Ecological environment quality changes of abandoned mining area based on remote sensing: a case study of Maoming oil shale mining area

The exploitation of Maoming oil shale has significantly contributed to the local economic development. However, the mining activities have resulted in a series of ecological and environmental issues. In 2013, the comprehensive ecological restoration project for the Maoming open-pit mine was officially initiated. To monitor the ecological rehabilitation process of abandoned open pit mines, this study focuses on the Maoming oil shale mining area. The temporal and spatial evolution characteristics of the ecological environment in the Maoming oil shale mining area after closure were analyzed using Landsat remote sensing images from 1993 to 2021, taking into consideration factors such as the water area of the pit, fractional vegetation cover(FVC), and remote sensing ecological index (RSEI). Geographical detector analysis was employed to investigate the influencing factors of ecological environment quality in the study area. The results revealed that: (1)after the mine was abandoned, the water area within the mine gradually expanded and stabilizing at 4.6 km² after 2017.(2)Within the 1 km buffer zone of the mine, the value of FVC exhibited minor fluctuations from 1993 to 2013, and showed a significant increase trend from 2014 to 2017, then the growth rate slowed down after 2017. The average of FVC of the north dump reached a value of 0.809 in 2008, and subsequently remained relatively stable(. 3)Within the 1 km buffer zone of the mine, there was a noticeable increase in RSEI average values during the mine restoration period, although some areas still experienced slight declines, indicating that implementation of the project may have had certain impacts on the ecological environment during this phase. The average of RSEI of the north dump demonstrated an increasing trend and tended towards stability after 2007. (4)Land use and night light significantly influence spatial distribution patterns of ecological environment quality in this region. This study serves as a valuable reference for evaluating ecological environment quality in mining areas.