The White Pine news. [volume] (Ely, Nev.) 1906-1910, 1908-07-01
THE FUTURE OF THE
G0LOF|ELD DISTRICT


small acreage covered by the Cold
field Consolidated and Florence
properties has, during the past three
years, been so extraordinary for a
new district, that the attention of
investors and operators has been very
closely centered upon IL, and to the
neglect of belt laing east OF the
Red Top, Mohawk, and Jumbo mines
that seems worthy of more serious
development than has been attempt-
ed says the Mining and Scientific
Press.
The region in question differs from
that of the proved belt by reason OF
fault, noted by Ransome In his
monograph on the geology of Gold
field. this fault strikes roughly
north-south and to the west of the
ST. Ives and Velvet properties West
of this fault. and extending TO the
Columbia mountain fault, is an area
of dacite which has not been bottem-
ed in 500 feet. the deepest workings
In the Mohawk mine and in the dis
trict. East of the fault and extend
mgr to the granite of Nindieato
mountain. is an extensive area, over
part of which dacite appears at the
surface This dacite is of shallow
depth-from 100 to 200 feet-and
is underlain by sheet of the early
andesite of the region. This, iii turn,
at depths varying as far as observed
from 200 to $50 feet, is underlain by
second sheet of dacite. The impor-
tanee of this fact, from geological
viewpoint, is great. The commercial
possibilities can be appreciated only
by those who know the relative value
of daeite among the country rock of
the Goldfield district. OF the rocks
named only three need be here con-
sidered: The earlier andesite,
whitish-gray containing much horn
blende and thereby readily dis
velopment; the later andesite. dark
country rock west of the Columbia
mountain fault. and in which no
payable veins have so far been found
at Goldfeld in spite of much de-
velopment: the later andsite, dark
gray. with phonocrysts of feldspar
and with a fairly smooth cleavage;
and dacite, similar chemically to the
later andesite but distinguished by a
rough cleavage. the presence of oc-
casional quartz phenocrysts. and a
lighter color when weathered. The
first of these rocks has apparently no
commercial importance whatever.
The second has possibilities, as in
dicated in the Daisy mine at
Diamonddeld The third. dacite. is
the country rock of the Mohawk
Red Top, Combination. Jumbo. and
Florence mines IL Is sufficiently
obvious that operators at Goidield,
having before them the remarkable
yield of these mines, should seek TO
develop veins occurring in the same
country rock and close by. That this
has not been done more vigorously
is doubtless due to lack Of UNDER
standing of geology of that part of
the district.
In the belt with which this article
particularly deals, several properties
have yielded pay ore, some of ii rich,
from veins that continue downward
strongly as far as developed-bnt al
ways. with one exception. from near
the surface. Among these properties
are the St. Ives, Velvet. Blue Bell,
Blue Bull, North Star, and Cimmaron
Always the ore ceased. or nearly so,
as the undertaking andesite was ap-
preached. The exception is the ST.
Ives, where both the mine and lease
shafts have penetrated the lower
daeite, wherein, am ereditably In
formed, high grade ore has again
been found. This is the sole evidence
so far that this lower dacite sheet is
of the same character as that of the
Mohawk-Florence belt, but it would
seems sufficiently good evidence TO
courage owners of neighboring
claims covering strong veins to de-
velop deeper into country that is
favorable Heretofore, operations
have generally ceased as surface ore
failed. In some cases, large sums
have been spent in developing veins
within the andesite sheet at depths
of from 200 to 800 feet with entirely
negative results. A like expenditure
at depth of 500 feet might possibly
have developed good mines.
The dacite of the Goldfield district
is later than the first andesite and ar~
pears as intrusive sheets. lying rather
fiat and presumably following lines
of weakness. Ransome notes a single
such sheet, which appears at the
surface, and the underlying first
andesite. The lower dacite sheet
does not come to the surfce anywhere
but is shown in the several shafts,
the most westerly of these being the
st. Ives and the most easterly the
Old Kentuck. near indicator
mountain. How thick this lower
sheet may be there is as yet no
evidence; but that it is of the same
origin as the upper sheet. thrown off
from the same more or less vertical
ihstrusion. l can see no good reason
to doubt. II follows, logically. that
there may be several such sheets
separated by the older country rock.
1t also follows that IL Ransome S
north-south fault is normal as il
probably is. the first andesite of the
St. Ives will be found to underlie the
dacite of the Mohawk and Florence
mines at depth yet to be deter
mined. In such event there will he
consolation in the fact that lower
.