Three-dimensional storage method suitable for strip mine pit water

Abstract

The invention discloses a three-dimensional storage method suitable for strip mine pit water, and belongs to the technical field of strip mining water resource protection, and the three-dimensional storage method comprises the following steps: carrying out regional geology and hydrogeology survey of a strip mine area, and obtaining regional landform and hydrogeology parameters of the strip mine area; determining the water inflow and water quality characteristics of the open pit, and establishing a pit water inflow dynamic monitoring system and a data collection mechanism; a three-dimensional storage system of strip mine pit water is planned, the stored water quality standard and the storable water amount of the three-dimensional storage system are determined in combination with the mine pit water inflow, and construction is conducted according to the process requirements of the three-dimensional storage system; and determining a water utilization path and a water utilization principle of the strip mine area, and carrying out dynamic water storage and water utilization by utilizing the three-dimensional storage system according to an operation plan of the strip mine pit so as to finish three-dimensional storage and resource utilization of water resources of the strip mine area. Water resources of the strip mine pit can be effectively managed and utilized, the utilization rate of the water resources is increased, and underground water resources are protected and restored.

Description

Technical Field

[0001] The invention relates to the technical field of open-pit mining water resource protection, and in particular to a three-dimensional storage method suitable for open-pit mine water. Background Art

[0002] Open-pit coal mining generally produces a large amount of mine water, which often causes the loss of groundwater resources within the influence area of ​​the mining area, the gradual expansion of the drop funnel area, and the gradual increase in the depth of the water level. At the same time, the mine water needs to be drained away in time to ensure safe production in the mine. Open-pit mines also consume a large amount of production water and ecological water in the normal production process, and the surrounding areas of the mining area also need a large amount of living, agricultural and ecological water. There is a huge contradiction between the inability to efficiently store mine water in open-pit coal mining and the extreme shortage of production water. The existing open-pit coal mine water storage methods mainly include surface water reservoirs, pit bottom water reservoirs, etc. Large-scale surface water reservoirs and pit bottom water reservoirs have a single water storage method, and it is difficult to store for a long time and maintain their resource attributes. Summary of the invention

[0003] Technical problem to be solved: In order to solve the technical problem that water resources cannot be effectively utilized in the open-pit mining process of the prior art, the present invention provides a three-dimensional storage method suitable for open-pit mine water. By comprehensively considering the geological conditions, hydrogeological conditions and environmental protection needs of the mining area, an advanced three-dimensional storage system is established, which can effectively manage and utilize the water resources of the open-pit mine, reduce the negative impact on the environment, improve the recycling efficiency of water resources, and replenish groundwater resources to achieve protection and restoration of groundwater resources.

[0004] Technical solution: The present invention provides a three-dimensional storage method for open-pit mine water, which comprises the following steps: Step 1: Conduct regional geological and hydrogeological surveys of the open-pit mine area to obtain the regional topographic and geomorphic parameters of the open-pit mine area and the hydrogeological parameters of the dump, Quaternary aquifer, and deep bedrock aquifer in the coal seam floor; Step 2: Determine the water inflow and water quality characteristics of the open-pit mine, and establish a dynamic monitoring system and data collection mechanism for the water inflow; Step 3: Plan a three-dimensional storage system for open-pit mine water. The three-dimensional storage system includes five types of storage systems: surface water storage system, pit bottom water storage system, dump reconstruction ecological aquifer water storage system, Quaternary loose aquifer water storage system, and coal seam floor deep bedrock aquifer water storage system. Combined with the water inflow from the open-pit mine, determine the corresponding water quality standards and storable water volume of the five storage systems, and carry out construction according to the process requirements of the three-dimensional storage system; Step 4: Determine the water use channels and principles in the open-pit mine area. According to the operation plan of the open-pit mine, use the surface water storage system, pit bottom water storage system, spoil dump to reconstruct the ecological aquifer water storage system, Quaternary loose aquifer water storage system and coal seam floor deep bedrock aquifer water storage system to dynamically store and use water, and complete the three-dimensional storage and resource utilization of water resources in the open-pit mine area.

[0005] Preferably, the hydrogeological parameters in step 1 include aquifer water level, aquifer permeability, aquifer water storage coefficient, mine water inflow, mine water inflow points, mine mining plan, spoil dump size and spoil dump permeability.

[0006] Preferably, the specific construction steps of the surface water storage system in step 3 are: Step S1: Conduct geological survey on the open-pit mine area to obtain soil type and groundwater level parameters; Step S2: planning several water reservoir locations in the open-pit mine area where the geological structure is stable, the groundwater level is low, and there is no adverse geological body; Step S3: Design the volume, depth and anti-seepage measures of the water reservoir, excavate the water reservoir to form a water reservoir body that meets the design, lay HDPE anti-seepage membrane or concrete lining, and complete the anti-seepage treatment of the pool bottom and pool wall; Step S4: installing a drainage system consisting of a water collection well and drainage pipes, and laying out water diversion pipes for draining rainwater and mine water; configuring a pH sensor and a turbidity meter for the water reservoir to form an automatic water quality monitoring system, and monitoring changes in the water quality of the water reservoir; Step S5: Establish a regular inspection mechanism for the surface water storage system, clean the sediment in the storage tank and inspect the anti-seepage system.

