Top coal caving mining method for single steeply inclined extra-thick coal seams

Abstract

This invention discloses a method for top-coal caving mining of a single steeply inclined extra-thick coal seam, relating to the field of coal mine mining technology. The method includes: excavating along the strike direction of the coal seam roof on the haulage uphill side; excavating a corresponding roadway on the return air uphill side; excavating two cut-outs along the true thickness of the coal seam towards the coal seam floor from the two excavated roadways; and excavating a roadway to connect the ends of the two cut-outs. During operation, a fully mechanized top-coal caving mining method is used. After the working face advances, support is provided at the coal seam floor, and a floor roadway is pre-reserved. Side-support is provided for the pre-reserved roadway behind the hydraulic supports at the floor. A concrete wall is poured outside the individual hydraulic supports, and a windbreak curtain is formed by injecting cement grout into the goaf behind the working face, maintaining a "W"-shaped ventilation system at the working face. This invention achieves roadway retention simultaneously with coal mining, reducing the time and cost required for separate roadway retention.

Description

Technical Field

[0001] This invention relates to the field of coal mine steeply inclined extra-thick coal seam mining technology, specifically to a method for top coal caving mining of a single steeply inclined extra-thick coal seam. Background Technology

[0002] Steeply inclined coal seams account for approximately 4% of my country's total coal reserves, and these resources are largely high-quality. When mining steeply inclined coal seams, because the seam angle is greater than 45°, the layout of the access roadways and the mining methods differ significantly from those for gently inclined seams. Currently, commonly used mining methods for steeply inclined coal seams include reverse bench mining, inclined bench mining, and pseudo-inclined flexible shield support mining.

[0003] The above-mentioned coal mining methods also have the following technical problems:

[0004] Firstly, the goaf of steeply inclined coal seams is not easy to completely seal off, and there are many air leakage channels, which can easily lead to spontaneous combustion of residual coal in the goaf.

[0005] Secondly, the ventilation system needs improvement. Currently, there are common problems such as unreasonable ventilation systems and insufficient effective air volume, which seriously affect the safe production of the mine.

[0006] Third, the tunneling work is extensive, requiring the excavation of two tunnels within the coal seam to address ventilation issues, which is costly.

[0007] Therefore, the aforementioned existing technologies need further improvement. Summary of the Invention

[0008] The purpose of this invention is to provide a method for top coal caving mining of a single steeply inclined extra-thick coal seam, which only requires mining one coal seam roadway and can achieve roadway retention at the same time as mining, that is, mining and roadway retention are carried out simultaneously, which improves mining efficiency and reduces the time and cost required for separate roadway retention.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for top-coal caving mining of a single steeply inclined extra-thick coal seam includes the following steps:

[0011] S1. A tunnel is formed by excavating a certain distance along the direction of the coal seam at the top of the coal seam on the side of the transport uphill section.

[0012] At the top of the coal seam on the return air uphill side, a distance is excavated along the direction of the coal seam to form another roadway;

[0013] The two tunnels were excavated in opposite directions, resulting in their relative positions.

[0014] A coal pillar of a certain length is left between the two roadways;

[0015] S2. At the end of the two roadways formed in step S1, excavate along the horizontal direction of the true thickness of the coal seam until the bottom of the coal seam is reached. After the excavation is completed, an upper cut-out and a lower cut-out are formed.

[0016] S3. Excavate a roadway of a certain width along one side of the coal seam floor, so that the ends of the upper and lower cut-outs near the coal seam floor remain connected.

[0017] S4. Support the roof and sides of the roadway near the coal seam floor, and install hydraulic supports in the upper cut for support.

[0018] S5. A coal mining machine is arranged in front of the hydraulic support. The coal mining machine mines coal along the working face advance direction. At the same time as mining coal, a reserved roadway space is formed at the bottom of the coal seam. The roof and sides of the reserved roadway are supported.

[0019] After the support is completed, the sliding frame is pushed forward; at the same time, a single hydraulic prop is arranged on the side of the reserved goaf area of ​​the roadway behind the hydraulic support.

