Method for damming tailings pond through midline method

Abstract

The invention discloses a midline method tailing pond damming method. The method comprises the steps that a seepage drainage mattress layer and an initial dam are piled up; tailings are discharged at the upstream of the initial dam for bottom layer ore accumulation, and meanwhile a waste rock slope protection layer and a waste rock blocking dam layer are formed on the seepage drainage mattress layer and the initial dam in a heaping mode through a center line method; and the waste rock slope protection layer and the waste rock blocking dam layer are piled up layer by layer on the current dam body through a center line method. According to the midline method tailing pond damming method, firstly, the barren rock slope protection layer is formed through barren rock heaping, then, the barren rock blocking dam layer is formed through barren rock heaping, finally, tailings are directly discharged on the inner side of the barren rock blocking dam layer for deposition to form the tailing deposition layer, and the barren rock slope protection area is used for supporting the barren rock blocking dam area at the bottom and conducting seepage drainage. The waste rock blocking dam area is used for stacking discharged tailings at the dam top of the current dam, damming can be carried out through the midline method without adopting a cyclone, and the problem that construction is complex in the midline method damming process through an existing cyclone is solved.

Description

Technical Field

[0001] The invention relates to the technical field of tailings treatment, in particular to a centerline tailings pond damming method. Background Art

[0002] A tailings pond refers to a place constructed by building a dam to block the valley mouth or enclosing land for storing tailings or other industrial waste. It usually includes an initial dam, an accumulation dam, a flood discharge system, drainage facilities, monitoring facilities and auxiliary facilities. A tailings pond is an important part of mining production facilities.

[0003] In the existing technology, the methods of tailings damming are divided into upstream method, center line method, downstream method or one-time damming method. In recent years, due to the development of technology and policy encouragement, the number of cases of domestic mines using the center line method to build dams has increased. In comparison, the upstream method has a low permeability coefficient of the tailings dam, a high position of the infiltration line, and poor stability of the dam body; both the center line method and the downstream method require the use of cyclones for damming, which is complex, and there are problems with the movement and management of the cyclones, as well as the stability of the temporary slope and dust.

[0004] In view of this, it is necessary to provide a new center-line tailings dam construction method to achieve dam construction without using a cyclone, while also solving the problem of severe soil erosion and dust pollution on the downstream slope of the center-line method. Summary of the invention

[0005] The center-line tailings pond damming method provided by the present invention solves the technical problem that the existing center-line tailings pond damming method needs to use a cyclone for damming, which has complex construction.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for building a tailings dam using a centerline method, wherein the tailings dam comprises a drainage cushion layer, an initial dam on the drainage cushion layer, a tailings area upstream of the initial dam, and a waste rock stacking area at the dam top and downstream of the initial dam, wherein the waste rock stacking area comprises a waste rock slope protection area and a waste rock retaining dam area, wherein the waste rock slope protection area is located at the bottom of the initial dam and on the drainage cushion layer, and the waste rock retaining dam area is located on the initial dam and the waste rock slope protection area, and the method comprises the following steps: S1, stacking the drainage cushion layer and the initial dam, and placing the initial dam on the drainage cushion layer; S2, discharging tailings upstream of the initial dam to stack the bottom ore, and at the same time , using the center line method to pile up the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer on the drainage cushion layer and the initial dam, after the top elevation of the bottom ore accumulation reaches the first preset elevation, and the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer are piled up, enter step S3; S3, using the center line method to pile up layer by layer on the current dam body, forming waste rock slope protection layer and waste rock retaining dam layer layer by layer, all waste rock retaining dam layers are combined to form a waste rock slope protection area, all waste rock retaining dam layers are combined to form a waste rock retaining dam area, and the waste rock slope protection layer and waste rock retaining dam layer are respectively formed by waste rock piling;

[0008] Specifically include:

