White Pine news. [volume] (East Ely, Nev.) 1920-1923, 1923-04-22
GEOLOGICAL SURVEY OF
COPPER BEARING TERRITORY
BY S. HERBERT WILLIAMS.

ore deposit without any attempt a
profound geology may be interesting
to those engaged in the development
of mines, particularly those who are
engaged in exploring similar depos
it's. The deposit in question is found
in the Robinson mining district. bet
ter known as the Fly district.
The immense porphyry deposits
found in the Ely district are too well
known to require a description here
having been examined by the United
States geological survey, professional
paper No. 90. A. c. Spencer geolo-
gist. Briefly, they consist Of a por-
phyry intrusion having an east and
west strike. The copper yield of this
immense deposit may be given at one
and one-half per cent copper with
precious metal values below dol
lar per ton.
Nearly all of the copper ore pro
duced in this district has been con-
fined to the porphyry, but there is
no question but what a large tonnage
of %high-grdae ore, better known as
contact ore, will be found at the con
tact of the lime and the porphyry.
1t is generally conceded that the
contact ore rhinestone, receiving its
value from the intrusive porphyry)
will prove to be an important eouree
of copper as deeper developments
are attained and more attention is
given to this class of mining. Up TO
the present time little or no atten-
ton has been paid to anything 5u,
the porphyries, because tonnage was
the principal factor.
Ely, like many other mining dis
%tricts, produces varied mineral ie-
posits, including zinc and manga
nese, and, as frequently happens, the
ores from the different mines bear
no resemblance to each other. For
instance, the ore from what is known
as the Veteran mine is entirely dis
tinct in appearance, color and com
position from that found in the adj
Joining property known as the Con-
solidated Coppermines, the latter
having a distinct zone of ore con-
tanning 1920 per cent of A1-2 O-3,
with a copper content of 8 per cent.
In making the above statement /
am not referring to the porphyry de-
post of the Coppermines which ad-
joins the similar deposit of the Ne
vada Consolidated. The above ore
bodies are located in the western
part of the district, which is about
seven miles long.
An examination of the surface
groupings of this district shows a
siye gossan or iasperoid groupings
miles, some of which with a little
surface work yield copper c~arbonates
frequently rich enough in copper TO
ship direct. The groupings are mas
sive and generally lay Immediately
above the ore deposits. In many in
stances there is a remarkable rela.
ton between the groupings and ore
bodies Immediately beneath. This is
particularly noticeable at the Alpha
group of the Coppermines and, SO far
as developments have advanced, in
the Mitchell tunnel of the Boston and
Ely Consolidated Mining Company.
The groupings on the Ely Northern
Copper Company are very dark-red
or black in color and are highly
silicifed. The shading is from dark
red to black. Partial analysis of
groupings from a limonite deposit:
Insoluble. 1881 per cent; iron.
1921; lime, 6.19; zinc, LA: lead,
2.65; gold, .o4 ounce; silver, $50
ounce.
The prominent red to dark red
groupings found over the ~porpbyry
and other sources of ore in the west.
erly part of the district are not found
in the Ely Northern Copper Com
pany. Partial analysis of groupings
over known ~porphyry ore-bodies:
No 1: Insoluble, 94.10 per cent;
Gao, LIS; Fe., 2.G2; Gu, non
No. 2: Insoluble. 92.9G per cent:
Gao, 2.09; Fe., 3.37; Gu, none.
Situated in the eastern part of the
district on property formerly known
as the Ely Northern Copper Company
and now owned by the Boston and
Ely Consolidated Mining Company,
Is a deposit unique in its occurrence.
1t is locally known as limonite. Tho
mass on the tunnel level has a length
of 200 feet and a width of so feet.
the limonite continuing southwest
erly for an additional hundred and
fifty feet with a width of from five to
twenty feet yielding small quantities
of copper the entire distance. The
limonite itself has from 40 to so
per cen iron (hematite) and insol-
ubles from an ochrc yellow to a
dark-red and dark-brcwn and fire.
quently concretionary. The eoncre-
tionary structure is sometimes very
noticeable IN the ore deposits, which
exhibit alternate showings OF copper
and limonite up to a foot In diam
eter. Cavities or vug are frequent
ly found up to one foot in diameter.
usually lined with a hard hematite.
Several water courses have been