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With the increasing proportion of open-pit coal mining in the coal mining industry in China, a series of potential safety hazards, environmental pollution, ecological damage and other problems caused by open-pit coal mining have attracted a great deal of attention. Scientifically determining the appropriate mining right scope of an open-pit coal mine can prevent various problems caused by coal mining from the source. In this study, according to the characteristics of open-pit coal mining and the environmental characteristics in arid areas, 15 indicators were selected and their weights were determined from the three perspectives of geological environment, social environment and ecological environment by using the AHP. Based on the spatial analysis function of ArcGIS, a digital evaluation model was established for the corresponding influencing factors, and a comprehensive evaluation model for setting the mining right range was constructed by superimposing the weights. Finally, four mining areas were identified within the study area in Wuhai, Inner Mongolia, and their ecological values were calculated to determine the mining area with the lowest ecological impact. [ABSTRACT FROM AUTHOR]

In order to clarify the ecological restoration direction, this study investigated the limiting factors of the ecological restoration of the dump of Rujigou Open-pit Coal Mine in the Helan Mountain Nature Reserve from the aspects of climate, topography, and soil physicochemical properties. The main results are as follows: (1) In terms of climate, the main limiting factors in the study area were low precipitation (<200 mm) with uneven annual distribution, high evaporation (2000 mm), low temperature, less effective accumulated temperature, and large number of gale days (≥150 days). (2) The topographic limiting factors were steep slope (30°–36°) and long slope length (10–44 m). (3) In terms of soil, the main limiting factors were high contents of sand (73.40%±2.18%) and clay (13.21%±1.37%), low porosity (30.89%±0.83%), and low contents of total nitrogen (0.67±0.05 g kg–1), hydrolytic nitrogen (14.23±0.48 mg kg–1) and available phosphorus (2.81±0.44 mg kg–1). The limiting factors of the ecological restoration of the study area mainly included drought and water shortage, less effective accumulated temperature, large number of days of strong wind, steep slope, long slope length, and soil depletion. In view of the above limiting factors, countermeasures such as slope foot support, slope level arrest and consolidation, slope cover, plant measures, and muck improvement can be considered. This study provides a scientific basis and theoretical support for the selection of appropriate ecological restoration measures and improvement of restoration effectiveness for open-pit mine dumps in arid areas such as the Helan Mountains. [ABSTRACT FROM AUTHOR]

While promoting economic and social development of China, open-pit coal mining will also cause irreversible harm to the surrounding environment due to disturbing the topsoil. Therefore, ecological restoration measures are urgently required. Vegetation cover is an important part of mine ecological restoration work. Suitable soil structure and nutrient conditions are the basis of normal plant growth and development. In this study, the slag, sand, humic acid, diammonium phosphate (DAP) and urea were selected as the improved materials to adjust the structure and fertility of the slag and improve the slag into a suitable vegetative substrate for plant growth. From among various configurations of the vegetative substrate, the most suitable substrate for plant growth was filtered by comparing the physical and chemical properties and their effects on Alfalfa growth under different treatments. The results showed that the application of fertilizers could increase the nutrient content of the vegetative substrate and increase the pH, but the growth of Alfalfa was not optimal under the high fertilization treatment. The addition of sand could mitigate the structural problems of slag, and sand also showed a certain degree of regulation on fertility. Moreover, the addition of appropriate amounts of humic acid can enhance slag maturation and stabilize the chemical properties of the vegetative substrate. According to the results, the most optimal slag-sand-humic acid ratio for the vegetative substrate of the dump site of the Dafeng Open-pit Coal Mine is 18:1:1. The findings are expected to offer a reference for the improvement method of slag in this area, which alleviates the shortage of soil resources. It provides support for ecological environmental protection in soil source area, and also offers a new idea for the resource utilization of slag in the ecological restoration. [ABSTRACT FROM AUTHOR]

In order to study the counterpoint configuration about the types of mining sites and ecological restoration technologies, open-pit coal mine dumps that had been ecologically restored, since many years, in the grassland mining area in western Inner Mongolia, were selected. A comprehensive evaluation of slope protection effect, vegetation restoration effect, soil improvement effect and engineering technology cost was carried out in order to classify the types of sites for open-pit coal mine dumps and to determine their counterpoint ecological restoration technology, so as to provide theoretical guidance and technical support for ecological restoration of the grassland mining area in western Inner Mongolia. The research results are as follows: (1) Soil thickness, slope gradient and slope aspect are the dominant factors affecting the site conditions of the dump site. Base on this, the dump site of the open-pit coal mine in the grassland mining area of western Inner Mongolia was divided into 9 types of sites. (2) For half-shade and half-sunny to thick soil gentle slope, we primarily recommend plant grid slope protection + planting + sowing + sprinkler irrigation, and the second recommendation is hexagonal brick slope protection + mortar masonry ditch + sowing + sprinkler irrigation; for half-shade and half-sunny to medium-thick soil gentle slope, we primarily recommend masonry skeleton slope protection + mortar masonry ditch + sowing + sprinkler irrigation, and the second recommendation is sowing + vegetation blanket coverage + sprinkler irrigation; for half-shade and half-sunny to thin soil gentle slope, it is recommended to use gravel capping + mortar masonry ditch. For sunny thick soil gentle slope, we primarily recommend eco bag blocking + planting + sowing + vegetation blanket coverage + sprinkler irrigation, and the second recommendation is eco bag blocking + sowing + grass curtain coverage grass curtain coverage + sprinkler irrigation; for sunny thick soil steep slope, it is recommended to use plant grid slope protection + mortar masonry retaining wall + sowing + sprinkler irrigation. For shade thick soil gentle slope, we primarily recommend eco bag blocking + planting + sowing + vegetation blanket coverage + sprinkler irrigation is preferred, and the second recommendation is planting bag stacking + mortar masonry retaining wall + sprinkler irrigation; for shade medium-thick soil gentle slope, it is recommended to use eco bag blocking + corrugated pipe drainage + sowing + vegetation blanket coverage + sprinkler irrigation; for the shade medium-thick soil steep slope, we primarily recommend eco bag blocking +sowing + grass curtain coverage + sprinkler irrigation, and the second recommendation is eco bag blocking + corrugated pipe drainage + sowing + vegetation blanket coverage + sprinkler irrigation. For thick soil platform, use of planting + sowing + sprinkler irrigation is recommended. The research results provide a scientific basis for selection of ecological restoration technologies in the grassland coal mining area in western Inner Mongolia. At the same time, with respect to the semi-arid grassland mining area with relatively fragile habitats, this research be of great significance to improve the greening benefits of the mining area and for improving the mining area and surrounding ecological environment. [ABSTRACT FROM AUTHOR]