Method for collaborative optimization of open-pit mine slope shape and mining procedure of composite coal seam soft rock

Abstract

This application proposes a method for the coordinated optimization of slope morphology and mining procedures in open-pit coal mines with soft rock and composite coal seams. Belonging to the field of open-pit coal mining technology, this method, under the premise of meeting the slope safety reserve coefficient, uses two-dimensional numerical simulation software to design various slope morphologies for each slope region, obtaining slope mining parameters and slope cross-sectional morphology for each scheme during top-down longitudinal mining. Combining the slope mining parameters and slope cross-sectional morphology of each scheme during top-down longitudinal mining, and considering the three-dimensional retaining effect of the internal spoil heap during the tracking and lining process, each slope region is optimized in stages. Three-dimensional numerical simulation software is used to determine the internal spoil heap tracking distance during transverse coal seam mining, ultimately determining the mining parameters, optimized slope spatial morphology, and lining height when transverse and longitudinal mining are carried out simultaneously from bottom to top. This application maximizes the recovery of coal resources covered by end slopes, guides open-pit coal mine operations, and improves the coal resource recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of open-pit coal mining technology, specifically involving a method for the coordinated optimization of slope morphology and mining procedures in soft rock open-pit mines with composite coal seams. Background Technology

[0002] In existing technologies, optimizing slope morphology and mining procedures for open-pit mines with soft rock in composite coal seams typically offers the following advantages: First, it allows for rapid release and full utilization of internal drainage space, shortens transportation distances, reduces external drainage costs, effectively lowers production costs, and improves the economic benefits of open-pit mines. Second, it shortens the exposure space and time of weak layers on the slopes of open-pit mines in composite coal seams, thereby improving slope stability. Third, it increases the amount of coal resources recovered from open-pit mines and extends the service life of the mining area.

[0003] For example, patent CN118895974A discloses a method for strong drainage and steep slope mining in open-pit mines. This method involves zoned mining of composite coal seams, providing parameters for the working side, end side, and inner spoil heap benches, as well as methods for determining the safe distance between the working side and the inner spoil heap in multi-coal seams, and methods for determining the mining process. This guides open-pit strong drainage and steep slope mining operations and improves mining efficiency and quality. Patent CN112855162A discloses a method for mining the upper coal seam of the end side in open-pit mines with composite coal seams, which utilizes the benches of the inner spoil heap to create working space and arrange mining equipment. The method involves using the working platform of the inner spoil heap to carry out segmented recovery of the coal seam overlying the upper coal seam, extracting the upper coal seam and the interbedded rock between the coal seam and the mining level, and indicating that the length of the end-side coal recovered in the advancing direction is equal to the width of the spoil heap platform; Patent CN113742949B discloses a method for determining the mining width of high-level coal seams in open-pit mines with composite coal seams. This method adjusts the width of each platform between coal seams, calculates the difference between the width of the platform before and after the adjustment, finds the relationship between the width of the platform and the mining width, and uses the horizontal mining inner spoil support effect to extract the high-level coal seam.

[0004] These patents all focus on open-pit mining methods and the width of upper coal seam mining, without considering the relationship between slope morphology and mining procedures in soft rock open-pit coal mines. This leads to an imbalance between waste disposal space release and slope stability control. Therefore, there is an urgent need to find a method for the coordinated optimization of slope morphology and mining procedures in composite coal seam soft rock open-pit mines to provide technical support for subsequent open-pit coal mining. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application proposes a method for the coordinated optimization of slope morphology and mining procedures in open-pit mines with composite coal seams and soft rock, including:

[0006] Obtain a representative two-dimensional calculation profile of the slope;

[0007] Based on the two-dimensional calculation profile of the slope, the coal seams in the slope body are numbered sequentially from top to bottom, and the weak layers in the slope body are numbered sequentially from top to bottom. The location of the weak layers in the slope body is used as the dividing line, and each layer of the slope is numbered from top to bottom to obtain each slope region.

[0008] Based on the open-pit coal mine design, determine the bench form and mining parameters of the transverse mining working side, longitudinal mining working side, end side, and internal spoil heap slope of each coal seam in the composite coal seam;

[0009] According to the "Design Code for Open-pit Coal Mines", the slope safety reserve coefficient is determined based on the slope service life when mining each area with the weak layer as the dividing line.

[0010] Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slope of the longitudinal mining working side, end side, and inner spoil disposal site, as well as the mining parameters, various slope morphology designs are carried out for each slope area to obtain the mining parameters and slope cross-sectional morphology of each scheme when mining longitudinally from top to bottom.

