Tailing pond closed reservoir efficient energy-saving combined drainage device and method

Abstract

The invention discloses an efficient energy-saving combined drainage device and method for closing a tailings pond, and belongs to the technical field of mine tailings. The high-pressure water gun gully system comprises a drainage ditch, a drainage well and a sludge discharge pipeline, one end of the drainage ditch communicates with the drainage well, the other end of the drainage ditch is connected with an open water area, and the middle section of the drainage ditch communicates with an upstream deposition section of the open water area through the sludge discharge pipeline; the fishbone-shaped matts drainage structure comprises main drainage ditches and secondary drainage ditches, and the main drainage ditches and the secondary drainage ditches are arranged in a fishbone matts shape; the light well point dewatering drainage system comprises a water collecting main pipe and dewatering well pipes, and the water collecting main pipe is arranged in the arrangement direction of the dewatering well pipes. The problems that in an existing tailing pond closing project, the beach face bearing capacity is insufficient, the regional draining consolidation effect is poor, and a deep water-containing area is difficult to treat are solved. The beach face bearing capacity of the tailings pond is improved, the construction continuity is ensured, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of mine tailings, and in particular to a tailings pond closed reservoir high-efficiency energy-saving combined drainage device and method. Background Art

[0002] Tailings ponds are important facilities for mining companies to discharge tailings (i.e., waste slag and wastewater remaining after mineral processing). With the gradual depletion of mining resources or policy-driven closures, tailings ponds need to be closed to ensure environmental safety and land reclamation. However, the closure of tailings ponds faces many technical challenges. Due to the sedimentation characteristics of coarse and fine particles during the tailings discharge process, a large amount of open water areas, such as ponds or lakes, are often formed at the bottom of the tailings pond. The tailings and mud at the top of the tailings pond contain a large amount of interstitial water, resulting in insufficient bearing capacity of the beach surface. During the construction process, machinery and equipment and transport vehicles are easily trapped in the tailings and mud, posing a major safety hazard.

[0003] At present, the common methods for closing and draining tailings ponds mainly include traditional means such as mechanical manual trenching and natural drainage. However, when mechanical manual trenching is used, equipment and personnel are easily trapped in the mud, which increases the difficulty and risk of construction. For deep water-bearing areas, traditional methods are difficult to effectively lower the groundwater level, affecting subsequent construction. Traditional methods require a lot of manpower and material resources, resulting in high construction costs, and a large amount of subsequent maintenance work, especially the large amount of backfill in open water areas, which increases the cost of long-term management. Summary of the invention

[0004] The purpose of the present invention is to provide a tailings pond closed and energy-saving combined drainage device and method, which can improve the beach bearing capacity of the tailings pond, ensure the continuity of construction, reduce construction costs, improve construction efficiency, shorten construction period, and solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A tailings pond closed reservoir high-efficiency energy-saving combined drainage device, comprising:

[0007] The high-pressure water gun gully flushing system includes a drainage ditch, a drainage well, a sludge pump and a sludge discharge pipeline. One end of the drainage ditch is connected to the drainage well, and the other end is connected to the open water area. The middle section of the drainage ditch is connected to the upstream sedimentation section of the open water area through a sludge discharge pipeline, and a sludge discharge pipeline is provided with a sludge pump;

[0008] The fishbone-shaped grid drainage structure includes a main drain ditch and a secondary drain ditch. The main drain ditch is connected to the drainage well. The two sides of the main drain ditch are connected to the secondary drain ditch. The main drain ditch and the secondary drain ditch are arranged in a fishbone grid shape.

[0009] The light well point dewatering drainage system includes a water collection main pipe and a dewatering well pipe. The water collection main pipe is arranged along the arrangement direction of the dewatering well pipe, and the water collection main pipe is connected with the dewatering well pipe through a connecting pipe. A filter pipe is provided at the bottom of the dewatering well pipe, and the filter pipe is wrapped with one or two layers of filter mesh and a layer of geotextile. The upper part of the dewatering well pipe is provided with clay soil for backfilling and sealing, and the inside of the dewatering well pipe is filled with melon seed slices.

[0010] Preferably, the main water collection pipe is laid horizontally below the ground surface, with a diameter of 100 mm and a length of not less than 50 m.

[0011] Preferably, a vacuum water pump is provided at one end of the water collecting main pipe, and the vacuum degree is not less than 60 kPa.

