A steep slope mining method with strong discharge in an open pit

Abstract

The present application relates to the technical field of open coal mining, and discloses a kind of open-pit mine strong discharge steep slope mining method, comprising: according to open coal mining design, obtain the step form and mining parameters of each coal seam horizontal mining working slope, end slope and internal dump site slope in composite coal seam;Determine the mining technology and the operation equipment used for mining;The slope stability coefficient F of the lowermost coal seam to the surface in various distance combination schemes is calculated using numerical simulation software s , determine the safe distance of each coal seam horizontal mining working slope and internal dump site;Determine the initial section ditch position of each coal seam horizontal mining working slope, excavate section ditch channel, establish mining working face to carry out mining operation;Using zoning disposal method, the generated disposal materials of each coal seam horizontal mining working slope are disposed.The present application provides a determination scheme for mining parameters, technology and equipment, and determines the safe distance of multi-coal seam horizontal mining working slope and internal dump site, thereby guiding open-pit mine strong discharge steep slope mining operation, improving mining efficiency and quality.

Description

Technical Field

[0001] This invention relates to the field of open-pit coal mining technology, and in particular to a method for strong drainage and steep slope mining in open-pit mines. Background Technology

[0002] The benefits of implementing strong drainage and steep slope technology in open-pit mines are: firstly, it fully utilizes internal drainage space, shortens transportation distances, reduces external drainage costs, effectively lowers production costs, and improves the economic efficiency of open-pit mines; secondly, it shortens the exposure time and space of high, steep, and long slopes, which is beneficial to slope stability; and thirdly, it improves the coal resource recovery rate of open-pit coal mines and extends the service life of the mining area. Traditional mining methods involve returning the mining equipment to the starting position of the horizontal mining line in the deep coal seam after the deep coal seam mining is completed and the internal drainage area has reached a certain scale on the upper coal seam floor. This results in delayed internal drainage and more complex production management.

[0003] Patent CN112855162A discloses a method for mining the upper coal seam of the end face in a composite coal seam open-pit mine. This method utilizes the inner spoil heap's benches to create a working space, arranges mining equipment, and uses the inner spoil heap's benches as working platforms to perform segmented recovery of resources overlying the upper coal seam. This method extracts the upper coal seam and the interbedded rock between the coal seam and the mining level, and specifies that the length of the recovered end face coal in the advancing direction is equal to the width of the spoil heap's benches. Patent CN113742949B discloses a method for determining the mining width of a high-level coal seam in a composite coal seam open-pit mine. This method calculates the width of the mining width by adjusting the widths of the various benches between the coal seams. The difference in the width of the coal seam before and after adjustment is used to find the relationship between the width of the coal seam and the mining width. The high-level coal seam is extracted by utilizing the internal drainage support effect of horizontal mining. Patent CN111364999A discloses an integrated replacement method for end-side coal mining and filling in open-pit coal mines. This method divides the end-side coal in open-pit mines into several mining stages of equal length, and divides each stage into front and back sections. The replacement of the end-side coal is completed by alternating the front and back sections, realizing continuous mining and filling of end-side coal, which can maximize the extraction of end-side resources. However, it has problems such as large amount of tunneling work, long time cycle, high cost, and difficult construction. These patents all focus on the mining method of open-pit mines and the mining width of the upper coal seam. They do not consider the spatiotemporal evolution of the mining process during the advancement of the internal dump and the upper multi-coal seam horizontal mining working side, nor do they determine the safe distance between the upper multi-coal seam horizontal mining working side and the internal dump. Therefore, there is an urgent need to find a strong drainage and steep slope mining method for open-pit mines to provide technical support for subsequent open-pit mining. Summary of the Invention

[0004] The purpose of this invention is to provide a method for strong drainage and steep slope mining in open-pit mines, which fully considers the mining parameters, processes and equipment during the forward advance of the internal spoil heap and the multi-coal-seam cross-mining working face, and determines the safe distance between the multi-coal-seam cross-mining working face and the internal spoil heap, thereby guiding the strong drainage and steep slope mining operation in open-pit mines and improving mining efficiency and quality.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for open-pit mining with strong drainage and steep slopes, the method comprising the following steps:

[0007] S1, based on the open-pit coal mine mining design, obtain the bench form and mining parameters of the side slopes of the cross mining working face, end face and internal spoil disposal site of each coal seam in the composite coal seam;

[0008] S2, the mining process is determined based on the length of the working line and the haul distance between the horizontal mining working side and the inner spoil disposal site;

[0009] S3, Based on the mining parameters and mining process, determine the operating equipment to be used for mining;

[0010] S4. Based on the distance between the working face of each coal seam and the internal spoil heap, various distance combination schemes are designed. Numerical simulation software is used to calculate the slope stability coefficient F of the lowermost coal seam to the surface in each distance combination scheme. s The optimal design scheme for the safe distance between the cross-mining working face and the internal spoil heap of each coal seam is selected based on the distance combination scheme that meets the set conditions.