[0007] Preferably, the specific construction steps of the pit bottom water storage system in step 3 are: Step L1: Determine the water accumulation area at the bottom of the open pit and the expected amount of water accumulation, and design the shape and volume of the water reservoir; Step L2: excavate an open pit bottom water reservoir, ensure the stability of the bottom and surrounding rocks of the reservoir, and use grouting technology to reinforce the bottom plate of the reservoir to prevent settlement and leakage; lay HDPE anti-seepage membrane or concrete lining, double-layer waterproof concrete sandwiched with anti-seepage membrane, and complete the construction of the anti-seepage layer; Step L3: Lay out a water circulation system consisting of water diversion pipes and drainage pipes for diverting rainwater and mine water; install a fully automatic water level monitor on the reservoir to track the water level in real time; Step L4: Establish a regular inspection mechanism for the pit water storage system, clean the sediment in the storage tank and inspect the anti-seepage system.

[0008] Preferably, the specific construction steps of the dump site in step 3 to reconstruct the ecological aquifer water storage system are: Step M1: Conduct damage assessment on the thickness, lithology, permeability, strength of the original aquifer and the original aquiclude of the open pit, as well as the scope and degree of damage of the open pit, and obtain the hydrogeological parameters of the original aquifer and the original aquiclude of the open pit through geological exploration, drilling sampling, and indoor testing; Step M2: Establish a relationship curve between the groundwater level depth and vegetation coverage in the open-pit mine area, and design the thickness of the artificially reconstructed aquifer and the depth of the aquiclude according to the relationship curve to maintain ecological water use on the surface of the dump site; Step M3: Utilize clay or bentonite natural materials existing in the mining area in combination with polymer synthetic materials to form a composite waterproof layer material with good construction performance as a reconstructed waterproof layer. The thickness of the reconstructed waterproof layer should be greater than or equal to the thickness of the original waterproof layer and be connected to the original waterproof layer.

[0009] Step M4: Using the Quaternary gravel and rock blocks stripped from the mining area as aquifer materials, using grouting pumps and rollers, and adopting grouting and compaction methods to construct a reconstructed aquifer in the inner dump. The thickness of the reconstructed ecological aquifer in the dump should be less than or equal to the thickness of the original aquifer, and connected to the original aquifer, and ensure that the construction process can effectively fill the voids and cracks in the aquifer; Step M5: construct a phased pile hole press-in type anti-seepage wall or a trench pouring type waterproof wall to prevent the lateral loss of the restored shallow water. When the open-pit mine is closed, the horizontal waterproof layer is constructed; Step M6: Carry out quantitative evaluation of parameters and calculation of recharge water volume under different recharge conditions for the ecological aquifer reconstructed by the spoil dump, use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity and runoff time of groundwater in the ecological aquifer reconstructed by the spoil dump, study the hydrodynamic field and migration and diffusion laws of characteristic components under the recharge conditions of the ecological aquifer reconstructed by the spoil dump, and carry out slope stability, recharge environmental impact assessment and safe mining impact assessment under the recharge conditions of the ecological aquifer reconstructed by the spoil dump.

[0010] Preferably, after the construction of the ecological aquifer reconstruction in the spoil dump is completed, step M4 is to perform grouting in the slope area to form a reinforced slope to ensure the stability of the slope. The width of the grouting reinforcement area is calculated using the empirical formula for the water-bearing or water-conducting fault water-blocking coal pillar: ; In the above formula, L is the width of the grouting reinforcement area / m; K is the safety factor, which is 2~5; M is the thickness of the ecological aquifer reconstructed by the dump / m; p is the actual head value of the ecological aquifer reconstructed by the dump at the maximum water storage capacity / MPa; K p It is the tensile strength of the rock-concrete composite in the grouting reinforcement section / MPa.

[0011] Preferably, the specific construction steps of the Quaternary loose aquifer water storage system in step 3 are: Step N1: Conduct hydrogeological condition exploration and pumping test of the shallow Quaternary aquifer in the coal seam roof of the open-pit mine area to identify the hydrogeological parameters and groundwater runoff characteristics of typical recharge areas; Step N2: Select an area downstream of the open-pit mine in the direction of groundwater runoff and with strong stratum permeability to carry out drainage water recharge, construct several recharge wells in the recharge area as injection wells and observation wells, install groundwater automatic monitoring instruments in the observation wells, test the water level, water temperature and conductivity data of the Quaternary loose aquifer online, and carry out water level and water quality monitoring during the recharge process; among them, there are a total of 7 wells for injection wells and observation wells, well No. 1 is used as an injection well, and the other 6 wells are observation wells, and the 6 observation wells are arranged on the back side of the injection well in the form of vertices and midpoints of the side lines of an equilateral triangle; Step N3: sampling the groundwater of the aquifer during the recharge process of the Quaternary loose aquifer, and testing the suspended matter, organic matter, microorganisms, and special indicator components of mine water in the water sample; Step N4: Carry out quantitative evaluation of parameters under original hydrogeological conditions and different recharge conditions and calculate the recharge water volume. Use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, runoff time and discharge water volume of groundwater in the Quaternary loose aquifer. Study the hydrodynamic field and migration and diffusion laws of characteristic components under the recharge conditions of the Quaternary loose aquifer. Carry out environmental impact assessment and safe exploitation impact assessment of the Quaternary loose aquifer.

