ABSTRACT
The mining industry usually resorts to dams as tailings storage facilities, and these structures represent a significant risk to the environment and surrounding communities if inadequate solutions are implemented. Several failures of such structures have happened before resulting in disastrous consequences, which has made society aware of the need for proper governance of tailings dams based on risk assessment and safety evaluations. After the most recent tailings dam failures, the concern associated with upstream tailings dams intensified, leading, in some cases, to the need for decommissioning design of these structures in order to prevent further failures. Within the process of improving tailings management systems, risk analysis methodologies have become an important tool. This paper resorts to a set of upstream tailings dam decommissioning designs to identify key aspects related to risk management of such structures before, during and after decommissioning. The application of the Failure Modes Effects and Criticality Analysis (FMECA) allowed to identify the main risks associated with the decommissioning of the dams and to define preventive and mitigation actions as well as controls to be implemented in order to minimize the risk, consistent with the principles of Global Industry Standard on Tailings Management.
