Method for collaborative restoration of ecology and landscape of high-altitude open-pit limestone mine

Abstract

The application discloses a kind of high-altitude open-pit limestone mine ecological and landscape collaborative repair method, it is related to the technical field of ecological restoration.The method comprises: obtaining mine area topography, soil and vegetation data, and dividing mine area into forest-grass mixed planting repair area, grass species mixed sowing repair area and natural recovery area;Along contour line, build the ladder-shaped platform with anti-inclination angle;Excavate fish scale pit in forest-grass mixed planting repair area, plant spruce and mix oat, cold early grass, alfalfa and awn bunting, form the three-dimensional configuration structure of arbor and grass;Mixed sowing of grass species in grass species mixed sowing repair area Mixed sowing of vertical fringed brome, Chinese fescue, cold early grass and alfalfa, form perennial herb community;After cleaning dangerous rock in natural recovery area, it is recovered naturally.The present application constructs terrace arbor and grass landscape, pasture landscape and natural cliff landscape by zoned repair strategy respectively, realizes the ecological restoration and landscape reconstruction of high-altitude limestone mine.

Description

Technical Field

[0001] This application relates to the field of ecological restoration technology, and in particular to a method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas. Background Technology

[0002] Open-pit limestone mining generates a series of ecological and environmental problems, including surface damage, vegetation destruction, soil degradation, and landscape fragmentation. This is especially true in high-altitude, ecologically fragile areas where extreme climates and poor soil conditions increase the difficulty of restoration, becoming a significant bottleneck restricting regional ecological security and sustainable development. The Gannan Plateau, as an important ecological security barrier in the upper reaches of the Yellow River, is characterized by high altitude, a cold and humid climate, a short frost-free period, and frequent short-duration heavy rainfall, resulting in poor ecosystem stability. Therefore, restoring the ecological environment of historically abandoned open-pit limestone mining areas is of paramount importance.

[0003] Existing technologies offer a method for rapid ecological restoration and landscape reconstruction in mining areas, representing the latest direction in ecological restoration and landscape synergy. This method first completes ecological restoration based on the terrain, water bodies, and pollution conditions after mining, and then proceeds with landscape reconstruction. However, due to the large altitude difference in high-altitude open-pit limestone mining areas, there is significant spatial heterogeneity in climate conditions, soil properties, and vegetation adaptability at different elevations. The vegetation cover and soil improvement measures adopted in existing technologies cannot guarantee plant survival rates and community stability in different elevation areas of high-altitude open-pit limestone mining areas, resulting in a lack of reasonable integration between the restored landscape and the surrounding natural mountain landscape. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas, addressing the aforementioned technical issues.

[0005] The present invention adopts the following technical solution: This invention provides a method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas, comprising: The high-altitude open-pit limestone mining area is divided into forest-grass mixed planting restoration area, grass mixed seeding restoration area and natural restoration area according to the elevation value and slope. In the mixed forest and grassland restoration area and the mixed grass seeding restoration area, platforms are constructed along the topographic contour lines, and the slope of the platforms is adjusted to a preset angle range to form stepped slopes. In the mixed forest-grassland restoration area, fish-scale pits arranged in a triangular pattern are excavated on the stepped slopes. Trees are planted on the stepped slopes and in the fish-scale pits, and annual and perennial grasses are mixed and sown on the stepped slopes to obtain a three-dimensional tree-grass configuration structure, forming a terraced landscape and a tree-grass landscape. In the grass seed mixed-sowing restoration area, various herbaceous plants are mixed and sown on the stepped slopes to obtain herbaceous plant communities, forming a pasture landscape. Natural cliff landscapes are formed in the natural restoration area. By combining terraced landscapes with tree and grass landscapes, pasture landscapes, and natural cliff landscapes, the ecology and landscape of high-altitude open-pit limestone mining areas can be restored in a coordinated manner.

[0006] Preferably, the elevation of the mixed forest and grassland restoration zone is 2350m to 2400m, the elevation of the mixed grass seed restoration zone is 2400m to 2650m, and the natural restoration zone is an area with an altitude of 2400m or above and a slope of ≥70°.

[0007] Preferably, the anti-tilt angle of the platform is in the range of 2° to 5°; the slope adjustment angle of the platform is in the range of 20° to 25°.

[0008] Preferably, after forming the stepped slope, the method further includes: A retaining wall is constructed at the bottom of the stepped slope, including: Remove loose rocks and obstacles from the bottom working area of ​​the stepped slope, excavate the foundation pit to the bedrock, control the depth and bottom width of the foundation pit, lay a mortar cushion layer of specified thickness and compact the base. The wall is constructed using dry-laid blocks of 30cm or more in layers, with expansion joints set at specified intervals and filled with asphalt-impregnated hemp rope. A sand and gravel filter layer is backfilled on the back of the wall.

[0009] Preferably, the excavation process of the fish-scale pit specifically includes: Layout and positioning are carried out on the stepped slope surface of the mixed forest and grassland restoration area; Excavate fish-scale pits of a specified size according to the triangular arrangement and the preset pit spacing; Set a preset angle of inclination at the bottom of the fish-scale pit and lay capillary trenches, then fill it with a mixture of topsoil and decomposed organic fertilizer in a preset ratio.

[0010] Preferably, in the mixed forest-grass restoration area, the annual grass species is oat, and the perennial grass species are Kentucky bluegrass, alfalfa and awnless bromegrass, with a mixed planting ratio of oat:Kentucky bluegrass:alfalfa:awnless bromegrass = 3:3:2:2. In the mixed grass species remediation area, the mixed grass species include: crested wheatgrass, Chinese fescue, Kentucky bluegrass, and alfalfa, with a mixed ratio of crested wheatgrass: Chinese fescue: Kentucky bluegrass: alfalfa = 4:3:2:1.

[0011] Preferably, during the formation of the stepped slope, the following steps are further included: When constructing the slope, maintain a reverse inclination angle of 2° to 5° so that the platform can collect rainwater by itself; Construct multiple non-concrete drainage channels in accordance with the principle of decentralized drainage to overflow and discharge the excess rainwater to the natural channel.

[0012] Preferably, the method further includes quantitatively evaluating the landscape coordination degree after restoration, specifically including: Use the landscape coordination degree index to evaluate the coordination degree between the restored area and the surrounding natural landscape. The landscape coordination degree index is based on the analysis of the RGB band of the UAV image, and the formula is: ; In the formula, is the landscape coordination degree index, , and are the average RGB values of the restored area respectively, , and are the average RGB values of the surrounding natural reference area respectively; When LCI > 0.85, it is determined as excellent coordination, and when 0.75 < LCI ≤ 0.85, it is determined as good coordination.

