Mining technology of double-wing retreat type combined mining and filling recovery section coal pillar

Abstract

The purpose of this invention is to provide a mining process for recovering coal pillars in a double-wing retreating continuous mining and filling method, belonging to the field of coal mining technology. This invention achieves the complete recovery of coal pillar resources in the working face through three process steps: "access roadway excavation - tunnel mining - delayed filling". This avoids resource loss, especially of scarce and high-quality coal resources, due to the inability to recover coal pillars, and improves the resource recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of coal mining technology, specifically relating to a mining process for a double-wing retreating continuous mining and charging recovery section coal pillar. Background Technology

[0002] The "121" mining method in underground coal mines consists of one longwall mining face, two face roadways, and one coal pillar. A 20-30m wide coal pillar is left between adjacent longwall mining faces to isolate adjacent goaf areas, reduce the cumulative effect of nearby mining pressures, and maintain the stability of the face roadways. After the longwall mining face is fully mined, the coal resources in the coal pillar section cannot be recovered, resulting in a coal loss of approximately 10%-20% of the total coal resources of the longwall mining face. Summary of the Invention

[0003] The purpose of this invention is to provide a mining process for recovering coal pillars in a double-wing retreating continuous mining and charging manner, so as to achieve efficient and safe full recovery of coal pillar resources in the roadway of a longwall mining face, avoid the problem of resource loss, especially scarce and high-quality coal resources, due to the inability to recover coal pillars, and improve the resource recovery rate.

[0004] The present invention adopts the following technical solution:

[0005] A mining process for recovering coal pillars in a double-wing retreating continuous mining and charging section includes the following steps:

[0006] S1. According to the “121” mining method, the section coal pillar is reserved and a branch roadway is arranged in the central vertical transport roadway of the section coal pillar. The tunneling operation of the branch roadway is completed by the machine-mounted drilling frame continuous mining machine / tunneling and anchoring machine.

[0007] S2, double-wing herringbone-type mining chamber, retreat mining; backfilling operation is carried out in the middle of the roadway 20~30m behind the working face. The two side walls of the backfilling zone and the two side coal walls of the large cross-section roadway form two roadways, which are reserved for the transportation / return airway of the upper and lower working faces.

[0008] Furthermore, the width of the coal pillar in section S1 is 25-30m, the width of the branch roadway is 6-8m, and the length of the branch roadway is the same as the length of the working face.

[0009] Furthermore, in S2, the angle between the mining tunnel and the branch roadway is 45-60°, the height of the mining tunnel is equal to the height of the working face roadway, the length of the mining tunnel is 10-15m, and the width of the mining tunnel is equal to the width of the cutting head.

[0010] Furthermore, the tunneling operation of the branch tunnel described in S1 includes the following steps:

[0011] a. In the vertical transport roadway, use the machine-mounted drilling rig / tunneling and anchoring machine to complete one cut, with a cutting depth of 0.8-1.2m and a cut width equal to the width of the machine-mounted drilling rig / tunneling and anchoring machine's cutting head. At the same time, use the machine-mounted drilling rig to complete the top anchoring and side anchoring operations in this cycle. Repeat the above actions to complete 3-5 cycles, achieving a cut of 3-5m, and completing the grooving process.

[0012] b. Move the machine-mounted drilling rig / tunneling and anchoring machine to the other side of the branch roadway, repeat the above operation to complete the 3rd to 5th cuts, and complete the mining process;

[0013] c. Repeat the “cutting-stacking” process, advancing in a straight line to the end of the branch roadway, and complete the mining operation of the coal pillar within a 6-8m width of a branch roadway; during the mining operation, local ventilation fans are used for ventilation.

