Measurements of gold in ores by laser-induced breakdown spectroscopy (LIBS)

Numerous rock samples are taken from gold mines on a daily basis and sent to laboratories for gold determination by fire assay. A 48-hour delay in the delivery of results may force mining operators into either making operational decisions prior to knowing the results, or delaying work progress. In both cases, the decisions made can lead to significant losses for the mine. Real-time measurement of gold content in ores may provide a solution to this problem. Such an approach could be achieved by the emerging technology known as Laser Induced Breakdown Spectroscopy (LIBS), which provides in-situ real-time quantitative gold analysis. In order to achieve this goal, the purpose of the project was to calibrate and validate the current technique. The following steps were taken: petrographic and mineralogical study for the determination of macrofacies and the gold grain distribution; x-ray fluorescence (XRF) quantitative analysis for the classification of samples; gold measurements in rock cores and grab samples by LIBS and validation with chemical fire assay.