Study on the Restoration of Ecological Environments in Mining Area Based on GIS Technology

Abstract

Taking Erdaojiang and Dongchang District of Tonghua City, Jilin Province as examples, this paper studies the ecological environment restoration and governance model of their mining areas. In this paper, the vegetation cover (NDVI) data in the past ten years were selected from the study area. The Theil–Sen median and Mann–Kendall (MK) methods were used to analyze the time series of NDVI, and the vegetation cover change trend map of the study area was obtained. Then, the land use data of the study area for 4 years were selected, and the transfer matrix method was used to analyze the land use conversion between the years. Finally, according to the characteristics of the distribution of mines in the study area, for the mining area in different natural geographical locations, it was concluded that the restoration of cultivated land and the restoration of forest land and ecological reconstruction were adopted. Among them, the restoration of forest land includes natural restoration and artificial intervention.

1. Introduction

China’s mining industry has become more mature after decades of development. The rapid growth of the mining industry is a major industry promoting the economy. The history of mineral development in Tonghua City can be traced back to the 1960s. The development of mineral resources promoted urban construction and the economic and social development of Tonghua City. With the development of the new era concept of “ lucid waters and lush mountains are invaluable assets”, the problem of a mine’s ecological geological environment has received increasing attention. The impact of production mines and closed and abandoned mines on the environment and restoration and management have become the focus of research. With the rapid development of the mining industry, many environmental problems have followed. The protection and restoration of the ecological environment are key tasks in the construction of ecological civilization in China [1].

The most direct sense brought by mining is the large-scale destruction of vegetation, that is, the destruction of landscape, and the destruction and loss of cultivated land, woodland, and pastures, which have the most direct impact on human production and life. It will also cause indirect effects, including soil erosion, air pollution, water pollution, lack of animal and plant diversity, and other indirect effects [2,3] Mining activities have the most serious impact on the mining ecosystem. Even after mining stops, most of these effects will persist over large areas of land. Facing the increasing requirements of environmental protection and ecologically sustainable development, mine land reclamation and ecological restoration have become a research hotspot [4]. In order to reduce environmental pollution and protect the ecological environment, the environmental management of mining areas in China began in the 1950s and 1960s. A simple combination of traditional vegetation reconstruction and several engineering techniques may not guarantee complete long-term recovery. Therefore, the goal of mine restoration should not be limited to eliminating environmental pollution and plant restoration but should include ecosystem reconstruction and local landscape design. Integrated approaches and techniques based on multiple considerations, including restoration ecology and landscape ecology, have proven to be more effective in the long term [5].

The process of mineral development is bound to cause severe disturbance to the above-ground and underground space of the mining area, which in turn leads to secondary damage to the surrounding environment [6]. The impact on the ecological environment of the mining area is multifaceted, and it is not only closely related to human activities but also directly related to climate change [7,8,9]. The process of ecological environment restoration is slow, and it is necessary to find appropriate restoration methods, accelerate the restoration process, and give priority to the treatment of ecologically fragile areas [10,11,12]. Human activities have a significant impact on the ecosystem of mine sites, and these activities have intensified over time [13,14]. The ecological restoration of a mining area adopts remote sensing monitoring technology, which can clearly determine the ecological environment status in recent years [15,16]. The mine restoration and management model is based on the ecological geological environment [17], guided by land space planning, and integrates the “social-economic-natural” factors [18]. Based on the characteristics of rich coal resources and the fragile ecological environment in the Yellow River Basin, Bian Zhengfu [19] constructed a model to evaluate the geological ecological carrying capacity of the Yellow River Basin and proposed to pay equal attention to ecological protection and restoration and develop a high-quality coal economy. Yu Haochen et al. [20] analyzed the characteristics of land ecosystem degradation in mines and revealed that the three thresholds of land system degradation correspond to natural, mixed, and artificial measures for mine restoration. On the basis of following the development of regional natural ecosystems, Lei et al. [21] guided the restoration of damaged vegetation according to different site conditions so that the restoration method was more in line with the original ecosystem. Su Haifeng et al. [22] developed a new type of slow-release microbial fertilizer that can adsorb a variety of microorganisms. The use of fly ash as a carrier matrix provides a green engineering method to recover fly ash for mine greening. From the beginning, the concept of “first destruction, then reclamation” has gradually changed to the concept of “mining while reclamation” [23]. The restoration and management of ecological and geological mine environments comprise the practice of the concept of sustainable development. At the same time, there is a strong correlation between sustainable development and ecological geological environment restoration [24]. In the process of mining, the loss of ecosystem service functions is ignored, which affects sustainable development [25]. Zeng Xianlai and Li Jinhui [26] proposed the regulation and recycling of urban mineral resources (mainly metal resources). According to different rare earth mining methods used within 27 years, Li et al. [27] concluded that mining methods have great differences in the degree of damage to vegetation and land in the mining area. The optimization of mining technology has a positive effect on the ecological environment and is conducive to the sustainable development of the rare earth industry chain. Lin et al. [10] applied the principles and techniques of restoration ecology and landscape ecology to the process of mine restoration to improve the restoration effect and ensure the long-term effect of geological mine environment restoration. Zhao Fuqiang et al. [28] believe that the development of national mine parks after the completion of resource exploitation can improve the overall sustainability of mines. Using the sustainable development cube evaluation model, the social, economic, and environmental sustainability of 14 national mine parks in China before and after construction was evaluated. The evaluation shows that the mine parks have an increasing trend in both economic and environmental sustainability, while social sustainability was reduced due to the closure of mines and the increase in population outflow.

