Open pit with multi-area high drop filling and filling method

Abstract

The present invention discloses an open pit with multi-region high-drop filling and a filling method. The open pit filling method includes S1: dividing the open pit into multiple regions and determining the target filling height of each region, S2: selecting adjacent first and second regions from multiple regions, the first target filling height of the first region being lower than the second target filling height of the second region; S3: filling the first region to the first target filling height; S4: filling the second region to the first target filling height; S5: building a first-level retaining dam between the first region and the second region, and filling the second region from the first target filling height to the first filling height; S6: building a second-level retaining dam on the side of the first-level retaining dam away from the first region, and filling the second region from the first filling height to the second filling height; repeating S5 and S6 until the second region is filled to the second target filling height. The open pit filled according to the present invention has low construction difficulty and high firmness and safety.

Description

Technical Field

[0001] The present invention relates to the technical field of open pit filling, and in particular to an open pit with multi-region high-drop filling and a filling method. Background Art

[0002] Mineral resource mining leaves behind a large number of untreated open pits, seriously impacting the production and living environment of surrounding residents. Related technologies typically backfill open pits with dry piles of waste rock and tailings. This backfill method fails to completely seal the water channel between the open pit and the underground stope, impacting the underground mining system. Furthermore, this backfilled open pit is prone to forming a water basin effect, impacting surrounding safety and the environment. Therefore, there is a need for improvement. Summary of the Invention

[0003] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0004] In order to solve the problems existing in the backfilling of open pits in the related art, the applicant of the present invention proposed an open pit filling method in the prior patent application CN106168133A. The open pit filling method uses filling slurry to fill the open pit in layers in sequence, and finally fills the open pit as a whole to a substantially same filling height, that is, the final filling height difference between different areas of the open pit is not large, for example, generally less than a few meters.

[0005] Although the above-mentioned layered filling method solves the problem of water channels between the open pit and the underground stope to a certain extent, the inventors have found through research on examples of open pits filled using the above-mentioned filling method that the following problems still exist:

[0006] First, for large open pits, if they are filled as a whole, a large amount of filling slurry, sand and gravel and other materials will be consumed. In addition, it is difficult to transport the filling materials to the open pit, and the construction is difficult, resulting in very high costs.

[0007] Second, some open pits are restricted by the terrain. For example, most open pits are located in mountainous areas with large terrain differences, making it impossible to fill the open pits as a whole.

[0008] Third, due to the constraints of technology, environmental protection requirements or other factors, for some open-pits, if they are filled in as a whole, it will have an impact on the surrounding environment. For example, there are cultural relics around the open-pits, and laws and policies do not allow the open-pits to be filled in as a whole.

[0009] There is no filling method suitable for the above situation proposed in the relevant technology. Using the filling method in the relevant technology is not only difficult to construct, but also has high maintenance costs, large investments, and poor safety. In some cases, it is impossible to completely fill the open pit.

[0010] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0011] To this end, an embodiment of the present invention proposes a method for filling multi-area high-drop filling in an open pit, which has the advantages of low construction difficulty, low consumption of filling slurry, firm filling and safety.

[0012] An embodiment of the present invention also provides a multi-area high-drop open pit filled using the above-mentioned filling method. After filling, the open pit has a high drop of more than ten meters to hundreds of meters, and the filled open pit is firm and safe.

[0013] According to an embodiment of the present invention, a method for filling multiple areas of an open pit with a high drop includes: step S1: dividing the open pit into multiple areas and determining the target filling height of each area; step S2: selecting an adjacent first area and a second area from the multiple areas, the first target filling height of the first area being lower than the second target filling height of the second area; step S3: filling the first area to the first target filling height; step S4: filling the second area to the first target filling height; step S5: building a first-level retaining dam between the first area and the second area, and filling the second area from the first target filling height to the first filling height; step S6: building a second-level retaining dam on the side of the first-level retaining dam away from the first area, and filling the second area from the first filling height to the second filling height; repeating steps S5 and S6 until the second area is filled to the second target filling height; repeating steps S2-S6 to complete the filling of the multiple areas to their respective target filling heights.

