Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1918-09-19
THOMSON WRITES
ON IDAHO COUNTY
COLD FIELDS
DEAN OF UNIVERSITY SCHOOL or
MINES PREPARES INTEREST
ING ARTICLE
NONE BETTER IN WORLD
Local Region Compares Favorably With
Those Of California, Australia
and Alaska

I, EDITORS Note-The accompanying
2 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 a recent tour
of the Idaho county mining district.)
Central Idaho, including the old
placer camps of Warren, Florence,
Elk City, Pierce City, Newsome, Orc
grande and Dixie, stands out as one
of the great placer gold producing
{ aceas Of western America. While de-
tailed statistics viii probably never be
available it is the writer IS belief that
the actual production lies between $780,,
} 100000 and sl5O,OOO,OOO; in any event
sufficient is known to Justify the state
ment that Idaho county takes rank as
placer gold area second only in modern
times to the placers of California, of
the Raser river, of Australia and
Alaska.
Quartz Follows Placer Mining.
1t is of course, an oft proven fallacy
that great quartz gold mines viii nee
essarily be found at the source of the
placer gold, but on the other hand no
instance is recalled of 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-
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
trail Idaho the mining future of the
region depends, for placers are neces-
Ssrily ephemeral and soon exhausted.
The question that naturally arises,
is if central Idaho can produce lode
gold why does she not do 500
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 |
cent camps and Dixie and Golden or
the Ten Mile district. In all of these
the important typical and best devel-
oped properties were visited and
studied. While systematic detailed
samphng was obviously impossible, re-
preventative samples were taken as prac-
tically all properties sufficient to give
at least qualitative estimate of the
value of the ore exposed. In addition,
data collected by other engi-
peers, mill and smelter returns and other
data were made available for my in
spection and reference.
Geologically the country, as is wen
known, is part of the great Idaho gran
tie batholith, which, upon its edges is
Thanked by schists, gneiss and other
rocks. Large and small
nclusions of these metamorphics form
prominent geological feature, the Elk
ity area lying almost wholly within
gneiss inclusion of this type
The gold deposits are of two types.
The first type includes the normal,
typical, quartz veins, which are char
lcteristie of lafge masses of ganitic
oek. These veins may be large or
mall, rich or poor, continuous or dis
ontinuOus. In central Idaho an aston
shingly large number of them are
mineralzed,' that is, they show pyrite
T other sulphides commonly associat-
d with gold, or where Oridized, the
residues from these sui
hides. These typical quartz veins oc-
II both in the granite and in the gneiss.
'early all of them are gold bearing and
be production of lode gold from this
sgion has come almost entirely from
his type of deposit.
The second type, known locally as
he dixie" deposit, is somewhat less
ommon, and while not responsible for
much of the lode gold so far produced
nay prove eventually to be the more
important. these dykes or zones are
nainly pegmatitie in character and con-
am frequent narrow ribbons of vein
nartz together with interlacing vein
cts of iron oxide, doubtless derived
rom pyrites. The felspar in the dikes