Ecological restoration method for mine dump

Abstract

The invention relates to the technical field of ecological restoration, in particular to a mine waste dump ecological restoration method which comprises the following steps: dividing a waste dump into planting areas, installing detection equipment in each planting area, and monitoring various indexes of soil and environment in real time; a soil conditioner is customized and produced according to soil physicochemical property analysis; arranging an irrigation system for each planting area, and planting grass seeds and shrubs according to climate and soil conditions; strip-shaped ditches are dug between the adjacent planting areas, and prefabricated buried ecological restoration modules are arranged in the strip-shaped ditches to form planting grooves. By implementing the ecological restoration scheme, the physical and chemical properties of the soil are remarkably improved, the heavy metal content is remarkably reduced and is lower than the national soil environment quality standard limit value, and soil pollution is effectively eliminated. In addition, the proportion of soil aggregate structures is increased from 15% to 30%, the water retention capacity of the soil is remarkably improved, and more suitable environmental conditions are provided for vegetation growth.

Description

Technical Field

[0001] The invention relates to the technical field of ecological restoration, and in particular to an ecological restoration method for a mine spoil dump. Background Art

[0002] With the continuous expansion of mining activities, the ecological and environmental problems of mine spoil dumps, as the inevitable waste accumulation sites in the process of mineral mining, are becoming increasingly prominent. Traditional spoil dump treatment methods often lead to a series of environmental problems such as soil structure destruction, soil erosion, soil pollution and loss of biodiversity, which seriously affect the sustainable development of mining areas and the ecological security of the surrounding areas.

[0003] At present, the main challenges facing ecological restoration of mine spoil dumps include deterioration of soil physical and chemical properties (such as pH imbalance, lack of organic matter, insufficient content of nutrients and trace elements, low cation exchange capacity, etc.), soil structure destruction (loss of soil aggregate structure, reduced porosity), low vegetation coverage, and potential heavy metal pollution. These problems seriously restrict the natural recovery process of vegetation, making the spoil dump a barren land and unable to effectively perform its ecological service functions.

[0004] Traditional ecological restoration methods often adopt a single vegetation restoration measure and lack systematic and targeted soil improvement strategies. Therefore, there is an urgent need for a comprehensive ecological restoration method for mine spoil dumps that can restore vegetation cover and enhance the stability and self-recovery ability of the ecosystem on the basis of restoring the physical and chemical properties of the soil. Summary of the invention

[0005] The present invention aims at the technical problems existing in the prior art and provides an ecological restoration method for a mine spoil dump to solve the problem that the existing traditional ecological restoration method is single and has poor restoration effect.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: A method for ecological restoration of a mine spoil dump comprises the following steps:

[0007] Divide the dumping ground into planting areas, install testing equipment in each planting area, and monitor various indicators of soil and environment in real time;

[0008] Customized production of soil conditioners based on soil physical and chemical property analysis;

[0009] Set up irrigation systems for each planting area and plant grass and shrubs according to climate and soil conditions;

[0010] Dig strip trenches between adjacent planting areas and place prefabricated underground ecological restoration modules to form planting troughs;

[0011] Extract the valuable elements remaining in the tailings in the spoil dump and dispose of them harmlessly.

[0012] Based on the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the detection equipment is one or more of a soil moisture sensor, a pH value detector, and a heavy metal content analyzer.

[0014] Further, the analysis of soil physical and chemical properties includes the following steps:

[0015] Determine the proportion of sand, silt and clay in the soil through particle analysis, and analyze the porosity of the soil aggregate structure;

[0016] Measure soil pH in each planting area;

[0017] Measure the content of organic matter, nutrients, trace elements in the soil, and analyze the soil cation exchange capacity.

[0018] Further, the custom production of soil conditioner includes the following steps:

[0019] Add alkaline or acidic substances according to the soil pH value to adjust the soil pH value to an appropriate range;

[0020] Adding organic matter, nutrients and / or trace elements for their content and cation exchange capacity;

[0021] Add biochar, microbial agents and / or water-retaining agents according to the porosity of the soil aggregate structure.

