Mining method for filling goaf with coal gangue

Abstract

The invention relates to the technical field of mining methods, in particular to a mining method for a coal gangue filling goaf, which comprises the following steps of: SI, early-stage geological exploration; s2, selecting equipment and constructing a monitoring system; s3, gangue pretreatment and filling material preparation; s4, mining and filling operation; s5, quality detection and evaluation; s6, later maintenance; according to the mining method, the geological structure, the rock mechanics parameters and the hydrogeological conditions of the goaf are analyzed in detail by comprehensively applying the geological radar, the drilling technology, the rock mechanics experiment and the Darcy law. The water guide channel can be found in advance, water inrush accidents are prevented, and a reliable basis is provided for follow-up mining and filling operation; an automatic monitoring system is built, sensors are installed at key positions of a goaf and a filling system, pressure, displacement and flow data are transmitted to a monitoring center in real time through the Internet of Things technology, filling parameters can be adjusted in time according to the monitoring data, and the stability and safety of the filling process are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of mining methods, and in particular to a mining method for filling gob areas with gangue. Background Art

[0002] The mining method for filling gob areas with gangue is a technology that uses gangue as the filling raw material and fills it into the gob area through a specific process, which can control the movement of rock strata, reduce surface subsidence and achieve green mining.

[0003] Some traditional mining methods only rely on simple drilling, and do not understand the geological structure of the gob area, the mechanical parameters of the roof and floor rocks, and the surrounding hydrogeological conditions in detail. It is difficult to discover water-conducting channels in advance and prone to water inrush accidents. At the same time, there is a lack of a perfect monitoring system and it is impossible to collect key data of the gob area and the filling system in real time, such as pressure, displacement and flow rate. This makes it impossible to adjust parameters in time during the mining and filling processes and difficult to ensure the filling quality and the stability of the gob area.

[0004] Therefore, aiming at the problems that some traditional mining methods only rely on simple drilling, do not understand the geological structure of the gob area, the mechanical parameters of the roof and floor rocks, and the surrounding hydrogeological conditions in detail, and at the same time lack a perfect monitoring system, making it difficult to ensure the filling quality and the stability of the gob area, a mining method for filling gob areas with gangue can be designed. Summary of the Invention

[0005] In order to overcome the problems that some traditional mining methods only rely on simple drilling, do not understand the geological structure of the gob area and the mechanical parameters of the roof and floor rocks in detail, and at the same time lack a perfect monitoring system, making it difficult to ensure the filling quality and the stability of the gob area.

[0006] The technical solution of the present invention is: a mining method for filling gob areas with gangue, and its steps are as follows: SI: Preliminary geological exploration SI1: Geological and gob area exploration Use ground penetrating radar and drilling technology to determine the spatial dimensions of the gob area, including length L, width W, and height H; S12: Analysis of gangue characteristics Collect gangue samples, determine the mineral composition by X-ray diffraction, and conduct chemical analysis on the gangue to determine its chemical composition; S13: Determine mining and filling processes According to the characteristics of the gob area and gangue, determine the coal mining process and filling method, and calculate the theoretical filling volume of gangue According to the bulk density of gangue , determine the required mass of gangue ; S2: Selection of Equipment and Setup of Monitoring System S21: Selection of Equipment Select equipment according to the filling plan. During paste filling, the stirring power of the stirring equipment is determined based on the volume of the stirred material stirring time t, and stirring resistance coefficient; S22: Setup of Monitoring System Install sensors at key positions in the goaf and filling system to collect pressure, displacement, and flow data; S3: Pretreatment of Gangue and Preparation of Filling Materials S31: Pretreatment of Gangue Control the particle size of coal gangue below 50 mm through crushing and screening equipment; S32: Preparation of Filling Materials Mix and stir coal gangue, cement, and water according to the designed ratio. For paste filling, control the slurry concentration between 70% - 80% by controlling the water addition to achieve; S4: Mining and Filling Operations S41: Coal Mining Operations Mine according to the established coal mining process, and control the mining height and advancing speed v; S42: Filling Operations After mining is completed, immediately carry out filling operations. Transport the prepared filling materials to the goaf through pipelines, and adjust the filling parameters in real-time according to the monitoring data; S5: Quality Inspection and Evaluation Regularly conduct quality inspections on the filling body by means of core drilling, and evaluate the stability of the goaf through displacement monitoring and stress monitoring; S6: Post-maintenance Conduct long-term monitoring on the goaf and the ground surface.