[0012] Preferably, the specific construction steps of the deep bedrock aquifer water storage system in the coal seam floor in step 3 are: Step M1: Based on the on-site water pressure test phase and past monitoring and testing data, select a location to construct the ground recharge hole that is convenient for ground water and power supply, close to the reservoir, avoids land acquisition costs, is easy to maintain, and has good permeability in the recharge target layer; Step M2: Carry out quantitative evaluation of parameters under original hydrogeological conditions and different reinjection conditions and calculate reinjection water volume. Use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, runoff time and discharge volume of deep groundwater in the coal seam floor. Study the hydrodynamic field and migration and diffusion laws of characteristic components under reinjection conditions of deep aquifers in the coal seam floor. Carry out environmental impact assessment, water inrush hazard classification and safe mining impact assessment under deep reinjection conditions of the coal seam floor.

[0013] Preferably, the water use in step 4 includes production water in the mining area, ecological water in the mining area, domestic water around the mining area, agricultural water around the mining area, and ecological water around the mining area; the water use principle is to give priority to ensuring production and ecological water in the mining area, and secondly to ensuring domestic water, agricultural water, and ecological water around the mining area.

[0014] Preferably, in step 4, the water storage principle is determined according to the amount of water that can be stored in the mining area, the water use route and the water use principle, and surface reservoirs and pit bottom reservoirs are preferentially used for temporary water storage during drainage and operation in the open-pit mine, and used for production and ecological water in the mining area, as well as living and agricultural water around the mining area; Secondly, in combination with the different hydrogeological conditions in the open-pit mining area, the construction spoil dump is used to reconstruct the ecological aquifer, the Quaternary loose aquifer and the bedrock aquifer deep in the coal seam floor for recharge and water storage; during drainage and operations in the open-pit mine, the spoil dump is used to reconstruct the ecological aquifer for water storage, and used as ecological water for the mining area; water is stored through the Quaternary loose aquifer injection wells and the coal seam deep aquifer injection wells, and used as domestic water, agricultural water and ecological water around the mining area.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The construction method of the three-dimensional storage system of the present invention comprehensively considers the geological conditions, hydrogeological conditions and environmental protection requirements of the mining area, establishes an advanced three-dimensional storage system, can effectively manage and utilize the water resources of the open-pit mine, reduce the negative impact on the environment, improve the recycling efficiency of water resources, and replenish groundwater resources to achieve the protection and restoration of groundwater resources; 2. The three-dimensional storage system of the present invention makes full use of the surface and bottom water storage facilities in the mining area, combines the ecological aquifer reconstructed in the dump, the shallow aquifer on the coal seam roof and the deep aquifer recharge method, and forms a coordinated system of three-dimensional storage of mine water and protection of groundwater resources, which can greatly increase the utilization rate of mine water and further maintain the attributes of mine water resources, solving the existing problems of single storage method of mine water, easy to be polluted, low utilization rate, and difficult long-term storage; 3. The surface water storage tanks and pit bottom water storage tanks in the mining area in this three-dimensional storage system can temporarily store the water gushing out of the open-pit mine and allocate it at any time as ecological water for mining area production and agricultural water for life around the mining area; the ecological aquifer is reconstructed in the dumping yard in the mining area, which is conducive to the reconstruction of the damaged strata, the optimization of the dumping plan and the environmental restoration; the quaternary groundwater replenishment can raise the groundwater level and realize the protection of the aquifer and water resources; the coal seam floor aquifer replenishment provides a deep repair path for the storage, protection and utilization of water resources in open-pit coal mines; 4. The three-dimensional storage system of the present invention helps to improve the safety and stability of mine water storage, reduce the negative impact of open-pit mine water inrush on the ecological environment, improve the storage efficiency of open-pit mine water resources, and realize efficient and multi-channel utilization of mine water resources; 5. The three-dimensional storage system of the present invention combines the topography and hydrogeological parameters of the mining area, comprehensively plans and uses a multi-mode integrated water storage system, effectively reduces the loss of groundwater resources, the area of ​​the drop funnel and the depth of the water level in open-pit mining, and ensures the long-term management and effective utilization of water resources in open-pit mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of the three-dimensional storage method of open-pit mine water; Figure 2 It is a schematic cross-sectional structure diagram of a three-dimensional storage system for open-pit mine water according to the present invention; Figure 3 It is a schematic diagram of the layout of water storage and recharging wells and monitoring wells for the Quaternary loose aquifer and the deep bedrock aquifer in the coal seam floor of the present invention; Figure 4 Schematic diagram of groundwater flow field in the Quaternary loose aquifer with recharge and storage.

