A method for constructing a "sponge" mining area by using underground mining in a subsidence area

Abstract

This invention discloses a method for constructing a "sponge" mining area in the subsidence zone of underground mining. It fully utilizes the large surface subsidence space caused by mining operations to purify, store, and utilize mine water resources, and restore the mining area's ecology. The method involves horizontally dividing the subsidence space into "purification-storage-utilization" functional zones and vertically reconstructing the soil into "isolation-conservation-nurturing" functional zones. Horizontally, the surface subsidence basin is divided into three water resource functional zones: a water purification zone, a water storage zone, and a water use zone. The water purification zone is located upstream of the gravity flow of mine water at the edge of the subsidence basin; the water storage zone is located in the center of the subsidence basin; and the water use zone is located downstream. This method not only restores mine land resources but also achieves multiple objectives, including improving the water environment, conserving water resources, restoring the aquatic ecosystem, ensuring water security, and utilizing water resources.

Description

Technical Field

[0001] This invention relates to the field of land reclamation and ecological restoration technology. Specifically, it is a method for constructing a "sponge" mining area in a subsidence zone caused by underground mining. Background Technology

[0002] The western region is characterized by an arid climate, low vegetation cover, and severe water scarcity. With the westward shift of my country's coal resource development strategy, high-intensity underground mining in mining areas easily leads to the leakage of groundwater or surface water, which flows into the underground mining space. This not only exacerbates the water scarcity in the western region but also causes a large amount of water pollution. Some local governments restrict the discharge of mine water based on environmental protection requirements, which seriously damages the ecological environment of mining areas and restricts the sustainable development of mines. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a method for constructing a "sponge" mining area in the subsidence area of ​​underground mining, thereby improving the water environment, conserving water resources, restoring the water ecology, ensuring water security, and utilizing water resources.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] A method for constructing a "sponge" mining area by utilizing underground mining subsidence areas divides the surface subsidence basin of the mining area into three water resource functional zones in sequence: a water purification functional zone, a water storage functional zone, and a water use functional zone.

[0006] The water purification zone is located upstream of the water flow at the edge of the surface subsidence basin in the mining area, the water storage zone is located in the center of the surface subsidence basin in the mining area, and the water use zone is located downstream of the water flow in the surface subsidence basin in the mining area.

[0007] Water flows out of the mine shaft and enters the water purification zone. After undergoing sedimentation and preliminary ecological purification treatment in the water purification zone, it enters the water storage zone.

[0008] In the water storage area, the mine water is conserved and stored by reconstructing "sponge" soil.

[0009] The downstream water use zone will "release" and utilize the water stored in the water storage zone when needed or in excess, thereby promoting the utilization of mine water resources and ecological environmental protection.

[0010] The above-mentioned method for constructing a "sponge" mining area by utilizing the subsidence area of ​​underground mining involves laying a waterproof layer on the subsided surface of the water purification function zone, water storage function zone, and water use function zone.

[0011] The above-mentioned method for constructing a "sponge" mining area using underground mining subsidence areas has a water-resistant layer with a thickness of 0.2-0.5m, which is made of soil and fly ash through compaction. The water-resistant layer has a permeability coefficient of <0.1m / d and a compaction degree of 1200-1400KPa.

[0012] The above-mentioned method for constructing a "sponge" mining area by utilizing underground mining subsidence areas involves first stripping the surface soil of the subsidence basin in the mining area before laying the waterproof layer, and then grouting to treat the ground fissures caused by mining.

[0013] The above-mentioned method for constructing a "sponge" mining area using the subsidence area of ​​underground mining includes an artificial wetland in the water purification functional area (1), which includes a water storage layer and a soil layer from top to bottom; the soil layer is composed of soil stripped from the water-proof layer, broken rock mass and fly ash, and aquatic plants are planted on the soil layer.

[0014] In the above-mentioned method of constructing a "sponge" mining area by utilizing underground mining subsidence areas, the mass ratio of the soil stripped from the aquitard layer, the broken rock mass, and the fly ash is 4-5:1:2-3.

[0015] The above-mentioned method for constructing a "sponge" mining area by utilizing the subsidence area of ​​underground mining involves reconstructing a water-retaining layer and a nutrient-planting layer from top to bottom in the water storage functional area.

[0016] The above-mentioned method for constructing a "sponge" mining area using underground mining subsidence areas includes a water-holding layer composed of a mixture of plant fibers and sand and gravel, with plant fibers accounting for 15-25% of the mixture volume and sand and gravel accounting for 75-85% of the mixture volume; the water holding capacity of the water-holding layer is >100%, and the permeability coefficient is >10m / d; wherein the plant fibers are crop straw, cotton or hemp, with a particle size of less than or equal to 10mm; and the sand and gravel are one or more of coal gangue, river sand, and open-pit mine spoil, with a particle size of greater than or equal to 0.1mm.

[0017] The above-mentioned method for constructing a "sponge" mining area using underground mining subsidence areas includes a planting nutrient layer with a thickness of 0.3-0.5m. The planting nutrient layer is made by mixing soil with organic compost, humic acid and microbial agents. The mixed soil contains at least 1.5% organic matter. The soil is a water-resistant layer stripped soil. The organic compost is obtained by composting and fermenting agricultural and forestry waste, which includes one or more of livestock and poultry manure, edible fungus residue, chestnut shells and fallen leaves.

