Land reshaping method of imitating natural geomorphology for open-pit mine dump in eastern grassland area of China

The eastern grassland area is a large-scale coal-fired power base dominated by open-pit mining in China. Due to its fragile ecological environment,the slope of the dumping site in open-pit mining is prone to landslide,subsid- ence and collapse. Therefore,the slope shape of dump is of significance to the protection of ecological environment and the sustainable development of mining industry. In order to explore a more scientific method for the slope shaping of open-pit dump,in this study,a normalized difference vegetation index (NDVI) and slope stability analysis are used to compare the effects of three slope shaping methods ( step type,slope type and wave type,which the wave type and slope type are designed by imitating natural landform) in the external dumping site of the Baori Hiller open-pit mine. The results show that ① the NDVI index of different shaped slope is wave type (NDVI = 0. 551) >slope type (NDVI = 0． 475) >step type (NDVI = 0. 340),but all of them are smaller than that of the surrounding natural topography,the plant growth of wave shaped slope is better than that of slope and step shaped slope;② the high step plant coverage is low. On the low step (650 m platform >660 m platform >670 m platform),the water loss of the low step slope is less than that of the high step;③ the slope stability is negatively correlated with the slope angle,and the stability of differ- ent shaping slopes is realized as wave slope type slope (F = 2. 711) >Slope type (F = 2. 513) >step type (F = 1． 073), the wave type and slope type slope are all within the safe range,and the step slope landslide is basically stable;④ the NDVI and stability coefficient of three types of slope shape have the same trend,the higher the vegetation coverage,the higher the slope stability. The wave-shaped shaping method of the natural dump of the excavation field outside the Bao- ri Hiller open-pit mine has the best effect.