Method and system for zoning water-saving coal mining in mining areas based on post-mining groundwater level recovery time

Abstract

The present invention provides a method and system for zoning water-saving coal mining in a mining area based on the recovery time of groundwater level after mining, which relates to the field of coal mining and green mining technology, including: obtaining basic geological information, groundwater level information of monitoring wells and vegetation coverage information in the mining area; obtaining a distribution map of the mean burial depth of historical groundwater level before coal seam mining; obtaining a distribution map of vegetation coverage rates at different levels and a zoning map of vegetation sensitivity to groundwater depth; obtaining distribution maps of safe water levels at different levels according to the threshold of groundwater ecological safety water level under different conditions, calculating the time required for the water level in each grid unit to recover to the threshold of ecological safety water level depth based on the ecological water level recovery time prediction method, and forming a zoning map of ecological water level recovery time after mining; determining the ecological restoration zoning standard of water-saving coal mining mines, superimposing the restoration time zoning map and the vegetation sensitivity zoning map, dividing the mine into water-saving coal mining ecological restoration modes, and obtaining a zoning map of grade and type of water-saving coal mining mines.

Description

Technical Field

[0001] The present disclosure relates to the field of coal mining and green mining technology, and in particular to a method and system for zoning water-saving coal mining areas in a mining area based on the recovery time of a groundwater level after mining. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] At present, some arid and semi-arid areas belong to ecologically fragile areas, with insufficient precipitation, water resources shortage, serious land desertification and desertification problems, resulting in barren land, sparse vegetation, and the ecosystem is easily out of balance. With the intensification of mining activities in western mining areas, the protection of water resources and the maintenance of the ecological environment in mining areas face great challenges. Reducing water resource losses during mineral resource development is the focus of water resource management in ecologically fragile mining areas.

[0004] At present, water-saving coal mining zoning is mainly carried out from the perspectives of coal-aquiclude-water spatial relationship and other coal mining geological conditions, ecological water level decline, vegetation and groundwater constraints, coal seam overburden water-proof characteristics, environmental engineering geological models, shallow surface water resources distribution law and mathematical theory evaluation methods. The research results are of great significance to water-saving coal mining in Northwest mining areas. At present, there is no relevant report on the study of water-saving coal mining zoning from the perspective of groundwater level recovery time.

[0005] However, with the large-scale mining of coal resources in the mining area, the mining depth has gradually increased. The impact of coal mining on groundwater resources has been reduced when mining shallow buried coal seams, but there is still mining leakage in the mining area, and then the groundwater recovers to varying degrees. The length of time for groundwater level recovery has a significant impact on the vegetation ecology in the mining area. Based on this, the relevant research on the water conservation coal mining zoning method in the western mining area is carried out from the perspectives of ecological water level recovery time and vegetation ecological sensitivity, which is of great significance to the ecological environment protection and coal production capacity planning of the mining area. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a method and system for zoning water-preserving coal mining in mining areas based on the recovery time of the groundwater level after mining, which can solve the problem of zoning water-preserving coal mining areas under coal seam mining, and provide a theoretical reference basis for safe mining of mines, protection of the ecological and geological environment of mining areas, and planning of coal production capacity in mining areas.

[0007] According to some embodiments, the present disclosure adopts the following technical solutions:

[0008] The method of zoning water-saving coal mining in mining areas based on the recovery time of the groundwater level after mining includes:

[0009] Obtain basic geological information within the mining area, groundwater level information in monitoring wells, and vegetation coverage information;

[0010] According to the phreatic water level information of the monitoring well, the mean distribution map of the historical phreatic water level before coal seam mining is obtained;

[0011] Based on the vegetation coverage information, the mean value of the historical average vegetation coverage FVC before coal seam mining was calculated to obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth;

[0012] According to the threshold value of groundwater ecological safety water level under different conditions, the distribution maps of safe water levels of different levels are obtained, and the time required for the water level in each grid unit to recover to the ecological safety water level burial depth threshold is calculated based on the ecological water level recovery time prediction method to form a post-mining ecological water level recovery time zoning map; the ecological restoration zoning standards for water-preserving coal mining mines are determined, the recovery time zoning map and the vegetation sensitivity zoning map are superimposed, the mines are divided into water-preserving coal mining ecological restoration modes, and a grade type zoning map for water-preserving coal mining mines is obtained.

