A new method to rebuild the flood drainage system in the used tailings pond

Abstract

The present invention discloses a new method for reconstructing a flood discharge system in a used tailings pond. The reconstructed flood discharge system is composed of a steel blade angle caisson (1), a stilling well (4), a pile foundation (6), an annular cap (7), and a new flood discharge well (8); the stilling well (4) is dug down in layers in the steel blade angle caisson (1), and a reinforced concrete wall is cast to form a net circular section; the pile foundation (6) is arranged in a circular ring shape on the periphery of the steel blade angle caisson (1); the annular cap (7) is cast and supported on the pile foundation (6); and the new flood discharge well (8) is constructed and supported on the annular cap (7). The present invention utilizes the caisson to transform the original drainage culvert, which can effectively shorten the construction period and reduce the construction cost. It can not only meet the normal tailing discharge requirements of the tailings pond, but also ensure the need for flood discharge in the heavy rainfall season, and has good economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine tailings pond flood discharge system management, and specifically relates to a new method for reconstructing a flood discharge system in a used tailings pond, and is particularly suitable for modifying a drainage culvert after the original flood discharge system of the tailings pond is damaged, so as to reconstruct the flood discharge system. Background Art

[0002] The main function of the tailings pond flood discharge system is to control the flood in the reservoir catchment area and discharge it safely and effectively outside the reservoir, preventing dam breach accidents caused by floods, which plays a vital role in the safe operation of the tailings pond.

[0003] At present, most of the tailings ponds with large catchment areas use a "drainage well + drainage culvert" type of flood discharge system. Especially for tailings ponds with a long operating life, the safety of the flood discharge system is very important. Once there is a safety hazard in the flood discharge system, such as the tilt of the drainage well body or damage to the drainage culvert structure, the flood discharge system needs to be managed in a timely manner.

[0004] Chinese patent application 201610715699.9 discloses a flood discharge system suitable for upstream dry tailings ponds. The flood discharge system includes a flood discharge shaft, a flood control water collection pool, a return water hole, and an anti-filtration layer. The specific structure is as follows: a flood control water collection pool is built outside the flood discharge shaft, and the flood discharge shaft adopts a metal structure well body and a reinforced concrete well seat. The upper and lower combined structure, the well body is opened with a return water hole, and an anti-filtration layer is arranged around the well body. The flood discharge system can collect flood water in the flood control water collection pool, quickly increase the depth of the flood water at the flood discharge shaft, so that the flood discharge shaft quickly reaches the state of wellhead weir flow, increases the discharge capacity, reduces the flood discharge time, and can drain all the flood in the tailings pond. This reduces the infiltration of floods in the reservoir area and avoids the appearance of saturated tailings weak interlayers or unstable infiltration lines due to the large infiltration depth of the flood. However, the flood discharge system is only suitable for use in the flood discharge system of the upstream dry tailings pond, and it is difficult to adapt to the needs of rapid and large-flow flood discharge in the tailings pond with a large catchment area during the rainy season.

[0005] At present, the more common solution for the management of mine tailings pond flood discharge systems is to build a new flood discharge system. However, the construction period of a new complete flood discharge system is long and difficult, which makes it difficult to meet the timeliness of emergency management of the flood discharge system, and it also imposes a heavy burden on the operating costs of the enterprise. Summary of the invention

[0006] The purpose of the present invention is to address the problems of long construction period and great difficulty in building a new flood drainage system after the flood drainage system of an existing tailings pond is damaged. By transforming the drainage culverts in the original flood drainage system of the tailings pond, a new method for rebuilding the flood drainage system in an existing tailings pond is provided, which is convenient to construct, economical and effective, safe and stable, so as to meet the needs of quickly, efficiently and safely rebuilding the flood drainage system and reduce the construction difficulty during the new construction of the flood drainage system of the tailings pond.