[0007] Preferably, in SI1, obtain the compressive strength, tensile strength, and elastic modulus parameters of the roof and floor rocks through rock mechanics experiments. Use the groundwater dynamics method to analyze the surrounding hydrogeological conditions through Darcy's law to determine whether there are water-conducting channels, the groundwater level, and flow direction. The height H of the goaf ranges from 1 - 5 m; the compressive strength ranges from 10 - 100 MPa; the permeability coefficient varies according to different geological conditions within the range of - cm / s; Darcy's law is:

[0008] where is the seepage flow rate, is the permeability coefficient, is the hydraulic gradient, is the cross-sectional area of the water flow.

[0009] Preferably, in S12, a laser particle size analyzer is used to measure the particle size distribution. The content of silicon dioxide ( ) in the coal gangue is between 40% - 60%, the content of aluminum oxide ( ) is between 15% - 35%, and the initial average particle size is between 5 - 100 mm.

[0010] Preferably, in S13, for inclined coal seams, the pseudo-inclined flexible shield support coal mining method is used, and the pseudo-inclined angle of the working face is generally controlled between 25° - 30°; the calculation method of the theoretical filling volume of coal gangue is: , where has a density in the range of 1.5 - 2.0 t / m 3 ; meanwhile, plan the gangue transportation route to minimize the transportation distance and reduce the transportation cost.

[0011] Preferably, in S21

[0012] where is the resistance coefficient; Meanwhile, the production capacity of the gangue crushing equipment is determined according to the required amount of coal gangue, and the hourly processing capacity is between 50 - 200 tons.

[0013] Preferably, in S22, through the Internet of Things technology, data is transmitted to the monitoring center in real time. The range of the pressure sensor is determined according to the filling pressure and is between 0 - 20 MPa, and the accuracy of the displacement sensor reaches the millimeter level; the range of the flow sensor is determined according to the conveying flow of the filling material and is between 0 - 100 m 3 / h.

[0014] Preferably, when using a ball mill for grinding in S31, according to the specifications of the ball mill and the grindability index of the coal gangue, determine the grinding time and grinding efficiency. The grindability index is measured through the Hardgrove grindability test and is between 40 - 100; In S32

[0015] where is the target concentration, is the mass of the coal gangue, is the mass of the cement.

[0016] Preferably, the mining height in S41 It is determined according to the coal seam thickness, within the range of 1 - 5 meters. The advancing speed v is determined according to the equipment capacity of the working face and geological conditions, within the range of 0.5 - 5 meters per day. The coal mining face is supported in a timely manner to prevent the roof from caving. A support system composed of single hydraulic props and articulated roof beams is adopted. The support strength is determined according to the roof pressure, within the range of 0.5 - 1.5 MPa.

[0017] Preferably, the 28-day compressive strength of the filling body in S5 reaches 1.5 - 3.0 MPa, and the density is 1.8 - 2.2 t / m 3 ; When evaluating, the Mohr-Coulomb strength criterion is adopted , where is the shear strength, is the cohesion, is the normal stress, is the internal friction angle. By comparing the actual monitoring data, the deformation and stress conditions of the goaf are analyzed.

[0018] Preferably, in S6, a level and a total station are used to monitor the surface settlement and displacement, with the accuracy reaching the millimeter level; according to the characteristics of the local ecological environment, an ecological restoration plan is formulated, the surface is leveled and covered with soil, the thickness of the covered soil is 0.5 - 1.0 meters, and suitable vegetation is planted to restore the ecological environment.