[0022] Furthermore, if the soil pH is too high, add an appropriate amount of alkaline substances; if the pH is too low, add an appropriate amount of acidic substances;

[0023] If the soil organic matter content is low, add humic acid, animal and plant residues and organic materials;

[0024] The added amount of the biochar, microbial agent and / or water retaining agent is 1% to 5% of the soil mass.

[0025] Further, the irrigation system layout steps are as follows:

[0026] Select water sources around the mine as irrigation water sources, and lay water pipelines according to the terrain of the spoil dump;

[0027] Install irrigation equipment in the planting area and connect it to water pipelines;

[0028] Adjust the amount of water irrigation according to the soil moisture content in each planting area.

[0029] Further, the steps of planting grass seeds and shrubs are as follows:

[0030] Divide each planting area into slope area or flat area, and improve the soil environment according to the area type;

[0031] Prepare the soil in each planting area before planting to make the soil suitable for plant growth;

[0032] Plant shrubs in the planting area located in the slope area, and plant trees in the planting area located in the flat area;

[0033] Weed regularly and irrigate and fertilize according to soil moisture conditions and plant growth needs.

[0034] Furthermore, the underground ecological restoration module includes an integrally formed and multi-layered outer shell, wherein one or more water storage layers are laid in the topmost layer inside the outer shell; a soil improvement layer is also located below the water storage layer in the outer shell; and a grid-like vegetation support structure is also provided in the outer shell.

[0035] Further, the steps of extracting the valuable elements remaining in the tailings in the spoil dump and performing harmless treatment are as follows:

[0036] Preliminarily separate the minerals containing higher-grade valuable elements, further process the preliminarily separated minerals and extract the valuable elements;

[0037] Remove harmful substances from tailings residue after valuable elements are extracted to form stable solidified residue;

[0038] The solidified residue is mixed into the soil in the planting area to absorb the residual heavy metals in the residue.

[0039] The beneficial effects of the present invention are:

[0040] 1) Through the implementation of this ecological restoration program, the physical and chemical properties of the soil have been significantly improved. Before the restoration, the soil was acidic (pH 5.2), with a low organic matter content (1.5%), serious deficiencies in nutrients such as nitrogen, phosphorus, and potassium, and excessive heavy metal content. After the restoration, the soil pH was adjusted to a range suitable for plant growth (6.8), the organic matter content was increased to a medium level (3.0%), and the content of nutrients such as nitrogen, phosphorus, and potassium increased significantly to meet the basic needs of plants. At the same time, the heavy metal content was significantly reduced, all below the national soil environmental quality standard limit, effectively eliminating soil pollution. In addition, the proportion of soil aggregate structure increased from 15% to 30%, and the soil's water retention capacity was significantly improved, providing more suitable environmental conditions for vegetation growth.

[0041] 2) The restoration plan effectively promoted the restoration of vegetation through scientific and reasonable irrigation system design, suitable grass and shrub planting, and a planting pattern that combines trees, shrubs and grass. Before the restoration, the vegetation coverage rate was extremely low (<10%), the ecosystem stability was poor, and the biodiversity was low. After the restoration, the vegetation coverage rate was as high as over 90%, and shrubs, grass species and trees all showed good growth trends, and the vegetation survival rate and growth conditions reached a high level. This not only effectively curbed soil erosion, but also significantly improved the stability and biodiversity of the ecosystem. The lush growth of vegetation provides good coverage and protection for the soil, further promoting the improvement of the physical and chemical properties of the soil and the virtuous cycle of the ecosystem.

