Author: V. Martin, M. Al-Mamun, A. Small
Conference: 87th Annual Meeting of the International Commission on Large Dams
Date: June 9-14, 2019
Understanding the consequences of a tailings dam breach ultimately leads to designing safer dams and properly preparing for emergencies. Guidelines for dam breach studies are available for water dams, but none of these deal with the hydrodynamic and geotechnical issues related to tailings flows. Since 2013, the Mining Dams Committee of the Canadian Dam Association (CDA) has been working on developing methodologies to improve the way tailings dam breach analyses (TDBA) are conducted. Workshops were organized in 2014 and 2015 to understand the state of practice at the time. In 2016 a CDA Working Group was established to develop guidelines specific to tailings dams. The Working Group led the development of the TDBA Bulletin and feedback was obtained on several drafts including a workshop in 2017.
The CDA Technical Bulletin for TDBA will provide the key steps that should be undertaken. The differences between water retaining and tailings dams will be addressed. The presence of a supernatant pond and the potential of the tailings to liquefy and flow, are the key parameters influencing the runout potential and outflow volume. The physical processes occurring during a TDBA will be discussed with guidance provided on estimating the volume of released tailings during a breach and predicting where the tailings could flow. The TDBA is planned to be issued in 2019.
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