[0014] Furthermore, the retreating mining and backfilling operation described in S2 includes the following steps:

[0015] a. The mining chamber is arranged in a double-wing herringbone pattern, with the retaining wall support closely attached to the boundary line of the mining chamber in this round, to facilitate the coal dropping and collection operations of the machine-mounted drilling rig / tunneling and anchoring machine, and to move forward closely following the mining operation; the machine-mounted drilling rig / tunneling and anchoring machine is controlled by remote control to complete the mining of the left mining chamber and to complete the main anchor bolt or anchor cable support operations in the mining chamber; the mobile telescopic transfer machine completes continuous transportation and transfers the cut coal to the belt conveyor;

[0016] b. Remotely control the two-arm anchor drilling rig to move forward and complete the repair work on the newly exposed roadway side on the left and the remaining support work on the roof and sidewalls;

[0017] c. Repeat steps a and b to complete the "recovery-support" operation of the right-side mining tunnel; full-pressure ventilation is used in the branch roadway during the recovery of the mining tunnel;

[0018] d. After completing one mining chamber on each side of the branch roadway, use the support transport vehicle to move the 1-3 portal support supports that are furthest from the working face (i.e., the working face of the mining chamber) to the middle of the foremost roadway to complete the reinforcement support for the newly exposed roof.

[0019] e. Closely follow the progress of the working face and continuously construct the filling space in the roadway. After the retreat mining of the branch roadway has completed 20-30m advance (5-8 rows of mining chambers, 1 mining chamber on each side of the left and right sides of the row), start the filling operation until the sealed filling space in the roadway is filled.

[0020] f. Repeat steps a and e until all mining operations and tunnel filling operations are completed;

[0021] g. At this point, the recovery of the section coal pillar is completed, and through the backfilling operation in the roadway, two roadways are formed on each side of the backfill body, which are reserved for the transportation / return airway of the upper and lower working faces.

[0022] Furthermore, all support within the mining chamber is completed in two stages, achieving parallel "excavation-support" operations and improving tunneling and mining efficiency. The main support within the left / right mining chambers is provided by the onboard drill frame of the continuous mining machine / tunneling and anchoring machine, with support provided as excavation progresses. This ensures timely, proactive, and effective support for newly exposed roof sections, guaranteeing the stability of the main structure and preventing bending, delamination, collapse, or subsidence within a short period. The remaining support is subsequently supplemented by bolt drilling rigs on both the left and right sides.

[0023] Furthermore, the filling operation includes the following steps:

[0024] The original gangue is crushed into finished gangue with a particle size of less than 30mm using a crushing and sand making system;

[0025] The finished gangue is transported to the forced mixing system by a vertical elevator;

[0026] Mineral powder and fly ash are transported to the forced mixing system via screw conveyors, while water is pumped to the forced mixing system after being metered.

[0027] Finally, after being thoroughly mixed by a forced mixing system, the mixture is pumped to the branch roadway after mining through a pre-laid filling pipeline using a filling pump.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. The coal pillar resources in the working face section are fully recovered through three technological steps: "branch roadway excavation - mining tunnel recovery - delayed backfilling". This avoids the loss of coal resources, especially scarce and high-quality coal resources, due to the inability to recover coal pillar resources, thereby improving the resource recovery rate.

[0030] 2. The complete set of equipment for mining section coal pillar resources is a shortwall mining equipment. It can be applied not only to section coal pillar tunneling scenarios, but also to rapid tunneling scenarios in other coal roadways / semi-coal-rock roadways in the mine. At the same time, it can also be used in the continuous mining and filling scenarios of "three-under-coal" and shortwall mining scenarios of edge coal and irregular block resources in the mine, truly achieving "one machine for multiple uses" and maximizing the benefits of equipment investment.

[0031] 3. The onboard hydraulic drill arm of the continuous drilling machine / tunneling and anchoring machine provides faster support speed and higher support efficiency than a single drilling rig, while significantly reducing the labor intensity of workers.

[0032] 4. The mobile telescopic transfer unit provides continuous transportation, which has a greater transportation capacity compared to the intermittent transportation methods such as traditional shuttle cars and loaders. Attached Figure Description

[0033] Figure 1 Schematic diagram of the trenching process for branch tunnel excavation;

[0034] Figure 2 A schematic diagram of the branch tunnel excavation and mining process;

[0035] Figure 3 A schematic diagram showing the completion of the branch tunnel excavation;

[0036] Figure 4 This is a schematic diagram of the mining operation in the left-side mining tunnel;

[0037] Figure 5 This is a schematic diagram of the right-side mining tunnel.

