An assessment of portable X-ray fluorescence spectroscopy in mineral exploration, Kurnalpi Terrane, Eastern Goldfields Superterrane, Western Australia

Abstract

Portable X-ray fluorescence (pXRF) technology is fast becoming an important part of the geochemical toolkit for exploration geology. However, the relatively new development of this technology means that the awareness of the issues and pitfalls in pXRF use is lacking somewhat in both industry and academia. For some, pXRF analyses are becoming a panacea and involve an instrument that can be used with little consideration of the data quality and calibration issues that might be associated with the data. This study aims to highlight key considerations in using pXRF during the early phases of exploration within a geologically and geochemically poorly constrained gold deposit. In this scenario, pre-existing manufactured standards may not be adequate to ensure the accuracy of the pXRF analyses. Instead, the use of laboratory-based whole rock analyses of representative samples from the project area act as orientation samples designed to establish reference compositions and used to derive correction factors to apply to pXRF data. These data also highlight the issues in the common industry practice of taking pXRF measurements of pulverised samples through paper packets, an approach that introduces bias towards underestimating the concentrations of many elements of interest and must be mitigated against in order to ensure pXRF data are both accurate and precise.