A method for constructing a water-retaining dump for an open-pit mine

Abstract

The present invention discloses a method for constructing a water-retaining dump for an open-pit mine. In the process of normal open-pit mine stripping to form a boundary open-pit mine dump, a water collection wall is constructed in layers on the slope of the first dumping step; after the first dumping step reaches the final construction height, a circular water collection trough is excavated on the dumping step platform; a centralized water collection well is excavated downward at both ends of the dumping step platform, and the wall collection pipe and the trough collection pipe in each layer of the water collection wall are respectively connected to the centralized water collection well nearby; at this point, the first dumping step is constructed; according to the above method, a second dumping step is constructed on the first dumping step; and so on, until the last dumping step is constructed. The present invention realizes that water can be retained when the water on the dumping step slope is small, water can be drained away when the water on the slope is large, water can be stored when the water on the slope is abundant, and water can be replenished in time when the water on the slope is exhausted, so as to avoid excessive water collection affecting the stability of the dumping site.

Description

Technical Field

[0001] The invention relates to a method for constructing a spoil dump, in particular to a method for constructing a water-retaining spoil dump for an open-pit mine. Background Art

[0002] The slope angle of the steps of the open-pit mine dump is mostly the natural repose angle of the material, and the angle generally exceeds 30°. When greening, the slope water collection effect is poor. During irrigation or rainfall, water flows quickly through the slope, and the soil seepage is small, which makes it difficult to meet the growth needs of slope plants. The traditional slope water collection methods such as laying fish scale pits and digging water collection ditches can achieve a certain water collection effect, but the scheme has the disadvantages of complex construction process, long cycle, and high cost. The damage to the slope by the scheme is also very likely to affect the stability of the slope of the dump. At the same time, when facing heavy rain and other situations, the scheme is prone to excessive water collection, which in turn weakens the stability of the dump. Combined with the needs of the site, the study believes that the water collection scheme of the dump slope should achieve the following effects: when the slope water is small, the water should be retained; when the slope water is large, the water should be drained away; when the slope water is abundant, the water should be stored; when the slope water is exhausted, the water should be replenished. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for constructing a water-retaining spoil dump in an open-pit mine. The constructed spoil dump can retain water when the water on the slope is small, drain water when the water on the slope is large, store water when the water on the slope is abundant, and replenish water when the water on the slope is exhausted. The slope stability of the spoil dump is high.

[0004] To achieve the above object, the present invention provides the following technical solutions: a method for constructing a water-retaining dump in an open-pit mine, comprising the steps of constructing a layered water collection wall, constructing an annular water collection trough and constructing a centralized water collection well;

[0005] Constructing layered water collection walls:

[0006] In the process of normal open-pit mine stripping to form the boundary open-pit mine dump, a water collection wall is constructed in layers on the slope of the first dumping step; when the height of the dumping step reaches the construction height of the first layer of water collection wall, a reverse slope step with a slope opposite to the dumping step is constructed at the edge of the step, and the reverse slope step is continuously arranged along the dumping step to both ends, and then 1-2 layers of infiltration pipes are arranged on the reverse slope step, and each layer has multiple infiltration pipes arranged side by side, and fine sand is filled between the infiltration pipes as a protective layer. At the end of the reverse slope step, a water collection wall is set next to the infiltration pipe. The collection pipes inside the wall, the infiltration pipes and the collection pipes inside the wall are continuously arranged along the soil discharge step until both ends are closed. The water absorption layer is laid on the outside of the protective layer and the collection pipes inside the wall until the height of the water collection wall of this layer is reached. At this time, the construction of the first layer of water collection wall is completed; then the open-pit mine stripping materials are discharged normally on the plane where the first layer of water collection wall is located. When the height of the soil discharge step is gradually increased to reach the construction height of the second layer of water collection wall, the second layer of water collection wall is constructed according to the method of constructing the first layer of water collection wall, and so on, until the top layer of water collection wall is constructed;

[0007] Constructing a circular sump:

[0008] After the first soil dumping step reaches the final construction height, a circular water collection trough is excavated on the soil dumping step platform at a distance of 3m from the surrounding boundaries. Permeable geotextiles are laid on the bottom and two sides of the circular water collection trough. Continuous in-trough collection pipes are laid on the permeable geotextiles on the bottom. The remaining space in the circular water collection trough is filled with materials as a water storage layer.

[0009] Constructing centralized water collection wells:

[0010] A centralized water collection well is excavated downwards at both ends of one side close to the outer boundary of the soil discharge step platform. The wall collection pipes and the trough collection pipes in each layer of water collection wall are connected to the centralized water collection wells nearby. At this point, the first soil discharge step is completed.