[0017] Figure numerals: 1. open-pit mine; 2. overburden; 3. original aquifer; 4. original impermeable layer; 5. bedrock; 6. coal seam; 7. surface water storage system; 8. pit bottom water storage system; 9. spoil dump reconstruction ecological aquifer storage system; 10. Quaternary loose aquifer storage system; 11. Bedrock aquifer storage system deep in the coal seam floor; 12. recharge well; 13. reinforced slope; 14. reconstructed impermeable layer; 15. Quaternary groundwater flow line; 16. Quaternary loose aquifer recharge well; 17. water cut-off curtain. DETAILED DESCRIPTION

[0018] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figures 1 to 4 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0019] like Figure 2 As shown, open-pit mining of coal mines is a process of excavating shallow coal seams by open-pit mining and forming an open-pit mine 1 at the excavation point. The geological section of the open-pit mine area generally includes a covering layer 2, an original aquifer 3, an original impermeable layer 4, a bedrock 5, a coal seam 6 and a deep bedrock aquifer in the bottom of the coal seam from top to bottom. In the process of open-pit mining of coal mines, an open-pit mining area will be formed first and the original mined soil and rocks will be transferred to the outside of the mining area. As the mining area of ​​the open-pit mine 1 increases and the cost of earthwork transportation is reduced, the working surface area opposite to the mining direction of the open-pit mine 1 is used as an internal dumping ground for storing Quaternary gravel and rock blocks stripped from the mining area of ​​the mining area, thereby reducing the cost of earthwork transportation and gradually realizing the ecological restoration of the mining area.

[0020] like Figure 1~2 As shown, the present invention discloses a three-dimensional storage method suitable for open-pit mine water, and the three-dimensional storage method comprises the following steps: 1. Carry out regional geological and hydrogeological surveys in the open-pit mining area to obtain the regional topographic and geomorphic parameters of the open-pit mining area, as well as the hydrogeological parameters of the dump, the Quaternary aquifer and the deep bedrock aquifer in the coal seam floor; the hydrogeological parameters include the water level of the aquifer, the permeability of the aquifer, the water storage coefficient of the aquifer, the amount of water in the mine, the water inflow point of the mine, the mining plan, the size of the dump and the permeability of the dump. The regional topographic and geomorphic map of the mining area is detected by remote sensing technology to obtain the regional topographic and geomorphic map and stratigraphic columnar map of the mining area; the groundwater level contour map of the shallow Quaternary aquifer in the coal seam roof, the water level contour map of the sandstone confined aquifer in the deep coal seam floor, the amount of water in the mine, the water inflow point of the mine, etc. are obtained through construction survey drilling.

[0021] 2. Determine the water inflow and water quality characteristics of the open pit 1, and establish a dynamic monitoring system and data collection mechanism for the water inflow of the mine. Determine the water quality standards for the water inflow of the mine and the water quality standards for the five storage systems, namely, the surface water storage system 7, the pit bottom water storage system 8, the waste dump reconstructed ecological aquifer storage system 9, the Quaternary loose aquifer storage system 10, and the deep bedrock aquifer storage system 11 of the coal seam floor. Combined with the water inflow of the mine, determine the storable water volume of the five storage systems.

[0022] The following is an example of an open-pit mine in Inner Mongolia: A large amount of mine water gushing occurs during the mining of an open-pit mine in Inner Mongolia. Due to the limited water storage locations and imperfect water storage methods in the mining area, a large amount of water resources are wasted. At the same time, a large amount of drainage causes the groundwater level of the main water-filled Quaternary loose aquifer to drop by more than 30m at 5km in the mining area. In addition, due to the serious leakage of stripping deposits in the mine dump, the ecological reclamation of the dump is difficult. In order to alleviate the water use problem in the mining area and the surrounding areas of the mining area during production, as well as the ecological restoration of the dump after the pit is closed and the groundwater level restoration of the Quaternary aquifer, the construction method of the open-pit mine 1 three-dimensional storage system of the present invention is adopted to achieve safe and efficient storage and utilization of mine water resources.

[0023] The water inflow of the mine is about 84000m 3 / d, and established a dynamic monitoring system for mine water inflow to determine the water quality characteristics of mine water inflow as shown in Table 1.

[0024] Table 1 Water quality characteristics of mine water inflow: .

[0025] 3. Plan a three-dimensional storage system for open-pit mine water and carry out construction according to the process requirements of the three-dimensional storage system.

[0026] The three-dimensional storage system includes five storage systems: surface water storage system 7, pit bottom water storage system 8, spoil dump reconstructed ecological aquifer water storage system 9, Quaternary loose aquifer water storage system 10 and coal seam floor deep bedrock aquifer water storage system 11. Combined with the water gushing volume of the open-pit mine 1, the corresponding water quality standards and storable water volume of the five storage systems are determined.

[0027] Surface water storage system 7, pit bottom water storage water storage system has no additional requirements for the quality of stored water. The main water source of mine water is the Quaternary aquifer, so the waste dump reconstructed ecological aquifer and the Quaternary loose aquifer can be used to store mine water. The water quality of mine water is better than that of the coal seam floor aquifer, so the deep bedrock aquifer of the coal seam floor can also be used to store mine water. Combined with the mine water inflow of open pit 1, the storage water volume that can be accommodated by the five storage systems is determined.

[0028] 1. Specific construction steps of surface water storage system 7.

[0029] Conduct geological surveys on the open-pit mine area to obtain soil type and groundwater level parameters, plan multiple reservoir locations in the eastern area of ​​the open-pit mine area where the geological structure is stable, the groundwater level is low, and there are no adverse geological bodies; design the volume, depth and anti-seepage measures of the reservoir.

[0030] The surface water storage system 7 has three water storage tanks, each with a length, width and height of 70m, 20m and 2m respectively, with a capacity of about 2800m 3 Excavate the reservoir to form a reservoir body that meets the design, lay HDPE anti-seepage membrane or concrete lining, and complete the anti-seepage treatment of the pool bottom and pool wall.

