A seasonal changes-based equilibrium strategy for coal–water conflict: a case study at the Yanzhou coal field

Groundwater damage and pollution are now becoming the main obstacles to sustainable development for large-scale coal fields. In this paper, an equilibrium strategy-based bi-level optimization model under uncertain conditions is proposed to deal with such obstacles. The aim of the model is to establish an environmental protection-based mining quota competition mechanism to achieve sustainable development in Chinese large scale coal fields by fully considering the relationship between the local authority and the collieries as well as the influence on coal mining activities caused by the changing of the seasons. To deal with inherent uncertainties, the model is defuzzified using a combination of the fuzzy expected value and possibility measure and, to search for the solutions, an approach based on the Karush-Kuhn-Tucker condition is designed. The successful use of this model on a real world case demonstrates its practicality and efficiency. Sensitivity analyses under different constraint violation risk levels are also implemented. The results show that under an environmental protection-based mining quota competition mechanism, the collieries attempt to conduct environmentally friendly exploitation to seek greater mining quotas. Thus, demonstrating the guidance this model can provide to ensure sustainable development. Finally, by analyzing the results, some conclusions are provided to serve as the foundation for the proposed policy recommendations.