Mine water control and protection method for coal mining in arid area

Abstract

The invention belongs to the technical field of coal mining and mine water protection, and particularly relates to a mine water control and protection method for coal mining in an arid area. A traditional long-wall working face is divided into a plurality of mining wide strip combinations in the length direction of the working face, and each mining wide strip combination comprises a paste filling roadway and a dry type filling wide strip; the width of the paste filling roadway is small, and the paste material filling roadway has the characteristic of high strength and can provide enough support for the basic roof; then, on the premise that the basic roof is kept stable, the wide strip is filled in a dry mode through the dry-type filling recovery technology; therefore, under the combination of the self-strength of the stope basic roof, the high-strength pasty fluid filling body main support and the large-area dry type filling body supplementary support, it can be guaranteed that the overlying stratum is stable, water-preserved coal mining is achieved, and meanwhile the water consumption of filling coal mining is reduced to the maximum extent. A filling hydraulic support can be omitted, the recovery cost is greatly saved, and the coal mining and filling environment can be improved.

Description

Technical Field

[0001] This invention belongs to the field of coal mining and mine water protection technology, specifically relating to methods for controlling and protecting mine water in coal mines in arid areas. Background Technology

[0002] In arid regions of Northwest China, such as Xinjiang, coal resources are abundant, but water resources are scarce and rainfall is rare. Coal mining damages the overlying strata, and the resulting fissures can disrupt underground aquifers and surface water systems. Furthermore, water from these aquifers and surface water systems entering the mined-out areas leads to water loss and mineralization, jeopardizing safe underground production. Backfill mining technology, by replacing underground coal with backfill materials, can reduce damage to the overlying strata and prevent fissures from connecting underground aquifers and surface water systems, thus achieving water-conserving mining. However, existing backfill mining technologies often use water as a carrier for transporting backfill materials, or the backfill materials themselves contain water, which is unsuitable for the water-scarce environment of Northwest China.

[0003] The arid Northwest region is rich in sand and gravel, making solid backfilling mining, a low-water-consumption technique, advantageous for water-conserving coal mining. However, the poor compaction and inadequate roof connection of solid backfilling result in insufficient control of surface subsidence and the generation of fissures in the overlying strata. If these fissures connect to aquifers or surface water systems, water-conserving coal mining will fail. Therefore, finding a way to achieve cost-effective water-conserving coal mining using dry backfilling technology with minimal water consumption is crucial to resolving the conflict between resource development and environmental protection in the arid Northwest region. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for controlling and protecting mine water in coal mines in arid areas, comprising the following steps:

[0005] S1: Transport roadway and return air roadway of the tunneling face; several mining wide strip combinations are planned from right to left along the length of the working face. Each mining wide strip combination includes a paste filling roadway on the left and a dry filling wide strip on the right; the width of the dry filling wide strip does not exceed the initial pressure step of the basic roof.

[0006] S2: Simultaneously excavate and fill two mining wide strips from right to left; excavate the paste filling tunnel from the working face transport roadway to the working face return airway; closely follow the paste filling tunnel, excavate the return air connecting tunnel in the dry filling wide strip, and at the same time, lag the excavation of the return air connecting tunnel to fill the paste filling tunnel with paste to form paste filling strip columns.

[0007] S3: Enter the dry filling wide strip by making a cut on the right side of the dry filling wide strip, and mine coal towards the return air roadway and the working face return air roadway until the coal mining and filling site is mined out. A protective coal pillar is left between the coal mining and filling site and the working face transport roadway. The sealing wall is constructed in the return air roadway between the protective coal pillar and the paste filling strip pillar.

[0008] S4: Carry out coal mining and dry backfilling work on the wide strip of dry backfilling; pile the dry backfilling material to the coal pillar of the roadway protection and the side of the paste backfilling pillar so that the coal mining and backfilling site and the working face transport roadway are connected.

[0009] S5: Based on S3 and S4, carry out mining and backfilling work on the next two mining wide strip combinations; at the same time, based on S2, construct the paste backfilling roadway and return air connecting roadway for the next two mining wide strip combinations; repeat this cycle until the entire working face is mined and backfilled.

[0010] Preferably, in step S1, the tunneling face transport roadway is driven to the designed starting position of the working face; the tunneling face return air roadway is driven, and the right end point of the working face return air roadway is located to the left of the right end point of the working face transport roadway, with the length of the interval being the width of a dry filling strip.

[0011] Preferably, in step S1, the distance between the working face return airway and the working face transport airway is 180-220m; the length of the working face is 1050m.

[0012] Preferably, in step S2, a continuous miner or tunneling machine is used for tunneling, and the excavated coal is loaded by a loader or scraper onto a belt conveyor in the working face transport roadway for transportation.