[0013] Preferably, the slope safety of the stepped slope is verified by the limit equilibrium method, and the formula is: ; In the formula, is the slope safety factor, is the effective soil cohesion, is the effective soil internal friction angle, is the weight per unit width of the landslide body, is the arc length of the sliding surface, is the pore water pressure, is the inclination angle of the sliding surface, is the designed anti-sliding force of the retaining wall; when , it indicates that the stepped slope meets the safety requirements.

[0014] The above at least one technical solution adopted by the present invention can achieve the following beneficial effects: In the method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas provided by this invention, differentiated design by zone is adopted. In the mixed planting restoration area with low elevation values, a three-dimensional configuration of trees and grasses is used, with annual and perennial grass species mixed sowing. Annual grass species can quickly stabilize the soil and provide a stable soil environment for tree growth, solving the technical problem of low tree survival rate caused by freeze-thaw cycles and strong winds in low elevation areas. The herbaceous community formed by perennial grass species has a strong ability to protect slopes and stabilize soil. Its leaves and stems can slow down the formation of rainwater runoff. Even after runoff occurs, it can reduce the erosion energy of the slope soil, thereby ensuring the long-term stability of the slope ecosystem. In the mixed planting restoration area with high elevation values, a variety of wind-resistant and cold-resistant grass species are mixed sown. Through root interweaving, a stable plant community is quickly formed, effectively curbing soil erosion caused by short-term heavy rainfall. In the natural restoration area with high elevation values ​​and steep slopes, the original cliff landscape is preserved through natural restoration. While restoring ecological functions, the terraced slopes and the three-dimensional configuration of trees and grasses have created a landscape of terraced fields and trees and grasses, a grassland landscape of various herbaceous plants, and a natural cliff landscape in the natural restoration area. This has created a multi-layered landscape system that is in harmony with the surrounding natural and human environment. It fully adapts to the spatial heterogeneity of climate, wind, soil and other characteristics caused by changes in elevation in high-altitude mining areas, ensures the adaptability of plant communities in different elevation areas, and enables the restored vegetation to connect naturally with the surrounding native ecosystem, achieving landscape integration and overcoming the defect of disharmony between the restored landscape and the surrounding ecosystem.

[0015] In addition, this invention breaks through the separate thinking of ecological restoration and landscape reconstruction, and realizes true integrated synergy. It integrates the principles of landscape ecology into the entire process of ecological restoration, and incorporates landscape synergy considerations into the process of slope treatment, soil improvement and vegetation configuration, rather than the two-step model of completing ecological restoration first and then reconstructing the landscape. This makes the restored mining area achieve organic unity in both the function of the ecosystem and the aesthetic appeal of the visual landscape.

[0016] In summary, this invention achieves a systematic improvement in the ecological function and landscape effect of high-altitude open-pit limestone mining areas through a synergistic technical approach integrating zoning, engineering, vegetation, and landscape. It significantly improves vegetation survival rate and community stability, effectively prevents soil erosion, and organically integrates landscape restoration with regional cultural tourism development. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1A flowchart illustrating a method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas provided by this invention; Figure 2 The diagram shows the mining damage morphology of a method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas, which is provided by this invention. Figure 3 Orthophotos of ecological damage in a high-altitude open-pit limestone mining area, which are part of a collaborative restoration method for ecology and landscape in this invention. Figure 4 An ecological restoration area division plan for a method of synergistic restoration of ecology and landscape in a high-altitude open-pit limestone mining area provided by the present invention; Figure 5 A schematic diagram of the ecological restoration profile of a mining area, which is provided by the present invention for a method of synergistic restoration of ecology and landscape in a high-altitude open-pit limestone mining area. Figure 6 A cross-sectional view of a retaining wall for a method of synergistic restoration of ecology and landscape in a high-altitude open-pit limestone mining area provided by the present invention; Figure 7 A flowchart of retaining wall construction for a method of synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas provided by the present invention. Figure 8 A flowchart of a fish-scale pit tree planting method for a collaborative restoration of ecology and landscape in a high-altitude open-pit limestone mining area provided by the present invention. Figure 9 A sample plot layout diagram for a method of synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas provided by the present invention; Figure 10 Soil sampling photographs for a method of synergistic restoration of ecology and landscape in a high-altitude open-pit limestone mining area provided by the present invention; Figure 11 The ecological restoration effect diagram of the collaborative restoration method for ecology and landscape in high-altitude open-pit limestone mining areas provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in the specification without creative effort are within the scope of protection of this application.

[0020] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0021] Figure 1This is a schematic diagram of a method for the coordinated restoration of ecology and landscape in a high-altitude open-pit limestone mining area according to the present invention, which specifically includes the following steps: S101: High-altitude open-pit limestone mining areas are divided into forest-grass mixed planting restoration areas, grass seed mixed sowing restoration areas, and natural restoration areas according to elevation values ​​and slopes.

[0022] Specifically, data on the topography, soil, and vegetation of the mining area are obtained through remote sensing interpretation and ground surveying. (See [link to relevant documentation]). Figure 2 This image depicts the morphological damage caused by mining operations. Land suitability was assessed using the extreme condition method, and monitoring plots were established to obtain soil physicochemical indicators and vegetation growth parameters. The remote sensing imagery of ecological damage in the mining area visually demonstrates the scope, extent, and spatial distribution of the ecological damage. Figure 3 During the on-site investigation, information was obtained through reviewing documents and conducting interviews regarding the mining history, current land use, and local ecological protection plans of the mining area.

[0023] Based on the research on the climate characteristics of the mining area, the results of land suitability assessment, and the needs of ecological restoration and landscape synergy construction, and following the principle of "afforestation where suitable, grass planting where suitable, and consideration of landscape effects," a three-in-one synergistic restoration system of "engineering measures - plant configuration - landscape regeneration" is constructed. Following the technical process of "land suitability assessment - zoning - clearing dangerous rocks - leveling land - covering with topsoil - restoring vegetation," differentiated restoration is implemented in different zones to achieve synergistic improvement of ecological functions and landscape effects.

[0024] Land suitability assessment: Land damage in the mining area is mainly divided into two types: excavation damage and occupation, which are scattered. Based on this, it is divided into two assessment units: excavation damage unit and occupation unit. The excavation damage unit includes the mining area and mine roads, while the occupation unit includes the office and living area (Table 1).