[0019] Advantages of the present invention: 1. The mining method of the present invention comprehensively uses geological radar, drilling technology, as well as rock mechanics experiments and Darcy's law to conduct a detailed analysis of the geological structure of the goaf, rock mechanics parameters, and hydrogeological conditions in the goaf. This helps to discover the water-conducting channels in advance, prevent water inrush accidents, and provide a reliable basis for subsequent mining and filling operations; through X-ray diffraction, chemical analysis, and a laser particle size analyzer, accurately master the mineral composition, chemical composition, and particle size distribution of coal gangue. Based on these characteristics, the coal mining process and filling method can be scientifically selected to improve the filling effect and resource utilization rate; an automated monitoring system is built, sensors are installed at key positions in the goaf and filling system, and pressure, displacement, and flow data are transmitted to the monitoring center in real time through Internet of Things technology. According to the monitoring data, the filling parameters can be adjusted in a timely manner to ensure the stability and safety of the filling process; the filling operation is carried out immediately after coal mining to reduce the risk of roof caving. During the filling process, according to the characteristics of the pipeline, the Bernoulli equation and the continuity equation are used to calculate the flow velocity and pressure loss, and the working parameters of the filling pump are adjusted in a timely manner to ensure the smooth progress of the filling; a level and a total station are used to conduct long-term monitoring of the goaf and the surface, with the accuracy reaching the millimeter level, and problems such as surface settlement and subsidence can be discovered in a timely manner to avoid threatening the surrounding environment and buildings. Description of the Drawings

[0020] Figure 1The following is a flowchart of a mining method for filling goafs with coal gangue according to the present invention. Detailed implementation manners

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Embodiment 1 When using the process of this technical solution, the steps are as follows: S1: Preliminary geological exploration S11: Geological and goaf exploration Using ground penetrating radar and drilling techniques, determine the spatial dimensions of the goaf, including length L, width W, and height H. Obtain the compressive strength, tensile strength, and elastic modulus parameters of the roof and floor rocks through rock mechanics experiments. Use groundwater dynamics methods to analyze the surrounding hydrogeological conditions through Darcy's law to determine whether there are water-conducting channels, as well as the groundwater level and flow direction. The range of the goaf height H is between 1 - 2.5 m; the compressive strength range is between 10 - 50 MPa; the permeability coefficient varies according to different geological conditions within the range of - cm / s; Darcy's law is:

[0023] Among them, is the seepage flow rate, is the permeability coefficient, is the hydraulic gradient, is the cross-sectional area of the flowing water; S12: Analysis of coal gangue characteristics Collect coal gangue samples, determine the mineral composition through X-ray diffraction, and conduct chemical analysis on the coal gangue to determine its chemical composition. Use a laser particle size analyzer to measure the particle size distribution. The content of silicon dioxide ( ) in the coal gangue is between 40% - 50%, the content of aluminum oxide ( ) is between 21% - 35%, and the initial average particle size is between 5 - 100 mm; S13: Determine the mining and filling processes According to the characteristics of the goaf and coal gangue, determine the coal mining process and filling method, and calculate the theoretical filling amount of coal gangue According to the bulk density of coal gangue , determine the required mass of coal gangue , for inclined coal seams, use the pseudo-inclined flexible shield support coal mining method, and the pseudo-inclined angle of the working face is generally controlled between 25° - 30°; the calculation method of the theoretical filling amount of coal gangue is:

[0024]

[0025]

[0026] Among them The density range is between 1.5 - 2.0 t / m 3 At the same time, plan the gangue transportation route, try to shorten the transportation distance, and reduce the transportation cost; S2: Select equipment and build the monitoring system S21: Select equipment Select equipment according to the filling plan. During paste filling, the stirring power of the stirring equipment is determined according to the volume of the stirred material stirring time t and stirring resistance coefficient, where

[0027] is the resistance coefficient; At the same time, the production capacity of the gangue crushing equipment is determined according to the required amount of coal gangue, and the hourly processing capacity is between 50 - 200 tons; S22: Build the monitoring system Install sensors at key positions in the goaf and filling system to collect data on pressure, displacement, and flow. Through Internet of Things technology, transmit the data to the monitoring center in real time. The range of the pressure sensor is determined according to the filling pressure, between 0 - 20 MPa, and the accuracy of the displacement sensor reaches the millimeter level; the range of the flow sensor is determined according to the conveying flow of the filling material, between 0 - 100 m 3 / h; S3: Gangue pretreatment and preparation of filling materials S31: Gangue pretreatment Through crushing and screening equipment, control the particle size of coal gangue below 50 mm. When using a ball mill for fine grinding, determine the grinding time and grinding efficiency according to the specifications of the ball mill and the grindability index of coal gangue. The grindability index is determined through the Hardgrove grindability test, and the range is between 40 - 100; In S32