[0031] Install a drainage system consisting of water collection wells and drainage pipes, and lay water diversion pipes to drain rainwater and mine water. Equip the reservoir with a pH sensor and turbidity meter to form an automatic water quality monitoring system, and monitor the changes in water quality in the reservoir. Establish a regular inspection mechanism for the surface water storage system 7, clean the sediment in the reservoir and check the anti-seepage system.

[0032] 2. Specific construction steps of the pit bottom water storage system 8.

[0033] Determine the water accumulation area at the bottom of open pit 1 and the expected amount of water accumulation, and design the shape and volume of the reservoir. Excavate the open pit bottom reservoir, ensure the stability of the bottom and surrounding rocks of the reservoir, and use grouting technology to reinforce the reservoir floor to prevent settlement and leakage. Lay HDPE anti-seepage membrane or concrete lining, double-layer waterproof concrete sandwiched with anti-seepage membrane, and complete the construction of the anti-seepage layer. Lay out a water circulation system consisting of water diversion pipes and drainage pipes to drain rainwater and mine water; set up a fully automatic water level monitor for the reservoir to track the water level in real time. Establish a regular inspection mechanism for the pit bottom water storage system, clean the sediment in the reservoir and inspect the anti-seepage system.

[0034] 3. Specific construction steps of the dump site to reconstruct the ecological aquifer water storage system 9.

[0035] A damage assessment is conducted on the thickness, lithology, permeability, strength of the original aquifer and original impermeable layer of the open-pit mine 1, as well as the scope and extent of damage to the open-pit mine 1. The hydrogeological parameters of the original aquifer 3 and the original impermeable layer 4 of the open-pit mine 1 are obtained through geological exploration, drilling sampling, and indoor testing.

[0036] A relationship curve between the groundwater level depth and vegetation coverage in the open-pit mining area was established. The thickness of the artificially reconstructed aquifer and the depth of the impermeable layer were designed based on the relationship curve. It was determined that the groundwater level should be less than 1.5m deep and the impermeable layer should be within 1.5m of the surface of the dump site to maintain ecological water use on the surface of the dump site.

[0037] The reconstructed waterproof layer 14 is formed by combining natural materials such as clay or bentonite in the mining area with polymer synthetic materials to form a composite waterproof layer material with good construction performance. The thickness of the reconstructed waterproof layer 14 should be greater than or equal to the thickness of the original waterproof layer and should be connected to the original waterproof layer.

[0038] The Quaternary gravel and rock blocks stripped from the mining area are used as aquifer materials. Grouting pumps and rollers are used to construct the dump site reconstructed aquifer in the inner dump site by grouting and compaction methods. The thickness of the ecological aquifer reconstructed in the dump site should be less than or equal to the thickness of the original aquifer and connected to the original aquifer, and it is ensured that the construction process can effectively fill the voids and cracks in the aquifer. After the construction of the ecological aquifer reconstructed in the dump site is completed, grouting is performed in the slope area to form a reinforced slope 13 to ensure the stability of the slope. The width of the grouting reinforcement area is calculated using the empirical formula of the water-bearing or water-conducting fault water-blocking coal (rock) pillar: .

[0039] In a specific embodiment, L is the width of the grouting reinforcement area / m; K is the safety factor, which is 5; M is the thickness of the ecological aquifer reconstructed by the spoil dump / m, which is 60m; p is the actual head value at the maximum water storage capacity of the ecological aquifer reconstructed by the spoil dump / MPa, which is 0.6MPa; Kp is the tensile strength of the grouting reinforced section rock-concrete composite / MPa, which is 4.0MPa, and the construction width of the slope grouting reinforcement area for reconstructing the ecological aquifer of the spoil dump is 100.6m.

[0040] Construct a phased pile hole pressure-type anti-seepage wall or a trench-filled waterproof wall to prevent the lateral loss of the restored shallow water, and the horizontal aquiclude is completed when the open-pit mine is closed. Carry out quantitative evaluation of parameters and calculation of recharge water volume under different recharge conditions for the ecological aquifer reconstructed in the spoil dump, use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, and runoff time of the groundwater in the ecological aquifer reconstructed in the spoil dump, study the hydrodynamic field and migration and diffusion laws of characteristic components under the recharge conditions of the ecological aquifer reconstructed in the spoil dump, and carry out slope stability, recharge environmental impact assessment, and safe mining impact assessment under the recharge conditions of the ecological aquifer reconstructed in the spoil dump.

[0041] 4. Specific construction steps of the Quaternary loose aquifer water storage system 10.

[0042] Conduct hydrogeological exploration and pumping tests of the shallow Quaternary aquifer in the coal seam roof of the open-pit mine area to identify the hydrogeological parameters and groundwater runoff characteristics of typical recharge areas; The east side of the open pit 1, which is downstream of the groundwater runoff direction of the open pit and has strong stratum permeability, was selected to carry out drainage water recharge. Multiple recharge wells 12 were constructed in the recharge area as injection wells and observation wells. Groundwater automatic monitoring instruments were installed in the observation wells to test the water level, water temperature and conductivity data of the Quaternary loose aquifer online, and to carry out water level and water quality monitoring during the recharge process. Figure 3 As shown in the figure, there are 7 injection wells and observation wells in total. Well No. 1 is used as an injection well, and the recharge water volume can reach 200m 3 / h, the other 6 wells are observation wells, and the 6 observation wells are arranged on the rear side of the injection well in the form of vertices and midpoints of the sides of an equilateral triangle; the injection well has a full wellbore diameter of Φ450mm, with casing of Φ273mm and filter tube of Φ273mm inserted; the monitoring well has a full wellbore diameter of Φ330mm, with casing of Φ108mm and filter tube of Φ108mm inserted.

