Study on Tailings Covering System Constructed by Geological Polymerization of Mine Waste. Part 2: Simulation of Oxidation Inhibition of Overburden on Acid-producing Tailings.

Acid mine drainage (AMD) is a well-recognized environmental issue associated with mining production worldwide. The second part of our study aims to assess the protective effect of using a polymer hard layer (PHL) by conducting sulphur-enriched tailing-based column experiments. An oxygen (O2) barrier was simulated using a designed column device filled with different types of tailings. All experimental columns underwent six drying-wetting cycles, and the chemical properties of the tailings and leachate were detected after every cycle. The permeability coefficient of the PHL was only 1.16 × 10- 5 cm/s. Over the entire experimental period, none of the leachates collected from column 4 using the PHL as an O2 barrier. Moreover, the level of redox potential and pH and the contents of heavy metals such as Cu and Zn were stable in PHL covering system. These results show that a PHL is the optimal covering system.