Composite coal seam soft rock strip mine slope form and mining program collaborative optimization method

Abstract

The invention provides a composite coal seam soft rock strip mine side slope form and mining program collaborative optimization method, belongs to the technical field of open pit coal mining, and aims at performing various side slope form designs on each side slope area by using two-dimensional numerical simulation software on the premise of meeting a side slope safety reserve coefficient. Slope mining parameters and slope section forms of all the schemes during vertical mining from top to bottom are obtained; slope mining parameters and slope section forms of all schemes during longitudinal mining from top to bottom are synthesized, the three-dimensional retaining effect on the slope in the inner waste dump tracking and slope pressing process is considered, all slope areas are optimized in a staged mode, the coal seam transverse mining inner drainage tracking distance is determined through three-dimensional numerical simulation software, and the coal seam transverse mining inner drainage tracking distance is determined. Finally, mining parameters, slope space optimization forms and slope pressing heights when transverse mining and longitudinal mining are carried out at the same time from bottom to top are determined; according to the method, end slope pressing coal resources are recycled to the maximum extent, open pit coal mining operation is guided, and the coal resource recycling rate is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of open-pit coal mining, and in particular relates to a method for collaboratively optimizing the slope morphology and mining procedures of a soft rock open-pit mine with a composite coal seam. Background Art

[0002] In the existing technology, the optimization of slope morphology and mining procedures for composite coal seam soft rock open-pit mines usually has the following advantages: first, it can quickly release and fully utilize the internal drainage space, shorten the transportation distance, reduce the external drainage cost, effectively reduce the production cost, and improve the economic benefits of the open-pit mine; second, it can shorten the exposure space and time of the weak layer of the slope of the composite coal seam open-pit mine and improve the stability of the slope; third, it can increase the recovery of coal resources in the open-pit mine and extend the service life of the mining area.

[0003] For example, patent CN118895974A discloses a method for mining a composite coal seam by forced drainage and steep slope. The method mines the composite coal seam in different zones, provides parameters for the horizontal working slope, end slope and inner dumping yard, the safe distance between the horizontal working slope and the inner dumping yard of multiple coal seams, and a method for determining the mining process, guides the mining operation of the open-pit mine by forced drainage and steep slope, and improves the mining efficiency and quality. Patent CN112855162A discloses a method for mining the upper coal seam of the end slope of a composite coal seam open-pit mine by leaning against the slope. The method uses the inner dumping yard step to form a working space for the arrangement of mining equipment. , and use the inner dump step working flat plate to carry out the segmented recovery operation of the upper coal seam covering the end wall resources, and mine the upper coal seam, the coal seam and the interbedded gangue between the mining level together, and point out that the length of the end wall coal recovered in the advancement direction is equal to the width of the dump flat plate; Patent CN113742949B discloses a method for determining the mining width of high-position coal seams in composite coal seam open-pit mines. This method adjusts the width of each flat plate between coal seams, calculates the difference between the coal seam before and after the flat plate width is adjusted, finds the relationship between the flat plate width and the mining width, and mines the high-position coal seam by using the support effect of the inner row of horizontal mining.

[0004] These patents all focus on open-pit mining methods and upper coal seam recovery widths, but fail to consider the relationship between soft rock open-pit coal mine slope morphology and mining procedures. This leads to an imbalance between the release of waste space and slope stability control. Therefore, there is an urgent need to develop a method for collaboratively optimizing slope morphology and mining procedures in soft rock open-pit mines with composite coal seams to provide technical support for subsequent open-pit coal mining. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, this application proposes a method for collaborative optimization of slope morphology and mining procedures in composite coal seam soft rock open-pit mines, including:

[0006] Obtain representative two-dimensional slope calculation profiles;

[0007] Based on the two-dimensional calculated section of the slope, the coal seams in the slope body are numbered from top to bottom, the weak layers in the slope body are numbered from top to bottom, and the occurrence position of the weak layers in the slope body is used as the dividing line to number the layers of the slope from top to bottom to obtain each slope area;

[0008] According to the open-pit coal mining design, determine the step form and mining parameters of the horizontal working side, vertical working side, end side, and inner dump slope of each coal seam in the composite coal seam;

[0009] According to the Design Code for Open-Pit Mines in the Coal Industry, the slope safety reserve coefficient is determined based on the service life of the slope when mining each area with the weak layer as the boundary;

[0010] Under the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed for each slope area according to the step form of the vertical mining working side, end side, and inner dump slope and mining parameters, and the mining parameters and slope cross-sectional shapes of each scheme when mining from top to bottom are obtained;

[0011] By comprehensively considering the mining parameters and slope cross-sectional morphology of each top-down longitudinal mining scheme and the three-dimensional retaining effect of the inner dump on the slope during the tracking and walling process, each slope area is optimized in stages to determine the mining parameters, slope spatial optimization morphology, and walling height when horizontal and longitudinal mining are carried out simultaneously from bottom to top.

