Surface mine tailing sand mechanical stoping construction method

Abstract

The invention provides a surface mine tailing sand mechanical stoping construction method which comprises the following steps: S1, evaluating the stability of an original tailing pile, and determining the stoping necessity of the original tailing pile according to an evaluation result; s2, one side of the raw tailing heap is divided into three areas, and reverse uncovering propulsion is conducted on the three areas along the same elevation; s3, excavating and propelling from one area in the middle of the three areas to areas on the two sides, and stacking the stoped ore sand to a designated position to form a new reservoir area; s4, stacking is conducted on the periphery of the new tailing pile area to form a box dam, and a buffer layer and an impermeable layer are constructed on the outer side synchronously along with the stacking progress of the box dam; s5, after the box dam of the new tailing pile is stacked to the specified height, anchor rods are constructed on the buffer layer and the impermeable layer; and S6, ore sand is gradually stacked from outside to inside with the box dam as a stacking platform till original tailing pile recovery is completed, and a new tailing pile is stacked.

Description

Technical Field

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

[0002] Tailings sand is the waste material after the ore is processed and valuable minerals are removed. It usually exists in granular form and is mainly composed of gangue minerals in the ore or target minerals with low content. Tailings sand recovery can achieve resource reuse, reduce pollution, increase economic income, reduce the risk of tailings dam failure, provide strong support for the sustainable development of mining areas, and is a key way to green development of mines. However, the storage of new tailings may cause environmental problems such as soil and water pollution and geological disasters.

[0003] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

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

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

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

[0007] Step S1, conducting geological survey on the original tailings pile, evaluating the stability of the original tailings pile, and determining the necessity of mining the original tailings pile according to the evaluation results;

[0008] Step S2, dividing one side of the original tailings pile into three areas, and advancing the three areas along the same elevation to expose the top surface of the ore sand inside the original tailings pile;

[0009] Step S3, excavating from an area in the middle of the three areas to the areas on both sides, and stacking the mined ore sand at a designated location to form a new storage area;

[0010] Step S4, as the new tailings pile is piled, a dam is formed by piling around the new tailings pile area, and a buffer layer and an impermeable layer are constructed on the outside in sync with the progress of the dam pile;

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

[0012] Step S6, using the surrounding dam as a stacking platform, gradually stacking the ore sand from the outside to the inside until the original tailings pile is mined and stacked into a new tailings pile.

[0013] Preferably, in step S4, as the construction of the buffer layer progresses, a first impermeable membrane is gradually constructed inside the impermeable layer; a second impermeable membrane is laid above the new tailings pile, and a plain soil layer is provided above the second impermeable membrane, and a drainage ditch is provided on the plain 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, stability is evaluated based on the stacking morphology, particle size composition and water content of the raw ore pile.

[0016] Preferably, step S6, by measuring and setting out, the boundary, construction position and mining depth of the original tailings pile mining area are determined, and when mining reaches the muddy bottom plate at the bottom of the original tailings pile, stripping material or block stone replacement method is used for mining excavation.

[0017] Preferably, a buffer slope is provided on the outer side of the buffer layer, and the anti-seepage layer is arranged on the buffer slope;

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

[0019] Preferably, after the reservoir area of ​​the new tailings pile is leveled, a third impermeable membrane is laid first, and then a clay protective layer is laid on top of the third impermeable membrane, and then the new tailings pond is stacked.

[0020] Beneficial effects: During the mining process, the ore sand is piled into a dam, and the dam is used as a platform for gradual stacking from the outside to the inside. As the transportation machinery stacks the ore sand, the new tailings pile is compacted. In addition, a buffer layer and an impermeable layer are set outside the tailings pile to carry out impermeable treatment of the new tailings pile, thereby preventing groundwater from seeping out of the tailings pile, thereby ensuring the environmental quality to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present 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. Among them:

[0022] Figure 1 A schematic diagram of the recovery process in a specific embodiment provided by the present invention;

[0023] Figure 2 A schematic structural diagram of a new tailings pile in a specific embodiment provided by the present invention;

[0024] Figure 3 This is a simplified structural diagram of the seepage well in the specific embodiment provided by the present invention.