[0011] S5, determine the initial location and dimensions of the trenches for each coal seam's transverse mining working face, excavate the trenches according to the coal seam strike, and establish mining faces beside the trenches for mining operations.

[0012] S6. After the formation of the working face and internal spoil disposal site of each coal seam, the zoning spoil disposal method is adopted to determine the spoil disposal and transportation path of the spoil materials generated by the working face of each coal seam.

[0013] Furthermore, in step S2, the mining process is determined based on the length of the working line and the haulage distance between the transverse mining working face and the inner spoil heap, specifically including:

[0014] Taking into account the length of the working line and the haul distance between the horizontal mining working side and the internal spoil heap, a suitable open-pit mining technology was selected from the single-bucket excavator-truck mining technology, the wheel bucket excavator-belt conveyor technology, and the semi-continuous mining technology.

[0015] Further, in step S3, based on the mining parameters and mining process, the operating equipment used for mining is determined, specifically including:

[0016] Select appropriate operating equipment based on the mining technology, bench mining parameters, and in accordance with the "Code for Design of Open-Pit Coal Mines" (GB50197-2015).

[0017] Furthermore, in S4, the setting conditions specifically refer to:

[0018] |F s -K|≤0.005

[0019] Where K is the slope safety reserve coefficient.

[0020] Furthermore, in S4, the slope safety reserve coefficient K is determined based on the slope service life and the "Code for Design of Open-pit Coal Mines" (GB50197-2015) when mining the lowest coal seam.

[0021] Furthermore, in S5, the initial opening trench position of each coal seam's transverse mining working face is determined using the following method:

[0022] The composite coal seams are numbered from top to bottom, with the uppermost seam numbered M1, the second seam numbered M2, and so on, until the lowermost Nth seam is numbered M. N N is a positive integer ≥ 2;

[0023] When the top elevation of the internal spoil heap reaches the coal seam M N-i When determining the bottom elevation, determine the coal seam M. N-i The initial trench location for the horizontal mining operation is given by i, where i is a positive integer ≥ 1 and ≤ N-1.

[0024] Repeat the previous step. When the top elevation of the inner spoil heap reaches the bottom elevation of coal seam M1, determine the initial opening position of the trench in the cross-mining working face of coal seam M1.

[0025] Furthermore, in step S5, establishing a mining face beside the excavation trench for mining operations specifically includes:

[0026] Alongside the ditches, mining faces are established according to the mining parameters of each coal seam's horizontal mining working face. During the advancement of each coal seam's horizontal mining working face, mining strips are mined one by one. Each mining strip is mined, causing the working line to advance by one mining width.

[0027] Furthermore, S5 also includes: maintaining a set safe distance between the bottom line of the lowest step slope of each coal seam transverse mining working face and the bottom line of the top elevation step slope of the inner spoil heap.

[0028] Furthermore, in step S6, after the formation of the working face and internal spoil heap of each coal seam, a zoned spoil disposal method is adopted to determine the disposal and transportation path of the spoil materials generated by the working face of each coal seam, specifically including:

[0029] After the formation of the working face and internal spoil heap of each coal seam, coordinated development is carried out by setting a coordinated development step distance and maintaining the same advancement speed. The top elevation of the internal spoil heap is used as the zoning standard, and the spoil disposal operation is carried out by adopting a zoned disposal method.