[0014] According to the multi-area high-drop filling method for an open pit according to an embodiment of the present invention, the open pit is divided into multiple areas, and adjacent areas are filled with high drops. For example, the filling height difference of adjacent areas can be more than ten meters or even hundreds of meters. Specifically, the first area and the second area can be filled to the first target filling height first, and then the retaining dam can be built layer by layer between the first area and the second area, that is, the retaining dam is built in stages from bottom to top. Compared with the traditional method of only building a first-level retaining dam, the difficulty during construction is reduced, the investment is small, and the maintenance cost is low. Then the second area is filled layer by layer from the first target filling height to the second target filling height. In other words, each time a first-level retaining dam is built, the second area is filled on the side adjacent to the retaining dam and the second area; after the filling is completed, another first-level retaining dam is built, and then the second area is filled, until the second area is filled layer by layer from the first target filling height to the second target filling height. The open pit multi-area high-drop filling method of the above embodiment can reduce the construction difficulty when filling the open pit, consume less filling slurry, and the open pit after filling has high firmness and safety.

[0015] In some embodiments, each stage of the retaining dam has a slope extending toward the first area.

[0016] In some embodiments, when filling the second area, the filling is performed from a side adjacent to each stage of the dam toward a direction away from each stage of the dam.

[0017] In some embodiments, a soft permeable pipe is provided at the bottom of at least a portion of the retaining dam, and the soft permeable pipe extends into the filling material in the second area.

[0018] In some embodiments, a filter layer is provided on the upstream surface of each stage of the retaining dam, and the filter layer extends into the filling body in the second area.

[0019] In some embodiments, it further includes opening an intercepting ditch at the edge of the filling body in the second area, and opening a drainage ditch at the foot of at least a portion of the retaining dam, wherein the drainage ditch is connected to the intercepting ditch.

[0020] In some embodiments, a water reservoir is provided in the first area, and the intercepting ditch and the drainage ditch are connected to the water reservoir.

[0021] In some embodiments, the slope surface of the second area is covered with soil and greened.

[0022] According to an open pit with multi-area high-drop filling according to an embodiment of the present invention, the open pit includes multiple areas, and the multiple areas include adjacent first and second areas. The filling body height of the first area is lower than the filling body height of the second area. Between the first area and the second area, there are multi-level retaining dams stacked in sequence during the filling of the second area.

[0023] In some embodiments, each stage of the retaining dam has a slope extending toward the first area.

[0024] In some embodiments, a soft permeable pipe is provided at the bottom of at least a portion of the retaining dam, and the soft permeable pipe extends into the filling material in the second area.

[0025] In some embodiments, a filter layer is provided on the upstream surface of each stage of the retaining dam, and the filter layer extends into the filling body in the second area.

[0026] In some embodiments, the open pit with multi-area high-drop filling further includes a drainage ditch at the edge of the filling body in the second area, and a drainage ditch at the foot of at least a portion of the retaining dam, wherein the drainage ditch is connected to the drainage ditch.

[0027] In some embodiments, a water reservoir is provided in the first area, and the intercepting ditch and the drainage ditch are connected to the water reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic plan view of an open pit filled using the open pit multi-zone high-drop filling method according to an embodiment of the present invention.

[0029] Figure 2 along Figure 1 Cross-sectional view of AA in the figure.

[0030] Figure 3 yes Figure 2 Magnified view of B.

[0031] Figure 4 It is a schematic diagram of the filling process of an open pit multi-area high-drop filling method according to an embodiment of the present invention.

[0032] Reference numerals:

[0033] 1. First area; 2. Second area; 3. Retaining dam; 4. Slope; 5. Intercepting ditch; 6. Drainage ditch; 7. Reservoir. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] Reference below Figures 1 to 4 A method for filling an open pit with multiple zones and a high-drop filling method therein according to an embodiment of the present invention is described.

