A backfill mining method for steeply inclined coal seams and its application

Abstract

This invention provides a backfill mining method for steeply inclined coal seams. It utilizes a continuous miner with its own temporary support and uses gravity to fill branch lanes. Currently, the flexible shielded support blasting process commonly used in steeply inclined coal seams is inefficient, unsafe, and poses a harsh working environment, leading to its prohibition by local governments. This invention effectively addresses this issue.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining and transportation, and more specifically, relates to a backfill mining method for a steeply inclined coal seam and its application. Background Art

[0002] At present, the flexible shield support blasting production process is generally used in steeply inclined coal seams. Its low efficiency, poor safety and harsh working environment have made it banned by local governments. Ordinary continuous miners can only be used in near-horizontal coal seams. For a long time, there has been no mature mining equipment system for steeply inclined coal seams. As a result, steeply inclined coal seams cannot be fully mined and utilized, resulting in a waste of resources. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a filling mining method for steeply inclined coal seams and its application, which can mine steeply inclined coal seams safely and efficiently.

[0004] The technical solution adopted by the present invention is: a backfill mining method for steeply inclined coal seams, comprising the following steps:

[0005] (1) Excavation and transportation tunnel, return air tunnel and cut: Excavation and transportation tunnel and return air tunnel are arranged according to the direction of the longwall working face system. Coal gangue belt conveyor and mixed slurry pipeline are arranged in the upper return air tunnel, and raw coal scraper conveyor is arranged in the lower transportation tunnel; at the designed cut position, a pseudo-inclined side cut with a pseudo-inclination angle of no more than 45° is opened by a steeply inclined continuous miner with its own temporary support as a permanent ventilation pedestrian passage for this working face;

[0006] (2) Then, a steeply inclined continuous mining machine with its own temporary support is used to mine a pseudo-inclined branch tunnel Z1 with a width of 3-8m at a distance of 3-8m from the side cut. After mining, a coal pillar M1 with a width of 3-8m is left to mine Z2, and branch tunnels Z3, Z4, Z5, etc. are mined in turn, while leaving several coal pillars M2, M3, M4, etc.

[0007] (3) A gangue delivery hole is constructed from the ground to the underground, and the gangue is transported to the upper opening of the Z1 branch tunnel by the gangue belt conveyor 17; at the same time, a ground slurry station is constructed to mix fly ash, cement and other additives into a mixed slurry, which is then transported to the upper opening of the Z1 branch tunnel through the mixed slurry pipeline 16.

[0008] (4) The slurry blocking robot 4 with patent application number CN201921954702.8 is used to seal the lower mouth of branch tunnel Z1. The slurry blocking robot has a slurry pressure detection function and can alarm when the pressure value reaches the robot's slurry blocking rated value.

[0009] (5) Gangue and mixed slurry are added at the same time at the top of branch tunnel Z1. The gangue and mixed slurry are mixed evenly while rolling down. The pressure of the slurry on the slurry blocking robot 4 is monitored at any time. When the alarm is triggered, filling is stopped. Filling can be continued when the pressure drops below the set pressure.

[0010] (6) After filling Z1, move the slurry blocking robot 4 to the lower opening of Z2 and fill Z2, Z3, Z4, etc. in sequence according to steps 4 and 5.

[0011] (7) When the filling strength of the branch tunnel reaches the designed strength, the coal pillars M1, M2, M3, etc. are mined using a steeply inclined continuous mining machine with its own temporary support.

[0012] (8) Then fill M1, M2, M3, etc. according to the steps. At this time, only the lower 3-8m can be filled to meet the requirements of retaining lanes.

[0013] The continuous mining machine includes a coal mining device, a coal loading mechanism, a coal transporting mechanism, a pushing mechanism and a pipe and cable wind tube supporting and moving device. The coal mining device is a cutting head driven by a hydraulic motor; the coal loading mechanism is a crab claw loader driven by a motor; the coal transporting mechanism is a scraper conveyor driven by a motor, which transports the coal out of the continuous mining machine and then flows to the level tunnel transfer machine 13 by gravity; the coal mining device is connected to the pushing mechanism, and the pushing mechanism includes a front base and a rear base, which are connected by a pushing cylinder, and front pressure columns are provided on both sides of the front base, and rear pressure columns are provided on both sides of the rear base. The cable wind tube support and moving device consists of a synchronous winch, a guide pulley and a wire rope. The guide pulley is arranged on the front base and is connected to the synchronous winch arranged in the lower level tunnel through a wire rope. The continuous miner also includes a motor and an oil pump that provide hydraulic energy for the entire machine; the hydraulic motor, the push cylinder, the synchronous winch, the front pressure column cylinder that controls the front pressure column, and the rear pressure column cylinder that controls the rear pressure column are all controlled by a control system, and the control system is integrated into the remote control.