[0013] According to some embodiments, the present disclosure adopts the following technical solutions:

[0014] The water conservation coal mining zoning system in the mining area based on the recovery time of the groundwater level after mining includes:

[0015] Data acquisition module, used to obtain basic geological information in the mining area, groundwater level information of monitoring wells and vegetation coverage information;

[0016] The data analysis module is used to obtain the mean value distribution map of the historical groundwater level before coal mining based on the groundwater level information of the monitoring well;

[0017] Based on the vegetation coverage information, the mean value of the historical average vegetation coverage FVC before coal seam mining was calculated to obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth;

[0018] The zoning module is used to obtain different levels of safe water level distribution maps according to the groundwater ecological safety water level threshold under different conditions, calculate the time required for the water level in each grid unit to recover to the ecological safety water level burial depth threshold based on the ecological water level recovery time prediction method, and form a post-mining ecological water level recovery time zoning map; determine the ecological restoration zoning standards for water-preserving coal mining mines, superimpose the recovery time zoning map and the vegetation sensitivity zoning map, divide the mines into water-preserving coal mining ecological restoration modes, and obtain a grade type zoning map for water-preserving coal mining mines.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present disclosure provides a method for zoning water-saving coal mining in a mining area based on the recovery time of the groundwater level after mining. The depth of shallow groundwater in the study area is zoned using ArcGIS according to the groundwater level data in the mining area; the determination of the threshold of the depth of ecologically safe groundwater level is mainly based on the ecological geological environment type determined by the surface topography and vegetation factors in the study area and the hydrogeological type determined by the aquifer medium, groundwater recharge and runoff conditions. In addition, the response of ecological and environmental factors such as vegetation growth, river and lake base flow and land desertification to water level changes will also affect its threshold. Therefore, the threshold of the depth of ecologically safe water level can be obtained by combining the climatic conditions, hydrogeological conditions, etc. in each region to obtain the influence of multiple factors on water level changes. Through the method of predicting the recovery of groundwater level, the time for groundwater at different depths to recover to the depth of ecologically safe water level is zoned; on the basis of the law of evolution of recovery time, factors such as vegetation ecology are considered at the same time, and the water-saving coal mining grade is zoned according to the length of water level recovery time. It mainly focuses on the coordinated relationship between coal mining and groundwater, and judges the ecological status of the mining area after mining by predicting the groundwater recovery time, so as to propose more effective water conservation coal mining measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0022] Figure 1 The present invention is a method flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] Example 1

[0027] In one embodiment of the present disclosure, a method for zoning water-saving coal mining areas in a mining area based on post-mining groundwater level recovery time is provided, comprising the following steps:

[0028] Step 1: Obtain basic geological information, groundwater level information of monitoring wells and vegetation coverage information in the mining area;

[0029] Step 2: Obtain the mean distribution map of the historical phreatic water level before coal seam mining based on the phreatic water level information of the monitoring well;

[0030] Step 3: Based on the vegetation coverage information, calculate the mean value of the historical average vegetation coverage FVC before coal seam mining, obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth;

[0031] Step 4: According to the threshold value of groundwater ecological safety water level under different conditions, obtain the distribution maps of safe water levels of different levels, calculate the time required for the water level in each grid unit to recover to the threshold value of ecological safety water level burial depth based on the ecological water level recovery time prediction method, and form a post-mining ecological water level recovery time zoning map; determine the ecological restoration zoning standards for water-preserving coal mining mines, superimpose the recovery time zoning map and the vegetation sensitivity zoning map, divide the mines into water-preserving coal mining ecological restoration modes, and obtain a grade type zoning map for water-preserving coal mining mines.

