Omaha daily bee., 1888-01-06

fbu uCUudl experience In Tin mining.
He expects TO develop and operate these
mines as soon as IL is possible TO OBJ
tain the requisite machinery and men,
The most promising and important
tin district, so far as can now be de-
termined, is that located near Harney's s
peak. Here the largest discoveries
have been made, the most work been
done, the greatest amount of capital
been expended. This region is tribu-
tary to the fourishing town OF Rapid
City, on the Fremont 4 Missouri Valley
railway, to which point the Harvey
Peak tin company will build n railroad,
the reparatory steps having already
been taken. This railroad, IA narrow
gauge. will penetrate the great tin dis
trict, winding in and out through the
canyons and leading to the pines of
Harney Peak, Hill City and Custer, car
rying in supplies and taking out ore.
Professor Carpenter in his report says
that the southern section. including the
Harney peak, Hill City and Custer City
mines, is more extensive than the
northern, but that both northern and
southern sections would doubtless have
been found one had the sedimentary
rocks been removed by erasion.
In reference to the geology of the
Black Hills, Prof Carpenter says:
From Harney peak, coming down in any
direction, one would first pass over the
upturned edge of the archTan, which con
tains veins carrying tin, gold, copper and
silver Next would be passed the rocks of
the Potsdam which in the northern hills
carry deposits of gold and silver, and in the
southern portion copper The base of it is
everywhere aurifcrous. The gold in il is de-
rived from the same source as the material
composing these rocks-viz., the archpan
area, so that the base of the Potsdam is in
reality an immense ancient placer consoli-
dated to rock.
In geological language the Black Hills
uplift is as quuquavcrsal of singular regular
ity-that is, the sedimcntary formations dip
away from the centre in all directions like
the sides of volcano.
The Harney peak tin district extends
along the easterly and northeasterly
Hanks Of the granite range above refer
red to. 1t is about twenty miles in
length by six miles in width. Within
this area several thousand miners
claims or tin lode locations have been
made.
WHERE THE TIN is FOUND.
According to the authority quoted:
The tin stone is found in granite veins or
dikcs (true tssurc vcins) in the earlier or
schistose archGan, shown upon the map, and
which vary in width from few inches to
hundreds of feet The percentage of tin
many veins carrying rock yielding from 9 to
4 per cent. That this is by no means small
percentage may be seen by the following:
In Altenberg, in SaXony, the yield is from
= to per cent. In Cornwall, as shown by
the government statistics, the yield of black
tin for the whole country is less than 2 per
cent. In the Paburro district in Cornwall,
the average of all the ore crushed IN five
years was 80 of per cent. Yet these mines
yielded fair profit.
The tin mines of Cornwall have been
worked for hundreds of years. The
miners now go down under the sea at a
distance of three thousand feet from the
surface. The expense of lifting ore and
pumping water from such Il depth must
be enormous, even with all the aids of
modern machinery. And yet when the
ore is extracted the per centum of tin
stone would seem to be very small-less
than per centum. The tin ore. cassi-
terite, of the Black Hills is near the
surface on lofty and rugged mountains
The per centum of metallic tin has been
the astonishment of Cornwall miners.
On this point Prof. Carpenter says that
he has made at the school of mines many
assays of Dakota tin ore, such as scalings
taken across veins, averages of dumps,
sample lots of ore, ETC., and has but in
one instance found less than per cent,
while the average of the ore essayed,
after excluding the evidently picked
samples, which ran 30, 40, and even 60
per cent, is about per cent black tin,
an average far exceeding that Of Corn
wall, which is, by government reports,
1.95 per cent, while the yield of the
Zwitter, in Zinwald, according to
Bruno Kerl, is about 5 per cent tin.
The English stockholders, as Lord
Thurlow intimates, are going slowly
but safely. With ample experience and
abundant means. they yet take nothing
for granted. They have had the ablest
experts in the world'to make close, per-
sonal surveys of the Black Hills tin dis
trict. They have employed old miners
to do their development work. They
have expended large amounts to ascer-
tain both the quantity and quality of the
ore, expense of mining, reduction,
freight, etc. After all this it is quite
evident that they have slowly reached
the conclusion, as Lord Thurlow says,
that Cornwall's long monopoly of twelve
hundred years Is near its end.
If this is so, our whole country, and
the world. in fact, is to be congratu-
lated. The manufacturing of metallic
tin into sheets and plates must prove a
vast business requiring skilled labor of
thousands of men.