[0038] Figure 6 This is a schematic diagram of the final state of a section of coal pillar after mining and backfilling.

[0039] Among them: 1-Airborne drilling rig continuous mining machine / tunneling and anchoring integrated machine; 2-Mobile telescopic transfer machine; 3-Belt conveyor; 4-Retaining wall support; 5-Two-arm anchor bolt drilling rig; 6-Portal support support complete set of equipment; 7-Backfill body; 8-Mining chamber; 9-Branch roadway; 10-Working face A; 11-Working face B; 12-Working face A opening; 13-Working face B opening; 14-Working face A roadway; 15-Working face B roadway; 16-Section coal pillar; 17-Main transport roadway; 18-Return airway; 19-Backfill body. Detailed Implementation

[0040] The invention will be further described with reference to the accompanying drawings.

[0041] This invention provides a mining process for recovering section coal pillars by combining a complete set of shortwall mining equipment with high-efficiency, high-roof-reach-rate backfilling. This mining process has a high degree of mechanization, high mining efficiency, flexible equipment movement, low initial investment, and quick results. It can effectively solve the problem of coal resource waste caused by the inability to recover 25-30m wide inter-face coal pillars left by the "121" mining method in underground coal mines. It is an efficient and safe method for recovering section coal pillars.

[0042] A mining process for recovering coal pillars in a double-wing retreating continuous mining and filling method includes roadway layout, mining equipment and its arrangement, coal pillar mining method, tunnel support technology, ventilation technology, and filling technology.

[0043] (1) Layout of alleyways

[0044] Following the "121" longwall mining method, a 25-30m wide coal pillar is reserved. A branch roadway 9 is arranged in the central vertical transport roadway 17 of the coal pillar 16, and its excavation is completed using a machine-mounted drilling rig / tunneling and anchoring machine 1. Then, a double-wing herringbone-shaped mining chamber 8 is arranged, with the angle between mining chamber 8 and branch roadway 9 generally at 45-60°, using a retreat mining method. 20-30m behind the working face, backfilling is carried out in the middle of the roadway. The two side walls of the backfilling zone and the two side coal walls of the large-section roadway form two roadways, reserved for use in the transport / return airway between the upper and lower working faces.

[0045] Branch roadway width: 6~8m; Angle between branch roadway and main roadway: 90°; Branch roadway length: equal to working face strike length; Angle between mining tunnel and branch roadway: 45-60°; Mining tunnel height: equal to working face roadway height; Mining tunnel length: 10-15m; Mining tunnel width: equal to equipment cutting head width, generally 3.3m; Filling body width: depends on coal seam occurrence and filling body strength, generally 6-10m.

[0046] (2) Downhole equipment configuration and layout

[0047] The working face utilizes a complete set of shortwall mechanized mining equipment for ore extraction, loading, and transportation. This equipment mainly includes: a machine-mounted drill-frame continuous mining machine / roadheader / anchor integrated machine 1; a mobile telescopic transfer conveyor 2; retaining wall supports 4; a two-arm bolt drilling rig 5 (with side repair function); a complete set of portal support equipment (portal support, support transport vehicle); and a belt conveyor 3. Support for the branch roadways is completed by the machine-mounted drill-frame continuous mining machine / roadheader / anchor integrated machine 1. The primary support for the first-pass mining chamber 8 is completed by the machine-mounted drill-frame continuous mining machine / roadheader / anchor integrated machine 1, while the delayed reinforcement support is completed by the two-arm bolt drilling rig 5 (with side repair function). The filling equipment includes: a crushing and sand making system, a forced twin-shaft mixing system, a coal mine-specific filling pump, and a filling pipeline system.

