Underground mining, selecting and filling integrated filling mining process

Abstract

The invention relates to a coal mine filling mining process, in particular to an underground mining, selecting and filling integrated filling mining process. The process comprises a working face mining process and working parameters of a coal mining machine; an underground gangue discharge process, a jigging process and a product dehydration process; and the filling process comprises the steps of building block processing, storage, transportation and masonry, and grouting secondary filling is conducted on a roadway and masonry gaps after working face stoping is completed. According to the underground mining, selecting and filling integrated filling mining process, coal can be completely washed, gangue is directly filled underground, up-down back-and-forth transportation of a gangue well is avoided, and the effective productivity of a mine is improved; the building blocks are filled for roof contact, the initial supporting force is large, roof deformation and sinking are avoided, ground surface sinking is avoided, and ground surface structures are protected.

Description

Technical Field

[0001] The invention relates to a coal mine filling mining process, in particular to an underground coal mine mining, dressing and filling integrated filling mining process. Background Art

[0002] There are some problems with the existing integrated mining, dressing and filling technology in underground coal mines. First, the gangue discharge is insufficient, and only lumps of coal can be washed for gangue discharge, and some gangue remains in the raw coal, which increases the ineffective lifting of the mine and reduces the effective production capacity of the mine; second, the existing filling method is not solid and cannot completely connect the roof. The filling material is compressible or compressed and deformed, and the supporting force is lagging. The roof cannot be supported in time in the initial stage, and the roof will sink. After a certain period of time, it will spread to the surface, causing the surface to sink. Summary of the Invention

[0003] The purpose of the present invention is to propose a coal mine filling mining process to address the shortcomings of the existing technology. The present invention conducts deep gangue discharge of coal underground, discharges all gangue larger than 0.5 mm, makes blocks underground, and transports them to the mining face for filling. The blocks are well connected to the top and are incompressible, so they can support the top plate and prevent it from sinking.

[0004] The technical solution adopted by the present invention is:

[0005] An underground mining, dressing and filling integrated mining process comprises the following steps:

[0006] a. Use double rocker drum shearer for forward mining, mining the entire height with one cut, cutting at an angle, with a cutting depth of 0.6-1.0m;

[0007] b. Set up a gangue discharge system underground: After screening and crushing, all or part of the raw coal enters the jig for gangue discharge, and the gangue is transported to the gangue bin; after the clean coal is classified and dehydrated, coal with a diameter greater than 0.5mm enters the main transportation system, and coal with a water content less than 0.5mm is concentrated and classified. Coal with a diameter greater than 0.15mm is dehydrated and enters the main transportation system, and coal with a water content less than 0.15mm enters the concentrator. After the underflow is dehydrated, it enters the main transportation system, and the overflow is circulated to the jig;

[0008] c. Making filling blocks underground: Mix gangue, cement and water in proportion, inject into the mold, vibrate, pressurize and form, and then cure to obtain blocks;

[0009] d. The blocks are transported to the working surface and laid using the lifting device and manipulator of the filling support tail beam. The top gap between the blocks after assembly is ≤100mm, and wooden wedges are used for top support;

[0010] e. After the working face is mined, grouting is injected into the tunnel to fill the gaps between the blocks and the roof.

[0011] Preferably, in step b, when the mine depth is less than 200 m and there is a coal preparation plant on the ground, the coal water with a particle size less than 0.15 mm is concentrated and transported to the ground coal preparation plant for treatment.

[0012] Preferably, in step c, the length of the building block is consistent with the width of the bracket, the width of the building block is consistent with the cutting depth of the coal mining machine, and the height of the building block can be 500mm, 300mm and 200mm according to the height of the bracket.

[0013] Preferably, in step c, the gangue or construction waste is transported to the underground block processing system through a ground feeding well.

[0014] Preferably, in step e, the grouting pressure is 0.5-1.0 MPa, and the grouting pipe is provided with a plurality of discharge holes with a hole spacing of ≤10 m.

