Greisen formation is associated with the cooling of a highly fractionated H2O-rich granitic intrusion and the enrichment of incompatible volatile elements in the upper part of the intrusion such as F, Cl, B and Li during fractional crystallization.

The metasomatic greisen formation, called greisenization, is defined as a granite-related, post-magmatic process during which biotite and K- / Na-feldspars became unstable (ŠTEMPROK, 1987 [153]). Subsequently to Na-feldspathization it is commonly controlled by the further decrease of the alkali / H+ ratios (PIRAJNO, 2009 [141]). Granite minerals and textures are replaced by complex aggregates of micas, quartz, topaz, and fluorite with a considerable addition of some elements such as Sn, W, Li, Mo, Be and others. Highly aggressive, Fbearing solutions induce the formation of fluoride minerals, which are compared to other metasomatic rocks very common in greisen (ROMER et al., 2010 [146]). Greisenization can affect different wall rocks. Its intensity depends basically on the texture of the protolith.

A broad range of formation temperatures between 250°C – 500 °C and pressures of 0.3 kbar – 0.8 kbar is suggested by POLLARD, 1983 [142] for the formation of greisen minerals. Latest fluid inclusion studies indicate that all elements required for the formation of the mineralization at Zinnwald were contained in a single magmatic hydrothermal fluid that underwent two main processes, fluid rock interaction and depressu ........

The ore extraction planning in the project has three targets:
- To provide constant volume and quality of ore for the minerals processing
- To economically optimize the process
- To operate efficiently without risking safety or environment

The operation has been designed for an annual output of c. 12,000 t/a LiOH. Applying the mineral reserve estimation of 3,004 ppm lithium content, and estimated Lithium recovery in downstream processes this corresponds to an average annual ore production of 880,000 tons.

The conceptual plan for mining operations is based on access from Altenberg Mine on 500 m Reduced Level (RL) advancing upwards with room and pillar, AVOCA, and sublevel stoping methods followed by hardening backfill. On production levels LHD (Load-Haule-Dump) loaders dump the mined material into ore passes from where the ROM (Run of Mine) is transported 7 kms to ROM pad downhill to Bärenstein via Zinnerz – Altenberg Mine drainage tunnel (“Entwässerungsstollen Altenberg”).

The mine is an integral part of the process tailings management as the Leach Residue from the hydrometallurgical process will be permanently located underground. This requirement has a major impact on selection of mining method and on sequencing of mine production. To prevent impacts on the surface, 90% - of void created in the ore will be backfilled.

The mine will be first accessed from two locations: From the Zinnerz – Altenberg Mine with a 4 k ........

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