Pioneer Resources Sinclair Caesium Discovery: Matrix Matched Calibration aids in rare find of caesium.

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Pioneer Resources (PIO) officially opened Australia’s first caesium mine, Sinclair on 19th September 2018. Located 40 km north of Norseman, Western Australia, Sinclair represents an significant caesium discovery that has taken two years from initial drilling to bring into production.

Originally targeting lithium on the Pioneer Dome, using Portable XRF Services matrix matched calibration in conjunction with the Bruker Titan handheld XRF, Pioneer Resources targeted LCT Pegmatites.  During drilling of the discovery hole, PDRC015, elevated pXRF caesium values were observed, reaching a maximum of ~6% Cs. Although elevated the significance was not fully appreciated until laboratory assays were received.   The underestimation of Cs (Figure 1) was due to low Cs values in available CRM’s and reference materials and as elevated caesium is rare, it is not included on any factory calibrations. Once the high percentage samples were added to the calibration it was possible to recalculate all the data up until that point by reprocessing the PDZ files of the pXRF analyses that had been done (Figure 2). By using the initial matrix matched calibration that was developed for Pioneer Resources, Cs along with other LCT Pegmatite elements, including but not restricted to  Ga, Nb, Rb, Sn, Ta, and Tl on Bruker Titan handheld XRF enabled an early realisation of the significance of the Sinclair discovery…..the rest as they say is history.

Figure 1: Original calibration Cs up to

Figure 2: Following addition of high Cs up to