[0011] Based on the mining parameters and slope cross-sectional shape of each scheme during top-down vertical mining, and considering the three-dimensional retaining effect of the internal spoil heap on the slope during the lining process, the slope areas are optimized in stages to determine the mining parameters, slope spatial optimization shape, and lining height when bottom-up horizontal and vertical mining are carried out simultaneously.

[0012] A finite element calculation model was established based on the optimized shape of the slope space and the height of the rib, and the three-dimensional numerical simulation software was used to determine the internal discharge tracking distance of the coal seam in the transverse mining.

[0013] Based on the current status of the mining area and the optimized shape of the slope space, the morphological parameters of the end slope at each stage are determined.

[0014] Based on the current status of the mining area and the morphological parameters of the end slopes at each stage, the mining stages are refined. Based on the tracing distance of the coal seam in the transverse mining, a plan view of the engineering location at each stage is drawn. A Gantt chart of the slope mining progress is drawn according to the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining.

[0015] The process of obtaining a representative two-dimensional calculation profile of the slope includes:

[0016] Obtain three-dimensional geological models, slope morphology, and historical geological drilling information;

[0017] Based on the three-dimensional geological model, slope morphology, and historical geological drilling information, representative two-dimensional calculation profiles of the slope are selected.

[0018] The location of weak layers within the slope body is used as the dividing line. Each layer of the slope is numbered from top to bottom to obtain each slope region, including:

[0019] The slope region from the R1 weak layer to the ground surface is designated as slope region P1, the slope region between the R2 weak layer and the R1 weak layer is designated as slope region P2, and so on. n weak layer to R n-1 The slope region between weak layers is numbered as slope region P. n .

[0020] The mining parameters include: bench height, flatbed width, and bench slope angle.

[0021] Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slopes of the longitudinal mining working face, end face, and internal spoil heap, as well as the mining parameters, various slope morphology designs are carried out for each slope area to obtain the mining parameters and slope cross-sectional morphology of each scheme when mining longitudinally from top to bottom, including:

[0022] Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slope of the longitudinal mining working side, end side, and inner spoil disposal site, as well as the mining parameters, various slope morphology designs are carried out for each slope area using the longitudinal mining procedure, resulting in various slope cross-section morphology schemes.

[0023] The number of stages is determined based on the number of weak layers within the slope.

[0024] Based on the number of stages, the Morgenstern method is used to obtain the slope stability coefficient of each region for each slope cross-section scheme. The width of each flat plate is adjusted until the slope stability coefficient of each region meets the constraint conditions. The adjustment of the width of each flat plate is then stopped, thus obtaining the mining parameters and slope cross-section morphology of each scheme when mining vertically from top to bottom.

[0025] The constraint condition is calculated as follows:

[0026] |Fs n -K n | <M

[0027] Among them, Fs n Let M be the slope stability coefficient for the nth stage, and K be a preset threshold value. n This represents the safety reserve coefficient for the nth stage.

[0028] The morphological parameters of the end slope at each stage include: the optimized height of each horizontal step, the optimized width of the flat plate, and the optimized slope angle of the step.

[0029] The mining stages are refined based on the current status of the mining area and the morphological parameters of the end slopes at each stage. Based on the tracing distance of the coal seam's transverse mining, a plan view of the engineering location for each stage is drawn. Furthermore, a Gantt chart of the slope mining progress is drawn according to the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining, including:

[0030] The mining stages are refined based on the current status of the mining site and the morphological parameters of the end slopes at each stage.

[0031] Based on the tracking distance of the coal seam's transverse mining internal dump, the location of the mining project, the bench form of the transverse mining working side, the longitudinal mining working side, the end side, the internal dump site, and the mining parameters, draw a plan view of the project location at each stage.

[0032] A Gantt chart of the slope mining progress is drawn based on the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining.

[0033] Beneficial effects:

[0034] This application proposes a method for the coordinated optimization of slope morphology and mining procedures in open-pit mines with composite coal seams and soft rock. Based on the stability of the end slopes, it comprehensively considers the mining parameters, tracking distances, and development sequences of the internal spoil heap and the transverse and longitudinal mining working faces of each coal seam. Two-dimensional and three-dimensional numerical simulation software are used to design the slope morphology, maximizing the recovery of coal resources overlaid by the end slopes. The core of this method lies in constructing a coordinated optimization approach for slope morphology and mining procedures to guide open-pit coal mine operations and improve coal resource recovery rates. Attached Figure Description

[0035] Figure 1 Flowchart of the method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mine according to an embodiment of this application;

[0036] Figure 2 This application provides a schematic diagram of the numbering of coal seams, weak layers, and slope areas in an embodiment.