[0018] The above-mentioned method for constructing a "sponge" mining area by utilizing the subsidence area of ​​underground mining involves constructing hydraulic facilities, water purification plants, and surface drainage ditches and gates near the water use functional area.

[0019] The technical solution of the present invention achieves the following beneficial technical effects:

[0020] Addressing the dual challenges of water scarcity, water pollution, and limited discharge in western mining areas, this study fully utilizes the extensive surface subsidence spaces created by mining operations. With the aim of purifying and storing mine water, utilizing mine water resources, and restoring the mining area's ecology, the study conducts horizontal "purification-storage-utilization" functional zoning planning and vertical "isolation-conservation-nurturing" functional soil reconstruction research on the surface subsidence spaces. This aims to achieve multiple objectives in the mining areas, including improving the water environment, conserving water resources, restoring the water ecology, ensuring water security, and utilizing water resources.

[0021] Setting up an aquitard at the bottom of the surface subsidence basin throughout the mining area can prevent mine water held above from seeping downwards into underground aquifers or tunnel spaces, causing groundwater pollution and threatening mine production safety. The aquitard is made of compacted soil and fly ash. Fly ash is inexpensive and readily available. The aquitard effect is achieved by controlling the compaction degree and permeability coefficient.

[0022] The water-retaining layer of the water storage area is made of a mixture of plant fibers and sand, forming a porous "sponge" layer that can store a large amount of mine water resources and also conserve the ecosystem. The planting nutrient layer can be planted with pioneer plants according to the local ecological environment, which can improve the environment and further conserve water sources.

[0023] Water purification zone: Initial sedimentation treatment is carried out on the mine drainage. The broken rock mass near the mining area is mixed with soil and fly ash to filter and adsorb large suspended solids in the mine drainage. The oxides such as silica, alumina, and calcium oxide in the fly ash can also adsorb harmful ions in the mine water, further treating the mine water.

[0024] Water use functional zones: Based on the characteristics of downstream users' water use, hydraulic facilities, water purification plants, and surface drainage ditches and gates can be constructed to further treat the purified and conserved water sources, so that they can be effectively utilized after meeting the corresponding standards for agricultural water use, production water use, or domestic water use. Attached Figure Description

[0025] Figure 1 A schematic diagram of the structure of the "sponge" mining area of ​​this invention.

[0026] The labels in the attached diagram are as follows: 1-Water purification functional area; 2-Water storage functional area; 3-Water use functional area; 4-Mine; 5-Isolation layer; 6-Water retention layer; 7-Planting nutrient layer; 8-Cleanroom. Detailed Implementation

[0027] Select the surface subsidence space formed by mining operations to construct "sponge" mining areas.

[0028] On the horizontal plane distribution of the surface subsidence basin in the mining area, it is divided into three water resource functional zones: water purification functional zone 1, water storage functional zone 2, and water use functional zone 3; for example Figure 1 As shown.

[0029] Water purification zone 1: Located upstream of the mine water flow zone on the edge of the surface subsidence basin in the mining area, this zone experiences minimal surface subsidence. Mine water flows from the wellhead through this zone to the water storage zone. Artificial wetlands are constructed in this area to provide preliminary purification and treatment for the mine water.

[0030] Water Storage Function Zone 2: This zone is located in the central area of ​​a large subsidence zone, with significant and thorough surface subsidence. During the reclamation and leveling of the land in this area, by reconstructing the "sponge" structure of the soil profile, a large amount of storage space can be created to store mine water and provide moisture for plant growth, thereby achieving the purpose of conserving water resources and restoring the aquatic ecosystem.

[0031] Water use functional zone 3: Located in the downstream area of ​​the water flow in the surface subsidence basin of the mining area; hydraulic facilities, water purification plants, surface drainage ditches and gates are constructed near the water use functional zone to "release" and utilize the stored water when needed or in excess, so as to promote the utilization of mine water resources and ecological environment protection, and achieve the purpose of utilizing water resources and ensuring water security.

[0032] Water flows out from the No. 4 shaft of the mine and enters the water purification zone 1. After undergoing sedimentation and preliminary ecological purification treatment in the water purification zone 1, it enters the water storage zone 2.

[0033] In water storage zone 2, the "sponge" soil is reconstructed to retain and store mine water.

[0034] The downstream water use zone 3 will "release" and utilize the water stored in the water storage zone 2 when needed or in excess, thereby promoting the utilization of mine water resources and ecological environmental protection.

[0035] Specific construction method:

[0036] (a) Before laying the waterproof layer, the topsoil of the surface subsidence basin in the mining area (for future coating) is stripped off, and the ground fissures caused by mining are treated by grouting.

[0037] (b) Constructing an isolation layer: The thickness of the water-resistant layer is 0.2-0.5m, and it is made of soil and fly ash through compaction. The permeability coefficient of the water-resistant layer is <0.1m / d, and the compaction degree is 1200-1400KPa.

