(10)Considerations on Dam Breach Analysis of Tailing Storage Facilities

摘要

The operation of tailings storages facilities (TSF) involves a potential risk for people andinfrastructure located in areas downstream, which may include loss of life, inundation, and damageto buildings such as houses, bridges, farm lands and contamination of water sources. Inconsequence, it is necessary (or mandatory in some countries) to perform a dam breach analysis of aTSF in order to assess the magnitude of the flood wave and volume of tailing released to defineremediation measures. Furthermore, the results of the dam breach analysis can be used to definethe dam classification according to the Canadian Dam Association guidelines. However, it isimportant to mention that most guidelines and codes for dam breach analysis are oriented for waterdams; nevertheless, there are few technical reports or methodologies available for TSF.The objective of this paper is to discuss the technical considerations taken into account when a dambreach analysis of a TSF is performed, based on the practical experience to develop simulations inseveral case studies in Peru. There are two important points to understand dam breach analysis of aTSF: the generation of hydrographs due to the tailings breach and flow routing for identifying theflood timing, depths and velocities through the natural channel and valleys. In order to determinewhich failure mode produces the most critical hydrograph, scenarios such as seismic events,extreme meteorological conditions, poor tailings management, vandalism, among others, wereevaluated according to the work area. Besides, the flow must be modeled as a non-Newtonian fluidusing physical, chemical and rheological properties of tailings. Finally, results of the dam breachanalysis for the case studies will be presented.