Method for ecological restoration of mine slope vegetation holes by using fine-grained iron tailings

Abstract

The invention discloses a method for ecologically restoring plant-growing holes of a mine slope by using fine-grained iron tailings, which comprises the following steps of: firstly, designing and constructing the plant-growing holes, and then preparing a soil matrix which comprises the following components in percentage by weight: 30-60% of fine-grained iron tailings, 10-30% of stope weathered soil, 5-20% of mining fly ash, 15-35% of native soil and the balance of organic fertilizer to form a mixture 1; adding plant seeds and mixing to form a mixture 2; and mixing the mixture 2 with the water-retaining agent to form a mixture 3. And planting the mixture 3 into the planting holes, and then performing watering maintenance. The fine-grained iron tailing soil matrix prepared by the invention takes the fine-grained iron tailings in the mining area as a main raw material, is used for ecological restoration of the rock slope of the mining area stope, and is maintained for 60 days, so that the plant germination rate is high, the arbor / shrub germination rate reaches 85% or above, and the herbal and climbing plant germination rate reaches 90%, the bulk consumption of the fine-grained iron tailings is realized, and the ecological restoration of the rock slope of the mining area stope is realized. And low-cost ecological restoration of the rock slope of the open stope in the mining area is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological restoration of open-pit mine slopes, and particularly relates to a low-cost ecological restoration of rock slopes in open-pit mines using fine-grained iron tailings to prepare soil substrates. BACKGROUND

[0002] Mine resources are related to the sustainable development of society, but with large-scale mining of mine resources, it will have a serious impact on the regional ecological environment, not only causing changes in the topography and geomorphology of the mining area, but also causing geological disasters such as mudslides and landslides, which pose a serious threat to the safety of mining personnel and surrounding residents. The stability of the mine slope is one of the factors that induce geological disasters, and due to the influence of factors such as the structure of the mine geology rock mass, the structure of the mine geology rock mass, and the external environment, the stability of the slope will be affected, and serious geological disasters are likely to occur.

[0003] In addition, after a large amount of mine resources are mined, a large amount of tailings, mining stripped soil, and waste mine pits are left behind, causing large areas of rock to be exposed. These direct and exposed "scars" cause soil erosion and safety hazards, and damage the ecological environment. In some areas, mining also leads to environmental pollution, ground subsidence, rock layer landslides, and mudslides, among other geological environmental problems. Due to the large area occupied, lack of backfill and reclamation soil sources, and high ecological restoration treatment investment, the ecological restoration of mining land is slow to advance. How to effectively use large amounts of fine-grained iron tailings to prepare soil substrates for ecological restoration of mine slopes has become a hot and difficult point of research at home and abroad.

[0004] Patent application No. 202210081089.3 discloses a high-cold high-steep mine slope ecological restoration substrate, which includes a structural layer substrate and a surface layer substrate. The substrate structural layer includes ceramsite and walnut shell particles, husks and straw joints, EPS particles, soil conditioner PAM, and water retaining agent. The surface layer of the substrate includes straw fibers, husks, EPS particles, soil conditioner PAM, and water retaining agent. However, this mine slope ecological restoration substrate mainly uses plant materials, which is limited by the source of raw materials and the cost of use, and is difficult to be used on a large scale in open-pit mine slope restoration projects.

[0005] Chinese patent application 202410034578.2 discloses a method for ecological restoration of mine slope, mainly by using slope hanging net guest soil spray seeding technology, combined with anti-skid slow-release ecological bag installation, not only can increase the friction to prevent the slope guest soil from sliding, but also can provide long-term nutrients and water for plant growth; at the same time, the method of combining the guest soil bottom spray substrate and the surface spray substrate developed by the invention, combined with soil repair plant seed mixed planting spray seeding technology, makes the heavy metal pollution in the mine soil be relieved. But the construction process of this method is relatively complex, the cost of slope hanging net is high, and a large amount of guest soil resources is consumed.

[0006] Patent application No. 201810064692.4 "a method for resource utilization of iron tailings", uses soil conditioner made of crop straw to mix with iron tailings and dry manure after fermentation, to make tailings soil, solves the problems of crop straw treatment and iron tailings disposal, but the treatment period is long, and crop straw is needed to prepare the conditioner.