[0014] The method of using the steeply inclined continuous miner with its own temporary support is as follows:

[0015] The two front pressure columns are lowered to a certain height, and the push cylinders push the mining section forward to cut coal. When the push cylinders reach their maximum stroke (L), cutting stops and the front pressure columns are raised as temporary support. Bolting is then carried out under this temporary support. The rear pressure columns are then lowered, the push jacks are retracted, and the rear pressure columns are moved up a distance (L) before being raised. Simultaneously, the synchronized winch is activated to move the wire rope up the same distance (L), beginning the next coal cutting cycle. Support is applied at the right time depending on roof conditions and can be performed in front of or behind the continuous miner. If the roof is hard and no support is required, control can be performed from the lower level control room, allowing for unmanned working. After mining a branch lane, the steeply inclined, self-supporting continuous miner is withdrawn from the top. Only the rear pressure columns and push cylinders are used to lower the machine. This operation involves lowering the rear pressure columns and retracting the push cylinders, allowing the continuous miner to retreat a distance (L) while simultaneously clearing away loose coal. Repeat the above operations to make the continuous mining machine retreat to the lower level tunnel and carry out coal mining in the next branch tunnel.

[0016] The invention discloses an application of a backfill mining method for steeply inclined coal seams. The method is also suitable for mining three-down coal in coal seams with an inclination angle between 12° and 45°.

[0017] The continuous miner of the present invention is equipped with front and rear pressure columns that can be rotated to form temporary support. A thrust cylinder is provided to propel the mining device forward, enabling continuous mining. A cable and wind tube support device randomly moves the power cables, ventilation ducts, water pipes for dust suppression and cooling, and control cables for the continuous miner. This invention enables mining in inclined coal seams. The temporary support ensures safety even when personnel are required to perform bolting, making mining in steeply inclined coal seams safe and efficient.

[0018] The natural inclination of the coal seam is utilized and filling is carried out relying on natural forces. During filling, the slurry and gangue are mixed evenly during the falling process, making the filling body more solid. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall arrangement of the present invention.

[0020] Figure 2 The present invention Figure 1 AA direction cross-sectional view;

[0021] Figure 3 Shown is a schematic structural diagram of the continuous miner of the present invention;

[0022] Figure 4 The figure shows a cross-sectional view of the continuous miner of the present invention taken along the AA direction;

[0023] Figure 5 This is a schematic diagram of the control system of the continuous miner.

[0024] 1-upper level tunnel, 2-lower level tunnel, 3-coal mining device, 4-slurry (coal) blocking robot, 5-pushing mechanism, 6-synchronous winch, 7-guide pulley, 8-front pressure column, 9-rear pressure column, 10-pushing cylinder, 11-coal transport mechanism, 12-coal loading mechanism, 13-scraper conveyor, 14-filling body, 15-side cutting eye, 16-mixed slurry pipeline, 17-coal gangue belt conveyor. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples.

[0026] Example:

[0027] A backfill mining method for a steeply inclined coal seam comprises the following steps:

[0028] (1) Excavation and transportation tunnel, return air tunnel and cut: Excavation and transportation tunnel (lower level tunnel 2) and return air tunnel (upper level tunnel 1) are constructed according to the longwall working face system. A gangue belt conveyor 17 and a mixed slurry pipeline 16 are arranged at the upper return air tunnel, and a raw coal scraper conveyor 13 is arranged at the lower transport tunnel. At the designed cut position, a pseudo-inclined side cut 15 with a pseudo-inclination angle of no more than 45° is opened by a steeply inclined continuous miner with its own temporary support as a permanent ventilation pedestrian passage for this working face.

