Differentiation and mechanisms on physical properties of reconstructed soils on open-cast mine dump of loess area

Soil reconstruction on the open-cast mine dump is an important part of land reclamation. This study took soils at the south dump in Antaibao open-cast mine of China Coal Pingshuo Group as the research object and focused on analyzing the physical properties and differentiation mechanisms of the reconstructed soils collected from the dump along the slope and platform of shady slope, half shady slope, sunny slope, and half sunny slope of the open-cast coal mine at the overall level, site level, and terrain level, respectively, during the soil-rock mixture discharge process. The results are following: (1) the variation coefficients of soil bulk density, soil porosity, soil mass water content, as well as soil gravel content are at a state of medium variability. (2) After a long time of vegetation restoration, soil bulk density is decreased, soil porosity is increased, and soil mass water content quality is improved. (3) The physical properties of reconstructed soils at platform are slightly, but not significantly better than those at slope. (4) Most physical properties of the reconstructed soils are significantly different at the slope and aspect levels, but not at the altitude level. (5) At the slope level, the physical properties of reconstructed soils are significantly different between the moderately steep slope and high steep slope. (6) At the aspect level, soil bulk density, soil porosity and soil gravel content sunny slope are obviously different from those at half sunny slope, and soil mass water content at shady slope is significantly different from that at half shaded slope. Lastly, we proposed some specific measures to optimize land reclamation technologies.