Zhenqi Hu

A study of land reclamation and ecological restoration in a resource-exhausted city – a case study of Huaibei in China

Eco-city construction is a powerful method which can advance a city from traditional industrial civilisation to ecological civilisation. The city of Huaibei, with 50 years of coal mining history, has been listed as a national resource-exhausted city. The citys sustainable development and ecological restoration work face severe challenges. This study presents a time-space evolution analysis of mining subsidence to show the evolution and the distribution of the subsidence area in Huaibei. Intensive use was made of land evaluation to formulate land use measures. According to this analysis, and based on the popular eco-reconstruction movement, suggestions for land reclamation and eco-reconstruction are proposed for the city of Huaibei. The paper aims to make strategic recommendations to help Huaibei city transform from a resource-exhausted city to an eco-city.

Dynamic subsidence simulation and topsoil removal strategy in high groundwater table and underground coal mining area: a case study in Shandong Province

Coal mining in high groundwater table areas causes many environmental issues. In China, such regions have three unique and significant characteristics, (1) multiple coal seams; (2) thick coal seams and (3) high groundwater, which lead to mine subsidence ponds. In the past, reclamation of disturbed land was carried out after subsidence stabilised. Such reclamation is a low-percentage of reclaimed farmland, and has high reclamation cost, difficult construction conditions, because of relatively flat terrain and the shortage of backfilling materials in flat topography. Therefore, salvaging the topsoil before it is submerged in water and reusing it while subsidence becomes stable would be a good way to improve the reclamation efficiency. This paper considers a longwall panel in Shandong province as a case study. Dynamic mining subsidence was simulated using mining subsidence prediction software. To illustrate subsidence development and its effects on farmland, the ground was first divided into cell size of 40 m along with pre-mining topography. The mining subsidence and water logging time for each cell were then calculated. Based on the simulations, the topsoil removal time, scope and depth of topsoil was determined. The salvaged topsoil could be reused subsequently, which would provide enough filling material to raise the percentage of reclaimed farmland, and reduce reclamation costs. The research benefits the development of concurrent mining and reclamation technology in underground mining sites, and promotes the synchronisation of exploitations and treatments.

Improved methods for fuzzy comprehensive evaluation of the reclamation suitability of abandoned mine lands

Abstract Division of evaluation units and establishment of membership functions are two key steps of fuzzy comprehensive reclamation suitability evaluation of abandoned mine lands. This paper improves both the method of evaluation units division and the method of membership functions establishment. Empirical research is carried out in Mentougou district of Beijing in China. It shows that as a mountainous area, among the 603.79 hm2 abandoned mine lands in Mentougou, highly and moderately suitable area for agriculture use are only 54.99 hm2 and 80.00 hm2. Lowly suitable area is 468.80 hm2. This research can provide theoretical support for the practice of abandoned mine lands reuse.

Ecological restoration plan for abandoned underground coal mine site in Eastern China

Eastern China has a long history of coal mining and a large number of coal mine sites have been abandoned in this region leaving a legacy of mining-related land subsidence, coal waste piles and brownfield sites. Furthermore, as a result of the historical planning approach in the region, many cities were built around coal mines. Therefore, the ecological restoration of abandoned mine land has become vital to the sustainable development in these cities. This paper uses the Datong coal mine site in Huainan as a case study to develop a detailed ecological restoration plan and functional division for an abandoned underground coal mine land by considering the local conditions and mining history, site assessment and integrated monitoring tools.

Visualisation of the characteristics of mining subsidence with the consideration of topography: a case study in China

The existing three-dimensional visualisation of mining subsidence cannot fully convey the original landscape in the mining area. By using GIS and coupling the predicted result of subsidence in different mining stages with the original elevation data, a dynamic visualisation of mining process is approached, which could reflect geomorphologic features clearly. Furthermore, it visually shows the variation and the characterisation of the surface subsidence, according to which one can analyse and evaluate the degree of mining subsidence damage. The generated information, such as slope, aspect, stagnant water area and the amount of settlement volume calculation, could provide technical support for reclamation work while mining is in process.

