Land Reclamation In Mining Areas Research Articles

Ecological environment quality assessment and spatial autocorrelation of northern Shaanxi mining area in China based-on improved remote sensing ecological index

The northern Shaanxi coal mining area is an important coal production base in China and an ecologically fragile area, and it is of great significance to explore the ecological environment quality and spatial evolution trend of the mining area. Based on Sentinel-2 and MODIS image data, an improved remote sensing ecological index was constructed by principal component analysis method: normalized difference vegetation index, normalized difference water index, normalized differential buildup and bare soil index, and net primary productivity. The ecological environment quality of the northern Shaanxi coal mining area and its influencing factors, as well as the spatial autocorrelation analysis of ecological environment quality, were discussed. The results showed that: 1) The vegetation coverage in the study area showed an overall increasing trend, but it was greatly affected by the average annual temperature. The NDVI index at the mine area is higher than the NDVI index at the non-mine area. 2) The water area gradually decreases with the year, which has a certain negative correlation with the total raw coal production. 3) The NDBB index showed a decreasing trend with the year, and compared with the non-mining area. 4) The coupling of year-by-year precipitation and temperature leads to interannual fluctuation of NPP value. 5) The change of ecological environment quality in the study area is the result of the comprehensive effect of natural factors and human factors. The implementation of ecological protection projects such as geological environmental protection and land reclamation in mining areas also has a certain impact on the trend of ecological environment quality. 6) There was a significant spatial autocorrelation in the quality of the ecological environment in the study area. There are significant “High-High” gathering areas of ecological environment quality within the coal mining area.

Quality evaluation of land reclamation in mining area based on remote sensing

Several deficiencies exist in the present evaluation of land reclamation quality in mining areas. These include the absence of an established set of evaluation index systems and standard acceptance criteria, as well as the use of traditional sampling techniques, which are costly and in efficiency, and time-consuming. Compared with the traditional sampling survey methods, remote sensing has the advantages of a wide detection range, diverse information collection, multiple data-acquiring strategies, high speed, and short cycle. In this study, we used the Xinzhuang coal mining field in Yongcheng, Henan Province as an example to extract information and invert surface parameters using remote sensing techniques, based on national and local reclamation regulations and standards. Subsequently, using remote sensing, we constructed an index system for evaluating land reclamation quality in three aspects: reclaiming project quality, soil quality, and ecological benefits. Through the grading standards of evaluation indicators and quantitative remote sensing models, we determined the extracted information on the area of indicators, roads, ditches, soil moisture, organic matter, and ecological benefits after reclamation. Based on this, we established a quality evaluation model for mining land reclamation using an improved index and method. The evaluation units were divided, and the weight of the evaluation index was determined using the analytic hierarchy process and data envelopment analysis (AHP–DEA) method. The land reclamation quality in the study area was comprehensively evaluated, field accuracy was verified, and the results were analyzed. The results show that, except for the removal of roads, houses, and fishponds in the study area, all 13 evaluation units achieved a score of 60 points or higher. The quality of reclamation met the standards, and the evaluation results were consistent with the conclusions of the field investigation and project acceptance report, demonstrating the reliability and feasibility of the method developed in this study. The research results will provide technical support for the scientific evaluation of land reclamation quality.

Land Reclamation and Governance in Dongda Mining Area

The south areaof Shandong Province is an important base of coal production in China. With the gradual depletion of coal resources, the destruction and abandonment of land in the mining area is very serious, greatly affecting the production and life of people around the mining area. The study of land reclamation and management in mining areas has become extremely urgent. In order to strengthen the reclamation and management of the land in the mining area, this paper, based on the current situation of the surface subsidence and land damage in the mining area of Dongda Coal Mine, and the analysis of the impact on the ecological environment, discusses the methods and measures of land reclamation in the mining area in detail. The findings of the paper will provide important insights into the surface subsidence and land reclamation and management in other mining areas.

Evaluation of Surface Crack Development and Soil Damage Based on UAV Images of Coal Mining Areas