To summarize, for many scholars focused on eco-geological environment assessment, research on mine restoration and the management of related research is rich, but with respect to the mine restoration management model, targeted research studies number relatively few. First of all, these studies evaluate the ecological quality and environment and then evaluate the entire study area. Some areas are mainly large-scale mines, which do not achieve pertinence [29,30]. In this paper, the mine governance model of the study area is more specific to each mine in the study area and is aimed at small mines, increasing research in this area. Most previous studies aimed at large mines, because the degree of the mining of large mines is higher and the damage to the ecological environment is more serious; people tend to pay more attention to large mines in the same area, while small mines are often ignored. There are basically no special research studies on this kind of small mine, and some small mines are more suitable for natural recovery because the damage is not too serious. However, if the mine is not treated for a long time, it will also cause damage to the local ecological environment. In the research area of this paper, small mines are included, which is just enough to meet the study of the governance model of small mines.

The mining area comprises a typical fragile-type ecosystem with mineral resources [31]. The ecological and geological mine environment is a constantly changing system that changes with the time range and intensity of mining activities. The ecological quality of land in some mining areas has been on the verge of deterioration [32]. In this paper, taking Tonghua, a mining city in China, as the research area, the NDVI data of different time series in this region are extracted, and the NDVI change trend map is obtained by using Theil–Sen median and Mann–Kendall methods. The land use data from 2017 to 2020 are extracted, and the land use transfer matrix method is used to obtain the conversion between different land use types. The corresponding governance model is obtained according to the distribution location of mining sites combined with land use and the NDVI change trend, and reasonable suggestions are put forward for the study of a mine management model.

2. Materials and Methods

2.1. Study Area

The study area [33] is located in the southeast of Jilin Province, bordering Liuhe County in the north, Jian City in the south, Tonghua County in the west, and Baishan City in the east. It is 35 km long from north to south, 38 km wide from east to west, covering an area of 745 square kilometers, and it is located at 125°50′–126°20′ east longitude and 41°30′–41°55′ north latitude (Figure 1). The study area belongs to the northern temperate continental monsoon climate, with a frost-free period of 125–140 days and an annual sunshine period of 2411 h. The area with an average annual rainfall of 800–900 mm is distributed in the north of Tonghua City, and the average annual rainfall in most areas of Tonghua City is 700–800 mm. Most of them are concentrated in June–August, accounting for 61.3% of annual precipitation. The precipitation distribution in the study area is relatively uniform, and the difference is small. Precipitation has a large external force, which promotes the occurrence of geological disasters. Due to the serious damage to vegetation caused by mining in the study area coupled with the concentration of rainfall in the study area, geological disasters are easily caused. If the mine is not repaired, the damage to the ecological environment caused by geological disasters will continue to increase with the passage of time. The surface water in the study area belongs to the Hunjiang waters of the Yalu River system. There are 12 main and secondary rivers, of which the Hunjiang River is the main stream. Most rivers have a short flow path, rapid flow, large slope, and strong scouring force. The landform types in this area are mainly low mountains, intermountain canyons, and plains. The micro-topography along the river bank often comprises steep cliffs or steep slopes, and there are dense valleys between mountains and large slopes.

