Authors: Brett, DM


Cite As:
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,

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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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