[0012] According to the optimized shape of slope space and the height of the pressure wall, a finite element calculation model was established, and the inner row tracking distance of the horizontal mining of the coal seam was determined using three-dimensional numerical simulation software.

[0013] According to the current situation of the stope and the optimized shape of the slope space, determine the shape parameters of the end slope at each stage;

[0014] The mining stages are refined according to the current status of the mining site and the morphological parameters of the end slopes at each stage. Based on the internal tracking distance of the horizontal mining of the coal seam, a plan of the project 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 plan to guide subsequent open-pit coal mining.

[0015] The method of obtaining a representative two-dimensional slope calculation profile 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, a representative two-dimensional slope calculation section is selected.

[0018] The above method uses the location of the weak layer in the slope as the dividing line, and numbers the layers of the slope from top to bottom to obtain the slope areas, including:

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

[0020] The mining parameters include: step height, flat plate width and step slope angle.

[0021] On the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed on each slope area according to the step form of the vertical mining working side, end side, and inner dump slope and mining parameters, and the mining parameters and slope cross-sectional shapes of each scheme during top-down vertical mining are obtained, including:

[0022] Under the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed on each slope area using a longitudinal mining procedure according to the step form of the longitudinal mining working side, end side, and inner dump slope and mining parameters, thereby obtaining various slope cross-sectional shape schemes;

[0023] The number of stages is determined based on the number of weak layers in the slope body;

[0024] According to the number of stages, for each slope cross-sectional morphology scheme, the Morgenstern method is used to obtain the slope stability coefficient of each area, and the width of each flat plate is adjusted until the slope stability coefficient of each area meets the constraint conditions. The adjustment of the width of each flat plate is stopped, and the mining parameters and slope cross-sectional morphology of each scheme during top-down longitudinal mining are obtained.

[0025] The constraint conditions are calculated as follows:

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

[0027] Among them, Fs n is the slope stability coefficient at stage n, M is the preset threshold, K n is the safety reserve factor of the nth stage.

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

[0029] The mining stages are refined according to the current status of the stope and the parameters of the end slope shape at each stage. Based on the internal tracking distance of the horizontal mining of the coal seam, a plan of the project 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 plan to guide subsequent open-pit coal mining, including:

[0030] Refine the mining stages according to the current situation of the stope and the parameters of the end and side slopes at each stage;

[0031] Based on the internal row tracking distance of horizontal mining of coal seams, mining project location, horizontal mining working side, vertical mining working side, end side, step form of internal dumping area and mining parameters, draw the plan of project location at each stage;

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

[0033] Beneficial effects:

[0034] This application proposes a collaborative optimization method for slope morphology and mining procedures in soft rock open-pit mines with composite coal seams. Based on the stability of the end-wall slopes, this application comprehensively considers the mining parameters, tracking distances, and development sequence of the internal dump and the horizontal and vertical working sides of each coal seam. Two-dimensional and three-dimensional numerical simulation software is used to design the slope morphology and maximize the recovery of coal resources buried under the end-walls. The core of this method is to establish a collaborative optimization method for slope morphology and mining procedures to guide open-pit coal mining operations and improve coal resource recovery. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0036] Figure 2 Schematic diagram of the numbering of coal seams, weak layers and slope areas in the embodiment of the present application;

[0037] Figure 3 Schematic diagram of the slope cross-section in the P2 area of the first embodiment of the present application;

[0038] Figure 4 Schematic diagram of the slope cross-section in the P3 area of the first embodiment of the present application;

[0039] Figure 5 Schematic diagram of the slope cross-section in the P4 area of Scheme 1 of the present application;

[0040] Figure 6 Schematic diagram of the cross-section of the slope during top-down longitudinal mining in Scheme 1 of the embodiment of the present application;

[0041] Figure 7 Schematic diagram of the slope cross-section in the P2 area of the second embodiment of the present application;

