Banská Štiavnica

The mining works under Shemnitsev during the 1700

BANSKÁ ŠTIAVNICA (EN: Banská Štiavnica; RU: Банска-Штьявница) is the polymetallic deposit within Czechoslovakia (central Slovakia), near the city with the same name. Banská Štiavnica is the ancient historical centre of the ore mining region, within which alternated the epochs of the growth and decline of the extraction. The developments of silver were conducted during the 3-2 centuries BC by the Celts, and later by the Romans. The mining works within the region have reached the greatest development during the 17th-18th centuries, when there was used the technique, which was outstanding for those times: there have been used for the first time the gunpowder for the heading of the mine workings (1627), the water lifting machine of J.K. Gell for the pumping of water, the energy of the falling water for the lifting and crushing mechanisms.

The annual extraction of gold reached 600 kilograms, of silver reached 22.7 thousand kilograms (1740). By the end of the 19th century, the annual produce amounted to 236 kilograms of Au, 5.6 tonnes of Ag, 274 kilograms of Cu, 10 tonnes of Pb.

The deposit is confined to the central zone of the stratovolcano of the Neogene age, with the prevalence of the volcanic-intrusive formation of the andesite-dacite-rhyolitic composition. The subvolcanic intrusions are represented by the diorites and granodiorites. The basement is filled by the Paleogene (conglomerates, sandstones), Mesozoic and Paleozoic (crystalline schists, granitoids) depositions. The deposit of the hydrothermal genesis is confined to the post-volcanic faults within the limits of the horst-graben structure of the caldera type. The mineralization localizes itself within the hydrothermal quartzous veins (with the length of up to 7 kilometres, the thickness of the ore columns is up to 10-15 metres, the angle of the dip is 60-70 degrees to the south-south-east), within the metasomatic altered rocks (dolomites, limestones), within the granodiorites and schists like the venules and inclusions. The main veins are the Bieber, Gruner, Shpitaler, Theresia, Ohsenkopf, and others. They distinguish the four paragenetic ore zones: Au - Ag; upper Pb - Zn; lower Pb - Zn, beneficiated with Cr; deep with Cu and rare Bi - W (scheelite) mineralization. The major ore minerals are the galena, sphalerite, chalcopyrite, pyrite, less often the sulfosalts of silver. The reserves are 5 million tonnes of ore with the average content 2.2% of Pb, 3.2% of Zn, 0.2-1% of Cu (approximately 10-15% within the Pb + Zn metasomatic ores).

The deposit is being developed by the underground mine method (the depth is 450 metres); the system of development is chambered with the shrinkage of the ore, the haulage is powered by the diesel, the issuance of the ore onto the surface is performed through the central shaft. In association with the high watering of the deposit, there has been conducted during the 17-18 centuries the adit for the drainage of the water with the length of 16.5 kilometres. For the same purposes, there is being conducted the new adit with the length of 13.6 kilometres (1981). The extraction of the ore is approximately 200 thousand tonnes (1978). At the beneficiation plant, the ore is subjected to the crushing and flotation. The flotation concentrate of lead contains 50% of Pb, 4-6% of Cu, 6% of Zn. The concentrate of zinc contains 50% of Zn, up to 1% of Cu, and approximately 1.8% of Pb.