Study on the assessment of mine ecological restoration of the Sanjiang metallogenic belt in Yunnan province, China

This paper assesses the mining ecological restoration of the Sanjiang metallogenic belt in Yunnan province, using remote sensing monitoring results and regional natural geographic data. The evaluate system includes four mine exploitation indexes (land occupation type, mining method, mineral species, and pollution type) and six physical geography indexes (altitude, slope, aspect, land cover type, rainfall, and illumination time). Using the Analytic Hierarchy Process (AHP) method, the study area has been divided into severely affected zone, heavily affected zone, moderately affected zone, and weakly affected zone, whose areas are 80.68 km², 3356.80 km², 6640.84 km², and 174569.36 km², respectively, accounting for 0.4%, 1.8%, 3.5%, and 94.1%, respectively. The assessment results indicate that mining ecological restoration of the severely affected and heavily affected zones should mainly focus on the extensive damage to vegetation and land resources caused by large-scale open-pit mining, as well as the acidification and heavy metal enrichment of water and soil caused by long-term accumulation of heavily polluted solid waste. The mining ecological problems of the moderately affected zone are mainly the occupation of land resources caused by transfer sites and solid waste, as well as the damage to landscape caused by mining. In the weakly affected zone, the mining activities are of small scale and distribute sporadically, which have relatively minor effects on the ecological environment of mines.