Longwall high-efficiency carbon-free filling mining method

Abstract

The present invention proposes a longwall tunnel-by-tunnel negative carbon high-efficiency filling mining method, comprising: step 1, laboratory testing to obtain the strength of the filling material, the stabilization time t1 of the liquid CO2 and the hardening time t2 of the cementing material; step 2, sequentially solving the width of the branch tunnels of the longwall tunnel-by-tunnel working face K , mining spacing J , and the required filling strength; Step 3, verify whether the filling material in step 1 is qualified; Step 4, fill the branch tunnel. The present invention not only effectively controls the surface subsidence, but also is a new technical path for negative carbon and efficient filling mining.

Description

Technical Field

[0001] The present invention belongs to the technical field of negative carbon high-efficiency filling mining, and in particular relates to a longwall-based tunnel-by-tunnel negative carbon high-efficiency filling mining method. Background Art

[0002] The problem of large amounts of solid waste such as gangue and fly ash generated during the development and utilization of coal also needs to be solved urgently. Most coal mines in my country are underground mining, and the surface subsidence and ecological environment problems caused by underground coal mining are becoming increasingly serious. At present, research on green coal mining and rock deformation control has also become a top priority. Therefore, a negative carbon and efficient filling mining method is urgently needed. Summary of the invention

[0003] The purpose of the present invention is to provide a longwall high-efficiency carbon filling mining method, which not only effectively controls surface subsidence, but also is a new technical path for high-efficiency carbon filling mining, and also a new path for achieving carbon neutrality in the whole process of coal development and utilization. To achieve the above purpose, the technical scheme adopted is as follows:

[0004] A longwall high-efficiency negative carbon filling mining method comprises the following steps:

[0005] Step 1: Laboratory testing to obtain the strength of the filling material The stabilization time t1 of liquid CO2 and the hardening time t2 of the binder; wherein the mixture of the three materials of gangue, binder and liquid CO2 forms the filling material;

[0006] Step 2: sequentially solve the width K of the branch lanes of the longwall working face, the mining spacing J, and the required filling strength φ, which specifically includes the following steps:

[0007] Step 2A: Analyze and solve the width K of the branch lanes of the longwall working face and the mining spacing J by using theoretical analysis and numerical simulation methods;

[0008] Step 2B, the required filling body strength φ when the working face meets the mine ground control requirements;

[0009] Step 3: Verify whether the filling material in step 1 is qualified, specifically including the following steps:

[0010] Step 3A: Based on the mining spacing J and the branch tunnel width K in step 2A, the time t3 for the working face to advance one cycle is solved. If t3> the stabilization time t1 of the liquid CO2, the stabilization time of the filling material in step 1 is qualified; wherein the specific steps for solving t3 include:

[0011] Step 3A1. Calculate the number of branch lanes mined when the working face advances one cycle:

[0012] The advancing length of the working face is L, and the number of branch lanes = L / K;

[0013] The working face advances one cycle, and the number of branch lanes mined = L / (J+K)+1;

[0014] Step 3A2, solve the time t4 for mining a branch lane:

[0015] t4 = branch tunnel length C / daily advance;

[0016] Step 3A3, solve t3:

[0017] t3=t 4* {L / (J+K)+1};

[0018] Step 3B: If the strength of the filling material in step 1 is If it is greater than the required filling body strength φ in step 2C, the filling material strength is qualified;

[0019] Step 4: Filling branch tunnels:

[0020] Grouting pipes and liquid injection pipes are arranged at the highest point of the upper lane of the branch lane to be filled, and a filling retaining wall is set up in the lower lane. Gangue and cementing material are mixed on the ground to form slurry;

[0021] The slurry is injected into the branch tunnel to be filled through the grouting pipe, and the liquid CO2 is simultaneously injected into the branch tunnel to be filled through the liquid injection pipe.

[0022] Preferably, before filling the branch tunnel, a step of designing a filling plan is also included, specifically including:

[0023] According to the length C of the branch tunnel, the branch tunnel is designed to be filled multiple times, and then a waiting time t5 is set after each filling, so that t5> the binder hardening time t2, to prevent the filling slurry from exerting excessive lateral pressure on the filling retaining wall, causing the filling retaining wall to become unstable and cause slurry leakage.