[0007] To achieve the above-mentioned object of the present invention, a new method for reconstructing a flood discharge system in a tailings pond of the present invention is implemented by the following technical scheme:

[0008] The invention discloses a new method for reconstructing a flood discharge system in a used tailings pond. The reconstructed flood discharge system is composed of a steel blade angle caisson, a stilling well, a pile foundation, an annular cap, and a new flood discharge well. The stilling well is dug down in layers in the steel blade angle caisson, and a reinforced concrete is used to cast a protective wall to form a net circular section. The pile foundation is arranged in a circular ring shape on the periphery of the steel blade angle caisson. The annular cap is cast and supported on the pile foundation. The new flood discharge well is constructed and supported on the annular cap, and the following steps are adopted for implementation:

[0009] S1 Construction preparation

[0010] First, according to the location of the damaged tailings pond's flood discharge well and the original drainage culvert buried location, determine the location where the flood discharge system needs to be rebuilt; fill the pond with earthwork to build the connecting road and construction platform to the location where the flood discharge system needs to be rebuilt;

[0011] S2 Steel blade caisson sinks under its own weight

[0012] After the filling and surveying and setting out of the connecting roads and construction platforms are completed, the steel blade angle caisson is sunk by its own weight to seal the bottom; angle steel is welded at the blade foot of the steel blade angle caisson, and the steel blade angle caisson is sunk to the design elevation. The original drainage culvert position is explored by the method of probing at the center and both sides. After the steel blade angle caisson sinks to the design elevation and the settlement is stable, concrete is used to seal the bottom, and the strength of the bottom sealing concrete is required to be not less than 75% of the design strength before the next step of construction;

[0013] S3 Grouting area drilling grouting

[0014] The grouting holes are arranged in layers along the outer ring of the steel blade angle caisson, and inclined grouting is adopted from the outside to the inside to form a grouting area. The grouting holes are closed and the upward hole blocking grouting is adopted from bottom to top. After the grouting is completed, the permeability coefficient of the grouting body is not less than 1 Lu Rong, and the strength of the grouting body is not less than 2MPa.

[0015] S4 Energy Dissipation Well Construction

[0016] The energy dissipation well is excavated in layers from the bottom of the steel blade angle caisson, and the retaining wall is cast with reinforced concrete to form a circular foundation pit section; the original drainage culvert is cut within the excavation range of the foundation pit, and the concrete at the joint between the original drainage culvert and the energy dissipation well is manually chiseled off, the steel bars are retained, and the original drainage culvert is overlapped with the steel bars at the bottom of the energy dissipation well, and then cast with concrete to seal it;

[0017] S5 Pile foundation construction

[0018] The pile foundation is laid in the filled construction platform. The pile foundation is symmetrically arranged around the stilling well and on both sides of the original drainage culvert. The pile foundation must enter the underlying foundation bearing layer.

[0019] S6 Annular Cap Construction

[0020] The annular cap is constructed on a well-filled construction platform. The annular cap adopts a reinforced concrete structure. Before tying the steel bars, the floating slurry part of the pile foundation pile head is chiseled out first, and the pile body and its main reinforcement are buried inside the annular cap. The concrete of the annular cap is poured once, and the concrete is preferably poured into the groove by the flat paving method. After the strength of the concrete is not less than 70% of the design value after pouring, the upper new flood discharge well is constructed;

[0021] S7 New flood drainage well construction

[0022] The new drainage well is constructed on the annular pedestal. The well body is a reinforced concrete structure. The inner diameter R of the new drainage well is calculated according to the "Design Code for Tailings Facilities" (GB 50863-2013), and the well body structural parameters must meet the flood prevention and drainage requirements.

[0023] Research shows that the steel blade angle caisson is preferably made of C35 reinforced concrete. According to the relevant provisions of the "Design Code for Tailing Facilities" (GB 50863-2013), the relevant size parameters are calculated. The inner diameter of the new flood discharge well is recorded as R, and the inner diameter of the steel blade angle caisson is 1.5~2.0R, the wall thickness δ is 0.35~0.5m, and the height is 3.0~5.5m; the blade angle welding angle steel of the steel blade angle caisson has an angle steel size of ∠(200~500)mm*(200~500)mm*(9~12)mm, that is, the angle steel size is ∠200mm*200mm*9mm~∠500mm*500mm*12mm, and ∠200mm*200mm*10mm~∠500mm*500mm*10mm is preferred. Under this structural parameter, it can meet the sinking requirements while achieving the designed strength and displacement requirements.