[0007] The present application uses fine-grained iron tailings as the main raw material to prepare soil matrix for ecological restoration of rock slope in mine stope, realizes efficient ecological utilization of iron tailings, replaces a large amount of earthwork, and fully utilizes the water produced in the process of fine-grained iron tailings in the process of spray seeding, saves water in the process of utilization of fine-grained iron tailings and water supplement in the process of ecological restoration of soil matrix, realizes on-site application, saves time and space, and realizes on-site application. SUMMARY

[0008] The purpose of the present application is to provide a method for ecological restoration of mine slope planting hole using fine-grained iron tailings, which has low production cost, widely available raw materials, easy on-site preparation and significant ecological restoration effect, and provides a new way for large-scale reduction of iron tailings.

[0009] To achieve the above purpose of the present application, a method for ecological restoration of mine slope planting hole using fine-grained iron tailings is adopted, which uses the following process and steps:

[0010] S1, the stability of the mine open slope rock mass is surveyed, evaluated, the parameters of the mine open slope planting hole are designed, and the planting hole is constructed; the planting hole is arranged according to the plum blossom type or the square type.

[0011] S2. Weigh and mix the raw materials of the soil matrix according to the following dry weight percentages: 30-60% fine-grained iron tailings, 10-30% weathered soil from the mining area, 5-20% mining dust, and 15-35% native soil; the fine-grained iron tailings are iron-bearing tailings after iron ore beneficiation, wherein the content of -0.075mm particle size is ≥60%; the mining dust is the dust collected during the crushing process of iron ore in the mining area.

[0012] S3. Mix 3-6% of organic fertilizer by mass of soil matrix to form mixture 1; add 0.03-0.06% of tree / shrub, herb and / or climbing plant seeds by mass of soil matrix to mixture 1 to form mixture 2.

[0013] S4. Add 0.01-0.02% water-retaining agent (by total mass of soil matrix) to mixture 2 and mix to form mixture 3. The moisture content of mixture 3 is controlled at 10-20%. The moisture content of mixture 3 is adjusted by concentration before mixing fine iron tailings slurry with other soil matrix raw materials. Plant mixture 3 into the planting hole at a depth of 20-50cm.

[0014] S5. Water the slope of the mining area with planting holes and mixed material 3 for 50-70 days to maintain the soil moisture content at 10-20%.

[0015] Preferably, in step S1, the layout parameters of the planting holes are: hole diameter 80-120mm, hole...

[0016] The hole depth is 20-50cm, the hole spacing is 1-2m, and the inclination angle is 10-15°.

[0017] Preferably, in step S2, the fine-grained iron tailings have a pH range of 6-8, an effective sulfur component of less than 2.0%, and a moisture content of 30%-50%; the particle size of the weathered soil and native soil in the mining area is controlled below 5mm; the native soil is soil within 20 kilometers of the ecological restoration mining area, with an organic matter content of 20-80g / kg, a total nitrogen content of 40-200mg / kg, an available phosphorus content of 5-60mg / kg, and a available potassium content of 30-600mg / kg.

[0018] Preferably, in step S3, the organic fertilizer is composed of plant fiber, compound fertilizer and trace element additives in a ratio of (270-330):(2.3-2.8):1, the length of the plant microfiber is less than 15cm, the N:P:K ratio of the compound fertilizer is (1.7-2.2):(1.7-2.2):1, and the trace element additive is a boron-molybdenum-manganese compound, which is prepared by H3BO3, MoO3 and MnSO4·H2O in a ratio of (2.5-3.5):(0.8-1.2):(0.8-1.2).

[0019] Preferably, in the S3 step, the arbor / shrub is one, two or more of Ilex asprella, Cinnamomum camphora, Ailanthus altissima, Robinia pseudoacacia, Wisteria sinensis; the herb is one, two or more of Imperata cylindrica, Lactuca indica, Cymbopogon citratus, Setaria viridis, Eupatorium odoratum; and the vine is one, two or more of Pteria noli, Tetrastigma hemsleyanum, Scindapsus aureus and Buxus sinica.

[0020] Preferably, in the S4 step, the water-retaining agent is potassium-polyacrylic acid-polyacrylamide copolymer, and the water absorption ratio is not less than 400.

[0021] Compared with the prior art, the method for ecological restoration of a mine slope planting hole by using fine-grained iron tailings has the following beneficial effects after adopting the above technical scheme:

[0022] (1) The fine-grained iron tailings in the mining area are used as the main raw material, cooperated with other solid wastes in the mining area, and the other additives are widely distributed and less affected by the regional nature of the raw materials, so that the method has good implementability, can provide a new way for the ecological utilization of large quantities of iron tailings, and has significant economic, environmental and social benefits.