Coal mining is necessary for the development of society but at the same time causes ecological damage that must also be repaired based on science. In the arid and semi-arid regions of northwest China, surface cracks are one of the major geo-environmental problems caused by coal mining, and studies are urgently needed to determine how to effectively repair them in a scientific manner. The rapid development of unmanned aerial vehicle (UAV) remote sensing technology in recent years has resulted in a good source of data for acquiring feature information on surface cracks. Existing studies mainly focus on high-precision crack extraction methods, and there are few studies on the methods for evaluating cracks. However, clarifying the degree of cracks requiring repair and what repair measures are required through scientific and reasonable evaluation methods is necessary to formulate effective crack repair and land reclamation plans. Given these considerations, in this study, the degree of both crack development and soil damage were evaluated based on the crack extraction results of UAV images. Based on the results of indoor experiments and field measurements, the grading criteria for the degree of crack development and soil damage were constructed. Crack density was used as the evaluation index for the degree of crack development (slight: <0.4%, moderate: 0.4–2%, severe: >2%). The distance between soil and cracks was the basis of the evaluation index for the soil damage degree (severe damage area: <0.6 m; slight damage area: 0.6–1.2 m; no obvious damage area: >1.2 m). Through the results from evaluating the degree of both crack development and soil damage in the study area, it was found that the degree of crack development was mainly moderate and located in the northern crack zone of the study area, with the cracks and damaged soil showing a striped pattern in the east-west direction. Combining the evaluation results of crack development and soil damage, the ecological restoration model of “natural restoration + crack filling + water supplementing + vegetation planting” is proposed. We conclude that crack repair should be applied in areas where moderate and severe cracks have developed, whereas soil repair should target the soil within 1.2 m of the cracks in the above area. This study is the first attempt to construct and evaluate the classification criteria of crack development degree and soil damage degree from the perspective of cracks and soil, and the results are of guiding significance for land reclamation in mining areas.

Causes and Countermeasures for the Failure of Mining Land Use Policy Reform: Practice Analysis from China

The current supply method of land acquisition for mining land in China is not conducive to the sustainable use of land resources, resulting in a large amount of wasted land resources and causing many conflicts. The new model of temporary land use policy for mining solves the long-standing problem of the livelihood of expropriated farmers that has plagued local governments, and also helps to alleviate the conflicts between enterprises and farmers. However, the temporary land use policy is in the practice stage, and the policy failure has resulted in low land reclamation rates. This research is a systematic survey for large and medium-sized mining enterprises, relevant government departments and research institutions nationwide. From the survey we analyze the problems in the implementation of the current temporary land use policy for mining and the causes of the policy failure, and propose an effective implementation mechanism for the future policy. The study showed that: (1) the temporary land use policy for mining was enacted with wide acceptance, but the implementation of the policy was ineffective; (2) the conditions for the application of the temporary land use policy for mining are unclear, the review and supervision by the competent authorities are not strict, and enterprises do not pay attention to land reclamation resulting in a very low rate of land reclamation; and (3) The implementation mechanism of the temporary mining land policy in practice is not perfect, and the proposed implementation framework based on “conditions, approval, implementation, supervision, acceptance and withdrawal” is scientific and feasible. It provides a reference for the management and innovation of strict protection of arable land, land conservation and intensification, and land reclamation in mining areas in China.

R-IMNet: Spatial-Temporal Evolution Analysis of Resource-Exhausted Urban Land Based on Residual-Intelligent Module Network

The transformation of resource-exhausted urban land is an urgent problem for sustainable urban development in the world today. Obtaining the urban land use type and analyzing the changes in their land use can lead to better management of the relationship between economic development and resource utilization. In this paper, a residual-intelligent module network was proposed to solve the problems of low classification accuracy and missing objects edge information in traditional computer classification methods. The classification of four Landsat-TM/OLI images from 1993–2020 for Jiaozuo city (the first batch of resource-exhausted cities in China) was realized by this method. The results (overall accuracy was 98.61%, in 2020 images) were better than the comparison models (support vector machine, 2D-convolutional neural network, hybrid convolution networks; overall accuracy was 87.12%, 96.16%, 98.46%, respectively) and effectively reduced the loss of information on the edge of the ground objects. On this basis, six main land use types were constructed by combining field surveys and other methods. The characteristics and driving forces of spatial-temporal change in land use were explored from the aspect of social, economic and policy factors. The results showed that from 1993 to 2020 the cultivated land, forest land, water body and other land types in the study area decreased by 690.97 km2, 57.54 km2, 47.04 km2 and 59.43 km2, respectively. The construction land and bare land increased by 839.38 km2 and 15.57 km2, respectively. The transfer of land use types was mainly from cultivated land to construction land, with a cumulative conversion of 920.95 km2 within 27 years. The driving forces of land use in the study area were analyzed by principal component analysis (PCA) and regression analysis. The spatial-temporal evolution of land use types was affected by policy changes, the level of social development and the adjustment in the economy, industry and agriculture structure. The investment in fixed assets and per capita net income in rural areas were the top two influencing factors and their cumulative contribution rate was 94.62%. The findings of this study can provide scientific reference and theoretical support for land use planning, land reclamation in mining areas, ecological protection and sustainable development in Jiaozuo and other resource-exhausted cities in the world.

