Bleiberg

BLEIBERG (EN: Bleiberg; DE: Bleiberg; RU: Блайберг) is the lead-zinc deposit within Austria (Carinthia), near the Villach town. The deposit is known since the 1333 (first mention within the sources).

The development of the extraction was performed since the middle of the 15th century (the extraction was 270 tonnes of lead during the 1495). The intensive development was performed since the 1778. The deposit is situated within the graben with the width of approximately 600 metres, which is filled with the limestones and dolomites of the Middle and Upper Triassic, which tectonically contact with the rocks of Carboniferous and Permian along the large faults at the north side and south side of the graben. Along the tectonic disturbances, there has emerged the scaly overlap of the individual blocks of the rocks. There are ore-containing the limestones of the lower part of the Carnian stage, and of the upper part of the Ladino stage, where distinguishes itself the thick stratum (420-500 metres) of the Wasser-Stein limestones and dolomites, which contains the major reserves of the lead-zinc ores. There are known at the deposit 4 horizons of the tabular depositions, and the numerous ore bodies, which are intersecting the deposit, and are of the irregular shape. The deposit is tectonically very disturbed; there are observed in large quantity the zones of the ore breccias, which are cemented by the later mineralization of galena and sphalerite.

There exist the tabular, stratigraphically orderly depositions, which are presumably of the sedimentary origin, and the intersecting bodies of the hydrothermal origin, which are later according to the time of the forming. The composition of the ores is: galena, sphalerite, pyrite, marcasite, calcite, breunnerite, quartz, barite, and anhydrite; sometimes there exist celestite, strontianite, and wulfenite. There are characteristic the low content of silver within the galena, and the elevated content of cadmium and germanium. The ratio of Pb:Zn varies from 6:2.5 within the eastern part of the ore field, to 2:9 within the western part. The total reserves of the metals within Bleiberg are: 160 thousand tonnes of lead, 200 thousand tonnes of zinc, with the content within the ore from 10 to 1% of lead, and from 4 to 1.5% of zinc.

It is being developed by the "Bleiberger Bergwerks-Union" company (West Germany) by the underground method. The deposit is unsealed by the vertical mine shafts, and by several adits; it is being worked at the 14 operational horizons to the depth of 1000 metres. The major systems of development are: using the ceiling ledges along the horizontal layers, with the filling of the goaf space; the excavation across the strike, with the filling of the goaf space; the sublevel excavation, with the filling of the goaf space, within the bulges of the ore bodies. In case of the sublevel excavation, they slice the ore body at each 10 metres into the sublevels, which are connected by the inclined mine workings or spiral descents. At the right angle to the sublevel drifts, they cut the chambers (the width is up to 4 metres, the length in accordance with the thickness of the ore body, but not more than 15 metres). After the excavation of the ore, the chamber is filled by the concrete mixture from the upper sublevel drift. The total length of the mine workings is approximately 250 kilometres. The ore is preliminarily subjected to crushing at the underground crushing installations, and is delivered onto the surface through the vertical shaft. The beneficiation is performed within the heavy suspensions and by flotation. The annual extraction is approximately 800 thousand tonnes of the ore (1980); the production of the metals in concentrates (1981) is: 4.4 thousand tonnes of the lead ones, and 20.6 thousand tonnes of the zinc ones. The concentrates (lead and zinc) are sent into the industrial plant of the firm within the Arnoldstein city.