This Technical Bulletin, published in 2021, is intended to provide dam safety professionals with guidance for conducting a Tailings Dam Breach Analysis (TDBA). While the Bulletin outlines a step-by-step procedure for detailed dam breach analysis based on the current state of practice, it is the responsibility of dam owners and dam safety professionals to define and agree on the scope and methodology that meets the study objectives and the requirements set by the regulators
Every tailings dam is unique and has site specific conditions and requirements that must be taken into consideration for any technical analysis, including the TDBA. Guidelines for dam breach studies are available for water retaining dams, but none of these guidelines deal with the hydrodynamic, geotechnical and rheological considerations specific to tailings outflows. This Bulletin is intended to provide guidance on the general process and scope for the TDBA, expanding on the Technical Bulletin: Inundation, Consequences and Classification for Dam Safety (CDA 2007) and on the Technical Bulletin: Application of Dam Safety Guidelines to Mining Dams (CDA 2019). Technologies and best practices for TDBA are still evolving, and as such, this Bulletin aims to provide a consistent basis for analysis based on the current state of knowledge.
CDA provides a forum to gather and define consensus on what constitutes good practice for dam safety in Canada. The development of this Bulletin built on the findings from two CDA workshops organized in 2014 and 2015, as summarized in James et al. (2017). The Bulletin development involved an additional five years (2016-2020) of collaboration by members of the Working Group formed by the Mining Dams Committee. Two more workshops were held at annual CDA conferences in 2017 and 2019 for input from CDA members and workshop participants. A technical paper on the draft version of the Bulletin was presented at the 2019 ICOLD Symposium (Martin et al. 2019). Draft versions were reviewed and approved by the Mining Dams Committee members and external reviewers. The final draft was posted on the CDA Member web portal for membership review, and submitted to the CDA Dam Safety Committee and the Regulation of Dams Committee for review and approval before the Bulletin was finalized and accepted by the CDA Board of Directors for publication.
Depending on the objectives and requirements, the TDBA may be simpler than outlined in this Bulletin, using some, but not all the steps discussed herein. The results of the analysis are typically presented on inundation/runout maps and could be used for multiple purposes including dam safety management, hazard and consequence evaluation, emergency preparation and response planning, failure mitigation planning, and mine closure and dam decommissioning planning.
The appendices included in the Bulletin provide supplemental information. Some of these appendices contain information that will require updates as new information becomes available. These appendices include the date when they were last updated. CDA may periodically issue updates to this Bulletin including the appendices or could issue new appendices as required.
You can purchase this bulletin at the CDA Store, under the title EN - Tailings Dam Breach Analysis Technical Bulletin 2021. It is currently only available in PDF format.