[0037] Figure 3 A schematic diagram of the slope cross-sectional shape of region P2 in Scheme 1 of this application embodiment;

[0038] Figure 4 This application provides a schematic diagram of the slope cross-sectional shape of region P3 in Scheme 1 of the present application.

[0039] Figure 5 This application provides a schematic diagram of the slope cross-sectional shape of region P4 in Scheme 1 of the present application.

[0040] Figure 6 This application's embodiment of the first scheme shows a schematic diagram of the slope cross-sectional shape during longitudinal mining from top to bottom.

[0041] Figure 7 A schematic diagram of the slope cross-sectional shape of region P2 in embodiment 2 of this application;

[0042] Figure 8 A schematic diagram of the slope cross-sectional shape of region P3 in Scheme 2 of this application embodiment;

[0043] Figure 9 A schematic diagram of the slope cross-sectional shape of region P4 in Scheme 2 of this application embodiment;

[0044] Figure 10 This application's second embodiment shows a schematic diagram of the slope cross-sectional shape during longitudinal mining from top to bottom.

[0045] Figure 11 This application provides a schematic diagram of the first-stage south slope morphology and the ballast body morphology in an embodiment of the present application.

[0046] Figure 12 This application provides a schematic diagram of the second-stage south slope morphology and the ballast body morphology in an embodiment of the present application.

[0047] Figure 13 This application provides a schematic diagram of the spatial optimization morphology of the south slope in an embodiment.

[0048] Figure 14 A schematic diagram of the finite element calculation model of this application embodiment;

[0049] Figure 15 Schematic diagrams of numerical simulation results at various tracking distances in the embodiments of this application; (a) is a schematic diagram of numerical simulation results at a tracking distance of 50m, (b) is a schematic diagram of numerical simulation results at a tracking distance of 100m, (c) is a schematic diagram of numerical simulation results at a tracking distance of 200m, (d) is a schematic diagram of numerical simulation results at a tracking distance of 300m, and (e) is a schematic diagram of numerical simulation results at a tracking distance of 400m.

[0050] Figure 16 A schematic diagram of the relationship between tracking distance and slope stability coefficient in an embodiment of this application;

[0051] Figure 17 This application includes a schematic diagram of the final mining boundary of the South Gang.

[0052] Figure 18 A schematic diagram of the initial foundation pit location in the first stage of this application embodiment;

[0053] Figure 19 This application provides a schematic diagram of the engineering location corresponding to the mining of M3 coal in an embodiment.

[0054] Figure 20 This application provides a schematic diagram of the engineering location corresponding to the longitudinal mining of M2 coal seam in this embodiment.

[0055] Figure 21 A schematic diagram of the initial foundation pit location in the second stage of this application embodiment;

[0056] Figure 22 This application embodiment shows the engineering location diagram corresponding to the M1 horizontal mining work section developing to the middle position of the south side;

[0057] Figure 23 The mining progress Gantt chart of this application embodiment. Detailed Implementation

[0058] The specific implementation methods of this application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0059] Example:

[0060] This embodiment proposes a method for the coordinated optimization of slope morphology and mining procedures in open-pit mines with composite coal seams and soft rock, such as... Figure 1 As shown, it includes:

[0061] Step S1: Obtain a representative two-dimensional calculation profile of the slope;

[0062] The process of obtaining a representative two-dimensional calculation profile of the slope includes:

[0063] Step S1.1: Obtain the three-dimensional geological model, slope morphology, and historical geological drilling information;

[0064] Step S1.2: Based on the three-dimensional geological model, slope morphology, and historical geological drilling information, select a representative two-dimensional calculation profile of the slope.

[0065] In this embodiment, a three-dimensional geological model, slope morphology, and historical geological drilling information are first obtained. Secondly, a representative two-dimensional calculation profile of the slope is manually selected. This process is existing technology and will not be described in detail in this embodiment.

[0066] Step S2: Based on the two-dimensional calculation profile of the slope, the coal seams in the slope body are numbered sequentially from top to bottom, and the weak layers in the slope body are numbered sequentially from top to bottom. The location of the weak layers in the slope body is used as the dividing line, and each layer of the slope is numbered from top to bottom to obtain each slope region.

