The operator of the Cinovec project is Geomet s.r.o controls the mineral exploration licenses awarded by the Czech State over the Cinovec Lithium/Tin Project. Geomet s.r.o is owned 49% by European Metals and 51% by CEZ a.s. through its wholly owned subsidiary, Severoceske doly a.s. (SDAS).
- subscription is required.
Summary:
Cinovec is a granite-hosted tintungsten-lithium deposit.
Late Variscan age, post-orogenic granite intrusion tin and tungsten occur in oxide minerals (cassiterite and wolframite). Lithium occurs in zinnwaldite, a Li-rich muscovite.
Mineralization in a small granite cupola. Vein and greisen type. Alteration is greisenisation, silicification.
The Cinovec Deposit strikes northsouth, is elongated, and dips gently south parallel to the upper granite contact. The surface projection of mineralization is about 1km long and 900m wide.
Mineralization extends from about 200m to 500m below surface.
Country rocks in the Cinovec area comprise Proterozoic metamorphic complex muscovite-biotite orthogneiss and paragneiss, Lower Palaeozoic phyllite and epiamphibolite and partly migmatised muscovite-biotite paragneiss. These sequences are overlain and cut by the Teplice Rhyolite, composed of extrusive and partially intrusive rhyolite, dacite and ignimbrite and associated tuff with arkosic and Mid-Carboniferous coal interbeds. A thick north-south trending dyke of syenogranite porphyry up to 2km wide intrudes along or near the contact between the eastern gneisses and the Teplice Rhyolite; smaller dykes and masses are found elsewhere within the Teplice Rhyolite and basement rocks.
Cinovec is a greisen deposit.
The Cinovec tin-tungsten-lithium deposit is intimately associated with the cupola of the CinovecZinnwald granite, and comprises:
- irregular metasomatic greisen and greisenised granite zones from several tens to hundreds of metres thick that follow, and are located near or at, the upper contact of the cupola. Greisen comprises quartz and zinnwaldite with or without topaz, with irregular admixtures of sericite, fluorite and adularia-K feldspar;
- thin, flat greisen zones enclosing quartz veins up to 2m thick. Both the greisen and veins parallel the intrusive contact of the cupola, dipping shallowly to the north, south and east. Ore minerals are cassiterite (tin oxide), wolframite (tungsten oxide),scheelite (calcium tungstates) and zinnwaldite (lithium mica). In the greisen, disseminated cassiterite predominates over wolframite, while in veins wolframite is roughly equal to, or more abundant than, cassiterite;
- steep quartz veins with wolframite.
The Cinovec mineralised system represents a world-class example of a Sn/W/Li + rare earth metal district which spans the Czech-German border and is part of the larger Erzgebirge metallogenic region.
Previous mining at Cinovec, although extensive, concentrated on the high-grade vein mineralisation which in the Main part of the deposit has been predominantly exhausted. However, the mineralisation identified at Cinovec South remains relatively untouched and comprises veins as well as the more ubiquitous greisen mineralisation.