[0042] 3) Through detailed chemical analysis and physical beneficiation of tailings, valuable elements (such as iron, etc.) were successfully recovered, realizing the reuse of tailings resources. At the same time, the tailings residue after the extraction of valuable elements was harmlessly treated, and harmful substances were removed by chemical precipitation, solidification / stabilization, plant restoration and other methods to prevent secondary pollution to the environment. This combination of resource utilization and harmless treatment not only reduces the harm of tailings to the environment, but also creates economic benefits, achieving a win-win situation for environmental protection and resource development. Finally, the solidified tailings residue was mixed with the soil in the planting area, and the plants in the planting area were used to further absorb the heavy metals, realizing the natural restoration of the tailings and the comprehensive recovery of the ecosystem. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0044] Figure 2 It is a schematic diagram of the location of the planting area of ​​the present invention;

[0045] Figure 3 This is a schematic diagram of the structure of the underground ecological restoration module of the present invention.

[0046] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0047] 1. Shell; 1.1. Aquifer; 1.2. Soil improvement layer; 1.3. Vegetation support structure. DETAILED DESCRIPTION

[0048] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0049] like Figure 1-2 As shown, a method for ecological restoration of a mine spoil dump comprises the following steps:

[0050] Divide the dumping ground into planting areas, install testing equipment in each planting area, and monitor various indicators of soil and environment in real time;

[0051] Customized production of soil conditioners based on soil physical and chemical property analysis;

[0052] Set up irrigation systems for each planting area and plant grass and shrubs according to climate and soil conditions;

[0053] Dig strip trenches between adjacent planting areas and place prefabricated underground ecological restoration modules to form planting troughs;

[0054] Extract the valuable elements remaining in the tailings in the spoil dump and dispose of them harmlessly.

[0055] As an implementation mode, the detection equipment is one or more of a soil moisture sensor, a pH value detector, and a heavy metal content analyzer.

[0056] By monitoring soil moisture in real time, irrigation strategies can be adjusted in a timely manner to ensure that the soil maintains suitable moisture conditions, which is conducive to the recovery and growth of vegetation.

[0057] The pH tester can be used to understand the acidity and alkalinity of the soil, and then take necessary measures to adjust the soil pH to meet the needs of plant growth.

[0058] The heavy metal content analyzer can accurately measure the content of heavy metals in the soil, evaluate the degree of pollution, and provide a scientific basis for formulating soil remediation plans.

[0059] In addition, other types of detection equipment can be added to monitor other indicators in the soil and environment, such as soil organic matter content, nutrient content (nitrogen, phosphorus, potassium, etc.), soil temperature, air humidity, light intensity, etc., to provide support for the formulation of more scientific and reasonable ecological restoration plans.

[0060] As an implementation method, analyzing the physical and chemical properties of soil includes the following steps:

[0061] Determine the proportion of sand, silt and clay in the soil through particle analysis, and analyze the porosity of the soil aggregate structure;

[0062] Measure soil pH in each planting area;

[0063] Measure the content of organic matter, nutrients, trace elements in the soil, and analyze the soil cation exchange capacity.

[0064] As an implementation method, the custom production of soil conditioner includes the following steps:

[0065] Add alkaline or acidic substances according to the soil pH value to adjust the soil pH value to an appropriate range;

[0066] Adding organic matter, nutrients and / or trace elements for their content and cation exchange capacity;

[0067] Add biochar, microbial agents and / or water-retaining agents according to the porosity of soil aggregate structure;

[0068] Among them, particle analysis is to classify the particles in the soil according to size through physical or chemical methods, so as to determine the proportion of sand particles (particle size greater than 0.02mm), silt particles (particle size between 0.002mm and 0.02mm) and clay particles (particle size less than 0.002mm).

[0069] Sand: Soils with high sand content usually have good aeration, but poor water and fertilizer retention capabilities, and are prone to leaking water and fertilizer.

[0070] Silt: A moderate silt content helps the soil form a good aggregate structure and improves the soil's water retention and fertility.

[0071] Clay: Soil with high clay content has strong ability to retain water and fertilizer, but has poor aeration and is easily compacted.

[0072] Soil aggregate structure is an important indicator of soil fertility. The soil porosity can be further analyzed according to the particle size ratio. The porosity reflects the proportion of space occupied by air and water in the soil.

[0073] Appropriate porosity ensures that there is enough air and water in the soil for plant roots to breathe and grow. Too small a porosity will result in compacted soil with poor aeration; too large a porosity will cause the soil to leak water and fertilizer.