[0036] like Figures 1 to 4 As shown, the open pit multi-area high drop filling method according to an embodiment of the present invention includes:

[0037] Step S1: Divide the open pit into multiple areas and determine the target filling height of each area;

[0038] Step S2: selecting a first region 1 and a second region 2 adjacent to each other from the plurality of regions, wherein a first target filling height of the first region 1 is lower than a second target filling height of the second region 2;

[0039] Step S3: filling the first area 1 to a first target filling height;

[0040] Step S4: filling the second area 2 to a first target filling height;

[0041] Step S5: building a primary retaining dam between the first area 1 and the second area 2, and filling the second area 2 from the first target filling height to the first filling height;

[0042] Step S6: Building a secondary retaining dam on the side of the primary retaining dam away from the first area 1, and filling the second area 2 from the first filling height to the second filling height;

[0043] Repeat steps S5 and S6 until the second area 2 is filled to a second target filling height;

[0044] Repeat steps S2-S6 to complete filling of the multiple areas to their respective target filling heights.

[0045] According to the multi-area high-drop filling method for an open pit according to an embodiment of the present invention, the open pit is divided into multiple areas, and adjacent areas are filled with high drops. For example, the filling height difference of adjacent areas can be more than ten meters or even hundreds of meters. Specifically, the first area 1 and the second area 2 can be filled to the first target filling height first, and then the retaining dam 3 can be built layer by layer between the first area 1 and the second area 2, that is, the retaining dam 3 is built from bottom to top. Compared with the traditional method of only building a first-level retaining dam, the difficulty during construction is reduced, the investment is small, and the maintenance cost is low. Then the second area 2 is filled layer by layer from the first target filling height to the second target filling height. In other words, each time a first-level retaining dam is built, the second area 2 is filled on the side adjacent to the retaining dam 3 and the second area 2; after the filling is completed, another first-level retaining dam is built, and then the second area 2 is filled, until the second area 2 is filled layer by layer from the first target filling height to the second target filling height. The open pit multi-area high-drop filling method of the above embodiment can reduce the construction difficulty when filling the open pit, consume less filling slurry, and the open pit after filling has high firmness and safety.

[0046] In some embodiments, as Figure 2 and Figure 3 As shown, each level of the retaining dam has a slope 4 extending toward the first area 1. It can be understood that the side of each level of the retaining dam adjacent to the first area 1 has a slope 4 facing the first area 1 and sloping downward. After the multi-level retaining dam 3 is completed, the structure is a structure that gradually extends upward and tilts toward the second area 2. The multi-level retaining dam 3 has a certain inclination angle with the second area 2 to improve the strength of the multi-level retaining dam 3, thereby improving the firmness of the open pit after filling.

[0047] In some embodiments, as Figure 2 and Figure 3 As shown in FIG, when filling the second area 2, the filling is carried out from the side adjacent to each level of the retaining dam to the direction away from each level of the retaining dam. It can be understood that the filling direction of the second area 2 is from the side close to the retaining dam 3 ( Figure 2 the right side of the second area 2) to the side away from the retaining dam 3 ( Figure 2Preferably, the filling body adjacent to the retaining dam 3 is higher than the filling body away from the retaining dam 3, that is, the filling body is toward the side away from the retaining dam 3 ( Figure 2 The left side of the second region 2 in the retaining dam 3 is arranged downwardly and tilted. Since the area near the retaining dam 3 is filled first, the filling slurry solidifies first on the side of the second region 2 near the retaining dam 3, which is equivalent to providing auxiliary reinforcement for the retaining dam 3. This prevents unsolidified filling slurry from flowing out of the retaining dam 3 and improves the safety of the retaining dam 3 construction. Optionally, a geogrid can be installed at the bottom of the retaining dam 3 to enhance its strength and stability.