[0048] The tunneling operation of branch roadway 9 requires the following setup: 1 onboard drilling rig / mining machine / roadheader, 2 mobile telescopic transfer conveyor, and 3 belt conveyor. The onboard drilling rig / mining machine 1 cuts and loads coal, which is then transported to the roadway belt conveyor via the subsequent continuous transport system (mobile telescopic transfer conveyor).

[0049] The following equipment is required for the retreat mining operation of the double-wing retreating tunnel: 1. Onboard drilling rig continuous mining machine / tunneling and anchoring integrated machine, 2. Mobile telescopic transfer machine, 3. Belt conveyor, 4. Retaining wall support, 6. Complete set of portal support equipment (portal support + support transport vehicle), filling pipeline, 5. Two-arm anchor drilling rig (with side repair function).

[0050] (3) Section coal pillar mining process

[0051] Based on the "121" longwall mining method, a 25-30m wide coal pillar 16 is reserved. A branch roadway 9 is arranged in the central vertical mining area transport roadway 17 of the coal pillar 16, and its excavation is completed using a machine-mounted drilling rig / roadheader / anchor machine 1. Then, a double-wing herringbone-shaped mining tunnel 8 is arranged, with the angle between mining tunnel 8 and branch roadway 9 generally at 45-60°, using a retreat mining method. 20-30m behind the working face, backfilling is carried out in the middle of the roadway. The two side walls of the backfilling zone and the two side coal walls of the large-section roadway form two roadways, reserved for the transport / return airway between the upper and lower working faces. The main operation procedures are as follows:

[0052] a: In the vertical transport roadway 17, the machine-mounted drilling rig / tunneling and anchoring machine 1 completes one cut, with a cutting depth of 0.8-1.2m. The cut width is equal to the width of the cutting head of the machine-mounted drilling rig / tunneling and anchoring machine 1. At the same time, the machine-mounted drilling rig completes the top anchoring and side anchoring operations in this cycle. Repeat the above actions to complete 3-5 cycles, achieving a cut of 3-5m, and completing the grooving process;

[0053] b: Move the machine-mounted drilling rig / tunneling and anchoring machine 1 to the other side of the branch roadway 9, repeat the above operation to complete the 3rd to 5th cuts, and complete the mining process;

[0054] c: Repeat the "grooving-pillaring" process, maintaining a straight advance to the end of the branch roadway, completing the mining operation of a 16-coal pillar section within a 96-8m width of one branch roadway, specifically as follows: Figure 1 and Figure 2 As shown;

[0055] d: The mining chamber is arranged in a double-wing herringbone pattern, with the retaining wall support 4 closely attached to the boundary line of this mining chamber to facilitate the coal dropping and collection operations of the machine-mounted drilling rig / tunneling and anchoring machine 1, and to move forward closely following the mining operation. The machine-mounted drilling rig / tunneling and anchoring machine 1 is controlled by remote control to complete the mining of the left mining chamber and to complete the main anchor bolt (cable) support operation in the mining chamber 8. The mobile telescopic transfer machine 2 completes continuous transportation and transfers the cut coal to the belt conveyor 3.

[0056] e: Remotely operate the two-arm anchor drilling rig 5 to move forward to complete the repair work on the newly exposed sidewall on the left and the remaining support work on the top and sidewall;

[0057] f: Repeat steps de to complete the "recovery-support" operation of the right-side mining tunnel;

[0058] g: After completing one mining tunnel on each side of the branch roadway, use the support transport vehicle to move 1-3 portal support supports behind the working face (farthest from the working face of the mining tunnel) to the middle of the foremost roadway to complete the reinforcement support of the newly exposed roof.

[0059] h: Following the advancement of the working face, continuously construct the filling space in the roadway. After the retreat mining of the branch roadway has completed 20-30m advance (5-8 rows of mining chambers, 1 mining chamber on each side of the left and right sides of the row), start the filling operation until the sealed filling space in the roadway is filled.

[0060] i: Repeat steps dh until all mining operations and tunnel filling operations are completed;

[0061] j: At this point, the recovery of section coal pillar 16 is completed, and through the backfilling operation in the roadway, two roadways are formed on each side of the backfill body, which are reserved for the transportation / return airway of the upper and lower working faces.