[0067] In this embodiment, based on the two-dimensional calculation profile of the slope, the coal seams within the slope body are numbered sequentially from top to bottom, with the first coal seam numbered M1, the second coal seam numbered M2, ..., until the lowest coal seam is numbered M. i Similarly, the weak layers within the slope are numbered sequentially from top to bottom, with the first weak layer numbered R1, the second weak layer numbered R2, and so on, until the lowest weak layer is numbered R... i Using the location of the weak layer within the slope as the boundary line, each layer of the slope is numbered from top to bottom. The slope area from the R1 weak layer to the ground surface is numbered as slope area P1, the slope area between the R2 weak layer and the R1 weak layer is numbered as slope area P2, and so on. n weak layer to R n-1 The slope region between weak layers is numbered as slope region P. n .

[0068] It should be noted that in this embodiment, not only are the coal seams numbered, but also the weak layers are numbered. The location of the weak layers within the slope is used as the boundary line to number the slope area in order to continue subsequent calculations and obtain the mining parameters and slope cross-sectional morphology of each scheme in two dimensions.

[0069] In this embodiment, taking the south slope of an open-pit coal mine in Inner Mongolia as an example, based on the three-dimensional geological model, slope morphology and previous geological drilling information, a representative two-dimensional calculation profile of the slope is selected. The slope contains three coal seams and four weak layers. The coal seams and weak layers in the slope are numbered sequentially from top to bottom. The first coal seam is numbered M1, the second coal seam is numbered M2, and the third coal seam is numbered M3. The weak layer at the bottom of M1 coal seam is numbered R1, the weak layer at the bottom of M2 coal seam is numbered R2, the weak layer at the top of M3 coal seam is numbered R3, and the weak layer at the bottom of M3 coal seam is numbered R4. Using the weakest layer as the boundary, the slope layers are numbered from top to bottom. The slope area from the R1 weakest layer to the ground surface is numbered P1; the slope area between the R2 weakest layer and the R1 weakest layer is numbered P2; the slope area between the R3 weakest layer and the R2 weakest layer is numbered P3; and the slope area between the R3 weakest layer and the R4 weakest layer is numbered P4. The specific numbering is as follows: Figure 2 As shown.

[0070] Step S3: Based on the open-pit coal mine design, determine the bench form and mining parameters of the transverse mining working side, longitudinal mining working side, end side, and internal spoil heap slope of each coal seam in the composite coal seam;

[0071] In this embodiment, based on the open-pit coal mine mining design, the bench form and mining parameters of each coal seam in the composite coal seam, including the horizontal mining working side, the vertical mining working side, the end side, and the internal spoil heap, are determined as shown in Table 1.

[0072] Table 1 Mining parameters and bench types

[0073]

[0074]

[0075] The mining parameters include: bench height, flatbed width, and bench slope angle.

[0076] In this embodiment, the step form and mining parameters of the horizontal mining working side, vertical mining working side, end side, and internal spoil disposal slope of each coal seam in the composite coal seam are determined. This is existing technology and will not be described in detail in this embodiment.

[0077] Step S4: According to the "Design Code for Open-pit Coal Mines", determine the slope safety reserve coefficient when mining each area with the weak layer as the dividing line based on the slope service life.

[0078] In this embodiment, based on the slope service life and the "Code for Design of Open-Pit Coal Mines" (GB50197-2015), the slope safety reserve coefficient K is determined when mining each area with the weak layer as the boundary. n ;

[0079] In this embodiment, based on the slope service life, the slope safety reserve coefficient K1 of the south slope of the open-pit coal mine from the surface to the R1 weak layer is determined to be 1.10; the slope safety reserve coefficient K2 of the south slope from the surface to the R2 weak layer is 1.10; the slope safety reserve coefficient K3 of the south slope from the surface to the R3 weak layer is 1.10; and the slope safety reserve coefficient K4 of the south slope from the surface to the R4 weak layer is 1.05.

[0080] In this embodiment, the process of determining the slope safety reserve coefficient when mining each area with the weak layer as the dividing line is existing technology and will not be described in detail in this embodiment.

[0081] Step S5: Under the premise of meeting the slope safety reserve coefficient, based on the step form of the longitudinal mining working face, end face, and inner spoil heap slopes and the mining parameters, various slope morphology designs are carried out for each slope area to obtain the mining parameters and slope cross-sectional morphology of each scheme when mining longitudinally from top to bottom, including:

[0082] Step S5.1: Under the premise of meeting the slope safety reserve coefficient, according to the step form of the slope of the longitudinal mining working side, end side, and inner spoil heap, as well as the mining parameters, design multiple slope morphologies for each slope area in the longitudinal mining procedure to obtain multiple slope cross-section morphology schemes.