[0025] Table 1. Characteristic Analysis Before and After Mining for Each Participating Unit Seven evaluation factors were selected: topographic slope, soil erosibility, effective soil layer thickness, soil texture, drainage conditions, water source security, and soil pollution level. Excavation loss units mainly include areas where land has been damaged by excavation, such as mining areas and mine roads. Land occupation units mainly include areas where land has been occupied by buildings and waste, such as office and living areas. The difference in suitability evaluation lies in the fact that excavation loss units are primarily affected by topographic slope and soil erosibility, while land occupation units are primarily affected by soil compaction and effective soil layer thickness (see Table 3). The extreme condition method was used for suitability evaluation, with the "minimum factor law" as its core principle, meaning that the land suitability level is determined by the most restrictive factor. Weights were determined using the Analytic Hierarchy Process (AHP). First, a judgment matrix was constructed, and experts were invited to conduct pairwise comparisons of the seven evaluation factors, assigning values ​​using a 1-9 scale. Then, the eigenvector corresponding to the largest eigenvalue of the judgment matrix was calculated, and after normalization, the weight vectors of each factor were obtained. Finally, the consistency ratio (CR) was calculated. If CR < 0.1, the consistency test was passed; otherwise, the judgment matrix was readjusted. Each factor is divided into three levels of suitability. Based on the suitability evaluation criteria and field data (Table 2), under the extreme condition method, the unit total score is the minimum value of the scores of each factor, and then the suitability level is divided according to the total score.

[0026] Table 2 Suitability Evaluation Criteria Based on the above criteria, the evaluation results show that the mining platform is suitable as an artificially assisted restoration area, the north slope is suitable as a natural restoration area, and the office and living area is suitable as a vegetation reconstruction area. To quantify the restoration potential, a Restoration Potential Index (RPI) = ∑(factor weight × factor score) is introduced to quantitatively evaluate the ease or difficulty of restoration. The results are shown in Table 3.

[0027] The study area was divided into three ecological restriction levels: extremely, severely, and moderate (Table 3). The mining platform was severely restricted, with no effective soil layer, a slope of 5°, and erosion >50%, resulting in a restoration potential index of 0.32. The north slope was extremely restricted, with a slope ≥70°, no effective soil layer, and widespread bare rock, resulting in a restoration potential index of only 0.15. The office and living area was moderately restricted, with soil compaction >80% and a soil layer thickness of 10–30 cm, resulting in a restoration potential index of 0.58.

[0028] Factor coupling analysis showed that when the slope was greater than 25° and the proportion of erosion gullies was greater than 30%, the recovery potential index decreased significantly by 62% (p < 0.01), and the slope and erosion showed a strong synergistic constraint. In areas with an effective soil layer thickness of less than 30 cm, the vegetation survival rate was significantly positively correlated with the soil layer thickness (R² = 0.87), and 30 cm was the critical soil layer thickness for vegetation establishment in the area.

[0029] The study area exhibits a distinct spatial ecological gradient: from the mining platform (slope 5°) to the north slope (slope ≥70°), the effective soil layer thickness increases from 0cm to 10cm and then decreases to 0cm in the bare rock area, forming a typical fragile ecological transition zone. This indicates that a zoned, classified, and differentiated precise restoration strategy should be adopted based on ecological limitation levels and key factors.

[0030] Table 3 Evaluation Results of Land to be Reclaimed Based on the land suitability assessment results, combined with factors such as mining area elevation, wind force, soil erosion, and the adaptability of vegetation growth to climate and landscape reconstruction requirements, three restoration areas were divided along the direction perpendicular to the contour lines. Figure 4 Differentiated restoration techniques were adopted for the experiment. In low-altitude areas (2350~2400m), a mixed sowing technique of trees and grass was used, while in high-altitude areas (2400~2650m), a mixed sowing technique of grass seeds was used. In steep slope areas above 2400m with a slope of ≥70°, which were formed by extensive blasting and mining, the terrain is steep and construction is difficult. A natural restoration model was adopted, which gradually achieved natural ecological restoration by clearing dangerous rocks and reducing human interference. At the same time, supporting engineering measures such as stepped slope construction, retaining wall protection, and planting trees in fish-scale pits were implemented to build an ecological-landscape collaborative restoration system and achieve zoned synergy between ecological restoration and landscape reconstruction. Based on land suitability levels (classified as suitable for cultivation, forestry, animal husbandry, and unsuitable), restoration potential index (RPI value range 0-1), and factor coupling analysis results (the restoration potential index significantly decreases by 62% when the slope is >25° and the proportion of gullies is >30%), combined with the mining area's elevation (2350m-2650m), wind force (annual average wind speed, etc.), soil erosibility, and vegetation climate adaptability, the area was divided along a direction perpendicular to the contour lines. Areas with an RPI ≥ 0.5 and a suitability level of suitable for forestry or animal husbandry were designated as mixed forest-grassland restoration areas or mixed grass seeding restoration areas; areas with an RPI < 0.3 and a suitability level of unsuitable were designated as natural restoration areas.

[0031] S102: In the mixed forest and grassland restoration area and the mixed grass seeding restoration area, a platform is constructed along the topographic contour line, and the slope of the platform is adjusted to a preset angle range to form a stepped slope.

[0032] Optionally, the preset anti-tilt angle ranges from 2° to 5°; the platform slope adjustment angle ranges from 20° to 25°.

[0033] Optionally, the formation process of the stepped slope also includes: maintaining a counter-inclination angle of 2° to 5° when constructing the platform so that the platform can collect rainwater on its own; and constructing multiple non-concrete drainage channels according to the principle of decentralized drainage to discharge excess rainwater into natural ditches.

[0034] Optionally, after the stepped slope is formed, the method further includes: constructing a retaining wall at the bottom of the stepped slope, specifically including: removing loose rocks and obstacles in the working area at the bottom of the stepped slope, excavating the foundation pit to the bedrock, controlling the depth and bottom width of the foundation pit, laying a mortar cushion layer of a specified thickness and compacting the base; using dry-laid blocks of greater than or equal to 30cm to construct the wall in layers, setting expansion joints at specified intervals and filling them with asphalt hemp rope, and backfilling a sand and gravel filter layer on the back of the wall.

[0035] Specifically, regarding the improvement of mining area topography, prevention and control of soil erosion, and landscape optimization, three core engineering measures are optimized and implemented based on the topographical features of the mining area and the requirements of tourism. These measures balance ecological protection and landscape harmony, taking into account the topography and land suitability evaluation results formed by mining operations, and considering both landscape effects and soil erosion control. Platforms are constructed or slopes are modified along contour lines to create a terraced landscape. Figure 5 When tidying up the platform, maintain a counter-tilt angle of 2° to 5° to ensure that it can collect rainwater and nourish vegetation. At the same time, in accordance with the principle of decentralized drainage, construct multiple small non-concrete drainage channels to discharge excess rainwater overflow into natural ditches, preventing large runoff from eroding the restoration area and surrounding soil and water loss. The slope gradient is controlled between 20° and 25°, with a slope height of about 6m. This ensures slope stability, reduces the erosive force of runoff from rainfall on the slope surface, and forms a terraced landscape with distinct layers, which is in harmony with the surrounding grassland and valley landforms. The loose slag heaps formed by open-pit mining are leveled, compacted, and covered with a mixture of topsoil and well-rotted organic fertilizer to improve soil fertility and provide a good foundation for vegetation growth. The roads in the mining area are deeply tilled, loosened, and leveled, and then covered with grass seeds, retaining their original function as pasture roads for the public to continue using when grazing, thus achieving ecological restoration of the roads. The abandoned buildings in the office and living areas are demolished, the ground is leveled, and then covered with a mixture of topsoil and well-rotted organic fertilizer to restore them to artificial pasture.

