Appendix—geological survey. 
483 
chemically pure. And the process, or processes, by which this can be done, 
are not, after all, so difficult or expensive as some people imagine. These ores 
are almost free from impurities, other than quartz, and owing to the gran¬ 
ular structure of this magnetic ore, it will yield easily to a “ crusher,” and 
when pulverized in this way, the quartz, which is only mechanically mixed 
with the oxide of iron, can be separated readily by any of the old processes 
of cleaning ores from their impurities by water. Or what, no doubt, would 
be cheaper and better, would be one of those magnetic separators, such as are 
now used in different parts of the world for cleaning ores of this kind. 
The readiness with which ore of this character can be separated by such a 
process, can be seen by any one who will take the trouble to pulverize a small 
portion of the ore, and then with a common magnet take up the oxide of iron 
and remove it to another place, continuing the process until nothing more 
will adhere to the magnet. By this simple process, he will soon find the oxide 
of iron, which is easily attracted by the magnet, in one place, while the quartz 
which will not adhere to the magnet is in another. In this way, I have exam¬ 
ined quite a number of specimens, for the purpose of finding out the relative 
purity of the different deposits, and of different places in the same deposit. 
And although I would not attempt to give the per cent, of iron in those speci¬ 
mens, not even approximately, yet any one can form a pretty correct idea of 
the proportion of quartz in a given amount of ore. 
But although these ores, that is, these two varieties, the magnetite and 
hematite, in their native condition may not be good, merchantable ores, that 
will pay to ship to any great distance, while purer ores can be obtained read¬ 
ily, they can no doubt be profitably manufactured at home, where charcoal 
can be obtained for a reasonable price. Here these leaner ores can be dealt 
with by the processes above referred to, before they are put in the furnace, or 
after they are put into the furnace by fluxes, which probably will be the 
cheaper way. When I say lean ores, I would not convey the idea that the 
ores at Black River Falls are inferior ores. On the contrary, I think, when 
separated from the quartz, they will be superior ores, from which iron of a 
superior character can be made. 
From a specimen of these ores analyzed several years ago by Dr. C. I. Jack- 
son, we have the following result: perox. iron, 67.50(47.25) metal; silica, 26.75; 
oxide mang., 365; water, 1.50. This was a specimen of the red hematite. Mag¬ 
netic ore, when freed from its impurities, contains 72.41 per cent. iron. The 
trouble with these ores, especially the magnetic, is, the oxide of iron, (that is 
the ore), has mechanically mixed with it in its granular structure, more or 
less silica in the form of quartz. The ore is good, but it is in bad company, 
from which it must be separated, either by mechanical means outside of the 
furnace, or by chemical means inside. And when we take into consideration 
the fact that, the object of supplying fluxes to the ores in the furnace is, to fur 
nish substances for which the impurities of the ore have a greater affinity 
than for the ore itsell with which they are combined, and that will in the heat 
of the process coax them away from the ore to enter into new relations, form¬ 
ing compounds that are fusible at a temperature below that at which they 
