Geological soil formation for ecological restoration of mining areas and its case study

Soil is an important substrate of plant growth, as well as the key for successful ecological restoration of mine. In view of the status of insufficient soil for most of ecological restoration of mine and the reality of a very long process of geological soil formation, the concept and method of geological soil formation for ecological restoration of mine (Mine-GSF for short) were discussed on the basis of description on the principle of natural geological soil formation. Natural geologic soil formation is the process of turning “rock” into “soil” through a long period of macro-geological cycle and biological cycle, including the important links of weathering, claying, accumulation of organic matter, and the exchange and migration of elements. Mine-GSF is the process of simulating the natural geological soil formation by promoting the rapid development and maturation of soil with the physical, chemical and biological measures through screening the available soil-forming parent materials or soil materials at the mine site, and thus forming the desired soil functions in a short period of time to achieve a self-sustainable development state. It is exactly a process of artificial soil formation. Specifically, the method consists of four steps: demand analysis of Mine-GSF, screening of parent material for soil formation, composition of soil materials and its biological maturation. In addition, the relationship between Mine-GSF and soil reconstruction for mine reclamation was described. Moreover, the geological soil formation process for the topsoil of open pit mine based on the original soil material of geological stratums is discussed in detail, and the optimal soil material composition and biological maturation method with the third layer of original soil as topsoil was determined based on the ecological restoration of an open pit coal mine in Inner Mongolia. The method of coal-based biological soil constructed on the principle of geological soil formation is introduced using the solid waste of mine as the soil material. Meanwhile, prospect is made for the application of geologic soil formation with the Yellow River sediment as soil material in the ecological restoration of western mining areas.