[0038] (c) Constructing a water purification functional zone: Constructing an artificial wetland in the water purification functional zone, consisting of a water storage layer and a soil layer from top to bottom; the soil layer consists of soil stripped from the impermeable layer, broken rock mass, and fly ash, and aquatic plants are planted on the soil layer. The mass ratio of the soil stripped from the impermeable layer, broken rock mass, and fly ash is 4-5:1:3-4.

[0039] (d) Constructing a water storage functional zone: Reconstructing the "sponge" structure profile soil from top to bottom: including water retention layer 6 and planting nutrient layer 7.

[0040] The water-holding layer is composed of a mixture of plant fiber and sand and gravel, with plant fiber accounting for 15-25% of the volume of the mixture and sand and gravel accounting for 75-85% of the volume of the mixture; the water holding capacity of the water-holding layer is >100%, and the permeability coefficient is >10m / d; wherein the plant fiber is crop straw, cotton or hemp, with a particle size of less than or equal to 10mm; and the sand and gravel is one or more of coal gangue, river sand, and open-pit mine spoil, with a particle size of greater than or equal to 0.1mm.

[0041] The thickness of the planting nutrient layer 7 is 0.3-0.5m. The planting nutrient layer 7 is made by mixing soil with organic compost, humic acid and microbial agents. The mixed soil contains at least 1.5% organic matter. The soil is a water-resistant layer stripped soil. The organic compost is obtained by composting and fermenting agricultural and forestry waste. The agricultural and forestry waste is one or more of livestock and poultry manure, edible fungus residue, chestnut shells and fallen branches and leaves.

[0042] (e) Construct water use functional zones: Construct hydraulic facilities, water purification plants, and surface drainage ditch gates near water use functional zone 3. Release and utilize the stored water when needed or in excess.

[0043] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for constructing a "sponge" mining area using underground mining subsidence zones, characterized in that, On the horizontal plane distribution of the surface subsidence basin in the mining area, it is divided into three water resource functional zones in sequence: water purification functional zone (1), water storage functional zone (2), and water use functional zone (3). The water purification functional area (1) is located in the upstream area of ​​the water flow at the edge of the surface subsidence basin in the mining area; the water storage functional area (2) is located in the central area of ​​the surface subsidence basin in the mining area; and the water use functional area (3) is located in the downstream area of ​​the water flow in the surface subsidence basin in the mining area. Water flows out from the wellhead of mine (4) and enters the water purification zone (1). After sedimentation and preliminary ecological purification treatment in the water purification zone (1), it enters the water storage zone (2). In the water storage functional area (2), the mine water is conserved and stored by reconstructing the "sponge" soil. The downstream water use zone (3) will "release" and utilize the water stored in the water storage zone (2) when needed or in excess, thereby promoting the utilization of mine water resources and ecological environmental protection. A waterproof layer (5) is laid on the collapsed surface of the water purification functional area (1), water storage functional area (2) and water use functional area (3); the thickness of the waterproof layer is 0.2-0.5m, and it is made of soil and fly ash by compaction. The permeability coefficient of the waterproof layer is <0.1m / d, and the compaction degree is 1200-1400KPa; before laying the waterproof layer, the surface soil of the collapsed basin of the mining area is stripped, and the ground fissures caused by mining are treated by grouting. The water purification functional area (1) is constructed as an artificial wetland, which includes a water storage layer and a soil layer from top to bottom; the soil layer is composed of soil stripped from the water-proof layer, broken rock mass and fly ash, and aquatic plants are planted on the soil layer; The water storage functional area (2) is reconstructed from top to bottom into a water-holding layer (6) and a planting nutrient layer (7); the water-holding layer is made of a mixture of plant fiber and sand and gravel, with plant fiber accounting for 15-25% of the volume of the mixture and sand and gravel accounting for 75-85% of the volume of the mixture; the water holding capacity of the water-holding layer is >100%, and the permeability coefficient is >10m / d; the plant fiber is crop straw, cotton or hemp, with a particle size of less than or equal to 10mm; the sand and gravel is one or more of coal gangue, river sand, and open-pit mine spoil, with a particle size of greater than or equal to 0.1mm.

2. The method for constructing a "sponge" mining area using underground mining subsidence zones according to claim 1, characterized in that, The mass ratio of the soil stripped from the aquitard, the fractured rock mass, and the fly ash is 4-5:1:2-3.

3. The method for constructing a "sponge" mining area using underground mining subsidence zones according to claim 1, characterized in that, The thickness of the planting nutrient layer (7) is 0.3-0.5m. The planting nutrient layer (7) is made by mixing soil with organic compost, humic acid and microbial agents. The mixed soil contains at least 1.5% organic matter. The soil is a water-resistant layer stripped soil. The organic compost is obtained by composting and fermenting agricultural and forestry waste. The agricultural and forestry waste is one or more of livestock and poultry manure, edible fungus residue, chestnut shells and fallen leaves.

4. The method for constructing a "sponge" mining area using underground mining subsidence zones according to claim 1, characterized in that, Near the water use functional area (3), construct hydraulic facilities, water purification plant, and surface drainage ditch gate.

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