Full resolution (JPEG) - On this page / på denna sida - Second part - IX. Mining Industry and Metal Production - 1. The Iron Mines (together with information regarding other mines). By the late Prof. O. G. Nordenström - Resources of iron ore in Sweden
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RESOURCES OP IRON ORE IN SWEDEN.
689
Only a few deposits appear in the form of lodes (veins) and masses. To
this latter category may be reckoned, among others, some iron ores occurring
as lode-stocks in certain eruptive rocks (gabbro and hyperite). The best known
of these ore-deposits is the one at Taberg in the province of Småland, situated
about 11 kilometers from the city of Jönköping. It forms a mountain of 450
meters in breadth, 900 in length, and 125 meters in elevation above the nearest
surrounding country. The only ore which can be considered as real vein ore is
that which has been mined at Hesselkulla in Nerike. The country is here primitive
granite. As lode-formations we may also mention certain manganese, silver, copper,
lead, and blende deposits. Finally, pure gold has been found on lodes or
ramifications of quartz at Ädelfors in Småland and in the Falun Copper Mine. In the
latter mine, the gold occurs within the quartzite or hard-ore region, where it is
accompanied by the mineral galeno-bismuthite.
Resources of iron ore in Sweden.
The thickness of the iron ores varies greatly, partly on account of
their lenticular shape, and partly on account of the dislocations and
folds to which they have been subjected after their formation. The
thickness is greatest in the ores of the renowned ore-mountains in
Norrbotten. Thus, in Kirunavara it varies between 35 and 150 meters.
In Gellivare there are ores up to 70 meters in thickness.
Among the iron ore fields of Central Sweden, Grängesberg stands
foremost in this respect. Here the thickness of the ore goes up to 90 meters.
In the other larger ore-fields, it varies, as a rule, between 12 and 30,
and occasionally runs up to 35 meters. In most of the fields, it is,
however, less than 10 or 12 meters. With a thickness of two meters,
the ores are still considered to be worth mining. Sometimes, however,
iron ores are mined which have a lesser thickness than the last
mentioned, but this is then dependent upon quite special properties of the ore.
With respect to the longitudinal extent in the direction of the strike,
the Norrbotten ores also take the foremost place. Thus, the stock-shaped
ore in Kirunavara has a continuous length of 3,500 meters, and in the
adjacent Luossavara, the ore reaches a length of nearly 1,300 meters.
In the Gellivare mine, also situated in Norrbotten, it is true that there
are not continuous ores or ore-stocks of such great length as in
Kirunavara, but the total length of the ore-lenses here, and their intermediate
deads, in some places reaches to 7,000 meters.
In the iron ore fields of Central Sweden, which have been worked
since olden times, there do not occur ore-lenses or ore-stocks of such
very large continuous length as in Kirunavara. The most prominent
ore-fields in this respect are those at Norberg and Grängesberg. At
the former ore-field, there are ores whose length runs up to 1,200 meters;
at the latter, the greatest length is about 1,000 meters. An ore-length
of 200 to 300 meters occurs at several ore-fields.
Stceden. 44
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