Multilayer Composite Ecological Restoration Mat for Pollution Control and Vegetation Restoration in Abandoned Mine Lands

Mining-generated tailings ponds, waste-rock dumps, and spoil grounds are commonly characterized by poor fertility, heavy-metal contamination, acid drainage, and limited natural revegetation. Here, we present a multilayer composite ecological restoration mat that integrates hydraulic isolation, slope reinforcement, and vegetation restoration within a single system. The mat consists of a geosynthetic clay liner (GCL) that functions as the barrier and water-retention layer, together with a nutrient substrate layer, a plant seed layer, and an anti-erosion layer. Laboratory testing of the evaluated production batch showed a GCL hydraulic conductivity of 1.75108 m/s and a longitudinal tensile strength of 10.28 kN/m, both meeting the corresponding design/acceptance criteria. Hydrated sodium bentonite provides self-healing capability, and the barrier function remained essentially unaffected after root penetration. The nutrient substrate was formulated to provide sustained water and nutrient support under site-specific conditions. Field demonstrations at a copper-mine waste-rock dump in Jiangxi and in the Yushu River Basin in Qinghai showed rapid vegetation establishment under steep-slope and nutrient-poor conditions, together with effective control of acidic, heavy-metal-bearing leachate. These results indicate that the integrated mat provides a practical approach for combining pollution control with vegetation restoration on abandoned mine lands.