Construction method of open-pit mine tailings sand mechanical mining

Abstract

The application provides a construction method for open-pit mine tailings mechanical mining, comprising the following steps: step S1, evaluating the stability of the original tailings heap, and determining the necessity of the original tailings heap mining according to the evaluation result; step S2, dividing one side of the original tailings heap into three regions, and performing reverse stripping and advancing on the three regions along the same elevation; step S3, excavating and advancing from the middle region of the three regions to the regions on both sides, and stacking the mined sand to a designated position to form a new storage area; step S4, stacking a dam outside the new tailings heap region, and simultaneously constructing a buffer layer and an impermeable layer on the outside with the stacking progress of the dam; step S5, after the dam of the new tailings heap is stacked to a designated height, constructing an anchor rod on the buffer layer and the impermeable layer; and step S6, gradually stacking the sand from the outside to the inside on the dam as a stacking platform until the original tailings heap is mined and stacked as a new tailings heap.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tailings recovery, and particularly relates to a construction method for mechanical recovery of tailings sand in an open-pit mine. BACKGROUND

[0002] Tailings sand is a waste material after valuable minerals are removed from ore after beneficiation treatment, and usually exists in the form of particles, mainly composed of gangue minerals or low-content target minerals in the ore. Tailings sand recovery can realize resource recycling, reduce pollution, increase economic income, reduce the risk of tailings dam collapse, and provide strong support for the sustainable development of the mining area, and is a key way for green development of the mine, but the new tailings stacking process may cause environmental problems such as soil and water pollution and geological disasters.

[0003] Therefore, it is necessary to provide an improved technical solution for the above-mentioned deficiencies of the prior art. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art, and the present application provides a construction method for mechanical recovery of tailings sand in an open-pit mine.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solution:

[0006] A construction method for mechanical recovery of tailings sand in an open-pit mine, comprising the following steps:

[0007] Step S1, geological survey is performed on the original tailings pile, the stability of the original tailings pile is evaluated, and the necessity of recovery of the original tailings pile is determined according to the evaluation result;

[0008] Step S2, one side of the original tailings pile is divided into three regions, and the three regions are pushed back along the same elevation to expose the top surface of the tailings sand inside the original tailings pile;

[0009] Step S3, the middle region of the three regions is excavated and pushed to the regions on both sides, and the recovered tailings sand is stacked in a designated position to form a new reservoir area;

[0010] Step S4, as the new tailings pile is stacked, a dam is formed by stacking outside the new tailings pile area, and a buffer layer and a impermeable layer are constructed on the outside as the dam is stacked;

[0011] Step S5, after the dam of the new tailings pile is stacked to a specified height, anchor rods are constructed on the buffer layer and the impermeable layer;

[0012] Step S6, the tailings sand is gradually stacked from the outside to the inside on the dam as a stacking platform, until the recovery of the original tailings pile is completed and the new tailings pile is formed.

[0013] Preferably, in step S4, the first impermeable membrane is gradually constructed inside the buffer layer as the buffer layer construction progresses; the second impermeable membrane is laid on the new tailings pile, and a soil layer is arranged above the second impermeable membrane, and a drainage ditch is arranged on the soil layer;

[0014] The anchor rod is consolidated with the corresponding buffer layer or impermeable layer through the anchor rod grouting.

[0015] Preferably, in step S1, the stability is evaluated by the stacking form, particle size composition, and water content of the raw ore pile.

[0016] Preferably, in step S6, the boundary, construction position, and mining depth of the raw tailings pile mining area are determined by measuring the line, and when the mining reaches the sludge-like floor at the bottom of the raw tailings pile, the stripping material or block stone backfill method is used for mining and excavation.

[0017] Preferably, the buffer layer is provided with a buffer slope on the outside, and the impermeable layer is arranged on the buffer slope.

[0018] The bottom of the impermeable layer is provided with an impermeable bottom with an elevation below the bottom elevation of the new tailings pile or the buffer layer, and the impermeable bottom extends to below the buffer layer in the horizontal direction.

[0019] Preferably, after the new tailings pile is leveled in the reservoir area, a third impermeable membrane is laid first, then a clay protection layer is laid on the third impermeable membrane, and then the new tailings pile is stacked.