[0012] Preferably, the filter tube has a length of 1.2 to 1.5 m and an opening rate of not less than 12%.

[0013] Preferably, the top of the precipitation well pipe is not lower than the ground level, and the bottom of the precipitation well pipe extends to the aquifer.

[0014] A tailings pond closed reservoir high-efficiency energy-saving combined drainage method is implemented based on a tailings pond closed reservoir high-efficiency energy-saving combined drainage device, comprising:

[0015] For large areas of open water in tailings ponds, use a high-pressure water gun gully flushing system;

[0016] For water-bearing areas within 3 meters of tailings and mud, a fishbone-shaped grid drainage structure is used;

[0017] For water-bearing areas more than 3 meters away from tailings and mud, a light well point dewatering and drainage system is used.

[0018] Preferably, the construction process of the high-pressure water gun gully flushing system is as follows:

[0019] Plan a reasonable gully path on the surface of the tailings pond, ensuring that one end is connected to the open water area and the other end is connected to the tailings pond drainage well;

[0020] Use a high-pressure water gun to spray high-pressure water along a predetermined path to form a drainage ditch;

[0021] The flowing silt generated during the gullying process is pumped to the upstream of the open water area by silt pumps for deposition, reducing the amount of backfill in the open water area in the later stage, raising the bottom elevation of the open water area, and promoting the gravity flow of pond water to the drainage well.

[0022] Preferably, the construction process of the fishbone-shaped grid drainage structure is as follows:

[0023] Use ship-digger equipment to dig the main drainage ditch in a specific direction to ensure that water can flow from low places to high places and be discharged through the drainage well. The slope of the main drainage ditch is required to ensure that water can flow by itself;

[0024] Secondary drain ditches are dug non-vertically from high to low on both sides of the main drain ditch and connected to the main drain ditch to form a herringbone layout to ensure that the water in the secondary drain ditch flows smoothly into the main drain ditch.

[0025] Preferably, the construction process of the light well point dewatering and drainage system is as follows:

[0026] Conduct a comprehensive survey of the deep water-bearing areas of the tailings pond and determine the layout plan for the drainage well pipes;

[0027] Drill holes at selected locations, with the diameter of each drainage well pipe being approximately 300 mm;

[0028] Install the filter pipe in each drilled hole, wrap the filter screen and a layer of geotextile on the outside, and then put the precipitation well pipe in place, making sure its top is not lower than the ground;

[0029] Use medium-coarse sand as filter material to fill the space around the filter pipe, with the filling volume not less than 95%. Use clay soil to backfill and seal the top of the precipitation well pipe;

[0030] Lay the water collecting main pipe horizontally under the ground surface and connect it to the precipitation well pipe through a connecting pipe;

[0031] A vacuum water pump is installed at one end close to the water collection main to form a complete water pumping network.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention uses a high-pressure water gun gully system, a fishbone-shaped grid drainage structure and a light well point dewatering system in a coordinated manner, which is suitable for the effective treatment of water-containing areas of different depths in the tailings pond, effectively solves the drainage problem in the tailings pond closure project, improves the beach bearing capacity of the tailings pond, ensures construction continuity and safety, reduces construction costs, improves construction efficiency, and shortens construction period.

[0034] 2. The present invention forms a drainage ditch on the surface of the tailings pond by using a high-pressure water gun, with one end connected to the open water area and the other end connected to the tailings pond drainage well. The flowing sludge generated in this process is pumped to the upstream of the open water area for deposition, reducing the amount of backfill in the later stage, raising the elevation of the pond bottom, and promoting the gravity flow of pond water to the drainage well. This method avoids the risk of equipment and personnel being trapped in sludge during traditional mechanical manual ditch digging.

[0035] 3. The present invention targets the water-bearing area within 3 meters of tailings and mud, and uses ship-digger equipment to dig the main drainage ditch and the secondary drainage ditch in a specific direction to form a fishbone-shaped layout. This design not only improves the effect of regional drainage consolidation, but also has a low cost. The main and secondary drainage ditches are connected to ensure that water can flow from low to high and be discharged through the drainage well.