[0024] In order to improve the stability of the foundation and meet the reliability requirements of the reconstructed flood drainage system, the common central axis of the steel blade caisson, the energy dissipation well and the new flood drainage well is used as the radius, the grouting area ranges from Dr = 4 to 6R, the grouting hole diameter is φ = 90 to 130 mm, and the layers are arranged in layers along the annular plane, with 2 to 3 layers and a layer spacing of φ d =1.5m~2.5m, grouting depth h=5m~10m, grouting is inclined from outside to inside, and the inclination angle is 55º~65º. Under this technical parameter, the system reliability and construction economy are most reasonable and optimized.

[0025] The energy dissipation well is dug in layers in the steel blade angle caisson, with a layered digging height of 0.5m~1.0m, and C25 reinforced concrete is used to cast the retaining wall, with a thickness of 0.2m~0.3m and a height of 0.5m~1.0m. After the retaining wall is cast, a circular section with a net section diameter of 1.0m~2.0m is formed.

[0026] In order to improve the stability of the foundation, the pile foundation is a C40 bored cast-in-place pile with a pile body diameter ranging from 500 to 700 mm, preferably 600 mm; the diameter of the pile area is 2R~4R, and the pile length L=10~20m, which can be specifically calculated and determined according to the "Technical Code for Building Pile Foundations" (JGJ 94-2008) and other regulations.

[0027] Furthermore, the new flood drainage well is a C35 reinforced concrete structure with an inner diameter of 1.8 to 2.3 m and a wall thickness of 0.27 to 0.34 m.

[0028] Furthermore, the annular foundation is a C35 reinforced concrete structure, the inner diameter D1 is the same as the diameter of the energy dissipation well, the outer diameter D2=3~5R, and the height H=2~3m.

[0029] Furthermore, in step S3, the grouting pressure is 0.23-0.28 MPa, preferably 0.25 MPa; the stop grouting pressure is in the range of 0.7-0.8 MPa, preferably 0.75 MPa.

[0030] Furthermore, a C20 concrete cushion layer 5 is poured at the bottom of the energy dissipation well, and the thickness of the cushion layer 5 is 45 to 55 cm, generally 50 cm.

[0031] The new method for reconstructing a flood discharge system in a tailings pond according to the present invention has the following positive effects after adopting the above technical solution:

[0032] (1) The present invention transforms the original drainage culvert through a steel blade angle caisson, performs grouting construction through grouting holes in the grouting area to improve the foundation stability, and further improves the foundation stability through a pile foundation. After the steel blade angle caisson sinks to the top of the original drainage culvert, the steel blade angle caisson structure is optimized into an energy dissipation well, and then a ring-shaped pedestal and a new flood discharge well are constructed to achieve the purpose of flood discharge system management, effectively shorten the construction period, and improve economic benefits while ensuring the safety and reliability of the flood discharge system.

[0033] (2) The present invention utilizes the rheological properties of the tailings in the reservoir and sinks the steel blade angle caisson by its own weight, thereby establishing a construction space for the reconstruction of the drainage culvert in the steel blade angle caisson, which has the advantages of strong operability and reliable construction.

[0034] (3) The present invention utilizes caisson reconstruction on the basis of the original drainage culvert, which can effectively shorten the construction period and reduce the construction cost. It can not only meet the requirements of normal tailings discharge in the tailings pond, but also ensure the needs of flood discharge during heavy rainfall seasons, and has good economic benefits.

[0035] (4) Compared with the single foundation of the traditional flood discharge well, the present invention improves the foundation stability through the pile foundation, annular foundation and other structures, and is safer and more reliable.

[0036] (5) Industrial test studies have shown that the method of the present invention can effectively control floods in the reservoir catchment area and quickly discharge them out of the reservoir, prevent dam breach accidents caused by floods, and ensure the safe operation of the tailings pond.

[0037] (6) The method of the present invention reduces the construction cost by 30% to 40% compared with building a new flood drainage system, and the construction efficiency is more than 45% faster, with significant application effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A cross-sectional view of a new method for reconstructing a flood discharge system in a tailings pond in use according to the present invention;

[0039] Figure 2 The present invention is a top view of a new method for reconstructing a flood drainage system in a used tailings pond.

