The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-07-18

east. and in only two Individual in
stances does their strike epaIt as
much as Is degrees to the north or
south Of an east-west line. In
the Butte district. while In individual
mines or rou of veins Il h gener-
ally possible to distinguish two prevail
ING directions OF strike. the one to the
north or east. tho other 10 the south OF
east. Il is not possible to say that IN
all cases the assuring I'm one OF these
directions is so much stronge than
that in the other as to be called the
major direction.
THE direction Of veins I'm vertical
planes. or their dip. Is even more uni
form than their strike. The veins to
the north Of the Alice mine. including
the north vein of the lode.
stand either vertical or with q dip or
so to So degrees TO the north. South OF
this line. with but one or two excep-
tons. the divergence from the vertical
is 10 the south. and not more than rs
degrees. except in the region to the
west Of the Butte. The angle between
the two directions OF dip then may be
taken as an average OF * degrees, and
a maximum of 81 degrees.
The term ode is used In this text
"a denote a c~o-ordinated system Of min
eralized assures. nearly parallel. and
generally separated by bands Of more
or less barren country rock. a lode
nay be bout 100 feet wide and IL may
not be over 10. When more widely
spaced veins are spoken Of. which yet
need to be c~o-ordinated. the term vein
system is used. The individual veins
on the other hand may be. and in this
district generally are, made up Of a
number of closely spaced fractures.
The space between the outer fracture
planes may he occupied by alternating
bands Of country rock and of vein ma
terial. or by more or less altered coun-
try rock through which run many small
cross-fractures or joints filled with vein
material. or II may be entirely occupied
by vein material. In the latter case IT
Is impossible to determine how many
fracture planes may have been origin
ally developed. In n few instances the
space is filled by a breccia, or broken
fragments of country rock, cemented by
vein material.
There is observable In the tracing
OF the veins a tendency to wrap around
the co~pper-bearing area, which is also
that OF most abundant ore deposition.
n may be regarded in a broad way as
the center of naturalization. 1t is
more noticeable on the north side Of
this center than on the south. which
may be due TO the fact that the veins
are not so extensively traced In the
latter direction, as the rock surface
is for the most part buried under the
alluvium Of Silver Bow valley, n
existing mineral developments have not
encouraged underground exploration.
This tendency was remarked early In
the history of the district. and gave
rise to the designation Rainbow lode.
applied to the systems of veins run
ming through the Moulton and Alice
claims. 80
THE economically valuable ores of
the Butte district are found exclusive
ly in the older rocks-granite, aplite or
/ ntIa MT nnrnhNT few nrOSnRCtinR
shafts have been sunk on what APP
reared TO be veins within the area OF
the more recent rhvolite intrusion. but
these i'm most cases have been proved
to be vein-bearing ridges of the older
rocks. from which the everything rhyo-
lite has been more or less completely
denuded.
The copper ores are found only in
the granite. which is a very basic va
riety, but Of remarkably uniform chem
teal composition, The silver ores. on the
other hand. occur indinerently In the
basic granite or the very acid aplite.
but are less extensively developed i'm
the areas of the latter rock. "
QuartZ-porphyry, which IL Of relative
~ subordinate geological Importance. is
found only in the copper area, and I'm
dike-like bodies which preserve a gen
eral parallellsm with the veins. .
From a commercial point OF view,
the deposits are divisible into two dis
tinct classes. the silver deposits and
the copper deposits. both of which con-
tain a small proportion of gold values,
which locally are so concentrated I'm
certain silver deposits as to constitute
an important part of the product.
Internationally, the distinction be-
tween these two classes OF deposits is
less sharply defined, for the copper
veins always carry silver, and many
were originally opened as silver mines,
while toward the west in most of the
veins there Is n gradual decrease I'm
copper-bearing minerals, so that the
ores finally become more valuable for
silver and gold h for copper. .
No copper-bearing minerals whatever
are known to occur In the areas west
and directly south of the Butte.
I'm the western part of the copper
bearing areas. on the line of Main
street. the copper veins separate into
two distinct belts or groups, between
which lies In intermediate group of
silver-bearing veins. and a little far
Their east a series OF barren veins. The
northern belt consists OF the Syndi-
cate lode. on which are situated. com
mencing from the west. the Moscow.
Poulin, Buffalo. Mountain Con, Green
Mountain and Wake-Up-Jim mines.
Further east II Is = multiple system
of veins. consisting OF the Spectator,
Bell and High ore veins. I'm the East
Gray Rock n Bell mines. On the east
slope Of the hill II consists of the Mo-
doc vein alone, in the mine OF the same
name.
THE southern belt commences on the
west with the Gagnon-Parrot lode
which has been traced eastward
through the grounds of the Original
Parrot, Anaconda and Pennsylvania
mines. To the north OF this Is thu
Anaconda lode, which eastward ira
verses the Mountain View and Rarus
grounds. Still farther north are veins
of the Mountain View lode, the north.
ern of which in the Colusa ground
crosses the line OF the Modoc vein ex.
: tended. South OF the Parrot the Moon.
light lode runs from the Blue JAY
Z through the Moonlight, Pennsylvania
and Silver Bow mines: and stilI far
: ther south, at the base OF Anaconds
. Hill, the Ground Squirrel lode has beer