[0042] Figure 8 Schematic diagram of the slope cross-section in the P3 area of the second embodiment of the present application;

[0043] Figure 9 Schematic diagram of the slope cross-section in the P4 area of the second embodiment of the present application;

[0044] Figure 10 Schematic diagram of the cross-section of the slope during top-down longitudinal mining in Scheme 2 of the embodiment of the present application;

[0045] Figure 11 Schematic diagram of the first stage south side slope and pressure side body shape of the embodiment of the present application;

[0046] Figure 12 Schematic diagram of the south side slope and pressure body shape in the second stage of the embodiment of the present application;

[0047] Figure 13 Schematic diagram of the spatial optimization of the south slope of the embodiment of the present application;

[0048] Figure 14 Schematic diagram of the finite element calculation model of the embodiment of the present application;

[0049] Figure 15 Schematic diagrams of numerical simulation results at various tracking distances for the embodiments of the present application; (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;

[0050] Figure 16 A schematic diagram of a curve showing the relationship between tracking distance and slope stability coefficient according to an embodiment of the present application;

[0051] Figure 17 Schematic diagram of the final mining boundary of the South Bang in the embodiment of the present application;

[0052] Figure 18 Schematic diagram of the initial foundation pit position in the first stage of the embodiment of the present application;

[0053] Figure 19 Schematic diagram of the engineering location corresponding to the M3 coal mining in the embodiment of the present application;

[0054] Figure 20 Schematic diagram of the engineering location corresponding to the longitudinal mining of M2 coal in the embodiment of the present application;

[0055] Figure 21 Schematic diagram of the initial foundation pit position in the second stage of the embodiment of the present application;

[0056] Figure 22 A schematic diagram of the corresponding engineering position when the M1 horizontal mining working section of the embodiment of the present application develops to the middle position of the south section;

[0057] Figure 23 Gantt chart of mining progress in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The specific implementation of the present application is further described in detail below with reference to the accompanying drawings and examples.

[0059] Example:

[0060] This embodiment proposes a method for collaboratively optimizing the slope morphology and mining procedures of a composite coal seam soft rock open-pit mine. Figure 1 Shown, including:

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

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

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

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

[0065] In this embodiment, a 3D geological model, slope morphology, and historical geological drilling information are first obtained. Next, a representative 2D slope profile is manually selected. This process is conventional and will not be further described in this embodiment.

[0066] Step S2: Based on the two-dimensional calculated 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 occurrence position 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 area;

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

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

[0069] In this embodiment, taking the southern slope of an open-pit coal mine in Inner Mongolia as an example, a representative two-dimensional calculation profile of the slope is selected based on the three-dimensional geological model, slope morphology and previous geological drilling information. The slope has a total of three coal layers and four weak layers. The coal seams and weak layers in the slope body are numbered from top to bottom, the first coal layer is numbered M1, the second coal layer is numbered M2, and the third coal layer is numbered M3. The weak layer of the M1 coal bottom plate is numbered R1, the weak layer of the M2 coal bottom plate is numbered R2, the weak layer of the M3 coal roof is numbered R3 and the weak layer of the M3 coal bottom plate is numbered R4. Taking the weak layer as the dividing line, the slope layers are numbered from top to bottom. The slope area from the weak layer R1 to the ground surface is numbered P1, the slope area between the weak layer R2 and the weak layer R1 is numbered P2, the slope area between the weak layer R3 and the weak layer R2 is numbered P3, and the slope area between the weak layer R3 and the weak layer R4 is numbered P4. The specific numbers are as follows: Figure 2 shown.

[0070] Step S3: Determine the step form and mining parameters of the horizontal working side, vertical working side, end side, and inner dump slope of each coal seam in the composite coal seam according to the open-pit coal mining design;

[0071] In this embodiment, according to the open-pit coal mining design, the step forms and mining parameters of the horizontal working side, vertical working side, end side and inner dump of each coal seam in the composite coal seam are determined as shown in Table 1.

[0072] Table 1 Mining parameters and step forms

[0073]

[0074]

[0075] The mining parameters include step height, flat plate width and step slope angle.

[0076] In this embodiment, determining the step form and mining parameters of the horizontal mining working side, vertical mining working side, end side, and inner dump slope of each coal seam in the composite coal seam belongs to the existing technology and will not be repeated in this embodiment.

