Centrifuge Modeling of Mine Tailings and Waste Rock Co-Disposal, Consolidation, and Dynamic Loading

Tailings from a planned copper-gold mining project located at the earthquake-prone Andean region of South America were obtained from the metallurgical pilot plant in order to perform centrifuge tests at the center for earthquake engineering simulation (RPI). Consolidation and shaking table tests were conducted to evaluate the properties and liquefaction potential of mildly sloped consolidated mine tailings. A gentle slope at the surface of a tailings impoundment can significantly add to the stored volume. Due to long consolidation time, large settlement and clear signs of liquefaction after a few cycles of dynamic loading, the need for improvement arose. One of the alternative management methods that can improve physical stability and geochemical properties is co-disposal of mine tailings and waste rock. In this study, co-mixing of the materials at a specified ratio of dry mass (waste rock to tailings) prior to disposal was examined. The behavior was compared to that of tailings with respect to consolidation rate, settlement accumulation, slope stability and response to dynamic loading. In the field, the tailings are thickened and hydraulically deposited into the containment structure in layers. In the centrifuge, tailings were prepared in layers and consolidated, thus allowing instrumentation of each layer before consolidation of the complete impoundment.