Best practice sampling methods, assay techniques, and quality control with reference to the platinum group elements (PGEs)
K Lomberg
In this paper the process of sampling and assaying as it relates in
particular to the platinum group elements (PGEs) is presented. A
discussion of the geology of PGE deposits is included to provide an
understanding of the mineralization that is considered necessary
prior to sampling, as this has a direct bearing on the mineral resource
estimate and also the selection of an appropriate mining cut. The
discussion includes the selection of the sampling technique (drilling
or face sampling), the size of the sample relating to the requirements
of the laboratory, the potential mining cut, as well as a reference to
sampling theory. The selection of an assay technique that is
appropriate and will yield the optimal result based on sample
turnaround, precision, accuracy, and cost is then considered.
Examples are drawn from work undertaken on the Bushveld Complex
(Merensky Reef, UG2 Chromitite Layer, Platreef) and Great Dyke
(Main Sulphide Zone). A discussion of the appropriate QA/QC
programme includes the chain of custody, CRM selection and the
QA/QC process.
Keywords: sampling, assaying, QA/QC, platinum group elements.