[0083] In this embodiment, under the premise of meeting the slope safety reserve coefficient, based on the step form of the slope of the longitudinal mining working side, end side, and inner spoil heap, as well as the mining parameters, various slope morphology designs are carried out for each slope area using a longitudinal mining procedure to obtain various slope cross-sectional morphology schemes. This is existing technology and will not be described in detail in this embodiment.

[0084] The number of stages is determined based on the number of weak layers within the slope.

[0085] Based on the number of stages, the Morgenstern method is used to obtain the slope stability coefficient of each region for each slope cross-section scheme. The width of each flat plate is adjusted until the slope stability coefficient of each region meets the constraint conditions. The adjustment of the width of each flat plate is then stopped, thus obtaining the mining parameters and slope cross-section morphology of each scheme when mining vertically from top to bottom.

[0086] The constraint condition is calculated as follows:

[0087] |Fs n -K n | <M

[0088] Among them, Fs n Let M be the slope stability coefficient for the nth stage, and K be a preset threshold value. n This represents the safety reserve coefficient for the nth stage.

[0089] In this embodiment, while ensuring that the slope safety reserve coefficient is met, the weak layer is used as the dividing line, and the mining parameters determined in step 4 are used to process P1, P2, P3, ..., P from top to bottom. n The area was designed with multiple slope morphologies in stages using a longitudinal mining process, and the Morgenstern-Price method was applied to obtain the slope stability coefficient Fs for each stage. n By adjusting the width of each leveling plate, the slope stability coefficient at each stage is maintained within the constraint condition |Fs. n -K n If |<0.005, stop adjusting the width of each flatbed. Determine the mining parameters and slope cross-sectional shape for each scheme when mining longitudinally from top to bottom.

[0090] In this embodiment, the south slope contains four main weak layers from top to bottom. Therefore, the slope is divided into four stages. Scheme 1 involves designing the slope morphology of areas P2, P3, and P4 from top to bottom using a longitudinal mining procedure. The designed slope stability coefficient Fs2 for area P2 is 1.097, and |1.097-1.10|≤0.005. The calculation results are as follows: Figure 3 As shown. The design slope stability coefficient Fs3 for area P3 is 1.098, |1.098-1.10|≤0.005. The calculation results are as follows. Figure 4 As shown. The design slope stability coefficient Fs4 for area P4 is 1.054, and |1.054-1.05|≤0.005. The calculation results are as follows. Figure 5 As shown. Stop adjusting the width of each flatbed. When determining the mining parameters for Scheme 1 (vertical mining from top to bottom), see Table 2. The slope cross-sectional shape is as follows. Figure 6 As shown.

[0091] Table 2 Mining Parameters for Scheme 1 Cross-Section Optimization

[0092]

[0093] Option 2 involves maintaining the existing M1 and M2 coal seams and mining the deeper M3 coal seam from top to bottom, taking into account the four main weak layers and slope areas. The design slope stability coefficient Fs2 for area P2 is 1.103, and |1.103-1.10|≤0.005. The calculation results are as follows: Figure 7 As shown. The design slope stability coefficient Fs3 for area P3 is 1.101, |1.101-1.10|≤0.005. The calculation results are as follows. Figure 8As shown. The design slope stability coefficient Fs4 for area P4 is 1.053, |1.053-1.10|≤0.005. The calculation results are as follows. Figure 9 As shown. Stop adjusting the width of each flatbed. When determining the mining parameters for Scheme Two (vertical mining from top to bottom), see Table 3. The slope cross-sectional shape is as follows. Figure 10 As shown.

[0094] Table 3 Mining parameters for Scheme 2 cross-section optimization

[0095]

[0096]

[0097] Step S6: Based on the mining parameters and slope cross-sectional shape of each scheme during longitudinal mining, and considering the three-dimensional retaining effect of the inner spoil heap on the slope during the tracking and pressing process, optimize each slope area in stages according to the step form of the longitudinal mining working side, the transverse mining working side, the end side, the inner spoil heap, and the mining parameters, and determine the mining parameters, the optimized slope space shape, and the pressing height when transverse mining and longitudinal mining are carried out simultaneously from bottom to top.

[0098] It should be noted that step S5 only considers the two-dimensional shape of the slope and does not consider the three-dimensional retaining effect of the internal spoil disposal site on the slope during the lining process. In the two-dimensional design, only the slope areas P2, P3, and P4 are designed. In steps 6 and 7, when the slope is designed in three dimensions, it is necessary to design not only the P1 area but also the P2, P3, and P4 areas based on the slope cross-sectional shape.