[0032] As an embodiment, the specific implementation process of the method for zoning water-saving coal mining in a mining area based on the post-mining water level recovery time disclosed in the present invention includes:

[0033] Step 1: Collect relevant data such as geological conditions in the mining area, coal seam mining conditions, groundwater level monitoring well information, and vegetation information obtained by remote sensing monitoring;

[0034] Step 2: Based on the groundwater level observation data from multiple monitoring wells in the mining area, draw a distribution map of the average groundwater level depth for many years before coal seam mining;

[0035] Step 3: Based on the vegetation information obtained from remote sensing monitoring, the average vegetation coverage FVC of the coal seam before mining was calculated by ArcGIS raster, and the distribution map of vegetation coverage at different levels was drawn. The sensitivity of vegetation to groundwater depth was divided into different zones in the study area.

[0036] Step 4: Combined with the topography, hydrogeological conditions, and vegetation growth in the study area, analyze the groundwater ecological safety water level thresholds in the study area under different conditions, and use ArcGIS data spatial processing functions to draw thematic maps of groundwater ecological safety water level threshold zoning under different conditions in the study area;

[0037] Step 5: Based on the ecological water level recovery time prediction method, calculate the time required for the water level in each grid unit of the study area to recover to the ecological safety water level burial depth threshold, and analyze the evolution law of ecological safety water level recovery time in different regions to form a post-mining ecological water level recovery time zoning map;

[0038] Step 6: Based on the law of evolution of restoration time, taking into account factors such as vegetation ecology, determine the ecological restoration zoning standards for water-conserving coal mining mines. Superimpose the recovery time zoning map drawn in step 5 and the vegetation sensitivity zoning map drawn in step 3, divide the mines into water-conserving coal mining ecological restoration modes, and form a grade type zoning map of water-conserving coal mining mines in the study area.

[0039] Furthermore, the geological conditions and coal seam mining conditions used to estimate the post-mining water level recovery time described in step 1 include: the structure of the overlying rock strata, soil strata, phreatic aquifers and other rock strata in the mining area, the thickness of each rock stratum, density, elastic modulus, internal friction angle, cohesion and Poisson's ratio and other main physical and mechanical parameters; the permeability coefficient, porosity and water supply degree of the overlying impermeable rock strata or soil strata and other hydrogeological parameters; the burial depth of the coal seam, the mining thickness of the coal seam, the oblique length of the working face, the coal mining method, the relative position of the water level monitoring well and the coal mining working face, etc.;

[0040] The data of the submersible monitoring wells include: ground elevation of the mining area, location of the water level monitoring wells and the data of the submersible level;

[0041] Remote sensing monitoring information may include: NDVI values ​​calculated based on MODIS image data from TERRA satellite images and related meteorological data.

[0042] In step 2, specifically: based on geostatistical theory, combined with the existing water level and elevation data related to the groundwater level monitoring wells, the ordinary Kriging interpolation method in ArcGIS software is used to obtain the groundwater depth contour map of the continuous time period determined before mining, such as the entire dry year mining area, and the annual average groundwater depth contour map of the study area before mining is obtained through the raster calculator in ArcGIS.

[0043] Furthermore, in step 3, the vegetation coverage FVC and water level depth distribution in the study area, as well as the sensitivity relationship between FVC and water level depth changes, are combined to draw a vegetation sensitivity zoning map in the study area, specifically:

[0044] Step 3.1 Draw a vegetation coverage zoning map in the study area

[0045] The vegetation coverage fraction (FVC) refers to the ratio of the vertical projection area of ​​the vegetation canopy to the statistical effective area, and is an important indicator for characterizing the growth characteristics and distribution of surface vegetation. The normalized difference vegetation index (NDVI) is used to estimate FVC, as shown in equations (1) and (2).

[0046]

[0047] Where: FVC is the vegetation coverage; NDVI is the normalized difference vegetation index; NDVI soilIt is the NDVI value of the pixel with almost bare soil or no vegetation cover; NDVI veg is the NDVI value of the pixel with approximate full vegetation coverage.