[0040] Figure numerals: 1-steel blade angle caisson; 2-angle steel; 3-1-grouting area; 3-2-grouting hole; 4-energy dissipation well; 5-cushion; 6-pile foundation; 7-annular cap; 8-new flood discharge well; 9-original drainage culvert. DETAILED DESCRIPTION

[0041] To further describe the present invention, a new method for reconstructing a flood discharge system in a tailings pond according to the present invention is described in further detail below in conjunction with the accompanying drawings.

[0042] Depend on Figure 1The cross-sectional view of a new method for reconstructing a flood discharge system in a tailings pond according to the present invention is shown in combination with Figure 2 It can be seen that the flood drainage system reconstructed by the method of the present invention is composed of a steel blade-angle caisson 1, an energy dissipation well 4, a pile foundation 6, an annular pedestal 7, and a new flood drainage well 8. A cushion layer 5 is also provided at the lower part of the foundation pit of the energy dissipation well 4.

[0043] In the embodiment, a certain ore dressing plant found that the wellbore of the tailings pond drainage well was tilted according to monitoring, which posed a serious safety hazard. In combination with the actual situation of the enterprise's production and the water collection in the tailings pond, a new method of reconstructing the drainage system in the tailings pond in the present invention is adopted to achieve the purpose of eliminating the hidden dangers of the drainage system. The specific implementation steps are as follows:

[0044] Step 1: Steel blade caisson 1 sinks to the bottom under its own weight

[0045] First, fill the connecting road and the construction platform in the reservoir through earthwork operations. After the filling and measurement and layout of the connecting road and the construction platform are completed, the steel blade angle caisson 1 is sunk by its own weight to seal the bottom. In the embodiment, the inner diameter of the steel blade angle caisson 1 is 3m, and the blade foot of the steel blade angle caisson 1 is welded with a ∠200mm*200mm*10mm angle steel 2 to increase the sand breaking capacity of the sinking. The self-weight sinking and bottom sealing process can be coordinated with the control of the sinking speed by mechanically evenly digging sand. The steel blade angle caisson 1 sinks to within 2m of the pipe top elevation of the original drainage culvert. The original drainage culvert 9 is explored by the sounding method at the center and on both sides. After the steel blade angle caisson 1 sinks to the designed elevation and the settlement is stable, C35 concrete is used for bottom sealing. It is required that the strength of the bottom sealing concrete before the next construction is not less than 75% of the design strength.

[0046] Step 2: Drilling and grouting in the grouting area

[0047] Grouting construction is carried out through the grouting hole 3-2 in the grouting area 3-1. Regional parameters such as grouting depth and grouting range are determined according to actual conditions. The grouting depth in the embodiment is 5.7m, the outer diameter of the grouting area 3-1 is 10m, and the grouting holes 3-2 are arranged in two layers in the plane circumferential direction in the grouting area 3-1. The grouting holes 3-2 have an annular layer spacing of 1.5m. Inclined grouting is used from the outside to the inside, with an inclination angle of 60º, a grouting pressure of 0.25MPa, and a stop grouting pressure of 0.75MPa. The orifice is closed and the upward-type hole blocking grouting from bottom to top is adopted. Grouting should start from low pressure and a large injection volume to the final pressure and a small injection volume, and the final grouting pressure should not be less than the design pressure. It is required that the permeability coefficient of the grouting body is not less than 1 Lu Rong after the grouting is completed, and the strength of the grouting body is not less than 2MPa.

[0048] Step 3: Construction of energy dissipation well 4

[0049] The energy dissipation well 4 is excavated in layers from the bottom of the steel blade angle caisson 1. The excavation size is a circular section with a diameter of 3.0m. The excavation is carried out in layers with a layer height of 0.5m. During the excavation of the foundation pit, reinforced concrete is used to cast a retaining wall with a thickness of 0.25m and a height of 0.5m. After the retaining wall is cast, a circular foundation pit section with a net section diameter of 1.5m is formed. A C20 concrete cushion layer 5 is cast at the bottom of the energy dissipation well 4 with a thickness of 50cm. The original drainage culvert 9 within the excavation range of the foundation pit needs to be cut. The upstream of the original drainage culvert 9 is along the foundation pit wall, and 0.75m is left in the foundation pit downstream. The original drainage culvert 9 concrete is manually chiseled, and the steel bars are retained and overlapped with the steel bars of the energy dissipation well 4.