[0077] Step S4: According to the Design Code for Open-Pit Mines in the Coal Industry and based on the service life of the slope, determine the slope safety reserve coefficient when mining each area with the weak layer as the boundary line;

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

[0079] In this embodiment, the slope safety reserve coefficient K1 from the surface of the south slope to the R1 weak layer area of the open-pit coal mine is determined to be 1.10 based on the slope service life; the slope safety reserve coefficient K2 from the surface of the south slope to the R2 weak layer area is 1.10; the slope safety reserve coefficient K3 from the surface of the south slope to the R3 weak layer area is 1.10; and the slope safety reserve coefficient K4 from the surface of the south slope to the R4 weak layer area 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 boundary line belongs to the existing technology and will not be repeated in this embodiment.

[0081] Step S5: Under the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed on the slope areas according to the step forms and mining parameters of the vertical mining working side, end side, and inner dump slopes, and the mining parameters and slope cross-sectional shapes of each scheme during top-down vertical mining are obtained, including:

[0082] Step S5.1: Under the premise of satisfying the slope safety reserve coefficient, various slope morphology designs are performed for each slope area using a longitudinal mining procedure based on the step form of the longitudinal mining working side, end side, and inner dump slopes and mining parameters, thereby obtaining various slope cross-sectional morphology schemes;

[0083] In this embodiment, on the premise of satisfying the slope safety reserve coefficient, various slope morphology designs are performed on each slope area using a longitudinal mining procedure according to the step form of the longitudinal mining working side, end side, and inner spoil dump slope, as well as the mining parameters, to obtain various slope cross-sectional morphology schemes, which belongs to the existing technology and will not be repeated in this embodiment.

[0084] The number of stages is determined based on the number of weak layers in the slope body;

[0085] According to the number of stages, for each slope cross-sectional morphology scheme, the Morgenstern method is used to obtain the slope stability coefficient of each area, and the width of each flat plate is adjusted until the slope stability coefficient of each area meets the constraint conditions. The adjustment of the width of each flat plate is stopped, and the mining parameters and slope cross-sectional morphology of each scheme during top-down longitudinal mining are obtained.

[0086] The constraint conditions are calculated as follows:

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

[0088] Among them, Fs n is the slope stability coefficient at stage n, M is the preset threshold, K n is the safety reserve factor of the nth stage.

[0089] In this embodiment, under the premise of 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 mine P1, P2, P3, ..., P from top to bottom. n The area is designed with various slope forms in stages using a longitudinal mining procedure, and the Morgenstern-Price method is used to obtain the slope stability coefficient Fs at each stage. n By adjusting the width of each plate, the slope stability coefficient at each stage meets the constraint condition |Fs n -K n |<0.005, stop adjusting the width of each flat plate. Determine the mining parameters and slope cross-section shape of each plan when mining from top to bottom.

[0090] In this example, the south slope has four main weak layers from top to bottom, so the slope is divided into four stages. Scheme 1 is to design the slope shape of P2, P3, and P4 areas from top to bottom using a vertical mining procedure. The slope stability coefficient Fs2 of the P2 area is 1.097, and the calculation results of |1.097-1.10|≤0.005 are as follows: Figure 3 The design slope stability coefficient Fs3 of the P3 area is 1.098, and the calculation results of |1.098-1.10|≤0.005 are as follows. Figure 4 The design slope stability coefficient Fs4 of the P4 area is 1.054, and the calculation results of |1.054-1.05|≤0.005 are as follows. Figure 5 Stop adjusting the width of each flat plate and determine the mining parameters of Scheme 1 when mining from top to bottom as shown in Table 2. The cross-sectional shape of the slope is as shown in Figure 6 shown.

[0091] Table 2 Mining parameters of optimized cross-section shape of Scheme 1

[0092]

[0093] The second option is to keep the M1 and M2 coal groups as they are, and mine the deep M3 coal group from top to bottom, taking into account the four main weak layers and slope areas. The slope stability coefficient Fs2 of the P2 area is designed to be 1.103, and the calculation results are as follows: |1.103-1.10|≤0.005 Figure 7 The design slope stability coefficient Fs3 of the P3 area is 1.101, and the calculation results of |1.101-1.10|≤0.005 are as follows. Figure 8The design slope stability coefficient Fs4 of the P4 area is 1.053, and the calculation results of |1.053-1.10|≤0.005 are as follows. Figure 9 Stop adjusting the width of each flat plate and determine the mining parameters of the second plan from top to bottom as shown in Table 3. The cross-sectional shape of the slope is as shown in Figure 10 shown.

