The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1918-04-04
Copper Resources of Idaho as Reviewed
by Mine Inspector in Annual Report


In spite OF the fact that Idaho has
surface manifestations Of copper ore
that are probably as broadly distribut-
ed as those Of either Montana or Ari-
coma, the output of the red metal in
this state is to date, unimportant, with
a total yield in 1917 aggregating but
little over 100000 pounds. Copper
ores occur in Idaho under practically
all comparable geologic conditions at
the surface that have led to the dew
elopment OF the greatest units of pro-
states, and / confidently expect ex-
panding results in the output Of this
metal when our numerous splendid
prospects are fully appreciated and
exploited.
Copper Genesis.
The richest single center of copper
naturalization in the mining history
Of the world Is that Of Butte, Montana,
the genesis of whose magnificent cop
per ore resources occurs in an area Of
eruptive granite formation Of creta-
ceous tertiary age, known as Bould-
or Batholith, whose deepseated point
OF differentiation and subsequent rup-
turing and intrusion with more sill
cious igneous rocks is believed to be
the primary source Of the phenomenal
development of copper for which that
famous district is noted.
This interesting geologic unit, the
Boulder Batholith. Is 1900 miles In
exposed area and is not only respon-
sible for the copper deposits Of Mon
tana, but is also believed to be the
primary source Of many of the other
important ore deposits of that state
This remarkably productive granite
Batholith in Montana is a baby in the
American family of Batholith compar-
ed to an Idaho geologic unit of the
same nature, for the central rugged
mountain regions of our state contain
an eruptive granite Batholith, of the
same age as the Boulder Batholith,
that Is $4,000 square miles in total
exposed area, extensively intruded
with other igneous rocks. 1t is the
opinion of the best scientific authority
of the present day that this great
eruptive area of igneous matter Is the
mother source of practically all the
important metallic ore deposits of all
descriptions In this state of both cop
per, lead, zine and other commercial
minerals.
Around the margins of this immense
geologic unit of Idaho, which Is the
most conspicuous feature of the CEN
trail mountain regions of the state and
penetrating the adjacent marginal an-
cient sedimentary formations and ac-
companying igneous intrusives. there
ia a succession of copper ore manifest
atoms in flssure veins, contact segre-
cations and dissemination deposits
that present a number of attractive
chances and decided promise for the
development of extensive commercial
IcbOuiSSS VI pdsiib NpppSi piC.
Many of these prospects are in re-
mote districts at considerable distance
from railway transportation and have
been neglected or given little consid-
GRAFTON in the past in the way of in
telligent and warranted development,
but with this fine primary foundation
to work on, it Is not unlikely that
Idaho will become one of the import
ant producers of the red metal and
rank we'll up with its neighbors in
the future.
Empire Copper Mine.
At the present time the principal
source of our copper output Is from
the quite extensive operation of the
Empire Copper company at Mackay.
Idaho. This property carries deposits
Of the contact metamorphic type. 1t
has had a checkered cared for the
past 80 years. including the efforts of
some leading copper operators Of the
early days, under whose management
repeated failures were made to win
profit from the deposit. 1t remained
for the advancing price of the metal
and the faith of practical miners in
small leasing units to make the deposit
profitable, and establish the perman-
ency of this type or ore occurrence in
Idaho.
This property is now owned and op-
Grated by the Empire Copper company,
which is controlled by some well
known Utah capitalists. Its interest
ing ore occurrence has been fully de-
scribed in recent well illustrated
professional paper by j. b, Umpleby
of the u S. geological survey Its ore
deposits are lenzy in shape and occur
In a broad belt of formation, several
hundred feet wide, consisting of mas
sive bodies Of fine grained garnet
rock and blue heavy bedded limestone
with intrusive bikes of granite porph-
yry and quartz porphyry, This ore
bearing zone is fully 500 feet wide and
over half a mile long. Its conspicu-
Gus surface feature is a body of erup-
tive granite, with broad garnet rock
contact and massive bodies up to 100
feet thick Of magnetic iron carrying
about IL per cent copper associated |