2.2. Technical Route

In this paper, vegetation cover data (NDVI) over a ten-year period and land use data over a six-year period were selected to study the area, and the NDVI data were analyzed using the Theil–Sen median method and the Mann–Kendall method to obtain a trend map. Land use data, using the transfer matrix method, obtained the trend of land use change. Combined with the distribution position of mining points, the corresponding mine management model map is obtained. The specific technology roadmap is shown in Figure 2.

2.3. Data Sources

In recent years, the application range of remote sensing has become more and more extensive, and thanks to the release of the Google Earth Engine platform, it is more convenient and faster to use remote sensing data to study vegetation changes. This paper selects 10 years of vegetation cover data (NDVI) from the Landsat 8 OIL platform with a resolution of 30 m, as shown in Figure 3. The land use data are from the FROM-GLC version 2 platform, with a resolution of 30 × 30 m, as shown in Figure 4. The mine map data were obtained from the Jilin Geological environment monitoring station (the Geological Environment Inspection Station of Jilin Province is an administrative department in China, from which mine data are obtained). The time series of the data used in this study is long, the data are free and easy to obtain, and the accuracy of the data is high. Based on the original data collection, ArcGIS 10.8 (ESRI, Redland, CA, USA) was used to uniformly transform and project the coordinate system, and the coordinate system adopted the unified WGS 1984 UTM Zone 52N projection coordinate system.

2.4. Methods

2.4.1. Theil–Sen Median Method and Mann–Kendall Test

In recent years, the application range of remote sensing has become more and more extensive, and thanks to the release of the Google Earth Engine platform, it is more convenient and faster to use remote sensing data to study vegetation changes. The analysis of the change characteristics of the annual vegetation index can be used as an indicator for the dynamic monitoring of the mining area of production mines and the reclamation of closed mines [34], so 10 years of NDVI change data were selected in this study [35]. At present, the commonly used trend analysis methods for NDVI changes include the univariate linear regression method [36] and the Theil–Sen median method [37]. Compared with univariate linear regression analysis, the advantage of the Theil–Sen median method is that it is less disturbed by data errors and outliers and is a robust trend calculation method for nonparametric statistics, which can well reduce the influence of noise. Because it is insensitive to measurement errors and outlier data, it is often used in the trend analysis of long-term series data [38]. This method is usually called the Sen slope estimation method, and its calculation formula is as follows:

$$\beta =\mathrm{Median}\left(\frac{NDV{I}_j-NDV{I}_i}{j-i}\right),2011\le i<j\le 2020$$

(1)

where $\beta$ is the trend of vegetation change, and $NDV{I}_j$ is the value of $NDVI$ in year $j$. $NDV{I}_i$ is the value of $NDVI$ in year $i$. If $\beta >0$, then $NDVI$ tends to increase. This indicates that vegetation has been improving or is recovering over a period of time. If $\beta <0$, then $NDVI$ is in a downward trend, indicating a tendency for vegetation degradation over the time period. Typically, Sen slope estimation is used to calculate trend values, which are then used in conjunction with the Mann–Kendall (MK) nonparametric test [39]. That is, the Sen trend value is calculated first, and then the MK method is used to determine the trend’s significance. For time series $NDV{I}_t=2011,2012\cdots 2020$, this is the (1) H₀ hypothesis, which assumes that the data in the sequence are independent distribution random samples; that is, there is no significant trend. The (2) H₁ hypothesis assumes that the sequence has a rising or falling monotonic trend. Under null hypothesis H₀, the formula of test statistic $S$ is as follows.

$$S={\sum }_{j=1}^{n-1} {\sum }_{i=j+1}^n \mathrm{s}\mathrm{g}\mathrm{n}\left(NDV{I}_j-NDV{I}_i\right)$$

(2)

In the formula, $\mathrm{s}\mathrm{g}\mathrm{n}\left(\right)$ is a sign function, and the calculation formula is as follows.