Develop a Soil Quality Index to Study the Results of Black Locust on Soil Quality below Different Allocation Patterns

Mining areas are currently a typical ecosystem that is severely destroyed within the world. Over the years, mining activities have caused serious soil damage. Therefore, the soil restoration of abandoned mines has become a vital sustainable development strategy. The ecological environment within the hilly area of the Loess Plateau is extremely fragile, with serious soil erosion; Robinia pseudoacacia is the most popular tree species for land reclamation in mining areas within the Loess Plateau. To review the different various effects of Robinia pseudoacacia on soil quality below different configuration modes, this paper has chosen two sample plots within the southern dump of the Pingshuo mining area for comparison. The first plot is a Robinia pseudoacacia-Ulmus pumila-Ailanthus altissima broadleaf mixed forest, and the second plot is a locust tree broadleaf pure forest. The vegetation indicators and soil physical and chemical properties of the four stages in 1993, 2010, 2015, and 2020 were investigated. Principal component analysis is employed to develop the Soil Quality Index to perceive the changes within the Soil Quality Index over time. It is calculated that the Soil Quality Index of Plot I rose from 0.501 in 1993 to 0.538 in 2020, and Plot II rose from 0.501 to 0.529. The higher the SQI, the higher the reclamation of the mining area. It is found that Robinia pseudoacacia within the Robinia pseudoacacia-Ulmus pumila-Ailanthus altissima broadleaf mixed forest has higher soil quality improvement than the pure genus Robinia pseudoacacia broadleaf forest. This article can demonstrate the changes in the quality of reclaimed soil in the mining area, and can also provide a reference for the selection of reclaimed vegetation in other mining areas.

Spatial distribution of soil bulk density and its relationship with slope and vegetation allocation model in rehabilitation of dumping site in loess open-pit mine area.

Studies of soil bulk density (BD) spatial variations of land reclaimed after mining have become a focus of land reclamation and ecological restoration research. However, there have been few studies on the relationship among the reconstructed BD, terrain conditions, and vegetation growth. We examined the southern dumping site of the Pingshuo Antaibao open-pit coal mine located in a loess area in China. Field sampling data, digital elevation models (DEMs), and high-definition images were obtained, and indoor testing, geostatistics, and inverse distance weighting (IDW) were applied. This paper aims to analyze the spatial distribution law of the reconstructed BD and focus on its relationship with slope and vegetation allocation models. We demonstrated that (1) BD increased with soil depth and varied moderately within each layer. (2) The BD variation amplitude of the top 0-20-cm soil layer in both the east-west and south-north directions was small and more similar in the east-west direction than in the south-north direction, which was affected by herbaceous root systems. In the next four layers from 20 to 60 cm, the variation in BD in the east-west direction was far larger than that in the south-north direction, which was affected by vegetation classification. (3) On the whole, BD decreased with increasing slope, but when the slope was between 0° and 21°, BD exhibited a specific change law. (4) From the perspective of vegetation classification, the orders of magnitude of BD in the 0-20-cm and 20-60-cm layers differed. Overall, BD in areas vegetated with Korshinsk Peashrub was the lowest, and BD was moderate in areas with mixed vegetation, while BD was the highest in areas without vegetation or only vegetated with Black Locust. The mixed grass-bush-tree or bush-tree mode attained the best effect in regulating BD. These results can improve the basic principles of land reclamation in mining areas and provide a basis for further optimizing land reclamation technology in practice.

Tempo-spatial changes and main anthropogenic influence factors of vegetation fractional coverage in a large-scale opencast coal mine area from 1992 to 2015

The surface soil and vegetation had been destroyed by opencast mining, leading the decrease of the vegetation fractional coverage, which caused a severe damage to the mining area and ecosystems. However, land reclamation in mining area minimized the damage to the environment and was an important part of mine production and construction to improve the vegetation fractional coverage and restore the local ecological balance. To analyze the effects of anthropogenic activities on vegetation, the vegetation fractional coverage (VFC) and vegetation index (VI) of the whole Pingshuo opencast coal mine area from Shanxi province of China and four individual reclaimed dumps in this coal mine area were calculated respectively based on remote sensing images. The spatial distribution of vegetation fractional coverage was analyzed using Moran's Index. From 1992 to 2015, the vegetation fractional coverage of the whole coal mine area increased from 0.31 to 0.53, showing a benign development trend with significant change from 2000 to 2015, and it was the lowest in 2009. Moreover, The vegetation fractional coverage transformed from extremely low coverage, low coverage, to middle coverage, middle high coverage, and high coverage during 23 years, which was improved clearly. The long reclamation period is conducive to vegetation restoration, and the reclamation project has a direct effect and significance for the restoration of the ecological environment of the mining area. The vegetation fractional coverage of four dumps in the study area were the lowest at the initial reclamation time, and increased with increasing reclamation time. The vegetation coverage of the Southern dump, Western A dump, Inner dump and Western B dump increased from 0.29 to 0.68, 0.34 to 0.59, 0.5 to 0.76, and 0.46 to 0.54, respectively. The increase of the global Moran's Index from 0.80 to 0.91 indicated that the spatial agglomeration was greatly influenced by anthropogenic activities from 1992 to 2015. The local Moran's Index showed that the vegetation fractional coverage of the whole stage was mainly high-high clustering and low-low clustering in 2015, and the vegetation fractional coverage of the dumping sites changed from the original low-low clustering to high-high clustering from 1992 to 2015. The area was heavily affected by both mining and reclamation, the vegetation fractional coverage of the dump site was significantly improved after reclamation.

