Significant 1:1,000 0.3m Low/ Significant 1:1,000 1:10 1:100,000 1:10 High C Probable Maximum 0 Flood (PMF) 1:100,000 1:10 High B PMF 0 High A/Extreme PMF 0 Designers should be aware that these are minimum requirements, and should consider the costs and potential benefits in terms of reducing the overall risk by adopting more stringent criteria. Table 3 - Tailings storage facilities ENVIRONMENTAL SPILL FREEBOARD (ANCOLD 2012a) Contingency Storage Allowance Design Storm Maximum Storage ANCOLD Wave Operating Capacity Environmental Freeboard Level Spill Allowance (m) Additional (AEP of Consequence (Wave Height + Freeboard (AEP of 72 hour Category Run up) Design rainfall (m) Wet Year) event) (AEP of Design Wind) Low Nil 1:5 1:10 Nil Low Nil 1:10 1:100 Nil Low 1:10 / Nil 1:5 Nil 1:100 1:10 1:100 1:10 0.3 Significant 1:10 0.5 High C 1:100 1:100 High B, A & 1:100 to 1:1000/ 0.5 Extreme 1:1000 1:10,000
Significant 1:1,000 0.3m Low/ Significant 1:1,000 1:10 High C 1:100,000 1:10 Probable Maximum Flood (PMF) 0 High B 1:100,000 1:10 PMF 0 High A/Extreme PMF 0 Designers should be aware that these are minimum requirements, and should consider the costs and potential benefits in terms of reducing the overall risk by adopting more stringent criteria. Table 3 - Tailings storage facilities ENVIRONMENTAL SPILL FREEBOARD (ANCOLD 2012a) ANCOLD Environmental Spill Consequence Category Design Maximum Operating Level (AEP of Design Wet Year) Storm Storage Capacity (AEP of 72 hour rainfall event) Contingency Storage Allowance Wave Freeboard Allowance (m) (Wave Height + Run up) (AEP of Design Wind) Additional Freeboard (m) Low 1:5 1:10 Nil Nil Low 1:10 1:100 Nil Nil Low 1:5 1:10 / 1:100 Nil Nil Significant 1:10 1:100 1:10 0.3 High C 1:100 1:100 1:10 0.5 High B, A & Extreme 1:100 to 1:1000 1:1000/ 1:10,000 0.5
Guidelines-for-Design-and-Management-of-Tailings-Storage-Facilities_April-2017-Accessible-Version.docx