[0024] Preferably, the filling times of a branch lane is 5.

[0025] Preferably, the filling material in step 1 is proportioned according to the strength required by specific engineering conditions.

[0026] Preferably, the gangue in step 1 is loose gangue.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] 1. Through the combination of theoretical analysis and experiments, ensure that the strength of the filling material and the stabilization time of the liquid CO2 in the filling material meet the actual filling requirements.

[0029] 2. The hardening time t2 of the binder is obtained through experiments, which provides a theoretical basis for the waiting time after each filling and improves the filling efficiency.

[0030] 3. It can not only promote the formation of synergistic technical approaches for green mining of coal resources such as CO2 resource utilization and large-scale disposal of solid waste, promote the realization of "carbon-carbon replacement", help accelerate the realization of the "dual carbon" strategic goals in the field of energy resources, and form a new technical path for negative carbon and efficient filling mining, but also is a new path to achieve carbon neutrality in the entire process of coal development and utilization, and can also meet high-requirement surface control standards.

[0031] 4. It provides a reference for negative carbon high-efficiency filling mining, and provides a theoretical reference for negative carbon high-efficiency filling mining method based on longwall tunnel-by-tunnel cemented filling. This design method is simple and easy to implement, with strong technical innovation, easy operation, high economy and practicality, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a cross-sectional diagram of the branch tunnel layout based on the longwall tunnel-by-tunnel negative carbon efficient filling mining method.

[0033] Figure 2 Provide a plan for the branch lane layout.

[0034] Figure 3 This is the workflow diagram of the longwall high-efficiency negative carbon filling mining method.

[0035] Figure 4 This is the numerical simulation diagram of branch lane width.

[0036] Figure 5 This is the numerical simulation diagram of the mining spacing.

[0037] Among them, 1-upper lane; 2-lower lane; 3-filling retaining wall; 4-injection pipe; 5-grouting pipe; 6-branch lane; 7-filling layer. DETAILED DESCRIPTION

[0038] The longwall tunnel-by-tunnel negative carbon efficient filling mining method of the present invention will be described in more detail below in conjunction with a schematic diagram, wherein a preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0039] A longwall high-efficiency negative carbon filling mining method for each lane, forming a longwall working face, using a fully-mechanized excavator or a continuous mining machine to break coal, and mining coal by excavating the branch lanes between the transport lane and the return air lane. After the lane excavation is completed, the filling operation is carried out, that is, when the second branch lane is excavated, the negative carbon filling material is used to fill the first branch lane, and the slurry and liquid CO2 are respectively injected into the filling area through the grouting pipe and the liquid injection pipe to achieve filling and CO2 solidification and sealing. It includes the following steps:

[0040] Step 1: Laboratory testing to obtain the strength of the filling material The stabilization time t1 of liquid CO2 and the hardening time t2 of the binder; wherein the mixture of the three materials of gangue, binder and liquid CO2 forms the filling material;

[0041] The filling materials are proportioned according to the strength required by the specific engineering conditions. The gangue is loose gangue.

[0042] Step 2, sequentially solving the width K, the mining spacing J, and the required filling strength φ of the branch tunnel 6 of the longwall tunnel working face, specifically including the following steps:

[0043] Step 2A: Theoretical analysis and numerical simulation are used to analyze and solve the width K of the branch tunnel 6 of the longwall tunnel working face and the mining spacing J. This step belongs to the prior art.

[0044] Step 2B: The required filling strength φ when the working face meets the mine ground control requirements.

[0045] The ground control requirements of a mine mean, for example, the ground sinks by 5 mm.

[0046] Step 3: Verify whether the filling material in step 1 is qualified, specifically including the following steps:

[0047] Step 3A: Based on the mining spacing J and the width K of the branch tunnel 6 in step 2A, the working face advances a cycle time t3. If t3> the stabilization time t1 of the liquid CO2, the stabilization time of the filling material is qualified. The specific steps for solving t3 include:

[0048] Step 3A1. Calculate the number of branch lanes 6 mined when the working face advances one cycle:

[0049] The advancing length of the working face is L, and the number of branch lanes 6 = L / K;

[0050] The working face advances one cycle, and the number of branch tunnels 6 mined = L / (J+K)+1.