[0011] According to the above method, the second soil discharge step is constructed on the first soil discharge step; and so on, until the last soil discharge step is constructed.

[0012] Furthermore, in the step of constructing the layered water collection wall, the height of the lowest water collection wall is 2.5-3.5m, the top width is 4.5-5.5m, the height of the starting end of the reverse slope step in the lowest water collection wall is 0.5m, and the slope is 3%; the intervals between adjacent water collection walls are the same, both 3-5m.

[0013] Furthermore, the height of the upper water collection wall is 0.5 m lower than that of the lower water collection wall, and the height of the reverse slope step in the upper water collection wall is 0.1 m lower than that of the reverse slope step in the lower water collection wall; the lower limit height of the water collection wall is 1 m, and the lower limit height of the reverse slope step is 0.2 m.

[0014] Furthermore, in the step of constructing centralized water collection wells, one more centralized water collection well is dug for every 1 km the distance between the centralized water collection wells at both ends exceeds, and all the centralized water collection wells are spaced at equal distances.

[0015] Furthermore, valves are provided at the connection points between the collecting pipe in the wall, the collecting pipe in the trough and the centralized water collection well.

[0016] Furthermore, the cross-section of the water collection wall is trapezoidal and the slope is the natural repose angle of the material.

[0017] Furthermore, the collecting pipe inside the wall and the collecting pipe inside the trough are both perforated rubber tubes.

[0018] Compared with the prior art, the present invention can retain water when the water level on the slope of the drainage step is small, drain water when the water level on the slope is large, store water when the water level on the slope is abundant, and replenish water in time when the water level on the slope is exhausted; the combined design of the layered water collection wall and the infiltration pipe, collection pipe, and water absorption layer inside it realizes the layered, zoned, and staged water storage and replenishment of the slope, which can effectively store water and replenish water continuously. The reverse slope design of the reverse slope step can ensure that the water enters the infiltration pipe one by one along the slope and finally enters the collection pipe, thereby ensuring water storage efficiency. The annular water collection trough effectively collects platform water, which can improve the water collection effect, reduce the transition seepage of the step, and make up for the shortcoming of insufficient water storage of the thinner water collection wall at the top, and complement the water replenishment of the vegetation on the upper slope of the step. The collection pipe is controllably connected to the centralized water collection well, so that when the water level in the centralized water collection well is low, it can ensure that there is water in the collection pipe at a high place, which is convenient for implementing the water replenishment process. The raw materials used in the present invention are mostly strippings from open-pit mines, the construction process is simple, the impact on mine dumping operations is small, the capacity of the dumping site is not affected, and the construction cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the arrangement of the water collection wall of the present invention;

[0020] Figure 2 It is a schematic diagram of the longitudinal section structure of the water collection wall of the present invention;

[0021] Figure 3 It is a schematic diagram of the longitudinal cross-section structure of the annular water collecting tank of the present invention;

[0022] Figure 4 This is a schematic diagram of the arrangement position of the centralized water collection well of the present invention;

[0023] In the figure: 1-open pit mine dump; 2-slope of dumping step; 3-water collection wall; 4-reverse slope step; 5-permeability pipe; 6-protective layer; 7-collection pipe in the wall; 8-water absorption layer; 9-drainage step platform; 10-annular water collection trough; 11-permeable geotextile; 12-collection pipe in the trough; 13-water storage layer; 14-centralized water collection well. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the present invention provides a technical solution, the open-pit mine dump 1 is divided into multiple dumping steps, and the dumping steps are constructed from bottom to top. The construction of each dumping step includes three steps: constructing a layered water collection wall, constructing an annular water collection trough, and constructing a centralized water collection well.

[0027] Constructing layered water collection walls:

[0028] like Figure 1 As shown, in the process of normal open-pit mine stripping material discharge to form the boundary open-pit mine dump 1, a water collection wall 3 is constructed in layers on the slope 2 of the first dumping step. The cross section of the water collection wall 3 is trapezoidal and the slope is the natural repose angle of the material; when the height of the dumping step reaches the construction height of the first layer of the water collection wall 3, as shown in FIG. Figure 2 As shown, a reverse slope step 4 with a slope opposite to the slope 2 of the soil discharge step is constructed by a bulldozer at the edge of the step. The reverse slope step 4 is continuously arranged along the soil discharge step to both ends, and then 1-2 layers of infiltration pipes 5 are arranged on the reverse slope step 4. The infiltration pipes 5 are hollow cylindrical water-permeable pipes. The outer diameter of the infiltration pipes 5 is about 0.3m, and the inner diameter is about 0.2m. Multiple infiltration pipes 5 are arranged side by side in each layer. Fine sand is filled between the infiltration pipes 5 as a protective layer 6. The protective layer 6 can not only prevent the large pieces of material from squeezing and damaging the infiltration pipes 5, but also play a certain filtering and infiltration role; at the end of the reverse slope step 4, an in-wall collection pipe 7 is arranged next to the infiltration pipe 5, and the infiltration pipe 5 and the in-wall collection pipe 7 are continuously arranged along the soil discharge step. Until both ends are closed, the crushed stone materials or other block-shaped materials that do not disintegrate when exposed to water in the open-pit mine stripping materials are discarded outside the protective layer 6 and the collecting pipe 7 inside the wall, and the water-absorbing layer 8 is laid to build the height of the water-collecting wall 3, that is, the total height of the water-absorbing layer 8 and the reverse slope step 4 is the height of the water-collecting wall 3. The main function of the water-absorbing layer 8 is to absorb and store water by utilizing the pores between the materials. At this time, the first layer of water-collecting wall 3 is completed; the height of the first layer of water-collecting wall 3 is 2.5-3.5m, preferably 3m, and the top width is 4.5-5.5m, preferably 5m. The height of the starting end of the reverse slope step 4 in the first layer of water-collecting wall 3, that is, close to the slope of the soil discharge step, is 0.5m, and the slope is 3%.

[0029] After the first layer of water collection wall 3 is constructed, the open-pit mine stripping materials are normally discharged on the plane where the first layer of water collection wall 3 is located. When the height of the soil discharge step gradually increases to reach the construction height of the second layer of water collection wall 3, the second layer of water collection wall 3 is constructed according to the method of constructing the first layer of water collection wall 3. The height of the water collection wall 3 shows a decreasing trend from bottom to top. The height of the second layer of water collection wall 3 is 0.5 m lower than the height of the first layer of water collection wall 3, and the height of the reverse slope step 4 in the second layer of water collection wall 3 is 0.1 m lower than the height of the reverse slope step 4 in the first layer of water collection wall 3. After the second layer of water collection wall 3 is constructed, the third layer of water collection wall 3 is constructed according to the same method, and so on, until the top layer of water collection wall 3 is constructed. It should be noted that the lower limit height of the water collection wall 3 is 1m, and the lower limit height of the reverse slope step 4 is 0.2m. The distances between adjacent water-collecting walls 3 are the same, both 3-5m. When the soil water absorption of the open-pit mine spoil dump 1 is strong, 3m is selected as the distance between adjacent water-collecting walls 3, otherwise 5m is selected. The main purpose is to allow the water-collecting walls 3 to absorb more water so that it will not be absorbed by the spoil dump itself, affecting the stability of the spoil dump.

[0030] Constructing a circular sump:

[0031] like Figure 3 As shown, after the first soil discharge step reaches the final construction height, a circular continuous trench with a depth of about 1m and a width of about 2m is excavated at a position 3m away from the surrounding boundaries on the soil discharge step platform 9 as a circular water collection tank 10, and a permeable geotextile 11 is laid on the bottom and both sides of the circular water collection tank 10, and a continuous in-trough collecting pipe 12 is laid on the permeable geotextile 11 on the bottom. The direction of the in-trough collecting pipe 12 is consistent with that of the circular water collection tank 10 and is also in a ring shape. The remaining space in the circular water collection tank 10 is filled with open-pit mine stripping gravel or other blocky materials that do not disintegrate when exposed to water as a water storage layer 13;

[0032] Constructing centralized water collection wells:

[0033] like Figure 4 As shown, a centralized water collection well 14 is excavated downwards at each end of one side close to the outer boundary of the soil discharge step platform 9. According to the on-site conditions, the centralized water collection well 14 can be excavated within a range of about 7m from the outer boundary of the soil discharge step platform 9. Preferably, the centralized water collection well 14 is excavated at the position of the annular water collection trough 10; when the centralized water collection wells 14 at both ends are more than 1km apart, one more centralized water collection well 14 is excavated, and all the centralized water collection wells 14 are spaced at equal distances. The wall collection pipe 7 and the trough collection pipe 12 in each layer of the water collection wall 3 are connected to the centralized water collection well 14 nearby, and valves are provided at the connecting points.

[0034] At this point, the first dumping step is constructed; the second dumping step is constructed on the first dumping step according to the above method; and so on, until the last dumping step is constructed. The present invention is designed and constructed based on the formation process of the open-pit mine dumping yard, and is formed following the formation of the open-pit mine dumping yard.