[0036] 4. In the present invention, the light well point dewatering system can effectively extract groundwater to the surface for external discharge by arranging multiple dewatering well pipes in the deep water-bearing area of ​​the tailings pond, which helps to significantly lower the groundwater level and reduce the pore water pressure in the tailings, thereby preventing mechanical equipment from sinking into silt and tailings during construction and ensuring construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the high-pressure water gun gully flushing system of the present invention;

[0038] Figure 2 It is a schematic diagram of the fishbone-shaped grid drainage structure of the present invention;

[0039] Figure 3 It is a schematic plan view of the light well point dewatering and drainage system of the present invention;

[0040] Figure 4 It is a longitudinal cross-sectional view of the precipitation well pipe of the present invention.

[0041] In the figure: 1. High-pressure water gun gully system; 11. Drainage ditch; 12. Drainage well; 13. Sludge pump; 14. Sludge drainage pipeline; 15. Open water area; 2. Fishbone-shaped grid drainage structure; 21. Main drain ditch; 22. Secondary drain ditch; 3. Light well point precipitation drainage system; 31. Water collection main pipe; 32. Precipitation well pipe; 33. Filter pipe; 34. Geotextile; 35. Connecting pipe; 36. Clay; 37. Melon seed slices; 38. Vacuum water pump; 39. Saturated tailings formation. DETAILED DESCRIPTION

[0042] 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.

[0043] In order to solve the problems of insufficient beach bearing capacity, poor regional drainage and consolidation effect, difficulty in handling deep water-bearing areas, and great construction safety hazards in existing tailings pond closure projects, this embodiment provides the following technical solutions:

[0044] A tailings pond closed reservoir high-efficiency energy-saving combined drainage device, comprising:

[0045] See also Figure 1 , high pressure water gun gully system 1, used to drain large areas of open water from tailings pond 4.

[0046] The high-pressure water gun gully flushing system 1 includes a drainage ditch 11, a drainage well 12, a sludge pump 13 and a sludge discharge pipe 14. One end of the drainage ditch 11 is connected to the drainage well 12, and the other end is connected to the open water area 15. The middle section of the drainage ditch 11 is connected to the upstream sedimentation section of the open water area 15 through the sludge discharge pipe 14, and the sludge discharge pipe 14 is provided with a sludge pump 13.

[0047] The drainage ditch 11 is flushed out with a high-pressure water gun instead of mechanical manual digging, so as to avoid the hidden danger of machinery and personnel being trapped in the silt during the construction process; the flowing silt in the drainage ditch 11 is sent to the upstream of the open water area 15 through the silt discharge pipe 14 under the action of the silt pump 13 for deposition, thereby reducing the backfill volume of the open water area 15 in the later stage. At the same time, the deposited silt raises the elevation of the pond bottom of the open water area 15, further promoting the self-flow of pond water through the drainage ditch 11 to the drainage well 12.

[0048] See also Figure 2 , the fishbone-shaped grid drainage structure 2 is used to discharge the water within 3 meters of tailings and mud.

[0049] The herringbone-shaped grid drainage structure 2 includes a main drain ditch 21 and a secondary drain ditch 22. The main drain ditch 21 is connected to the drainage well 12. Secondary drain ditches 22 are connected to both sides of the main drain ditch 21. The main drain ditch 21 and the secondary drain ditch 22 are arranged in a herringbone grid shape.

[0050] along Figure 2 In the G0-G1-G4-G5 direction, a main drainage ditch 21 is dug by boat, and the slope requires that the water from G5 to G0 can flow by itself and be discharged through the 6A6B drainage well 12. Secondary drainage ditches 22 are dug non-vertically from high to low on both sides of the main drainage ditch 21 until they are connected to the main drainage ditch 21; the main drainage ditch 21 and the secondary drainage ditch 22 are in a fishbone grid shape; the use of special equipment boat digging has the advantage of good regional drainage and sludge consolidation effect, and more importantly, low cost.

[0051] See also Figure 3 , light well point dewatering drainage system 3, used to discharge the water content of tailings and mud 3 meters away, reduce the pore water pressure in the tailings, and improve the bearing capacity of the foundation.

[0052] The light well point dewatering drainage system 3 comprises a water collecting main pipe 31 and a dewatering well pipe 32. The water collecting main pipe 31 is laid horizontally under the ground surface, has a diameter of 100 mm and a length of not less than 50 m.

[0053] The main water collecting pipe 31 is arranged along the arrangement direction of the precipitation well pipes 32 so as to collect groundwater from each precipitation well pipe 32 .

