Landform-vegetation-hydrology-pond four-dimensional integrated comprehensive ecological restoration method suitable for open-cast mining field

Abstract

The invention relates to a landform-vegetation-hydrology-pond four-dimensional integrated comprehensive ecological restoration method suitable for an open-cast mining field, and belongs to the technical field of mine ecological restoration. Comprising the following steps of (1) landform and rock soil restoration, (2) soil vegetation restoration, (3) side slope hydrological regulation and control and (4) pond ecologication.According to the ecological restoration method, a four-dimensional integrated collaborative restoration technology system is adopted, and the ecological function of a mine is optimized through multi-dimension and multi-technology collaborative optimization.

Description

Technical Field

[0001] This invention relates to a comprehensive ecological restoration method integrating landform, vegetation, hydrology, and ponds, applicable to open-pit mines, and belongs to the technical field of mine ecological restoration. Background Technology

[0002] Mine ecological restoration involves using scientific and rational methods to repair and rebuild damaged mining area ecosystems, thereby promoting ecological recovery and improvement. With the shift in economic development philosophy from "emphasizing economic development while neglecting environmental protection" to "giving equal importance to economic construction and ecological protection," mine ecological restoration has become a national strategy and policy direction. The steep slopes formed by open-pit mining pose geological disaster risks, such as landslides and collapses. In particular, numerous open-pit quarries, due to their complex geological structures, are highly susceptible to collapses and other disasters, threatening the safety of surrounding residents. Furthermore, post-disaster restoration costs account for 20%-30% of the total investment in mining. This paper proposes a comprehensive ecological restoration method integrating landform, vegetation, hydrology, and ponds, suitable for open-pit mines. This method aims to ensure the stability of open-pit mine slopes and vegetation restoration, and to achieve integrated utilization of the mine pit, bringing significant ecological and economic benefits. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a four-dimensional integrated ecological restoration method for open-pit mines, which integrates landform, vegetation, hydrology and ponds. This ecological restoration method adopts a four-dimensional integrated collaborative restoration technology system, which optimizes the ecological function of the mine through multi-dimensional and multi-technology collaboration.

[0004] To address the above problems, the specific technical solution of this invention is as follows: A comprehensive ecological restoration method integrating landform, vegetation, hydrology, and ponds in open-pit mines, comprising the following steps: 1) Topographic and Soil Restoration: For the slope of the mining pit with an angle >30° in the treatment area, the slope is cut to form a stepped slope with an overall slope angle ≤30°, a slope angle ≤45°, and a platform width ≥3m. The crushed stone collected from the slope is backfilled to the bottom of the mining pit to form a flat site. Galvanized grating is laid along the slope from top to bottom. When laying the galvanized grating, it is necessary to ensure that each grating is in a taut state. The grating should be kept 3cm to 8cm away from the slope. After laying it smoothly along the slope, holes are drilled on the slope with a drilling rig, and long anchor rods and short anchor rods are used to fix it from top to bottom. 2) Soil and vegetation restoration: After the galvanized wire mesh is laid, a soil substrate is prepared and sprayed evenly onto the galvanized wire mesh using a hydroseeding device until it is completely covered, ensuring a thickness of not less than 80 mm. 8–12 hours after the soil substrate is sprayed, the prepared seed substrate is sprayed onto the soil substrate using a hydroseeding device to form a seed layer with a thickness of 2–3 cm. After the seed substrate is sprayed, the growth status of the grass is observed during the germination, turf establishment, and root recovery stages, gradually allowing it to enter a natural growth state. 3) Slope hydrological control: intercepting ditches are set up at the top of the slope and below the steps, and drainage ditches are set up on the slope to form a crisscross drainage network; submersible pumps are installed on the hard and flat bottom of the pond, and sprinkler heads are set up on the slope steps. The main pipeline is laid from the top of the slope along the slope direction and connected to the submersible pump at the bottom of the pond. Branch pipelines are laid on the steps and connected to the sprinkler heads to provide irrigation water for the daily maintenance of vegetation in the study area. 4) Pond Ecological Construction: During the pit backfilling process, a layered backfilling and layered compaction process is adopted. When filling, different sizes of crushed stones obtained from slope cutting are mixed to avoid leaving large gaps between stones. On the basis of the compacted crushed stones at the bottom of the pit, a 50cm layer of clay is laid to cover the bottom of the pit. Then, on the clay layer, a bentonite waterproofing blanket is laid flat on the bottom of the pond and the slope. The thickness of the blanket is generally 300mm, but it can be adjusted according to the actual situation. When laying, it is necessary to overlap the blanket from bottom to top. To enhance the stability of the bentonite waterproofing blanket, steel nails or iron strips can be used to reinforce the slope. After the waterproofing work is completed, a trial water storage test is conducted on the pond. The infiltration of the pond is observed for 3 consecutive days. If there is no sudden drop in water level, normal water storage can begin. After the pond is constructed, fish fry, algae and other organisms are introduced. It can not only be used to store surface water and infiltrated groundwater on the slope, but also serve as an ecological landscape. The water source of the pond at the bottom of the pit comes from the natural infiltration of groundwater and the interception and drainage regulation of surface water.