[0013] Preferably, in step S2, the ventilation path is: fresh air → working face transport roadway → return air connecting roadway → return air connecting roadway excavation face, becoming exhaust air → paste filling roadway → working face return air roadway.

[0014] Preferably, in step S3, the span of the coal mining and backfilling area in the front-to-back direction is not greater than the instability distance of the direct roof under the condition of fixed support at both ends.

[0015] Preferably, in steps S3 and S4, a continuous miner or a tunneling machine is used to mine the coal, and the mined coal is loaded by a loader or a scraper onto a belt conveyor in the working face transport roadway for transportation.

[0016] Preferably, in step S4, ground sand, gravel, building solid waste, and coal gangue are selected as dry backfill materials, transported by belt conveyor in the return airway of the working face, and then transported by transfer machine or shovel through the return airway to the coal mining and backfilling site for dry backfilling.

[0017] Preferably, in step S4, the dry backfilling operation is diagonally opposite to the coal mining operation, so that the dry backfill body is flush with the coal pillar of the roadway protection to form a connecting roadway between the coal mining and backfilling site and the working face transport roadway.

[0018] Preferably, in step S4, a retaining wall is erected on the dry filling body of the transport tunnel, and a single pillar is erected to support the retaining wall.

[0019] Preferably, in step S4, the ventilation path is: fresh air → working face transport roadway → cut-in → transport connecting roadway → coal mining and filling area, becoming exhaust air → return air connecting roadway → working face return air roadway.

[0020] Beneficial technical effects: 1. This invention addresses the need for water-conserving coal mining under water-scarce conditions in arid areas by proposing to divide the traditional longwall working face into several wide mining strip combinations along the length of the working face. Each wide mining strip combination includes a paste-filled roadway and a dry-filled wide strip. The paste-filled roadway has a small width and uses paste material for filling (water-consuming), which has high strength and can provide sufficient support for the basic roof. Then, under the premise of maintaining the stability of the basic roof, the dry-filled wide strip is used for mining. Thus, under the combination of the strength of the basic roof itself, the main support of high-strength paste filling body, and the supplementary support of large-area dry filling body, the stability of the overlying strata can be guaranteed to achieve water-conserving coal mining, while minimizing the water consumption of filling mining.

[0021] 2. This invention creatively proposes a construction process for paste-filled roadways and return air connecting roadways. The paste-filled roadway is excavated before filling, and the filling lags behind the excavation progress of the adjacent return air connecting roadway. This improves the stability of the roadway excavation and the working environment during the excavation of the return air connecting roadway. In this invention, when mining and dry-filling wide strips, a connecting transport roadway is maintained between the mining and filling area and the working face transport roadway. Combined with the return air connecting roadway, this forms a ventilation loop, greatly improving the construction environment of the mining and filling area and avoiding the poor environment problem of single-head ventilation in traditional roadway mining.

[0022] 3. The dry backfilling water-retaining coal mining method proposed in this invention can simultaneously carry out construction on multiple mining wide strip combinations, ensuring mining efficiency.

[0023] 4. Compared with traditional solid backfilling mining technology, the dry backfilling water-retaining coal mining method of the present invention can eliminate the backfilling hydraulic support with only a small increase in water consumption, greatly saving mining costs. Furthermore, compared with traditional longwall mining face roadway technology, the present invention can significantly improve mining efficiency and the mining and backfilling environment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the working surface arrangement of the present invention;

[0025] Figure 2 This is a schematic diagram of the construction of the paste filling tunnel and return air connection tunnel of the present invention;

[0026] Figure 3 This is a schematic diagram of the coal mining and backfilling site construction of the present invention;

[0027] Figure 4 This is a schematic diagram of the dry backfilling wide strip mining and backfilling process of the present invention;

[0028] Figure 5 for Figure 4 Enlarged schematic diagram of the coal mining and backfilling area;

[0029] Figure 6 This is a schematic diagram of the dry backfilling wide strip mining and backfilling cycle of the present invention;

[0030] In the diagram: 1-Return airway, 2-Transportation airway, 3-Working face return airway, 4-Working face transportation airway, 5-Paste filling airway; 6-Dry filling wide strip, 7-Paste filling pillar, 8-Return airway connecting roadway, 9-Sealing wall, 10-Road protection coal pillar, 11-Mining and filling area, 12-Enclosure plate, 13-Transportation connecting roadway, 14-Single support pillar, 15-Dry filling body, 16-Cutting face. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in conjunction with the accompanying drawings.