[0030] According to specific embodiments provided by the present invention, the following technical effects are disclosed: The open-pit mine strong drainage steep slope mining method provided by the present invention firstly obtains the bench form and mining parameters of the cross-mining working side, end side, and internal spoil heap slope of each coal seam in the composite coal seam based on the open-pit coal mine mining design; and secondly, determines the mining process based on the working line length and the haul distance between the cross-mining working side and the internal spoil heap, and determines the mining equipment used in conjunction with the mining process; and thirdly, calculates the slope stability coefficient F of the lowest coal seam to the surface in various distance combination schemes using numerical simulation software. s The invention establishes safe distances between the cross-mining working face and the internal spoil heap for each coal seam. It also determines the initial location and dimensions of the trenches for each cross-mining working face, excavates these trenches, and establishes the mining face for operations. Furthermore, it employs a zoned spoil disposal method, determining the disposal and transportation routes for spoil generated from each cross-mining working face, thereby improving spoil disposal efficiency. Therefore, this invention provides clear guidance for open-pit mine operations involving strong spoil disposal on steep slopes, addressing mining parameters, mining processes, and operational equipment. It also leverages the slope stability coefficient F... s The safe distance between the working face of each coal seam and the internal spoil heap has been determined, which can effectively improve the coal resource recovery rate, optimize the production process and economic benefits while ensuring the safety and stability of the slope. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of the open-pit mine strong drainage steep slope mining method in an embodiment of the present invention;

[0033] Figure 2 This is a schematic cross-sectional view of a steep slope in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of open-pit coal mine horizontal mining and internal drainage in an embodiment of the present invention;

[0035] Figure 4 In this embodiment of the invention, the safe distance between the M2 cross-mining working side and the inner spoil heap is 50m, and the safe distance between the M1 cross-mining working side and the inner spoil heap is 40m. Schematic diagram of strong-drainage steep-slope mining.

[0036] Figure 5 In this embodiment of the invention, the safe distance between the M2 horizontal mining working side and the inner spoil heap is 90m, and the safe distance between the M1 horizontal mining working side and the inner spoil heap is 50m. Schematic diagram of strong drainage steep slope mining.

[0037] Figure 6 In this embodiment of the invention, the safe distance between the M2 cross-mining working side and the inner spoil heap is 50m, and the safe distance between the M1 cross-mining working side and the inner spoil heap is 40m. This is a schematic diagram of the numerical simulation results of strong spoil heap and steep slope mining.

[0038] Figure 7 In this embodiment of the invention, the safe distance between the M2 cross-mining working side and the inner spoil heap is 90m, and the safe distance between the M1 cross-mining working side and the inner spoil heap is 50m. This is a schematic diagram of the numerical simulation results of strong spoil heap and steep slope mining.

[0039] Figure 8 This is a schematic diagram illustrating the 50m safe distance maintained between the bottom line of the lowest step slope of the inner spoil heap and the bottom line of the lowest step slope of the M2 transverse mining working slope in this embodiment of the invention.

[0040] Figure 9 This is a schematic diagram of the initial trenching operation area of ​​the M1 horizontal mining working face in an embodiment of the present invention;

[0041] Figure 10 This is a partially enlarged schematic diagram of the initial trenching operation area of ​​the M1 horizontal mining working face in an embodiment of the present invention;

[0042] Figure 11 This is a schematic diagram illustrating the 40m safe distance maintained between the bottom line of the inner spoil heap +666 flat slope and the bottom line of the lowest step slope of the M1 transverse mining working slope in this embodiment of the invention.

[0043] Figure 12 This is a schematic diagram illustrating the coordinated development of the M2 horizontal mining working side, the M1 horizontal mining working side, and the internal spoil heap in an embodiment of the present invention.

[0044] Figure 13 This is a schematic diagram of the zoning and disposal of internal spoil heaps in an embodiment of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The purpose of this invention is to provide a method for strong drainage and steep slope mining in open-pit mines, which fully considers the mining parameters, processes, and equipment during the forward advance of the inner spoil heap and the multi-coal seam cross-mining working face, and determines the safe distance between the multi-coal seam cross-mining working face and the inner spoil heap, thereby guiding the strong drainage and steep slope mining operation in open-pit mines; overcoming the shortcomings of existing open-pit mining methods that do not consider the spatiotemporal evolution of the mining process during the forward advance of the inner spoil heap and the upper multi-coal seam cross-mining working face, and do not determine the safe distance between the upper multi-coal seam cross-mining working face and the inner spoil heap.

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 1 As shown, the open-pit mine strong drainage and steep slope mining method provided by the present invention includes the following steps:

[0049] S1. Based on the open-pit coal mine mining design, obtain the step form and mining parameters of the side slopes of the cross mining working face, end face and internal spoil disposal site of each coal seam in the composite coal seam;

[0050] S2. Determine the mining process based on the length of the working line and the haul distance between the horizontal mining working side and the internal spoil heap. Specifically, taking into account the length of the working line and the haul distance between the horizontal mining working side and the internal spoil heap, select a suitable open-pit mining process from the single-bucket excavator-truck mining process, the wheel bucket excavator-belt conveyor process, and the semi-continuous mining process.

