Boliden

BOLIDEN (EN: Boliden; RU: Булиден) is the copper-zinc deposit at the north of Sweden. It is one of the rare deposits according to the complexity of the ores. It was being developed since the 1924 till the 1967. It is confined to the upper part of the cross-section of the Proterozoic volcanogenic-sedimentary rocks, which are dislocated and metamorphosed within the green-schistose facies of the regional metamorphism. The ore bodies are of the tabular and lenticular shape (the length is 600 metres, the thickness is 40 metres), and are controlled conformably with the stratification of the rocks by the zone of the schist forming. Two ore bodies have the vertical dip. The ores are of the arsenopyrite, quartz-tourmaline, quartz-sulfide, and pyrite types. The bodies of the massive arsenopyrite and pyrite ores are tapered at the depth of 270 metres; the quartz-tourmaline ores, which are forming the zones of the venulous-interspersed mineralization, may be traced to the depth of 570 metres. The deposit has been worked out using the underground method by the "Boliden Metall AV" company, during which process there have been extracted more than 8 million tonnes of the ore with the content (in %) 1.4 of Cu, 0.9 of Zn, 0.3 of Pb, 25 of S, and also 504 tonnes of Ag (15.5 grams of Ag per tonne), and others.