[0015] The present invention has the following beneficial effects:

[0016] The underground integrated mining process of the present invention can wash all the coal and discharge all the gangue with a diameter of 0.5 mm or above, thereby increasing the effective lifting of the mine, avoiding the up and down transportation of gangue in the mine, and improving the effective production capacity of the mine; the filling and roof connection has a large initial support force, which can completely drag the roof to avoid deformation and sinking of the roof, thereby avoiding surface subsidence and protecting surface structures; the roof is supported and does not collapse, which solves the problem of mine pressure on the working face and plays a safety protection role in the mining of coal seams with impact ground pressure; the mining, dressing and filling process is continuous, which is convenient for underground management. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a system for washing and discharging all raw coal in an underground integrated mining, dressing and filling mining process according to the present invention;

[0018] Figure 2 This is a schematic diagram of a partial washing and gangue removal system for raw coal in an underground integrated mining, dressing and filling mining process of the present invention;

[0019] Figure 3 This is a schematic diagram of a ground treatment system for all raw coal washing and tailings of coal slime in an underground integrated mining, dressing and filling mining process of the present invention;

[0020] Figure 4 This is a schematic diagram of a block manufacturing system for an underground mining, dressing and filling integrated filling mining process according to the present invention.

[0021] In the figure: 1. Raw coal grading screen; 2. Crusher; 3. Jig; 4. Bucket elevator; 5. Clean coal grading and dewatering screen; 6. Concentrating cyclone (or sedimentation tank); 7. High-frequency screen; 8. Concentrator; 9. High-frequency screen (or filter press); 10. Gangue bin; 11. Ground feeding pit; 12. Cement tank; 13. Belt feeder; 14. Screw feeder; 15. Mixer; 16. Block forming equipment. DETAILED DESCRIPTION

[0022] An underground mining, dressing and filling integrated mining process comprises the following steps:

[0023] The working face uses a double-arm drum shearer, capable of mining the entire coal face in one cut and capable of cutting at an angle. Mining proceeds forward, with the shearer automatically cutting into lanes, facilitating the retention of lanes along the goaf. The shearer's cutting depth is 0.8m. Coal is transported to the waste chamber via a scraper conveyor at the working face, a retractable belt conveyor in the transport chute, and a belt conveyor in the mining area transport lane.

[0024] The raw coal is screened by the raw coal screen, and the lumps are crushed. All of them enter the jig for gangue discharge. The discharged gangue enters the gangue bin and is used to make filling blocks. The clean coal is graded and dehydrated by the clean coal grading and dewatering screen. Coal with a diameter larger than 0.5mm enters the mine's main transportation system, and coal with a diameter smaller than 0.5mm is concentrated and graded. Coal with a diameter larger than 0.15mm enters the high-frequency screen for dehydration. The high-frequency screened top product enters the main transportation system, and the undersize product and the concentrated and graded coal with a diameter smaller than 0.15mm enter the concentrator. The underflow of the concentrator enters the high-frequency screen or filter press for dehydration. The oversize product or filter cake enters the main transportation system, and the undersize water and the overflow of the concentrator enter the jig for recycling.

[0025] Depending on the actual situation such as the balance between on-site coal production and gangue consumption, the raw coal can be fully or partially washed.

[0026] If the mine depth is less than 200m and there is a coal preparation plant on the ground, the fine coal slime can be concentrated and directly discharged to the ground coal preparation plant for treatment, which can simplify the underground system.

[0027] An automatic feeding device is installed at the lower mouth of the gangue bin, an electronic weighing scale is installed on the belt conveyor to transport the gangue to the mixer, and a screw feeder is installed between the cement tank and the mixer. Gangue, cement and water are automatically fed in a fixed proportion, mixed evenly in the mixer, and the slurry is added to the block mold. There are three sizes of blocks: 1500mm×800mm×500mm, 1500mm×800mm×300mm and 1500mm×800mm×200mm. After vibration and compaction, they are placed in the prefabricated parts tunnel for curing. After 3 days, they are demoulded and stacked in the finished product tunnel. After 7 days when the strength meets the requirements, they are transported to the filling surface for filling.