[0020] The steps are: sequential cyclic coal mining - reserved roadway roof and side support - push conveyor and move frame - hydraulic support rear support;

[0021] S6. A concrete wall of a certain width is poured on the outside of the single hydraulic prop. After the concrete has fully set, the single hydraulic prop is removed. As the working face advances, the concrete wall is gradually poured. At the same time, the goaf area is grouted in sections behind the working face to form a windbreak curtain.

[0022] S7. The fresh air flow direction is: transport uphill - roof roadway - coal mining face - reserved roadway at the bottom of the coal seam - downcut - return air uphill, forming a "W" shaped ventilation system.

[0023] The beneficial technical effects directly brought about by the above technical solution are as follows:

[0024] By redesigning the coal mining method, roadways are formed while mining, eliminating the need for separate roadway excavation. In addition, by leaving coal pillars between the two roadways, not only do they provide support, but more importantly, they coordinate with the cut-off, transport uphill, return air uphill, roof roadways, and coal mining face to form a W-shaped ventilation system for the working face, ensuring good ventilation.

[0025] As a preferred embodiment of the present invention, in step S1, the total length of the roadway formed by excavating a certain distance along the coal seam direction at the coal seam roof on the transport uphill side, and the other roadway formed by excavating a certain distance along the coal seam direction at the coal seam roof on the return air uphill side, together with the coal pillar, is equal to the length of the coal seam roof.

[0026] As another preferred embodiment of the present invention, in step S4, anchor mesh support is provided at the top and sides of the roadway near the coal seam floor.

[0027] Furthermore, in step S6, the interval between adjacent zones within the goaf is 5-10 meters, and the windbreak curtain prevents fresh airflow from entering the goaf and causing spontaneous combustion of residual coal.

[0028] Furthermore, the thickness of the coal seam is ≥8 meters.

[0029] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0030] This invention proposes a single steeply inclined extra-thick coal seam top coal caving mining method. During the mining process, only one roadway needs to be excavated at the working face, while another roadway is generated during the mining process, eliminating the need to excavate another roadway separately, thus reducing the amount of roadway excavation.

[0031] By creating reserved roadways during coal mining, that is, by carrying out coal mining and roadway reservation simultaneously, coal mining efficiency is improved.

[0032] By installing windbreak curtains, it is possible to prevent fresh air from entering the goaf and causing spontaneous combustion of residual coal.

[0033] This invention forms a "W"-shaped ventilation system through the coordinated operation of the cutting face, transport uphill, return air uphill, roof roadway, and coal mining face. This system ensures that the working face is always under full air pressure, resulting in excellent ventilation. Furthermore, the "W"-shaped ventilation method shortens the airflow distance within the working face, which is beneficial for cooling, dust removal, reducing air leakage, and facilitating fire prevention. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings:

[0035] Figure 1 This is a cross-sectional view of the steeply inclined, extra-thick coal seam roadway layout of the present invention;

[0036] Figure 2 This is a plan view of the layout of steeply inclined, extra-thick coal seam roadways according to the present invention;

[0037] Figure 3 This is a schematic diagram of the mining operation of a steeply inclined, extra-thick coal seam in this invention.

[0038] In the picture:

[0039] 1. Coal seam roof, 2. Coal seam floor, 3. Coal seam, 4. Roadway, 5. Air door, 6. Fresh air flow, 7. Transport uphill, 8. Coal pillar, 9. Upper cut-off, 10. Lower cut-off, 11. Return air uphill, 12. Working face advance direction, 13. Hydraulic support, 14. Concrete wall, 15. Goaf, 16. Grouting pipe, 17. Sewage air direction. Detailed Implementation

[0040] This invention proposes a method for top coal caving mining of a single steeply inclined extra-thick coal seam. To make the advantages and technical solutions of this invention clearer and more explicit, the invention will be further described below with reference to specific embodiments.

[0041] The "extra-thick coal seam" mentioned in this invention refers to a coal seam with a thickness of ≥8 meters.