[0009] S31, discharge tailings on the inner side of the current waste rock retaining dam layer; at the same time, S32, use waste rock to pile up the next waste rock slope protection layer at the bottom of the slope of the current dam body, and the layer height of the waste rock slope protection layer is not less than the preset layer height; S33, use waste rock to pile up the next waste rock retaining dam layer on the waste rock slope protection layer and the current dam body using the center line method, and the layer height of the waste rock retaining dam layer is the preset layer height; S34, when the layer height of the tailings deposition layer formed by the accumulation of discharged tailings in the current layer reaches the preset tailings layer height, and the construction of the next waste rock retaining dam layer is completed, it is determined that the next dam construction layer is completed; repeat steps S31 and S34 to pile up the waste rock slope protection area and the waste rock retaining dam area, and pile up to form the tailings area.

[0010] Furthermore, the waste rock retaining dam layer is formed by compacting waste rock.

[0011] Furthermore, the waste rock slope protection area is formed by direct waste rock paving.

[0012] Furthermore, the downstream slope protection surface of the waste rock dumping area is a multi-level slope surface.

[0013] Furthermore, based on the target plan for annual tailings discharge of the target mine, combined with the tailings dam height-storage capacity curve, the annual accumulation height of the waste rock storage area is obtained, and the annual expected number of tailings height increase periods is determined based on the annual accumulation height and the preset tailings layer height, wherein the number of layers of the annual waste rock retaining dam corresponds to the annual expected number of tailings height increase periods.

[0014] Furthermore, the expected volume of waste rock that can be provided by the target spoil dump during the current raising period is obtained, and the target paving demand volume corresponding to the current raising period is obtained according to the design plan. If the expected volume of waste rock is not greater than the target paving demand volume, then according to the design plan, stacking is carried out with the goal of filling the bottom of the waste rock slope protection layer corresponding to the current raising period; if the annual expected volume of waste rock is greater than the target paving volume, then stacking is carried out according to the design plan and the surplus is stacked to the adjacent next layer of waste rock slope protection layer.

[0015] Furthermore, if the cross-section of the valley is parabolic, the initial dam volume is calculated using the formula: (b+0.8mH1); if the cross-section of the valley is simplified to a trapezoid, the initial dam volume is (b+mKH1); where V is the initial dam body engineering volume, L is the upper width of the valley cross section, l is the lower bottom width of the valley cross section, b is the initial dam top width, m is the average value of the inner and outer dam slope coefficients, and K is the preset coefficient.

[0016] The present invention has the following beneficial effects:

[0017] The center-line tailings pond dam construction method provided by the present invention makes full use of the waste rocks abandoned during the construction of the mine site. When each phase of tailings is piled up, based on the drainage cushion layer, the waste rocks are first piled up to form a waste rock slope protection layer, and then the waste rock retaining dam layer is formed by the waste rocks. Finally, the tailings are directly discharged on the inner side of the waste rock retaining dam layer for deposition to form a tailings deposition layer, i.e., a tailings accumulation body (the tailings are discharged on the inner side of the waste rock retaining dam layer), and finally the waste rock slope protection area, the waste rock retaining dam area and the tailings area are piled up; the waste rock slope protection area is located at the bottom of the slope of the current dam body. Located on the drainage cushion layer, the waste rock slope protection area is used to support the waste rock retaining dam area at the bottom and carry out drainage, and the waste rock retaining dam area is located on the initial dam and the waste rock slope protection area to support and pile up the discharged tailings on the dam top of the current dam. The center line method of dam construction can be realized without the use of cyclones, which solves the technical problem of complex construction in the existing center line method of dam construction using cyclones; at the same time, it solves the technical problem of insufficient capacity of the mine spoil dump; at the same time, the tailings pond has a stable structure and does not require gravel piling, which also solves the problem of serious soil erosion and dust pollution on the downstream slope of the center line method.

