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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coal mines.
255
of iron pyrites. The Falun Mine also yields a little gold, which chiefly occurs
in solid form along with seleno-wismuthit. Copper ore has also been extracted
from the Bersbo mines at Åtvidaberg and at Nautanen in Lappland.
Manganese ore is mined at present at Späxeryd in Småland, where it occurs
in the form of lodes in the granite, and at Långban in Värmland, where the
ore consists of braunite and hausmannite, forming more or less irregular
stratiform bodies in the dolomite.
Nickel and cobalt ore were mined in ancient times in a few isolated deposits
in different parts af the country. The chief of these are the deposit of nickel
ore at Kleva in Småland and the deposit of cobalt ore at Tunaberg in
Södermanland.
Gold ore has been mined, besides at Falun, at Ädelfors in Småland. A good
quantity of silver was in former times produced by the Sala mines.
Coal Mines.
Coal is found in Sweden only in the southernmost part of the kingdom,
the province of Skåne, in seams together with fire-clays and ordinary,
non-refractory clays in layers belonging to the Rhæt-Lias system; the total
thickness of the coal seams does not exceed 1-5 meters, out of which,
however, only from 0-3 to 0-6 meters consist of coal the rest being bandes of
shales.
The coal-seams vary in numbers in different parts of the district, but only
two of them are worth mining. The beds of the coal-bearing formation are,
for the most part, in a horizontal position or very slightly inclined. Dips as high
as 20 degrees or more are rare. Nowhere have folds or sharp bends been
observed, faults, however, are quite common. In 1913 there were 8 coal-fields
in work, and from them were raised through 15 shafts 363 965 tons of coal
with a value of 2 949 032 kronor, 136 944 tons of fireclay with a value of
232 835 kronor, and 50 936 tons of clinker clay with a value of 117 753 kronor.
The principal coal mines are those at Höganäs, Billesholm, Bjuv, Skromberga,
Ormastorp, and Hyllinge.
The supply of coal in the mining fields of Skåne is estimated at about 300
million tons; out of which about 50 % consists of coal N:o 1 with average
percentage of ash up to 13 %, 40 % of coal N:o 2 with from 14 to 35 % and
10 % of coal N:o 3 with from 36 to 55 % of ash.
The Mining Practice in Swedish Mines.
Breaking Ground. Boring and Blasting. The hand-drilling was the
only method of boring until the last years of the seventies;
machine-drill-ing with compressed air begun to be introduced in the mines of Sweden, at
first at Åmmeberg in 1878 and at Falun Mine in 1879. Nowadays, after
that in the first decennium of this century light and efficaceous
hammer-drill machines, specially adopted for Swedish mines purposes have been
constructed, hand-drilling is used only in some smaller mines in Sweden.
Explosives. The explosive almost exclusively used in the Swedish
ore mines is gelatine dynamite; in recent years, however, a new explosive
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