[0099] In this embodiment, based on the optimization results of the slope cross-section shape, multiple slope shape design schemes are combined, and the three-dimensional retaining effect of the internal spoil disposal site on the slope during the tracking and pressing process is considered. The spatial shape parameters of the slope are optimized in stages to determine the mining parameters and the optimized slope spatial shape when horizontal and vertical mining are carried out simultaneously from bottom to top.

[0100] In this embodiment, based on the slope cross-sectional shape optimization results of Scheme 1 and Scheme 2, the three-dimensional retaining effect of the internal spoil disposal site on the slope during the tracking and pressing process is fully considered, and the slope is spatially shaped in two stages for optimization design.

[0101] Phase 1: Based on the optimized cross-sectional parameters of Scheme 2, the coal resources below the +840 level on the south slope will be mined using a transverse mining and internal drainage tracking pressing procedure. At this stage, the morphology of the south slope and the pressing body will be as follows: Figure 11 As shown;

[0102] Phase Two: After the M3 coal seam's ribbed slope is compressed to the +815 level, based on the optimized cross-sectional parameters of Scheme One, longitudinal mining of M2 coal and transverse mining of M1 coal, with internal drainage and ribbed slope tracking, will be carried out. At this time, the morphology of the south slope and the ribbed slope will be as follows: Figure 12 As shown. The final optimized spatial form of the south slope was determined, as follows. Figure 13 As shown, Figures 2 to 13 The horizontal axis represents the slope dip length, and the vertical axis represents the slope elevation.

[0103] Step S7: Establish a finite element calculation model based on the optimized shape of the slope space and the height of the rib, and use three-dimensional numerical simulation software to determine the internal tracking distance of the coal seam during transverse mining;

[0104] In this embodiment, a finite element calculation model is established based on the determined optimal slope spatial shape and lining height. Three-dimensional numerical simulation software is used to determine the tracking distance for transverse coal seam mining.

[0105] In this embodiment, a finite element calculation model is established as follows: Figure 14 As shown, numerical simulation results were obtained using three-dimensional numerical simulation software at tracking distances of 50m, 100m, 200m, 300m, and 400m, respectively. Figure 15 As shown, (a) is a schematic diagram of the numerical simulation results at a tracking distance of 50m, (b) is a schematic diagram of the numerical simulation results at a tracking distance of 100m, (c) is a schematic diagram of the numerical simulation results at a tracking distance of 200m, (d) is a schematic diagram of the numerical simulation results at a tracking distance of 300m, and (e) is a schematic diagram of the numerical simulation results at a tracking distance of 400m. A curve showing the relationship between tracking distance and slope stability coefficient is plotted, as follows. Figure 16 As shown, when the tracking distance is 100m, the slope stability coefficient Fs = 1.10, which just meets the safety reserve coefficient requirement. Considering the impact of engineering disturbances during the mining of resources on the southern slope on slope stability, the tracking distance should be controlled within 50m.

[0106] Step S8: Determine the end slope morphology parameters for each stage based on the current status of the mining area and the optimized slope space.

[0107] The end-side slope morphology parameters for each stage include: optimized horizontal step heights, optimized flatbed widths, and optimized step slope angles. Using these optimized parameters, the final mining boundary of the end-side slope is determined.

[0108] The process of determining the height of each horizontal bench, the width of the flat plate, and the slope angle of the bench based on the current status of the mining area and the optimized shape of the slope space, and determining the morphological parameters of the end slope at each stage, is existing technology and will not be described in detail in this application.

[0109] In this embodiment, using the current mining status of the open-pit coal mine in November 2024 as the base map, and combining the optimization results of the cross-section and spatial morphological parameters of the south slope to the boundary, the final mining boundary of the south slope is determined as follows: Figure 17 As shown in Table 4, the height of each horizontal step, the width of the flat plate, and the slope angle of the step after the final mining boundary of the South Slope are optimized.

[0110] Table 4. Parameters of each level step after optimization of the final mining boundary of the end face:

[0111]

[0112] Step S9: Based on the current status of the mining area and the end slope morphology parameters of each stage, refine the mining stages. Based on the tracing distance of the coal seam's transverse mining, draw a plan view of the engineering location for each stage. Also, draw a Gantt chart of the slope mining progress according to the coal volume of each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining, including:

[0113] Step S9.1: Refine the mining stages based on the current status of the mining area and the morphological parameters of the end slopes at each stage;

[0114] Step S9.2: Based on the tracking distance of the coal seam transverse mining internal dump, the location of the mining project, the bench form of the transverse mining working side, the longitudinal mining working side, the end side, and the internal dump site, as well as the mining parameters, draw a plan view of the project location at each stage;

[0115] A Gantt chart of the slope mining progress is drawn based on the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining.