[0048]

[0049] Where: nir is the near infrared band in MODIS images; ρ red It is the near-red band in MODIS images;

[0050] Combined with the actual situation in the study area, the vegetation coverage is divided into three levels: low coverage, medium coverage, and high coverage. The specific classification standards are shown in Table 1.

[0051] Table 1 Fractional vegetation coverage (FVC) levels

[0052]

[0053] The mean FVC of the average vegetation coverage over many years in the same period as that taken in step 2 was obtained through ArcGIS raster calculation, and the zoning map of vegetation coverage at different levels was drawn.

[0054] Step 3.2 Combine the sensitivity relationship between FVC and water level depth to draw a vegetation sensitivity zoning map in the study area

[0055] According to the statistical relationship analysis of FVC and groundwater depth in existing studies, when the groundwater depth in the windy beach area of ​​northern Shaanxi is 1.5-8.0m, as the groundwater depth increases, the suitable vegetation types gradually decrease, and the FVC value decreases accordingly, which has a negative impact on the entire vegetation ecology, among which the impact on the low coverage area is the greatest; when the groundwater depth is 8-10m, due to the influence of meteorological, topographical, and human activities factors, FVC shows a reverse trend of gradually increasing, which has a relatively positive impact on the entire vegetation ecology; when the groundwater depth is less than 1.5m and greater than 10m, FVC is not sensitive. Based on this, the vegetation sensitivity before mining is divided into different zones, and the specific division criteria are shown in Table 2.

[0056] Table 2 Classification criteria for vegetation sensitivity types

[0057]

[0058] Through ArcGIS, the groundwater depth distribution map was kept consistent with the spatial resolution of the vegetation remote sensing image, the FVC was raster-aligned with the groundwater depth data under the same scale conditions, the groundwater depth contour map of the same period was superimposed with the vegetation coverage zoning map, the groundwater depth distribution map was kept consistent with the spatial resolution of the vegetation remote sensing image, the FVC was raster-aligned with the groundwater depth data under the same scale conditions, and the vegetation sensitivity zoning map of the study area was determined by extracting FVC and groundwater depth data on the same grid and combining the standard range in Table 2 to form the vegetation sensitivity zoning map of the study area.

[0059] Furthermore, in step 4, the ecological safety groundwater level depth threshold zoning map of the study area is drawn as follows:

[0060] Step 4.1 Determine the factors affecting the ecological safety groundwater level depth threshold

[0061] The determination of the threshold of the depth of the ecologically safe groundwater level is mainly based on the ecological geological environment type determined by the surface topography and vegetation factors in the study area, and the hydrogeological type determined by the aquifer medium, groundwater recharge and runoff conditions. In addition, the response of ecological and environmental factors such as vegetation growth, river and lake base flow and land desertification to water level changes will also affect its threshold.

[0062] Step 4.2 Specific steps for determining the ecological safety groundwater level depth threshold

[0063] First, through the investigation and analysis of regional topography, vegetation, surface water and other ecological-water-geological information, it is divided into different ecological-geological environmental units, such as arid and semi-arid areas, windy beach areas, plain areas, etc. According to the collected interannual groundwater level dynamic data of different hydrogeological units in the study area, the historical regression method of groundwater level and groundwater ecological environment is used to construct the corresponding quantitative relationship model based on the water level data of each representative monitoring well, and determine the ecological water level threshold of different hydrogeological units.

[0064] Step 4.3: Combine existing empirical values ​​and model calculations to zoning different ecological safety groundwater depth thresholds in the study area

[0065] The current research results show that the corresponding empirical values ​​of the ecological safety groundwater level depth threshold under different representative ecological geological environments are shown in Table 3. Based on the existing empirical values, combined with model calculations, and using ArcGIS data statistical tools, the distribution map of the ecological safety groundwater level depth threshold in the study area was drawn.

