The effects of cement on some physical and chemical behavior for surface paste disposal method

Abstract

Environmental impacts resulting from conventional tailings disposal such as tailings dam accidents are a common problem for base metal mines around the world. In this context, laboratory-scale studies have been carried out on the Surface Paste Disposal (SPD) method, which is one of the alternative surface storage methods. In this study, three different SPD designs were tested; and volumetric water content, oxygen consumption, and matric suction sensors in first, fifth and 10th paste layers plus pH- electric conductivity (EC) values were all measured. Specifically, it was determined that the amount of oxygen in the environment required for the oxidation of sulfur minerals is reduced in the cemented layers in Design 3. In addition, the cement additive keeps the pH values of the seepage in an alkaline environment (over 7) so that it minimizes the risks of Acid Mine Drainage (AMD) and heavy metals mobilization at low pH values. Also, the EC values started a downward trend and ion dissolution decreased in designs with cemented layers. As a result, it was understood from the sensor measurements that the cemented layers act like a barrier.