The effect of geotechnical creep on the safety and reliability of rehabilitated mine pit-lake slopes

Pit-lakes are gaining increasing attention as a method for large open-pit mine rehabilitation. Large void spaces are filled with water, providing a confining pressure on mine surfaces, decreasing the risk of slope failure, while also reducing the required level of slope maintenance. Although pit lake rehabilitation scenarios present a long-term option for maintaining the stability of mine slopes, soils susceptible to creep under increasing loads due to mine filling presents a risk to long term stability. From a geotechnical point of view, soil creep is generally attributed to slow, downslope movement, where creep movements often decelerate until a critical strain produces a creep failure event. In this research, time-dependent slope stability models of creep-sensitive soils are presented, identifying varying levels of deformation based on mine filling rates and durations. The ability to achieve a final stable landform under a variety of long-term creep conditions is discussed.