The Lihir gold mine, PNG, contains both gold-rich epithermal pyrite and gold-poor porphyry stage pyrite. Epithermal pyrite overgrowths have led to high-gold rims forming on barren cores. Understanding the occurrence and proportion of high-gold pyrite is important in processing considerations.

This new project followed on from AMIRA P1153, and was initiated and completed in 2018. It aimed to develop new LA-ICP-MS protocols for quantification and characterisation of gold-bearing pyrite in processing samples from Newcrest’s Lihir gold mine. A cost-effective method for LA-ICP- MS analysis and data reduction, which allows for fast throughput, was developed. New protocols enable the accurate measurement of gold-bearing rims down to two microns thickness on crushed material. The methodology also allows for reporting on pyrite grain size, proportion of gold-bearing pyrite, thickness of gold-bearing rims and the concentration of gold and arsenic in pyrite.