## 4 Discussion
### Buffer Analysis of a Typical Mine Sites
Specifically, coal mining activities can lead to problems such as land hardening, reduced vegetation cover, and increased coal dust pollution, thus negatively affecting an ecosystem. The spatial distribution and temporal changes in these impacts can be quantified through buffer zone analysis. For example, in the Sihe Mine Area, the ecological quality of the central area declined significantly with mining activities, while in the area away from the mine area, the ecological quality improved as a result of the government-implemented policy of returning farmland to forest. In addition, there were differences in the ecological impacts of different mine areas. For example, the ecological impact of the Fenghuangshan mine was relatively small due to its low production, but ecological restoration measures significantly improved the ecological quality of the area as the mine ceased production and was closed. This suggests that the scale of production and management measures at the mines played an important role in their ecological impact. Through these analyses, certain beneficial steps were determined as the following: (1) When selecting a new mine area, its potential impact on the surrounding ecological environment should be fully considered, and priority should be given to selecting areas of lower ecological sensitivity. (2) In the process of the planning and construction of mine areas, measures should be taken to reduce land hardening and vegetation destruction and to minimize negative impacts on the ecological environment. (3) After the suspension or closure of mine areas, ecological restoration work, such as planting trees and restoring wetlands, should be carried out in a timely manner in order to improve the quality of the ecological environment. (4) Long-term ecological real-time monitoring and restoration efforts play a crucial role in protecting the ecology of mine areas. The results of this study emphasized the efficiency and practical value of the RCEI in assessing the quality of an ecological environment. The construction of the RCEI was based on selected ecological indicators that not only accurately reflected the physical characteristics of the surfaces in resource-based cities, but could also be efficiently computed by remote sensing technology. Therefore, the RCEI provides a convenient and rapid means for evaluating the ecological environmental status of resource cities. In addition, the RCEI supports the visualization and analysis of spatial and temporal dynamics of ecological environmental quality. Compared with traditional EI indicators, the RCEI is easier to popularize and apply. It is especially worth mentioning that the RCEI, as a comprehensive evaluation tool based on the PSR model, is more comprehensive than most existing indicators in considering the impacts of production pressure in mine areas and urban construction and expansion. Therefore, the RCEI not only guides the standardization of coal mining activities and urban construction, but also reduces irrational development in the development of resource-based cities, which provides important decision-making support for improving and upgrading the quality of the ecological environment.