[0094] Table 3 Mining parameters of optimized cross-section shape of Scheme 2

[0095]

[0096]

[0097] Step S6: Comprehensively considering the mining parameters and slope cross-sectional morphology of each vertical mining scheme, taking into account the three-dimensional support effect of the inner dump on the slope during the tracking and pressure wall process, and based on the step forms of the vertical mining working wall, horizontal mining working wall, end wall, and inner dump, as well as the mining parameters, each slope area is optimized in stages to determine the mining parameters, slope spatial optimization morphology, and pressure wall height when horizontal mining and vertical 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 support effect of the slope during the tracking and pressing process of the inner spoil field. During the two-dimensional design, only the slope areas P2, P3, and P4 are designed. When the slope is designed in three dimensions in steps 6 and 7, it is necessary to design not only the P1 area but also the P2, P3, and P4 areas based on the cross-sectional shape of the slope.

[0099] In this embodiment, based on the optimization results of the slope cross-sectional morphology, a variety of slope morphology design schemes are combined, and the three-dimensional support effect of the slope during the tracking and pressing process of the inner spoil field is taken into consideration. The spatial morphology parameters of the slope are optimized in stages, and the mining parameters and the slope spatial optimization morphology are determined when horizontal mining and vertical mining are carried out simultaneously from bottom to top.

[0100] In this embodiment, based on the optimization results of the slope cross-section of Scheme 1 and Scheme 2, the three-dimensional support effect of the slope during the tracking and pressing process of the inner spoil field is fully considered, and the spatial morphology optimization design of the slope is carried out in two stages.

[0101] Phase I: Based on the cross-sectional shape optimization parameters of Scheme II, the coal resources below the +840 level of the south slope are mined using the mining procedure of horizontal mining, inner row tracking and pressure wall tracking. At this time, the shape of the south slope and the pressure wall body is as follows: Figure 11 As shown;

[0102] The second stage: When the deep M3 coal group pressure wall is pressed to the +815 level, based on the cross-section shape optimization parameters of Scheme 1, the M2 coal is mined vertically and the M1 coal is mined horizontally. The mining procedure of the inner row tracking pressure wall is constructed. At this time, the shape of the south slope and the pressure wall body is as follows: Figure 12 Finally, the optimal spatial form of the south slope is determined, as shown in Figure 13 As shown, Figures 2 to 13 The horizontal axis represents the slope inclination length, and the vertical axis represents the slope elevation.

[0103] Step S7: establishing a finite element calculation model based on the slope spatial optimization shape and the pressure wall height, and using three-dimensional numerical simulation software to determine the inner row tracking distance of the coal seam horizontal mining;

[0104] In this embodiment, a finite element calculation model is established based on the determination of the optimized spatial shape of the slope and the height of the pressure wall. Three-dimensional numerical simulation software is used to determine the inner row tracking distance of the horizontal mining of the coal seam;

[0105] In this embodiment, a finite element calculation model is established as follows: Figure 14 As shown in the figure, the three-dimensional numerical simulation software is used to obtain the numerical simulation results at tracking distances of 50m, 100m, 200m, 300m, and 400m respectively. Figure 15 As shown in the figure, (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. The relationship curve between the tracking distance and the slope stability coefficient is drawn, as shown in the figure. Figure 16 As shown in the figure, when the tracking distance is 100m, the slope stability coefficient Fs = 1.10, which just meets the safety reserve factor requirement. Taking into account the impact of engineering disturbances on slope stability during the mining of the Nanbang overburden resources, it is determined that the tracking distance should be controlled within 50m.

[0106] Step S8: Determine the end slope shape parameters at each stage according to the current situation of the stope and the optimized shape of the slope space;

[0107] The slope morphology parameters for each stage include the optimized horizontal step height, optimized flat plate width, and optimized step slope angle. The final mining boundary of the end wall is determined using these optimized horizontal step heights, optimized flat plate width, and optimized step slope angle.

[0108] The process of determining the height of each horizontal step, the width of the flat plate and the slope angle according to the current status of the mining site and the optimized shape of the slope space, and determining the shape parameters of the end slopes at each stage belongs to the existing technology and will not be repeated in this application.