[0051] Step 3A2, solve the time t4 for mining a branch tunnel 6:

[0052] t4 = length of branch tunnel 6 C / day advance;

[0053] Step 3A3, solve t3:

[0054] t3=t 4* {L / (J+K)+1};

[0055] Step 3B: If the strength of the filling material in step 1 is If it is greater than the required filling body strength φ in step 2C, the filling material strength is qualified;

[0056] Step 4: Filling branch tunnel 6:

[0057] The injection pipe 4 and the injection pipe are arranged at the highest point of the upper lane 1 of the branch lane 6 to be filled, and a filling retaining wall is set in the lower lane 2. The gangue and the binder are mixed on the ground to form a slurry;

[0058] The slurry is injected into the branch tunnel 6 to be filled through the grouting pipe 5, and the liquid CO2 is injected into the branch tunnel 6 to be filled through the liquid injection pipe 4 at the same time.

[0059] In this embodiment, before filling the branch tunnel 6, a filling scheme is also designed to prevent the filling slurry from exerting excessive lateral pressure on the filling retaining wall, thereby causing the filling retaining wall to become unstable and cause slurry leakage.

[0060] Specifically include:

[0061] According to the length C of branch tunnel 6, it is designed to fill branch tunnel 6 multiple times, the number of times is 5.

[0062] Then, the waiting time t5 is set after each filling so that t5> the binder hardening time t2.

[0063] Taking a mine as an example, the specific implementation steps are as follows:

[0064] The designed production capacity of a mine in a certain mining area is 6.00Mt / a. At present, the main coal seam is 3# coal. The designed first mining working face is 305 working face. The working face advancement length is 100m, the face length is 80m, the burial depth is 400m, the coal seam thickness is 3-4m, and the average thickness is 3.5m. The longwall cementing filling method is adopted for mining, and the daily advance is 8.0m / d. The surface accumulated waste rock mountain needs to be disposed of, and there is a large reservoir above the working face, which requires water resource protection and has high requirements for surface control.

[0065] (1) The strength of the mixture of loose gangue, binder and liquid CO2 was obtained through laboratory testing And the stabilization time of liquid CO2 in the mixed material is t1 = 24h, and the hardening time of cementitious filling material is t2 = 30h;

[0066] (2) By collecting relevant information such as the actual geological conditions of the working face, the conditions of the coal seam roof and floor, the technical level of tunnel support, and the technical conditions of the tunnel boring machine, the width of branch tunnel 6 and the mining spacing of the longwall tunnel-by-tunnel working face were analyzed through theoretical analysis and numerical simulation. The calculation shows that the width of branch tunnel 6 is 5m and the mining spacing is 10m. Figure 4 , Figure 5 As shown, the mining spacing must be at least twice the width of the branch tunnel 6 to prevent the mining between the branch tunnels 6 from affecting each other.

[0067] According to the simulation results, the required filling strength φ=8MPa when the working face meets the mine ground control requirements. Otherwise, the filling materials in step 1 are re-proportioned.

[0068] (3) The working face advances 100 m, the width of branch tunnel 6 is 5 m, and 20 branch tunnels 6 can be arranged. The mining interval is 10 m, so 7 branches (such as Figure 2 As shown, the first one on the right is the branch tunnel formed after coal seam mining, so it is 100 / (10+5)+1). The length of branch tunnel 6 is 80m, and the daily advance is 8.0m / d. Therefore, the time for advancing a cycle is at least 70d, which needs to be greater than the liquid CO2 stabilization time t1 to ensure that the liquid CO2 is fully stable and will not flow into the adjacent branch tunnel 6. Otherwise, the filling materials in step 1 are re-proportioned.

[0069] like Figure 5 As shown, the first branch tunnel 6 on the left is a schematic diagram of when the coal seam is half mined; the gray area is the coal seam, and the right side is the branch tunnel 6 after filling.

[0070] (4) The filling times are determined to be 5 according to the length of branch tunnel 6. The next filling is carried out after the filling slurry solidifies to ensure that the three materials are fully mixed. The effect of multiple fillings is as follows: Figure 1 As shown, a filling layer is formed after each filling.

