The White Pine news. [volume] (Ely, Nev.) 1906-1910, 1907-03-12

control such as the present level of
/ the ground water
The only primary deposits of cop
per that have been observed In the
district are limited bodies of chalco-
pyrite intimately associated with gar
net rock, or with garnet and quartz.
These primary ores occur In two dis
tinct situations, One of these Is at
the contact of intrusive rocks, par
ticularly the monzonite and monzon-
lite porphyry with the carboniterous
limestones. Here they are clearly
referable to a process of contact met
morphisfh. BY this Is meant not
merely thermal metamorphisln, but
reactionary metamorphism, whereby
solutions bearing silica and iron
from the intrusive mass react upon
the lime carbonate and give rise to
the lime-iron silicate, garnet These
same solutions appear to have sup
piled with them the materials neces-
sary for the deposition of the chal-
copyrite, and sometimes there was an
excess of silica which was precipita-
ted as quartz.
The other situation in which pri-
mary copper ores have been detect
ed is in the quartz blout, and here
again it is intimately associated with
garnet. From considerations previ-
ously set forth, it appears very prob
able indeed, if not a demonstrated
fact that the quartz blout is largely
the result of silification of the lime
stone chiefly on the periphery of the
copper bearing porphyry, but also
partly along assures in the limestone
in the vicinity of the porphyry. At
the surface, and often for considera-
Bile depths below the surface, these
donates, malachite and aZuritc. But
these carbonates are regarded as the
result of the alteration of chaicopy-
rite in stu. In other localities, par
ticularly at the Morris shaft near
Pilot Knob, and at pit near the
road between Copper Flat and Pilot
Knob, the quartz blout at depth car
ries considerable garnet with pyrite
and chalcopyrite. In the Copper Flat
mine, on the 800 foot level, there is
an extensive body of so-called dixie
of garnet rock, with nests of pyrite
and chalcopyrite. The garnet rock
is for the most part thoroughly de-
composed to a greenish or brownish
material. which, when moist, has a
cheesy consistency, and in drying on
the dump slacks in the air. All gra-
dations may lie observed between the
fresh garnet rock and the decom-
posed material.
1t thus appears that the only
traces of primary copper ores in the
district are in the form of chalcopy-
rite associated with garnet, and that
certain of these appear in quartz
blout either as the original chalco-
pN lilC vi dlLCl0u W He
hypothesis may be favorably enter
tanned that the secondary copper ore
Of the Ruth mine has been derived
from the downward teaching of cop
per from bodies and disseminating
bodies of chalcopyrite in the course
of superficial oxidation of the blout
in which they are originally deposit
ed. There are at present vast bodies
of blout at the surface Immediately
above the Ruth mine, but these are
only remnants. The greater part of
the blOut has been removed by ero-
sion. The product of this teaching
was deposited as chalconcite in the
porphyry at a time when the water
level was much higher than at pres
ent And finally when in conse-
quence of the subsistence of the
ground water to lower levels, the
zone of oxidation extended into the
porphyry, this chalcocite was in turn
/ taken into solution and redeposited
as chalcocite at still lower levels