Laser-ablation inductively-coupled-plasma mass spectrometry and electron probe microanalyses of pyrite and pyrrhotite in tailings and ores from volcanogenic massive sulfide and sedimentary-exhalative deposits

Mine waste, including mill tailings, could host substantial critical mineral resources. Developing an understanding of the mineral hosts and occurrence of critical minerals in mine waste is essential to evaluating their resource potential. Volcanogenic massive sulfide (VMS) and sedimentary-exhalative (SEDEX) deposits are important global sources of copper, zinc, lead, gold, and silver, and may contain economic to sub-economic concentrations of critical mineral commodities including cobalt, nickel, arsenic, antimony, and bismuth. Waste material from these deposit types typically contains significant concentrations of the gangue sulfide minerals pyrite and pyrrhotite, which are known to host trace to weight-percent concentrations of some critical minerals such as Co, Ni, or As. Pyrite and pyrrhotite also represent a potential environmental liability when associated with mine waste because their weathering generates acid-mine drainage. Identifying additional value in these minerals may encourage mine waste reprocessing, helping to mitigate their environmental effects. Comparing the geochemistry of pyrite and pyrrhotite in tailings and ore samples allows the composition of the ore material to be correlated to the composition and critical mineral endowment of existing or potential waste from that deposit. This data release provides micro-analytical geochemical information on pyrite and pyrrhotite in tailings and ores from volcanogenic massive sulfide and sedimentary-exhalative zinc-lead deposits in order to determine the mineralogical hosts (that is, inclusions or in solid solution within the crystal lattice) and range in concentrations of critical minerals.

Pyrite and pyrrhotite grains in tailings and ore samples from deposits in the United States (Ducktown VMS, Elizabeth VMS, Bald Mountain VMS, Callahan VMS, Cofer VMS, Iron Mountain VMS, Red Dog SEDEX), Finland (Kotalahti VMS, Luikonlahti VMS, Hammaslahti VMS), Canada (Corbet VMS, Kidd Creek VMS, Anvil-Faro SEDEX, Sullivan SEDEX), and Australia (McArthur River SEDEX) were analyzed for their trace element chemistry using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Additionally, pyrites in samples from the epithermal Katherine mine in AZ, USA were analyzed by LA-ICP-MS. These data represent spot chemical analyses in parts per million (ppm) collected using an Applied Spectra Resolution S155 laser-ablation system and an Agilent 8900 mass spectrometer at the USGS L-TRACE laboratory in Denver, CO. Raw data were analyzed using the software program LADR (https://norsci.com/?p=ladr). One .csv file is provided (PyPo-VMS-SEDEX_2024_LAICPMS.csv) that detail the measurements collected, analytical error, and measurement conditions.

Samples from the Elizabeth (USA), Cofer (USA), and Hammaslahti (FIN) VMS deposits, and the Anvil-Faro SEDEX deposit (CAN) were analyzed using electron microprobe analyses. These data represent chemical analyses in weight percent (wt%) collected using a JEOL 8530F Plus SuperProbe electron probe microanalyzer (EPMA) in the USGS Denver Microbeam Laboratory in Denver, CO on pyrite and pyrrhotite grains in tailings. A text file of results is provided in comma-separated by value (csv) format. The file has the name “PyPo-VMS-SEDEX_2023_EPMA.csv”.