Custer weekly chronicle. [volume] (Custer City, S.D.) 1890-1931, 1897-03-06
Our Potsdam Gold Ores.

The New York Engineering and Min
ing Journal, in a recent issue presents
the following brief summary Of very
interesting paper on the Potsdam gold
ores of the Black Hills by Prof. Frank
Clemes Smith, of the State School of
Mines, which was presented and read at
the late annual meeting of the American
Institute of Mining Engineers in Chi
cago:
after describing generally the geolo-
gy of the Black Hills region, the author
says that the gold ores Of the potsdam
constitute group of much greater i'm
portance than all of the other silicious
ores together. Most of these cres may
be described as thoroughly reorganized
sandstones, containing quartz crystals,
calcite and fluorite. Those which have
not been oxdized carry considerable
fine grained pyrite and are locally called
blue ores the OXidjzed ores are stained
with iron and called red ores. Analyses
of typical samples of red ore show S.4
OF. telurium, 0.07 OF gold and 2.SS OF
silver to the ton of blue ore, 4.03 or.
telnrnm, 003 or gold and 10 55 OF.
silver to the ton. Copper is usually
found in traces. The occurrence Of these
ores is widespread but eccentric. The
naturalization is to be referred to
igneous action.
Recently gold ores have been found
in the carboniferons limestone near
Ragged Top, at first in boulders and
later in wedges shaped lenses. An ana
lysis of this ore f. ON the Dacy showed
20 23 OF. tellurium, 1874 OF gold and
l.2l OF. silver per ton. Scattered
through the limestone are many fiinty
nodules said to be rich in gold. aLa 70.
"The history of the potsdam ores dates
from 1877, when several mines were To-
Gated near Green Mountain. A mill Wis
put up in 1876. but did no, succeed IN saw
ing the gold. Various processes were
tried with very little success. In 1856
the Golden Reward company put up a
cnlorination plant and later cyanide
plants were tried by the Black Hills
Reduction company and the Deadwood
& Delaware Smelling company. While
it formerly did not pay to work these
ores for less than $50 per ton, they will
now return profit on SIS. Mining is
usually not expensive in the ore bodies.
Chlorination and cyanide lixivation
have developed into considerable in
dustries in the district.
The tonnage of potsdam ores treated
is rapidly increasing; i'm 1896 there
were abont 2S2, 900 tons, of total value
of over S5000,000. Besides the main
connected area, there are several small
er and disconnected areas of these ores
in the reighborhood of Deadwood and
Lead City. In these there are some
valuable mines. At Galena, II miles
southwest Of Deadwood, an old camp
abandoned some ten years ago, has re.
Gently been revived and smelter is
actively at work. These mines are in
the potsdam ores, evidently miEeralized
from igneous dikes. This district has
not heretofore received much attention.
Another description of ores which
may be classed rs potsdam ores are the
conglomerates found between the base
Of the potsdam and the archean. They
have been worked foi years near the
Homestake ontcrop and at Rorkerville,
in Pennington county. They are, how
ever, simply placer deposits in which
the gold is chiefly free"