[0071] The waiting time after each filling is artificially set, and the waiting time after each filling is greater than the hardening time t2 of the cementing filling material, to prevent the filling slurry from exerting too much lateral pressure on the filling retaining wall, causing the filling retaining wall to become unstable and cause a slurry leakage accident.

[0072] (5) After the tunnel excavation is completed, the backfilling operation is carried out, that is, when the next branch tunnel 6 is excavated, the previously excavated branch tunnel 6 is backfilled. The injection pipe 4 and the injection pipe are arranged at the highest point of the upper tunnel 1 of the branch tunnel 6 to be filled, and the backfilling retaining wall 3 is set in the lower tunnel 2. The loose gangue and the binder are mixed on the ground to form a slurry, such as Figure 1 , Figure 2 shown.

[0073] (6) Before filling, the pipeline needs to be cleaned. Then the slurry is injected into the filling area through the injection pipe 4, and the liquid CO2 is injected into the filling area through the injection pipe at the same time, so as to realize the filling and CO2 solidification and sealing.

[0074] (7) After practical application, the surface subsidence was controlled within 100 mm, and the CO2 utilization rate was 5320~7980m 3 , so this method can effectively control the surface and negative carbon efficient mining.

[0075] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A longwall high-efficiency negative carbon filling mining method, characterized in that: The following steps are involved: Step 1: Laboratory testing to obtain the strength of the filling material The stabilization time t1 of liquid CO2 and the hardening time t2 of the binder; wherein the mixture of the three materials of gangue, binder and liquid CO2 forms the filling material; Step 2: sequentially solve the width K of the branch lanes of the longwall working face, the mining spacing J, and the required filling strength φ, which specifically includes the following steps: Step 2A, theoretical analysis and numerical simulation analysis to solve the width K of the branch lanes of the longwall working face and the mining spacing J; Step 2B, the required filling body strength φ when the working face meets the mine ground control requirements; Step 3: Verify whether the filling material in step 1 is qualified, specifically including the following steps: Step 3A: Based on the mining spacing J and the branch tunnel width K in step 2A, the time t3 for the working face to advance one cycle is solved. If t3> the stabilization time t1 of the liquid CO2, the stabilization time of the filling material in step 1 is qualified; wherein the specific steps for solving t3 include: Step 3A1. Calculate the number of branch lanes mined when the working face advances one cycle: The advancing length of the working face is L, and the number of branch lanes = L / K; The working face advances one cycle, and the number of branch lanes mined = L / (J+K)+1; Step 3A2, solve the time t4 for mining a branch lane: t4 = branch tunnel length C / daily advance; Step 3A3, solve t3: t3=t 4* {L / (J+K)+1}; Step 3B: If the strength of the filling material in step 1 is If it is greater than the required filling body strength φ in step 2B, the filling material strength is qualified; Step 4: Filling branch tunnels: Grouting pipes and liquid injection pipes are arranged at the highest point of the upper lane of the branch lane to be filled, and a filling retaining wall is set up in the lower lane. Gangue and cementing material are mixed on the ground to form slurry; The slurry is injected into the branch tunnel to be filled through the grouting pipe, and the liquid CO2 is simultaneously injected into the branch tunnel to be filled through the liquid injection pipe.

2. The longwall high-efficiency negative carbon filling mining method according to claim 1 is characterized in that: Before filling the branch tunnel, the filling plan is designed, including: According to the length C of the branch tunnel, the branch tunnel is designed to be filled multiple times, and then a waiting time t5 is set after each filling, so that t5> the binder hardening time t2, to prevent the filling slurry from exerting excessive lateral pressure on the filling retaining wall, causing the filling retaining wall to become unstable and cause slurry leakage.

3. The longwall high-efficiency negative carbon filling mining method according to claim 2 is characterized in that: The filling times of a branch lane is 5.

4. The longwall high-efficiency negative carbon filling mining method according to claim 1 is characterized in that: The filling material in step 1 is proportioned according to the strength required by the specific engineering conditions.

5. The longwall high-efficiency negative carbon filling mining method according to claim 1 is characterized in that: The gangue in step 1 is loose gangue.

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