[0005] In step 1), the galvanized grating has a diameter of 2.0–2.4 mm, a mesh size of 50 mm × 50 mm–70 × 70 mm, and a width of 2–3 m. Initially, a row of U-shaped steel nails with a diameter of 6 mm is placed at the top of the slope as the main anchors for fixation, with a longitudinal spacing of more than 50 cm. Then, long anchor rods with a diameter of 3–4 mm and a length of 0.6–1.0 m and short anchor rods with a diameter of 3–4 mm and a length of 0.3–0.5 m are fixed from top to bottom, with the long and short anchor rods arranged alternately, with a longitudinal and transverse spacing of about 1 m. When anchoring, it is necessary to ensure that the length of the anchor rod protruding from the slope surface is not less than 50 mm, and the length embedded in the rock should be between 150 and 400 mm. The arrangement of long and short anchor rods should be adjusted according to the specific conditions of the slope. In areas with a larger slope angle, the number of long anchor rods should be increased, while in areas with a gentle slope and stable rock mass, short anchor rods can be used instead of long anchor rods.

[0006] In step 2), the soil substrate preparation process is as follows: 50-70 kg / m3 of grass fiber, 920-1000 kg / m3 of planting soil, 0.5-0.7 kg / m3 of water-retaining agent, and 1-1.8 kg / m3 of fertilizer are added sequentially to 980-1000 kg / m3 of water, stirred evenly, and then 0.5-0.7 kg / m3 of binder is added and stirred to form the soil substrate for hydroseeding.

[0007] In step 2), the seed substrate preparation process is as follows: 50-65 kg / m3 of wood fiber, 2-3.5 kg / m3 of seeds, 0.4-0.6 kg / m3 of water-retaining agent, and 0.4-0.7 kg / m3 of fertilizer are added sequentially to 980-1000 kg / m3 of water, stirred evenly, and finally 0.4-0.6 kg / m3 of adhesive is added.

[0008] In step 2), after the seed substrate is sprayed, the growth of the grass should be observed daily during the germination, establishment, and root recovery stages. The soil should be kept moist, and the amount of watering should be controlled according to the weather. In conjunction with watering, pest and disease control and topdressing during the growing season should be carried out. At the early stage of plant growth, apply 5-10g / m2 of urea and about 20g / m2 of compound fertilizer once. Water once every 15 days in spring and autumn, and once every 10 days in summer (excluding the rainy season). Watering should be done in the morning and evening. After the grass seedlings have established themselves and the seedlings are growing normally, the watering frequency should be gradually reduced after about three months to train the plants' adaptability. During the maintenance period of the following 1-2 years, especially in the dry season, regular care should be given according to the weather to gradually allow the grass to enter a natural growth state.

[0009] In step 3), the slope top intercepting ditch is used to intercept surface runoff at the top of the slope. The slope top intercepting ditch is set in a stable area 2-5m away from the top of the slope to intercept water from the top of the slope to the maximum extent. The step intercepting ditch is used to collect water from the slope and is located below the slope steps. A drainage ditch is set on the slope to guide the water flow to the bottom ecological pond. Both the intercepting ditch and the drainage ditch are made of C20 concrete and are constructed in sections. Each section is 20m long and expansion joints are set between the sections. The joints are 2cm wide and the joint filling material is extruded polystyrene board. Through the flow generation and diversion of the intercepting ditch and the drainage ditch, the surface precipitation is concentrated and collected to the water storage area at the bottom of the mine pit.

[0010] In step 3), the submersible pump is completely submerged in water, at a distance of not less than 3m from the toe of the slope, avoiding the catchment area; sprinkler heads are installed on the slope steps at intervals of 1.5 to 2m.