[0018] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the construction principle of the existing upstream tailings dam;

[0021] Figure 2 This is a schematic diagram of the construction principle of the existing downstream tailings dam;

[0022] Figure 3 This is a schematic diagram of the construction principle of the existing center-line tailings dam;

[0023] Figure 4 is a flow chart of a centerline tailings damming method in one embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of the structure of a tailings pond in one embodiment of the present invention;

[0025] Figure 6 This is one of the schematic diagrams of the layered stacking principle of the tailings pond in one embodiment of the present invention;

[0026] Figure 7 This is the second schematic diagram of the layered stacking principle of the tailings pond in one embodiment of the present invention. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0028] Please refer to Figure 1 Through research, it is found that when the tailings deposit beach in the reservoir rises to the top of the initial dam, sand is excavated on the dry beach, and a sub-dam is built upstream parallel to the axis of the initial dam to form a new ore discharge space. The ore discharge pipe is moved to the top of the sub-dam to continue ore discharge and filling. When the tailings deposit beach rises to the top of the sub-dam, the next level of sub-dam is built. In this way, the accumulation dam gradually advances upstream according to a certain slope gradient until the final accumulation elevation. In the upstream tailings damming method, the initial dam is equivalent to the drainage prism of the accumulation dam. The dam body slope of the later dam is composed of multiple sub-dams, without an obvious upstream dam surface contour line, and the position of the sub-dam continues to move upstream as production advances. The inner beach of the sub-dam is formed by the natural deposition of tailings particles in the flowing slurry. The sedimentary beach often contains more fine mud interlayers, which reduces its permeability coefficient and strength, the infiltration line is at a higher position, and the dam body stability is poor. However, it has the advantages of simple dam construction process, convenient management, and low cost.

[0029] Please refer to Figure 2Through research, it is found that after the tailings pond is put into operation, the tailings are graded by a hydrocyclone at the top of the initial dam, and the bottom flow sedimentation gradually increases and moves downstream at a certain slope ratio, first gradually forming an upstream slope, and then forming a final downstream slope when the final accumulation elevation is reached. The overflow is discharged into the reservoir and deposited naturally. When the dam top reaches a certain height, the ore discharge pipe and grading equipment are moved to the new dam top to continue the graded dam construction. The dam top gradually rises and moves downstream until the final accumulation elevation. The construction characteristics of the downstream late dam are that it has a clear dam body contour line and the dam top is constantly shifted downstream. This type of accumulation dam uses a large amount of cyclone bottom flow sedimentation to build an accumulation dam. The dam body is compacted by coarse tailings, which completely improves the basic conditions of the supporting prism. It has good permeability and high shear strength, so the dam body has good stability, but this dam construction method requires a narrow and long dam site terrain and the separation of enough coarse tailings as a prerequisite. During the dam construction process, it is required to strictly control the height difference between the dam crest and the sedimentation beach in the reservoir to maintain a balanced rise to meet the requirements of flood control in the reservoir and dam stability. The cyclone equipment is difficult to move, the dam construction workload is large, the loss is also large, and the production management and maintenance are relatively complicated.

[0030] Please refer to Figure 3 Through research, it is found that the centerline dam construction process is similar to the downstream tailings dam construction process, but the top of the accumulation dam is always centered on the initial dam axis (i.e., the dam axis). The dam body is built with coarse tailings downstream of the median vertical line, and the sedimentation beach formed by the remaining overflow tailings upstream. When the centerline method is used to raise the dam body, the accumulation slope continues to move downstream, and the final accumulation slope is formed when the final accumulation elevation is reached. The overflow of the cyclone is discharged into the upstream of the top line of the accumulation dam. This accumulation dam improves the basic conditions of the supporting prism of the tailings pond. The supporting prism is basically formed by the accumulation of coarse tailings from the bottom flow of the cyclone, and the infiltration line is also reduced, which is beneficial to the stability of the accumulation dam. However, the use of cyclones to build dams brings a lot of troubles to production, such as the movement and management of cyclones, the stability of temporary slopes, and dust. Its advantages and disadvantages are between the upstream and downstream types. The main disadvantages are that the equipment is difficult to move, the management is inconvenient, the stability of the temporary slope is insufficient, it is easy to form soil erosion when it rains, and it is easy to form dust when it is dry.

