1 before modification), near the goaf 5 side of multi-functional roadway 12, a horizontal winch 8 is installed. The cable of the horizontal winch 8 extends to the lower exit of the second working face 2 and is used to connect to the bottom plate of the hydraulic support 6 to be lifted. A gap is left between the lower edge of the one-way flap 11 and the bottom plate of multi-functional roadway 12 for the cable to pass through.

[0043] The section without hydraulic props at the lower exit of the second working face adopts single hydraulic props with caps for support. The row spacing and column spacing are both 0.8m, the jacking distance is 4.34–5.14m, and the jacking step distance is 0.8m.

[0044] The pedestrian safety exit section at the lower exit uses single hydraulic props in conjunction with wooden planks for support. The wooden plank dimensions are: length × width × thickness = 200mm × 100mm × 50mm. The prop density is no less than 0.8 props / m². 2 The row spacing and column spacing are both 0.8m. A row of inclined, densely packed supports is arranged on the side of the coal face, with a column spacing of 400mm. A row of directional supports is installed at the top beam of the first hydraulic support 6 near the lower outlet, with a column spacing of 400mm.

[0045] The working face uses hydraulic support 6, with the support roof controlled at 1.5m to prevent the support from biting. Anti-tipping ropes must be fastened between the supports. The working range of hydraulic support 6 is 0.8m to 1.5m (equivalent to the mining height of coal seam 03).

[0046] Example 2: Coal mining steps.

[0047] Step 01: Stop mining at the first working face 1.

[0048] When the upper ends of the two working faces reach within a limited distance, the working face of either the left or right wing completes the coal mining cycle first. At this time, the coal mining machine 19 in the working face that completes the coal mining cycle first moves upward to cut coal and reaches the upper end. The working face collects floating coal to the scraper conveyor 21. The working face that completes the cycle first is the first working face 1, regardless of whether it is the left or right wing working face.

[0049] The specified distance here is used to determine when to stop mining at the first working face 1. When the upper ends of both working faces reach within the specified distance, mining at the first working face 1 ceases, and the withdrawal from the working face begins; mining at the second working face 2 continues. This specified distance is calculated using the following formula: L = v(h1 + h2); where L is the defined distance, i.e., the distance between the ends of the two working faces; V is the advancing speed of the second working face 2; h1 is the time required for the first working face 1 to complete its retreat; h2 is the time required to add temporary support to the first working face 1 to convert it into a multi-functional roadway 12. For example: in a 180m long coal mining face, one shift (one shift in an 8-hour system) allows the coal mining machine 19 to complete at least one coal mining cycle (one downward and one upward movement of the coal mining machine 19 constitutes one cycle), with a cutting depth of 0.8m per cycle (i.e., advancing 1.6m per shift), taking into account the time for equipment maintenance, troubleshooting, etc.; it takes 10 days to complete the retreat of the equipment from the first working face 1 and convert it into a multi-functional roadway 12; therefore, when the distance between the ends of the two working faces is about 50m, the first working face 1 stops mining, which allows the first working face 1 to mine as much coal as possible without delaying the conversion into a working face, avoiding the situation where the second working face 2 advances to the first working face 1 before the conversion is completed and the machine stops, affecting the coal mining efficiency.

[0050] Step 02: Begin withdrawing the coal mining machine 19 and scraper conveyor 21 from the first working face 1.

[0051] Step 03: Retract part of the hydraulic support 6 near the lower exit; open the hydraulic support 6 lifting chamber 9. Specifically: at the lower exit of the multi-functional tunnel 12, excavate the upper side of the machine tunnel 3 to form a gentle slope 10. The gentle slope 10 starts from the bottom plate of the machine tunnel 3 and transitions to the bottom plate of the multi-functional tunnel 12, and is supported and reinforced; the hoisting winch 7 cable extends into the machine tunnel 3 to hook the hydraulic support 6 and lift it up; a rock-blocking facility is set at the lower exit of the multi-functional tunnel 12, specifically: the barrier facility is a one-way flap 11 that opens in one direction towards the upper exit, located near the upper wall of the lifting chamber 9, and the one-way flap 11 cuts off the multi-functional tunnel 12; a gap is left between the lower edge of the one-way flap 11 and the bottom plate of the multi-functional tunnel 12 for the hoisting winch 7 cable to pass through.