[0074] In this regard, the method of adding biochar, microbial agent and / or water retaining agent in this embodiment is as follows:

[0075] Mix biochar directly with the soil, spread it on the soil surface before tilling, and then till it into the soil. The mixing ratio depends on the specific conditions of the soil and the needs of the crop. The generally recommended addition amount is 1% to 5% of the soil mass.

[0076] Measure the pH of the soil, because different plants have different adaptability requirements for soil pH.

[0077] If the soil pH is too high or too low, add an appropriate amount of alkaline substances such as lime or gypsum, or acidic substances such as ammonium sulfate and ferrous sulfate to adjust the soil pH to an appropriate range.

[0078] Organic matter content is an important indicator of soil fertility, affecting the soil's ability to retain water and fertilizer and microbial activity.

[0079] Nutrient elements mainly include nitrogen, phosphorus, potassium and other major elements, while trace elements mainly include iron, zinc, copper and other major elements, which directly affect the growth and yield of crops.

[0080] Cation Exchange Capacity (CEC): reflects the ability of soil to adsorb and retain cations.

[0081] In this regard, for soils with low organic matter content, organic materials such as humic acid, animal and plant residues can be added to improve soil fertility.

[0082] According to the soil nutrient status, add chemical fertilizers or compound fertilizers containing corresponding nutrients to meet the growth needs of crops.

[0083] Original soil testing data:

[0084] Initial soil pH: 5.2 (acidic)

[0085] Organic matter content: 1.5% (low)

[0086] Nitrogen, phosphorus and potassium content: 0.08%, 0.05% and 0.6% respectively (all low)

[0087] Heavy metal content (such as lead, zinc, and cadmium): 2 times, 1.5 times, and 1 times the national soil environmental quality standard limit, respectively.

[0088] Improved soil data:

[0089] Soil pH after adjustment: 6.8 (suitable for plant growth)

[0090] Content after adding organic matter: 3.0% (medium)

[0091] After fertilization, the nitrogen, phosphorus and potassium contents are increased to 0.15%, 0.1% and 1.2% respectively (to meet the basic needs of plants)

[0092] The heavy metal content has been significantly reduced and is below the national soil environmental quality standard limit.

[0093] As an implementation method, in the ecological restoration project of mine spoil dumps, setting up a scientific and reasonable irrigation system for each planting area and selecting suitable grass species and shrubs for planting according to local climate conditions and soil characteristics are key steps to ensure the success of vegetation restoration and the stability of the ecosystem. The specific steps are as follows:

[0094] First, a detailed analysis of soil moisture conditions, plant water requirements, and rainfall data for each planting area is performed to determine the basic needs of the irrigation system. This includes determining the amount of irrigation, irrigation frequency, and irrigation method.

[0095] Choose the appropriate irrigation method based on the topography, soil characteristics and plant species of the planting area. Common irrigation methods include drip irrigation, sprinkler irrigation, micro-sprinkler irrigation and infiltration irrigation. Drip irrigation and micro-sprinkler irrigation are suitable for areas with complex terrain and poor soil water retention. They can accurately control the irrigation volume and reduce water evaporation and waste. Sprinkler irrigation is suitable for large flat areas and can irrigate quickly and evenly.

[0096] When designing an irrigation system, it is necessary to consider the reliability of the water source, the layout of the water pipeline, the selection of irrigation equipment, and the intelligence of the control system. With an intelligent irrigation control system, the irrigation volume can be automatically adjusted based on the data fed back by the soil moisture sensor to achieve precise irrigation.

[0097] In this embodiment, after on-site investigation by R&D personnel, it was found that the terrain of the spoil dump is complex, the slope is large in some areas, the soil water retention is poor, the selected grass species and shrubs have high water requirements and are more dispersed in distribution; the basic requirements of the irrigation system are determined as follows: to provide sufficient supplementary irrigation for vegetation during the dry season to ensure that the soil moisture content is maintained within an appropriate range.

