Application of LA-ICP-MS trace-element analysis for precious metal deportment: a case study of the Kevitsa mine, Finland

The Kevitsa mine, located in northern Finland, contains disseminated Ni–Cu–Fe sulphides and platinum-group minerals. Earlier studies had reported trace concentrations of platinum-group elements in several minerals using the electron microprobe. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), which has much lower limits of detection, was used in the present study to target potential carrier minerals (sulphide, sulpharsenide, and arsenide) as part of a process mineralogy study of the ore, with the data used to determine the deportment of the precious metals. Trace precious-metal data were obtained on pentlandite, pyrite, gersdorffite, maucherite, and nickeline for Rh, Pd, Os, Ir, Pt, and Au. A unique feature of the data was the new discovery that nickeline is a significant carrier of Au (up to 74.1 ppm), in addition to Rh, Pd, Os, Ir, and Pt. The unexpected concentration of gold in nickeline demonstrates the versatility of LA-ICP-MS analysis when using an appropriate calibration standard and established protocols.