[0051] S3, Based on the mining parameters and mining process, determine the operating equipment to be used for mining;

[0052] S4. Based on the distance between the working face of each coal seam and the internal spoil heap, various distance combination schemes are designed. Numerical simulation software is used to calculate the slope stability coefficient F of the lowermost coal seam to the surface in each distance combination scheme. s Select the one that matches |F s The distance combination scheme under the condition -K|≤0.005 is the optimal design scheme for the safe distance between the working side of each coal seam and the inner spoil heap; where K is the slope safety reserve coefficient, which is determined according to the slope service life and the "Code for Design of Open-pit Coal Mines" (GB50197-2015) when mining the lowermost coal seam.

[0053] S5. Determine the initial location and dimensions of the trenches for each coal seam's transverse mining working face. Excavate the trenches according to the coal seam strike, and establish mining faces beside the trenches for mining operations. For composite coal seams, they can be numbered from top to bottom, with the uppermost coal seam numbered M1, the second coal seam numbered M2, ... up to the lowermost Nth coal seam numbered M... NN is a positive integer ≥ 2; when the top elevation of the internal spoil heap develops to the coal seam M N-i When determining the bottom elevation, determine the coal seam M. N-i The initial opening position of the trench in the cross-mining working face is determined, where i is a positive integer ≥1 and ≤N-1; repeat the previous step, and when the top elevation of the inner spoil heap develops to the bottom elevation of coal seam M1, determine the initial opening position of the trench in the cross-mining working face of coal seam M1.

[0054] S6. After the formation of the working face and internal spoil disposal site of each coal seam, the zoning spoil disposal method is adopted to determine the spoil disposal and transportation path of the spoil materials generated by the working face of each coal seam.

[0055] Example:

[0056] This invention uses the north slope of an open-pit coal mine in Inner Mongolia as a specific example to illustrate a method for strong drainage and steep slope mining in open-pit mines, specifically including the following steps:

[0057] Step 1: Number the composite coal seams from top to bottom, with the uppermost seam numbered M1, the second seam numbered M2, and so on, until the lowermost Nth seam is numbered M. N For the northern slope of an open-pit coal mine in Inner Mongolia, there are two coal seams, N=2. They are numbered from top to bottom, with the uppermost coal seam numbered M1 and the lowermost coal seam numbered M2.

[0058] Step 2: Based on the open-pit coal mine design, obtain the bench form and mining parameters of the cross-mining working side, end side, and internal spoil heap for each coal seam;

[0059] Table 1 shows the bench form and mining parameters of the north slope of an open-pit coal mine in Inner Mongolia, including the cross-mining working face and internal spoil heap for coal seams M1 and M2. The slope morphology from the stope to the boundary is as follows: Figure 2 As shown in the figure. By measuring the cross-sectional area of ​​M1 and M2 and the length of the end face during steep slope mining, the coal resource volume to be recovered can be calculated to be 770,000 tons.

[0060] Table 1. Parameters and types of slope steps.

[0061]

[0062] Step 3: Based on the service life of the slope and the "Code for Design of Open-pit Coal Mines" (GB50197-2015), determine the slope safety reserve coefficient K when mining the lowermost coal seam M2;

[0063] In this embodiment, the non-working slope service life is less than 10 years, and the slope safety reserve coefficient K is selected as 1.2.

[0064] Step 4: Select the appropriate mining technology based on the length of the working line and the haul distance between the working wall and the inner spoil heap;

[0065] In this embodiment, the working line is arranged laterally, that is, perpendicular to the orientation of the open-pit mine. Figure 3 As shown, the working line is relatively short, so the mobile and flexible single-bucket excavator-truck mining process should be selected.

[0066] Step 5: Select appropriate operating equipment based on the mining technology, bench mining parameters, and in accordance with the "Code for Design of Open-Pit Coal Mines" (GB50197-2015);

[0067] In this embodiment, the bench heights of both the M2 and M1 cross-mining working sides are 12m. According to the regulations on bench height for intermittent mining processes in the "Code for Design of Open-Pit Coal Mines" (GB50197-2015), a bucket capacity of 4m³ should be selected. 3 Based on the previous matching relationship between excavators and trucks in open-pit coal mines in my country, a dump truck with a load capacity of 30t should be selected.

