## 4 Discussion  
This study utilized various methods, including trend analysis, coefficient of variation (CV), and Hurst Index, to analyze NDVI data in the Shanxi section of the Yellow River Basin. Through this analysis, the study identified the NDVI trends in the Shanxi section of the Yellow River Basin from 2001 to 2020. Additionally, by incorporating meteorological data and information about mining areas, the study investigated the impact of climatic factors on the NDVI variations within the mining regions. The temporal variations in the NDVI in the Shanxi section of the Yellow River Basin exhibit spatial heterogeneity, showing an overall improving trend. These research findings align with conclusions about the gradual increase in vegetation cover in [40] and the Yellow River Basin [41; 42]. The annual growth rate of the NDVI in the Shanxi section of the Yellow River Basin is 1.82% per year. Over the course of 20 years, the NDVI decreased compared to the previous year in only 6 years, while in the remaining years, the NDVI increased compared to the previous year. Moreover, there was a continuous growth trend from 2008  
Figure 8: Partial correlation coefficient between the NDVI and annual cumulative precipitation and distribution of its significance level: (**a**) Partial correlation coefficient between the NDVI and annual cumulative precipitation; (**b**) Distribution of the significance level, divided into 6 grades by significance test using the t statistic: extremely significant positive correlation (r > 0, \(p\leq 0.01\)), significant positive correlation (r > 0, 0.01 \(<p\leq 0.05\)), insignificant positive correlation (r > 0, \(p>0.05\)), insignificant negative correlation (r < 0, \(p>0.05\)), significant negative correlation (r < 0, \(0.01<p\leq 0.05\)), and extremely significant negative correlation (r < 0, \(p\leq 0.01\)). to 2013. Areas with higher vegetation cover in the Shanxi section of the Yellow River Basin are primarily located along the sides of the Lvliang Mountains and Taihang Mountains [43]. This is attributed to ecological comprehensive management projects, such as large-scale afforestation and ecosystem conservation efforts. In contrast, the western highland hilly regions exhibit significant topographical variations, receive less precipitation, and have poorer hydrothermal conditions, resulting in relatively lower vegetation cover. In the areas surrounding mining zones, it can be considered that they are subject to the same climatic influences as the mining areas. The fluctuation in the NDVI within the mining zones is higher than in other regions. To some extent, this suggests that, in accordance with national ecological conservation requirements, improvements in vegetation management within mining areas have led to a relatively higher increase in the NDVI compared to other regions. The NDVI values in the mining areas are lower than the overall NDVI value in the Shanxi section of the Yellow River Basin, which is closely associated with mining activities. Coal-mining activities can lead to land subsidence and surface deformation, which, in turn, affect vegetation growth [44]. Additionally, previous studies have shown that mining activities can impact surface and groundwater, reducing water absorption by vegetation roots and leading to a decrease in vegetation cover [45]. According to government reports, starting from 2006, the national government initiated the first batch of national planning mining zones. These regulations imposed minimum mining scales on various mining areas, with coal mines not allowed to produce less than 1.2 million tons per year. With the implementation of national economic development and ecological environmental governance policies, various mining areas have further reduced their impact on the surrounding ecological environment through policies such as mineral resource integration and the closure and elimination of non-compliant mines [46].