Li-Co-Ni-Mn-REE veins of the Western Erzgebirge, Germany - A potential source of battery raw materials

Situated in the western Erzgebirge metallogenetic province (Vogtland, Germany) the Eichigt prospect is associated with several hydrothermal quartz veins that are exposed at surface. Bulk-rock geochemical assays of colloform Fe- and Mn-oxide aggregates associated with these veins yield high concentrations of Li (0.6-4.1 kg/t), Co (0.6-14.7kg/t) and Ni (0.2-2.8 kg/t), as well as significant quantities of Mn, Cu and light rare earth elements, a very unusual metal tenor closely resembling the mixture of raw materials needed for Li-ion battery production. This study reports the results of a first detailed investigation of this rather unique polymetallic mineralization style, including detailed petrographic and mineralogical studies complemented by bulk rock geochemistry, electron microprobe analyses and laser-ablation inductively-coupled massspectrometry. The mineralized material comprises of an oxide assemblage of goethite and hematite, hollandite and lithiophorite that together cement angular fragments of vein quartz. Lithiophorite is the predominant host of Li (3.6-11.1 kg/t), Co (2.5-54.5 kg/t) and Ni (0.2-8.9 kg/t); Cu is contained in similar amounts in hollandite and lithiophorite whereas LREE are hosted mostly in microcrystalline rhabdophane and florencite finely intergrown with the Mn oxyhydroxides. 40Ar/39Ar ages (~40-34 Ma) of manganomelane link the polymetallic oxyhydroxide mineralization to geothermal
activity associated with Cenozoic opening of the Eger rift system. A low temperature hydrothermal overprint of pre-existing base metal sulfide-quartz mineralization on fault structures that were reactivated during continental rifting is thus identified as the most likely origin of the polymetallic oxyhydroxide mineralization at Eichigt. A mixture of metal remobilization from precursor metal sulfide mineralization and/or leaching of crustal rocks may have given rise to the unusual metal tenor.