$$\mathrm{s}\mathrm{g}\mathrm{n}\left(NDV{I}_j-NDV{I}_i\right)=\left\{\begin{array}{cc}1,& NDV{I}_j-NDV{I}_i>0\\ 0,& NDV{I}_j-NDV{I}_i=0\\ -1,& NDV{I}_j-NDV{I}_i<0\end{array}\right.$$

(3)

The trend test is performed using test statistic $Z$ [40]. The $Z$ value is calculated as follows.

$$Z=\left\{\begin{array}{cc}\frac{S-1}{\sqrt{\mathrm{V}\mathrm{a}\mathrm{r}\left(S\right)}},& S>0\\ 0,& S=0\\ \frac{S+1}{\sqrt{\mathrm{V}\mathrm{a}\mathrm{r}\left(S\right)}},& S<0\end{array}\right.$$

(4)

The calculation formula of $\mathrm{V}\mathrm{a}\mathrm{r}\left(S\right)$ is as follows.

$$\mathrm{V}\mathrm{a}\mathrm{r}(S)=\left(n(n-1)(2n+5)-{\sum }_{i=1}^m t_i\left(t_i-1\right)\left(2t_i+5\right)\right)/18$$

(5)

In the formula, $n$ is the number of data in the sequence; $m$ is the number of data groups that appear repeatedly in the sequence; $t_i$ is the number of duplicate data in the group $i$ duplicate data group.

In a bilateral trend test, given significance level $\alpha$, if $\left|Z\right|⩽Z_{1-\alpha /2}$, then accept null hypothesis H0; that is, at confidence level $\alpha$, the sequence trend is not significant. If $Z>Z_{1-\alpha /2}$, it shows that there is a significant upward trend in the sequence data; if $Z<-Z_{1-\alpha /2}$, it shows that there is a significant downward trend in the sequence data [41]. In statistics, when the absolute value of $Z$ is greater than or equal to 1.645, 1.96, and 2.576, this means that it has passed the statistically significant test of 90%, 95%, and 99% confidence, respectively [42]. In this paper, the significance level of $\alpha =0.05$ is selected for testing; that is, when $\left|Z\right|>1.96$, it indicates that the $NDVI$ change trend is significant. The Theil–Sen median trend analysis and Mann–Kendall test results were superimposed to obtain a spatial distribution map of regional NDVI trends.

2.4.2. Land Use Transfer Matrix

The land use transfer matrix is used to obtain a two-dimensional matrix according to the changing relationship of land cover status in different phases of the same area. By analyzing the obtained transfer matrix, the mutual transformation between different land types in two phases can be obtained, and it describes land use types that change in different years and the location and area of change [43]. It can not only reflect the area data of each land type in the above static fixed area but also reflect the area that is transferred out of each land type in the initial stage and the area transferred in for each land type in the final stage. When we want to know whether the type of land use in this area has changed, we can observe whether the area of various land use types in the region has changed. The change in area is first reflected in the total change in different land use types. By analyzing the total change in land use types, we can understand the general trend of land use change and the change in land use structure.

3. Results and Discussion

3.1. NDVI Trends and Land Use Transformation

The process of exploitation and the utilization of mineral resources can be understood as the opposite-unified process of benefit and destruction. After the reform and opening up of China, mineral development entered a stage of expansionary development, and the ecological geological environment problems of mines changed from concentrated distributions in large and medium-sized mines to general distributions. Due to the lack of supervision means and weak environmental awareness, the ecological geological environmental problems of mines have gradually evolved from local to regional areas. A good ecological geological environment is a mutually beneficial and win–win situation, which is conducive to improving the quality of the living environment and mine production, but the fragile or deteriorating ecological geological environment will inevitably limit the sustainable development of mining. Mining will cause damage to the surrounding ecological environment, resulting in a decline in vegetation coverage, and NDVI will also decrease accordingly. Mine restoration can improve vegetation coverage through measures such as vegetation restoration and land improvement. By monitoring the change in NDVI value, we can understand the effect and progress of mine restoration, adjust the restoration measures in time, and improve the restoration effect. According to the changing trend of the NDVI time series, we can choose the recovery direction of the mining area and whether to use artificial restoration or natural restoration. According to the ten-year NDVI data, using the Theil–Sen median method and Mann–Kendall test and combined with

Table 1. Statistics of the NDVI Trend.

