A method for filling mining of near-vertical medium-thick and thick coal seams

Abstract

The application discloses a kind of near vertical medium-thick, thick coal seam filling mining method, it is related to coal mine filling mining technical field.In near vertical coal seam, the working face that is arranged downward is carried out, and according to the depth of coal seam, the working face is divided into multiple mining stages;In the top and bottom of each mining stage, horizontal direction goaf strip is respectively constructed, and goaf strip is filled with high water-cement ratio cementing material to form artificial false roof and artificial false bottom;From artificial false roof, the working face is downwardly mined until artificial false bottom, forming the goaf of mining stage;The goaf is completely filled with low water-cement ratio cementing material;Repeat the step to realize the filling mining of entire near vertical medium-thick, thick coal seam.This method can solve the mining problem of near vertical medium-thick, thick coal seam coal resources, release the stagnant coal resources caused by complex occurrence conditions, and can effectively reduce strata movement and surface deformation.

Description

A method for backfilling and mining near-vertical medium-thick and thick coal seams Technical Field

[0001] This invention relates to a method for backfilling and mining near-vertical medium-thick and thick coal seams, belonging to the field of coal mining technology. Background Technology

[0002] Mining near-vertical coal seams with dip angles ranging from 70° to 90° has always been a global challenge due to its complex geological conditions. However, the total resource volume is considerable, making it an important component for ensuring coal resource continuity and energy security. During near-vertical coal seam mining, the roof and floor are highly susceptible to movement and collapse towards the goaf under gravity. The coal seam itself becomes crucial for support; once mined, the weight of the overlying strata rapidly transfers to the working face below, causing significant stress concentration and easily triggering disasters such as coal wall spalling, instantaneous roof and floor closure, and rock bursts. Currently, for near-vertical extra-thick coal seams with a thickness greater than 30m, the main method is to use horizontal segmented fully mechanized mining with short-arm working faces and continuous drum mining machines for extraction. For near-vertical medium-thick and thick coal seams with a thickness greater than or equal to 3.5m, there is still no efficient and safe mechanized mining method, especially for deep coal resources, which are often stagnant due to their large dip angles. Summary of the Invention

[0003] Technical Issue: Addressing the shortcomings of existing technologies, this paper proposes a near-vertical medium-thick and thick coal seam backfilling mining method. This method utilizes a continuous coal mining machine to recover coal resources, and uses cemented backfill to control the roof and floor and treat goaf areas. It is convenient to use and safe to mine.

[0004] Technical Solution: To achieve the above technical objectives, this invention discloses a method for backfilling and mining near-vertical medium-thick and thick coal seams, the steps of which are as follows:

[0005] S1. Arrange downward working faces in near-vertical coal seams and divide the working faces into multiple mining stages according to the depth of the coal seam.

[0006] S2. Horizontal goaf strips are constructed at the top and bottom of each mining stage, and the goaf strips are filled with high water-cement ratio cementing material to form artificial false roof and artificial false bottom.

[0007] S3. The working face is mined downwards from the artificial false top until the artificial false bottom is reached, forming the goaf of the mining stage;

[0008] S4. Completely fill the goaf with low water-cement ratio cementitious materials;

[0009] S5. Repeat S2~S4 to achieve backfilling mining of the entire near-vertical medium-thick and thick coal seams.

[0010] Furthermore, during the process of mining downwards from the artificial false top to the artificial false bottom, a space for horizontally placing hydraulic supports is first mined out below the artificial false top. Then, hydraulic supports that can be suspended on the top and bottom plates of the mining stage are installed under the artificial false top. The hydraulic supports include a top structure that contacts the artificial false top. Devices that can be anchored into the top and bottom plates are provided on both sides of the top structure. The devices that are anchored into the top and bottom plates provide the top structure with the supporting force applied to the artificial false top.