[0025] In the figure: 1. tailings pile; 2. seepage well; 3. buffer layer; 4. anti-seepage layer; 5. first anti-seepage membrane; 6. anchor rod; 7. anti-seepage bottom; 8. sealing membrane; 9. second anti-seepage membrane; 10. bare soil layer; 11. collecting tank; 12. filter cover; 13. supporting mechanism; 14. stabilizing frame; 15. seepage pipe; 16. sealing cover; 17. ventilation pipe; 18. suction pipe; 19. suction pump; 20. drainage ditch; 21. gravel. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0027] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, they can be fixedly connected or detachably connected; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0029] like Figure 1-3 As shown, a construction method for mechanical recovery of tailings sand in an open-pit mine includes the following steps: Step S1, conducting a geological survey on the original tailings pile 1, evaluating the stability of the original tailings pile 1, and formulating corresponding safety protection measures according to the stability of the original tailings pond. For example, the presence of a large number of cracks and fracture surfaces, and the presence of large pieces of broken rock in some areas indicate that the tailings sand may have experienced settlement and stress changes after accumulation, resulting in reduced stability in the local area and potential risks of slip or collapse. The necessity of recovering the original tailings pile 1 is determined according to the evaluation results, and the recovery route is determined based on the evaluation results.

[0030] Step S2, divide one side of the original tailings pile 1 into three areas to ensure the isolation between the operating area and the non-operating area, avoid disturbing the unmined area, and reversely advance 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, excavation is carried out from an area in the middle of the three areas to the areas on both sides. After the tailings sand is exposed, the tailings sand step is divided into three sections for mining, and the recovered ore is piled at a designated location to form a new tailings pile 1.

[0032] Step S4, as the new tailings pile 1 is piled up, a dam is formed by piling up the tailings pile 1 outside the new tailings pile 1 area. A small amount of tailings sand will inevitably overflow during transportation, which can easily cause environmental pollution and dust pollution. Therefore, it should not be transported too far, nor should it be discarded around roads and mining sites. As the dam is piled up, a buffer layer 3 and an impermeable layer 4 are constructed on the outside simultaneously, wherein the buffer layer 3 is formed by piling up clay, and the impermeable layer 4 is formed by compacting the clay.

[0033] Step S5, after the surrounding dam of the new tailings pile 1 is piled to a specified height, anchor rods 6 are constructed on the buffer layer 3 and the impermeable layer 4, and the protective capacity of the buffer layer 3 and the impermeable layer 4 is ensured by reinforcing the anchor rods 6 to prevent the new tailings pile 1 from sliding outward.

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

[0035] In an optional embodiment, in step S4, as the construction of the buffer layer progresses, a first impermeable membrane 5 is gradually constructed inside the impermeable layer 4. The first impermeable membrane 5 can be provided with multiple layers, and the multiple layers of the first impermeable membrane 5 are distributed in the impermeable layer 4 at a certain interval. The first impermeable membrane 5 can prevent the new tailings pond from seeping in the horizontal direction and avoid water pollution. Furthermore, in order to reduce the groundwater content of the new tailings pile 1 in the rainy season, a second impermeable membrane 9 is laid above the new tailings pile 1, and 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 preset closed clean water pool to discharge the water to a designated location after treatment. Grouting holes are provided on the outer wall of the anchor rod 6, and grouting is used to consolidate the plurality of anchor rods 6 with the corresponding buffer layer 3 or impermeable layer 4. To ensure the stability of the anti-seepage layer 4, an anchor net is connected to the upper end of the anchor rod 6, which improves the consolidation capacity between the anchor rods 6. Furthermore, an anti-seepage slope is provided on the outside of the anti-seepage layer 4, and turf is laid on the anti-seepage slope to avoid mudslides. The anti-seepage layer 4 and the buffer layer 3 are both made of clay soil.

