Field analysis of low ppb gold using pXRF and new detectORE technology

Abstract

The ability to easily analyse for Au in the field at meaningfully-low levels for mineral exploration has not been achievable until now. Portable X-Ray Fluorescence (pXRF) has been a game changer for explorers when it was first introduced about a decade ago. However, whereas pXRF can analyse for metals such as Cu, Zn, As and Fe at concentration levels relevant to mineral exploration, it can only effectively analyse for Au above 10 ppm and only then when interfering elements are in low concentrations. Here, new patent-pending detectORE technology is presented that can detect Au using a pXRF at five orders of magnitude lower. The method has been tested against certified reference materials and whilst not a “total” Au method like fire assay or neutron activation analysis, it provides the mineral explorer with crucial analytical results in the field; geochemical exploration relies on comparative rather than total Au results. Having data available during the execution of a soil sampling or drilling program allows the geologist to make critical decisions on where to collect next “on-the-fly”. For example, changing the drilling plan to define the extent of the mineralisation in a first pass campaign. Currently, mineral explorers may have to wait weeks or months before the results of the Au analysis are returned from the analytical laboratory, and by this time drilling is over, possibly for another year. Medium to small exploration companies can ill afford to wait that long where reporting of positive results is important to their success.