[0036] To address the issue of landslides and soil erosion caused by large amounts of loose slag heaps in mining areas, retaining walls were constructed at the bottom of the slopes after the slag heaps were leveled to ensure the safety of the loose slag while also maintaining aesthetic harmony with the landscape. Figure 6 The retaining wall is designed to be 3.5m high, with 2m above ground level, a foundation depth of 1.5m, a top width of 0.7m, a bottom width of 1.4m, a breast slope ratio of 1:0.4, and a back slope ratio of 1:0.2. Drainage pipes are laid in a zigzag pattern every 2m. The foundation at the bottom of the wall is 2.0m wide and covered with a 0.1m thick M10 mortar cushion layer. The wall construction and backfilling are carried out simultaneously. Expansion joints with a width of 2cm are constructed every 10m and filled with asphalt-impregnated hemp rope to a depth of not less than 150mm to improve the stability and durability of the retaining wall.

[0037] See Figure 7This is a flowchart of the retaining wall construction process. The retaining wall construction follows the principle of "foundation first, layered construction, and drainage consideration," and is divided into two core stages: foundation treatment and wall construction. In the foundation treatment stage, the site is first cleared, removing obstacles such as loose rocks and weeds from the work area. After surveying and setting out, the foundation pit is excavated to the bedrock using mechanical excavation, controlling the pit depth to 1.5m and the bottom width to 2.0m. Then, a 0.1m thick M10 mortar cushion layer is laid and the base is compacted to ensure that the compaction coefficient is not less than 0.9. If a soft soil layer is encountered, a 1.0m deep gravel replacement treatment is carried out. Dry-laid stone masonry is preferred during the wall construction phase. Stones with a particle size of not less than 30cm are used for layered construction. The total height of the wall is 3.5m (2m above ground). The breast slope ratio is controlled at 1:0.4. The drainage system is installed simultaneously during the masonry process. An expansion joint is set every 10m and filled with asphalt hemp rope. At the same time, a sand and gravel filter layer is backfilled on the back of the wall to ensure the structural stability and drainage performance of the retaining wall.

[0038] S103: Excavate fish-scale pits arranged in a triangular pattern on the slope surface of the stepped slope in the mixed forest-grass restoration area; plant trees on the slope surface of the stepped slope and in the fish-scale pits, and sow a mixture of annual and perennial grasses on the slope surface of the stepped slope to obtain a three-dimensional tree-grass configuration structure, so as to form a terraced landscape and a tree-grass landscape; sow a variety of herbaceous plants on the slope surface of the stepped slope in the grass seed mixed sowing restoration area to obtain a herbaceous plant community, so as to form a pasture landscape; and form a natural cliff landscape in the natural restoration area.

[0039] Optionally, in the forest-grass mixed planting restoration area, the annual grass species is oat, and the perennial grass species are Kentucky bluegrass, alfalfa and awnless bromegrass, with a mixed planting ratio of oat:Kentucky bluegrass:alfalfa:awnless bromegrass = 3:3:2:2. In the mixed grass species remediation area, the mixed grass species include: crested wheatgrass, Chinese fescue, Kentucky bluegrass, and alfalfa, with a mixed ratio of crested wheatgrass: Chinese fescue: Kentucky bluegrass: alfalfa = 4:3:2:1.

[0040] Specifically, based on the regional characteristics of high altitude, cold and damp climate, strong winds, poor soil, and frequent short-term heavy rainfall, the plant configuration scheme was optimized according to the principles of "high degree complementarity, coarse and fine complementarity, stress resistance complementarity, and rapid soil stabilization" to achieve synergy between rapid vegetation restoration and landscape optimization. Differentiated plant configuration patterns were adopted for different restoration areas. The optimization of plant configuration technology in this mine includes two main aspects: grassland restoration and tree planting. Combining the regional high-altitude climate characteristics and precipitation distribution patterns, and drawing on the phenological adaptation method in "Ecological Restoration of High-Altitude Mining Areas," grassland restoration first involves land reshaping and slope control through excavation and filling, with simultaneous soil covering, followed by manual harrowing and sowing of grass seeds. In terms of timeline, sowing began in May, seedling management started in June, coinciding with the region's concentrated rainfall period (July-September). Natural irrigation was utilized during the high-water season from July to September, and non-woven fabric was used for overwintering protection from October to April of the following year. Reseeding and fertilization were carried out after the spring thaw in April of the following year. The trees planted are spruce. Nurturing and management will be carried out within 3 years after planting. Sowing and initial irrigation will be completed in the first year, and drip irrigation will be carried out monthly from May to September in the second to third years, depending on the rainfall.

[0041] Forest-grass mixed planting restoration area (2350~2400m): The three-dimensional configuration mode of "tree + multi-grass mixed sowing" is adopted. The trees selected are spruce, which is highly adaptable, cold-resistant and tolerant of poor soil, as the tree species for ecological protection and landscape shaping; the herb plants selected are oats, Kentucky bluegrass, alfalfa and awnless bromegrass to form a multi-grass mixed sowing community. The spruce planting density was 2m×2m, with approximately 40 trees planted in each plot to ensure the stability of the tree community. The mixed sowing ratio of herbaceous plants was oat: Kentucky bluegrass: alfalfa: awnless bromegrass = 3:3:2:2, with oat as the pioneer grass and Kentucky bluegrass as the community-building grass. The sowing rate was 20kg / hm². Oat, as an annual herbaceous plant, can quickly emerge and grow to cover the ground surface, using its extensive root system to fix the soil, prevent soil erosion, and protect the growth of other grass species. Its litter can increase soil organic matter. Kentucky bluegrass, alfalfa, and awnless bromegrass are perennial herbaceous plants with strong slope protection and soil stabilization capabilities. Their leaves and stems can slow down the formation of rainwater runoff, and even after runoff occurs, they can reduce the erosive energy of the slope soil, thereby ensuring the long-term stability of the slope ecosystem.

[0042] Grass species mixed-species restoration area (2400~2650m): A multi-species mixed-species sowing model is adopted, selecting cold-resistant, drought-resistant, barren-tolerant, and wind-resistant herbaceous plants, mainly including *Leymus chinensis*, *Festuca sinensis*, *Poa chinensis*, and alfalfa. The mixed-species ratio is *Leymus chinensis*: *Festuca sinensis*: *Poa chinensis*: alfalfa = 4:3:2:1, and the sowing rate is 18 kg / hm². *Leymus chinensis* and *Festuca sinensis* are native herbaceous plants of the Gannan Plateau, with strong adaptability, and are preferred grass species for vegetation restoration in high-altitude areas. They can also be used as forage for cattle and sheep. *Poa chinensis* and alfalfa can improve the diversity and coverage of herbaceous plant communities. The nitrogen-fixing function of alfalfa can release nitrogen into the soil and improve soil fertility. While constructing artificial grasslands, a high-quality pasture landscape is formed, which is in harmony with the surrounding grassland landscape.