[0032] The method for controlling and protecting mine water in coal mines in arid areas proposed in this invention includes the following steps:

[0033] Step 1: As Figure 1 As shown, the working face transport roadway 4 is excavated from the main transport roadway 2 to the right to the designed starting position of the working face, and the working face return air roadway 3 is excavated from the return air roadway 1 to the right. The right end point of the working face return air roadway 3 is located to the left of the right end point of the working face transport roadway 4, and the length of the interval is the width of a dry filling wide strip 6. The width of the working face return air roadway 3 and the working face transport roadway 4 is 5.0m, and the height is the coal seam height of 4.0m. The distance between the working face return air roadway 3 and the working face transport roadway 4 is 180-220m, that is, the length of the dry filling wide strip 6 is 180-220m.

[0034] Determine the initial crushing step distance of the basic roof under the condition of fixed support at both ends; take a certain safety factor to determine the width of the dry filling wide strip 6; for example, if the initial crushing step distance of the basic roof under the condition of fixed support at both ends is 35m, then take the width of the dry filling wide strip 6 as 30m.

[0035] Along the length of the working face, from the designed starting position to the designed stopping position (from right to left), several wide mining strip combinations are planned sequentially. Each wide mining strip combination includes a paste filling roadway 5 on the left and a dry filling wide strip 6 on the right. The paste filling roadway 5 has a width of 5.0m and a height equal to the coal seam height of 4.0m. The length of the working face, i.e., from the designed starting position to the designed stopping position, is 1050m.

[0036] Step 2: As Figures 1-2As shown, from the designed starting position to the designed stopping position (from right to left), each mining and backfilling involves two or more mining wide strip combinations. This embodiment takes two as an example. From the working face transport roadway 4 to the working face return air roadway 3, the paste backfill roadway 5 is excavated to the working face return air roadway 3. The excavation is carried out by a continuous miner or a tunneling machine. The excavated coal is loaded by a loader or a scraper and transported out by a belt conveyor in the working face transport roadway 4.

[0037] Adjacent to the paste filling roadway 5, the return air connecting roadway 8 is excavated in the dry filling wide strip 6. At the same time, the excavation of the return air connecting roadway 8 is delayed to fill the paste filling roadway 5 with paste to form paste filling strip columns 7. The delay distance is 5.0-10.0m. The width of the return air connecting roadway 8 is 4.0m, and the height is the same as the coal seam height of 4.0m. The ventilation path is: fresh air → transport roadway 2 → working face transport roadway 4 → return air connecting roadway 8 → return air connecting roadway excavation face, becomes exhaust air → paste filling roadway 5 → working face return air roadway 3 → return air main roadway 1.

[0038] Step 3: As Figure 3 As shown, a cut 16 is made on the right side of the dry backfilling wide strip 6 to enter the dry backfilling wide strip 6 for coal mining. The width of the cut 16 is 4.0m. The coal mining equipment used is a continuous miner or a tunneling machine. The mined coal is loaded by a loader or a shovel and transported by a belt conveyor in the working face transport roadway 4. Coal mining proceeds in width towards the return air connecting roadway 8 and in length towards the working face return air roadway 3 until the coal mining and backfilling area 11 is reached. A protective coal pillar 10 is provided between the backfill site 11 and the working face transport roadway 4. The width of the protective coal pillar 10 is 5.0m. The return airway 8 between the protective coal pillar 10 and the paste filling strip pillar 7 is sealed by a sealing wall 9. The span of the coal mining and backfill site 11 in the front-back direction is not greater than the loss distance of the immediate roof under the condition of fixed support at both ends, that is, the initial pressure step distance of the immediate roof. In this embodiment, the span of the coal mining and backfill site 11 in the front-back direction is 10m.

[0039] Step 4: As Figures 4-5 As shown, coal mining and backfilling are carried out in the dry backfilling wide strip 6. Coal is mined using a continuous miner or a tunneling machine. The mined coal is loaded by a loader or a shovel and transported out by a belt conveyor in the working face transport roadway 4. Sand, gravel, solid waste from buildings, and coal gangue are selected from the ground as dry backfilling materials. They are transported by a belt conveyor in the working face return airway 3, and then transported by a transfer machine or a shovel through the return air connecting roadway 8 to the coal mining and backfilling site 11 for dry backfilling.

[0040] The dry backfilling operation is diagonally opposite to the coal mining operation. A gangue dumping machine is used to pile the transported dry backfilling material onto the side of the roadway support coal pillar 10 and the paste backfilling bar pillar 7, and to make the backfilling body 15 flush with the roadway support coal pillar 10, so that the coal mining and backfilling site 11 and the working face transport roadway 4 are connected by the transport roadway 13. In order to improve the stability of the transport roadway 13, a retaining plate 12 is installed on the dry backfilling body of the transport roadway 13, and a single pillar 14 is installed to support the retaining plate 12.

[0041] The ventilation path is as follows: fresh air → main transport roadway 2 → working face transport roadway 4 → cut 16 → transport connecting roadway 13 → coal mining and backfilling area 11, becoming exhaust air → return air connecting roadway 8 → working face return air roadway 3 → return air main roadway 1.