[0050] Step 4: Pile foundation 6 construction

[0051] The pile foundation 6 is arranged on the filled construction platform and symmetrically around the energy dissipation well 4 and on both sides of the original drainage culvert 9. The pile foundation 6 adopts C40 bored cast-in-place piles with a pile body diameter of 600mm and an outer diameter of the pile area of ​​6.5m. The pile length is L and must enter the bearing layer of the foundation below.

[0052] Step 5: Construction of annular platform 7

[0053] The annular cap 7 is constructed on the filled construction platform, using C35 reinforced concrete structure, with a clearance diameter of D1 = 1.0m, an outer diameter of D2 = 8.6m, and a height of 2.5m. Before tying the steel bars, the floating slurry part of the pile head of the pile foundation 6 is chiseled out, and the pile body and its main reinforcement are buried in the annular cap 7. The concrete pouring of the annular cap 7 is completed in one time, and the concrete is preferably poured into the groove by the flat paving method. After the strength of the concrete after pouring is not less than 70% of the design value, the upper new flood discharge well 8 is constructed.

[0054] Step 6: Construction of new flood discharge well 8

[0055] The new drainage well 8 is constructed on the annular pedestal 7. The well body of the new drainage well 8 is a C35 reinforced concrete structure with an inner diameter of 2.0m, a wall thickness of 0.3m, and an outer diameter of 2.6m. The well body structural parameters must meet the flood prevention and drainage requirements.

[0056] The calculation results after the method of the present invention was applied to the tailings pond in use at the ore dressing plant showed that, compared with building a new flood drainage system, the construction cost of rebuilding the flood drainage system using the method of the present invention was reduced by 38.5%, the construction efficiency was increased by 51.0%, and it was safe and reliable, and it withstood the test of the rainy season, achieving unexpected technical effects.

[0057] It should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. in the present invention are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred parts or elements must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A new method for reconstructing a flood discharge system in a tailings pond, characterized in that The reconstructed flood drainage system is composed of a steel blade angle caisson (1), a stilling well (4), a pile foundation (6), an annular cap (7), and a new flood drainage well (8); the stilling well (4) is dug in layers in the steel blade angle caisson (1), and a reinforced concrete wall is cast to form a net circular section; the pile foundation (6) is arranged in a circular ring outside the steel blade angle caisson (1); the annular cap (7) is cast and supported on the pile foundation (6); the new flood drainage well (8) is constructed and supported on the annular cap (7), and the following steps are adopted for implementation: S1 Construction preparation First, according to the location of the damaged tailings pond's flood discharge well and the original drainage culvert buried location, determine the location where the flood discharge system needs to be rebuilt; fill the pond with earthwork to build the connecting road and construction platform to the location where the flood discharge system needs to be rebuilt; S2 Steel blade caisson sinks under its own weight After the filling and surveying and setting out of the connecting road and the construction platform are completed, the steel blade angle caisson (1) is sunk by its own weight to seal the bottom; the angle steel (2) is welded at the blade foot of the steel blade angle caisson (1), and the steel blade angle caisson (1) is sunk to a range of 2m above the top elevation of the original drainage culvert (9). The location of the original drainage culvert (9) is explored by the method of probing at the center and both sides. After the steel blade angle caisson (1) sinks to the designed elevation and the settlement is stable, concrete is used to seal the bottom, and the strength of the bottom sealing concrete is required to be not less than 75% of the designed strength before the next construction; S3 Grouting area drilling grouting The grouting holes (3-2) are arranged in layers along the outer periphery of the steel blade angle caisson (1), and inclined grouting is sequentially adopted from the outside to the inside to form a grouting area (3-1). The grouting holes (3-2) adopt hole-opening closure and upward-type hole-blocking grouting from bottom to top. After the grouting is completed, the permeability coefficient of the grouting body is not less than 1 Lv Rong, and the strength of the grouting body is not less than 2 MPa. S4 Energy Dissipation Well Construction The energy dissipation well (4) is excavated in layers from the bottom of the steel blade angle caisson (1), and a protective wall is cast with reinforced concrete to form a circular foundation pit section; the original drainage culvert (9) is cut within the excavation range of the foundation pit, and the concrete at the overlap between the original drainage culvert (9) and the energy dissipation well (4) is manually chiseled off, and the steel bars are retained, and the original drainage culvert (9) is overlapped with the steel bars at the bottom of the energy dissipation well (4), and then cast with concrete to seal it; S5 Pile foundation construction Arranging pile foundations (6) in the filled construction platform, wherein the pile foundations (6) are symmetrically arranged around the energy dissipation well (4) and on both sides of the original drainage culvert (9), and the pile foundations (6) must enter the underlying foundation bearing layer; S6 Ring Cap Construction The annular cap (7) is constructed on a well-filled construction platform. The annular cap (7) adopts a reinforced concrete structure. Before tying the steel bars, the floating slurry part of the pile head of the pile foundation (6) is chiseled out first, and the pile body and its main reinforcement are buried inside the annular cap (7). The concrete of the annular cap (7) is poured once, and the concrete is poured into the groove by a flat paving method. After the strength of the concrete is not less than 70% of the design value after pouring, the upper new flood discharge well (8) is constructed; S7 New flood drainage well construction The new flood discharge well (8) is constructed on the annular pedestal (7). The well body of the new flood discharge well (8) is a reinforced concrete structure. The inner diameter R of the new flood discharge well (8) is calculated according to the "Design Code for Tailings Facilities" (GB 50863-2013). The well body structural parameters must meet the flood prevention and drainage requirements.