[0020] Beneficial effects: In the mining process, the ore sand is stacked as a dam, and the new tailings pile is compacted and compacted during the stacking process of the transportation machinery. In addition, the buffer layer and the impermeable layer are arranged outside the tailings pile, which can prevent the new tailings pile from seepage, and avoid the seepage of underground water in the tailings pile, thereby maximizing the environmental quality. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation of the application. Among them:

[0022] Fig. 1 The mining process schematic diagram in the specific embodiment provided by the present application;

[0023] Fig. 2 The structure diagram of the new tailings pile in the specific embodiment provided by the present application;

[0024] Fig. 3 The structure diagram of the seepage well in the specific embodiment provided by the present application.

[0025] In the diagram: 1. Tailings pile; 2. Seepage well; 3. Buffer layer; 4. Impermeable layer; 5. First impermeable membrane; 6. Anchor bolt; 7. Impermeable bottom; 8. Sealing membrane; 9. Second impermeable membrane; 10. Plain soil layer; 11. Collection tank; 12. Filter cover; 13. Support mechanism; 14. Stabilizer; 15. Seepage pipe; 16. Sealing cover; 17. Ventilation pipe; 18. Suction pipe; 19. Suction pump; 20. Drainage ditch; 21. Crushed stone. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0027] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0029] like Figs. 1-3 As shown, a mechanical mining method for tailings in an open-pit mine includes the following steps: Step S1, conduct geological surveys on the original tailings pile 1, assess the stability of the original tailings pile 1, and formulate corresponding safety protection measures based on the stability of the original tailings pile. For example, if there are many cracks and fracture surfaces, and large pieces of broken rock appear in some areas, it indicates that the tailings may have undergone settlement and stress changes after accumulation, resulting in reduced stability in local areas and potential risks of sliding or collapse. Based on the assessment results, determine the necessity of mining the original tailings pile 1, and determine the mining route based on the assessment results.

[0030] Step S2: Divide one side of the original tailings pile 1 into three areas to ensure the isolation between the working area and the non-working area and avoid disturbing the unmined area. Proceed with the back-opening of the three areas along the same elevation to expose the top surface of the ore sand inside the original tailings pile 1.

[0031] Step S3, the tailings sand is excavated and pushed from one of the three regions to the two regions, and after the tailings sand is exposed, the tailings sand steps are divided into three sections for mining, and the mined sand is stacked in a designated position to form a new tailings pile 1.

[0032] Step S4, as the new tailings pile 1 is stacked, a dam is formed by stacking outside the periphery of the new tailings pile 1, and a small amount of tailings sand inevitably spills during transportation, which can cause environmental pollution and dust pollution, so it is not suitable to transport too far or to be discarded around the road and the mining area; as the dam is stacked, the buffer layer 3 and the impermeable layer 4 are constructed on the outside simultaneously, wherein the buffer layer 3 is formed by stacking viscous soil, and the impermeable layer 4 is formed by ramming viscous soil.

[0033] Step S5, after the dam of the new tailings pile 1 is stacked to a designated height, anchor rods 6 are constructed on the buffer layer 3 and the impermeable layer 4, which reinforce and ensure the protection capability of the buffer layer 3 and the impermeable layer 4, avoiding the new tailings pile 1 from sliding outward.

[0034] Step S6, the mine sand is gradually stacked from the outside to the inside on the dam as a stacking platform until the original tailings pile 1 is mined and stacked as the new tailings pile 1.

[0035] In an optional embodiment, in step S4, as the buffer layer is constructed, a first impermeable membrane 5 is gradually constructed inside the impermeable layer 4, the first impermeable membrane 5 can be provided in multiple layers, and the multiple layers of the first impermeable membrane 5 are distributed in the impermeable layer 4 at a certain interval, which can avoid horizontal seepage of the new tailings pile 1 and water pollution, and further, in order to reduce the groundwater content of the new tailings pile 1 in the rainy season, a second impermeable membrane 9 is laid on the new tailings pile 1, a soil layer 10 is provided above the second impermeable membrane 9, a drainage ditch 20 is provided on the soil layer 10, and the drainage ditch 20 extends to a closed clean water pool, the water is treated and discharged to a designated position, the anchor rod 6 is provided with a grouting hole on the outer wall, and the multiple anchor rods 6 are consolidated with the corresponding buffer layer 3 or impermeable layer 4 through grouting. In order to ensure the stability of the impermeable layer 4, the upper end of the anchor rod 6 is correspondingly connected with an anchor net, which improves the consolidation ability between the anchor rods 6, and further, a seepage prevention slope is provided on the outside of the impermeable layer 4, and a turf is laid on the seepage prevention slope to avoid mudslides, and the impermeable layer 4 and the buffer layer 3 are both formed by stacking viscous soil.

