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, Australian Centre for Geomechanics, Perth, pp. 485-492, https://doi.org/10.36487/ACG_repo/908_37
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.
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