[0029] (2) Then, a steeply inclined coal seam with a temporary support type continuous mining machine is used to mine a pseudo-inclined branch tunnel Z1 with a width of 3-8m at a distance of 3-8m from the side cutting eye. The steeply inclined coal seam with a temporary support type continuous mining machine includes a coal mining device 3, a coal loading mechanism 12, a coal transportation mechanism 11, a pushing mechanism 5 and a pipe and cable wind tube support and moving device. The coal mining device 3 is a cutting head driven by a hydraulic motor; the coal loading mechanism is a crab claw loader 12 driven by a motor; the coal transportation mechanism is a scraper conveyor 11 driven by a motor; the coal mining device 3 is connected to the pushing mechanism, and the pushing mechanism 5 includes a front base and a rear base. The front base and the rear base are connected by a pushing oil cylinder 10. Front pressure columns 8 are provided on both sides of the front base, and rear pressure columns 9 are provided on both sides of the rear base. The cable wind tube support and moving device consists of a synchronous winch 6, a guide pulley 7 and a wire rope. The guide pulley 7 is arranged on the front base and is connected to the synchronous winch arranged in the lower level tunnel through a wire rope. The continuous miner also includes a motor and an oil pump that provide hydraulic energy for the entire machine; the remote control of the continuous miner can control all functions.

[0030] During coal mining, the continuous miner is assembled at the pre-cutting position in the lower drift. The front pressure column 8 is lowered to a certain height, and the push cylinder 10 pushes the coal mining section 3 forward to cut the coal. Simultaneously, the coal loading mechanism 12 and the coal transport mechanism 11 are activated. When the maximum stroke L of the push cylinder 10 is reached, the coal cutting is stopped, and the front pressure column 8 is raised as temporary support. Under the cover of this temporary support, the roof is anchored. After the support is completed, the rear pressure column 9 is lowered and the push cylinder 10 is retracted, causing the rear pressure column 9 to move upward a distance L. Simultaneously, the synchronous winch 6 is activated to move the wire rope upward the same distance L, and the next coal cutting cycle begins. The timing of support is selected according to the roof conditions and can be in front of or behind the continuous miner. If the roof is solid and no support is required, the work can be controlled from the lower drift control room, achieving unmanned operation at the working face. After mining a branch lane, the continuous miner is retracted from top to bottom. Only the rear pressure column 9 and the push cylinder 10 are used to move the entire machine downward. This is done by lowering the rear pressure column 9 and retracting the push cylinder 10, allowing the steeply inclined, self-supporting continuous miner to retract a distance L while simultaneously clearing the loose coal. Repeat this process until the continuous miner returns to the lower lane. A winch is then used to pull the miner to the next location for mining. Branch lanes Z3, Z4, and Z5 are mined sequentially, leaving several coal pillars, such as M2, M3, and M4, in place.

[0031] (3) A gangue delivery hole is constructed from the ground to the underground, and the gangue is transported to the upper opening of the Z1 branch tunnel by the gangue belt conveyor 17; at the same time, a ground slurry station is constructed to mix fly ash, cement and other additives into a mixed slurry, which is then transported to the upper opening of the Z1 branch tunnel through the mixed slurry pipeline 16.

[0032] (4) The slurry blocking robot 4 with patent application number CN201921954702.8 is used to seal the lower mouth of branch tunnel Z1. The slurry blocking robot 4 has a slurry pressure detection function and can alarm when the pressure value reaches the robot's slurry blocking rated value.

[0033] (5) Gangue and mixed slurry are added at the same time at the top of branch tunnel Z1. The gangue and mixed slurry are mixed evenly while rolling down. The pressure of the slurry on the slurry blocking robot 4 is monitored at any time. When the alarm is triggered, filling is stopped. Filling can be continued when the pressure drops below the set pressure.

[0034] (6) After filling Z1, move the slurry blocking robot 4 to the lower opening of Z2 and fill Z2, Z3, Z4, etc. in sequence according to steps 4 and 5.

[0035] (7) When the filling strength of the branch tunnel reaches the design value (different mine pressures are closely related to the surrounding rock strength), the coal pillars M1, M2, M3, etc. are mined using a steeply inclined continuous mining machine with its own temporary support.

[0036] (8) Then fill M1, M2, M3, etc. according to the steps. At this time, only the lower end 3-8m can be filled to meet the requirements of retaining lanes.