[0062] (4) Mine support technology

[0063] All support within Mining Chamber 8 was completed in two phases, achieving parallel "excavation-support" operations and improving tunneling and mining efficiency. The main support within the left / right mining chambers was completed by the onboard drill frame of the machine-mounted drilling rig / tunneling and anchoring machine 1, with support provided as excavation progressed. This ensured timely, proactive, and effective support for newly exposed roof sections, guaranteeing the stability of the main structure and preventing bending, delamination, collapse, or subsidence within a short period. The remaining support was subsequently supplemented by bolt drilling rigs on both the left and right sides.

[0064] (5) Ventilation process

[0065] Local ventilation fans are used for side roadway mining; full-pressure ventilation can be used for side roadway mining during main tunnel mining.

[0066] (6) Filling process

[0067] The filling station mainly includes a crushing and sand making system, a forced mixing system, a filling pump, and a pipeline system. The crushing and sand making system crushes the raw gangue into finished gangue with a particle size of less than 30mm. The finished gangue is transported to the forced mixing system by a vertical elevator. Mineral powder, fly ash, etc. are transported to the forced mixing system by a screw conveyor. Water is pumped to the forced mixing system after being metered. Finally, the mixture is evenly mixed by the forced mixing system and then pumped to the branch roadway after mining through a pre-laid filling pipeline by the filling pump.

[0068] The specific construction process parameters are as follows: Single filling length: 20-30m. The strength and width of the filling body should be considered in a comprehensive manner based on the coal seam occurrence conditions, the width of the coal pillar in the section, the width of the working face transportation / return air roadway, etc. The width is generally 6~10m.

[0069] This invention can achieve the following objectives:

[0070] 1. By using the double-wing retreat continuous mining and charging technology, the problem of efficient and safe full recovery of coal pillar resources in the roadway section of the longwall fully mechanized mining face is solved, avoiding resource loss, especially of scarce and high-quality coal resources, due to the inability to recover coal pillars in the section, and improving the resource recovery rate.

[0071] 2. By adopting an airborne drilling rig / integrated drilling and anchoring machine, mechanized support operations for anchor bolts (cables) can be achieved, solving the problems of low mechanization, low support efficiency, and high labor intensity of handheld single hydraulic drilling rigs.

[0072] 3. The mobile telescopic transfer unit is selected for continuous transportation, which can achieve continuous large-angle and small-radius turns, and has a greater transportation capacity compared with traditional intermittent transportation methods such as shuttle cars and loaders.

Claims

1. A mining process of a double-wing retreat type combined mining and filling recovery section coal pillar, characterized in that: Includes the following steps: S1. According to the "121" mining method, the section coal pillar is reserved and a branch roadway (9) is arranged in the central vertical transport roadway (17) of the section coal pillar (16). The tunneling operation of the branch roadway (9) is completed by using the machine-mounted drilling frame continuous mining machine / tunneling and anchoring machine (1). S2, double-wing fishbone-type mining chamber (8), retreat mining; filling operation is carried out in the middle of the roadway 20~30m behind the tunneling face. The two walls of the filling zone and the two coal walls of the large cross-section roadway form two roadways, which are reserved for the transportation / return airway of the upper and lower working faces.

2. The mining process of claim 1, wherein: The width of the section coal pillar (16) mentioned in S1 is 25-30m, the width of the branch roadway (9) is 6-8m, and the length of the branch roadway (9) is the same as the length of the working face.

3. The mining process of claim 1, wherein: The angle between the mining tunnel (8) and the branch roadway (9) in S2 is 45-60°. The height of the mining tunnel (8) is equal to the height of the working face roadway. The length of the mining tunnel (8) is 10-15m. The width of the mining tunnel (8) is equal to the width of the cutting head.