RETRACTED ARTICLE: Suitability evaluation for land reclamation in mining areas: Gol-e-Gohar Iron Ore Mine of Sirjan, Kerman, Iran

AbstractSuitability evaluation plays an important role in the land reclamation. This paper deeply elaborates the goal of land reclamation of Gol-e-Gohar Iron Ore Mine and the principles of suitability evaluation. This was divided into four evaluation units that were assessed, respectively, by selecting evaluation factors. According to the destruction forecast, the destroyed land includes four parts: open-pit slope, open-pit bottom, dump slope and the land for roads. We developed an improved method, i.e. limit comprehensive conditions method, based on the current research achievements. The results show that the proposed method is more applicable and easier to handle.

Zoning of land reclamation in coal mining area and new progresses for the past 10 years

Coal mining disturbed land is the main sources of land reclamation in China. With the rapid increase of economy and coal production, more and more land has been disturbed by construction and coal mining; thus, land reclamation has become highlights in the past 10 years, and China is boosting land reclamation in mining areas. Disturbance characteristics vary from region to region, according to natural and geological conditions, coal mining area land reclamation was divided into 3 zones, which are eastern, western and southern. Reclamation strategies are focused on prime farmland protection in eastern and ecological restoration in western and southern zones, respectively. Several innovative reclamation technologies and theories for the past 10 years were introduced in this paper, including concurrent mining and reclamation, Yellow river sediments backfilling, self-reclamation, and topsoil alternatives in opencast mines. Besides, in the government regulation and legal system building respect, several important laws and regulations were issued and implemented in the past 5 years, promoting land reclamation management and supervision greatly. Land reclamation is and will still be one of the most important parts of coal industry in the future, and more efforts and funds are expected to get involved.

The Index System and Methods of Monitoring Damaged Cultivated Land Quality in Mining Area Based on Agricultural Land Classification

Damaged cultivated land reclamation in mining area is one of the important ways to remediate the cultivated land in China. In the study, Index system of monitoring damaged cultivated land quality in mining area was established on the basis of agricultural land classification indexes. Collapse depth, excavation depth, cover occupation height, density of fractures, and the additional slope are added to reflect the characterization of micro topographic. Methods which are used to monitoring damaged cultivated land quality are summarized according to the condition of mining area. The connection between gradation of agricultural land (upper level) and damage level (lower level) is established. These measures could make the results of land reclamation management effectively and directly serve the update of agricultural land grading results.

Changes of landscape ecological quality for land reclamation in mining area

Changes of landscape ecological quality for land reclamation in mining area

Suitability evaluation for land reclamation in mining area: A case study of Gaoqiao bauxite mine

Suitability evaluation plays an important role in land reclamation because the choice of evaluation methods affects the accuracy and objectivity of the suitability evaluation results. Furthermore, it influences the decision-making related to land reclamation. An improved method, which is called limit comprehensive conditions method, was developed after different suitability evaluation methods were studied. Based on this method, the reclaimed land of the Gaoqiao bauxite mining area was evaluated. The Gaoqiao mining area was divided into seven evaluation units that were evaluated respectively by selecting evaluation factors and establishing grade standards. The results show that the proposed method is more applicable and easier to handle. Moreover, its evaluation results are more scientific compared with the traditional evaluation methods. The improved method can be beneficial to the rapid monitoring and the effective management of reclaimed land in the opencast mine area.

Management of topsoil for geo-environmental reclamation of coal mining areas

Topsoil is an essential component for land reclamation in mining areas. It is seriously damaged if it is not mined out separately without being contaminated, eroded and protected. Systematic handling and storage practices can protect topsoil while in storage and after it has been redistributed onto the regraded area. Impact of coal mining on topsoil quality in Indian context has been described. Systematic removal of topsoil, its storage practice, geometry of topsoil heap are discussed in this study. Removed topsoil should be reclaimed technically and its shelf-life period should be ascertained. To assess the shelf-life period, an investigation was conducted in a large opencast coal project. Soil dumps of different age classes in the area were identified and analyzed critically to evaluate the deterioration of soil quality with respect to time, and compared with those of unmined areas. Changes in soil quality showed a continuous decrease every year and ultimately became biologically sterile. Biological reclamation is essential if the soil is to be stored beyond the shelf-life period. Preservation of stockpiled topsoil, its redistribution on the regraded areas, nutrients and amendments to be added, are discussed briefly in this study.