[0116] In this embodiment, the mining stages are refined based on the current status of the mining area and the morphological parameters of the end slopes at each stage. A plan view of the engineering location at each stage is drawn, and a Gantt chart of the slope mining progress is drawn based on the coal volume and mining sequence at each stage to guide subsequent open-pit coal mining. The drawing of the plan view and the Gantt chart is existing technology and will not be described in detail in this embodiment.

[0117] In this embodiment, the first stage involves lowering the depth of the trench from the west side of the south slope to form a horizontal mining working face for the deep mining of M3 coal seam. The corresponding initial pit location is as follows: Figure 18 As shown, as the deep M3 cross-mining working face advances eastward, a localized rib-shrinking body gradually forms and maintains a 50m tracking distance from the deep M3 cross-mining working face. When the deep M3 cross-mining working face advances to the middle of the south rib, the shallow M3 coal resources at the +815 to +795 levels of the south rib are ready for mining, and the shallow M3 coal at the +815 to +795 levels can be mined. The corresponding engineering locations are shown in the figure. Figure 19As shown. When the first stage of the M3 coal group's transverse mining work reached the middle of the south slope, the deep internal drainage slope had already provided three-dimensional support for the south slope. The south slope control mining procedure then entered the second stage, involving the longitudinal mining of the upper M2 coal seam on the south slope. The corresponding engineering locations are shown in the figure. Figure 20 As shown in the diagram, with the longitudinal mining of M2 coal reaching its boundary, M1 coal can be horizontally mined and backfilled. The initial location of the foundation pit for the horizontal mining of M1 is as follows: Figure 21 As shown. With the M1 horizontal mining working face advancing eastward, the corresponding engineering location when the M1 horizontal mining working face reaches the central part of the southern slope is as follows. Figure 22 As shown, with the horizontal mining of each coal seam advancing to the boundary, the coal resources in the south sloping area have been fully recovered. A Gantt chart of the slope mining progress is drawn based on the coal volume and mining sequence at each stage, as shown below. Figure 23 As shown.

[0118] This embodiment proposes a method for the coordinated optimization of slope morphology and mining procedures in open-pit mines with composite coal seams and soft rock. Two-dimensional and three-dimensional numerical simulation software are used to design the slope morphology, and the coal resources covered by the end slopes are recovered to the maximum extent, thereby improving the coal resource recovery rate. Generally, when using 2D or 3D numerical simulation software to design the shape of a slope, the final shape of the slope is usually designed in 2D. However, this embodiment considers both 2D and 3D aspects and the mining procedure during the slope design process. Specifically, it starts by numbering the weak layers and slope areas, using the weak layers as boundaries to determine the slope safety reserve coefficient for each mining area as a standard to measure the feasibility of the scheme. In the 2D design, the mining parameters and slope cross-sectional shape of each scheme are determined during the top-down longitudinal mining. The three-dimensional retaining effect of the internal dumping site on the slope is optimized in stages for each slope area. The mining parameters, slope spatial optimization shape, and dumping height are determined when the bottom-up transverse mining and longitudinal mining are carried out simultaneously. Then, the internal dumping tracking distance of the coal seam in the 3D finite element calculation model is determined. Based on the internal dumping tracking distance of the coal seam in the transverse mining, the engineering location plan of each stage is drawn. And according to the coal volume of each stage and the mining sequence of each scheme, the slope mining progress Gantt chart is drawn to guide the subsequent open-pit coal mining. Through the above series of processes, this embodiment improves the recovery rate of coal resources.