[0109] In this embodiment, the mining status of the open-pit coal mine in November 2024 is used as the base map, and the optimization results of the slope section from the south bank to the boundary and the spatial morphological parameters are combined to determine the final mining boundary of the south bank. 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 ridge is optimized;

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

[0111]

[0112] Step S9: Refine the mining stages according to the current status of the stope and the parameters of the end slope shape at each stage. Draw a plan of the project location at each stage based on the internal row tracking distance of the horizontal mining of the coal seam. Draw a Gantt chart of the slope mining progress according to the coal quantity at each stage and the mining sequence of each plan to guide subsequent open-pit coal mining, including:

[0113] Step S9.1: Refine the mining stages according to the current situation of the stope and the parameters of the end and side slopes at each stage;

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

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

[0116] In this embodiment, the mining stages are refined according to the current status of the mining site and the morphological parameters of the end slopes at each stage, a plan view of the project location at each stage is drawn, and a Gantt chart of the slope mining progress is drawn according to the coal quantity and mining sequence at each stage to guide subsequent open-pit coal mining. The drawing of the plan view and Gantt chart belongs to the existing technology and will not be repeated in this embodiment.

[0117] In this embodiment, the first stage is to reduce the depth of the coal by pulling the trench from the west side of the south wall to form a horizontal working wall to mine the deep M3 coal. The corresponding initial foundation pit position is as follows: Figure 18 As the deep M3 horizontal mining working wall advances eastward, a local pressure wall gradually forms and always maintains a tracking distance of 50m with the deep M3 horizontal mining working wall. When the deep M3 horizontal mining working wall advances to the middle of the south wall, the shallow M3 coal resources at the +815 to +795 levels of the south wall are ready for mining. The shallow M3 coal at the +815 to +795 levels can be mined. The corresponding engineering location is shown in the figure below. Figure 19As shown in the figure. When the horizontal mining work of the M3 coal group in the first phase developed to the middle of the south slope, the deep internal pressure relief wall body had played a three-dimensional supporting role on the south slope. The south slope control mining process entered the second phase, and the M2 coal in the upper part of the south slope was mined longitudinally. The corresponding engineering location is shown in the figure. Figure 20 As the M2 coal is mined vertically to the boundary, the M1 coal can be mined horizontally for replacement and filling. The initial foundation pit position of M1 horizontal mining is as follows: Figure 21 As the M1 horizontal mining work advances eastward, when the M1 horizontal mining work develops to the middle of the south bank, the corresponding project location is as follows. Figure 22 As the horizontal mining work of each coal seam advances to the boundary, the coal resources of the southern slope are recovered. According to the coal quantity and mining sequence of each stage, a Gantt chart of the slope mining progress is drawn as shown in the figure below. Figure 23 shown.

[0118] This embodiment proposes a method for collaboratively optimizing the slope morphology and mining procedures of a soft rock open-pit mine in a composite coal seam. Two-dimensional and three-dimensional numerical simulation software is used to design the slope morphology, maximize the recovery of coal resources covered by the end walls, and improve the recovery rate of coal resources. Generally speaking, if two-dimensional or three-dimensional numerical simulation software is considered for slope morphology design, the final shape of the slope is usually designed in two dimensions. However, this embodiment considers two-dimensional plus three-dimensional and the mining procedure in the slope design process. Specifically, it starts from numbering the weak layers and slope areas, and uses the weak layers as the dividing line to determine the slope safety reserve coefficient of each mining area as a standard for measuring the feasibility of the scheme, and then to the mining parameters and slope cross-sectional morphology of each scheme during top-down longitudinal mining in the two-dimensional design, and the three-dimensional support effect of the slope on the slope during the tracking and pressure wall of the inner spoil dump is optimized in stages for each slope area, and the mining parameters, slope spatial optimization shape and pressure wall height are determined when bottom-up horizontal mining and vertical mining are carried out simultaneously, and then the internal tracking distance of the coal seam horizontal mining is determined in the three-dimensional finite element calculation model, and based on the internal tracking distance of the coal seam horizontal mining, a plan view of the project location at each stage is drawn, and 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. 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, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0120] The scope of protection of this application is not limited to the above-described embodiments. Obviously, those skilled in the art may 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, the disclosure is intended to include such modifications and variations.