[0028] Among them is the target concentration, is the mass of coal gangue, is the mass of cement; S32: Preparation of filling materials Mix and stir coal gangue, cement, and water according to the designed ratio. For paste filling, control the slurry concentration between 70% - 80% by controlling the water addition amount to achieve; S4: Mining and filling operations S41: Coal mining operation Mine according to the established coal mining technology and control the mining height and the advancing speed v. The mining height is determined according to the coal seam thickness, ranging from 1 to 5 meters. The advancing speed v is determined according to the working face equipment capacity and geological conditions, ranging from 0.5 to 5 meters per day. Timely support the coal mining face to prevent roof collapse. Adopt a support system composed of single hydraulic props and articulated roof beams. The support strength is determined according to the roof pressure, ranging from 0.5 to 1.5 MPa; S42: Filling operation After mining is completed, immediately carry out the filling operation. Transport the prepared filling materials to the goaf through pipelines and adjust the filling parameters in real time according to the monitoring data; S5: Quality inspection and evaluation Regularly conduct quality inspections on the filling body by means of core drilling, and evaluate the stability of the goaf through displacement monitoring and stress monitoring. The 28-day compressive strength of the filling body reaches 1.5 - 3.0 MPa, and the density is between 1.8 - 2.2 t / m 3 ; When evaluating, adopt the Mohr-Coulomb strength criterion , where is the shear strength, is the cohesion, is the normal stress, is the internal friction angle. Compare the actual monitoring data and analyze the deformation and stress conditions of the goaf; S6: Post-maintenance Conduct long-term monitoring on the goaf and the ground surface. Use a level and total station to monitor the ground settlement and displacement with millimeter-level accuracy; According to the local ecological environment characteristics, formulate an ecological restoration plan, level the ground surface, cover the soil, with the soil covering thickness ranging from 0.5 to 1.0 meters, plant suitable vegetation, and restore the ecological environment.

[0029] Example 2 When using the technology of this technical solution, the steps are as follows: SI: Preliminary geological exploration SI1: Geological and goaf exploration Adopt geological radar and drilling technologies to determine the spatial dimensions of the goaf, including length L, width W, and height H. Obtain the compressive strength, tensile strength, and elastic modulus parameters of the roof and floor rocks through rock mechanics experiments. Use the groundwater dynamics method to analyze the surrounding hydrogeological conditions through Darcy's law to determine whether there are water-conducting channels and the groundwater level and flow direction. The goaf height H ranges from 2.6 to 5 m; The compressive strength ranges from 51 to 100 MPa; The permeability coefficient varies according to different geological conditions, within the range of - cm / s; The Darcy's law is:

[0030] Among them, is the seepage flow rate, is the permeability coefficient, is the hydraulic gradient, is the cross-sectional area of the water flow; S12: Analysis of the characteristics of coal gangue Collect coal gangue samples, determine the mineral composition through X-ray diffraction, conduct chemical analysis on the coal gangue to determine its chemical composition, use a laser particle size analyzer to measure the particle size distribution. The content of silicon dioxide ( ) in the coal gangue is between 51% - 60%, the content of aluminum oxide ( ) is between 15% - 20%, and the initial average particle size is between 5 - 100 mm; S13: Determine the mining and filling processes According to the goaf and the characteristics of coal gangue, determine the coal mining process and filling method, and calculate the theoretical filling volume of coal gangue According to the bulk density of coal gangue , determine the required mass of coal gangue , for inclined coal seams, use the pseudo-inclined flexible shield support coal mining method, and the pseudo-inclined angle of the working face is generally controlled between 25° - 30°; The calculation method of the theoretical filling volume of coal gangue is:

[0031]

[0032]

[0033] Among them The density range is between 1.5 - 2.0 t / m 3 ; At the same time, plan the transportation route of gangue, try to shorten the transportation distance, and reduce the transportation cost; S2: Select equipment and build the monitoring system S21: Select equipment Select equipment according to the filling plan. During paste filling, the stirring power of the stirring equipment is determined according to the volume of the stirred material the stirring time t and the stirring resistance coefficient, where

