RESEARCH & DEVELOPMENT: FINDING GOLD WITH X-RAY FLUORESCENCE

X-ray fluorescence analytical techniques have a long history in rock characterization. By carefully considering the concerns of using XRF on heterogeneous materials, Veracio pioneers XRF use onsite at mining locations to generate real-time orebody knowledge. Funded by the NSF INTERN opportunity for graduate students, I assisted in the research and development of their new XRF system aimed at accurately quantifying heavy elements that are challenging to accurately measure by current XRF systems, such as gold (Au) and rare earth elements. The goal of this project was to conduct a repeatability study to ensure the output of the new instrument is consistent and easily replicated. Specifically, we used the OREAS certified reference material 299 to repeatedly collect spectrum and measure the Au Kα-peak counts for two different analytical procedures. The results revealed that while the placement of a sample had no effect on the resulting counts, pausing the x-ray beam between analyses does affect counts as well as the board temperature recorded by the detector. During both tests, each sample was analyzed 12 times to collect statistical data on the variation between analyses. The first test was conducted by removing and replacing a sample in between each analysis to simulate placement of a new sample, while the second test was conducted by not moving samples or pausing the x-ray beam between analyses. When the beam is paused, and samples are moved the counts are lower and temperature higher but is overall more consistent than when the beam is not paused and instead gradually warms up over time. The counts for all analyses fall within the 2σ, indicating that variation is generally low. This study indicates that the differences in the recorded temperature trends may require further investigation as it does appear to affect the resulting counts, for Au in particular. By highlighting the difference of results between two styles of analytical procedure it contributes to the improvement of this new XRF technology. This internship opportunity not only enabled me to develop my knowledge of physics of XRF instrumentation and learn about some of the newest developments in mineral exploration, but to gain experience beyond the academic community and collaborate with industry.