[0043] Natural Restoration Zone: Due to the steepness of the slope, artificial measures are difficult to take. Therefore, under the premise of ensuring safety, natural restoration is the main approach. Manual removal of dangerous rocks and debris from the slope is carried out to ensure slope stability. At the same time, protective fences are set up for the entire ecological restoration zone to reduce human interference and promote the gradual formation of organic matter suitable for the growth of some plants on the rock surface. As native plants naturally germinate and grow, a natural and original cliff landscape is formed, which contrasts sharply with the artificially restored area and enhances the diversity of the mining area landscape.

[0044] The excavation process of fish-scale pits specifically includes: laying out and positioning lines on the stepped slope surface of the mixed forest and grassland restoration area; excavating fish-scale pits of a specified size in a triangular arrangement and with a preset pit spacing; setting a preset angle of inclination at the bottom of the fish-scale pits and laying capillary trenches, and filling them with a mixture of topsoil and decomposed organic fertilizer in a preset proportion.

[0045] Specifically, see Figure 8 In the mixed forest-grassland restoration area, the fish-scale pit planting technique is used. This technique not only improves the survival rate of trees but also helps to retain rainwater and prevent soil erosion, while achieving a visually appealing effect of layered landscape and harmonious spatial layout. The fish-scale pits are excavated with dimensions of 1.0m long, 0.8m wide, and 0.6m deep, spaced 2m x 2m apart in a triangular pattern. The pits are filled with a mixture of topsoil and well-rotted organic fertilizer to improve soil fertility. Native spruce seedlings with a height of 1.1m-1.5m are selected for planting to enhance the survival rate of trees. Grass seeds are sown around the fish-scale pits to form a three-dimensional tree-grass protection system, achieving synergy between ecological protection and landscape optimization.

[0046] S104: Through the integration of terraced landscapes with tree and grass landscapes, pasture landscapes, and natural cliff landscapes, the ecological and landscape restoration of high-altitude open-pit limestone mining areas can be achieved.

[0047] Optionally, cultural slogans can be placed in prominent locations in the restoration area; through differentiated technical measures such as leveling slag heaps, planting mixed trees and grasses, and sowing mixed grass seeds, stepped slopes, mixed forest and grass areas and grassland areas can be formed to create a multi-layered landscape system; the high and steep cliffs formed by mining can be preserved and the dangerous rocks can be cleared and used as historical relics of the mining area.

[0048] Specifically, considering the mining area's proximity to the main road leading to attractions in Gannan such as Labrang Monastery, and its location within the Daxia River Basin ecological corridor construction area, the concept of landscape reconstruction was integrated throughout the entire ecological restoration process, including scheme design, engineering implementation, tree and grass planting, and post-construction maintenance. Following the principles of "ecological priority, landscape coordination, and cultural tourism integration," a landscape reconstruction model of "cultural leadership + ecological restoration + historical display of the mining area" was constructed. Cultural slogans guide the way: Set up cultural slogans in prominent locations, integrate the concept of ecological protection, enhance the cultural connotation of the mining area, and guide the public to establish ecological protection awareness.

[0049] Landscape layer optimization: Through differentiated technical measures such as leveling slag heaps, mixed planting of trees and grasses, and mixed sowing of grass seeds, stepped slopes, mixed forest and grass areas and grassland areas are formed, creating a multi-layered landscape system of "terraced landscape + tree and grass landscape + pasture landscape + natural cliff landscape", which is well connected with the adjacent Daxia River valley.

[0050] Historical display of the mining area: The exposed high and steep cliffs formed by mining are preserved and the dangerous rocks are cleared away to serve as historical relics and landscapes of the mining area. Combined with artificially restored vegetation and cultural slogans, the ecological evolution process of the mining area from "mining-destruction-restoration" is displayed, so as to achieve the synergy between ecological restoration and cultural inheritance.

[0051] To verify the effectiveness of the restoration technology, a standardized quadrat survey method was used to monitor the restoration results. The quadrat layout followed the principles of "representativeness, comparability, and repeatability." Each monitoring quadrat was rectangular, with an area of ​​110 m² (10 m × 11 m). This size was determined based on the fragmented topography of the mining area and statistical requirements, facilitating uniform sampling and data processing. Quadrats were selected from areas within the restoration zone with poor results, specifically those with larger slope angles and longer inclinations. This was intended to test the effectiveness of the ecological-landscape collaborative restoration technology under extremely unfavorable conditions, thereby enhancing the representativeness of the monitoring data. Four monitoring quadrats were evenly distributed within the restoration area. Quadrats 1–3 (YF-01, YF-02, YF-03) were located in the artificial restoration area, and quadrat 4 (YF-04) was located in the native vegetation area as a control. To ensure the scientific validity of the comparison, control plot 4 maintained the same basic conditions as the artificial remediation area in terms of altitude (2350–2400m), terrain slope (<25°), and soil type, avoiding data deviations due to environmental differences. The plot layout was combined with the distribution of the mining area remediation zones, covering areas with poor visual remediation effects to ensure spatial representativeness. The specific layout is as follows: Figure 9As shown in the figure, the field quadrat survey investigated vegetation growth indicators such as survival rate, average tree height, and vegetation coverage, as well as the landscape optimization effect.

[0052] In terms of monitoring methods, a combination of field sampling and laboratory testing was adopted. Standardized methods were used for soil sampling, employing tools such as shovels, wooden shovels, and ring cutters. The sampling depth was uniformly 0–20 cm, and three replicate samples were taken from each quadrat to reduce error. The sampling process is as follows: Figure 10 As shown, ensure operational consistency and data accuracy. After sample collection, send samples to the laboratory for natural air drying (temperature 25°C, avoid direct sunlight), remove stones and roots, pass through a 2mm sieve, and test soil organic matter, total nitrogen, pH, and other physicochemical indicators. See Table 4 for the quadrat collection table.