[0052] A rock-blocking flap 11 is installed at the lower exit of the first working face 1, and a hoisting winch 7 is installed in the ventilation tunnel 4 directly opposite the upper end of the first working face 1.

[0053] Step 04: Continue withdrawing the hydraulic support 6. Simultaneously, add temporary support to the first working face 1 to create a multi-functional roadway 12 for ventilation, hoisting the hydraulic support 6, and staggered cutting of the coal mining machine 19. The withdrawn hydraulic support 6 is pulled up through the first working face 1 via the hoisting winch 7 to the ventilation roadway 4 for external transport.

[0054] When withdrawing hydraulic supports 6, after withdrawing three sets of hydraulic supports 6, a single prop is installed and a retaining wall 16 is installed on the side of the multi-functional roadway 12 near the goaf 5 where the hydraulic supports 6 have been withdrawn, to fix the roof of the multi-functional roadway 12. The roof of the goaf 5 is then cut to relieve pressure.

[0055] At the lower exit of multi-functional roadway 12, near the goaf 5 side of multi-functional roadway 12, a horizontal winch 8 is installed. The cable of the horizontal winch 8 extends to the lower exit of the second working face 2, and pulls the hydraulic support 6, which has been removed from the working face at the lower exit of the second working face 2, to the support lifting chamber 9.

[0056] Step 05: Strengthen the support of ventilation roadway 4 and machine roadway 3 in the triangular coal area.

[0057] Step 06: After the above modifications are completed, the second working face 2 will be advanced to a position where the upper end is less than 5m away from the upper end of the first working face 1. If the modification is not completed when the second working face 2 is advanced to a position where the upper end is less than 2m away from the upper end of the first working face 1, the machine will be stopped and the process will wait.

[0058] After the modification is completed, when the second working face 2 continues to advance, the hydraulic support 6 that is removed from the working face will be moved out of the lower outlet of the second working face 2. The hydraulic support 6 can then be transferred to the hoisting chamber 9 and a winch cable will be attached. It will then be transferred from the multi-functional tunnel 12 to the upper end of the second working face 2 and installed in the second working face 2 or added to the support of the multi-functional tunnel 12.

[0059] Step 07: When the hydraulic support 6 of the second working face 2 is advanced into the multi-functional roadway 12, the hydraulic support 6 that has advanced into the multi-functional roadway 12 immediately stops advancing and adds support to the multi-functional roadway 12. The remaining hydraulic supports 6 continue to advance with the coal wall, and this process is repeated. The hydraulic supports 6 of the second working face 2 advance in a direction perpendicular to the coal wall with the central axis of the roof. When adding support to the multi-functional roadway 12, the hydraulic supports 6 are turned by the winch, so that the central axis of the hydraulic supports 6 is perpendicular to the axis of the multi-functional roadway 12.

[0060] When the second working face 2 advances into the multi-functional roadway 12, the coal mining machine 19 can use a staggered cutting method when it descends. The specific steps are as follows: Step 11: After the coal mining machine 19 has finished cutting the coal upwards, it needs to retract downwards beyond the length of one mining machine body to create space for the construction workers to use drill rods to open the cutting hole 22. (Reference) Figure 5 A cutting hole, large enough to accommodate one drum 20, is made on the coal face at a distance of one cutting edge from the upper end of the coal face. This is the cutting edge 22 of the lower drum 20 of the coal mining machine 19. The cutting edge distance is: n = m + r, where n is the cutting edge distance, m is the center distance between the two drums 20 of the coal mining machine 19, and r is the radius of the drum 20.

[0061] Step 21: The upward coal mining machine 19 moves to the upper drum 20 to pick up the coal wall outside into the multi-functional roadway 12. The lower drum 20 is aligned with the opening cut 22. Then the scraper conveyor 21 is pushed to make the lower drum 20 align into the opening cut 22 while the upper drum 20 simultaneously scrapes into the upper end side of the coal wall to complete the cutting. The drum 20 is started and moves downward to cut the coal.

[0062] As the second working face 2 continues to advance, the excess scraper conveyor 21 can be removed from both the upper head and the lower outlet of the second working face 2. Considering whether the head of the scraper conveyor 21 is at the upper or lower end, the excess scraper conveyor 21 is usually removed from the tail end of the scraper conveyor 21.