[0028] According to the actual situation, if there is waste material such as gangue on the ground that needs to be processed, a feeding well can be drilled to put the ground gangue, construction waste, etc. into the block processing chamber, and the gangue, ground waste, cement, water, etc. are made into blocks according to a certain ratio.

[0029] The blocks are transported to the auxiliary transport entrance of the working face using a flatbed truck. A monorail crane is used to transport the blocks to the working face. A tail beam (approximately 2 meters) is set behind the filling support. A guard plate is added to the end of the tail beam, and a lifting device is installed on the tail beam. The blocks are transported to the masonry position and then laid using the manipulator on the support. Thick blocks are used at the bottom and thin blocks are used at the top. The gap between the top and bottom does not exceed 100mm. To ensure the initial support force, wooden wedges are used to support the top of the blocks.

[0030] After the working face is mined, the tunnel is grout-filled. The filling system includes slurry mixing equipment, grouting pumps, and pipelines. A filling pipe is installed at the top of the tunnel, with multiple discharge holes below. Both ends of the tunnel are sealed and grouting is performed. The slurry fills the tunnel and the gaps between the blocks and the roof.

[0031] Implementation Method 1

[0032] A mine has a production capacity of 1.5 million tons per year. The average thickness of the coal seam is about 2.8 meters, and the coal seam is nearly horizontal. The coal seam is buried at a depth of about 300 meters. Coal quality testing shows that the gangue content is about 20%. In order to increase effective production capacity, an integrated underground mining, dressing and filling mining process is adopted, leaving the gangue underground. Within the mine field, there is a village covered area with an area of ​​about 1 km 2 , backfill mining is carried out in this overburdened area, which not only recovers the village coal pillar resources, but also allows the gangue to be filled without lifting the well. The specific steps are as follows:

[0033] The working face uses a double-arm drum shearer, capable of mining the entire coal face in one cut and capable of cutting at an angle. Mining proceeds forward, with the shearer automatically cutting into lanes, facilitating the retention of lanes along the goaf. The working face is 70m long, with three cuts per day. The shearer cuts to a depth of 0.8m, and the support is 1.5m wide. Coal is transported to the waste chamber via the working face's scraper conveyor, transport chute belt conveyor, and mining area belt conveyor.

[0034] like Figure 1 and 2 The raw coal is screened by the raw coal grading screen 1, and the lumps are crushed by the crusher 2. All of them enter the jig 3 for gangue discharge. The gangue is lifted by the bucket elevator 4 and enters the gangue bin 10 for making blocks. The clean coal is graded and dehydrated by the clean coal grading and dewatering screen 5. Coal with a diameter greater than 0.5mm enters the mine's main transportation system. Coal with a diameter less than 0.5mm is concentrated and graded by the concentrating cyclone (or sedimentation tank) 6. Coal with a diameter greater than 0.15mm enters the high-frequency screen 7 for dewatering. The top product of the high-frequency screen enters the main transportation system, and the undersize product and the concentrated and graded coal with a diameter less than 0.15mm enter the concentrator 8. The underflow of the concentrator enters the high-frequency screen (or filter press) 9 for dewatering. The top product (or filter cake) enters the main transportation system. The underflow of the high-frequency screen (or filter press) 9 and the overflow of the concentrator enter the jig 3 for recycling.

[0035] like Figure 4An automatic feeding device is installed at the lower mouth of the gangue bin 10, and an electronic weighing scale is installed on the belt feeder 13 to transport the gangue to the mixer 15. A screw feeder 14 is installed between the cement storage tank 12 and the mixer 15. Gangue, cement and water are automatically fed in a fixed proportion, and the mixer mixes them evenly. The slurry is added to the block mold. There are two sizes of blocks, 1500mm×800mm×500mm and 1500mm×800mm×300mm. After being vibrated and compacted by the block forming equipment 16, they are placed in the prefabricated parts tunnel for curing. After 3 days, they are demoulded and stacked in the finished product tunnel. After 7 days, when the strength meets the requirements, they are transported to the filling surface for filling.