[0098] The irrigation system is designed as follows:

[0099] Water source selection: Use water sources near the mine (such as rivers, reservoirs or groundwater) as irrigation water sources to ensure the reliability and stability of the water source.

[0100] Layout of water pipelines: According to the topography and vegetation distribution of the spoil dump, rationally plan the layout of the water pipelines to reduce pipeline length and energy consumption.

[0101] Irrigation equipment selection: Select high-efficiency and energy-saving irrigation equipment, such as intelligent drip irrigation controllers, micro-sprinkler heads, etc., to improve irrigation efficiency and water resource utilization.

[0102] Intelligent control system: Install soil moisture sensors and intelligent irrigation control systems to monitor soil moisture content in real time and automatically adjust irrigation volume according to preset irrigation strategies to achieve precise irrigation.

[0103] Irrigation amount and frequency:

[0104] Daily irrigation volume in dry season: 20-30 liters / square meter

[0105] Irrigation frequency: once a day to once every two days, adjusted according to soil moisture sensor data

[0106] Irrigation efficiency:

[0107] The intelligent irrigation system can save about 30% of water compared with traditional irrigation methods.

[0108] The soil moisture content is maintained in the optimal range of 60%-70%.

[0109] Plant configuration and planting are as follows:

[0110] Measures such as adding organic fertilizers (such as decomposed farmyard manure) and applying lime to adjust pH value were taken to improve the soil environment. At the same time, deep tillage was used to improve soil structure and enhance soil water and fertilizer retention capabilities.

[0111] A planting pattern that combines trees, shrubs and grasses is adopted, that is, shrubs (such as sea buckthorn) are planted in key areas such as slopes to stabilize the soil; grass seeds (such as alfalfa) and appropriate amounts of trees (such as locust trees) are planted in flat areas to build a multi-level, multifunctional ecosystem.

[0112] Before planting, the land should be prepared, including weeding and tilling. Then the plants should be planted according to the predetermined row spacing to ensure that the plants have enough growth space and light conditions. During the planting process, pay attention to keeping the soil moist to promote seed germination and seedling growth.

[0113] Weeds should be removed regularly to prevent them from competing with the plants for nutrients and light. At the same time, shrubs and trees should be properly pruned to maintain their good growth shape and ventilation and light transmission.

[0114] According to the soil moisture conditions and plant growth needs, timely irrigation and fertilization should be carried out. In the dry season or during the period of vigorous plant growth, increase the number of irrigations and the amount of fertilizers to meet the plant's needs for water and nutrients.

[0115] Vegetation survival rate:

[0116] Shrub survival rate: 90%

[0117] Grass seed survival rate: 95%

[0118] Survival rate of tree seedlings: 85% (attention should be paid to wind protection and sunshade measures in the early stage)

[0119] Vegetation growth:

[0120] One year after planting, the average height of the shrubs increased by 50 cm and the crown width expanded by 30%.

[0121] The grass seed coverage rate reaches over 90%, effectively curbing soil erosion.

[0122] As an implementation method, digging strip trenches between adjacent planting areas and placing prefabricated underground ecological restoration modules to form planting troughs is an innovative technical method in ecological restoration projects. The following is a specific example that explains this process in detail:

[0123] Based on factors such as terrain, soil conditions, and vegetation requirements, design a reasonable strip ditch layout and specifications for underground ecological restoration modules.

[0124] Prefabricated underground ecological restoration modules ensure good water retention, fertilizer retention and air permeability.

[0125] Use the measuring tool to accurately measure the target area to determine the exact location and size of the strip trench.

[0126] After the module is installed, use the excavated soil for backfilling. Pay attention to the uniformity and compactness of the backfill soil to ensure that the module can be stably fixed in the soil.

[0127] Plant suitable grass species, shrubs or trees in the planting troughs. According to the growth habits of the vegetation and soil conditions, the planting density and planting method should be reasonably determined.

[0128] According to the growth needs of vegetation, timely irrigation and fertilization should be carried out to ensure that vegetation can obtain sufficient water and nutrients to promote its healthy growth.