Claims

1. A method for collaborative optimization of slope morphology and mining procedures in a soft rock open-pit mine with composite coal seams, characterized in that: include: Obtain representative two-dimensional slope calculation profiles; Based on the two-dimensional calculated section of the slope, the coal seams in the slope body are numbered from top to bottom, the weak layers in the slope body are numbered from top to bottom, and the occurrence position of the weak layers in the slope body is used as the dividing line to number the layers of the slope from top to bottom to obtain each slope area; According to the open-pit coal mining design, determine the step form and mining parameters of the horizontal working side, vertical working side, end side, and inner dump slope of each coal seam in the composite coal seam; According to the Design Code for Open-Pit Mines in the Coal Industry, the slope safety reserve coefficient is determined based on the service life of the slope when mining each area with the weak layer as the boundary; Under the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed for each slope area according to the step form of the vertical mining working side, end side, and inner dump slope and mining parameters, and the mining parameters and slope cross-sectional shapes of each scheme when mining from top to bottom are obtained; By comprehensively considering the mining parameters and slope cross-sectional morphology of each top-down longitudinal mining scheme and the three-dimensional retaining effect of the inner dump on the slope during the tracking and walling process, each slope area is optimized in stages to determine the mining parameters, slope spatial optimization morphology, and walling height when horizontal and longitudinal mining are carried out simultaneously from bottom to top. According to the optimized shape of slope space and the height of the pressure wall, a finite element calculation model was established, and the inner row tracking distance of the horizontal mining of the coal seam was determined using three-dimensional numerical simulation software. According to the current situation of the stope and the optimized shape of the slope space, determine the shape parameters of the end slope at each stage; The mining stages are refined according to the current status of the mining site and the morphological parameters of the end slopes at each stage. Based on the internal tracking distance of the horizontal mining of the coal seam, a plan of the project 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 plan to guide subsequent open-pit coal mining.

2. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 1, characterized in that: The method of obtaining a representative two-dimensional slope calculation profile 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, a representative two-dimensional slope calculation section is selected.

3. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 1, characterized in that: The above method uses the location of the weak layer in the slope as the dividing line, and numbers the layers of the slope from top to bottom to obtain the slope areas, including: The slope area from the weak layer R1 to the ground surface is numbered as slope area P1, the slope area from the weak layer R2 to the weak layer R1 is numbered as slope area P2, and so on. n Weak layer to R n-1 The slope area between the weak layers is numbered as slope area P. n .

4. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 1, characterized in that: The mining parameters include: step height, flat plate width and step slope angle.

5. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 1, characterized in that: On the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed on each slope area according to the step form of the vertical mining working side, end side, and inner dump slope and mining parameters, and the mining parameters and slope cross-sectional shapes of each scheme during top-down vertical mining are obtained, including: Under the premise of satisfying the slope safety reserve coefficient, various slope shape designs are performed on each slope area using a longitudinal mining procedure according to the step form of the longitudinal mining working side, end side, and inner dump slope and mining parameters, thereby obtaining various slope cross-sectional shape schemes; The number of stages is determined based on the number of weak layers in the slope body; According to the number of stages, for each slope cross-sectional morphology scheme, the Morgenstern method is used to obtain the slope stability coefficient of each area, and the width of each flat plate is adjusted until the slope stability coefficient of each area meets the constraint conditions. The adjustment of the width of each flat plate is stopped, and the mining parameters and slope cross-sectional morphology of each scheme during top-down longitudinal mining are obtained.

6. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 5, characterized in that: The constraint conditions are calculated as follows: |Fs n -K n |<M Among them, Fs n is the slope stability coefficient at stage n, M is the preset threshold, K n is the safety reserve factor of the nth stage.

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

8. The method for collaborative optimization of slope morphology and mining procedures in a composite coal seam soft rock open-pit mine according to claim 1, characterized in that: The mining stages are refined according to the current status of the stope and the parameters of the end slope shape at each stage. Based on the internal tracking distance of the horizontal mining of the coal seam, a plan of the project 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 plan to guide subsequent open-pit coal mining, including: Refine the mining stages according to the current situation of the stope and the parameters of the end and side slopes at each stage; Based on the internal row tracking distance of horizontal mining of coal seams, mining project location, horizontal mining working side, vertical mining working side, end side, step form of internal dumping area and mining parameters, draw the plan of project location at each stage; A Gantt chart of slope mining progress is drawn based on the coal quantity at each stage and the mining sequence of each plan to guide subsequent open-pit coal mining.

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