Claims

1. A backfill mining method for steeply inclined coal seams, characterized by: It includes the following steps: Step A: Excavation of transport tunnels, return air tunnels, and cuts: Excavation of transport tunnels and return air tunnels follows the longwall working face system. Gangue belt conveyors and mixed slurry pipelines are arranged in the upper return air tunnel, and raw coal scraper conveyors are arranged in the lower transport tunnel. A steeply inclined continuous miner with its own temporary support is used to create a pseudo-inclined side cut at a pseudo-inclination angle of no more than 45° at the designed cut location, serving as a permanent ventilation pedestrian passage for this working face. Step B: Then use a steeply inclined continuous miner with its own temporary support to mine a pseudo-inclined branch tunnel Z1 with a width of 3-8m at a distance of 3-8m from the side cut. After mining, leave a coal pillar M1 with a width of 3-8m to mine Z2, and then mine branch tunnels Z3, Z4, Z5, etc. in sequence, while leaving several coal pillars M2, M3, and M4. Step C: construct a gangue delivery hole from the surface to the underground, and transport the gangue to the upper opening of the Z1 branch tunnel via the gangue belt conveyor 17; at the same time, build a ground slurry station to mix fly ash, cement and other additives into a mixed slurry, and transport it to the upper opening of the Z1 branch tunnel via the mixed slurry pipeline 16; Step D: Use the slurry blocking robot 4 to block the lower opening of the branch tunnel Z1. The slurry blocking robot has a slurry pressure detection function and can alarm when the pressure value reaches the robot's slurry blocking rated value; Step E: Gangue and mixed slurry are added simultaneously at the top of branch tunnel Z1. The gangue and mixed slurry are mixed evenly while rolling down. The pressure of the slurry on the slurry blocking robot 4 is monitored at all times. When an alarm is triggered, filling is stopped and can be continued when the pressure drops below the set pressure. Step F: After filling Z1, move the slurry blocking robot 4 to the lower opening of Z2, and fill Z2, Z3, and Z4 in sequence according to steps 4 and 5; Step G: After the strength of the branch tunnel filling body reaches the designed strength, use the steeply inclined continuous miner with its own temporary support to mine the coal pillars M1, M2, and M3; then fill M1, M2, M3, etc. according to the steps. At this time, only the lower 3-8m can be filled to meet the requirements of retaining the tunnel.

2. The backfill mining method for a steeply inclined coal seam according to claim 1, wherein: The continuous mining machine includes a coal mining device, a coal loading mechanism, a coal transporting mechanism, a pushing mechanism and a pipe and cable wind cylinder supporting and moving device, the coal mining device is a cutting head driven by a hydraulic motor; the coal loading mechanism is a crab claw loader driven by a motor; the coal transporting mechanism is a scraper conveyor driven by a motor, the coal mining device is connected to the pushing mechanism, and the pushing mechanism includes a front base and a rear base, and the front base and the rear base are connected by a pushing oil cylinder, front pressure columns are provided on both sides of the front base, and rear pressure columns are provided on both sides of the rear base; the pipe and cable wind cylinder supporting and moving device is composed of a synchronous winch, a guide pulley and a wire rope, and the guide pulley is provided on the front base and is connected to the synchronous winch provided in the lower level tunnel through a wire rope. The continuous mining machine also includes a motor and an oil pump that provide hydraulic energy for the whole machine; the hydraulic motor, pushing oil cylinder, synchronous winch, the front pressure column oil cylinder that controls the front pressure column and the rear pressure column oil cylinder that controls the rear pressure column are connected to a control system, and the control system is integrated in the remote control.

3. The backfill mining method for a steeply inclined coal seam according to claim 2, characterized in that: The method of using the steeply inclined continuous mining machine with temporary support is as follows: the two front pressure columns are lowered to a certain height, and the coal mining part is pushed forward by the push cylinder to cut coal. When the maximum stroke L of the push cylinder is reached, the coal cutting is stopped, and the front pressure column is raised as a temporary support. Under the cover of the temporary support, anchor support is carried out, and then the rear pressure column is lowered and the push jack is retracted. The rear pressure column is moved up a distance L and then raised. At the same time, the synchronous winch is started to move the wire rope up the same distance L to enter the next coal cutting cycle; the support time is selected according to the roof situation , it can be in front of the continuous miner or behind the continuous miner; if the roof is hard and does not need support, it can be controlled in the control room of the lower level tunnel to realize unmanned working face; after mining a branch tunnel, exit the steeply inclined continuous miner with temporary support from top to bottom. At this time, only the rear pressure column and the push cylinder are used to move the whole machine downward. The operation method is to lower the rear pressure column, retract the push cylinder, and make the continuous miner retreat a distance L, while cleaning the floating coal; repeat the above operation to make the continuous miner retreat to the lower level tunnel for mining the next branch tunnel.

4. A backfill mining method for a steeply inclined coal seam according to any one of claims 1, 2, and 3, characterized in that: This mining method is also suitable for mining three-down coal in coal seams with inclinations between 12° and 45°.

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