Green, R, Linklater, C, Lee, S, Terrusi, L & Glasson, K 2019, 'Rio Tinto’s framework for evaluating risks from low sulfur waste rock', in AB Fourie & M Tibbett (eds), Proceedings of the 13th International Conference on Mine Closure
, Australian Centre for Geomechanics, Perth, pp. 855-870, https://doi.org/10.36487/ACG_rep/1915_68_Green
There is an increasing need in mine closure studies for a toolbox of procedures designed specifically for application to low sulfur waste types – to help build confidence in the generally accepted premise that these wastes have a low risk profile. Historically, mine waste characterisation efforts have focused on materials with elevated sulfur. This is warranted due to the greater risk associated with acid and metalliferous drainage from potentially acid forming wastes. Test procedures for materials with elevated sulfur are well established. Regarding low sulfur and non-acid forming materials, the toolbox of geochemical characterisation procedures can vary significantly depending on personal preference and jurisdictions.
The framework for geochemical characterisation of low sulfur waste materials at Rio Tinto’s Pilbara Mines will be presented. This framework involves phased testing, starting initially with a wide range of samples from different locations and depths. Progressively more detailed tests are undertaken, depending on the waste storage conditions and unresolved issues or uncertainty. Risk assessments are undertaken in conjunction with geochemical testing to evaluate risks posed by waste material properties and tonnages. There is no ‘one size fits all’ test method for low sulfur waste material. This Rio Tinto framework provides flexibility by using a combination of test methods to understand and, if necessary, appropriately manage any risks identified.
Keywords: neutral mine drainage, geochemistry, mineral waste management
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