[0011] The beneficial effects of the above-mentioned structure in this application are as follows: By slope cutting, anchoring, and laying galvanized grid mesh, the stability of the slope is ensured. Soil matrix is ​​evenly sprayed onto the surface of the galvanized grid mesh, completely covering the mesh surface, and then seed matrix is ​​sprayed onto the surface, achieving an ecologically compatible state for the slope. Furthermore, by fully utilizing the topographic features and constructing intercepting (drainage) ditches, rainwater is concentrated and collected at the bottom of the mine pit through runoff diversion. Ponds are formed through natural groundwater infiltration and drainage regulation. This four-dimensional approach achieves comprehensive restoration of the open-pit mine, solving the problems of the traditional, singular, and ineffective restoration methods of legacy mines. It contributes a new restoration method and provides new scientific and technological support for mine restoration, possessing practical significance. Attached Figure Description

[0012] Figure 1 This is a flowchart of the method of the present invention.

[0013] Figure 2 This is a plan view of the research area of ​​this invention.

[0014] Figure 3 This is a typical cross-sectional view of the governance of the research area in this invention.

[0015] Figure 4 for Figure 3 A magnified view of a portion of the image.

[0016] Among them, 1—slope top intercepting ditch, 2—slope after clearing, 3—topsoil for planting shrubs and grass, 4—vines, 5—intercepting ditch, 6—original slope line, 7—crushed stone backfill compacted layer, 8—30cm waterproof blanket, 9—50cm clay layer, 10—pond, 11—groundwater level line, 12—rock and soil, 13—waste slag. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] This application selects an abandoned open-pit mine as the remediation site, conducts topographic mapping and geological surveys of the abandoned mine, and organizes and analyzes the survey results.

[0019] The survey results are as follows: the height of the northwest slope is 63m, the height of the southeast slope is 72m, the bottom elevation of the pit is 112m, and the average depth of groundwater is 7.2m.

[0020] The four-dimensional integrated management method for open-pit mines in this embodiment includes the following steps: 1. Slope clearing: For the slopes of the mining pits with an angle >30° in the treatment area, the slopes are cut and the gravel on the broken surface is cleared to form a stepped slope with an overall slope angle ≤30°, a slope angle ≤45°, and a platform width ≥3m. 2. The crushed stone collected from the slope is backfilled to the bottom of the mine pit to form a level site. During the backfilling process, layered backfilling and layered compaction are adopted. When filling, stones of different sizes obtained from the slope are mixed to avoid leaving large gaps between stones and improve the stability of the filling material. 3. After the slope preparation is completed, a row of U-shaped steel nails with a diameter of 6mm is placed at the top of the slope as the main anchor nails for fixation. The longitudinal spacing of the main anchor nails is greater than 50cm. Galvanized grating is laid along the slope from top to bottom. The wire diameter of the grating is 2.0 to 2.4mm, the mesh size is 50mm×50mm to 70×70mm, and the mesh width is 2 to 3m. When laying the galvanized grating, it is necessary to ensure that each grating is in a taut state. The grating should be kept 3cm to 8cm away from the slope. 4. After leveling and smoothing the slope, drill holes in the slope using a drilling rig. Fix the anchors from top to bottom using long anchors (3-4mm in diameter, 0.6-1.0m in length) and short anchors (3-4mm in diameter, 0.3-0.5m in length), with the long and short anchors staggered and spaced approximately 1m apart in both directions. When anchoring, ensure that the length of the anchor protruding from the slope is not less than 50mm, and the length embedded in the rock should be between 150-400mm. The arrangement of long and short anchors should be adjusted according to the specific conditions of the slope. In areas with a large slope angle, the number of long anchors should be increased, while in areas with a gentle slope and stable rock mass, short anchors can be used instead of long anchors, and the spacing can be adjusted appropriately. 5. A ring-shaped intercepting ditch is constructed at the top of the slope and below the steps, and a drainage ditch is arranged downwards along the slope. The intercepting and drainage ditches are made of C20 concrete, constructed in sections, each 20m long, with expansion joints 2cm wide between sections, and extruded polystyrene board as the joint filler. Through the intercepting (drainage) ditches, surface precipitation is concentrated and collected to the natural water storage area at the bottom of the mine pit; 6. After the galvanized grating is laid, prepare the soil substrate: Add grass fiber, planting soil, water-retaining agent, and fertilizer to water in sequence, stir evenly, then add adhesive and stir to form the soil substrate for hydroseeding; the water content is 980-1000 kg / m³. 3 The planting soil should be 920-1000 kg / m³. 3 Grass fiber content is 50-70 kg / m² 3 The water-retaining agent is 0.5–0.7 kg / m³. 3 Fertilizer application rate: 1–1.8 kg / m³ 3 The adhesive content is 0.5–0.7 kg / m³. 3Secondly, using a specialized hydroseeding machine, the prepared soil substrate is evenly sprayed onto the galvanized steel wire mesh until it is completely covered, ensuring a thickness of no less than 80 mm. After approximately 8–12 hours, once the soil substrate layer meets the required strength, the prepared seed substrate is sprayed onto the soil substrate using a hydraulic seeding machine to form a seed layer with a spraying thickness of 2–3 cm. Seed types include alfalfa, rose, tall fescue, and wisteria. The preparation process of the seed substrate is as follows: wood fiber, seeds, water-retaining agent, and fertilizer are added to water in sequence and stirred evenly. Finally, an adhesive is added and stirred evenly. The water concentration is 980–1000 kg / m³. 3 Wood fiber content is 50-65 kg / m³ 3 Seeds: 2-3.5 kg / m² 3 Water-retaining agent 0.4~0.6kg / m 3 Fertilizer application rate: 0.4–0.7 kg / m³ 3 and adhesive 0.4~0.6kg / m 3 .