[0042] In this invention, the "coal seam roof" refers to the "steeply inclined extra-thick coal seam roof", and the "coal seam floor" refers to the "steeply inclined extra-thick coal seam floor".

[0043] The main technical concept of this invention is that by redesigning the coal mining method, the following advantages can be achieved simultaneously: firstly, only one roadway needs to be excavated; secondly, coal mining and roadway retention can be carried out simultaneously; and thirdly, a "W"-shaped ventilation system can be formed. The combination of the above three features solves the technical problem that has been sought to be solved in this field—improving coal mining efficiency while reducing the amount of tunneling and ensuring good ventilation at the working face.

[0044] like Figure 1 As shown, the coal seam roof 1, coal seam floor 2, coal seam 3, and roadway 4 are illustrated.

[0045] like Figure 2 As shown, the diagram illustrates the following: air damper 5, fresh air flow 6, transport uphill 7, coal pillar 8, upper cut-out 9, lower cut-out 10, and return air uphill 11. The air damper 5 uses a structure already available in the prior art, while the coal pillar 8, upper cut-out 9, and lower cut-out 10 are all designed based on the technical problems solved by this invention.

[0046] This invention mainly employs a top-coal caving mining method, which includes:

[0047] First, tunneling is carried out along the direction of the coal seam at the top of the coal seam on the transport uphill side, and a corresponding roadway is carried out on the return air uphill side, with a coal pillar of length c meters left in the middle.

[0048] Secondly, two cuts are excavated in the two roadways obtained after the above-mentioned excavation, along the horizontal direction of the true thickness of the coal seam, towards the bottom plate of the steeply inclined thick coal seam. A roadway is then excavated to connect the ends of the two cuts, forming a "W"-shaped ventilation system of transport uphill - roof roadway - upper cut - lower cut - return air uphill.

[0049] When the coal mining machine is working, a fully mechanized top-coal caving mining method is adopted, and the working face advances along the strike. After the working face advances, anchor wire mesh and individual hydraulic props are used for support at the coal seam floor, and floor roadways are reserved in advance. At the same time, roadway-side support is provided for the reserved roadway behind the hydraulic support 13 at the floor. A concrete wall of a certain width is poured on the outside of the deployed individual hydraulic props. After the concrete has set, the individual hydraulic props are removed. Meanwhile, a windbreak curtain is formed by injecting cement slurry into the goaf behind the working face, so that fresh air flows along the transport uphill - roof roadway - coal mining face - reserved floor roadway - cut-off - return air uphill, maintaining a "W" shaped ventilation system at all times.

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] Combination Figures 1 to 3 As shown, the specific steps include:

[0052] Step 1: On the side of the transport uphill 7, excavate b meters along the coal seam direction at the coal seam roof 1. On the side of the return air uphill 11, excavate d meters along the coal seam direction at the coal seam roof 1. Excavate in opposite directions. After both are completed, leave a c-meter coal pillar and ensure that:

[0053] Coal seam roof length = b + c + d;

[0054] Step 2: At the end of the two roadways, excavate two cut holes along the horizontal direction of the true thickness of the coal seam, namely upper cut hole 9 and lower cut hole 10, until the coal seam floor 2 is reached;

[0055] Step 3: Excavate a roadway with a width of a meters along the 2nd side of the coal seam floor until the ends of the two cuts are connected to form a "W" shaped ventilation system. Anchor mesh support is installed at the top and sides of the roadway near the coal seam floor. Coal pillars 8 are left and hydraulic supports 13 are installed in the cuts arranged along the working face advance direction 12 for support.

[0056] Step 4: Deploy the coal mining machine in front of the hydraulic support. The coal mining machine mines coal along the working face advance direction, providing support for the reserved roadway space at the coal seam floor, specifically anchor mesh support for the top and sides of the reserved roadway. After support is completed, push the conveyor belt forward. Simultaneously, deploy individual hydraulic props on the goaf side of the reserved roadway behind the hydraulic support. The process is repeated in a cycle: coal cutting – roof and side support of the reserved roadway – pushing the conveyor belt – individual prop support behind the support.