[0023] (2) The prepared fine-grained iron tailings soil matrix can be widely applied to the ecological restoration of the rock slope of the mining area, truly realizing the conversion of waste into benefit, and using local materials and applying locally, which not only saves the amount of natural soil, but also saves the time and space links.

[0024] (3) The fine-grained iron tailings soil matrix has simple preparation and application process and low cost, has good competitiveness, takes full advantage of the high water content of the fine-grained iron tailings slurry, and avoids the drying burden of the resource utilization of other fine-grained iron tailings.

[0025] (4) The application effect is remarkable. Through experimental research, when the prepared fine-grained iron tailings soil matrix is used for the ecological restoration of the rock slope of the mining area, the germination rate of arbor / shrub is more than 85% after 60 days of maintenance, and the germination rate of herb and vine is 90%. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a principle process flow chart of the method for ecological restoration of a mine slope planting hole by using fine-grained iron tailings.

[0027] Figure 2 The figure is an XRD curve of the fine-grained iron tailings used in the method.

[0028] Figure 3 The figure is a particle size distribution graph of the fine-grained iron tailings used in the method. DETAILED DESCRIPTION

[0029] To better describe the present invention, a method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes is described in further detail below with reference to the accompanying drawings. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as...

[0030] This invention limits the scope of the invention. Any simple modifications made based on the essence of the invention should be covered within the scope of protection of this invention.

[0031] Depend on Figure 2 The XRD curve of the fine-grained iron tailings used in the method of the present invention shows that the fine-grained iron tailings used in the examples are mainly composed of feldspar phase, quartz phase and other phases.

[0032] Depend on Figure 3 The particle size distribution diagram of the fine iron tailings used in the method of the present invention shows that 87% of the fine iron tailings have a particle size of -0.075 mm.

[0033] Depend on Figure 1 The flowchart illustrating the principle of the present invention's method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes shows that the present invention is implemented using the following process steps in the embodiments:

[0034] S1. Conduct surveys and assessments on the stability of the rock mass of the open-pit slope of the mine, design the parameters of the vegetation hole mesh for the open-pit slope of the mine, and carry out the construction of the vegetation holes; the layout parameters of the vegetation holes are: hole diameter 80-120mm, hole depth 20-50cm, hole spacing 1-2m, and inclination angle 10-15°.

[0035] S2. Weigh and mix the raw materials of the soil matrix according to the following dry weight percentages: 30-60% fine-grained iron tailings, 10-30% weathered soil from the mining area, 5-20% mining dust, and 15-35% native soil. The fine-grained iron tailings are iron-bearing tailings after iron ore beneficiation, with a -0.075mm particle size content ≥60%; the mining dust is dust collected during the iron ore crushing process in the mining area; the fine-grained iron tailings have a pH range of 6-8, an effective sulfur content of less than 2.0%, and a moisture content of 30%-50%; the particle size of the weathered soil and native soil is controlled below 5mm; the native soil is soil within 20 kilometers of the ecological restoration mining area, with an organic matter content of 20-80g / kg, a total nitrogen content of 40-200mg / kg, an available phosphorus content of 5-60mg / kg, and a available potassium content of 30-600mg / kg.

[0036] S3, the soil matrix is mixed with 3-6% of organic fertilizer outside the soil matrix to form a mixture 1; the mixture 1 is mixed with 0.03-0.06% of arbor / shrub, herb and / or vine seeds to form a mixture 2. The organic fertilizer is composed of plant fiber, compound fertilizer and trace element additive, the ratio of which is (270-330):(2.3-2.8):1, the length of the plant microfiber is less than 15 cm, the N:P:K ratio of the compound fertilizer is (1.7-2.2):(1.7-2.2):1, and the trace element additive is a boron-molybdenum-manganese compound agent, which is composed of H3BO3, MoO3 and MnSO4·H2O, the ratio of which is (2.5-3.5):(0.8-1.2):(0.8-1.2); the arbor / shrub is one, two or more of Ilex asprella, Cinnamomum camphora, Ailanthus triphysa, Robinia pseudoacacia and Wisteria sinensis; the herb is one, two or more of Imperata cylindra, Lactuca indica, Lemon grass, Setaria viridis and Eulaliopsis binata; and the vine is one, two or more of Pteria noli-tangere, Bauhinia championii, Monstera deliciosa and Hedera helix.