[0035] When the soil dump constructed according to the present invention is artificially irrigated on the slope of the soil dumping step or it rains lightly, generally speaking, water flows slowly down along the slope from the top of the soil dumping step. When passing through each water collection wall 3, a large amount of water will penetrate into the water absorption layer 8 of the water collection wall 3. However, since the water absorption layer 8 is low in height and has limited water absorption capacity, during the saturation process of the upper water collection wall 3, excess water will continue to flow down along the slope and enter each lower water collection wall 3 layer by layer. As the height of the water collection wall 3 increases layer by layer, the water absorption capacity also increases layer by layer, and the water storage capacity also increases layer by layer.

[0036] In this process, because the water flows down from the top, the upper water collection wall 3 is in contact with the water for a long time, and the internal water will gradually enter the infiltration pipe 5 and be stored in the infiltration pipe; when watering or rainfall continues, the excess water will enter the collection pipe 7 inside the wall, and then enter the centralized water collection well 14 for storage, avoiding excessive water absorption inside the soil discharge step. The reverse slope step 4 can ensure that the water enters the infiltration pipe 5 one by one and finally enters the collection pipe 7 inside the wall, ensuring the water storage efficiency and avoiding the loss of water resources during the irrigation process. Because the height of the water collection wall 3 gradually increases, the water storage capacity gradually increases, and the water content is not large during artificial irrigation or light rain, in this case, most of the water on the slope 2 of the soil discharge step will be absorbed and will not flow to the soil discharge step platform 9.

[0037] When it rains heavily or continuously, a large amount of water directly contacts and enters each layer of the water collection wall 3, the water absorption layer 8 will be quickly saturated, and the excess water will continuously enter the infiltration pipe 5, and then enter the collection pipe 7 in the wall, and finally enter the centralized water collection well 14 for storage. The excess water will flow to the drainage step platform 9 through the drainage step slope 2. At this time, the drainage step platform 9 will collect a large amount of precipitation, and the water will naturally enter the water storage layer 13 in the annular water collection trough 10, and then enter the collection pipe 12 in the trough, and finally enter the centralized water collection well 14 for storage, avoiding excessive water absorption inside the drainage step platform 9.

[0038] In each of the above processes, the reverse slope step 4 can also ensure that the water flows from the slope to the inside of the drainage step, ensuring that the water will not flow out from the edge of the water collection wall 3, thereby ensuring the water storage effect. Valves are set at the connection points between the collection pipe 7 in the wall, the collection pipe 12 in the trough and the centralized water collection well 14, so it is possible to choose whether to store the water in the collection pipe separately or collect it in the centralized water collection well 14 by opening and closing the corresponding valves; in this way, when the water level in the centralized water collection well 14 is low, it is possible to ensure that there is water in the collection pipe at a high place, which is convenient for implementing the water replenishment process without the need to manually inject water into the collection pipe.

[0039] When the slope of the drainage step 2 begins to lack water, the water in the water absorption layer 8 in the water collection wall 3 and the water storage layer 13 in the annular water collection trough 10 will first penetrate into the step to supply water to the plants. When the water shortage continues, the water content of the water absorption layer 8 decreases, and the water in the infiltration pipe 5 in the water collection wall 3 will naturally seep out to replenish the water absorption layer 8, and then replenish the slope of the drainage step 2. When there is a slight water shortage, the water in the wall collection pipe 7 in the water collection wall 3 and the trough collection pipe 12 in the annular water collection trough 10 replenishes the slope of the drainage step 2; when there is a moderate water shortage, the water in the centralized water collection well 14 will be replenished to the slope of the drainage step 2 through the wall collection pipe 7. The entire scheme achieves the effect of long-term continuous water replenishment of the slope of the drainage step 2.

[0040] The entire water shortage process is from the slope 2 of the soil discharge step to the inside of the soil discharge step, while the water replenishment process is just the opposite, which can ensure slow and continuous water replenishment, which can not only meet the needs of slope vegetation, but also will not cause excessive water accumulation inside the step and affect stability. Since the upper water collection wall 3 is relatively low in height and has limited water storage capacity, the annular water collection trough 10 can make up for this problem at this time. The above water replenishment process completely relies on the capillary effect of water, does not require manual intervention, and is low in cost.

[0041] When there is a serious water shortage or the water level in the centralized water collection well 14 drops and cannot supply water to the collection pipe 7 in the wall, water is manually injected into the centralized water collection well 14, and the water enters the collection pipe 7 in the wall through the centralized water collection well 14 and then enters the slope 2 of the soil discharge step, so as to realize long-term continuous water supply to the entire slope, and reduce evaporation and runoff waste caused by surface irrigation. Each collection pipe and water collection well are controllable, so water can be accurately replenished according to the drought situation, reducing irrigation costs.