[0031] At present, the common pollution control measures for the mid-line tailings pond mainly include: for dust control, adding pseudo-dust agents to the tailings or spraying or fog cannons to reduce dust in large areas during the later production process. For soil erosion, drainage ditches are built on the slopes or outside the tailings accumulation area, slopes are fixed with vegetation, or the slope outside the tailings accumulation is filled with ponds, drainage mattresses are set at the bottom of the coarse sand area, or other drainage measures are taken.

[0032] like Figure 4 , Figure 5 , Figure 6 as well as Figure 7As shown, the present invention provides a centerline tailings dam construction method, the tailings dam includes a drainage cushion layer, an initial dam on the drainage cushion layer, a tailings area upstream (inside) of the initial dam, and a waste rock stacking area (waste rock masonry area) at the dam top and downstream (outside) of the initial dam, the waste rock stacking area includes a waste rock slope protection area (direct discharge dam construction area) and a waste rock retaining dam area (rolling dam construction area), the waste rock slope protection area is at the bottom of the slope of the initial dam and on the drainage cushion layer, the waste rock retaining dam area is on the initial dam and the waste rock slope protection area, including the steps: S1, stacking the drainage cushion layer and the initial dam, and making the initial dam on the drainage cushion layer ; S2, discharge tailings upstream of the initial dam to pile up the bottom mine, and at the same time, use the center line method to pile up the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer on the drainage cushion layer and the initial dam, and enter step S3 after the top elevation of the bottom mine accumulation reaches the first preset elevation and the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer are completed; S3, use the center line method to pile up layer by layer on the current dam body, and form waste rock slope protection layer and waste rock retaining dam layer layer by layer. All waste rock retaining dam layers are combined to form a waste rock slope protection area, and all waste rock retaining dam layers are combined to form a waste rock retaining dam area. The waste rock slope protection layer and waste rock retaining dam layer are respectively formed by waste rock piling;

[0033] Specifically, it includes: S31, discharging tailings on the inner side of the current waste rock retaining dam layer; at the same time, S32, using waste rocks to pile up at the bottom of the slope of the current dam body to form the next waste rock slope protection layer, and the layer height of the waste rock slope protection layer is not less than the preset layer height; S33, using waste rocks to pile up on the waste rock slope protection layer and the current dam body using the center line method to form the next waste rock retaining dam layer, and the layer height of the waste rock retaining dam layer is the preset layer height; S34, when the layer height of the tailings deposition layer formed by the accumulation of discharged tailings in the current layer reaches the preset tailings layer height, and the construction of the next waste rock retaining dam layer is completed, it is determined that the next dam construction layer is completed; repeat steps S31 and S34 to pile up to form a waste rock slope protection area and a waste rock retaining dam area, and accumulate to form the tailings area.

[0034] It can be understood that the initial dam can be built with waste rock from the mine dump or other materials; when the top elevation of the tailings pile is close to the top of the initial dam, the top elevation of the bottom mine pile is determined to reach the first preset elevation. In the specific construction, the drainage cushion layer is first constructed, and then the initial dam is constructed on the drainage cushion layer. When the tailings are discharged and accumulated, the first phase of the waste rock slope protection layer and the first phase of the waste rock retaining dam layer are constructed on the initial dam and the drainage cushion layer.

[0035] Furthermore, the waste rock retaining dam layer is formed by compacting waste rock.

[0036] Furthermore, the waste rock slope protection area is formed by direct waste rock paving.

[0037] Furthermore, the downstream slope protection surface of the waste rock dumping area is a multi-level slope surface.

[0038] Optionally, in a specific embodiment of the present invention, the waste rock slope protection area is located on the drainage cushion layer and downstream of the initial dam, and the waste rock retaining dam area is arranged on the periphery of the waste rock slope protection area to cover the waste rock slope protection area.