[0011] Furthermore, during the mining process in the mining stage, the goaf strip is first completed by mining along the coal seam direction of the mining stage using a continuous coal mining machine. After the roof and floor plates are connected by anchor bolts arranged in the goaf strip at 1000mm×1000mm, a high water-ash ratio cementing material is injected into the goaf strip to construct an artificial false roof to support the overlying coal and rock mass. After the artificial false roof hardens, the continuous coal mining machine is used to mine along the underside of the hardened artificial false roof to form a space to accommodate hydraulic supports. Hydraulic supports are installed under the artificial false roof to protect the underside working space. At the same time, metal mesh and anchor bolts are used to support the roof and floor plates according to the characteristics of the coal seam.

[0012] Furthermore, after the mining stage is completed, a high water-cement ratio cementing material is filled at the bottom of the mining stage to construct an artificial false bottom. A low water-cement ratio cementing material is then filled into the goaf until it covers the hydraulic support. After the low water-cement ratio cementing material hardens, the hydraulic support is removed, and the space formed after the hydraulic support is removed is completely filled, thus completing the complete filling of the goaf between the artificial false top and the artificial false bottom.

[0013] Furthermore, when proceeding with the next mining stage, the artificial false bottom from the previous mining stage can be directly used as the artificial false top for the next mining stage.

[0014] Furthermore, during the hardening of the low water-ash ratio cementing material, the near-vertical medium-thick and thick coal seams of other strips or coal seam groups are mined and backfilled to achieve parallel operations between coal seam groups; the continuous mining machine mining and backfilling operations are repeated until the mining of all medium-thick coal seams in all strips is completed.

[0015] Furthermore, the ventilation system used in near-vertical medium-thick and thick coal seam backfilling mining includes a main shaft, an auxiliary shaft, and an air shaft. The main shaft and auxiliary shaft are used for air intake, while the air shaft is used for air return. The main shaft, auxiliary shaft, and air shaft are respectively connected to horizontally arranged haulage main roadways, track main roadways, and second-stage haulage gates. The haulage main roadway is connected to the second-stage haulage gates through stage connecting roadways and return air inclines. The track main roadway is connected to the second-stage haulage gates through track inclines. Coal chutes are constructed in the rock strata to connect the stage connecting roadways and the working face.

[0016] Furthermore, the ventilation route of the main shaft is: main shaft - transport roadway - stage connecting roadway - return air incline - second stage transport gate - ventilation shaft; the ventilation route of the auxiliary shaft is: auxiliary shaft - track roadway - track incline - working face - coal chute - stage connecting roadway - return air incline - second stage transport gate - ventilation shaft.

[0017] Furthermore, the material transport route is: auxiliary shaft - main track roadway - track incline - working face; the coal crushed by the continuous coal mining machine at the working face is transported to the coal chute via belt conveyor; the coal transport route is: working face - coal chute - stage connecting roadway - transport roadway - main shaft.

[0018] Beneficial Effects: Continuous mechanized backfilling mining technology, by dividing the coal seam into different mining stages and integrating fully mechanized mining machinery with backfilling processes, provides a solution for the safe and efficient development of near-vertical medium-thick and thick coal seams. Its core advantages lie in the efficient utilization of resources through mechanical cutting, which extracts almost all coal from the working face; the continuous mechanized mining process enables separate excavation and transportation of coal and rock, reducing the gangue content of raw coal and improving the quality of marketable coal; the exposed area of ​​the goaf is small and can be supported in a timely manner; the backfill effectively suppresses wall deformation and spalling, improving the overall stability of the mining area, effectively supporting the goaf, and inhibiting the movement and collapse of overlying strata, thereby significantly reducing the risk of high stress concentration and strong dynamic disasters such as rockbursts in deep mining. This invention has significant advantages in terms of technology, safety, and economic benefits, minimizing surface subsidence, protecting the surface ecology and infrastructure of the mining area, and achieving underground treatment of solid waste such as gangue, meeting the requirements of green mining. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the decoupling strand of the mining system used in near-vertical medium-thick and thick coal seam backfilling mining in an embodiment of the present invention.

[0020] Figure 2 is a side view of the downward feed of the continuous coal mining machine in an embodiment of the present invention.

[0021] Figure 3 is a top view of the coal mining face of the continuous coal mining machine in an embodiment of the present invention.

