Brett, DM 2009, 'Water covers for tailings and waste rock — designing for perpetuity', in AB Fourie & M Tibbett (eds), Mine Closure 2009: Proceedings of the Fourth International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 485-492, https://doi.org/10.36487/ACG_repo/908_37
(https://papers.acg.uwa.edu.au/p/908_37_Brett/)
Abstract: Water covers are recognised as a preferred method of controlling oxidation of sulphides in tailings and 
waste rock, in climates where the availability of water is adequate to maintain continuous saturation. 
However, there is a resistance to this method for long-term, low maintenance closure of these storage 
facilities due to the perceived risks associated with water storage dams. Dams are closely regulated by 
government in most jurisdictions and require management systems appropriate to the hazard rating of the 
structure. This is determined in Australia using guidelines issued by the Australian National Committee on 
Large Dams (ANCOLD) and others, relating to the consequences of failure. Most mine storages would fit 
into the ANCOLD high hazard rating due to the environmental impact of their failure. The hazard rating 
imposes recommendations for design parameters, construction details and ongoing operational 
management. However, these recommendations have generally been developed for operating water storage 
dams and require a level of management that becomes unrealistic for a closed mine storage. The solution is 
to develop design and construction practices for mine waste storages that reduce the risk of failure to 
acceptably low levels that allow reduction in the scope of long-term management.  
This paper describes how risk assessment methods can be used to develop the design of mine waste storages 
that can support water covers for long-term performance.