[0039] It can be understood that the preset layer height is determined by the tailings deposition layer deposited in each period. In the present invention, the tailings deposition layer needs to be piled up layer by layer. Before each tailings deposition layer is piled up, the corresponding waste rock retaining dam layer and waste rock slope protection layer need to be piled up on the current dam body. In order to ensure the rationality of the force, the waste rock slope protection layer is piled up and then the waste rock retaining dam layer is piled up on the waste rock slope protection layer and the current dam body. Generally, when the current tailings deposition layer is piled up, the waste rock slope protection layer and waste rock retaining dam layer of the next layer are piled up simultaneously, so as to facilitate the rapid accumulation of the next tailings deposition layer.

[0040] Optionally, the stacking method of the waste rock slope protection layer is determined according to the amount of waste rock. If the amount of waste rock is large (exceeding the required amount of the next layer of waste rock slope protection layer), it is possible to pile up multiple layers of waste rock slope protection layers and then pile up a layer of waste rock retaining dam layer on the waste rock slope protection layer, that is, during the construction process, a layer of waste rock retaining dam layer is supported by multiple layers of waste rock slope protection layers. If the amount of waste rock just meets the required amount of the current waste rock slope protection layer, the design height of the waste rock slope protection layer is the preset height. At this time, a layer of waste rock retaining dam layer is supported by a layer of waste rock slope protection layer.

[0041] For details, please refer again to Figure 6 According to the design plan, it is assumed that the required volume of the waste rock slope protection layer in the M-1 period is X M-1 , assuming that the required volume of the waste rock slope protection layer in the Mth period is X M The expected volume of waste rock in the target mine during the time corresponding to the waste rock slope protection layer of the M-1 period is Y M-1 The expected volume of waste rock in the target mine during the time corresponding to the waste rock slope protection layer in the Mth period is Y M , if Y M-1 ≥X M-1 +X M-1 ; In the M-1th phase, the M-1th phase waste rock slope protection layer and the M-1th phase waste rock slope protection layer are built at the same time, and then the M-1th phase waste rock retaining dam layer is built on the M-1th phase waste rock slope protection layer. At this time, one layer of waste rock retaining dam layer is supported by two layers of waste rock slope protection layers; if Y M-1 <X M-1 According to the design plan, the priority is to fill the bottom foundation of the M-1 phase waste rock slope protection layer, and then raise the pile after filling the bottom foundation.

[0042] Furthermore, in order to rationally utilize waste rock and ensure the structural stability and permeability of the tailings pond, the waste rock retaining dam layer is formed by paving and stacking rolled waste rock; the waste rock slope protection area is formed by paving directly discharged waste rock.

[0043] Preferably, different compaction standards are adopted for the waste rock slope protection layer and the waste rock retaining dam layer. The compaction strength of the waste rock slope protection layer is greater than that of the waste rock retaining dam layer, which further improves the construction efficiency on the basis of ensuring the stability and rationality of the structure.

[0044] Furthermore, the downstream slope protection surface of the waste rock pile area is a multi-level slope surface. It can be understood that in the present invention, if the waste rock volume is large and the slope gradient is increased, if the waste rock volume is small, the slope gradient is reduced, while meeting the requirements of the design slope (slope ratio) in the design scheme.

[0045] Furthermore, based on the target plan for annual tailings discharge of the target mine, combined with the tailings dam height-storage capacity curve, the annual accumulation height of the waste rock storage area is obtained, and the annual expected number of tailings height increase periods is determined based on the annual accumulation height and the preset tailings layer height, wherein the number of layers of the annual waste rock retaining dam corresponds to the annual expected number of tailings height increase periods.

[0046] Furthermore, if the cross-section of the valley is parabolic, the initial dam volume is calculated using the formula: (b+0.8mH1); if the cross-section of the valley is simplified to a trapezoid, the initial dam volume is (b+mKH1); where V is the initial dam body engineering volume, L is the upper width of the valley cross section, l is the lower bottom width of the valley cross section, b is the initial dam top width, m is the average value of the inner and outer dam slope coefficients, and K is the preset coefficient.

[0047] The value of k is shown in Table 1.