Mitigating mine subsidence dynamically to minimise impacts on farmland and water resources: a case study

Subsidence related to underground mining can negatively impact farmland and water resources. This paper has developed dynamic subsidence reclamation (DSR-reclamation concurrent with mining) approaches to minimise these impacts and are illustrated using a case study in China. Two reclamation plans using DSR and traditional reclamation (TR-reclamation upon completion of all mining) approaches were designed respectively. Then farmland utilisation, water resources development and cost-benefit analyses were performed for the two sets of plans. The results show that farmland and water resource utilisation by DSR is larger than TR throughout the mining period. Farmland utilisation by DSR increased as much as 12.94%. Similarly, final water volume by DSR was 15.01% more than TR. The total revenue using DSR increased by 24.17% as compared with TR over a ten year period. So, DSR can be a very positive and cost effective approach for protection of farmland and water resources.

Ecological Restoration in the Typical Areas

Human activities are strongly regional and targeted, and usually tightly bound to the regional natural resources, the needs of social economic development, and ecological fragility, which cause typical regional ecosystem degradation problems. For serious degradation areas, it is an effective way to carry out regional ecological restoration and construction for restoration ecology study, which is the key to promote sustainable development and ecological security, and also the urgent requirement for the current reality. According to the demand of regional sustainable development, this chapter focused on ecological deterioration, and restoration and construction in typical areas. The chapter specially made thematic discussions on new progression in degradation problems of developing and utilizing the resource, ecological restoration practices, theory, techniques, mode, and management. This chapter was trying to provide experience and lessons, macro guidance and decision-making reference for ecological restoration in typical areas. From the regional cases of this chapter, we can see that regional ecological restoration and construction is intricate. Finally, it is necessary to point out that there are many regional ecological restoration cases, here just introduce several cases in western fragile region. The ecological restoration cases revealed in this chapter are just the first attempt to conclude the past experiences in China, which are initial identification for correlated theories and methods.

Introduction to Concurrent Mining and Reclamation for Coal Mines in China

Mining subsidence land reclamation was focused on stable land for the past 30 years in China. In eastern China, a relatively flat terrain and high groundwater table area, mining activities cause more than half of the subsided land submerged in water and the fertilized top soil was lost permanently, which leads to a low percentage of farmland reclamation and inevitably increases the reclamation cost. In this paper, a new technology and innovative concept of Concurrent Mining and Reclamation (CMR) was proposed, and its principles and key technologies of CMR for underground coal mining were presented. The advantages with high reclamation percentage of land resources for the new technology were proved based on a case study; CMR could increase farmland reclamation percentages to 37.59%, compared with the farmland reclamation percentage of post-mining. The scope and prospects of application of CMR were also discussed. CMR could be used in 5 of the 14 large coal bases in China. It is estimated that the application of CMR could increase land area by 6680.9 km2.

GIS–based pre–mining land damage assessment for underground coal mines in high groundwater area

Coal mining cause different degrees of damage to both land and ecosystems. Evaluation of disturbed land is a fundamental and prerequisite work for land reclamation and rehabilitation. However, most of those evaluations were carried out when mining was under process or after it cease. This paper proposes an innovative assessment model for pre–evaluation which could be implemented before mining activity begins. A geographic information system (GIS) was constructed to evaluate land damage. Three natural condition factors and three geological condition factors were chosen for evaluation. The results show that: land damage was categorised as five degrees, which are negligible, slight, moderate, severe, and very severe. Furthermore, very severely damaged areas are mainly concentrated in the northwest part of the coal mine, whereas slight damaged areas are mainly concentrated in the southwest. The developed coupling technique was used to forecast land damage, and provide reference for reclamation work.

Abandoned land reclamation planning in coastal area in North-East of China

The damaged environment is a global problem. It is more serious in China because of the cultivable land destroyed. So the agroecosystem reconstruction is the primary object in China. A case of reclamation planning in LiaoNing Province was studied in this paper. A large number of abandoned land sites have become an urgent task for the local government since farmland is so short in this area. The land suitability and usage should be determined before the land reclaimed. Based on land-use mathematical models and software MATLAB 6.0, optimum land-use structure should fit for local ecological and economic requirement. The horizontal, vertical structure and food chains of the system should be considered. Ecological engineering was used to planning as the shelter-forest, farmland and livestock farms. Irrigation work was designed to remove the salt. The forestry, fishery, poultry breeding were set up after rehabilitation. Therefore, the regional environment can get a great progress and their economy will have a sustainable development. Additional