The number and distribution of waste rock samples geochemically characterised before and during mine operation impacts the ability to accurately represent the waste characteristics and to predict the potential for acid and metalliferous drainage (AMD). Numerous regulatory and industry bodies recommend the number of samples that are to be characterised.
Commonly, the practitioner is advised to take account of the complexity of the geology and the scale of the mine. However, in many instances, the scientific and statistical basis for the recommended numbers is either not provided or is not clear. Consequently, there is ambiguity as to how the recommendations should be applied to a particular mine at a particular stage of development.
This paper demonstrates how conclusions regarding the potential for AMD production at a mine can depend on the number of samples characterised and the specific samples selected for characterisation. Data from three mines are used to illustrate the impact of various sample numbers on preliminary conclusions related to the potential for AMD.