[0053] Table 4. Statistical Table of Sample Plot Information Effectiveness of Soil Physicochemical Property Improvement: Soil sampling and monitoring results showed that the pH values ​​of the soil in the artificial remediation area (YF-01-YF-03) and the original landform area (YF-04) were similar. Although there were still differences in soil organic matter and total nitrogen content, the soil physicochemical properties were effectively improved after 3 years of remediation (Table 5). The organic matter content of the soil in the artificial remediation area ranged from 19 to 23.1 g / kg, and the total nitrogen content ranged from 1.31 to 1.67 g / kg, both lower than those of the original soil (organic matter 57.7 g / kg, total nitrogen 4.84 g / kg), but significantly higher than before remediation. This is mainly because soil formation is slow in high-altitude areas, the remediation cycle is long, and improving soil fertility is a gradual and slow process. However, the soil in the artificial remediation area had a high gravel content (35%~45%), was loose, and had good aeration. Through topsoil covering, application of local decomposed organic fertilizer, and decomposition of herbaceous plant litter, soil fertility is gradually improving, providing a good foundation for long-term vegetation growth.

[0054] Table 5 Soil sample test results Monitoring results show that the vegetation in the artificially restored area is growing well, achieving the goal of rapid greening, and its growth status is stable (Table 6). The average survival rate of spruce planted in the mixed forest-grassland restoration area reached 94% (37-38 trees / 40 trees), with an average tree height of 156cm (152-162cm). The plants are growing healthily, indicating that the locally cultivated spruce can adapt to the growth environment of the mining area. In the mixed tree-grassland planting model, the trees and herbaceous plants are coupled and mutually promote each other's growth, which can effectively improve the survival rate of trees. The total vegetation coverage in the artificially restored area reached 82%-83%, which is lower than that in the original landform area (93%), but it is significantly improved compared with before restoration, effectively curbing soil erosion and improving the ecological environment of the mining area.

[0055] Table 6 Monitoring Results of Vegetation Growth Indicators However, during the monitoring, it was found that the fish-scale pits were washed and filled, and there was less soil in the pits, which affected the rainwater interception and vegetation water supply. It was necessary to optimize the restoration measures for the fish-scale pits. Small water retaining ridges could be set at the edge of the pits, the silt in the pits could be regularly cleaned, and additional soil could be supplemented to enhance the rainwater interception and moisture retention function of the fish-scale pits, providing sufficient water for vegetation growth. At the same time, overflow outlets could be set to drain excess water in a timely manner.

[0056] Landscape Optimization Effect: After 3 years of post-maintenance management, the landscape of the mining area has been significantly optimized, achieving the coordination of ecological restoration and landscape reconstruction ( Figure 11 ). By constructing stepped slopes, building anti-inclined platforms, and configuring different plants, the ecological restoration of the mining area has formed a landscape system that integrates local culture, nature, and tourism needs. The artificially restored area is naturally connected with the surrounding grasslands and the landscape of the Daxia River Valley, meeting the construction requirements of the Daxia River ecological corridor and the tourism experience needs of the Tumenguan - Labrang Monastery - Sangke Grassland, and significantly improving the landscape coordination. The retention of cultural slogans and the historical cliff bodies in the mining area has enriched the cultural connotation of the mining area landscape, realizing the initial practice of ecological protection and cultural tourism integration, providing support for the ecological restoration and cultural tourism integration development of local mining areas. After the restoration of the mining area, there is no obvious soil erosion phenomenon, the visual perception quality of the landscape has been improved, and the restoration effect has been significantly improved, changing from the original rock exposure and fragmented landscape to an ecological mining area with vegetation coverage and beautiful landscape.

[0057] To quantitatively evaluate the coordination degree between the restored area and the surrounding natural landscape, the Landscape Coordination Index (LCI) was used for evaluation. This index is based on the analysis of the similarity in hue and texture between the restored area and the natural reference area in the RGB bands of UAV images. The calculation formula is as follows:

[0058] ; where: R, G, B are the average RGB values of the restored area and the natural area, and the calculated result LCI = 0.93.

[0059] Classification of Coordination Degree: Excellent (LCI > 0.85): The landscape coordination is extremely good, and it is difficult to distinguish the restored area from the natural area visually; Good (0.75 < LCI ≤ 0.85): The coordination is good, with slight differences but not affecting the overall visual effect; General (0.60 < LCI ≤ 0.75): The coordination is general, with obvious visual differences; Poor (LCI ≤ 0.60): The coordination is poor, and the visual effect is unnatural.

[0060] The calculation results show that the restored area has excellent landscape harmony with the natural reference area. Furthermore, the LCI calculation results were verified by field quadrat surveys and visual assessments. The vegetation coverage of the restored area (82%-83%) is close to that of the natural area (93%). The restored stepped slopes form a good transition with the surrounding natural terrain, enhancing the overall landscape harmony.

[0061] The integrated ecological-landscape synergistic restoration system, encompassing engineering measures, vegetation configuration, and landscape regeneration, was developed for the Maweishan Mine in Gannan. This system is well-suited to the geographical characteristics of high-altitude open-pit limestone mines in the Gannan Plateau, addressing issues such as low vegetation survival rates, poor landscape coordination, and ineffective soil erosion control in local mining area restoration. Its core principles are "zoning differentiation" and "synergy." First, the differentiated restoration approach is adapted to the regional characteristics of the Gannan Plateau, especially the mining area's proximity to river valleys, strong winds year-round, and frequent short-term heavy rainfall. Based on the significant elevation differences and land suitability assessment results, different restoration zones are divided, and targeted plant configurations and engineering measures are adopted. The impact of climate, soil, wind, and rainfall factors in high-altitude areas on the restoration effect is fully considered, enhancing the relevance and feasibility of the restoration technology. In low-altitude areas, a mixed planting pattern of trees and grasses balances ecological protection and landscape effects, while in high-altitude areas, a mixed sowing pattern of grass species achieves rapid soil stabilization and stable plant community construction. In the natural restoration zone, slope safety is ensured after clearing dangerous rocks, minimizing human interference and maintaining the existing morphology, forming a synergistic model of "artificial restoration + natural restoration," which aligns with the concept of "site-specific and zoned restoration" in existing research.

[0062] Secondly, the coordinated promotion of ecological restoration and landscape reconstruction breaks through the limitations of traditional mining area restoration that "emphasizes ecology but neglects landscape". Landscape reconstruction is integrated into the entire restoration process. By constructing stepped slopes, adapting to different plants, and setting up cultural slogans, the ecological function, landscape effect, and inheritance of ethnic culture are simultaneously improved. This is in line with the "ecological-landscape integration" concept in advanced foreign restoration ideas. At the same time, it combines the local needs for cultural and tourism integration and development, thereby improving the comprehensive benefits of restoration.

[0063] Third, plant adaptation and engineering measures are coordinated. Native herbaceous plants and adaptable trees from the Gannan Plateau are selected to improve the survival rate and stability of vegetation. At the same time, engineering measures such as constructing retaining walls, planting trees in fish-scale pits, and building terraced fields effectively curb soil erosion and provide basic conditions for vegetation growth, forming a virtuous cycle of "engineering protects the ecology and ecology promotes the landscape".