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

[0037] The third impermeable membrane and the closing membrane 8 are fixed by hot melt, and the first impermeable membrane 5, the third impermeable membrane, the second impermeable membrane 9 and the closing membrane 8 are all made of impermeable materials such as HDPE membrane and polyethylene membrane. In step S6, as the new tailings pile 1 is stacked, a plurality of seepage wells 2 are evenly drilled on the new tailings pile 1, and the depth of the seepage well 2 is adapted to the stacking height of the new tailings pile 1; a seepage pipe 15 is provided in the seepage well 2, and gravel 21 is filled between the seepage well 2 and the seepage pipe 15, and a suction pipe 18 is provided in the seepage pipe 15; the feed end of the suction pump 19 is connected to the suction pipe 18, and the discharge end of the suction pump 19 extends to the drainage ditch 20. A stabilizing frame 14 corresponding to the second impermeable membrane 9 is provided in the middle of the seepage pipe 15. The stabilizing frame 14 includes an outer frame, a hoop and spokes. The outer frame may be circular. The hoop is provided to fix the second impermeable membrane 9 to the outer wall of the seepage pipe 15 by hooping. The open end of the hoop is fixed by bolts, and the outer wall of the seepage pipe 15 can be tightly clamped by the bolts. The outer frame and the hoop are concentrically distributed, and a plurality of spokes uniformly distributed about the circumference thereof are detachably provided between the outer frame and the hoop. The spokes may be square steel or square wood, and the spokes are fixed to the outer frame and the hoop by bolts.

[0038] A uniformly distributed seepage port is provided at the middle and lower part of the outer wall of the seepage pipe 15, and the seepage port can collect the seepage water inside the new tailings pile 1 and then enter the seepage pipe 15, and the seepage water is filtered by the seepage port. The lower end of the suction pipe 18 extends into the pipe mouth of the seepage pipe 15, and the upper end of the suction pipe 18 extends out of the seepage pipe 15 and is connected to the suction pump 19. The sealing cover 16 is arranged at the upper end of the seepage pipe 15, and a first perforation corresponding to the suction pipe 18 is provided on the sealing cover 16, and a corresponding ventilation pipe 17 is also provided on the sealing cover The second through hole, the upper end of the ventilation pipe 17 is bent in an inverted U shape, the sealing cover 16 is fixed to the flange at the upper end of the seepage pipe 15 by circumferentially evenly distributed bolts, a conical rubber plug is provided below the sealing cover 16, the smaller end of the rubber plug extends into the upper end of the seepage pipe 15, and a first channel and a second channel corresponding to the first through hole and the second through hole are provided in the middle of the rubber plug, so that as the sealing cover 16 squeezes the rubber plug, it deforms radially to squeeze the suction pipe 18 and the ventilation pipe 17 respectively, and fixes the two by friction.

[0039] A plurality of support mechanisms 13 uniformly distributed in the longitudinal direction are provided on the outside of the seepage pipe 15. 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 outside of the seepage pipe 15. The length of the support column is adapted to the diameter difference between the outer wall of the seepage pipe 15 and the inner wall of the seepage well 2. The end 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 optional embodiment, a conical liquid collecting trough 11 is provided at the bottom of the seepage well 2, and the liquid collecting trough 11 collects the seepage liquid. A filter plate corresponding to the gravel 21 is provided above the liquid collecting trough 11, and a seepage pipe 15 extends into the liquid collecting trough 11. A filter cover 12 located in the liquid collecting trough 11 is provided at the lower end of the suction pipe 18, thereby ensuring that the seepage water can be effectively sucked out through collection.

[0041] In an optional embodiment, in step S1, the stability of the original ore pile is evaluated by its stacking morphology, particle size composition, and moisture content. Specifically, exploratory excavation can be carried out to determine the stability of the original ore pile by discovering the layered structure of the tailings sand, different particles and color characteristics between the layers, weathering phenomena, etc.

[0042] In an optional embodiment, step S6, by measuring and setting out, the boundary, construction position and mining depth of the original tailings pile 1 mining area are determined. During the tailings sand mining process, the tailings sand mining boundary, the final slope and the specific position of the transportation road are measured and calibrated to avoid over-excavation, under-excavation or mis-excavation and control the construction accuracy.

