The optimal framework and model to balance underground coal mining and cropland protection in Jining, eastern China

Coal and cropland resources play a vital role in energy safety and grain supply, respectively. However, the social growth that is driven by coal mining is followed by cropland damage, reductions in grain yields, and human-land conflict, all of which impede the sustainable development of coal mining and food safety. Thus, finding a way to optimize both coal mining and farmland protection in the coal-cropland overlapping area is crucial. In this paper, we constructed theoretical and empirical models to analyze the impact of the working face width on cropland with non-full subsidence based on the extent of cropland damage due to land subsidence caused by mining. Taking the Jining Coalfield with its high groundwater table as an example, this critical land subsidence was discussed based on the groundwater level (reclamation timing), suitable groundwater depth of crop growth, and coal mining efficiency. In addition, the reasons for surface ponding were analyzed caused by underground coal mining. The results showed that the surface ponding's anthropogenic item and internal factors are mining-induced land subsidence and the high groundwater table, respectively. These joint factors raise the groundwater level and lead to grainland damages which can be divided into four categories based on their extents (no effect, slight-reduction in yield, moderate-reduction in yield, and no harvest). Critical subsidence caused by mining width could optimize the groundwater depth or cropland damage. The calculated results from both models of the eight coal mines showed that the average mean deviation was 3.93%. The calculated results from the models were reliable, while the empirical model had fewer parameters and an easily calculable simple formula. The proposed optimal framework verified that the mining width needed to be reduced to 134m, 126m or 116m, 112m based on the groundwater depth or the damaged farmland in the Xinglongzhuang Coal Mine. The optimal framework will be of great significance for providing scientific references as to why the sustainable development of coal mining and grainland protection has been chosen.

Automated summary

This study analyzed the impact of coal mining on cropland and proposed key issues in optimizing coal mining and farmland protection. By examining the influences of various factors on surface ponding and cropland damage, recommendations to reduce mining width were suggested to achieve sustainable development.