Static Liquefaction Analysis of the Limonar Tailings Dam in Peru

Abstract

Tailings disposal has been a major concern for mining companies around the world with the overall goal to protect the environment and population from hazards associated with tailings storage. Large amounts of waste are produced daily in ore processing plants and depending on the industrial production waste the storage structure (tailings dam) needs to be redeveloped. A typical method for expanding the reservoir capacity is by raising the height of the dam body. The upstream method begins with the construction of a starting dike; after this step, tailings are deposited upstream, forming a beach that thickens over time, gradually increasing the waste strength and serving as a foundation for future dikes. This procedure goes on until the planned design size is reached. It is a simple and low cost method but its main drawback is that an excessive construction speed can induce static liquefaction, the main cause of the collapse of several tailings dams. This paper investigates the liquefaction potential of a copper tailings dam situated in Peru. Results from an empirical method, based on Standard Penetration Test data, are compared with those obtained with a more complex analysis carried out with a finite element program using an elastoplastic constitutive model. It has been concluded that both methodologies were suitable in order to predict the possible occurrence of static liquefaction.