[0068] Step 6: Based on the distance between the working face of each coal seam and the internal spoil heap, design multiple distance combination schemes, and use numerical simulation software to calculate the stability coefficient F of the slope from the lowermost coal seam M2 to the surface in each scheme. s When the slope stability coefficient F s Conforms to |F s When -K|≤0.005, the optimal design scheme for the safe distance between the working face of each coal seam and the internal spoil heap can be obtained;

[0069] In this embodiment, two schemes were established. Scheme 1 sets the safety distance between the cross-mining working face of coal seam M1 and the internal spoil heap at 40m, and the safety distance between the cross-mining working face of coal seam M2 and the internal spoil heap at 50m. Figure 4 As shown; Option 2 sets the safety distance between the cross-mining working face of coal seam M1 and the internal spoil heap at 50m, and the safety distance between the cross-mining working face of coal seam M2 and the internal spoil heap at 90m. Figure 5 As shown. The slope stability of the two schemes was calculated separately, and the results are as follows. Figure 6 , Figure 7 As shown. The slope stability coefficient F of the proposed scheme is... s =1.204, |1.204-1.2|<0.005, which meets the slope stability requirements; Scheme 2 slope stability coefficient F s =1.184, |1.184-1.2|>0.005, which does not meet the slope stability requirements. Therefore, the final safe distance between the cross-mining working face of coal seam M1 and the internal spoil heap is determined to be 40m, and the safe distance between the cross-mining working face of coal seam M2 and the internal spoil heap is determined to be 50m. When the cross-mining working face of coal seam M2 advances a certain distance and the internal spoil heap can be constructed, the bottom line of the lowest step slope of the cross-mining working face of coal seam M2 and the bottom line of the lowest step slope of the internal spoil heap should maintain a safe distance of 50m. Figure 8 As shown.

[0070] Step 7: When the top elevation of the inner spoil heap reaches the bottom elevation of coal seam M1, determine the initial opening position of the trench in the M1 cross-mining working face;

[0071] In this embodiment, there are only two coal seams. When the top elevation of the inner spoil heap develops to the bottom elevation of coal seam M1 + 666, the initial opening position of the cross-mining working face of coal seam M1 is determined as follows: Figure 9 As shown, based on the operating parameters of the mining equipment, the length of the excavation trench is determined to be 35m, and the width of the excavation trench is 40m. Figure 10 As shown. A mining face is established beside the section trench according to the mining parameters of the M1 coal seam transverse mining face. During the advancement of the M1 coal seam transverse mining face, mining strips are mined one by one. For each mining strip, the working line is pushed forward by one mining width. The bottom line of the lowest bench slope of the M1 coal seam transverse mining face should maintain a safe distance of 40m from the bottom line of the bench slope at the +666 elevation of the inner spoil heap. Figure 11 As shown.

[0072] Step 8: After the formation of the working face and internal spoil disposal site of each coal seam, the disposal and transportation path of the waste materials generated by the horizontal mining working face of each coal seam is determined by adopting the zoned disposal method.

[0073] In this embodiment, after the formation of the cross-mining working face of coal seam M1, the cross-mining working face of coal seam M2, and the internal spoil heap, the three develop in synergy, meaning they advance at the same speed. Figure 12 As shown. A zoned dumping method is adopted. Waste material generated from the cross-mining of coal seam M2 is mainly dumped through the end face to the dumping platform below the +666 elevation in the inner dumping area. Waste material generated from the cross-mining of coal seam M1 is dumped through the end face to the dumping platform above the +666 elevation in the inner dumping area. When the inner dumping space below the +666 elevation is insufficient to accommodate the waste material generated from the cross-mining of coal seam M2, trucks can ascend through the end face to the inner dumping platform above the +666 elevation for dumping operations. Figure 13 As shown. If there are two or more coal seams in the composite slope, the zoning and disposal method should be that the disposal materials generated by the cross-mining working face of each coal seam are disposed of to the inner spoil disposal platform between the bottom elevation of the coal seam and the bottom elevation of the previous coal seam.

