Reuse ways selection of abandoned open pits based on inference conditions and rules

Abstract: Abandoned open pits are leftover waste lands after the closure of open-pit mining, and their number and size continue to increase. They have destroyed large quantities of land in the form of excavation and have different degrees of negative impact on ecological security and landscape. Therefore, under the serious population-land-economy contradiction background in China, the reuse of abandoned open pits is necessary and is an important aspect of green development and circular development. In order to better reuse abandoned open pits, the existing case studies of abandoned open pits reuse were summarized and were divided into agricultural production pattern, ecological conservation pattern, tourism entertainment pattern, science education pattern and social service pattern, and each reuse pattern included different reuse ways. Then a method of selecting reuse ways from the perspective of constraints was constructed, which was based on inference conditions and inference rules. The method selected 3 categories of restrictive conditions, which were open pit conditions, natural conditions and other conditions. To be specific, open pit conditions included size, pollution, slope stability, water accumulation in pit, depth and slope; natural conditions included solar radiation, dominant wind direction, irrigation and soil source; other conditions included traffic, distance from settlements, labor resources, technology, ideology and culture, public participation, and regional position relative to urban. Through expert consultation, literature extraction and specification inquiry, 58 inference conditions and 13 inference rules of reuse ways were formed. At last, the restrictive conditions were divided into permanent restrictions and temporary restrictive conditions. The former had strong restrictions while the latter had weak restrictions. The inference order was proposed according to principles of "permanently restrictive conditions first", "strongly restrictive conditions first", by which some strongly restrictive reuse ways could be ruled out quickly. Applying the method, reuse ways of 3 open pits in Pingshuo coal mine were selected. The results indicate that: (1) The method based on inference conditions and inference rules can select reuse ways of abandoned open pits. (2) By a preliminary inference, the study area can be used as ecological conservation area, refuse landfill, tourism entertainment area and photovoltaic power generation base, and in the decision-making process, these 4 types of reuse ways for 3 pits can be combined and coordinated to realize comprehensive reuse, considering the existing reclamation landscape, industrial planning, land use planning and economic conditions. (3) The decision result needs more detailed analysis and appraisal of multiple schemes, which is usually a subset of the inference results, may also be empty. The research can provide a reference for the reuse of open pits which have been closed or will be closed. However, the reuse of abandoned open pits is a complex and huge system, involving a variety of subjects and fields such as mining, geology, agriculture, forestry, environment, ecology, landscape, architecture and engineering. Therefore, conditions in this paper may need to be supplemented. In addition, this research is mainly based on reuse ways that are existing or in research worldwide. In practice, we can refer to it, and can go beyond the scope of this study as well.