[0036] In this embodiment, after the reservoir area of the new tailings pile 1 is leveled, a third impermeable membrane is laid first, then a clay protection layer is laid on the third impermeable membrane, and then the new tailings pile is stacked.

[0037] The third impermeable membrane and the sealing membrane 8 are fixed by hot melting. The first impermeable membrane 5, the third impermeable membrane, the second impermeable membrane 9 and the sealing membrane 8 are all made of HDPE membrane, polyethylene membrane or other impermeable materials. In step S6, as the new tailing pile 1 is stacked, a plurality of seepage wells 2 are evenly arranged on the new tailing pile 1, and the depth of the seepage well 2 is matched with the stacking height of the new tailing pile 1. A seepage pipe 15 is arranged in the seepage well 2, and gravel 21 is filled between the seepage well 2 and the seepage pipe 15. A suction pipe 18 is arranged in the seepage pipe 15. The suction pump 19 is connected to the suction pipe 18 through the inlet end, and the outlet end of the suction pump 19 extends to the drainage ditch 20. The middle part of the seepage pipe 15 is provided with a stabilizing frame 14 corresponding to the second impermeable membrane 9. The stabilizing frame 14 includes an outer frame, a hoop and spokes. The outer frame can be circular. The hoop is arranged to fix the second impermeable membrane 9 on the outer wall of the seepage pipe 15 by clamping. The open end of the hoop is fixed by bolts, and the hoop can be driven by the bolts to tightly hold the outer wall of the seepage pipe 15. The outer frame and the hoop are concentrically distributed. A plurality of spokes are arranged between the outer frame and the hoop in a detachable manner and are uniformly distributed around the circumference.

[0038] A plurality of seepage openings are evenly arranged on the lower middle part of the outer wall of the seepage pipe 15. The seepage openings can collect the seepage water in the new tailing pile 1 and then enter the seepage pipe 15. The seepage openings filter the seepage water. The lower end of the suction pipe 18 extends into the pipe opening of the seepage pipe 15. The upper end of the suction pipe 18 extends out of the seepage pipe 15 and is connected to the suction pump 19. A sealing cover 16 is arranged on the upper end of the seepage pipe 15. A first perforation corresponding to the suction pipe 18 is arranged on the sealing cover 16. A second perforation corresponding to the air exchange pipe 17 is also arranged on the sealing cover 16. The upper end of the air exchange pipe 17 is bent in an inverted U shape. The sealing cover 16 is fixed to the flange on the upper end of the seepage pipe 15 by bolts uniformly distributed around the circumference. A tapered rubber plug is arranged below the sealing cover 16. The smaller end of the rubber plug extends into the upper end of the seepage pipe 15. A first channel and a second channel corresponding to the first perforation and the second perforation, respectively, are arranged in the middle part of the rubber plug. The sealing cover 16 extrudes the rubber plug in the radial direction to extrude the suction pipe 18 and the air exchange pipe 17, respectively, so as to fix them by friction.

[0039] A plurality of support mechanisms 13 are arranged on the outer part of the seepage pipe 15 and are uniformly distributed along the longitudinal direction. The support mechanisms 13 are used to support the seepage pipe 15 to avoid the influence of sedimentation on the seepage pipe 15. The support mechanism 13 includes a support sleeve and a support column. The support sleeve is sleeved on the outer part of the seepage pipe 15. The length of the support column is matched with the radial difference between the outer wall of the seepage pipe 15 and the inner wall of the seepage well 2. The end part of the support column is provided with an arc-shaped support plate corresponding to the inner wall of the seepage well 2.

[0040] In an alternative embodiment, the seepage well 2 is provided with a conical collecting tank 11 at the bottom, which collects the seepage liquid. The collecting tank 11 is provided with a filter plate corresponding to the gravel 21. The seepage pipe 15 extends into the collecting tank 11. The lower end of the suction pipe 18 is provided with a filter cover 12 located in the collecting tank 11, so that the seepage water can be effectively pumped by collection.

[0041] In an alternative embodiment, in step S1, the stability of the raw ore heap is evaluated by the stacking form, particle size composition, and water content of the raw ore heap. Specifically, a trial excavation can be performed to determine the stability of the raw ore heap by discovering the layered structure of the tailings sand, the different particle and color characteristics between the layers, weathering phenomena, etc.

[0042] In an alternative embodiment, in step S6, the boundaries, construction positions, and mining depth of the raw tailings heap 1 are determined by measurement and marking. During the tailings sand mining process, the specific positions of the tailings sand mining boundaries, the final slope, and the transportation road are measured and marked to avoid over-excavation, under-excavation, or mis-excavation, and to control the construction accuracy.