[0036] The blocks were transported to the auxiliary transport entrance of the working face using a flatbed truck. A monorail was used to hoist the blocks to the working face. A tail beam (approximately 2 meters) was set up behind the filling support. A guard plate was added to the end of the tail beam. A lifting device was installed on the tail beam to transport the blocks to the laying position. The blocks were then laid using the manipulator on the support. Five 500mm thick blocks were used for the lower part of the block, and 300mm thick blocks were used for the upper part. To ensure initial support, wooden wedges were used to support the upper part of the blocks.

[0037] After the working face is mined, the tunnel is grout-filled. The filling system includes slurry mixing equipment, grouting pumps, and pipelines. A filling pipe is installed at the top of the tunnel, with multiple discharge holes below. Both ends of the tunnel are sealed and grouting is performed. The slurry fills the tunnel and the gaps between the blocks and the roof.

[0038] The embedded grouting pipe is 108×3 steel pipe, the grouting pressure is 0.5MPa to 1.0MPa, and the spacing between discharge holes is 10m.

[0039] By adopting the integrated mining, dressing and filling mining process of this invention, all the coal can be washed, the gangue can be discharged to the maximum extent, the effective lifting of the mine is increased, the up and down transportation of gangue is avoided, and the effective production capacity of the mine is improved; the filling and roof connection have a large initial support force, which can completely drag the roof to avoid deformation and sinking of the roof, thereby avoiding surface subsidence and protecting surface structures; the roof is supported and does not collapse, which solves the problem of mine pressure on the working face and plays a safety protection role in the mining of coal seams with impact ground pressure; the mining, dressing and filling process is continuous, which is convenient for underground management.

[0040] Implementation Method 2

[0041] A mine has a production capacity of 1.5 million tons per year and houses a heavy medium coal preparation plant. The coal seam has an average thickness of approximately 2.7 meters and is nearly horizontal, with a depth of approximately 160 meters. The coal is high-quality coking coal with a gangue content of approximately 25%. The mine is located on the edge of an urban area and is surrounded by numerous surface buildings. The presence of coal pillars would affect the mine's service life. To improve coal resource recovery, an underground integrated mining, dressing, and filling process was implemented. The specific steps are as follows:

[0042] The working face uses a double-arm drum shearer, capable of mining the entire coal face in one cut and capable of cutting at an angle. Mining proceeds forward, with the shearer automatically cutting into lanes, facilitating the retention of lanes along the goaf. The shearer's cutting depth is 0.8m. Coal is transported to the waste chamber via a scraper conveyor at the working face, a retractable belt conveyor in the transport chute, and a belt conveyor in the mining area transport lane.

[0043] like Figure 3 The raw coal is screened by the raw coal grading screen 1, and the lumps are crushed by the crusher 2. All of the coal enters the jig 3 for gangue removal. The gangue is then lifted by the bucket elevator 4 and enters the gangue bin 10 for use in building blocks. The clean coal is graded and dehydrated by the clean coal grading and dewatering screen 5. Coal with a particle size larger than 0.5mm enters the mine's main transportation system. Coal with a particle size smaller than 0.5mm is concentrated and graded by the concentrating cyclone (or sedimentation tank) 6. Coal with a particle size larger than 0.15mm enters the high-frequency screen 7 for dewatering. The top-grade coal from the high-frequency screen enters the main transportation system, while the undersize coal and the concentrated and graded coal with a particle size smaller than 0.15mm enter the concentrator 8. The underflow from the concentrator is pumped to the surface coal preparation plant for washing. The overflow from the concentrator enters the jig 3 for recycling.