[0043] During the recharge process of the Quaternary loose aquifer, samples of groundwater were taken to test suspended matter, organic matter, microorganisms, and special indicator components of mine water. The overall water quality of the Quaternary drainage was better than that of mine water, and it was determined that the Quaternary drainage could be used for "raw water recharge" for the Quaternary recharge.

[0044] like Figure 4 The schematic diagram of the groundwater flow field of the Quaternary loose aquifer recharge storage is shown in the figure. The quantitative evaluation of the parameters under the original hydrogeological conditions and different recharge conditions and the calculation of the recharge water volume are carried out. The GMS numerical simulation software is used to simulate and calculate the water mixing ratio, runoff velocity, runoff time and discharge water volume of the Quaternary loose aquifer groundwater. The hydrodynamic field and the migration and diffusion laws of the characteristic components under the recharge conditions of the Quaternary loose aquifer are studied. It is determined that a single well of 200m is carried out in the downstream of the overall groundwater flow direction, that is, outside the water cut-off curtain 17 on the east side of the open-pit 1. 3 / d of recharge volume, the Quaternary loose aquifer water storage system 10, the Quaternary loose aquifer recharge well 16 and the Quaternary groundwater flow line 15 are as follows Figure 4 Carry out the environmental impact assessment of the recharge of the Quaternary loose aquifer and the impact assessment of safe mining, with a single well of 200m 3 The recharge scheme of / d has little impact on the drainage of open pit 1.

[0045] 5. Specific construction steps of the deep bedrock aquifer water storage system 11 in the coal seam floor.

[0046] Combined with the on-site water pressure test phase and past monitoring and detection data, the ground recharge holes were constructed in the east wall area of ​​open-pit mine 1, which is convenient for ground water and power supply, close to the reservoir, avoids land acquisition costs, is easy to maintain, and has good permeability of the recharge target layer.

[0047] Carry out quantitative evaluation of parameters under original hydrogeological conditions and different reinjection conditions, and calculate the reinjection water volume. Use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, runoff time, and discharge volume of deep groundwater in the coal seam floor. Study the hydrodynamic field and migration and diffusion laws of characteristic components under the reinjection conditions of deep aquifers in the coal seam floor. Carry out environmental impact assessment, water inrush hazard classification, and safe mining impact assessment under the reinjection conditions of deep coal seam floor.

[0048] 4. Determine the water use channels and principles in the open-pit mine area. Based on the operation plan of the open-pit mine 1, use the surface water storage system 7, the pit bottom water storage system 8, the spoil dump reconstructed ecological aquifer water storage system 9, the Quaternary loose aquifer water storage system 10 and the coal seam floor deep bedrock aquifer water storage system 11 to dynamically store and use water, and complete the three-dimensional storage and resource utilization of water resources in the open-pit mine area.

[0049] Water use includes five ways: production water in the mining area, ecological water in the mining area, domestic water around the mining area, agricultural water around the mining area, and ecological water around the mining area. The principle of water use is to give priority to production and ecological water in the mining area, and secondly to domestic water, agricultural water, and ecological water around the mining area.

[0050] The water storage principle is determined according to the amount of water that can be stored in the mining area, the water use route and the water use principle. During the drainage and operation of the open-pit mine 1, surface water reservoirs and pit bottom water reservoirs are used for temporary water storage, and used for production and ecological water in the mining area, as well as for living and agricultural water in the surrounding areas of the mining area. Secondly, in combination with the different hydrogeological conditions of the open-pit mining area, the ecological aquifer, the loose aquifer of the Quaternary system and the bedrock aquifer deep in the coal seam floor are reconstructed using the spoil dump for recharging and storage; during the drainage and operation of the open-pit mine 1, the ecological aquifer is reconstructed using the spoil dump for water storage, and used for ecological water in the mining area; water is stored through the injection wells of the loose aquifer of the Quaternary system and the injection wells of the deep aquifer of the coal seam floor, and used for living water, agricultural water and ecological water in the surrounding areas of the mining area.

[0051] The three-dimensional storage system constructed by the present invention can effectively restore the aquifers and impermeable layers destroyed by open-pit mining operations, and establish hydraulic connections with the original aquifers. The rapid recovery of Quaternary groundwater after replenishment can raise the groundwater level, thereby improving the three-dimensional storage efficiency of open-pit mine water, effectively reducing the loss of groundwater resources in open-pit mining, the area of ​​the drop funnel and the depth of the water level drop, and can achieve high-efficiency, multi-channel and long-term utilization of mine water resources.