[0054] The precipitation well pipes 32 are arranged in rows in specific areas of the tailings pond 4 as required, with a row spacing of about 10 m; the distance between the precipitation well pipes 32 is about 1.2 m, ensuring that the entire area requiring precipitation is covered.

[0055] The top of the precipitation well pipe 32 is flush with the ground or slightly above the ground, and the bottom of the precipitation well pipe 32 extends to the aquifer, ensuring that groundwater can be effectively extracted.

[0056] The specific technical parameters of the precipitation well pipe 32 are as follows:

[0057] Determine the burial depth L:

[0058] L=S+Δh+i*r+l

[0059] Among them, the drawdown S, the exposed height of the well point pipe Δh, the length l of the filter pipe 33, the distance r between the double row center line and the well point, and the double row drainage force slope i are key parameters.

[0060] Determine the precipitation equivalent radius r0:

[0061] r0=1.14(a+b) / 4

[0062] Wherein a is the layout length of the precipitation well pipe 32, and b is the layout width of the precipitation well pipe 32;

[0063] Determine the influence radius R of the precipitation well pipe 32:

[0064] R=2S×(hK)^1 / 2

[0065] Where S is the water level drawdown and h is the layer thickness;

[0066] Determine the single well water output q1:

[0067] q1=120×π×rs×L×K^1 / 3

[0068] Where rs is the filter diameter, L is the water inlet length, and K is the permeability coefficient;

[0069] The total water yield Q under the condition of non-complete well in homogeneous aquifer is:

[0070] Q=1.366K*S*{(l+S) / log(2b / r0)+l / [log(0.66*l / r0)+0.22arsh(0.44*l / b)]}

[0071] See also Figure 4 The bottom of the precipitation well pipe 32 is provided with a filter tube 33, which is 1.2-1.5 m long and has an opening rate of not less than 12%; the filter tube 33 is wrapped with one or two layers of filter screen and a layer of geotextile 34 (200-400 g / m 2 ), use medium-coarse sand with reasonable grading as filter material, and the filling amount of filter material should be not less than 95% to prevent fine particles from clogging the filter tube 33.

[0072] The upper part of the precipitation well pipe 32 is about 1.0m backfilled and sealed with clay 36 to prevent surface water from infiltrating and affecting the precipitation effect; the inside of the precipitation well pipe 32 is filled with melon seed slices 37.

[0073] The precipitation well pipes 32 are indirectly connected to each other through the water collecting main pipe 31, and the sealing treatment of the upper part of the precipitation well pipe 32 is completed independently, but it is necessary to ensure that the overall sealing performance is not affected.

[0074] A vacuum water pump 38 is provided at one end of the water collecting main pipe 31. The vacuum water pump 38 is placed in a place convenient for operation and maintenance. The vacuum degree should be no less than 60 kPa to ensure that groundwater can be effectively extracted from the precipitation well pipe 32 and discharged to the designated discharge location through the water collecting main pipe 31. The vacuum water pump 38 is also equipped with a backup power supply to prevent the main power supply failure from causing pumping interruption.

[0075] The water collecting main pipe 31 is connected to the precipitation well pipe 32 through the connecting pipe 35 to form a complete water pumping network. The connecting pipe 35 is usually made of a hose or other materials suitable for the underground environment to ensure good sealing and durability.

[0076] It should be noted that the pipe connection points included in the light well point dewatering and drainage system 3 should be sealed and free of air leakage; the dewatering should not be stopped during the dewatering process, otherwise the surrounding water will quickly flow back, resulting in all previous efforts being wasted, so the power supply should be guaranteed or a backup power supply should be used; after the start of pumping, the water level in the observation well should be observed every day until the groundwater level drops to about 6m before other operations can be carried out.

[0077] A tailings pond closed reservoir high-efficiency energy-saving combined drainage method is implemented based on a tailings pond closed reservoir high-efficiency energy-saving combined drainage device, comprising:

[0078] For large areas of open water in the tailings pond, use a high-pressure water gun gully flushing system1;

[0079] For water-bearing areas within 3 meters of tailings and mud, a fishbone-shaped grid drainage structure is used2;

[0080] For water-bearing areas more than 3 meters away from tailings and mud, a light well point dewatering and drainage system is used3.