[0034] is the resistance coefficient; At the same time, the production capacity of the gangue crushing equipment is determined according to the required amount of coal gangue, and the hourly processing capacity is between 50 - 200 tons; S22: Monitoring System Setup Install sensors at key positions in the goaf and filling system to collect data on pressure, displacement, and flow rate. Through Internet of Things technology, transmit the data to the monitoring center in real time. The range of the pressure sensor is determined according to the filling pressure and is between 0 - 20 MPa. The accuracy of the displacement sensor reaches the millimeter level; the range of the flow rate sensor is determined according to the conveying flow rate of the filling material and is between 0 - 100 m 3 / h; S3: Gangue Pretreatment and Filling Material Preparation S31: Gangue Pretreatment Control the particle size of coal gangue below 50 mm through crushing and screening equipment. When using a ball mill for fine grinding, determine the grinding time and grinding efficiency according to the specifications of the ball mill and the grindability index of the coal gangue. The grindability index is determined through the Hardgrove grindability test and ranges between 40 - 100; In S32

[0035] Wherein is the target concentration, is the mass of coal gangue, is the mass of cement; S32: Filling Material Preparation Mix and stir coal gangue, cement, and water according to the designed ratio. For paste filling, control the slurry concentration between 70% - 80% by controlling the amount of water added to achieve; S4: Mining and Filling Operations S41: Coal Mining Operations Mine according to the established coal mining process, control the mining height and the advancing speed v. The mining height is determined according to the coal seam thickness and ranges between 1 - 5 meters. The advancing speed v is determined according to the equipment capacity of the working face and geological conditions and ranges between 0.5 - 5 meters per day. Timely support the coal mining face to prevent roof collapse. Use a support system composed of single hydraulic props and articulated roof beams. The support strength is determined according to the roof pressure and ranges between 0.5 - 1.5 MPa; S42: Filling Operations After mining is completed, immediately carry out filling operations. Transport the prepared filling material to the goaf through pipelines and adjust the filling parameters in real time according to the monitoring data; S5: Quality Inspection and Evaluation Regularly conduct quality inspections on the filling body by means of core drilling, and evaluate the stability of the goaf through displacement monitoring and stress monitoring. The 28 - day compressive strength of the filling body reaches 1.5 - 3.0 MPa, and the density is between 1.8 - 2.2 t / m3 ; During the evaluation, the Mohr-Coulomb strength criterion is adopted , where is the shear strength, is the cohesion, is the normal stress, is the internal friction angle. By comparing the actual monitoring data, analyze the deformation and stress conditions of the goaf; S6: Post-maintenance Conduct long-term monitoring on the goaf and the ground surface. Use a level and a total station to monitor the ground settlement and displacement, with the accuracy reaching the millimeter level; According to the characteristics of the local ecological environment, formulate an ecological restoration plan, level the ground surface and cover it with soil. The thickness of the covered soil is 0.5 - 1.0 meters, plant suitable vegetation, and restore the ecological environment.

[0036] Experimental example Take Examples 1 and 2 as examples, and conduct experiments in three groups using the traditional caving method in Example 3. The experimental period is two years. Detect the values of ground subsidence, coal recovery rate, filling cost, ecological restoration cost, and goaf stability. The data results are as follows;

Claims

1. A mining method for filling goafs with coal gangue, characterized in that, The steps are as follows: SI: Preliminary geological exploration SI1: Geological and goaf exploration Using ground-penetrating radar and drilling techniques, determine the spatial dimensions of the goaf, including length L, width W, and height H; S12: Analysis of coal gangue characteristics Collect coal gangue samples, determine the mineral composition through X-ray diffraction, and conduct chemical analysis on the coal gangue to determine its chemical composition; S13: Determine the mining and filling processes Determine the coal mining technology and filling method according to the characteristics of the goaf and gangue, and calculate the theoretical filling volume of gangue According to the bulk density of gangue , determine the required mass of gangue ; S2: Select equipment and build a monitoring system S21: Select equipment Select equipment according to the filling plan. During paste filling, the stirring power of the stirring equipment is determined according to the volume of the stirred material , stirring time t and stirring resistance coefficient. S22: Build a monitoring system Install sensors at key positions in the goaf and filling system to collect pressure, displacement, and flow data; S3: Pretreatment of gangue and preparation of filling materials S31: Pretreatment of gangue Control the particle size of coal gangue below 50 mm through crushing and screening equipment; S32: Preparation of filling materials Mix the gangue, cement and water according to the designed ratio. For paste filling, control the slurry concentration between 70% and 80% by controlling the water addition amount to achieve; S4: Mining and filling operations S41: Coal mining operations Mining is carried out according to the established coal mining technology, and the mining height and the advancing speed v are controlled. S42: Filling operations After mining is completed, immediately carry out filling operations. Transport the prepared filling materials to the goaf through pipelines, and adjust the filling parameters in real time according to the monitoring data; S5: Quality inspection and evaluation Regularly conduct quality inspection on the filling body by means of core drilling, and evaluate the stability of the goaf through displacement monitoring and stress monitoring; S6: Post-maintenance Conduct long-term monitoring on the goaf and the ground surface.

