Integrated Barrier and Anti-Seepage Technology for Iron Tailings Pond: Application and Environmental Evaluation
This study addresses the deficiencies in material and structural stability and the singular evaluation system in iron tailings pond pollution remediation. Based on an integrated design-construction-evaluation concept, we developed a three-dimensional anti-seepage system incorporating iron tailings sand-bentonite mixtures and a composite liner structure. The system was applied to an actual remediation project in Qichun County, Hubei Province, China, covering an area of 18.72×10^4 m^2 with 43.42×10^4 m^3 of tailings. Theoretical calculations of leachate generation, material testing, and structural optimization were performed. The optimized mixture achieved a permeability coefficient (k) reduction from 10^-4 cm/s to 10^-8 cm/s as bentonite content increased from 0% to 9%, meeting the engineering standard of k≤10^-7 cm/s. A novel 'pre-embedded pipe + expansion bolt' technique enhanced sealing at structural nodes. Post-remediation monitoring showed significant reductions in heavy metal concentrations in surrounding farmland soil (11.14%–72.41% decrease), all below risk screening values. Iron (Fe) and chromium (Cr) interception rates reached 97.17% and 96.76%, respectively. The Nemerow comprehensive pollution index dropped from 2.39 (moderate pollution) to 0.62 (no pollution), and the potential ecological risk index decreased from 288.50 (moderate risk) to 148.73 (slight risk), representing a reduction of 1–3 pollution levels. The project achieved a 2.78% increase in tailings resource utilization and a 4.71% reduction in engineering cost. This integrated technical system provides a viable approach for tailings pollution control and sustainable waste management.