Considerations for Preparing Design Criteria for Dewatered Tailings Facilities

Author(s): 
Pepe Moreno, Samuel Kendall
Date: 
Wednesday, July 10, 2019
First presented: 
Tailings 2019
Type: 
Published paper
Category: 
Mine Waste
 
 
Dewatered tailings facilities (thickened, paste, filtered) are generally considered safer alternatives to conventional tailings disposal, primarily due to the lower amounts of water stored as a pond or interstitially within the tailings mass. While it is acknowledged that a risk-based approach to TSF design should always be followed, the pressure to deliver projects quickly and often within limited budgets creates a tendency to rely on standards-based design criteria which may not always be directly applicable to dewatered tailings facilities.

Key design criteria commonly adopted from conventional TSF design are driven by the Population at Risk (PAR) and Dam Failure Consequence, slope stability Factors of Safety (FOS), Stormwater storage and Earthquake Loading. For dewatered tailings facilities it is important for stakeholders to recognise that prescriptive design elements, typically adopted from conventional TSFs, may not represent the most critical sources of risk, and therefore selection of design criteria should be case-specific.

There is arguably a void in international guidelines with respect to incorporating a design flowchart to streamline the design of dewatered tailings facilities. This paper discusses current practice for evaluating key TSF design criteria, taking as a base leading guidelines such as MAC (2019), ANCOLD (2012) and CDA (2007, 2014), and relates this to the context of dewatered tailings facilities. It identifies important elements to consider, issues likely to be encountered and areas of improvement, and provides a basis for continuing research and discussion.

 

Feature Author

Pepe Moreno

Juan Moreno has more than 25 years of diversified professional experience in projects mainly associated with geotechnical/ geoenvironmental engineering for the mining and civil industries throughout the world. Pepe is typically involved as team leader conducting conceptual to detailed engineering for mine waste facilities, including design of tailings disposal systems using a wide range of dewatering levels, waste rock dumps, and effluents containment. His experience covers from site investigation to closure design including advanced modelling for dam break analyses and water balance and geotechnical design for tailings facilities, heap leach pads, ponds and waste rock dumps. Pepe provides expert review for tailings and waste management for due diligence and peer review projects for banks and potential investors.

Principal Consultant (Mine Waste)
Civil Eng, MIEAust, CPEng, RPEQ
SRK Perth
Sam Kendall

Sam Kendall is a consultant with more than five years’ experience specialising in tailings and mine waste management. Sam has experience with diverse projects in Australia and across the globe, encompassing a variety of commodities, climates and tailings disposal methods, including thickened tailings and dry stacking. He has been involved in numerous desktop designs and site-based duties, including geotechnical investigation, greenfield site selection, design, numerical modelling, cost estimation, risk assessment, auditing and closure. His recent work includes pre-feasibility and feasibility design of a filtered tailings stack for a lithium project Western Australia.

 

Consultant (Mine Waste)
BEng Hons (Civil), MIEAust
SRK Perth
SRK Africa