[0081] The construction process of high-pressure water gun gully system 1 is as follows:

[0082] Plan a reasonable gully path on the surface of the tailings pond, ensuring that one end is connected to the open water area 15 and the other end is connected to the tailings pond drainage well 12;

[0083] Using a high-pressure water gun to spray high-pressure water along a predetermined path to form a drainage ditch 11;

[0084] The flowing silt generated during the gullying process is pumped to the upstream of the open water area 15 by the silt pump 13 for deposition, thereby reducing the amount of backfill in the open water area 15 in the later stage, raising the bottom elevation of the open water area 15, and promoting the gravity flow of pond water to the drainage well 12.

[0085] The construction process of the fishbone-shaped grid drainage structure 2 is as follows:

[0086] Use ship-digger equipment to dig the main drainage ditch 21 along a specific direction to ensure that water can flow from low places to high places and be discharged through the drainage well 12. The slope of the main drainage ditch 21 is required to ensure that water can flow by itself;

[0087] Secondary drain ditches 22 are non-vertically dug from high to low on both sides of the main drain ditch 21 and connected to the main drain ditch 21 to form a fishbone-shaped layout to ensure that the water in the secondary drain ditch 22 flows smoothly into the main drain ditch 21 .

[0088] The construction process of the light well point dewatering and drainage system 3 is as follows:

[0089] Conduct a comprehensive survey of the deep water-bearing area of ​​the tailings pond and determine the layout plan of the drainage well pipe 32;

[0090] Drilling is performed at the selected location, and the diameter of the hole of each drainage well pipe 32 is about 300 mm;

[0091] Install a filter tube 33 in each drilled hole, wrap the filter screen and a layer of geotextile 34 on the outside, and then put the precipitation well pipe 32 in place, ensuring that its top is not lower than the ground;

[0092] Use medium-coarse sand as filter material to fill the space around the filter tube 33, with the filling volume not less than 95%. The upper part of the precipitation well pipe 32 is backfilled and sealed with clay soil 36;

[0093] The water collecting main pipe 31 is laid horizontally under the ground surface and connected to the precipitation well pipe 32 through the connecting pipe 35;

[0094] A vacuum water pump 38 is installed at one end close to the water collecting main pipe 31 to form a complete water pumping network.

[0095] Working principle: The present invention uses a high-pressure water gun gully system 1 for large areas of open water in the tailings pond; for water-bearing areas within 3 meters of tailings and tailings, a fishbone-shaped grid drainage structure 2 is used; for water-bearing areas beyond 3 meters of tailings and tailings, a light well point precipitation drainage system 3 is used. A drainage ditch 11 is formed on the surface of the tailings pond by using a high-pressure water gun, one end of which is connected to the open water area 15, and the other end is connected to the tailings pond drainage well 12. The flowing sludge generated in this process is sent to the upstream of the open water area 15 for deposition via a sludge pump 13, which reduces the amount of backfilling in the later stage and raises the elevation of the pond bottom. For water-bearing areas within 3 meters of tailings and tailings, ship excavation equipment is used to excavate the main drainage ditch 21 and the secondary drainage ditch 22 in a specific direction to form a fishbone-shaped layout. This design not only improves the effect of regional drainage consolidation, but also has a lower cost. For the deep water-bearing area beyond 3 meters of tailings and mud, filter pipes 33 and well pipes 32 are installed by drilling holes, and medium-coarse sand with reasonable grading is used as filter material, and the upper part is sealed with clay 36. The water collection main pipe 31 is connected to each well point, and the vacuum pump 38 extracts the groundwater and discharges it through the water collection main pipe 31.

[0096] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0097] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A tailings pond closed storage high-efficiency energy-saving combined drainage device, characterized in that: include: A high-pressure water gun gully flushing system (1) comprises a drainage ditch (11), a drainage well (12), a sludge pump (13) and a sludge discharge pipe (14); one end of the drainage ditch (11) is connected to the drainage well (12), and the other end is connected to an open water area (15); the middle section of the drainage ditch (11) is connected to an upstream sedimentation section of the open water area (15) via a sludge discharge pipe (14); and the sludge discharge pipe (14) is provided with a sludge pump (13); The fishbone-shaped grid drainage structure (2) comprises a main drain ditch (21) and a secondary drain ditch (22), wherein the main drain ditch (21) is connected to a drainage well (12), and the secondary drain ditch (22) is connected to both sides of the main drain ditch (21), and the main drain ditch (21) and the secondary drain ditch (22) are arranged in a fishbone grid shape; A light well point drainage system (3) comprises a water collecting main pipe (31) and a drainage well pipe (32). The water collecting main pipe (31) is arranged along the arrangement direction of the drainage well pipe (32). The water collecting main pipe (31) is connected to the drainage well pipe (32) through a connecting pipe (35). A filter pipe (33) is arranged at the bottom of the drainage well pipe (32). The filter pipe (33) is wrapped with one or two layers of filter screen and a layer of geotextile (34). The upper part of the drainage well pipe (32) is provided with clay soil (36) for backfilling and sealing. The interior of the drainage well pipe (32) is filled with melon seed slices (37).