[0048] In some embodiments, a soft permeable pipe (not shown) is provided at the bottom of at least a portion of the retaining dams 3, extending into the backfill within the second region 2. For example, when the backfill slurry has poor consolidation, a soft permeable pipe may be provided at the bottom of every two retaining dams 3. Preferably, multiple soft permeable pipes are provided, evenly spaced along the length of the retaining dams 3. This allows liquid in the newly laid backfill to seep into the soft permeable pipes and be discharged from the end of the soft permeable pipe adjacent to the retaining dam 3, thereby improving the drainage and consolidation properties of the backfill.

[0049] In some embodiments, a filter layer (not shown) is provided on the upstream surface of each retaining dam, extending into the backfill within the second region 2. Specifically, a geotextile fabric can be provided on the upstream surface of the retaining dam 3, i.e., the upper surface of the backfill within the second region 2, as a filter layer. This layer extends along the side of the backfill away from the retaining dam 3 to the middle of the backfill. This prevents unset backfill slurry from leaking out of the retaining dam 3 while also maintaining the drainage of moisture within the backfill, thereby improving the robustness of the open pit backfill.

[0050] In some embodiments, intercepting ditches 5 are provided at the edges of the backfill within the second region 2, and drainage ditches 6 are provided at the toes of at least a portion of the retaining dams 3, with the drainage ditches 6 communicating with the intercepting ditches 5. Specifically, intercepting ditches 5 are provided at the edges of the backfill within the second region 2 near the outer peripheral wall of the second region 2, and drainage ditches 6 are provided at the toes of every two retaining dams 3. The drainage ditches 6 extend along the length of the retaining dams 3, and both ends of the drainage ditches 6 communicate with the intercepting ditches 5. Preferably, the intercepting ditches 5 are constructed of reinforced concrete, and the drainage ditches 6 are constructed of mortar-laid stone. During the rainy season, rainwater within the second region 2 is diverted through the drainage ditches 6 into the intercepting ditches 5 at its edges and then drained out of the second region 2, reducing erosion of the edges of the backfill within the second region 2. Furthermore, a reservoir 7 is provided within the first region 1, and the intercepting ditches 5 and drainage ditches 6 are connected to the reservoir 7. Thus, water within the intercepting ditches 5 and drainage ditches 6 can be drained into the reservoir 7, where rainwater is collected.

[0051] In some embodiments, the slope surface of the second area 2 is covered with soil and greened. Optionally, the slope surfaces of both the first area 1 and the second area 2 are covered with soil and greened, which can reduce soil and water loss on the surrounding walls of the first area 1 and the second area 2 when rainwater washes the surrounding walls of the first area 1 and the second area 2.

[0052] It should be noted that during the high-drop filling process in multiple zones of an open pit, it is necessary to test the physical and mechanical properties of the filling. Based on the test results, the stability of the edges of the filling in the first and second zones 1 and 2 is verified. The strength of the filling is also determined based on the physical and mechanical property test results, which serves as a basis for adjusting the slopes of the edges of the filling in the first and second zones 1 and 2. This improves the safety and firmness of the edges of the filling in the first and second zones 1 and 2.

[0053] Reference below Figures 1 to 4 The following describes a method for filling an open pit with multiple zones and high drop heights according to some specific examples of the present invention.

[0054] Step S1: Divide the open pit into multiple areas and determine the target filling height of each area.

[0055] Step S2: selecting a first area 1 and a second area 2 adjacent to each other from the plurality of areas, wherein a first target filling height of the first area 1 is lower than a second target filling height of the second area 2, wherein the target filling height of the first area 1 is -9 meters, and the target filling height of the second area 2 is -45 meters;

[0056] Step S3: filling the first area 1 to a first target filling height, i.e., to -45 meters;

[0057] Step S4: filling the second area 2 to the first target filling height, i.e., to -45 meters;

[0058] Step S5: constructing a primary retaining dam between the first area 1 and the second area 2, and filling the second area 2 from the first target filling height to the first filling height, wherein the first filling height is not higher than the height of the retaining dam 3; in addition, the retaining dam 3 can be constructed by filling the tailings with a mold bag method to form the retaining dam 3; or the retaining dam 3 can be formed by rolling and stacking waste rock;

