Dynamic Evaluation of Water Utilization Efficiency in Large Coal Mining Area Based on Life Cycle Sustainability Assessment Theory

Abstract

Coal mining enterprises have a variety of water sources, complex drainage structures, long production chain, and many links, which lead to uncoordinated water utilization and low water efficiency. Taking a large coal mining area of China as an example, a dynamic model was established to evaluate the water utilization efficiency based on the Life Cycle Sustainability Assessment (LCSA) theory. In the model, the influence of five aspects (including resources, economy, technology, society, and environment) and 19 factors was considered. The game theory method was adopted to calculate the fusion weights of the 19 factors according to the analytic hierarchy process and CRITIC method. The CW-VIKOR method was used to explain the dynamic evaluation results of water efficiency in the coal mining area. The results show that the environmental impacts of the mining system mainly come from three aspects: regional drainage, domestic sludge landfill and disposal, and water system electricity consumption. Electricity consumption in water systems has the greatest environmental impact, accounting for about 73%, regional drainage for about 26%, and domestic sludge landfill and disposal for about 1%.The CW-VIKOR approach can harmonize the interrelationships among resources, economy, technology, society, and environment. It is an effective method for LCSA of water resource in the coal mining area. The reliability of the evaluation results is high and close to the actual situation. The dynamic model established in this paper is also applicable to other coal mine areas, and only the factor weights need to be modified according to the specific characteristics of each coal mine. The model can provide guidance for optimal exploitation and allocation of coal mine water resources.