The Grangeville globe. [volume] (Grangeville, Idaho) 1907-1922, 1918-09-19

NHulor Note-lhe accompanying
article on the gold fields of Central Ida
no, was written by Dean Francis A.
Thomson of the University Of Idaho
school of mines, following recent tour
of the Idaho county mining district.)
Central Idaho, including the old
placer camps of Warren, Florence,
Elk City, Pierce City, Newsome, Oro-
grande anu Dixie, stands out as one
of the great placer gold producing
aceas of western America. While de-
tailed statistics will probably never be
available it is the writer's belief that
the actual production lies between $780,
100000 and $3.50, 100000; in any event
sufficient is known to justify the state
ment that Idaho county takes rank as a
placer gold area second only in modern
times to the placers of California, of
the Raser river, of Australia and
Alaska.
1t is of course, an oft proven fallacy
that great quartz gold mines will nee
essarily be found at the source of the
placer gold, but on the other hand no
instance is recalled of a great gold
placer which does not have somewhere
adjacent to it a lode gold district, not
necessarily perhaps as the source of the
placer gold, but probably of contem-
poraneous age and apparently deposit
ed by the same system of mineraliza-
tion as were those deposits from which
the placer gold itself was derived. This
has been true of all the areas mentioned
and it is true of central Idaho, and
upon the lode or quartz mines of cen
trai Idaho the mining future of the
region depends, for placers are neces.
sarily ephemeral and soon exhausted.
The question that naturally arises,
is if central Idaho can produce lode
gold why does she not do so9
Thomson Tours Central Idaho.
In order to attempt an answer to
this question the writer spent the
major part of August in an investiga-
tion of the area under discussion. The
camps visited in order were Buffalo
Hump, including Concord and Calan.
der, the Orogrande, Elk City and ada
the Ten Mile district. In all of these
the important typical and best devel
oped properties were visited and
studied. While systematic detailed
sampling was obviously impossible, re-
preventative samples were taken as prac
tically all properties sufficient to give
at least a qualitative estimate of the
value of the ore exposed. In addition
sampling data collected by other engi
reers, mill and smelter returns and other
data were made available for my in
spection and reference.
Geologically the country, as is well
known, is part of the great Idaho gran
ite batholith, which, upon its edges il
flanked by schists, gneiss and Other
metamorphic rocks. Large and small
inclusions of these metamorphics form 6
prominent geological feature, the Ell
City area lying almost wholly within 6
gneiss inclusion of this type.
The gold deposits are of two types
The first type includes the normal
typical, quartz veins, which are char
acteristic of large masses of ganitit
rock. These veins may be large o.
small rich or poor, continuous or dis
continuous. In central Idaho an aston
ishingly large number of them arr
mineralized, that is, they show pyrit'
or other sulphides commonly associat
ed with gold, or where oridized, tn,
characteristic residues from these sui
phides. These typical quartz veins oc
cur both in the granite and in the gneiss
Nearly all of them are gold bearing an'
the production of lode gold from thi
region has come almost entirely from
this type of deposit.