[0063] When the scraper conveyor 21 is withdrawn, the length of the scraper conveyor 21 remaining at the upper end of the second working face 2 is always maintained so that the upper roller 20 of the coal mining machine 19, which straddles the scraper conveyor 21, can be rubbed into the side of the upper end of the coal wall, so that the coal mining machine 19 can use staggered cutting.

[0064] As the second working face 2 advances forward, its upper end continuously merges into the multi-functional roadway 12, causing the second working face 2 to shorten continuously. The number of hydraulic supports 6 on the second working face 2 also decreases continuously. When the number of hydraulic supports 6 approaches 3 sets, the length of the working face is less than 8m, and the coal mining machine 19 has basically no travel distance. At this point, mining is stopped, and all facilities on the working face are removed.

[0065] Example 3: In a certain mine, two working faces are being mined in one mining area, with one working face having a strike length of 800m. The average thickness of coal seam 03 is 1.2m. (Reference) Figure 2 Wherein, AB is ventilation roadway 4, CD is machine roadway 3, ABCD is coal seam 03, and the average true dip angle of coal seam 03 exceeds 70°. CEFD is the horizontal plane, and GHJK is the remaining triangular coal. GJ is the first working face 1, and KH is the second working face 2. Both the first working face 1 and the second working face 2 are pseudo-inclined working faces, and the average angle between the pseudo-inclined working faces and the horizontal plane is 60°. Therefore, the face angle α (or α') is 78°~82° (the angle between the working face and ventilation roadway 4), and an average of 80° is taken. When the distance between the upper ends of the two working faces is 5m, mining stops, and the distance between the lower exits of the two working faces will be about 67m. The remaining mining area will reach more than 6400 square meters, about 8000 tons of coal. Using the triangular coal mining method, mining stops at the second working face 2. The remaining triangular coal area is about 12 square meters, and the total mining rate of triangular coal exceeds 99%, which can be regarded as the complete mining of triangular coal.

[0066] Economic benefits: The complete mining of the triangular coalfield will recover an additional 77,000 tons of coal resources, with an average selling price of 280 yuan / ton, resulting in a coal value of 21.56 million yuan.

[0067] The resulting airflow path is clear and concise, minimizing corner angles and preventing gas accumulation. (Reference) Figure 6 The return air enters from machine roadway 3, and then enters ventilation roadway 4 from the second working face 2 and multi-functional roadway 12, forming the return air flow direction.

Claims

1. A method for mining the remaining triangular coal in the double-wing mining area of ​​a pseudo-inclined coal face, used for mining the triangular coal remaining when mining to the stop line in steeply inclined coal seams using the pseudo-inclined mining technique; wherein, The upper end of the coal mining face is connected to the ventilation roadway of the previous section's gob-side retaining roadway, and the lower outlet of the coal mining face is connected to the haulage roadway of the gob-side retaining roadway; its characteristic is that the specific mining method includes: Mining at the first working face has ceased. A rock-blocking facility is installed at the lower exit of the first working face, and a hydraulic support lifting chamber is opened. A hoisting winch is installed in the ventilation tunnel directly opposite the upper end of the first working face. The process begins with the withdrawal of the coal mining machine, scraper conveyor, and hydraulic support from the first working face; and while withdrawing the hydraulic support, temporary support is added to the first working face to create a multi-functional roadway. The work of the multi-functional roadway includes at least ventilation, lifting the hydraulic support, and staggered cutting of the coal mining machine. Strengthen the support of ventilation and machine roadways in the triangular coal area; The second working face continues to advance; When a hydraulic support is advanced into the multi-functional roadway, the hydraulic support that has been advanced into the multi-functional roadway stops advancing and adds support to the multi-functional roadway. The remaining hydraulic supports continue to advance along the coal wall, and this process is repeated. When the coal mining machine advances from above, it enters the multi-functional roadway for staggered cutting. As the second working face advances, its upper end continuously merges into the multi-functional roadway, causing the second working face to shorten until the triangular coal mining is completed.

2. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, The time to stop mining at the first working face is: When the upper end of the first working face is within a certain distance from the upper end of the second working face, the first working face stops mining and begins to withdraw from the working face; the second working face continues mining.

3. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 2, characterized in that, Specifically, when the upper ends of two working faces reach within a limited distance, the working face that completes one coal mining cycle first is taken as the first working face. At this time, the coal mining machine in the working face completes the upward coal cutting and reaches the upper end, completing the collection of floating coal from the working face to the scraper conveyor. The specified distance is, in particular, Make: L = v(h1 + h2) Where L is the defined distance, i.e. the distance between the upper ends of the two working faces; V is the advancing speed of the second working face; h1 is the time required for the first working face to complete the withdrawal; and h2 is the time required to add temporary support to the first working face to make it a multi-functional roadway.

4. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, When withdrawing the hydraulic support, the withdrawal begins from the hydraulic support at the lower exit of the first working face. The hydraulic support is then pulled upward through the multi-functional tunnel to the ventilation tunnel and transferred outward by the hoisting winch. The method for adding temporary support to the first working face to create a multi-functional roadway is as follows: When removing the hydraulic supports, after removing several sets of hydraulic supports, single pillars are installed and retaining walls are installed on the side of the multi-functional roadway near the goaf where the hydraulic supports have been removed, the roof of the multi-functional roadway is fixed, and the roof of the goaf is cut to relieve pressure.

5. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, As the second working face continues to advance, the hydraulic support that has detached from the working face is removed from the lower exit of the second working face, and the hydraulic support is transferred to the hoisting chamber. The winch cable is then attached, and the support is transferred from the multi-functional tunnel to the upper part of the second working face. It is then installed in the second working face or added to the support of the multi-functional tunnel.

6. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 5, characterized in that, At the lower exit of the multi-functional roadway, a horizontal winch is installed on the side of the goaf area of ​​the multi-functional roadway. The cable of the horizontal winch extends to the lower exit of the second working face and pulls the hydraulic support that has been moved out of the working face from the lower exit of the second working face to the support lifting chamber. A hydraulic support lifting chamber is set up at the lower exit of the multi-functional tunnel, specifically as follows: At the lower exit of the multi-functional tunnel, the upper side of the machine tunnel is excavated to form a gentle slope. The gentle slope starts from the bottom plate of the machine tunnel and transitions to the bottom plate of the multi-functional tunnel, and is supported and reinforced. The hoisting winch cable is extended into the machine tunnel to hook the hydraulic support and lift it up. A rock-blocking facility is installed at the lower exit of the multi-functional tunnel. Specifically, the barrier is a one-way flap that opens in one direction towards the upper exit and is located near the upper wall of the hoisting chamber. The one-way flap cuts off the multi-functional tunnel. A door gap is left between the lower edge of the one-way flap and the bottom plate of the multi-functional tunnel for the hoisting winch cable to pass through.

7. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 6, characterized in that, The hydraulic support of the second working face is advanced in a direction perpendicular to the coal wall with the central axis of the roof. When the support for the multi-functional roadway is added, the hydraulic support is turned by the winch so that the central axis of the hydraulic support is perpendicular to the axis of the multi-functional roadway.

8. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, The method of feed for the coal mining machine at the upper end of the second working face is as follows: After the coal mining machine moves upward and cuts the coal, it moves downward and moves beyond the length of one coal mining machine body. Then, a cutting hole that can accommodate one roller is opened on the coal wall at a distance of one cutting hole from the upper end of the coal wall. This hole serves as the cutting hole for the lower roller of the coal mining machine. The cut-eye distance is: n=m+r, where n is the cut-eye distance, m is the center distance between the two drums of the coal mining machine, and r is the drum radius; The upward-moving coal mining machine moves the upper drum out of the coal wall into the multi-functional roadway, aligns the lower drum with the cutting eye, and then pushes the scraper conveyor so that the lower drum enters the cutting eye while the upper drum simultaneously scrapes into the upper end of the coal wall to complete the cutting; the drum is then started and moves downward to cut the coal.

9. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, As the second working face continues to advance, excess scraper conveyors can be removed from both the upper end and the lower outlet of the second working face. When withdrawing the scraper conveyor, always maintain the length of the scraper conveyor remaining at the upper end of the second working face after withdrawal, so that the upper roller of the coal mining machine riding on the scraper conveyor can be rubbed into the upper end side of the coal wall.

10. The method for mining the remaining triangular coal in the double-wing mining area of ​​the pseudo-inclined coal face as described in claim 1, characterized in that, The number of hydraulic supports in the second working face shall be at least three sets. When the length of the second working face is insufficient to accommodate three sets of hydraulic supports, mining shall be stopped and all facilities in the working face shall be removed.

Images