[0057] Step 5: Pour a concrete wall 14 of a certain width outside the deployed individual hydraulic props. After the concrete has fully set, remove the individual hydraulic props. As the working face advances, the concrete wall 14 is gradually completed. Simultaneously, inject cement grout at 5-10 meter intervals into the goaf 15 behind the working face to form a windbreak curtain, preventing fresh air from entering the goaf and causing spontaneous combustion of residual coal. Fresh air is transported uphill into the roof roadway, into the coal face, into the reserved floor roadway, into the cut-off, and into the return air uphill, as... Figure 3 The direction of the polluted air, indicated by 17, maintains a "W" shaped ventilation system.

[0058] Furthermore, grouting pipes 16 are installed in the goaf area, that is, one grouting pipe is installed at intervals, and multiple pipes are installed to grout the goaf area.

[0059] The structure and usage of the "coal mining machine", "hydraulic support", and "single hydraulic prop" mentioned in this invention can be implemented by those skilled in the art by referring to existing technologies.

[0060] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0061] It should be noted that any equivalent or obvious modifications made by those skilled in the art under the guidance of this specification should be within the scope of protection of this invention.

Claims

1. A single steeply inclined extremely thick coal seam top coal caving mining method characterized in that, Comprise the following steps in turn: S1, excavate a distance along the coal seam strike direction at the coal seam roof on the side of the transport up mountain, to form a roadway; Excavate a distance along the coal seam strike direction at the coal seam roof on the side of the return air up mountain, to form another roadway; Both excavate in opposite directions; After both are excavated, leave a certain length of coal pillar between the two roadways; S2, excavate along the true thickness horizontal direction of the coal seam at the terminal position of the two roadways formed by step S1, until the coal seam floor, to form an upper cut and a lower cut after the excavation is completed; S3, excavate a roadway of a certain width along the coal seam floor side, so that the end of the upper cut and the lower cut near the coal seam floor side remains connected; S4, support at the roof and sides of the roadway near the coal seam floor, and arrange hydraulic supports in the upper cut for support; S5, arrange a coal mining machine in front of the hydraulic supports, and advance the coal mining machine along the working face advancing direction to mine coal, while forming a reserved roadway space at the coal seam floor, and support the roof and sides of the reserved roadway; After the support is completed, push the supports forward; at the same time, arrange a single hydraulic prop on the side of the reserved roadway goaf behind the hydraulic supports; In turn, cycle the steps of "mining - reserved roadway roof and side support - push the supports forward - support behind the hydraulic supports"; S6, pour a concrete wall of a certain width outside the single hydraulic prop, after the concrete is fully cured, remove the single hydraulic prop, and as the working face advances, the concrete wall is gradually poured; at the same time, carry out zonal grouting behind the working face to form a wind blocking curtain; S7, the fresh air flow direction is transport up mountain - roof roadway - coal mining working face - reserved roadway at the coal seam floor - lower cut - return air up mountain, to form a "W" type ventilation system; In step S1, the total length of the roadway excavated a distance along the coal seam strike direction at the coal seam roof on the side of the transport up mountain, the other roadway excavated a distance along the coal seam strike direction at the coal seam roof on the side of the return air up mountain, and the coal pillar is equal to the length of the coal seam roof.

2. The top coal caving method for a single steeply inclined extremely thick coal seam according to claim 1, characterized in that: In step S4, anchor net support is carried out at the roof and sides of the roadway near the coal seam floor.

3. The top coal caving method for a single steeply inclined extremely thick coal seam according to claim 1, characterized in that: In step S6, the interval between adjacent zones in the goaf is 5-10 meters, and the wind blocking curtain prevents fresh air from entering the goaf to cause spontaneous combustion of residual coal.

4. The top coal caving method for a single steeply inclined extremely thick coal seam according to claim 1, characterized in that: The thickness of the coal seam is ≧8 meters.

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