[0021] 7. Utilizing natural rainfall and infiltrated groundwater, an ecological landscape pond measuring 173m × 95m × 8m was constructed. On the leveled ground at the bottom of the pit, a 50cm layer of clay was first laid to cover the bottom. On top of this clay layer, a 300mm thick bentonite waterproofing blanket was laid flat on the pond bottom, overlapping from bottom to top. To enhance the stability of the bentonite waterproofing blanket, steel nails or iron strips were used to reinforce the slope. After waterproofing was completed, a trial water filling test was conducted. Infiltration was observed for three consecutive days; no sudden drop in water level was observed, and normal water filling commenced. Once the pond was completed, fish fry and algae were introduced. It not only serves to store surface water and infiltrated groundwater from the slope but also provides an ecological landscape for viewing.

Claims

1. A comprehensive ecological restoration method integrating landform, vegetation, hydrology, and ponds, applicable to open-pit mines, characterized in that... Includes the following steps: 1) Topographic and Soil Restoration: For the slope of the mining pit with an angle >30° in the treatment area, the slope is cut to form a stepped slope with an overall slope angle ≤30°, a slope angle ≤45°, and a platform width ≥3m. The crushed stone collected from the slope is backfilled to the bottom of the mining pit to form a flat site. Galvanized grating is laid along the slope from top to bottom. When laying the galvanized grating, it is necessary to ensure that each grating is in a taut state. The grating should be kept 3cm to 8cm away from the slope. After laying it smoothly along the slope, holes are drilled on the slope with a drilling rig, and long anchor rods and short anchor rods are used to fix it from top to bottom. 2) Soil and vegetation restoration: After the galvanized wire mesh is laid, a soil substrate is prepared and sprayed evenly onto the galvanized wire mesh using a hydroseeding device until it is completely covered, ensuring a thickness of not less than 80 mm. 8–12 hours after the soil substrate is sprayed, the prepared seed substrate is sprayed onto the soil substrate using a hydroseeding device to form a seed layer with a thickness of 2–3 cm. After the seed substrate is sprayed, the growth status of the grass is observed during the germination, turf establishment, and root recovery stages, gradually allowing it to enter a natural growth state. 3) Slope hydrological control: intercepting ditches are set up at the top of the slope and below the steps, and drainage ditches are set up on the slope to form a crisscross drainage network; submersible pumps are installed on the hard and flat bottom of the pond, and sprinkler heads are set up on the slope steps. The main pipeline is laid from the top of the slope along the slope direction and connected to the submersible pump at the bottom of the pond. Branch pipelines are laid on the steps and connected to the sprinkler heads to provide irrigation water for the daily maintenance of vegetation in the study area. 4) Pond ecological construction: During the backfilling of the pit, a layered backfilling and compaction process is adopted. When filling, different sizes of crushed stones obtained from slope cutting are mixed to avoid leaving large gaps between stones. On the basis of the compacted crushed stones at the bottom of the pit, a 50cm layer of clay is laid to cover the bottom of the pit. Then, on the clay layer, a bentonite waterproof blanket is laid flat on the bottom of the pond and the slope. The thickness is generally 300mm, but it can be adjusted according to the actual situation. When laying, it is necessary to overlap the layers according to the bottom-up principle. To enhance the stability of the bentonite waterproof blanket, steel nails or iron strips can be used to reinforce the slope. After the waterproofing work is completed, a trial water storage test is conducted on the pond. The pond is observed for seepage for 3 consecutive days. If there is no sudden drop in water level, normal water storage begins. After the pond is built, fish fry, algae and other organisms are introduced. It can not only be used to store surface water and seepage groundwater on the slope, but also serve as an ecological landscape for viewing. The water source of the pond at the bottom of the pit comes from the natural seepage storage of groundwater and the interception and drainage regulation of surface water.

2. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 1), the galvanized grating has a diameter of 2.0–2.4 mm, a mesh size of 50 mm × 50 mm–70 × 70 mm, and a width of 2–3 m. Initially, a row of U-shaped steel nails with a diameter of 6 mm is placed at the top of the slope as the main anchors for fixation, with a longitudinal spacing of more than 50 cm. Then, long anchor rods with a diameter of 3–4 mm and a length of 0.6–1.0 m and short anchor rods with a diameter of 3–4 mm and a length of 0.3–0.5 m are fixed from top to bottom, with the long and short anchor rods arranged alternately, with a longitudinal and transverse spacing of about 1 m. When anchoring, it is necessary to ensure that the length of the anchor rod protruding from the slope surface is not less than 50 mm, and the length embedded in the rock should be between 150 and 400 mm. The arrangement of long and short anchor rods should be adjusted according to the specific conditions of the slope. In areas with a larger slope angle, the number of long anchor rods should be increased, while in areas with a gentle slope and stable rock mass, short anchor rods can be used instead of long anchor rods.

3. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 2), the soil substrate preparation process is as follows: at 980–1000 kg / m³ 3 Add 50-70 kg / m³ to the water sequentially 3 Grass fiber, 920-1000 kg / m 3 Planting soil, 0.5–0.7 kg / m² 3 Water-retaining agent and 1~1.8kg / m 3 Mix the fertilizer thoroughly, then add 0.5–0.7 kg / m³ of water. 3 The binder is mixed to form the soil substrate used for hydroseeding.

4. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 2), the seed substrate preparation process is as follows: at 980–1000 kg / m³ 3 Add 50-65 kg / m³ to the water sequentially 3 Wood fiber, 2-3.5 kg / m 3 Seeds, 0.4–0.6 kg / m³ 3 Water-retaining agent and 0.4~0.7kg / m 3 Mix the fertilizer thoroughly, and finally add 0.4–0.6 kg / m³ of fertilizer. 3 Adhesive.

5. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 2), after the seed substrate is sprayed, the growth of the grass should be observed daily during the germination, turf establishment, and root recovery stages. The soil should be kept moist, and the amount of watering should be controlled according to the weather conditions. Pest and disease control and topdressing during the growing season should be carried out in conjunction with watering. At the early stage of plant growth, a single application of 5-10 g / m² of urea should be applied. 2 Compound fertilizer approximately 20g / m 2 Water once every 15 days in spring and autumn, and once every 10 days in summer (excluding the rainy season), watering in the early morning or late evening. After the grass and seedlings have established themselves and are growing normally, gradually reduce the frequency of watering after about three months to help the plants adapt. During the subsequent 1-2 years of maintenance, especially during the dry season, provide regular care according to the weather conditions to gradually allow them to enter a natural growth state.

6. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 3), the slope top intercepting ditch is used to intercept surface runoff at the top of the slope. The slope top intercepting ditch is set in a stable area 2-5m away from the top of the slope to intercept water from the top of the slope to the maximum extent. The step intercepting ditch is used to collect water from the slope and is located below the slope steps. A drainage ditch is set on the slope to guide the water flow to the bottom ecological pond. Both the intercepting ditch and the drainage ditch are made of C20 concrete and are constructed in sections. Each section is 20m long and expansion joints are set between the sections. The joints are 2cm wide and the joint filling material is extruded polystyrene board. Through the flow generation and diversion of the intercepting ditch and the drainage ditch, the surface precipitation is concentrated and collected to the water storage area at the bottom of the mine pit.

7. The integrated ecological restoration method for open-pit mines, encompassing landform, vegetation, hydrology, and ponds, as described in claim 1, is characterized in that: In step 3), the submersible pump is completely submerged in water, at a distance of not less than 3m from the toe of the slope, avoiding the catchment area; sprinkler heads are installed on the slope steps at intervals of 1.5 to 2m.

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