Optimal allocation of technical reclamation and ecological restoration for a cost-effective solution in Pingshuo Opencast Coal Mine area of China.

Limiting adverse consequences of mining activities requires ecosystem restoration efforts, whose arrangement around mining areas is poorly designed. It is unclear, however, where best to locate ecological projects to enhance ecosystem services cost-effectively. To answer this question, we conducted an optimized ecological restoration project planning by the Resource Investment Optimization System (RIOS) model to identify the restoration priority areas in the Pingshuo Opencast Coal Mine region in Shanxi Province. This region features notable mining activity, agricultural land use, and urban development. We found that the land use changes were primarily influenced by human activities such as mining and urbanization, as well as ecological interventions from 1986 to 2022, during which the area of industrial and construction land continuously expanded. The RIOS model was configured using input data such as land use, digital elevation models (DEM), and biophysical coefficients. Ecological restoration objectives were selected, including Erosion Control for Drinking Water Quality, Erosion Control for Reservoir Maintenance, Nutrient Retention, and Baseflow. Investment optimization scenario simulations revealed that over 90% of ecological projects in the Pingshuo Opencast Coal Mine are distributed in the low-slope areas (0°-15°). Four types of technical reclamation and ecological restoration projects, i.e., agroforestry, grass strips, riparian management, and terracing, exhibit strong preferences for specific locations. Riparian management and agroforestry tend to be distributed on soil dumps; terracing and grass strips tend to be distributed in the upstream agricultural areas of rivers and junctions of watershed gullies and slopes. The model prioritized areas based on ecological restoration goals and stakeholder interests, optimizing locations that would maximize ecological benefits while addressing the objectives. Moreover, depending on the different goals of ecological restoration in the mining area, investment plans that maximize benefits for stakeholders should range between 3 and 6 million dollars. While the restoration strategies in this study were designed for the Pingshuo region, they hold potential for other mining areas with similar biophysical conditions, surrounding ecosystems, and mining scales. The RIOS model adjusts its recommendations based on specific input data, making it adaptable and broadly applicable to other mining area. The results of this study positively contribute to alleviating the conflict between ecosystem protection and socioeconomic development in mining areas, scientifically regulating ecological restoration activities, and enhancing ecosystem services. Our results provide evidence that ecological restoration interventions contribute measurably to restore the degraded ecosystems in the mining areas.