${\mathit{S}}_{\mathbf{N}\mathbf{D}\mathbf{V}\mathbf{I}}$	Z Value	Trend of NDVI	Percentage of Area
≥0.0005	≥1.96	Significant increase	16.49%
≥0.0005	−1.96–1.96	Slightly significant increase	45.35%
−0.0005–0.0005	−1.96–1.96	No change	9.32%
<−0.0005	−1.96–1.96	Slightly significant decrease	25.45%
<−0.0005	<−1.96	Significantly reduced	3.39%

The number of pixels with $S_{\mathrm{N}\mathrm{D}\mathrm{V}\mathrm{I}}$ between −0.0005 and 0.0005 Z > 1.96 or Z < −1.96 is very small, so this kind of pixel is classified as no change.

, the NDVI change trend chart is obtained, as shown in Figure 5. The trend is divided into five parts, namely significantly reduced, slightly significant decrease, no change, slightly significant increase, and significantly increase. No change accounted for 9.32%; a significant decrease of 3.39% was obtained; a slightly significant decrease of 25.45% was obtained; a significant increase of 16.49% was obtained; a slightly significant increase of 45.35% was obtained. According to the changing trend of NDVI, the areas with improved vegetation and degraded vegetation account for 61.84% and 28.84%, respectively, and the ecological environment is developing in a good direction. However, according to the distribution location of the mines, it can be concluded that most mines are within the area of vegetation degradation, and targeted mine restoration can better improve the local ecological environment. According to the trend analysis, the significantly reduced areas show that the vegetation is seriously damaged, while the areas with no obvious changes indicate that the protection of vegetation is better, and the ecology is more stable. The areas with improved vegetation are suitable for natural restoration, while areas with degraded vegetation are suitable for artificial restoration.

Land use types can directly reflect any changes in the ecological geological environment [31]. In the process of the rapid development of human society, with the change in the means of production, the type of human use of land is also changing. In the process of change, the ecological environment is damaged along with a large number of woodland, and grassland has turned into arable land and mining areas. The rapid expansion of human beings has destroyed the original large area of land to meet their own production needs, and it has caused damage to the ecological environment. Ecological environment restoration is carried out according to the type of land use. The types of land use change with the development of society; some land types develop towards a good ecological environment, and some develop in the direction of destroying the local environment. Via the land use transfer matrix and land use data, we can obtain the mutual transformation of land use types in the region. The land use transfer matrix can more clearly observe the transformation between different land use. According to the land use transfer matrix method and the land use data in 2017 and 2020,

Table 2. Land use transfer matrix (unit: square kilometers).

	2020	Arable Land	Pasture	Residential Land	Waters	Woodland	Unused Land	Total
2017
Arable land		28.882	4.289	5.185	0.599	0.699	0.011	39.664
Pasture		1.518	9.709	3.589	0.219	6.152	0.044	21.233
Residential land		1.522	4.574	98.348	0.490	1.029	0.065	106.029
Waters		0.195	0.079	0.317	11.846	0.041	0.005	12.484
Woodland		6.771	46.983	4.869	0.370	505.538	0.007	564.539
Unused Land		0.417	0.506	1.023	0.206	0.064	0.356	2.573
Total		39.306	66.140	113.332	13.731	513.525	0.488	746.522

is obtained. We can observe that 27.18% of the arable land in 2017 was converted to other land use types, of which 10.81% was converted to pasture and 13.07% was converted to residential land. In total, 54.27% of pasture land was converted to other land use types, of which 16.90% was converted to residential land and 28.98% was converted to forest land. In total, 10.45% of forest land was converted to other land use types, of which 8.32% was converted to pasture land. Part of the cultivated land is transformed into grassland and woodland, and some pastures are also transformed into woodland. Ecological land has increased and developed in the direction of good ecology. On the other hand, some woodlands and grasslands are transformed into other land use types and develop in the direction of ecological degradation. By analyzing the inflow and outflow between various land types in the transfer matrix, we can determine which areas need mine restoration and select the appropriate repair measures and targets. For example, if an area changes from woodland to cultivated land or now has exposed rocks, vegetation restoration may be needed; if an area changes from cultivated land to construction land, ecological reconstruction may be needed. According to the type of land use and local conditions, forest land restoration is carried out near the mine’s woodland, and grassland restoration is carried out near grassland.