[0037] S4, the mixture 2 is mixed with 0.01-0.02% of water-retaining agent to form a mixture 3, the water content of the mixture 3 is controlled at 10-20%, and the water content of the mixture 3 is adjusted by the concentration of the fine-grained iron tailings slurry before mixing with other soil matrix raw materials; the mixture 3 is planted in the planting hole to a depth of 20-50 cm. The water-retaining agent is a potassium-polyacrylic acid-polyacrylamide copolymer, and the water absorption ratio is not less than 400.

[0038] S5, the stope slope provided with the planting hole and the mixture 3 is watered for 60 days to maintain the soil water content at 10-20%.

[0039] Example 1

[0040] S1, the stability of the mine open-pit slope rock mass is surveyed and evaluated, the planting hole mesh parameters of the mine open-pit slope are designed, and the planting hole construction is performed;

[0041] S2, the raw materials of the soil matrix are weighed and proportioned according to the following dry weight mass percentage: fine-grained iron tailings 60%, stope weathered soil 10%, mining dust removal ash 10% and virgin soil 20%;

[0042] S3, the soil matrix is mixed with 6% of organic fertilizer outside the soil matrix to form a mixture 1; the mixture 1 is mixed with 0.03% of Ilex asprella seeds to form a mixture 2;

[0043] S4. Add 0.02% water-retaining agent of the total mass of soil matrix to mixture 2 and mix to form mixture 3. The moisture content of mixture 3 is controlled at 15%. The moisture content of mixture 3 is adjusted by concentration before mixing fine iron tailings slurry with other soil matrix raw materials. Plant mixture 3 into the planting hole at a depth of 50cm.

[0044] S5. Spray the slope of the stope with planting holes and mixed material 3 for 60 days.

[0045] Water maintenance, keeping the soil moisture content at 15±2%.

[0046] Example 2

[0047] S1. Conduct surveys and assessments on the stability of the rock mass of the open-pit slope of the mine, design the parameters of the mesh for the vegetation holes on the open-pit slope of the mine, and carry out the construction of the vegetation holes.

[0048] S2. Weigh and mix the raw materials of the soil matrix according to the following dry weight percentages: 50% fine-grained iron tailings, 15% weathered soil from the mining area, 10% mining dust, and 25% native soil;

[0049] S3. Mix 5% organic fertilizer by mass of soil matrix to form mixture 1; add 0.06% kudzu seeds by mass of soil matrix to mixture 1 and mix to form mixture 2.

[0050] S4. Add 0.015% water-retaining agent (by total mass of soil matrix) to mixture 2 and mix to form mixture 3. The moisture content of mixture 3 is controlled at 12%. The moisture content of mixture 3 is adjusted by concentration before mixing fine iron tailings slurry with other soil matrix raw materials. Plant mixture 3 into the planting hole at a depth of 20cm.

[0051] S5. Spray the slope of the stope with planting holes and mixed material 3 for 60 days.

[0052] Water maintenance, keeping the soil moisture content at 12±2%.

[0053] The method of this invention has been applied in an ecological restoration and greening project on the slopes of a large open-pit mine in East China. Analysis of the plant germination rates showed that Examples 1 and 2 had germination rates of 88% and 98%, respectively, both demonstrating excellent ecological restoration effects.

Claims

1. A method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes, characterized in that... The following steps are to be taken: S1. Conduct surveys and assessments on the stability of the rock mass of the open-pit slope of the mine, design the parameters of the mesh for the vegetation holes on the open-pit slope of the mine, and carry out the construction of the vegetation holes; S2. Weigh and mix the raw materials of the soil matrix according to the following dry weight percentages: 30-60% fine-grained iron tailings, 10-30% weathered soil from the mining area, 5-20% mining dust, and 15-35% native soil; the fine-grained iron tailings are iron-bearing tailings after iron ore beneficiation, wherein the content of -0.075mm particle size is ≥60%; the mining dust is the dust collected during the crushing process of iron ore in the mining area. S3. Mix 3-6% of organic fertilizer by mass of soil matrix to form mixture 1; add 0.03-0.06% of tree / shrub, herb and / or climbing plant seeds by mass of soil matrix to mixture 1 to form mixture 2. S4. Add 0.01-0.02% water-retaining agent (by total mass of soil matrix) to mixture 2 and mix to form mixture 3. The moisture content of mixture 3 is controlled at 10-20%. The moisture content of mixture 3 is adjusted by concentration before mixing fine iron tailings slurry with other soil matrix raw materials. Plant mixture 3 into the planting hole at a depth of 20-50cm. S5. Water the slope of the mining area with planting holes and mixed material 3 for 50-70 days to maintain the soil moisture content at 10-20%.

2. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that... The layout parameters for the planting holes in step S1 are: hole diameter 80-120mm, hole depth 20-50cm, hole spacing 1-2m, and inclination angle 10-15°.

3. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that: In step S2, the fine-grained iron tailings have a pH range of 6-8, an effective sulfur component of less than 2.0%, and a moisture content of 30%-50%; the particle size of the weathered soil and native soil in the mining area is controlled below 5mm.

4. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that: In step S2, the native soil refers to the soil within 20 kilometers of the ecological restoration mining area, with an organic matter content of 20-80 g / kg, a total nitrogen content of 40-200 mg / kg, an available phosphorus content of 5-60 mg / kg, and a available potassium content of 30-600 mg / kg.

5. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that: In step S3, the organic fertilizer is composed of plant fiber, compound fertilizer and trace element additives in a ratio of (270-330):(2.3-2.8):

1. The length of the plant microfiber is less than 15cm. The N:P:K ratio of the compound fertilizer is (1.7-2.2):(1.7-2.2):

1. The trace element additive is a boron-molybdenum-manganese compound, which is prepared from H3BO3, MoO3 and MnSO4·H2O in a ratio of (2.5-3.5):(0.8-1.2):(0.8-1.2).

6. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that: In step S3, the trees / shrubs are one, two, or more of the following: horsethorn, camphor tree, ailanthus, black locust, and purple locust; the herbaceous plants are one, two, or more of the following: cogongrass, wild lettuce, lemongrass, foxtail grass, and horsetail; and the climbing plants are one, two, or more of the following: kudzu, kudzu vine, pothos, and ivy.

7. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 1, characterized in that: In step S4, the water-retaining agent is a potassium-polyacrylate-polyacrylamide copolymer with a water absorption ratio of not less than 400.

8. The method for ecological restoration of mine slopes using fine-grained iron tailings through vegetation holes as described in claim 2, characterized in that: In step S2, the fine-grained iron tailings have a pH range of 6-8, an effective sulfur content of less than 2.0%, and a moisture content of 30%-50%; the particle size of the weathered soil and native soil from the mining area is controlled below 5mm; the native soil refers to soil within 20 kilometers of the ecological restoration mining area, with an organic matter content of 20-80g / kg, a total nitrogen content of 40-200mg / kg, an available phosphorus content of 5-60mg / kg, and a available potassium content of 30-600mg / kg; in step S3, the organic fertilizer consists of plant fibers, compound fertilizer, and trace element additives in a ratio of (270-330):(2.3-2.8):1, with plant microfiber length less than 15cm, and the N:P:K ratio of the compound fertilizer being (1.7... -2.2):(1.7-2.2):1, the trace element additive is a boron-molybdenum-manganese composite agent, which is prepared from H3BO3, MoO3, and MnSO4·H2O in a ratio of (2.5-3.5):(0.8-1.2):(0.8-1.2); the tree / shrub is one, two or more of the following: horsethorn, camphor tree, ailanthus, black locust, and purple locust; the herbaceous plant is one, two or more of the following: white cogongrass, wild lettuce, lemongrass, foxtail grass, and horsetail; the climbing plant is one, two or more of the following: kudzu, moth kudzu, pothos, and ivy; in step S4, the water-retaining agent is a potassium-polyacrylate-polyacrylamide copolymer with a water absorption ratio of not less than 400.

9. A method for ecological restoration of mine slopes using fine-grained iron tailings via vegetation holes as described in claim 8, characterized in that: In step S1, the planting holes are arranged in a plum blossom or square pattern.

10. A method for ecological restoration of mine slopes using fine-grained iron tailings via vegetation holes as described in claim 9, characterized in that: The organic fertilizer contains plant fiber, compound fertilizer, and trace elements in a ratio of 500:2.5:1, and the compound fertilizer contains N:P:K in a ratio of 1.9:1.9:1.

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