[0043] When mining reaches the muddy bottom plate at the bottom of the original tailings pile 1, the stripping material or block stone replacement method is used for mining excavation, and the replacement depth is 1.0m.

[0044] In an optional embodiment, a buffer slope is provided on the outer side of the buffer layer 3 to facilitate the accumulation of the anti-seepage layer 4. The anti-seepage layer 4 is arranged on the buffer slope. In order to further increase the anti-seepage capacity, an anti-seepage bottom 7 is provided at the bottom of the anti-seepage layer 4 with an elevation below the elevation of the new tailings pile 1 or the bottom of the buffer layer 3, and the anti-seepage bottom 7 extends horizontally to below the buffer layer 3.

[0045] In this embodiment, the anti-seepage bottom 7 is formed by compacting clay, and the anti-seepage bottom 7 extends horizontally to below the buffer layer 3, and a closed film 8 is laid below the anti-seepage bottom 7, and the closed film 8 is fixed to the first anti-seepage membrane 5. Specifically, the bottom of the first anti-seepage membrane 5 extends to the lower edge of the anti-seepage bottom 7 and is horizontally bent toward one side of the buffer layer 3. The closed film 8 is fixed to the horizontal bend below the first anti-seepage membrane 5.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A mechanical recovery method for tailings sand in an open-pit mine, characterized in that: The following steps are involved: Step S1, conducting geological survey on the original tailings pile, evaluating the stability of the original tailings pile, and determining the necessity of mining the original tailings pile according to the evaluation results; Step S2, dividing one side of the original tailings pile into three areas, and advancing the three areas along the same elevation to expose the top surface of the ore sand inside the original tailings pile; Step S3, excavating from an area in the middle of the three areas to the areas on both sides, and stacking the mined ore sand at a designated location to form a new storage area; Step S4, as the new tailings pile is piled, a dam is formed by piling around the new tailings pile area, and a buffer layer and an impermeable layer are constructed on the outside in sync with the progress of the dam pile; Step S5, after the surrounding dam of the new tailings pile is piled to a specified height, anchor rods are constructed on the buffer layer and the impermeable layer; Step S6, using the surrounding dam as a stacking platform, gradually stacking the ore sand from the outside to the inside until the original tailings pile is mined and stacked into a new tailings pile.

2. The open-pit mine tailings sand mechanical recovery construction method according to claim 1 is characterized in that: In step S4, as the construction of the buffer layer progresses, a first impermeable membrane is gradually constructed inside the impermeable layer; a second impermeable membrane is laid above the new tailings pile, and a plain soil layer is provided above the second impermeable membrane, and a drainage ditch is provided on the plain soil layer; The anchor rod is consolidated with the corresponding buffer layer or impermeable layer through the anchor rod grouting.

3. The open-pit mine tailings sand mechanical recovery construction method according to claim 1 is characterized in that: In step S1, the stability of the raw ore pile is evaluated based on its stacking morphology, particle size composition and water content.

4. The open-pit mine tailings sand mechanical recovery construction method according to claim 1 is characterized in that: Step S6, determining the boundary, construction position and mining depth of the original tailings pile mining area by measuring and setting out, and when mining reaches the muddy bottom plate at the bottom of the original tailings pile, adopting the method of stripping material or block stone replacement to carry out mining excavation.

5. The open-pit mine tailings sand mechanical recovery construction method according to claim 2 is characterized in that: A buffer slope is provided on the outer side of the buffer layer, and the anti-seepage layer is arranged on the buffer slope; The bottom of the anti-seepage layer is provided with an anti-seepage bottom whose elevation is below the elevation of the new tailings pile or the bottom of the buffer layer, and the anti-seepage bottom extends to below the buffer layer in the horizontal direction.

6. The open-pit mine tailings sand mechanical recovery construction method according to claim 1 is characterized in that: After the reservoir area of ​​the new tailings pile is leveled, a third 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 stacked.

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