[0064] The innovations of this paper lie in addressing the poor ecological restoration effectiveness of high-altitude open-pit limestone mines. Taking into full account the local geographical characteristics of high altitude, cold and humid climate, infertile soil, strong winds, and frequent short-duration heavy rainfall, this study prioritizes suitable local vegetation species that are beneficial for soil stabilization, landscape creation, and edible forage. It also selects engineering measures that help stabilize soil and reduce water and soil erosion, thus overcoming the limitations of existing technologies. The constructed ecological-landscape synergistic restoration system combines ecological restoration, landscape optimization, and cultural tourism integration, enhancing the overall benefits of restoration and providing a technical reference for the restoration of similar high-altitude mining areas. Compared with existing research on high-altitude mining area restoration, the innovations of this study are reflected in the following three aspects:

[0065] Site-specific optimization of stepped slope parameters: While the stepped restoration method in high-altitude meadow areas employs a double-layered rhomboid three-dimensional mesh to cover the slope, the synergistic design parameters for slope gradient and elevation were not clearly defined. This study, based on the characteristics of frequent short-duration heavy rainfall and severe soil erosion in the Gannan Plateau, quantitatively designed stepped slope parameters: the slope gradient was strictly controlled between 20° and 25°, the elevation was uniformly 6m, and the platform inclination angle was 2°–5°. Through mechanical stability and hydrological calculations, it was verified that this method can reduce runoff energy, improve erosion resistance efficiency by approximately 30% compared to the interception mesh scheme in the stepped restoration method for high-altitude meadow areas, and also create a terraced landscape.

[0066] Mechanical stability verification: The mechanical stability verification aims to ensure the long-term safety of the stepped slope under the cold, humid, and short-duration heavy rainfall conditions of the Gannan Plateau. The verification uses the limit equilibrium method (based on the Bishop simplified method) to calculate the slope safety factor.

[0067] The formula for calculating the slope safety factor (FS) is: ; in: c' The effective cohesion of the soil (kPa); ' The effective internal friction angle of the soil (°); The weight per unit width of the landslide body (kN / m) is calculated based on a slope height of 6m and a slope angle of 25°. Let be the arc length of the sliding surface (m). L=H / sinβ . Pore ​​water pressure (kPa); Let c′ be the inclination angle of the sliding surface (°). Take c′ = 5 kPa. ϕ ′=30°, soil bulk density γ =18kN / m3, slope height H=6m, slope α =25°, β =20°, considering short-term heavy rainfall, assuming the groundwater level rises to 1 / 3 of the slope height, take... u =0.3 γw H ,in γw The specific weight of water is 10 kN / m3. H Let's say it's the slope height. Substituting the data, we get... FS <1 indicates that the natural slope is unstable and requires engineering reinforcement.

[0068] Engineering measures to correct slope safety factor : ; To design the anti-sliding force of the retaining wall, based on a wall height of 3.5m and masonry friction design, a value of 50kN / m is adopted. The load is distributed through a counter-tilt platform (2°–5°). FS Upgraded to 1.5 to meet stability requirements.

[0069] Formula calculations show that natural slopes FS <1, but through stepped layout and retaining wall engineering, the slope gradient was reduced to 25°. FS The elevation was increased to a safe range, ensuring anti-slip and anti-overturning stability.

[0070] Hydrological calculation verification: The SCS curve number method was used to calculate the runoff, and the drainage channel design was verified in conjunction with the Manning formula.

[0071] SCS method flow rate formula: ; in, Q Runoff volume (mm); P (Rainfall amount (mm), taking a 10-year return period rainfall P = 50 mm / hour). S Potential water storage capacity (mm). for , CN The curve number is (soil type is sandy soil and gravelly soil, CN = 80, which is a well-drained soil).

[0072] Drainage verification: Manning's formula for calculating channel flow: ; in, V Flow velocity (m / s); N: roughness (n = 0.025 for earthen canals); R The hydraulic radius (m); S The slope of the canal bottom (average platform inclination angle 3.5°).

[0073] Calculations show that the runoff under short-term heavy rainfall is 13.7 mm. The stepped anti-dip platform can intercept a large amount of runoff. The Manning formula verifies that the drainage canal has sufficient capacity and can achieve multiple functions such as rainwater collection, vegetation nourishment and soil erosion control.

[0074] Suitable Plant Mixing Ratio and Configuration: Studies on the management period of high-altitude and cold mining areas emphasize replanting techniques, but do not optimize grass species combinations for high-wind areas; the ecological restoration scheme of Fushun West Open-pit Mine focuses on the selection of native plants, but lacks empirical evidence on the mixing ratio. This study proposes the following plant configuration for elevation zones: In the mixed forest-grass planting area (2350–2400m): the planting density of spruce is optimized to 2m×2m (survival rate 94%), and the grass species mixing ratio is (oat: Kentucky bluegrass: alfalfa: awnless brome = 3:3:2:2), where oat is the pioneer species and Kentucky bluegrass is the community-building species, with strong soil-fixing ability. Through wind resistance tests, the coverage is increased by 25% compared with a single grass species.

[0075] Mixed grass seeding area (2400–2650m): The mixed seeding ratio (Leymus chinensis:Festuca sinensis:Poa chinensis:Alfalfa = 4:3:2:1) was optimized for high wind environments, and the root interweaving density was increased by 40% compared with the "seven-step" grass planting technology and slope pit replanting technology used in the ecological restoration of the Muli mining area in Qinghai. Mixed grass seeding effectively solved the problem of "trees falling over due to high winds", achieving a unity of plant community resilience and landscape diversity.

[0076] Specifically, considering the mining area's proximity to the main road leading to attractions in Gannan such as Labrang Monastery, and its location within the Daxia River Basin ecological corridor construction area, the concept of landscape reconstruction was integrated throughout the entire ecological restoration process, including scheme design, engineering implementation, tree and grass planting, and post-construction maintenance. Following the principles of "ecological priority, landscape coordination, and cultural tourism integration," a landscape reconstruction model of "cultural leadership + ecological restoration + historical display of the mining area" was constructed. Cultural slogans guide the way: Set up cultural slogans in prominent locations, integrate the concept of ecological protection, enhance the cultural connotation of the mining area, and guide the public to establish ecological protection awareness.

[0077] This paper takes open-pit limestone mines as the research object, and addresses the key challenges in the restoration of open-pit limestone mines in ecologically fragile high-altitude areas. It conducts practical research on ecological-landscape collaborative restoration techniques, and through field monitoring and effectiveness analysis, draws the following conclusions: This embodiment constructs a three-pronged synergistic restoration system integrating "engineering measures, vegetation configuration, and landscape regeneration," adapted to the high-altitude, cold, humid, and infertile soil characteristics of the Gannan Plateau. Based on land suitability assessment results, the restoration area is divided into mixed forest-grassland planting areas, mixed grass seeding areas, and natural restoration areas, with differentiated ecological restoration models adopted for each zone. Practice shows that this system not only effectively improves vegetation survival rate and coverage but also achieves synergistic optimization of ecological functions and landscape effects, providing a referable technical paradigm for ecological restoration in high-altitude mining areas.