3.2. Ecological and Geological Mine Environmental Problems

According to the NDVI trend map from 2011 to 2020, the overall vegetation growth trend of Tonghua City is smaller than the degradation trend, and the vegetation degradation in the mining area is also growing. Among them, vegetation degradation in Erdaojiang District is significant, and the reason for this is that most coal mining enterprises in Erdaojiang District were private small mines before integration, and they were relatively close, mostly with an annual output of about 5~300,000 tons of raw coal. These mines have the characteristics of thin coal seams and complex structures, which make mechanized mining difficult to promote. The result will inevitably lead to the expansion of the existing goaf collapse area in the area and generate new ecological geological and environmental problems. With the end of the restructuring of local coal mine resources in Tonghua City, local small coal mines will eventually be replaced, and the impact area of goaf collapse will be controlled.

Secondly, the economy of Tonghua City has been in a stage of rapid development since 2010, the demand for infrastructure construction in the region increased, and the non-metallic building materials required also increased significantly, which is bound to stimulate the continuous expansion of the production scale of building materials’ mining enterprises in the region and continuously increase mining intensity, resulting in the emergence of ecological geological and environmental problems in recent years. The development of clay and sand mines will further damage surface vegetation, aggravate land desertification, produce more waste residue, and induce geological disasters.

The price of metal ores is sensitive to policy and international forms, and some low-grade small metal mining enterprises in the region will be in a state of shutdown when prices are low. As the demand for metal ore grows, metal mines in the zone will be put into mining operations one after another, resulting in a long mining cycle for enterprises. Long-term mining has a negative effect on the environment; if these enterprises do not pay attention to environmental protection and sacrifice the environment to obtain resources, the resulting geological and environmental mine problems will be more prominent. For example, the waste rock produced by enterprises, unreasonable tailing residue stacking, the occupation and destruction of land vegetation resources, the heavy metal pollution observed in water quality caused by tailing waste liquid, aquifer damage caused by underground mining, and high potential energy tailing reservoirs are also facing the danger of dam failure, directly threatening the safety of downstream residents’ lives and property.

With the advancement of the integrated construction of landscape, water, forest, field, lake, grass, and sand, the next few years will be a key period for Tonghua City to implement ecological mine restoration, and it is necessary to avoid the aggravation of ecological geological and environmental mine problems.

3.3. Mine Recovery Governance Model Selection

The direction of mine restoration is usually cultivated land, forest land, and construction land, and the restoration method that is consistent with the surrounding landscape is selected; that is, the restoration principle of “suitable for cultivation, suitable for forest and suitable for scenery” is adopted. The remediation zoning process first determined the direction of remediation by using 10 m of land use data [20] produced by Esri in 2020 as a reference base map for the direction of mine remediation. With the mining area as the center, according to the results of field investigation and combined with land use data, if the surrounding environment of the mine is mountainous forest land or rural cultivated land, the restoration direction is set to restore forest land and cultivated land. Mines close to cities and towns need to be combined with urban development planning or as reserved land for construction projects, and the restoration method is divided into ecological reconstruction, in which mines with serious pollution need to be planned and constructed under the condition that the source of pollution is completely controlled and the possibility of secondary pollution is cut off. The determination of the direction of repair is the result of subjective human analyses and has certain limitations.

Secondly, the restoration of cultivated land and ecological reconstruction projects have economic benefits and do not fall into the category of natural restoration, and the process of restoring forest land needs to consider whether manual intervention or natural restoration means are used. After selecting the direction of the rehabilitated forest land of the mine, according to the NDVI time series change analysis results in Section 3.1, the trend of vegetation change within the mining area was used as the basis for judgment. When the number of rasters representing significant NDVI growth within the mining area is greater than the number of rasters indicating significant NDVI decrease, it is determined that the tenement area is suitable for the natural restoration of forest land; otherwise, it is determined that the mine area should use manual intervention restoration. The visualization is shown in Figure 6.

3.4. Mine Restoration Governance Cases

In recent decades, the greening of mines has become the main goal of China’s mining development. While improving the supply of resources, it is necessary to ensure the reclamation area of mine land and scientifically build a new pattern of green mines. Currently, China has basically improved the relevant standards and laws for the development of mining resources, and it is one step closer to the completion of a harmonious green mining development model of mines. The following are the cases of mine restoration and treatment projects in Tonghua City.

