Full resolution (JPEG) - On this page / på denna sida - VI. Mining and Metallurgical Industry. General Survey. By C. Sahlin - 1. Mining. By Valfrid Petersson
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the mining practice in swedish mines.
261
since that time has become more and more widely used. Magnetic
concentration is at present used to in some thirty concentration works. In 1913
the output of iron ore concentrates (järnmnlmslig) was 657 976 tons with
a value of 6 624 033 kronor, and since 1897 about 3 600 000 tons of iron
ore concentrate have been produced.
Besides the concentration works for iron ore there are only a few
concentration works for other ores, notably at the Åmmeberg and
Ryllshyt-tan zinc mines, at the Kaveltorp, Stollberget and Saxberget zinc and lead
mines, at Sala silver mine and others. For graphite there is a small
concentration work at Västanfors and for manganese ore concentration works
at Späxerud and Långbanshyttan.
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Magnetic Ore-dressing Plant, Långnäs mine.
Mehtods of exploring for iron ore. As most of the Swedish ores contain
magnetic iron ore methods of discovering ore deposits by the deflection of
a magnetic needle in the vicinity of magnetic ores have long been in use. In
the middle of the eighteenth century the miners compass (gruvkompass)
was constructed; with that simple instrument numerous ore deposits have
been discovered in Sweden. However, in the sixties and seventies of the
nineteenth century attempts were made to devise magnetic measuring
instruments by means of which a more exact and more detailed knowledge of
the magnetic conditions could be attained. These endeavours resulted in
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