[0066] Table 3 Empirical values ​​of ecological safety groundwater level depth thresholds

[0067]

[0068] Furthermore, in step 5, the existing method for estimating the recovery time of the groundwater ecological water level is used to calculate the time required for the water level in each area to recover to the ecological safety water level depth threshold determined in step 4, and the recovery time of each grid unit is proposed based on the ArcGIS spatial analysis function. The groundwater level recovery time at different depths in the study area is divided into rapid recovery (less than half a year), relatively fast recovery (half a year to one year), recoverable (one to three years), and difficult to recover (more than three years), and a recovery time differentiation map is drawn.

[0069] Furthermore, step 6 needs to combine the groundwater recovery law zoning obtained in step 5 with the sensitivity of vegetation to groundwater obtained in step 3, and divide the water-saving coal mining grade of the mining area according to the response relationship between vegetation coverage and groundwater depth, and other factors such as climate, soil texture, topography and human activities. The specific steps are:

[0070] Step 6.1 Determine the zoning standards for water-saving coal mining

[0071] The specific zoning standards are shown in Table 4. The first-level water-conserving coal mining mine refers to the area where the groundwater level recovers quickly after mining, and the water level changes caused by mining in the mining area will have a negative impact on the vegetation coverage, and the mine is not suitable for vegetation growth due to the large buried water level. This type of mine must take compulsory measures to mine; the second-level water-conserving coal mining mine refers to the area where the groundwater level can be restored after mining, and the water level changes caused by mining in the mining area will have a negative impact on the vegetation coverage, and the mine is not suitable for vegetation growth due to the large buried water level. This type of mine needs to take certain measures before mining; the third-level water-conserving coal mining mine refers to the area where the groundwater level is difficult to recover after mining, and the water level changes caused by mining in the mining area will have a negative impact on the vegetation coverage, and the mine is not suitable for vegetation growth due to the large buried water level. This type of mine can be artificially restored for the ecological environment after mining.

[0072] Table 4 Classification standards for water-saving coal mining mines

[0073]

[0074]

[0075] Step 6.2 Draw a distribution map of water-saving coal mining mine grades according to the standards in Table 4

[0076] According to the standards in Table 4, after registration using ArcGIS, the restoration degree zoning map drawn in step 5 and the vegetation sensitivity zoning map drawn in step 3 are superimposed. The restoration degree zoning map is first registered with the vegetation sensitivity zoning map, and the sensitivity and water level restoration degree in the same grid are superimposed. The water-retaining coal mining type zoning mine map is redrawn according to the standards in Table 4. The distribution map of the grade and type of water-retaining coal mining mines in the study area is obtained.

[0077] Example 2

[0078] In one embodiment of the present disclosure, a system for zoning water-saving coal mining areas in a mining area based on post-mining groundwater level recovery time is provided, comprising:

[0079] Data acquisition module, used to obtain basic geological information in the mining area, groundwater level information of monitoring wells and vegetation coverage information;

[0080] The data analysis module is used to obtain the mean value distribution map of the historical groundwater level before coal mining based on the groundwater level information of the monitoring well;

[0081] Based on the vegetation coverage information, the mean value of the historical average vegetation coverage FVC before coal seam mining was calculated to obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth;

[0082] The zoning module is used to obtain different levels of safe water level distribution maps according to the groundwater ecological safety water level threshold under different conditions, calculate the time required for the water level in each grid unit to recover to the ecological safety water level burial depth threshold based on the ecological water level recovery time prediction method, and form a post-mining ecological water level recovery time zoning map; determine the ecological restoration zoning standards for water-preserving coal mining mines, superimpose the recovery time zoning map and the vegetation sensitivity zoning map, divide the mines into water-preserving coal mining ecological restoration modes, and obtain a grade type zoning map for water-preserving coal mining mines.