[0119] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0120] The scope of protection of this application is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the scope and spirit of this disclosure. If such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A method for synergistic optimization of slope morphology and mining procedures in open-pit mines with composite coal seams and soft rock, characterized in that, include: Obtain a representative two-dimensional calculation profile of the slope; Based on the two-dimensional calculation profile of the slope, the coal seams in the slope body are numbered sequentially from top to bottom, and the weak layers in the slope body are numbered sequentially from top to bottom. The location of the weak layers in the slope body is used as the dividing line, and each layer of the slope is numbered from top to bottom to obtain each slope region. Based on the open-pit coal mine design, determine the bench form and mining parameters of the transverse mining working side, longitudinal mining working side, end side, and internal spoil heap slope of each coal seam in the composite coal seam; According to the "Design Code for Open-pit Coal Mines", the slope safety reserve coefficient is determined based on the slope service life when mining each area with the weak layer as the dividing line. Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slope of the longitudinal mining working side, end side, and inner spoil disposal site, as well as the mining parameters, various slope morphology designs are carried out for each slope area to obtain the mining parameters and slope cross-sectional morphology of each scheme when mining longitudinally from top to bottom. Based on the mining parameters and slope cross-sectional shape of each scheme during top-down longitudinal mining, and considering the three-dimensional retaining effect of the internal spoil heap on the slope during the lining process, the slope areas are optimized in stages to determine the mining parameters, slope spatial optimization shape, and lining height when bottom-up transverse mining and longitudinal mining are carried out simultaneously. A finite element calculation model was established based on the optimized shape of the slope space and the height of the rib, and the three-dimensional numerical simulation software was used to determine the internal discharge tracking distance of the coal seam in the transverse mining. Based on the current status of the mining area and the optimized shape of the slope space, the morphological parameters of the end slope at each stage are determined. Based on the current status of the mining area and the morphological parameters of the end slopes at each stage, the mining stages are refined. Based on the tracing distance of the coal seam in the transverse mining, a plan view of the engineering location at each stage is drawn. A Gantt chart of the slope mining progress is drawn according to the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining.

2. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, The process of obtaining a representative two-dimensional calculation profile of the slope includes: Obtain three-dimensional geological models, slope morphology, and historical geological drilling information; Based on the three-dimensional geological model, slope morphology, and historical geological drilling information, representative two-dimensional calculation profiles of the slope are selected.

3. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, The location of weak layers within the slope body is used as the dividing line. Each layer of the slope is numbered from top to bottom to obtain each slope region, including: R1 weak layer to the surface of the slope region is numbered as the slope region P1, R2 weak layer to R1 weak layer between the slope region is numbered as the slope region P2, and so on, R n weak layer to R n-1 layer weak layer between the slope region is numbered as the slope region P n .

4. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, The mining parameters include: bench height, flatbed width, and bench slope angle.

5. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slopes of the longitudinal mining working face, end face, and internal spoil heap, as well as the mining parameters, various slope morphology designs are carried out for each slope area to obtain the mining parameters and slope cross-sectional morphology of each scheme when mining longitudinally from top to bottom, including: Under the premise of meeting the slope safety reserve coefficient, based on the step form of the slope of the longitudinal mining working side, end side, and inner spoil dump, as well as the mining parameters, various slope morphology designs are carried out for each slope area using the longitudinal mining procedure to obtain various slope cross-section morphology schemes. The number of stages is determined based on the number of weak layers within the slope. Based on the number of stages, the Morgenstern method is used to obtain the slope stability coefficient of each region for each slope cross-section scheme. The width of each flat plate is adjusted until the slope stability coefficient of each region meets the constraint conditions. The adjustment of the width of each flat plate is then stopped, and the mining parameters and slope cross-section morphology of each scheme are obtained when mining vertically from top to bottom.

6. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 5, characterized in that, The constraint condition is calculated as follows: |Fs n -K n |<M Among them, Fs n Let M be the slope stability coefficient for the nth stage, and K be a preset threshold value. n This represents the safety reserve coefficient for the nth stage.

7. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, The morphological parameters of the end slope at each stage include: the optimized height of each horizontal step, the optimized width of the flat plate, and the optimized slope angle of the step.

8. The method for collaborative optimization of slope morphology and mining procedure in composite coal seam soft rock open-pit mines according to claim 1, characterized in that, The mining stages are refined based on the current status of the mining area and the morphological parameters of the end slopes at each stage. Based on the tracing distance of the coal seam's transverse mining, a plan view of the engineering location for each stage is drawn. Furthermore, a Gantt chart of the slope mining progress is drawn according to the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining, including: The mining stages are refined based on the current status of the mining site and the morphological parameters of the end slopes at each stage. Based on the tracking distance of the coal seam's transverse mining internal dump, the location of the mining project, the bench form of the transverse mining working side, the longitudinal mining working side, the end side, the internal dump site, and the mining parameters, draw a plan view of the project location at each stage. A Gantt chart of the slope mining progress is drawn based on the coal volume at each stage and the mining sequence of each scheme to guide subsequent open-pit coal mining.

Images