Applied research on the numerical simulation of Cu and Cd transport laws in a metal mining area

China is paying increasing attention to the ecological environment, and heavy metal pollutants produced during mining and smelting in metal mines have caused serious environmental problems to the soil in mining areas. Heavy metal pollution by Cd and Cu in the soil of a metal mining area in Leiyang City, Hunan Province, China, is used here as an example. The total content of heavy metals and the contents of various forms were determined. High Cd and Cu contents were found, and the main forms of the two heavy metals were in the residual state. Then, using the COMSOL software, the migration and evolution of Cu and Cd in the soil were predicted by real simulations. On this basis, a soil management plan was explored. The migration model shows that within 30 days, the pollutant concentration gradually decreases with increasing depth, and most of the heavy metals are concentrated in the surface layer of the soil; after migration, Cd and Cu have different concentrations at various depth levels in the soil. Among them, the soil concentration is the highest in the range of 0 cm–10 cm depth. As the depth reaches 30 cm, the concentration gradually stabilizes. The conclusions of the study provide a scientific basis for the rational use and ecological restoration of mining areas and the prevention and control of soil pollution in mining areas.