[0074] In summary, the open-pit mine strong drainage steep slope mining method provided by this invention offers clear guidance for open-pit mine strong drainage steep slope mining operations in terms of mining parameters, mining technology, and operating equipment, and is based on the slope stability coefficient F. sThe safe distance between the cross-mining working face of each coal seam and the internal spoil heap was determined, which can effectively improve the coal resource recovery rate, optimize the production process and economic benefits while ensuring the safety and stability of the slope. In addition, a zoned spoil disposal method was adopted to determine the disposal and transportation path of the spoil materials generated by the cross-mining working face of each coal seam, thereby improving the efficiency of spoil disposal operations.

[0075] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for open-pit mining with strong drainage and steep slopes, characterized in that, Includes the following steps: S1, based on the open-pit coal mine mining design, obtain the bench form and mining parameters of the side slopes of the cross mining working face, end face and internal spoil disposal site of each coal seam in the composite coal seam; S2, the mining process is determined based on the length of the working line and the haul distance between the horizontal mining working side and the inner spoil disposal site; S3, Based on the mining parameters and mining process, determine the operating equipment to be used for mining; S4. Based on the distance between the working face of each coal seam and the internal spoil heap, various distance combination schemes are designed. Numerical simulation software is used to calculate the slope stability coefficient of the lowermost coal seam to the surface in each distance combination scheme. F s The optimal design scheme for the safe distance between the cross-mining working face and the internal spoil heap of each coal seam is selected based on the set conditions; the set conditions specifically refer to: |F s -K|≤0.005 in, K This refers to the slope safety reserve coefficient. S5, determine the initial location and dimensions of the trenches for each coal seam's transverse mining sidewall, excavate the trenches according to the coal seam strike, and establish mining faces beside the trenches for mining operations; S5, determining the initial location of the trenches for each coal seam's transverse mining sidewall is specifically achieved using the following method: The composite coal seams are numbered from top to bottom, with the uppermost seam numbered M1, the second seam numbered M2, and so on, until the lowermost Nth seam is numbered M. N N is a positive integer ≥ 2; When the top elevation of the internal spoil heap reaches the coal seam M N-i When determining the bottom elevation, determine the coal seam M. N-i The initial trench location for the horizontal mining operation is given by i, where i is a positive integer ≥ 1 and ≤ N-1. Repeat the previous step. When the top elevation of the inner spoil heap reaches the bottom elevation of coal seam M1, determine the initial opening position of the cross-mining working face of coal seam M1. S6, after the formation of the working face and internal spoil heap of each coal seam, adopts a zoned spoil disposal method to determine the disposal and transportation path of the spoil generated by the working face of each coal seam, specifically including: After the formation of the working face and internal spoil heap of each coal seam, coordinated development is carried out by setting a coordinated development step distance and maintaining the same advancement speed. The top elevation of the internal spoil heap is used as the zoning standard, and the spoil disposal operation is carried out by adopting a zoned disposal method.

2. The open-pit mine strong drainage and steep slope mining method according to claim 1, characterized in that, In step S2, the mining process is determined based on the length of the working line and the haulage distance between the transverse mining working side and the inner spoil heap, specifically including: Taking into account the length of the working line and the haul distance between the horizontal mining working side and the internal spoil heap, a suitable open-pit mining technology was selected from the single-bucket excavator-truck mining technology, the wheel bucket excavator-belt conveyor technology, and the semi-continuous mining technology.

3. The open-pit mine strong drainage and steep slope mining method according to claim 1, characterized in that, S3, based on the mining parameters and mining process, determines the operating equipment used for mining, specifically including: Select appropriate operating equipment based on the mining technology, bench mining parameters, and in accordance with the "Code for Design of Open-Pit Coal Mines" (GB50197-2015).

4. The open-pit mine strong drainage and steep slope mining method according to claim 1, characterized in that, In S4, the slope safety reserve factor K Yes: Determine the slope safety reserve coefficient when mining the lowest coal seam based on the slope service life and the "Code for Design of Open-pit Coal Mines" (GB50197-2015).

5. The open-pit mine strong drainage and steep slope mining method according to claim 1, characterized in that, In step S5, establishing a mining face beside the trench for mining operations specifically includes: Alongside the ditches, mining faces are established according to the mining parameters of each coal seam's horizontal mining working face. During the advancement of each coal seam's horizontal mining working face, mining strips are mined one by one. Each mining strip is mined, causing the working line to advance by one mining width.

6. The open-pit mine strong drainage and steep slope mining method according to claim 1, characterized in that, S5 also includes: maintaining a set safe distance between the bottom line of the lowest step slope of each coal seam horizontal mining working face and the bottom line of the top elevation step slope of the inner spoil heap.

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