[0022] Figure 4 is a schematic diagram of the near-vertical medium-thick and thick coal seam filling mining process in the embodiment of the present invention; in the figure, (1) is a schematic diagram of the state of the coal seam when it is not mined, (2) is a schematic diagram of constructing the goaf strip and reinforcing it with anchor bolt metal mesh, (3) is a schematic diagram of constructing the artificial false roof in the mining stage, (4) is a schematic diagram of constructing the hydraulic support installation space under the artificial false roof, (5) is a schematic diagram of mining under the hydraulic support, (6) is a schematic diagram of completing a mining stage and constructing an artificial false bottom, (7) is a schematic diagram of completely filling the goaf area between the artificial false roof and the artificial false bottom, (8) is a schematic diagram of using the artificial false bottom of the previous mining stage as the artificial false roof of the current mining stage and installing hydraulic supports for mining, and (9) is a schematic diagram of completely filling the goaf area in the second mining stage.

[0023] Figure 5 is a schematic diagram of the anchor bolt-metal mesh laying arrangement during the mining stage in an embodiment of the present invention.

[0024] In the diagram, 1-Main shaft; 2-Auxiliary shaft; 3-Ventilation shaft; 4-Working face; 5-Coal chute; 6-Stage connecting roadway; 7-Main track roadway; 8-Main transport roadway; 9-Second stage transport gate; 10-Coal seam; 11-Goaf strip; 12-Anchor bolt; 13-High water-ash ratio cementing material; 14-Artificial false roof; 15-Hydraulic support; 16-Artificial false floor; 17-Goaf; 18-Low water-ash ratio cementing material; 19-Track incline; 20-Continuous mining machine; 21-Metal mesh; 22-Return air incline; 23-Belt conveyor. Detailed Implementation

[0025] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0026] This invention discloses a method for backfilling and mining near-vertical medium-thick and thick coal seams. Due to the special structure of vertical medium-thick and thick coal seams, the working face of this application is actually mined from top to bottom, which is equivalent to rotating the existing working face by 90° for mining. Therefore, the roof and the roof mentioned in this application actually refer to the rock strata on the left and right sides of the working face of the vertical coal seam being mined. In order to facilitate mining and support, this application divides the working face according to the horizontal height, and each division is called a mining stage.

[0027] The near-vertical medium-thick and thick coal seams are divided into different stages according to their height for mining. The mining system uses a continuous coal mining machine 20 to mine the coal resources downwards in each mining stage. In each mining stage, goaf strips 11 are constructed at the uppermost and lowermost layers and filled with high water-ash ratio cementing material 13 to form artificial false roofs 14 and artificial false floors 16. The previous artificial false floor serves as the artificial false roof 14 for the next mining stage. Hydraulic supports 15 are installed under the artificial false roof 14 to provide a safe working space. After the mining stage is completed, the goaf 17 of the current mining stage is filled with low water-ash ratio cementing material 18 to achieve control of the roof and floor of the near-vertical medium-thick and thick coal seams and goaf treatment.

[0028] The specific implementation steps are as follows:

[0029] In the initial mining stage of coal mining operations, the continuous coal mining machine 20 is used to mine along the strike of the coal seam 10. After the continuous coal mining machine 20 advances 200m~300m along the strike to complete the mining of the first coal seam, the first goaf strip 11 is formed. In the first goaf strip 11, anchor bolts 12 are arranged in 1000mm×1000mm to connect the top and bottom plates, as shown in Figure 5. High water-ash ratio cementing material 13 is injected into the first goaf strip 11 to construct an artificial false roof 14. The artificial false roof 14 supports the overlying coal and rock mass.

[0030] As shown in Figure 2, after the artificial false roof 14 is hardened, the continuous coal mining machine 20 is used to mine the coal resources in stages from top to bottom along the hardened artificial false roof 14. After the second mining stage is completed, a hydraulic support 15 is installed under the artificial false roof 14 to protect the working space below. According to the characteristics of the roof and floor, metal mesh 21 and anchor bolts 12 are used to support the roof and floor of the coal seam 10.