2. The mining method for filling goaf with gangue according to claim 1, characterized in that: In SI1, the compressive strength, tensile strength and elastic modulus parameters of the roof and floor rocks are obtained through rock mechanics experiments. Using the groundwater dynamics method, the surrounding hydrogeological conditions are analyzed through Darcy's law to determine whether there is a water-conducting channel, as well as the groundwater level and flow direction. The height H of the goaf ranges from 1 to 5 m; the compressive strength ranges from 10 to 100 MPa; the permeability coefficient varies in the range of - cm / s according to different geological conditions; Darcy's law is: Among them, is the seepage flow rate, is the permeability coefficient, is the hydraulic gradient, is the cross-sectional area of the flow-through section.

3. The mining method for filling goaf with coal gangue according to claim 1 is characterized in that: The particle size distribution was measured using a laser particle size analyzer in S12. The content of silicon dioxide ( in the coal gangue is between 40% and 60%, the content of aluminum oxide ( is between 15% and 35%, and the initial average particle size is between 5 and 100 mm.

4. The mining method for filling gob areas with coal gangue according to claim 1, characterized in that: In S13, for inclined coal seams, the pseudo-inclined flexible shield support coal mining method is used, and the pseudo-inclined angle of the working face is generally controlled at 25°-30°; the calculation method of the theoretical filling volume of coal gangue is as follows: , where has a density range of 1.5-2.0 t / m 3 ; at the same time, plan the gangue transportation route, try to shorten the transportation distance, and reduce the transportation cost.

5. The mining method for filling goaf with gangue according to claim 1, characterized in that: In S21: wherein is the drag coefficient; Meanwhile, the production capacity of the gangue crushing equipment is determined according to the required amount of coal gangue, and the hourly processing capacity is between 50 and 200 tons.

6. The mining method for filling goaf with coal gangue according to claim 1, characterized in that: In S22, through the Internet of Things technology, data is transmitted to the monitoring center in real time. The range of the pressure sensor is determined according to the filling pressure, and the range is between 0 - 20 MPa. The accuracy of the displacement sensor reaches the millimeter level. The range of the flow sensor is determined according to the conveying flow of the filling material, and the range is between 0 - 100 m 3 / h.

7. The mining method for filling goaf with gangue according to claim 1, characterized in that: When using a ball mill for fine grinding in S31, determine the grinding time and grinding efficiency according to the specifications of the ball mill and the grindability index of the coal gangue. The grindability index is determined through the Hardgrove grindability test and ranges from 40 to 100; In S32: wherein is the target concentration, is the mass of coal gangue, is the mass of cement.

8. The mining method for filling goaf with gangue according to claim 1, characterized in that: Mining height in S41 It is determined according to the coal seam thickness, with a range of 1 - 5 meters. The advancing speed v is determined according to the working face equipment capacity and geological conditions, with a range of 0.5 - 5 meters per day. The coal mining face is timely supported to prevent roof caving. A support system composed of single hydraulic props and articulated roof beams is adopted, and the support strength is determined according to the roof pressure, with a range between 0.5 - 1.5 MPa.

9. A mining method for filling goafs with coal gangue according to claim 1, characterized in that: The 28-day compressive strength of the filling body in S5 reaches 1.5 - 3.0 MPa, and the density is 1.8 - 2.2 t / m 3 ; During the evaluation, the Mohr-Coulomb strength criterion is adopted where is the shear strength, is the cohesion, is the normal stress, is the angle of internal friction; Compare the actual monitoring data and analyze the deformation and stress conditions of the goaf.

10. The mining method for filling goaf with gangue according to claim 1, characterized in that: In S6, use a level and total station to monitor the ground settlement and displacement, with an accuracy reaching the millimeter level; According to the local ecological environment characteristics, formulate an ecological restoration plan, level the ground surface, cover the soil, with the soil covering thickness being 0.5 - 1.0 meters, plant suitable vegetation, and restore the ecological environment.

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