[0052] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A three-dimensional storage method for open-pit mine water, characterized in that: The three-dimensional storage method comprises the following steps: Step 1: Conduct regional geological and hydrogeological surveys of the open-pit mine area to obtain the regional topographic and geomorphic parameters of the open-pit mine area and the hydrogeological parameters of the dump, Quaternary aquifer, and deep bedrock aquifer in the coal seam floor; Step 2: Determine the water inflow and water quality characteristics of the open-pit mine (1), and establish a dynamic monitoring system for the water inflow and a data collection mechanism; Step 3: Plan a three-dimensional storage system for open-pit mine water. The three-dimensional storage system includes five types of storage systems: surface water storage system (7), pit bottom water storage system (8), spoil dump reconstruction ecological aquifer water storage system (9), Quaternary loose aquifer water storage system (10) and coal seam floor deep bedrock aquifer water storage system (11). Combined with the water inflow of the open-pit mine (1), determine the corresponding water quality standards and storable water volume of the five storage systems, and carry out construction according to the process requirements of the three-dimensional storage system; Step 4: Determine the water use channels and principles in the open-pit mine area. Based on the operation plan of the open-pit mine (1), use the surface water storage system (7), the pit bottom water storage system (8), the spoil dump reconstructed ecological aquifer water storage system (9), the Quaternary loose aquifer water storage system (10) and the coal seam floor deep bedrock aquifer water storage system (11) to dynamically store and use water, thereby completing the three-dimensional storage and resource utilization of water resources in the open-pit mine area.

2. The three-dimensional storage method for open-pit mine water according to claim 1, characterized in that: The hydrogeological parameters in step 1 include aquifer water level, aquifer permeability, aquifer water storage coefficient, mine water inflow, mine water inflow point, mine excavation plan, spoil dump size and spoil dump permeability.

3. The three-dimensional storage method for open-pit mine water according to claim 2, characterized in that: The specific construction steps of the surface water storage system (7) in step 3 are: Step S1: Conduct geological survey on the open-pit mine area to obtain soil type and groundwater level parameters; Step S2: planning several water reservoir locations in the open-pit mine area where the geological structure is stable, the groundwater level is low, and there is no adverse geological body; Step S3: Design the volume, depth and anti-seepage measures of the water reservoir, excavate the water reservoir to form a water reservoir body that meets the design, lay HDPE anti-seepage membrane or concrete lining, and complete the anti-seepage treatment of the pool bottom and pool wall; Step S4: installing a drainage system consisting of a water collection well and drainage pipes, and laying out water diversion pipes for draining rainwater and mine water; configuring a pH sensor and a turbidity meter for the water reservoir to form an automatic water quality monitoring system, and monitoring changes in the water quality of the water reservoir; Step S5: Establish a regular inspection mechanism for the surface water storage system (7), clean the sediment in the storage tank and inspect the anti-seepage system.

4. The three-dimensional storage method for open-pit mine water according to claim 3, characterized in that: The specific construction steps of the pit bottom water storage system (8) in step 3 are: Step L1: Determine the water accumulation area and estimated water accumulation volume at the bottom of the open pit (1), and design the shape and volume of the water reservoir; Step L2: excavate an open pit bottom water reservoir, ensure the stability of the bottom and surrounding rocks of the reservoir, and use grouting technology to reinforce the bottom plate of the reservoir to prevent settlement and leakage; lay HDPE anti-seepage membrane or concrete lining, double-layer waterproof concrete sandwiched with anti-seepage membrane, and complete the construction of the anti-seepage layer; Step L3: Lay out a water circulation system consisting of water diversion pipes and drainage pipes for diverting rainwater and mine water; install a fully automatic water level monitor on the reservoir to track the water level in real time; Step L4: Establish a regular inspection mechanism for the pit water storage system, clean the sediment in the storage tank and inspect the anti-seepage system.

5. The three-dimensional storage method for open-pit mine water according to claim 4, characterized in that: The specific construction steps of the dump site reconstruction ecological aquifer water storage system (9) in step 3 are: Step M1: Conduct damage assessment on the thickness, lithology, permeability, strength of the original aquifer and the original aquiclude of the open pit (1), as well as the scope and degree of damage to the open pit (1), and obtain the hydrogeological parameters of the original aquifer (3) and the original aquiclude (4) of the open pit (1) through geological exploration, drilling sampling, and indoor testing; Step M2: Establish a relationship curve between the groundwater level depth and vegetation coverage in the open-pit mine area, and design the thickness of the artificially reconstructed aquifer and the depth of the aquiclude according to the relationship curve to maintain ecological water use on the surface of the dump site; Step M3: using clay or bentonite natural materials existing in the mining area in combination with polymer synthetic materials to form a composite waterproof layer material with good construction performance as a reconstructed waterproof layer (14); the thickness of the reconstructed waterproof layer (14) should be greater than or equal to the thickness of the original waterproof layer and connected to the original waterproof layer; Step M4: Using the Quaternary gravel and rock blocks stripped from the mining area as aquifer materials, using grouting pumps and rollers, and adopting grouting and compaction methods to construct a reconstructed aquifer in the inner dump. The thickness of the reconstructed ecological aquifer in the dump should be less than or equal to the thickness of the original aquifer, and connected to the original aquifer, and ensure that the construction process can effectively fill the voids and cracks in the aquifer; Step M5: construct a phased pile hole press-in type anti-seepage wall or a trench pouring type waterproof wall to prevent the lateral loss of the restored shallow water. When the open-pit mine is closed, the horizontal waterproof layer is constructed; Step M6: Carry out quantitative evaluation of parameters and calculation of recharge water volume under different recharge conditions for the ecological aquifer reconstructed by the spoil dump, use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity and runoff time of groundwater in the ecological aquifer reconstructed by the spoil dump, study the hydrodynamic field and migration and diffusion laws of characteristic components under the recharge conditions of the ecological aquifer reconstructed by the spoil dump, and carry out slope stability, recharge environmental impact assessment and safe mining impact assessment under the recharge conditions of the ecological aquifer reconstructed by the spoil dump.