[0059] Step S6: Building a secondary retaining dam on the side of the primary retaining dam away from the first area 1, and filling the second area 2 from the first filling height to the second filling height, wherein the second filling height is not higher than the height of the retaining dam 3;

[0060] Repeat steps S5 and S6 until the second area 2 is filled to the second target filling height, i.e., -9 meters. In other words, each time a retaining dam is built, the second area 2 is filled on the side of the retaining dam 3 adjacent to the second area 2. After filling to the predetermined height, the next retaining dam is built, and then the second area 2 is filled again. Ultimately, the filling height of the second area 2 is gradually filled from -45 meters to -9 meters.

[0061] Repeat steps S2-S6 to complete filling of the multiple areas to their respective target filling heights.

[0062] like Figure 2 and Figure 3 As shown, the side of each level of the retaining dam adjacent to the first area 1 has a slope 4 that is inclined downward toward the first area 1. After the multi-level retaining dam 3 is built, the structure is gradually extended upward and inclined toward the second area 2, so that the multi-level retaining dam 3 has a certain inclination angle with the second area 2 to improve the strength of the multi-level retaining dam 3.

[0063] When filling the second area 2, the filling slurry is filled from the right side of the second area 2 to the left side of the second area 2. The filling material near the retaining dam 3 is higher than the filling material farther away from the retaining dam 3, that is, the filling material is arranged downwardly and tilted toward the left side of the second area 2. Because the area near the retaining dam 3 is filled first, the filling material solidifies first on the side of the second area 2 near the retaining dam 3, which is equivalent to auxiliary reinforcement of the retaining dam 3. This prevents unsolidified filling slurry from flowing out of the retaining dam 3 and improves the safety of the retaining dam 3 construction.

[0064] When the consolidation of the filling body is poor, a plurality of soft permeable pipes are provided at the bottom of the retaining dam 3 every two levels. The plurality of soft permeable pipes are arranged at equal intervals along the length direction of the retaining dam 3, so that the liquid in the newly laid filling body can penetrate into the soft permeable pipes and be discharged from the end of the soft permeable pipes adjacent to the retaining dam 3, so as to improve the drainage and consolidation performance of the filling body. Furthermore, a geotextile is provided as a filter layer on the upstream surface of each level of the retaining dam, and extends along the side of the filling body away from the retaining dam 3, that is, to the left side of the filling body to the middle of the filling body. This can prevent the uncoagulated filling slurry from leaking out of the retaining dam 3, and at the same time will not affect the discharge of water in the filling body, so as to improve the firmness of the open pit filling.

[0065] like Figure 1 and Figure 3As shown, an intercepting ditch 5 is provided at the edge of the outer wall of the second area 2 near the filling body in the second area 2, and a drainage ditch 6 is provided at the foot of every two retaining dams 3. The drainage ditch 6 extends along the length of the retaining dam 3, and both ends of the drainage ditch 6 are connected to the intercepting ditch 5. The intercepting ditch 5 adopts a reinforced concrete structure, and the drainage ditch 6 adopts a mortar-laid stone structure. When the rainy season comes, the rainwater in the second area 2 will be diverted to the intercepting ditch 5 at its edge through the drainage ditch 6, and then discharged to the outside of the second area 2, reducing the erosion of the edge of the filling body in the second area 2 by rainwater. A water reservoir 7 is provided in the first area 1, and the intercepting ditch 5 and the drainage ditch 6 are connected to the water reservoir 7. Therefore, the water in the intercepting ditch 5 and the drainage ditch 6 can be discharged into the water reservoir 7 to collect the rainwater, and the water in the water reservoir 7 can be subsequently drawn out by a water pump. Furthermore, the slope surfaces of the first area 1 and the second area 2 are both covered with soil and greened, so that when rainwater washes the surrounding walls of the first area 1 and the second area 2, soil and water loss of the surrounding walls of the first area 1 and the second area 2 can be reduced.