[0129] As a supplement, the buried ecological restoration module used in this embodiment is a prefabricated ecological engineering component that can be buried in the soil. It usually integrates multiple ecological restoration functions, such as water storage and water conservation, soil improvement, vegetation support, etc., aiming to promote the rapid recovery of vegetation and the reconstruction of the ecosystem by improving the soil environment and providing suitable growth conditions.

[0130] The underground ecological restoration module is often equipped with an aquifer or water-retaining material inside, which can effectively store and retain rainwater or irrigation water, providing a stable source of water for vegetation.

[0131] The modules contain organic matter, minerals or other soil conditioners, which are gradually released after being buried in the soil, improving the physical and chemical properties of the soil and increasing its fertility and water retention capacity.

[0132] See also Figure 3 The underground ecological restoration module includes an integrally formed and multi-layered outer shell 1, and one or more water storage layers 1.1 (such as polymer water-absorbing resin, natural limiting materials, etc.) are laid in the top layer inside the outer shell 1. The water storage layer 1.1 can effectively collect and store external water sources such as rainwater and irrigation water, and slowly release it to the surrounding soil and vegetation through capillary action or osmosis, providing a stable water supply.

[0133] The shell 1 also contains a soil improvement layer 1.2 located below the aquifer 1.1. The soil improvement layer 1.2 is composed of a mixture of organic matter (such as humus, compost), minerals (such as bentonite, perlite), microbial preparations, etc. in a certain proportion. After being buried in the soil, it will gradually decompose and release nutrients, improve the soil's pH, texture, structure and microbial community, improve the soil's fertility and water retention capacity, and create more suitable environmental conditions for vegetation growth.

[0134] A grid-like vegetation support structure 1.3 is also provided in the shell 1, and the vegetation support structure provides a stable growth space and support for the roots of the vegetation, while promoting full contact between the roots and the improved soil, thereby improving the survival rate and growth rate of the vegetation.

[0135] Aquifer Effects:

[0136] After a moderate rainfall, the aquifer can continue to provide water to the surrounding soil for 7-10 days.

[0137] Effect of soil improvement layer:

[0138] Release rate of organic matter and minerals in the modified layer: faster in the first three months, then gradually slowed down to a stable release

[0139] Soil aggregate structure formation speed: 6 months after planting, the proportion of soil aggregate structure increased to 30% (15 percentage points higher than the initial level)

[0140] Vegetation support structure effect:

[0141] Average distribution depth of vegetation roots: One year after planting, the root depth increases to 20-30 cm, fully in contact with the improved soil.

[0142] As an implementation method, a detailed chemical analysis is conducted on the tailings to determine the types and contents of valuable elements contained therein, as well as the types and concentrations of harmful substances.

[0143] According to the analysis results, physical mineral processing methods such as magnetic separation, flotation and gravity separation are used to preliminarily separate minerals containing higher grade valuable elements.

[0144] The initially separated minerals are further processed, such as crushing, grinding, and concentration, to increase the recovery rate of valuable elements.

[0145] In this embodiment, after multi-element analysis, the tailings of a molybdenum ore dressing plant were found to have a high iron grade of 2.34%, which has potential recovery value. Through magnetic separation test, an iron concentrate of about 43% was initially obtained, and after regrinding and reselection, an iron concentrate with a yield of 0.38%, a grade of 63.93%, and a recovery rate of 10.29% was finally obtained.

[0146] The tailings residue after the extraction of valuable elements is treated harmlessly to remove harmful substances and prevent environmental pollution. Treatment methods include chemical precipitation, solidification / stabilization, and phytoremediation.

[0147] Chemical precipitation method: Add chemical agents to the tailings to make heavy metal ions form insoluble precipitates, thereby achieving removal.

[0148] Solidification / stabilization method: Use cement, asphalt and other curing agents to wrap up the harmful substances in the tailings to form a stable solidified body.