6. The three-dimensional storage method for open-pit mine water according to claim 5, characterized in that: Step M4: After the construction of the ecological aquifer reconstruction in the spoil dump is completed, grouting is performed in the slope area to form a reinforced slope (13) to ensure the stability of the slope. The width of the grouting reinforcement area is calculated using the empirical formula for the water-bearing or water-conducting fault water-blocking coal pillar: ； In the above formula, L is the width of the grouting reinforcement area / m; K is the safety factor, which is 2~5; M is the thickness of the ecological aquifer reconstructed by the dump / m; p is the actual head value of the ecological aquifer reconstructed by the dump at the maximum water storage capacity / MPa; K p It is the tensile strength of the rock-concrete composite in the grouting reinforcement section / MPa.

7. The three-dimensional storage method for open-pit mine water according to claim 1, characterized in that: The specific construction steps of the Quaternary loose aquifer water storage system (10) in step 3 are: Step N1: Conduct hydrogeological condition exploration and pumping test of the shallow Quaternary aquifer in the coal seam roof of the open-pit mine area to identify the hydrogeological parameters and groundwater runoff characteristics of typical recharge areas; step N2: Select an area downstream of the open-pit mine in the direction of groundwater runoff and with high stratum permeability to carry out drainage water recharge. Construct several recharge wells (12) in the recharge area as injection wells and observation wells. Install groundwater automatic monitoring instruments in the observation wells to test the water level, water temperature and conductivity data of the Quaternary loose aquifer online and carry out water level and water quality monitoring during the recharge process. There are a total of 7 injection wells and observation wells, with Well No. 1 serving as an injection well and the other 6 wells serving as observation wells. The 6 observation wells are arranged behind the injection well in the form of vertices and midpoints of the sides of an equilateral triangle. Step N3: sampling the groundwater of the aquifer during the recharge process of the Quaternary loose aquifer, and testing the suspended matter, organic matter, microorganisms, and special indicator components of mine water in the water sample; Step N4: Carry out quantitative evaluation of parameters under original hydrogeological conditions and different recharge conditions and calculate the recharge water volume. Use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, runoff time and discharge water volume of groundwater in the Quaternary loose aquifer. Study the hydrodynamic field and migration and diffusion laws of characteristic components under the recharge conditions of the Quaternary loose aquifer. Carry out environmental impact assessment and safe exploitation impact assessment of the Quaternary loose aquifer.

8. The three-dimensional storage method for open-pit mine water according to claim 1, characterized in that: The specific construction steps of the deep bedrock aquifer water storage system (11) in the coal seam floor in step 3 are: Step M1: Based on the on-site water pressure test phase and past monitoring and testing data, select a location to construct the ground recharge hole that is convenient for ground water and power supply, close to the reservoir, avoids land acquisition costs, is easy to maintain, and has good permeability in the recharge target layer; Step M2: Carry out quantitative evaluation of parameters under original hydrogeological conditions and different reinjection conditions and calculate reinjection water volume. Use GMS numerical simulation software to simulate and calculate the water mixing ratio, runoff velocity, runoff time and discharge volume of deep groundwater in the coal seam floor. Study the hydrodynamic field and migration and diffusion laws of characteristic components under reinjection conditions of deep aquifers in the coal seam floor. Carry out environmental impact assessment, water inrush hazard classification and safe mining impact assessment under deep reinjection conditions of the coal seam floor.

9. The three-dimensional storage method for open-pit mine water according to any one of claims 1 to 8, characterized in that: The water use channels in step 4 include production water in the mining area, ecological water in the mining area, domestic water around the mining area, agricultural water around the mining area, and ecological water around the mining area; the water use principle is to give priority to ensuring production and ecological water in the mining area, and secondly to ensuring domestic water, agricultural water, and ecological water around the mining area.

10. The three-dimensional storage method for open-pit mine water according to claim 9, characterized in that: In step 4, the water storage principle is determined based on the amount of water that can be stored in the mining area, the water use route and the water use principle. During the drainage and operation of the open pit (1), surface water reservoirs and pit bottom water reservoirs are preferentially used for temporary water storage, and used for production and ecological water in the mining area, as well as living and agricultural water in the vicinity of the mining area; Secondly, taking into account the different hydrogeological conditions in the open-pit mine area, the spoil dump under construction is used to reconstruct the ecological aquifer, the Quaternary loose aquifer and the deep bedrock aquifer in the coal seam floor for recharging and storage; during the drainage and operation period in the open-pit mine (1), the spoil dump is used to reconstruct the ecological aquifer for storage and use it as ecological water in the mining area; water is stored through the Quaternary loose aquifer injection well and the coal seam floor deep aquifer injection well, and used as domestic water, agricultural water and ecological water in the vicinity of the mining area.

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