[0066] The open pit with multi-region high-drop filling according to the embodiment of the present invention can be formed by using the open pit multi-region high-drop filling method according to any of the above embodiments of the present invention.

[0067] The open pit multi-area high-drop filling method and the open pit multi-area high-drop filling method according to the embodiment of the present invention have the advantages of low construction difficulty, low filling material consumption, firm filling and safety.

[0068] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0070] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0071] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0072] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for filling multi-area high-drop open pits, characterized in that: include: Step S1: Divide the open pit into multiple areas and determine the target filling height of each area; Step S2: selecting a first region and a second region adjacent to each other from the plurality of regions, wherein a first target filling height of the first region is lower than a second target filling height of the second region; Step S3: filling the first area to the first target filling height; Step S4: filling the second area to the first target filling height; Step S5: building a primary retaining dam between the first area and the second area, and filling the second area from the first target filling height to the first filling height; Step S6: building a secondary retaining dam on a side of the primary retaining dam away from the first area, and filling the second area from the first filling height to a second filling height; Repeat steps S5 and S6 until the second area is filled to the second target filling height; Repeat steps S2-S6 to complete filling of the plurality of areas to their respective target filling heights; The method further comprises providing an intercepting ditch at the edge of the filling body in the second area, and providing a drainage ditch at the foot of at least a portion of the retaining dam, wherein the drainage ditch is connected to the intercepting ditch; a water reservoir is provided in the first area, and the intercepting ditch and the drainage ditch are connected to the water reservoir; When filling the second area, the filling is carried out from the side adjacent to each level of the retaining dam toward the direction away from each level of the retaining dam; In the second region, the filling body adjacent to the retaining dam is higher than the filling body away from the retaining dam.

2. The open pit multi-area high drop filling method according to claim 1 is characterized in that: Each level of retaining dam has a slope extending toward the first area.

3. The open pit multi-area high drop filling method according to claim 1 is characterized in that: A soft water-permeable pipe is provided at the bottom of at least a portion of the retaining dam, and the soft water-permeable pipe extends into the filling body in the second area.

4. The open pit multi-area high drop filling method according to claim 1, characterized in that: An inverted filter layer is provided on the upstream surface of each level of retaining dam, and the inverted filter layer extends into the filling body in the second area.

5. The open pit multi-area high drop filling method according to claim 1 is characterized in that: The slope surface of the second area is covered with soil and greened.

6. An open pit with multi-area high-drop filling, characterized in that: The open pit is filled using the multi-zone high-drop filling method for an open pit according to any one of claims 1 to 5, wherein the open pit includes multiple zones, and the multiple zones include adjacent first and second zones, the height of the filling body in the first zone is lower than the height of the filling body in the second zone, and a multi-level retaining dam is provided between the first and second zones during the filling of the second zone; within the second zone, the filling body adjacent to the retaining dam is higher than the filling body away from the retaining dam.

7. The open pit with multi-zone high-drop filling according to claim 6, characterized in that: Each level of retaining dam has a slope extending toward the first area.

8. The open pit with multi-zone high-drop filling according to claim 6, characterized in that: A soft water-permeable pipe is provided at the bottom of at least a portion of the retaining dam, and the soft water-permeable pipe extends into the filling body in the second area.

9. The open pit with multi-zone high-drop filling according to claim 6, characterized in that: An inverted filter layer is provided on the upstream surface of each level of retaining dam, and the inverted filter layer extends into the filling body in the second area.

10. The open pit with multi-zone high-drop filling according to claim 6, characterized in that: It also includes opening an intercepting ditch at the edge of the filling body in the second area, and opening a drainage ditch at the foot of at least a part of the retaining dam, and the drainage ditch is connected to the intercepting ditch.

11. The open pit with multi-zone high-drop filling according to claim 10, characterized in that: A water reservoir is provided in the first area, and the intercepting ditch and the drainage ditch are connected to the water reservoir.

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