[0083] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0085] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A method for zoning coal mining areas for water conservation based on the recovery time of the groundwater level after mining, characterized in that: include: Obtain basic geological information, groundwater level monitoring well information and vegetation coverage information within the mining area; According to the phreatic water level information of the monitoring well, the mean distribution map of the historical phreatic water level before coal seam mining is obtained; Based on the vegetation coverage information, the mean value of the historical average vegetation coverage FVC before coal seam mining was calculated to obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth; The process of obtaining the zoning map of vegetation sensitivity to groundwater depth is as follows: first obtain the distribution map of vegetation coverage at different levels. The vegetation coverage FVC is the ratio of the area of ​​the vertical projection of the vegetation canopy to the area of ​​the statistical effective area. The normalized vegetation index NDVI is used to estimate FVC. According to the division standard, the vegetation coverage is divided into three levels: low coverage, medium coverage and high coverage. The average vegetation coverage FVC mean value of the set continuous period is obtained through ArcGIS raster calculation, and the zoning map of vegetation coverage at different levels is drawn. Combined with the sensitivity relationship between FVC and water level depth changes, the vegetation sensitivity zoning map in the study area was obtained, including: obtaining the statistical relationship between historical FVC and groundwater depth, formulating the division standard, using ArcGIS to keep the mean distribution map of groundwater level depth consistent with the spatial resolution of vegetation remote sensing images, rasterizing FVC with groundwater depth data under the same scale conditions, and superimposing the groundwater depth contour map of the same period with the vegetation coverage zoning map to form the vegetation sensitivity zoning map of the study area; According to the threshold of groundwater ecological safety water level under different conditions, obtain the distribution map of safe water level of different levels, calculate the time required for the water level in each grid unit to recover to the threshold of ecological safety water level burial depth based on the ecological water level recovery time estimation method, and form the ecological water level recovery time zoning map after mining; determine the ecological restoration zoning standard of water-preserving coal mining wells, superimpose the restoration time zoning map and the vegetation sensitivity zoning map, divide the mines into water-preserving coal mining ecological restoration modes, and obtain the grade type zoning map of water-preserving coal mining wells; According to the threshold of groundwater ecological safety water level under different conditions, the distribution map of safe water level of different levels is obtained, including: determining the influencing factors of the threshold of ecological safety groundwater level depth, obtaining the ecological-water-geological information of regional topography, vegetation and surface water bodies, dividing them into different ecological geological environment units, using the historical regression method of groundwater level and groundwater ecological environment, constructing the corresponding quantitative relationship model based on the water level data of each representative monitoring well, determining the threshold of ecological water level of different hydrogeological units, and combining the empirical value and model to divide the threshold of different ecological safety groundwater level depth in the study area; The method for estimating the recovery time of groundwater ecological water level is to calculate the time required for the water level in each area to recover to the ecological safety water level depth threshold determined in the first step, and propose the recovery time of each grid unit based on ArcGIS spatial analysis. The groundwater level recovery time of different depths in the study area is divided into rapid recovery, fast recovery, recoverable and difficult to recover, and a recovery time differentiation map is drawn; Zoning the water-preserving coal mining grade in the mining area includes: determining the zoning standards for water-preserving coal mining mines, and according to the standards, superimposing the restoration degree zoning map and the vegetation sensitivity zoning map after ArcGIS registration to obtain the distribution map of the grade and type of water-preserving coal mining mines in the study area.

2. The method for zoning water-saving coal mining in a mining area based on the post-mining water level recovery time according to claim 1, characterized in that: The basic geological information in the mining area refers to the geological conditions and coal seam mining conditions, specifically including the rock structure of the overlying rock strata, soil strata and phreatic aquifer in the mining area, the physical and mechanical parameters of the thickness, density, elastic modulus, internal friction angle, cohesion and Poisson's ratio of each rock stratum, the permeability coefficient, porosity and water supply hydrogeological parameters of the overlying impermeable rock strata or soil strata; the burial depth of the coal seam, the mining thickness of the coal seam, the inclined length of the working face, the coal mining method, and the relative position of the water level monitoring well and the coal mining working face.

3. The method for zoning water-saving coal mining in a mining area based on the post-mining water level recovery time according to claim 1, characterized in that: The information of groundwater level monitoring wells and vegetation coverage includes: ground elevation of the mining area, location of water level monitoring wells and groundwater level data; vegetation coverage information is obtained by remote sensing monitoring, including: MODIS image data based on TERRA satellite images, NDVI values ​​and meteorological data.

