Vegetation restoration of slag heap (slope) is of great significance in environmental protection, but it is difficult because of the lack of soil. This study proposes a new technology for vegetation restoration of mine slag pile based on a mixed substrate of mine slag and soil. The ecological mechanism of vegetation in mountainous areas with soil-rock mix substrate was investigated through pot and field experiments, in which physical and chemical analyses of various components as well as the calculation of dosage and other parameters were performed. Soil testing formula, plant selection, pot experiment, and ground planting experiment were selected as the key links. The results showed that, in addition to N, P, K, and organic matter, the content of fine particles was the main factor determining whether the soil-rock mixture could meet the growth and development requirements of plants. The content of fine particles significantly affects the water-supply capacity and water-holding capacity of the soil-rock mixture matrix. The higher the content of fine particles, the better the water-supply capacity and water-holding capacity. The mixture of artificial rocks and fine soil could be stirred evenly when 50-200% fine soil or fine soil + tailings were mixed into the mine waste residue, thus providing good vegetation restoration effects.
Keywords: Grain size composition; Mine abandoned slag; Slag heap; Slag slope; Soil and rock mixture matrix.