4. The mining process of claim 1, wherein: The tunneling operation of the branch tunnel (9) described in S1 includes the following steps: a. Vertical transport roadway (17): Use the machine-mounted drilling rig / mining machine (1) to complete one cut, with a cutting depth of 0.8-1.2m. The cut width is equal to the cutting head width of the machine-mounted drilling rig / mining machine (1). At the same time, use the machine-mounted drilling rig to complete the top anchor and side anchor operations in this cycle. Repeat the above actions to complete 3-5 cycles, achieve a cut of 3-5m, and complete the grooving process. b. Move the machine-mounted drilling rig / mining machine (1) to the other side of the branch roadway (9), repeat the above operation to complete the 3rd to 5th cuts, and complete the mining process; c. Repeat the "cutting groove-collecting stack" process, keep advancing in a straight line to the end of the branch roadway, and complete the mining operation of the coal pillar (16) within a 6-8m width of a branch roadway (9); for mining operations, local ventilation fans are used for ventilation.

5. The mining process for a double-wing retreating continuous mining and charging recovery section coal pillar according to claim 1, characterized in that: The retreating mining and backfilling operation described in S2 includes the following steps: a. The double-wing fishbone-type arrangement of the mining chamber (8) is closely attached to the boundary line of the mining chamber in this round, so as to facilitate the coal dropping and coal collection operations of the machine-mounted drilling frame continuous mining machine / tunneling and anchoring machine (1) and move forward in close following the mining operation; the machine-mounted drilling frame continuous mining machine / tunneling and anchoring machine (1) is controlled by remote control to complete the mining of the left mining chamber and complete the main anchor bolt or anchor cable support operation in the mining chamber (8); the telescopic transfer machine (2) is moved to complete continuous transportation and transfer the cut coal to the belt conveyor (3); b. Remotely operate the two-arm anchor drilling rig (5) to move forward and complete the repair work on the newly exposed roadway side on the left side and the remaining support work on the top and side walls; c. Repeat steps a and b to complete the "recovery-support" operation of the right-side mining tunnel; full-pressure ventilation is used in the branch roadway during the recovery of the mining tunnel; d. After completing one mining chamber (8) on each side of the branch roadway (9), use the support transport vehicle to move the 1-3 portal support supports that are furthest from the working face of the mining chamber to the middle of the foremost roadway to complete the reinforcement support of the newly exposed roof. e. Closely follow the progress of the working face and continuously construct the filling space in the roadway. After the retreat mining tunnel of the branch roadway (9) has completed 20-30m of advance, start the filling operation until the sealed filling space in the roadway is filled. f. Repeat steps ae until all mining (8) operations and tunnel filling operations are completed; g. At this point, the recovery of the section coal pillar (16) is completed, and through the backfilling operation in the roadway, two roadways are formed on the left and right sides of the backfill body, which are left for the transportation / return air roadway of the upper and lower working faces.

6. The mining technology for a double-wing retreating continuous mining and charging recovery section coal pillar according to claim 5, characterized in that: All the support in the mining chamber (8) is completed in two stages to achieve parallel "drilling-support" operations and improve the efficiency of tunneling and mining. The main support in the left / right mining chamber is completed by the machine-mounted drilling frame of the machine-mounted drilling machine / drilling and anchoring machine (1). Support is provided as the drilling progresses, so as to achieve timely, proactive and effective support for the newly exposed roof, ensure the stability of the main body of the newly exposed roof, and prevent bending, delamination, collapse and sinking in a short period of time. The remaining support is completed by the left and right two-arm anchor drilling rigs (5) to make up for the delay.

7. The mining process for a double-wing retreating continuous mining and replenishment recovery section coal pillar according to claim 5, characterized in that: The filling operation includes the following steps: The original gangue is crushed into finished gangue with a particle size of less than 30mm using a crushing and sand making system; The finished gangue is transported to the forced mixing system by a vertical elevator; Mineral powder and fly ash are transported to the forced mixing system via screw conveyors, while water is pumped to the forced mixing system after being metered. Finally, after being thoroughly mixed by a forced mixing system, the mixture is pumped to the branch roadway after mining through a pre-laid filling pipeline using a filling pump.

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