2. A tailings pond closed reservoir high-efficiency energy-saving combined drainage device according to claim 1, characterized in that: The water collecting main pipe (31) is laid horizontally under the ground surface, has a diameter of 100 mm and a length of not less than 50 m.

3. A tailings pond closed reservoir high-efficiency energy-saving combined drainage device according to claim 2, characterized in that: A vacuum water pump (38) is provided at one end of the water collecting main pipe (31), and the vacuum degree is not less than 60 kPa.

4. The tailings pond closed storage high-efficiency energy-saving combined drainage device according to claim 3 is characterized in that: The filter tube (33) has a length of 1.2 to 1.5 m and an opening rate of not less than 12%.

5. A tailings pond closed reservoir high-efficiency energy-saving combined drainage device according to claim 6, characterized in that: The top of the precipitation well pipe (32) is not lower than the ground level, and the bottom of the precipitation well pipe (32) extends to the aquifer.

6. A tailings pond closed reservoir high-efficiency energy-saving combined drainage method, based on a tailings pond closed reservoir high-efficiency energy-saving combined drainage device according to any one of claims 1 to 5, characterized in that: include: For large areas of open water in tailings ponds, use a high-pressure water gun gully flushing system (1); For water-bearing areas within 3 meters of tailings and mud, a fishbone-shaped grid drainage structure (2) is used; For water-bearing areas more than 3 meters away from tailings and mud, a light well point dewatering and drainage system (3) is used.

7. A tailings pond closed reservoir high-efficiency energy-saving combined drainage method according to claim 6, characterized in that: The construction process of the high-pressure water gun gully flushing system (1) is as follows: Plan a reasonable gully path on the surface of the tailings pond, ensuring that one end is connected to the open water area (15) and the other end is connected to the tailings pond drainage well (12); Using a high-pressure water gun to spray high-pressure water along a predetermined path to form a drainage ditch (11); The flowing silt generated during the gullying process is pumped to the upstream of the open water area (15) by a silt pump (13) for deposition, thereby reducing the amount of backfill in the open water area (15) at a later stage and raising the bottom elevation of the open water area (15), thereby promoting the self-flow of pond water to the drainage well (12).

8. A tailings pond closed reservoir high-efficiency energy-saving combined drainage method according to claim 7, characterized in that: The construction process of the fishbone-shaped grid drainage structure (2) is as follows: The main drainage ditch (21) is excavated along a specific direction using a ship-digger to ensure that water can flow from a low place to a high place and be discharged through the drainage well (12). The slope of the main drainage ditch (21) is required to ensure that water can flow by itself. Secondary drain ditches (22) are non-vertically excavated from high to low on both sides of the main drain ditch (21) and connected to the main drain ditch (21) to form a fishbone-shaped layout, thereby ensuring that water in the secondary drain ditch (22) flows smoothly into the main drain ditch (21).

9. A tailings pond closed reservoir high-efficiency energy-saving combined drainage method according to claim 8, characterized in that: The construction process of the light well point dewatering and drainage system (3) is as follows: Conduct a comprehensive survey of the deep water-bearing area of ​​the tailings pond and determine the layout plan of the drainage well pipe (32); Drilling holes at selected locations, with the diameter of each drainage well pipe (32) being about 300 mm; Install a filter tube (33) in each drilled hole, wrap the filter screen with a layer of geotextile (34) on the outside, and then put the precipitation well pipe (32) in place to ensure that its top is not lower than the ground; Use medium-coarse sand as filter material to fill the space around the filter tube (33), with the filling volume not less than 95%. The upper part of the precipitation well pipe (32) is backfilled and sealed with clay soil (36); The water collecting main pipe (31) is horizontally laid under the ground surface and connected to the precipitation well pipe (32) via a connecting pipe (35); A vacuum water pump (38) is installed at one end close to the water collecting main pipe (31) to form a complete water pumping network.

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