[0042] Step 5: As Figure 6 As shown, according to the third and fourth steps, the next two mining wide strip combinations are excavated and filled; at the same time, according to the second step, the paste filling tunnel 5 and return air connecting tunnel 8 of the next two mining wide strip combinations are constructed; this cycle continues until the entire working face is excavated and filled.

[0043] This invention is not limited to the preferred embodiments described above. Anyone can derive other methods in various forms under the guidance of this invention. Any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for controlling and protecting mine water in a coal mine in an arid region, characterized in that, The method comprises the following steps: S1: excavating the transportation roadway of the working face and the air return roadway of the working face; planning a plurality of mining wide strip combinations in sequence from right to left along the length direction of the working face, each mining wide strip combination comprising a paste filling roadway on the left side and a dry filling wide strip on the right side; the width of the dry filling wide strip is not more than the initial pressure step distance of the main roof; S2: simultaneously mining and filling two mining wide strip combinations from right to left each time; excavating the paste filling roadway from the transportation roadway of the working face to the air return roadway of the working face; excavating the air return connecting roadway in the dry filling wide strip close to the paste filling roadway, and simultaneously lagging behind the excavation of the air return connecting roadway to perform paste filling on the paste filling roadway to form a paste filling strip column; S3: cutting into the dry filling wide strip on the right side of the dry filling wide strip, and mining coal towards the air return connecting roadway and the air return roadway of the working face until the mining and filling field is mined out, leaving a roadway protection coal pillar between the mining and filling field and the transportation roadway of the working face, and constructing a partition wall in the air return connecting roadway between the roadway protection coal pillar and the paste filling strip column to block off; S4: performing coal mining and dry filling work on the dry filling wide strip; and piling up the dry filling material to the roadway protection coal pillar and the paste filling strip column side to keep the transportation connecting roadway connected between the mining and filling field and the transportation roadway of the working face; S5: performing mining, filling work on the next two mining wide strip combinations according to S3 and S4; and simultaneously performing construction on the paste filling roadway and the air return connecting roadway of the next two mining wide strip combinations according to S2; and repeating the above steps until the entire working face is mined and filled.

2. The arid zone coal mining well water control and protection method of claim 1, wherein, In step S1, the transportation roadway of the working face is excavated to the designed initial mining position of the working face; and the air return roadway of the working face is excavated, with the right end position of the air return roadway of the working face being located to the left of the right end position of the transportation roadway of the working face, and the interval length being the width of one dry filling wide strip.

3. The arid zone coal mining well water control and protection method of claim 1, wherein, In step S1, the interval between the air return roadway of the working face and the transportation roadway of the working face is 180-220 m; and the length of the working face is 1050 m.

4. The arid zone coal mining well water control and protection method of claim 2, wherein, In step S2, a continuous miner or a heading machine is used for excavation, and the excavated coal is loaded into the belt conveyor in the transportation roadway of the working face by a loader or a scraper for transportation; in steps S3 and S4, a continuous miner or a heading machine is used for coal mining, and the mined coal is loaded into the belt conveyor in the transportation roadway of the working face by a loader or a scraper for transportation.

5. The arid zone coal mining well water control and protection method of claim 4, wherein, In step S2, the ventilation path is: fresh air→the transportation roadway of the working face→the air return connecting roadway→the air return connecting roadway excavation face, which becomes exhaust air→the paste filling roadway→the air return roadway of the working face.

6. The arid zone coal mining well water control and conservation method as claimed in claim 1 wherein, In step S3, the span of the mining and filling field in the front and back directions is not greater than the instability step distance of the direct roof under the condition of two end fixed supports.

7. The arid zone coal mining well water control and conservation method as claimed in claim 1 wherein, In step S4, the sandstone, building solid waste and coal gangue on the ground are selected as the dry filling material, which is transported by a belt conveyor in the air return roadway of the working face, and then transported to the mining and filling field by a transfer machine or a scraper through the air return connecting roadway for dry filling.

8. The arid zone coal mining well water control and protection method of claim 7, wherein, In step S4, the dry filling work and the coal mining work are diagonally arranged, so that the dry filling body is flush with the roadway protection coal pillar to form the transportation connecting roadway between the mining and filling field and the transportation roadway of the working face.

9. The arid zone coal mining well water control and protection method of claim 8, wherein, In step S4, a surrounding baffle plate is arranged on the dry filling body side of the transportation connecting roadway, and a single support is arranged to support the surrounding baffle plate.

10. The arid zone coal mining well water control and protection method of claim 9, wherein, In step S4, the ventilation path is: fresh air → working face transport roadway → cut → transport connecting roadway → coal mining and filling field, becoming exhaust air → return air connecting roadway → working face return air roadway.

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