Analysis on the coupling coordination of resource-environment-economy of coal industry: a case of Yulin City

The measurement of coupling coordination level is of great significance for the study of sustainable development of coal industry. According to the coupling mechanism of the resource-environment-economy (REE) system of coal industry, the evaluation index system was constructed. The evaluation values of coal industry REE system as well as that of each subsystem were calculated by entropy weight method and TOPSIS method. The coupling coordination degree was calculated by the coupling coordination degree model to evaluate the coupling coordination level of coal industry REE system. The results showed that the comprehensive evaluation value of coal industry REE system in Yulin City showed a "U" type trend, which was similar to the evaluation value of environment subsystem and had an obvious improvement. The coupling coordination level of coal industry REE system had been continuously optimized and was in the coordination range, showing a steady-downward-upward trend. The coupling coordination degree was 0.86 in 2018, reaching a good coupling coordination level.