[0031] After the mining phase is completed, the continuous coal mining machine 20 and other equipment are withdrawn from the continuous mining system of the next mining phase and moved to the working face of the next mining phase. The lowest goaf strip 11 of the goaf 17 of the original mining phase is filled with high water-ash ratio cementing material 13 to construct an artificial false bottom 16, which serves as the artificial false top 14 of the next section. Low water-ash ratio cementing material 18 is filled into the goaf 17 of the mining phase until it covers the hydraulic support 15. After the low water-ash ratio cementing material 18 hardens, the hydraulic support 15 is removed and the remaining space is completely filled.

[0032] During the hardening of the cementing material, adjacent vertical medium-thick and thick coal seams can be mined and backfilled to achieve parallel operations between coal seam groups; the continuous mining machine can be used to repeat the mining and backfilling operations until all mining stages of coal resources are mined.

[0033] As shown in Figure 1, the ventilation system used in near-vertical medium-thick and thick coal seam backfilling mining includes a main shaft 1, an auxiliary shaft 2, and an air shaft 3. The main shaft 1 and auxiliary shaft 2 are for intake air, and the air shaft 3 is for return air. The main shaft 1, auxiliary shaft 2, and air shaft 3 are respectively connected to the horizontally arranged transport roadway 8, track roadway 7, and second-stage transport gate 9. The transport roadway 8 is connected to the second-stage transport gate 9 through the stage connecting roadway 6 and the return air incline 22. The track roadway 7 is connected to the second-stage transport gate 9 through the track incline 19. A coal chute 5 is built in the rock strata to connect the stage connecting roadway 6 with the working face.

[0034] The ventilation routes of the main and auxiliary shafts are as follows: Main shaft 1 - main transport roadway 8 - stage connecting roadway 6 - return air incline 22 - second stage transport gate 9 - ventilation shaft 3; Auxiliary shaft 2 - main track roadway 7 - track incline 19 - working face 4 - coal chute 5 - stage connecting roadway 6 - return air incline 22 - second stage transport gate 9 - ventilation shaft 3.

[0035] The transportation service serves the mining and filling operations. The material transportation route is: auxiliary shaft 2 - main track roadway 7 - track incline 19 - working face 4. The coal crushed by the continuous coal mining machine 20 in the working face is sent to the coal chute 5 via belt conveyor 23. The coal transportation route is: working face 4 - coal chute 5 - stage connecting roadway 6 - main transportation roadway 8 - main shaft 1, as shown in Figure 3.

[0036] Example 1: As shown in Figure 4, (1) shows the state of the coal seam before it is mined, (2) shows the construction of the goaf strip and its reinforcement with anchor bolts 12 and metal mesh 21, (3) shows the state of the artificial false roof 14 during the mining stage, (4) shows the installation space of the hydraulic support 15 under the artificial false roof 14, (5) shows mining under the hydraulic support 15 and the formation of the goaf 17, (6) shows the completion of a mining stage and the construction of the artificial false bottom 16, (7) shows the complete filling of the goaf 17 between the artificial false roof 14 and the artificial false bottom 16 to form a filling body, (8) shows the artificial false bottom 16 of the previous mining stage as the artificial false roof 14 of the current mining stage and the installation of the hydraulic support 15 for mining, and (9) is a schematic diagram of the complete filling of the goaf in the second mining stage.

[0037] Obviously, the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it, and should not be used to limit the scope of protection of the present invention. For those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should be considered as part of the specification.