[0044] like Figure 4 An automatic feeding device is installed at the lower mouth of the gangue bin 10, and an electronic weighing scale is installed on the belt feeder 13 to transport the gangue to the mixer 15. A screw feeder 14 is installed between the cement storage tank 12 and the mixer 15. Gangue, cement and water are automatically fed in a fixed proportion, and the mixer mixes them evenly. The slurry is added to the block mold. There are two sizes of blocks, 1500mm×800mm×500mm and 1500mm×800mm×200mm. After being vibrated and compacted by the block forming equipment 16, they are placed in the prefabricated parts tunnel for curing. After 3 days, they are demoulded and stacked in the finished product tunnel. After 7 days, when the strength reaches the requirements, they are transported to the filling surface for filling.

[0045] The blocks were transported to the auxiliary transport entrance of the working face using a flatbed truck. A monorail was used to hoist the blocks to the working face. A tail beam (approximately 2 meters) was set up behind the filling support. A guard plate was added to the end of the tail beam, and a lifting device was installed on the tail beam. The blocks were transported to the laying position and laid using the manipulator on the support. Five 500mm thick blocks were used for the lower part of the block, and 200mm thick blocks were used for the upper part. To ensure the initial support force, wooden wedges were used to support the upper part of the blocks.

[0046] After the working face is mined, the tunnel is grout-filled. The filling system includes slurry mixing equipment, grouting pumps, and pipelines. A filling pipe is installed at the top of the tunnel, with multiple discharge holes below. Both ends of the tunnel are sealed and grouting is performed. The slurry fills the tunnel and the gaps between the blocks and the roof.

[0047] The present invention has the following beneficial effects:

[0048] By adopting the integrated mining and dressing filling mining process of this invention, all the coal can be washed, the gangue can be discharged to the maximum extent, the effective lifting of the mine is increased, the up and down transportation of the gangue well is avoided, and the effective production capacity of the mine is improved; the filling and roof connection has a large initial support force, which can completely drag the roof to avoid deformation and sinking of the roof, thereby avoiding surface subsidence, protecting surface structures, releasing coal pillars, increasing the mine's recoverable reserves, and extending the mine's service life.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the structure of the present invention in any form. Any simple modification, equivalent change and modification of the above embodiment based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. An underground mining, dressing and filling integrated mining process, characterized in that: The following steps are involved: a. Use double rocker drum shearer for forward mining, mining the entire height with one cut, cutting at an angle, with a cutting depth of 0.6-1.0m; b. Set up a gangue discharge system underground: After screening and crushing, all or part of the raw coal enters the jig for gangue discharge, and the gangue is transported to the gangue bin; after the clean coal is classified and dehydrated, coal with a diameter greater than 0.5mm enters the main transportation system, and coal with a water content less than 0.5mm is concentrated and classified. Coal with a diameter greater than 0.15mm is dehydrated and enters the main transportation system, and coal with a water content less than 0.15mm enters the concentrator. After the underflow is dehydrated, it enters the main transportation system, and the overflow is circulated to the jig; c. Making filling blocks underground: Mix gangue, cement and water in proportion, inject into the mold, vibrate, pressurize and form, and then cure to obtain blocks; d. The blocks are transported to the working surface and laid using the lifting device and manipulator of the filling support tail beam. The top gap between the blocks after assembly is ≤100mm, and wooden wedges are used for top support; e. After the working face is mined, grouting is injected into the tunnel to fill the gaps between the blocks and the roof.

2. The process according to claim 1, characterized in that: In step b, when the mine depth is less than 200m and there is a coal preparation plant on the ground, the coal water with a particle size less than 0.15mm is concentrated and transported to the ground coal preparation plant for treatment.

3. The process according to claim 1, characterized in that: In step c, the length of the block is consistent with the width of the bracket, the width of the block is consistent with the cutting depth of the coal mining machine, and the height of the block can be 500mm, 300mm and 200mm according to the height of the bracket.

4. The process according to claim 1, wherein: In step c, the gangue or construction waste is transported to the underground block processing system through the ground feeding well.

5. The process according to claim 1, characterized in that: In step e, the grouting pressure is 0.5-1.0 MPa, and the grouting pipe is provided with multiple discharge holes with a hole spacing of ≤10m.

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