[0078] The research findings have direct application value for the construction of an ecological barrier in the upper reaches of the Yellow River: through engineering measures such as stepped slopes, planting trees in fish-scale pits, and constructing retaining walls, the soil erosion caused by short-term heavy rainfall has been effectively curbed, the regional water conservation capacity has been enhanced, and the ecological security of the upper reaches of the Yellow River has been maintained. After restoration, the vegetation coverage reached 82%–83%, and the soil physical and chemical properties continued to improve, confirming the effectiveness of the technical system in enhancing ecological stability.

[0079] Based on the topography and landforms left by mining, the land leveling follows the principle of "adapting to local conditions and coordinating with the landscape". By constructing an anti-sloping platform, maintaining an anti-sloping angle of 2° to 5°, the slope is kept between 20° and 25° and the slope height is about 6m. At the same time, multiple small non-concrete drainage ditches are constructed to discharge excess rainwater overflow into natural ditches, which can achieve multiple goals such as automatic rainwater collection, vegetation nutrient supply and slope soil erosion control.

[0080] In terms of the integrated development of culture and tourism on the plateau, landscape reconstruction techniques such as constructing cultural slogans, preserving historical cliffs, and building a multi-layered, terraced landscape system have been used to create a good connection between the restored mining area and the surrounding natural and cultural environment. This has provided support for the construction of the Daxia River ecological corridor and the Labrang Monastery tourism loop, not only improving the visual quality of the landscape but also providing a model for local ecotourism development, resulting in significant socio-economic benefits.

[0081] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A method for the coordinated restoration of ecology and landscape in high-altitude open-pit limestone mining areas, characterized in that, include: The high-altitude open-pit limestone mining area is divided into forest-grass mixed planting restoration area, grass mixed seeding restoration area and natural restoration area according to the elevation value and slope. In the mixed forest and grassland restoration area and the mixed grass seeding restoration area, platforms are constructed along the topographic contour lines, and the slope of the platforms is adjusted to a preset angle range to form stepped slopes. In the mixed forest-grassland restoration area, fish-scale pits arranged in a triangular pattern are excavated on the stepped slopes. Trees are planted on the stepped slopes and in the fish-scale pits, and annual and perennial grasses are mixed and sown on the stepped slopes to obtain a three-dimensional tree-grass configuration structure, forming a terraced landscape and a tree-grass landscape. In the grass seed mixed-sowing restoration area, various herbaceous plants are mixed and sown on the stepped slopes to obtain herbaceous plant communities, forming a pasture landscape. Natural cliff landscapes are formed in the natural restoration area. By combining terraced landscapes with tree and grass landscapes, pasture landscapes, and natural cliff landscapes, the ecology and landscape of high-altitude open-pit limestone mining areas can be restored in a coordinated manner.

2. The method for synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas as described in claim 1, characterized in that, The elevation of the mixed forest and grassland restoration area is 2350m to 2400m, the elevation of the mixed grass seed restoration area is 2400m to 2650m, and the natural restoration area is an area with an altitude of 2400m or above and a slope of ≥70°.

3. The method for synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas as described in claim 1, characterized in that, The anti-tilt angle of the platform ranges from 2° to 5°; the slope adjustment angle of the platform ranges from 20° to 25°.

4. The method for synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas as described in claim 1, characterized in that, After the formation of the stepped slope, the following is also included: A retaining wall is constructed at the bottom of the stepped slope, including: Remove loose rocks and obstacles from the bottom working area of ​​the stepped slope, excavate the foundation pit to the bedrock, control the depth and bottom width of the foundation pit, lay a mortar cushion layer of specified thickness and compact the base. The wall is constructed using dry-laid blocks of 30cm or more in layers, with expansion joints set at specified intervals and filled with asphalt-impregnated hemp rope. A sand and gravel filter layer is backfilled on the back of the wall.

5. A method for the coordinated restoration of ecology and landscape in a high-altitude open-pit limestone mining area as described in claim 1, characterized in that, The excavation process of the fish-scale pit specifically includes: Layout and positioning are carried out on the stepped slope surface of the mixed forest and grassland restoration area; Excavate fish-scale pits of a specified size according to the triangular arrangement and the preset pit spacing; Set a preset angle of inclination at the bottom of the fish-scale pit and lay capillary trenches, then fill it with a mixture of topsoil and decomposed organic fertilizer in a preset ratio.

6. The method for synergistic restoration of ecology and landscape in high-altitude open-pit limestone mining areas as described in claim 1, characterized in that, In the forest-grass mixed planting restoration area, the annual grass species is oat, and the perennial grass species are Kentucky bluegrass, alfalfa and awnless bromegrass, with a mixed planting ratio of oat:Kentucky bluegrass:alfalfa:awnless bromegrass = 3:3:2:

2. In the mixed grass species remediation area, the mixed grass species include: crested wheatgrass, Chinese fescue, Kentucky bluegrass, and alfalfa, with a mixed ratio of crested wheatgrass: Chinese fescue: Kentucky bluegrass: alfalfa = 4:3:2:

1.

7. A method for the coordinated restoration of ecology and landscape in a high-altitude open-pit limestone mining area as described in claim 1, characterized in that, The formation process of the stepped slope also includes: Maintain a counter-slope angle of 2° to 5° during slope construction to allow the platform to collect rainwater on its own; Multiple non-concrete drainage channels were constructed according to the principle of decentralized drainage to discharge excess rainwater overflow into natural ditches.

8. A method for the coordinated restoration of ecology and landscape in a high-altitude open-pit limestone mining area as described in claim 1, characterized in that, The method also includes a quantitative assessment of the harmony of the restored landscape, specifically including: The landscape harmony index is used to assess the degree of harmony between the restoration area and the surrounding natural landscape. This landscape harmony index is based on RGB band analysis of UAV imagery, and the formula is: ； In the formula, As a landscape harmony index, , and These are the average RGB values ​​of the repaired area. , and These are the average RGB values ​​of the surrounding natural reference area; When LCI > 0.85, it is considered excellent coordination; when LCI ≤ 0.75, it is considered good coordination.

9. A method for the coordinated restoration of ecology and landscape in a high-altitude open-pit limestone mining area as described in claim 1, characterized in that, The slope safety of the stepped slope was verified using the limit equilibrium method, with the following formula: ； In the formula, For the slope safety factor, For effective soil cohesion, The effective internal friction angle of the soil, This refers to the weight per unit width of the landslide mass. Let the arc length of the sliding surface be , Pore ​​water pressure, The inclination angle of the sliding surface. Design anti-sliding force for retaining walls; when When the time is right, it indicates that the stepped slope meets the safety requirements.

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