[0048] Table 1

[0049] l / L 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 K 0.67 0.73 0.78 0.82 0.86 0.89 0.92 0.94 0.96 0.98 1.00

[0050] The present invention provides a specific centerline tailings dam construction method, which specifically includes:

[0051] Step 1: Building a drainage cushion layer and an initial dam, and placing the initial dam on the drainage cushion layer, wherein waste rock is used to build the initial dam;

[0052] Step 2: At the initial stage of ore discharge, tailings are directly discharged on the inner side (upstream) of the initial dam, and the first level of waste rock dam is built on the initial dam top and its outer side (downstream). When the top elevation of the accumulated tailings is lower than the initial dam top, when the top elevation of the accumulated tailings is close to the initial dam top, the first stage of tailings deposition layer is completed;

[0053] Specifically, it includes: using direct discharge of waste rock to pile up the first-stage waste rock slope protection layer at the bottom of the downstream of the initial dam, using the center line method and rolling waste rock to pile up the first-stage waste rock retaining dam layer on the first-stage waste rock slope protection layer and the initial dam, and depositing the first-stage tailings deposition layer inside the first-stage waste rock retaining dam layer;

[0054] Step 3: Start the second-stage waste rock damming on the current dam body (the initial dam and the existing waste rock damming combined dam body on the initial dam) and deposit the second-stage tailings deposition layer, specifically including: using direct-discharged waste rock to pile up the second-stage waste rock slope protection layer at the bottom of the current dam body, using the center line method and rolling waste rock to pile up the second-stage waste rock retaining dam layer on the second-stage waste rock slope protection layer and the current dam body, and depositing the second-stage tailings deposition layer on the inner side of the second-stage waste rock retaining dam layer;

[0055] Repeat step 3 until the Mth level of waste rock damming is completed and the Mth period of tailings sedimentation layer is deposited, where M is a positive integer, M is less than N, and N is the total number of periods;

[0056] Step 4: Start to build the M+1th level of waste rock dam on the current dam body and deposit the M+1th tailings deposition layer, specifically including: use rolled waste rock to pile the M+1th waste rock retaining dam layer at the bottom of the current dam body, the M+1th waste rock retaining dam layer covers the Nth waste rock slope protection layer, the M+1th waste rock retaining dam layer extends from the bottom to the top of the current dam body, and deposits the M+1th tailings deposition layer on the inner side of the M+1th waste rock retaining dam layer;

[0057] Repeat step 4 until the final designed tailings accumulation elevation (designed number of sedimentation layers) is reached.

[0058] In the present invention, in order to make the waste rock slope protection layer built by adopting direct discharge of waste rock have a certain supporting capacity, N is not less than 1 / 2 of the designed deposition layers of tailings.

