Reconstruction of spatiotemporal processes and identification of active status for disturbance and recovery in...

While open-pit coal mining brings economic benefits, it also poses severe threats to the ecological environment. Assessing the active status of open-pit coal mines and analyzing their mining conditions and change trends are crucial for achieving sustainable development balancing extraction and environmental protection. To address this, this study combined Landsat imagery, the Open Coal Frequency Index (OCFI), and the LandTrendr change detection algorithm to reconstruct the mining disturbance and reclamation recovery processes of all open-pit coal mining areas across China from 2000 to 2023 on spatiotemporal scales. Furthermore, by constructing a method for discriminating the active status of open-pit coal mines based on a disturbance coefficient, dynamic monitoring of the active status of open-pit coal mines from 2000 to 2023 was conducted. Our results indicate that: (1) A total of 11,261 open-pit coal mine patches (6251.09 km²) were identified across China. The spatial distribution pattern of open-pit coal mine patches shows more in the west than the east, and more in the north than the south. (2) Overall, the average reclamation recovery rate for open-pit coal mines was 28.51%. However, mining disturbance and reclamation recovery are temporally asynchronous. Large-scale reclamation recovery occurred after 2012, and after 2020, the annual newly reclaimed area exceeded the newly disturbed area. (3) From 2000 to 2023, the number of active coal mines in China gradually decreased, but both coal production and mining area increased, reflecting the development trend of large-scale mining in China's open-pit coal mines. These results can provide scientific references and methodological support for achieving sustainable development in mining and environmental protection.