[0043] When the mining reaches the bottom of the raw tailings heap 1, which is a sludge-like bottom plate, a stripping material or block stone backfill method is used for mining and excavation, and the backfill depth is 1.0 m.

[0044] In an alternative embodiment, the outer side of the buffer layer 3 is provided with a buffer slope, which facilitates the accumulation of the impermeable layer 4. The impermeable layer 4 is arranged on the buffer slope. To further increase the impermeability, the impermeable layer 4 is provided with an impermeable bottom 7, which is located below the bottom of the new tailings heap 1 or the buffer layer 3, and extends horizontally to below the buffer layer 3.

[0045] In this embodiment, the impermeable bottom 7 is formed by compacting clay, and extends horizontally to below the buffer layer 3. A sealing membrane 8 is arranged below the impermeable bottom 7, and is fixed to the first impermeable membrane 5. Specifically, the bottom of the first impermeable membrane 5 extends to the lower edge of the impermeable bottom 7, and is bent horizontally to one side of the buffer layer 3. The sealing membrane 8 is fixed to the horizontal bend below the first impermeable membrane 5.

[0046] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application is within the scope of the claims of the present application.

Claims

1. A method for mechanically mining tailings sand in open-pit mines, characterized in that, Includes the following steps: Step S1: Conduct a geological survey of the original tailings pile, assess the stability of the original tailings pile, and determine the necessity of remining the original tailings pile based on the assessment results. Step S2: Divide one side of the original tailings pile into three areas, and push the three areas back along the same elevation to expose the top surface of the ore sand inside the original tailings pile. Step S3: Excavation proceeds from the middle area of ​​the three areas to the areas on both sides, and the mined ore is piled up in the designated location to form a new storage area. Step S4: As the new tailings pile is built, a dam is formed by building around the new tailings pile area, and a buffer layer and an anti-seepage layer are constructed on the outer side in sync with the progress of building the dam. As the construction of the buffer layer progresses, the first geomembrane is gradually constructed inside the geomembrane; a second geomembrane is laid above the new tailings pile, and a plain soil layer is provided above the second geomembrane, with drainage ditches provided on the plain soil layer. The buffer layer is provided with a buffer slope on its outer side, and the seepage-proof layer is provided on the buffer slope; The bottom of the seepage-proof layer is provided with a seepage-proof bottom that is located below the bottom elevation of the new tailings pile or the buffer layer, and the seepage-proof bottom extends horizontally to below the buffer layer; Step S5: After the new tailings pile is stacked to the designated height, anchor bolts are installed on the buffer layer and the seepage prevention layer. The anchor bolts are then grouted to solidify them with the corresponding buffer layer or seepage prevention layer. Step S6: Using the dam as a stacking platform, gradually stack the ore from the outside to the inside until the original tailings pile is mined and stacked as a new tailings pile. As the new tailings pile is laid, multiple seepage wells are evenly drilled on the new tailings pile, with the depth of the seepage wells matching the height of the new tailings pile. Seepage pipes are installed in the seepage wells, and the space between the seepage wells and seepage pipes is filled with crushed stone. Suction pipes are installed in the seepage pipes. The feed end of the suction pump is connected to the suction pipe, and the discharge end of the suction pump extends to the drainage ditch. The middle of the seepage pipe is equipped with a stabilizing frame corresponding to the second geomembrane. The stabilizing frame includes an outer frame, a hoop, and spokes. The outer frame is circular. The hoop fixes the second geomembrane to the outer wall of the seepage pipe by clamping. The open end of the hoop is fixed by bolts and is driven to grip the outer wall of the seepage pipe by bolts. The outer frame and the hoop are concentrically distributed. Multiple spokes are detachably provided between the outer frame and the hoop, which are evenly distributed around its circumference.

2. The method for mechanical mining of tailings in open-pit mines according to claim 1, characterized in that, In step S1, stability is assessed by examining the packing morphology, particle size distribution, and moisture content of the raw ore pile.

3. The method for mechanical mining of tailings in open-pit mines according to claim 1, characterized in that, Step S6: Determine the boundary, construction location, and mining depth of the original tailings heap mining area by measuring and setting out. When mining to the bottom of the original tailings heap, which is a silt-like bottom plate, use stripping material or boulders to replace the material for mining excavation.

4. The method for mechanical mining of tailings in open-pit mines according to claim 1, characterized in that, After leveling the area of ​​the new tailings pond, a third layer of impermeable membrane is laid first, and then a clay protective layer is laid on top of the third impermeable membrane before the new tailings pond is built.

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