Claims

1. A method for backfilling and mining near-vertical medium-thick and thick coal seams, characterized in that, The steps are as follows: S1. Arrange a downward working face in the near-vertical coal seam (10) and divide the working face into multiple mining stages according to the depth of the coal seam (10); S2. Construct horizontal goaf strips (11) at the top and bottom of each mining stage, and fill the goaf strips (11) with high water-ash ratio cementing material (13) to form artificial false roof (14) and artificial false floor (16); S3. Mining the working face downward from the artificial false roof (14) until the artificial false floor (16) is reached, forming the goaf area (17) of the mining stage; S4. Completely fill the goaf area (17) with low water-ash ratio cementing material (18); S5. Repeat S2~S4. To achieve backfilling mining of the entire near-vertical medium-thick and thick coal seams; during the process of mining the working face downward from the artificial false roof (14) to the artificial false bottom (16), firstly, a space for horizontally placing hydraulic supports is mined below the artificial false roof (14), and then hydraulic supports (15) that can be suspended on the top and bottom plates of the mining stage are installed under the artificial false roof (14); the hydraulic supports (15) include a top structure that contacts the artificial false roof (14), and devices that can be anchored into the top and bottom plates are provided on both sides of the top structure. The devices that are anchored into the top and bottom plates provide the top structure with the support force applied to the artificial false roof (14); during the mining process of the mining stage, the continuous coal mining machine (20) is first used to move along the mining area. The coal seam (10) is mined in stages to complete the goaf strip (11); after anchor bolts (12) are arranged in the goaf strip (11) at 1000mm×1000mm to connect the roof and floor, high water-cement ratio cementing material (13) is injected into the goaf strip (11) to construct an artificial false roof (14) to support the overlying coal and rock mass; after the artificial false roof (14) hardens, the continuous mining machine (20) is used to mine along the underside of the hardened artificial false roof (14) to form a space to accommodate hydraulic supports (15). Hydraulic supports (15) are installed under the artificial false roof (14) to protect the underside working space. At the same time, according to the characteristics of the roof and floor of the coal seam (10), metal mesh (21) and anchor bolts (12) are used. 2) Support the top and bottom plates; After the mining stage is completed, fill the bottom of the mining stage with high water-cement ratio cementing material (13) to construct an artificial false bottom (16), and fill the goaf (17) with low water-cement ratio cementing material (18) until it covers the hydraulic support (15). After the low water-cement ratio cementing material (18) hardens, remove the hydraulic support (15) and fill the space formed after the hydraulic support (15) is removed. Complete the filling of the goaf (17) between the artificial false top (14) and the artificial false bottom (16); When mining the next mining stage, directly use the artificial false bottom (16) of the previous mining stage as the artificial false top (14) of the next mining stage.

2. The method for backfilling and mining near-vertical medium-thick and thick coal seams according to claim 1, characterized in that, During the hardening of the low water-ash ratio cementing material (18), the near vertical medium-thick and thick coal seams of other strips or coal seam groups are mined and backfilled to achieve parallel operations between coal seam groups; the continuous mining machine (20) is used to mine and backfill until the mining of all medium coal seams (10) in all strips is completed.

3. The method for backfilling and mining near-vertical medium-thick and thick coal seams according to claim 2, characterized in that, The ventilation system used in near-vertical medium-thick and thick coal seam backfilling mining includes a main shaft (1), an auxiliary shaft (2) and a ventilation shaft (3). The main shaft (1) and auxiliary shaft (2) are for intake air, and the ventilation shaft (3) is for return air. The main shaft (1), auxiliary shaft (2) and ventilation shaft (3) are respectively connected to a horizontally set transport roadway (8), a track roadway (7) and a second-stage transport gate (9). The transport roadway (8) is connected to the second-stage transport gate (9) through a stage connecting roadway (6) and a return air uphill (22). The track roadway (7) is connected to the second-stage transport gate (9) through a track uphill (19). A coal chute (5) is constructed in the rock strata to connect the stage connecting roadway (6) and the working face.

4. The method for backfilling and mining near-vertical medium-thick and thick coal seams according to claim 3, characterized in that, The ventilation route of the main shaft is: main shaft (1) - transport roadway (8) - stage connecting roadway (6) - return air uphill (22) - second stage transport gate (9) - ventilation shaft (3); the ventilation route of the auxiliary shaft is: auxiliary shaft (2) - track roadway (7) - track uphill (19) - working face (4) - coal chute (5) - stage connecting roadway (6) - return air uphill (22) - second stage transport gate (9) - ventilation shaft (3).

5. The method for backfilling and mining near-vertical medium-thick and thick coal seams according to claim 4, characterized in that, The material transport route is: auxiliary shaft (2) - main track roadway (7) - track uphill (19) - working face (4); the coal crushed by the continuous coal mining machine (20) in the working face is sent to the coal chute (5) by belt conveyor (23); the coal transport route is: working face (4) - coal chute (5) - stage connecting roadway (6) - transport roadway (8) - main shaft (1).

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