4. The method for zoning water-saving coal mining in a mining area based on the post-mining water level recovery time according to claim 1, characterized in that: The process of obtaining the mean distribution map of the groundwater level depth is as follows: based on statistical theory, combined with the historical water level and elevation information of the groundwater level monitoring wells, the Kriging interpolation method of ArcGIS software is used to obtain the groundwater depth contour maps of the mining area for consecutive time periods set before mining, and the average annual groundwater depth contour map of the study area before mining is obtained through the raster calculator in ArcGIS.

5. A water-saving coal mining zoning system based on the post-mining groundwater level recovery time is characterized by: include: Data acquisition module, used to obtain basic geological information, groundwater level monitoring well information and vegetation coverage information in the mining area; The data analysis module is used to obtain the mean value distribution map of the historical groundwater level before coal mining based on the groundwater level information of the monitoring well; Based on the vegetation coverage information, the mean value of the historical average vegetation coverage FVC before coal seam mining was calculated to obtain the distribution map of vegetation coverage rates at different levels and the zoning map of vegetation sensitivity to groundwater depth; The process of obtaining the zoning map of vegetation sensitivity to groundwater depth is as follows: first obtain the distribution map of vegetation coverage at different levels. The vegetation coverage FVC is the ratio of the area of ​​the vertical projection of the vegetation canopy to the area of ​​the statistical effective area. The normalized vegetation index NDVI is used to estimate FVC. According to the division standard, the vegetation coverage is divided into three levels: low coverage, medium coverage and high coverage. The average vegetation coverage FVC mean value of the set continuous period is obtained through ArcGIS raster calculation, and the zoning map of vegetation coverage at different levels is drawn. Combined with the sensitivity relationship between FVC and water level depth changes, the vegetation sensitivity zoning map in the study area was obtained, including: obtaining the statistical relationship between historical FVC and groundwater depth, formulating the division standard, using ArcGIS to keep the mean distribution map of groundwater level depth consistent with the spatial resolution of vegetation remote sensing images, rasterizing FVC with groundwater depth data under the same scale conditions, and superimposing the groundwater depth contour map of the same period with the vegetation coverage zoning map to form the vegetation sensitivity zoning map of the study area; The zoning module is used to obtain different levels of safe water level distribution maps according to the groundwater ecological safety water level threshold under different conditions, calculate the time required for the water level in each grid unit to recover to the ecological safety water level burial depth threshold based on the ecological water level recovery time prediction method, and form a post-mining ecological water level recovery time zoning map; determine the ecological restoration zoning standards for water-preserving coal mining mines, superimpose the restoration time zoning map and the vegetation sensitivity zoning map, divide the mines into water-preserving coal mining ecological restoration modes, and obtain a water-preserving coal mining mine grade type zoning map; According to the threshold of groundwater ecological safety water level under different conditions, the distribution map of safe water level of different levels is obtained, including: determining the influencing factors of the threshold of ecological safety groundwater level depth, obtaining the ecological-water-geological information of regional topography, vegetation and surface water bodies, dividing them into different ecological geological environment units, using the historical regression method of groundwater level and groundwater ecological environment, constructing the corresponding quantitative relationship model based on the water level data of each representative monitoring well, determining the threshold of ecological water level of different hydrogeological units, and combining the empirical value and model to divide the threshold of different ecological safety groundwater level depth in the study area; The method for estimating the recovery time of groundwater ecological water level is to calculate the time required for the water level in each area to recover to the ecological safety water level depth threshold determined in the first step, and propose the recovery time of each grid unit based on ArcGIS spatial analysis. The groundwater level recovery time of different depths in the study area is divided into rapid recovery, fast recovery, recoverable and difficult to recover, and a recovery time differentiation map is drawn; Zoning the water-preserving coal mining grade in the mining area includes: determining the zoning standards for water-preserving coal mining mines, and according to the standards, superimposing the restoration degree zoning map and the vegetation sensitivity zoning map after ArcGIS registration to obtain the distribution map of the grade and type of water-preserving coal mining mines in the study area.

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