Adequacy of sampling for AMD
To assess the risk of acid and metalliferous mine drainage (AMD), most new mining projects require an initial assessment of the locations and volumes of potentially acid forming (PAF) waste that is likely to be moved and dumped in waste stockpiles. This requires sampling of the waste rock zones and submitting the samples for a series of tests. Key to the outcome of the waste characterisation process is obtaining sufficient samples that are representative of the various rock types, both in number and spatial distribution.
Various regulatory bodies throughout Australia and the rest of the world are currently struggling with how to define minimum amounts of sampling to achieve realistic estimates without imposing excessive costs and time constraints on a project.