The Sustainable Impact of Coal Mining on Water Utilization Efficiency in the Shengli Mining Area

The surface disturbance caused by coal mining and the ecological restoration have changed the vegetation coverage and ecosystem functions of the Shengli mining area. This disturbance has affected the carbon and water cycles, resulting in complex response characteristics of water use effectiveness (WUE). To reveal these response characteristics, this paper uses multi-source remote sensing data from 2001 to 2024 and applies random forests to scale down MODIS 500 m net primary productivity (NPP) and MODIS 1 km evapotranspiration (ET) to 30 m resolution. Then, it calculates the WUE of the Shengli mining area to reveal the temporal and spatial variation patterns and characteristics of WUE in the mining area and the spoil dump. It also uses the Pearson correlation coefficient to analyze the driving factors of WUE. The results show that the determination coefficients R 2 of the NPP and ET scaling models are 0.961 and 0.7142 respectively. The WUE in the study area and four spoil dumps from 2001 to 2024 all follow the pattern of “decrease due to disturbance—recovery and rise—gradual stabilization”, with the peak WUE in the mining area reaching 1.123 g·C·m −2 mm −1 in 2002, a fluctuation decline from 2002 to 2011 with a valley value of 0.398 g·C·m −2 mm −1 in 2010, an annual increase trend from 2011 to 2013, and a basic stabilization from 2013 to 2024, with an average value of 1.001 g·C·m −2 mm −1 during this period. Compared to the average value of 1.061 g·C·m −2 mm −1 from 2001 to 2022, WUE has not yet returned to the initial level. The Pearson correlation coefficients ranked from high to low are: NDVI (0.59, +) > | deformation (−0.39, −) | > temperature (0.27, +) > rainfall (0.26, +) > mining area (0.072, +), indicating that NDVI and deformation are important factors affecting WUE. Further analysis of the relationship between NDVI disturbance and WUE reveals that the mean NDVI disturbance and recovery in the study area from 2001 to 2024 are 0.438 and 0.392 respectively. WUE shows a “first decline—then rise—then stabilization” phased evolution pattern during the “disturbance—recovery—stability” process of vegetation, and the disturbance intensity and recovery intensity are positively correlated with the rate of WUE decrease and increase. The combination analysis of deformation and WUE indicates that the deformation areas in the mining area and the inner spoil dump show a trend of WUE reduction due to the increase in deformation volume. The study shows that the continuous mining of open-pit coal mines continues to affect the water usage function of vegetation in the mining area. Subsequent restoration should prioritize strengthening surface stability, soil water retention, and vegetation reconstruction in the mining area, inner spoil dump, and areas with large deformation to improve the stability and water usage efficiency of ecological restoration.