[0059] The center-line tailings pond dam construction method provided by the present invention does not require cyclone equipment, thus omitting the operation and maintenance costs of the cyclone; it accommodates waste rock from a spoil dump or a mining site (for dam construction), thus solving the problem of insufficient capacity of a mine spoil dump; and for mining enterprises whose tailings particle size is generally fine, it can solve the problem of insufficient coarse sand and difficulty in balancing the amount of sand; even for tailings with coarse particle size, the stability of the waste rock dam body relative to the dam body built with coarse tailings will be enhanced; the problem of soil erosion on the downstream slope of the center-line tailings pond is avoided; the waste rock stacking area is divided into zones, and different rolling standards are adopted, thus reducing the construction cost while ensuring the stability of the dam body.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for building a tailings dam using a centerline method, characterized in that: The tailings pond comprises a drainage cushion layer, an initial dam on the drainage cushion layer, a tailings area upstream of the initial dam, and a waste rock pile area at the dam top and downstream of the initial dam, wherein the waste rock pile area comprises a waste rock slope protection area and a waste rock retaining dam area, wherein the waste rock slope protection area is located at the bottom of the slope of the initial dam and on the drainage cushion layer, and the waste rock retaining dam area is located on the initial dam and the waste rock slope protection area, and comprises the following steps: S1, build the drainage cushion layer and the initial dam, and make the initial dam on the drainage cushion layer; S2, discharge tailings upstream of the initial dam to pile up the bottom ore, and at the same time, use the center line method to pile up the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer on the drainage cushion layer and the initial dam, and enter step S3 after the top elevation of the bottom ore accumulation reaches the first preset elevation and the first phase of waste rock slope protection layer and the first phase of waste rock retaining dam layer are completed; S3, using the center line method to pile up layer by layer on the current dam body, forming a waste rock slope protection layer and a waste rock retaining dam layer layer by layer, all the waste rock retaining dam layers are combined to form a waste rock slope protection area, all the waste rock retaining dam layers are combined to form a waste rock retaining dam area, and the waste rock slope protection layer and the waste rock retaining dam layer are respectively formed by waste rock piling; Specifically include: S31, discharge tailings inside the waste rock retaining dam layer of the current layer; at the same time, S32, using waste rocks to pile up at the bottom of the slope of the current dam body to form a next layer of waste rock slope protection layer, wherein the layer height of the waste rock slope protection layer is not less than a preset layer height; S33, using waste rock to pile up on the waste rock slope protection layer and the current dam body by the center line method to form a next layer of waste rock retaining dam layer, wherein the layer height of the waste rock retaining dam layer is a preset layer height; S34, when the height of the tailings deposition layer formed by the accumulation of discharged tailings in the current layer reaches a preset tailings layer height, and the construction of the waste rock retaining dam layer of the next layer is completed, determining that the construction of the next layer of the dam is completed; Repeat steps S31 and S34 to form a waste rock slope protection area and a waste rock retaining dam area, and then accumulate to form the tailings area.

2. The method for building a tailings dam using the centerline method according to claim 1, characterized in that: The waste rock retaining dam layer is formed by compacting waste rocks.

3. The method for building a tailings dam using the centerline method according to claim 1, characterized in that: The waste rock slope protection area is formed by directly discharging waste rocks.

4. The method for building a tailings dam using the centerline method according to claim 1, characterized in that: The downstream slope protection surface of the waste rock dumping area is a multi-level slope surface.

5. The method for building a tailings dam using the centerline method according to claim 3, characterized in that: According to the target mine's annual tailings discharge target plan, combined with the tailings dam height-storage capacity curve, the annual accumulation height of the waste rock dump area is obtained. Based on the annual accumulation height and the preset tailings layer height, the annual expected number of tailings height increase periods is determined, wherein the number of annually constructed waste rock retaining dam layers corresponds to the annual expected number of tailings height increase periods.

6. The method for building a tailings dam using the centerline method according to any one of claims 1 to 5, characterized in that: Obtain the expected volume of waste rock that can be provided during the current heightening period of the target dump. According to the design plan, obtain the target laying demand volume corresponding to the current heightening period, If the expected volume of waste rock is not greater than the target paving demand, the waste rock slope protection layer corresponding to the current heightening period will be piled up according to the design plan; If the expected annual volume of waste rock is greater than the target paving volume, it will be piled up according to the design plan and the surplus will be piled into the adjacent next layer of waste rock slope protection.

7. The method for building a tailings dam using the centerline method according to any one of claims 1 to 5, characterized in that: If the cross-section of the valley is parabolic, the initial dam volume is calculated using the formula Obtain; where V is the initial dam body engineering volume, L is the upper width of the valley cross section, l is the lower bottom width of the valley cross section, b is the initial dam top width, m is the average value of the inner and outer dam slope coefficients, and K is the preset coefficient.

8. The method for building a tailings dam using the centerline method according to any one of claims 1 to 5, characterized in that: If the cross-section of the valley is simplified to a trapezoid, the initial dam volume is calculated using the formula Obtain; where V is the initial dam body engineering volume, L is the upper width of the valley cross section, l is the lower bottom width of the valley cross section, b is the initial dam top width, m is the average value of the inner and outer dam slope coefficients, and K is the preset coefficient.

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