Investigation to determine the Content of Tin and other Trace Elements in Grängesberg Ore

This paper deals with the contents of certain trace elements in the Grängesberg iron ore, especially the content of tin. Earlier geochemical investigations have shown that the ore possesses an anomalous content of tin. It was supposed that most of the tin occurred in cassiterite. In order to find out if any part of the ore body contains tin of economic interest, sampling has been performed mainly on the 350-to-385-m level and core samples have been taken from the 800-m level. Altogether 64 samples from ores and rocks in the Grängesberg .field and 15 samples from ores and granites in the surroundings of Grängesberg have been sampled. A description of the sampling methods and the treatment of the samples is given. The results of the investigations show that the ore has a fairly uniform tin content, with an average of 105 g/ton. Compared with other iron ores in Sweden, this is an anomalous content. An uncertain connection can be traced between pegmatiteintrusions and the tin content. The tin content in rocks is normal compared with similar rocks in other districts. The possibilities of tin occurring in other minerals than cassiterite is discussed. It is shown that some of the magnetite fractions contain as much as 50 g/ton. Beside tin, analyses covering the elements Fe, Mn, Ti, Cu, Pb, Zn, Cr, Ni, Mo, W, Ba and Co have been made on rocks and ores. A few samples have been analysed for P and V. The conclusions of the investigations are that the tin content in the Grängesberg ore is not of economic interest in any part of the ore body. But it may be worth mentioning that the ore and the ore products produced yearly at Grängesberg contain about 315 tons of tin. The other elements are briefly discussed and the percentages are compared with the normal abundances. The figures from the analyses of the oresamples have been processed in a computer and correlation and factor analyses have been made.