[0149] Phytoremediation: Use heavy metal tolerant plants to absorb, accumulate and fix heavy metals in tailings to achieve natural restoration of tailings.

[0150] Through the medium magnetic-strong magnetic-flotation-selection process, a variety of valuable elements were recovered from the tailings, and the remaining tailings residues were solidified to effectively prevent the leakage and diffusion of heavy metals. Finally, the solidified tailings residues were mixed with the soil in the planting area, and the plants in the planting area were used to further absorb the heavy metals, thus achieving natural restoration of the tailings.

[0151] The comparison of soil remediation parameters before and after remediation is shown in the following table:

[0152]

[0153]

[0154] By supplementing the above data, we can more intuitively understand the specific effects of the ecological restoration plan for mine spoil dumps in each link and the significant changes before and after restoration, which further proves the feasibility and effectiveness of the plan.

[0155] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for ecological restoration of a mine spoil dump, characterized in that: The following steps are involved: Divide the dumping ground into planting areas, install testing equipment in each planting area, and monitor various indicators of soil and environment in real time; Customized production of soil conditioners based on soil physical and chemical property analysis; Set up irrigation systems for each planting area and plant grass and shrubs according to climate and soil conditions; Dig strip trenches between adjacent planting areas and place prefabricated underground ecological restoration modules to form planting troughs; Extract the valuable elements remaining in the tailings in the spoil dump and dispose of them harmlessly.

2. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: The detection equipment is one or more of a soil moisture sensor, a pH value detector, and a heavy metal content analyzer.

3. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: Analysis of soil physical and chemical properties includes the following steps: Determine the proportion of sand, silt and clay in the soil through particle analysis, and analyze the porosity of the soil aggregate structure; Measure soil pH in each planting area; Measure the content of organic matter, nutrients, trace elements in the soil, and analyze the soil cation exchange capacity.

4. The method for ecological restoration of a mine spoil dump according to claim 3, characterized in that: Custom production of soil conditioners includes the following steps: According to the soil pH value, add alkaline or acidic substances to adjust the soil pH value to the appropriate range; Adding organic matter, nutrients and / or trace elements for their content and cation exchange capacity; Add biochar, microbial agents and / or water retaining agents according to the porosity of the soil aggregate structure.

5. The method for ecological restoration of a mine spoil dump according to claim 4, characterized in that: If the soil pH is too high, add an appropriate amount of alkaline substances; if the pH is too low, add an appropriate amount of acidic substances; If the soil organic matter content is low, add humic acid, animal and plant residues and organic materials; The added amount of the biochar, microbial agent and / or water retaining agent is 1% to 5% of the soil mass.

6. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: The steps for laying out the irrigation system are as follows: Select water sources around the mine as irrigation water sources, and lay water pipelines according to the terrain of the spoil dump; Install irrigation equipment in the planting area and connect it to water pipelines; Adjust the amount of water irrigation according to the soil moisture content in each planting area.

7. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: The steps of planting grass seeds and shrubs are as follows: Divide each planting area into slope area or flat area, and improve the soil environment according to the area type; Prepare the soil in each planting area before planting to make the soil suitable for plant growth; Plant shrubs in the planting area located in the slope area, and plant trees in the planting area located in the flat area; Weed regularly and irrigate and fertilize according to soil moisture conditions and plant growth needs.

8. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: The underground ecological restoration module includes an integrally formed and multi-layered outer shell, wherein one or more water storage layers are laid in the topmost layer inside the outer shell; a soil improvement layer is also located below the water storage layer in the outer shell; and a grid-like vegetation support structure is also provided in the outer shell.

9. The method for ecological restoration of a mine spoil dump according to claim 1, characterized in that: The steps of extracting the valuable elements remaining in the tailings in the spoil dump and performing harmless treatment are as follows: Preliminarily separate the minerals containing higher-grade valuable elements, further process the preliminarily separated minerals and extract the valuable elements; Remove harmful substances from tailings residue after valuable elements are extracted to form stable solidified residue; The solidified residue is mixed into the soil in the planting area to absorb the residual heavy metals in the residue.

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