Land reclamation and the restoration treatment case of the Erdaojiang coal mine concentrated mining area in Wudaojiang Town at the Dalishugou mouth slope and bank land reclamation rectification: The reclamation area is about 9 ha, and the main ecological restoration measures are tree planting; the effect is better (see Figure 7).

Dongchang District quarry regreening restoration and treatment case in April 2007: There were 17 quarries in Dongchang District closed due to policy, and these mines were located along highways and around the city. In 2011, Tonghua City applied for the provincial mine environmental treatment fund of CNY 3 million, carried out ecological environment restoration projects for the Jiangnan Dolomite Mine and Jiangnan Quarry in Dongchang District, adopted high-order agglomerate spraying technology, sprayed and regreened the exposed slope, and used native tree species to repair mountains and heal injuries for mountains so that the original “white stubble mountain” changed its old appearance and improved the ecological value and landscape value of the mountain ecological environment. The north side of this green hillside is the Tonghua Science and Technology Cultural Center under construction, and the ecological restoration project of the mine added a lot of color to the main building that will be completed, which effectively improves the ecological environment of the mining area (Figure 8).

Due to the uneven thickness of the coal seam structure, the difference in the buried depth of the coal seam and the hydrogeological structure, and the influence of the different multi-layer mining sequences and construction progress, the time, speed, depth, and amplitude of the ground collapse of the wellfield are different such that the coal mining area forms a wave-like terrain and hilly landform of different heights. As a result of the damage to underground aquifers caused by mining, half of the traditional high-yield paddy fields in the subsidence area have been abandoned, and the other half experienced a sharp decline in production and increased costs. The ground collapse has attracted the attention of the local government, and in recent years, it has insisted on adapting measures to local conditions and scientific reclamation and has achieved some results. The local government took measures to relocate and avoid certain areas, turning residential areas into leisure and entertainment plazas, changing paddy fields to dry fields, and continuing farming operations, but crop yields were reduced from before the collapse. The road damaged by the collapse of the ground was renovated and hardened, but the quality of the road surface was greatly reduced compared to that before the collapse, and the road’s surface is bumpy.

4. Conclusions

In this study, Erdaojiang District and Dongchang District of Tonghua City, Jilin Province, were taken as examples, and the ecological environment restoration and governance model of their mining areas were studied. This study is combined with the ecological mine restoration work; most previous studies aimed at large mines, and there is basically no special research for this kind of small mine because some small mines are more suitable for natural restoration, and the damage is not too serious. In this study, the NDVI data of nearly ten years were selected, and the NDVI change trend chart is obtained by using Theil–Sen median and Mann–Kendall methods. The land use data from 2017 to 2020 were extracted, and the land use transfer matrix method was used to obtain the mutual transformation between different land use types. According to the distribution location of mining sites and land use types and according to local conditions, the surrounding environment of the mine is mountain woodland or rural cultivated land. The restoration direction is set to restore woodland and cultivated land. Mines near cities and towns need to be combined with urban development planning or as reserved sites for construction projects, and the restoration mode is divided into ecological reconstruction. After selecting the direction of the mine restoration of woodland, according to the results of the NDVI time series analysis, the vegetation change trend in the mining area is judged. Whether the mining area is suitable for the natural restoration of forest land or the artificial restoration of forest land is determined, and reasonable suggestions were proposed for the study of mine management models.

Under the principle of “suitable for cultivation, suitable for forest, suitable for scenery”, the problem of the mine restoration direction was solved; the problem of natural ecological restoration or the manual intervention of forest land in the process of mine restoration was solved; issues in the restoration and protection of priority areas were identified, and it was ensured all mine reclamation activities were carried out without worsening the damage to the ecological geological environment. This study is of positive significance for strengthening the protection of geological mine environments, speeding up the comprehensive management of geological mine environments, and carrying out research on the technology and methods of mine eco-geological environment protection and control. Generally speaking, production mines should first prevent and minimize disturbance and damage, perform repairs later, coordinate the entire process with the surrounding areas, and promote the coordinated development of resource development and environmental protection. The closure and restoration of abandoned mines should be coordinated with the surrounding environment or transformed and utilized, and a reasonable restoration and governance model should be adopted.