The Philipsburg mail. [volume] (Philipsburg, Mont.) 1887-current, 1897-07-09
AB0UY BEARMOUYH
An Excellent Write-up of That Gold
District
LOCATED IN GRANITE COUNTY
A Very Promising Field and We'll
Worth Careful Investigation
by Miuing Men.
ATED IN GRANITE COUNTY

the Mining World is probably the most
exhaustive article that has ever been
written about that district, which is
known to be one of the richest gold Sec
tions in Granite county. He says tie
Bearmouth mining district embraces
the Coloma, Deep Greek and First
Chance mining sections. The ore zone
traverses the main divide of Bear
mountains, situated between Big Black
foot and Hellgate rivers, the divide of
the mountains forming it's boundary
line between Granite and Deer Lodge
counties. These mining sections are
heavily timbered with luxuriant
growth of spruce, fir and white pine,
which in places has been burned off
and is now replaced by dense growth
OF white pine. The drainage of the
region is by tributaries to Hellgate
and Big Blackfoot rivers All of the
tributaries head aloug the main di-
vide. OF hogback, of the mountains,
which in places rise to all elevation Of
about six thousand feet above sea
level The nearest railroad station
and natural outlet and supply point
for the mines is Bearmouth, small
station Oh the Northern Pacific, about
fourteen miles south Of the central por-
ton of this mineral belt, and aoort
eighty miles northwest of Butte by
rail. From Bearmouth station a good
tion up Bear gulch to the mining camp
of First Chance, distant about twelve
miles. With the exception of few
places this road is i'll good condition
for freighting and at present all the ore
shipped from the mines is hauled owe,
it at cost Of about %3 per ton. II the
tonnage We're greater and with q few
improvements III Tie ROAD ana the
putting on of heavier wagons, this
should be reduced to at least ~. The
mineral belt which contains the prin
cipal ore deposits can be traced for
nearly ten miles in length and about
two miles in width. a prominent
feature Of the mineral belt is lime
stone ana granite contact which forms
the southern boundary OF the mineral
lied area. and although badly curved
and distorted follows the general trend
Of the main divide of the mountain
range, but crossing and recrossing from
one slope t, the other To the north
of this contact, which has a general
east and west course, is massive
granite formation, folded and faulted
into abrupt buttes and broken ridges,
while to the south is a vast limestone
region that stretches TO Hellgate river
Along the contact of the two forma-
tions the granite-which is syenite,
inasmuch as hornblend replaces the
mica-is composed of a ground mass
of light gray, thickly studded with
phenocrist of hornblend. giving to the
rock when freshly broken light gray
but weathering into IL !
dark green, and in places is badly de-
and easily eroded. From q
casual observation the limestone along
the contact seems to be of domollte
and silicose character, and dips slight |
ly under the syenite. An interesting
feature of this mineral belt is sys-
tenn of fissure veins that occur at inter
walls Of nearly twenty feet in the gran
ite, crossing the ore zone like the
round of a ladder, with strike nearly
at right angles to the course of the |
lime and granite contact, usually dip
ping at low angle toward the con-
tact, but at several places the dip is
decidedly away from the contact.
While these fissures can be traced for
several thousand feet into the granite,
at no place have they crossed the con-
tact into the limestone region. This
feature gives to the region two places |
OF ore bodies: those that occur along |
the contact in the form Of contact de- |
posits and the fssure vein deposits in
the granite. While the ore in the two
is identical in character and appear
ance. and were undoubtedly deposited
later movement of |
the mountains has left the contact
broken and distorted until no relation |
between the two can be traced The .
richest ore, which is found in chutes,
and is not continuous along the vein,
hemitlte iron ore aud is
the result of the decomposition of au-
riferous iron pyrites, which originally
filled the chutes. The fssures vary in
width, the larger one running from six
inches to four feet, the smaller ones
from mere seams to eight Inches, and
only when rich chute is encountered
have they been worked to profit. The
walls of the assures have been very
little altered and are hard aud compact.
This and the fact that the veins lay
almost fiat will materially increase the
cost of mining, as large amount of
the wall rock will have to be moved in
order to make room to work. AS a
rule the largest and richest ore chutes
are encountered in the assures in the
immediate vicinity of the contact.
Erosion and disentegration have prob.
ably cut down hundreds of feet Of the
original mountain along the mineral
belt, and millions of tons of the fiat
laying veins. and probably the best
part of them. have been swept into the
yulehes below. This gold has not been
wholly lost as it has been estimated