Cobalt enrichment in some ores of the Bergslagen province, south central Sweden

ABSTRACT

The presence of cobalt (Co) in sulphide deposits or sulphide-bearing iron oxide deposits in and around the Palaeoproterozoic Bergslagen ore province, south central Sweden, led to focused mining and extraction of this metal, particularly during the nineteenth century. Today, Co is considered a critical metal in the EU and among the more sought-after raw materials, not least due to its use in batteries for the rapidly increasing production of electric vehicles. Here we report new observations and data on Co concentrations in variably mineralised and not necessarily statistically representative samples from a suite of mainly skarn-hosted, at least locally, sulphide-dominated mineralisations from Bergslagen. While several localities that exhibit substantial Co concentrations represent deposits previously known to carry this metal (generally in a field/district or specifically in a mine), the majority are from mines or prospects in which the presence of Co have been hitherto unknown. Several of them share the enrichment of, e.g., Co and Cu, but the overall picture is one of more complex interrelations between the variable metal endowments in the known occurrences of Co in this province. While representing a modest dataset, our new observations complement previously available information on the occurrence of Co in Bergslagen and highlights both the need for, and potential of, new and more detailed studies on the distribution, mineralogy and origin of Co as well as other critical or near-critical metals in this and other ore provinces in Sweden.

KEYWORDS:

• Cobalt
• sulphide
• Bergslagen
• Sweden

Acknowledgements

The authors thank the Department of Geosciences, Swedish Museum of Natural History, Stockholm, for allowing the sampling of historical ore specimens, for which we are very grateful, and in particular for the knowledgeable and enthusiastic help of mineral collection curator Jörgen Langhof during this process. The critical review by Nils Jansson, Luleå, as well as corrections and suggestions from associate editor Magnus Ripa helped to improve the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This contribution is related to a broad project on rare and critical metals in central Swedish mines and mine dumps, funded by the Swedish Research Council (Vetenskapsrådet) to Uppsala University.