[0042] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A method for constructing a water-retaining dump in an open-pit mine, characterized in that: It includes three steps: constructing layered water collection walls, constructing annular water collection tanks and constructing centralized water collection wells; Constructing layered water collection walls: In the process of normally discarding the stripped materials of the open-pit mine to form the boundary open-pit mine dump (1), a water collection wall (3) is constructed in layers on the slope surface (2) of the first dumping step; when the height of the dumping step reaches the construction height of the first layer of the water collection wall (3), a reverse slope step (4) with a slope opposite to the slope surface (2) of the dumping step is constructed at the edge of the step, and the reverse slope step (4) is continuously arranged along the dumping step to both ends, and then 1-2 layers of infiltration pipes (5) are arranged on the reverse slope step (4), and each layer has multiple infiltration pipes (5) arranged side by side. Fine sand is filled between the infiltration pipes (5) as a protective layer (6), and at the end of the reverse slope step (4), next to the infiltration pipe (5) An inner wall collecting pipe (7) is provided, and the infiltration pipe (5) and the inner wall collecting pipe (7) are continuously arranged along the soil discharge step until both ends are closed, and a water absorption layer (8) is laid and constructed outside the protective layer (6) and the inner wall collecting pipe (7) until the height of the water collection wall (3) of that layer is reached, at which time the construction of the first layer of the water collection wall (3) is completed; then, the open-pit mine stripping materials are normally discharged on the plane where the first layer of the water collection wall (3) is located, and when the height of the soil discharge step is gradually increased to reach the construction height of the second layer of the water collection wall (3), the second layer of the water collection wall (3) is constructed in accordance with the method of constructing the first layer of the water collection wall (3), and so on, until the top layer of the water collection wall (3) is constructed; Constructing a circular sump: After the first soil discharge step reaches the final construction height, an annular water collection trough (10) is excavated on the soil discharge step platform (9) at a distance of 3 m from the surrounding boundaries, a permeable geotextile (11) is laid on the bottom and two side surfaces of the annular water collection trough (10), a continuous in-trough collection pipe (12) is laid on the permeable geotextile (11) on the bottom surface, and the remaining space in the annular water collection trough (10) is filled with materials as a water storage layer (13); Constructing centralized water collection wells: A centralized water collection well (14) is excavated downwards at both ends of one side close to the outer boundary of the soil discharge step platform (9), and the wall collection pipe (7) and the trough collection pipe (12) in each layer of the water collection wall (3) are connected to the centralized water collection well (14) nearby; thus, the first soil discharge step is constructed; According to the above method, the second soil discharge step is constructed on the first soil discharge step; and so on, until the last soil discharge step is constructed.

2. The method for constructing a water-retaining dump for an open-pit mine according to claim 1, characterized in that: In the step of constructing the layered water collection wall, the height of the lowest water collection wall (3) is 2.5-3.5 m, the top width is 4.5-5.5 m, the height of the starting end of the reverse slope step (4) in the lowest water collection wall (3) is 0.5 m, and the slope is 3%; the intervals between adjacent water collection walls (3) are the same, both 3-5 m.

3. A method for constructing a water-retaining dump for an open-pit mine according to claim 2, characterized in that: The height of the upper water collection wall (3) is 0.5 m lower than the height of the lower water collection wall (3), and the height of the reverse slope step (4) in the upper water collection wall (3) is 0.1 m lower than the height of the reverse slope step (4) in the lower water collection wall (3); the lower limit height of the water collection wall (3) is 1 m, and the lower limit height of the reverse slope step (4) is 0.2 m.

4. The method for constructing a water-retaining dump in an open-pit mine according to claim 1, characterized in that: In the step of constructing the centralized water collection wells, one more centralized water collection well (14) is excavated for every 1 km the distance between the centralized water collection wells (14) at both ends exceeds, and the distances between all the centralized water collection wells (14) are equal.

5. The method for constructing a water-retaining dump in an open-pit mine according to claim 1, characterized in that: Valves are provided at the points where the collecting pipe (7) in the wall, the collecting pipe (12) in the trough and the centralized water collection well (14) are connected.

6. The method for constructing a water-retaining dump in an open-pit mine according to claim 3, characterized in that: The cross section of the water collection wall (3) is trapezoidal and the slope is the natural repose angle of the material.

7. The method for constructing a water-retaining dump in an open-pit mine according to claim 1, characterized in that: The wall collecting pipe (7) and the tank collecting pipe (12) are both perforated rubber tubes.

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