2. A new method for reconstructing a flood discharge system in a tailings pond as claimed in claim 1, characterized in that The steel blade angle caisson (1) is a C35 reinforced concrete structure; the inner diameter of the steel blade angle caisson (1) is 1.5~2.0R, the wall thickness δ is 0.35~0.5m, and the height is 3.0~5.5m; the blade angle of the steel blade angle caisson (1) is welded with an angle steel, and the angle steel size is ∠ (200~500) mm* (200~500) mm* (9~12) mm.

3. A new method for reconstructing a flood discharge system in a tailings pond as claimed in claim 1, characterized in that : With the common central axis of the steel blade angle caisson (1), the energy dissipation well (4) and the new flood discharge well (8) as the radius, the grouting area (3-1) ranges from Dr = 4 to 6R, the grouting holes (3-2) have a hole diameter of φ = 90 to 130 mm, and are arranged in layers along the annular plane, with 2 to 3 layers and a layer spacing of φ d =1.5m~2.5m, grouting depth h=5m~10m, grouting is inclined from outside to inside, and the inclination angle is 55º~65º.

4. A new method for reconstructing a flood discharge system in a tailings pond as claimed in claim 1, characterized in that The energy dissipation well (4) is excavated in layers in the steel blade angle caisson (1), with a layered excavation height of 0.5m~1.0m, and a retaining wall is cast using C25 reinforced concrete, with a thickness of 0.2m~0.3m and a height of 0.5m~1.0m. After the retaining wall is cast, a circular section with a net cross-section diameter of 1.0m~2.0m is formed.

5. A new method for reconstructing a flood discharge system in a used tailings pond as claimed in claim 1, characterized in that The pile foundation (6) is a C40 bored pile with a pile body diameter in the range of 500-700 mm, a pile area diameter of 2R-4R, and a pile length of L=10-20 m.

6. A new method for reconstructing a flood discharge system in a used tailings pond as claimed in claim 1, characterized in that The annular support (7) is a C35 reinforced concrete structure, with an inner diameter D1 being the same as the diameter of the energy dissipation well (4), an outer diameter D2 = 3~5R, and a height H = 2~3m.

7. A new method for reconstructing a flood discharge system in a used tailings pond as claimed in claim 1, characterized in that The new flood discharge well (8) is a C35 reinforced concrete structure with an inner diameter of 1.8 to 2.3 m and a wall thickness of 0.27 to 0.34 m.

8. A new method for reconstructing a flood discharge system in a used tailings pond as claimed in claim 1, characterized in that : In step S3, the grouting pressure is 0.23~0.28MPa, and the stop grouting pressure is 0.7~0.8MPa.

9. A new method for reconstructing a flood discharge system in a used tailings pond as claimed in claim 1, characterized in that A C20 concrete cushion layer (5) is poured at the bottom of the energy dissipation well (4), and the cushion layer (5) has a thickness of 45 to 55 cm.

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