The circle banner. [volume] (Circle, Mont.) 1914-1939, 1923-10-05
DEEPEST Mine In
TREASURE STATE
is THE GRANITE MOUNTAIN
WITH 3,770 FEET TO
IT'S CREDIT.
Forty Shafts in the Butte District
Which Are Over 1000 Feet in
Depth; Michigan Mines of Great
Depth.

| Here is some information about
the deepest mine in the world, the
deepest in the United States and the
deepest in Montana, While Butte has
40 shafts that exceed 1000 feet in
depth, the Granite Mountain of the
North Butte company is the longest
from collar to stump, the distance
being 3,770 feet. The Steward of
the Anaconda company is nearly that
depth with 1868, which is scant
55 feet deeper than the Bell, or
Diamond, as it is called by the old
time miners.
In report to the American In
stitute of Mining and Metallurgical
Engineers, Thomas F. Reed, super
vising engineer of the United States
Bureau of Mines, says:
among the large number of deep
mines in the world there are several
which do not differ much in depth"
he says: 1.-THE st. John del Rey
mine has reached a vertical depth of
6,726 feet below the top of its shaft;
miners enter it, however, through an
adit which intersects the shaft 324
feet below its top, wherefore it
might be said that the mine is real
ly only 6.400 feet deep.
"In the Kolar gold field of India
there are a number of deep shafts,
one of which reaches to vertical
depth of 6,140 feet below surface. In
South Africa also there are number
of deep shafts, the Village Deep be-
ing 500 feet early in 1921. The
City Deep, Ltd, proposes to sink to
ably by the time it does so the st.
John del Rey will be deeper than
that, since it has been increasing in
depth at an average rate of about
$50 feet per year.
"The deepest shaft in the United
States, the Tamarack No 5, although |
1t is only 5,308 feet deep, actually
approaches nearer to the center of
the earth (4,100 feet below sea level,
as against 1888 feet at st. John del
Rey). The deepest workings in the
Calumet & Hecla go down to 1900
feet below sea level.
'"The ST. John del Rey is not only
the deepest mine in the world, but it
also is worked by the Oldest regis
tered English mining company,
which was organized in 1880 to work
a mine at a considerable distance
from this one. That mine proved
and in 1897 operations
were transferred to the st. John del
Rey deposit, where operations have
been practically continuous ever
since.
"The ore deposit is remarkable in
many ways. 1t has the shape of an
enormous lima bean pod dipping
first at about As degrees, but gradu-
ally flattening to about 20 degrees in
depth, the broader axis of the pod
being vertical. The thickness of the
pod varies up to about 35 feet as a
and averages 10 or IL
feet. The total area of a cross-sec-
ton of the pod varies from 400 to !
8 200 square feet, the change being
rather gradual as it increases and
decreases.
Both the composition of the ore,
consisting of quartz, carbonate of
ron and magnesia and sulfides, with !
which the gold is apparently asso-
,iated, and the method of working I
The mine are unusual.
''It is worked" says Mr.. Reed, :
through a series of five shafts, of
which only the first reaches the sur ,
face. The others merely connect the !
evels, and strictly should be called J
wines, but it is the custom to refer !
% them as shafts in order to distin- !
suish them from the wines that are :
n the orebody; the shafts are all in
he wall rock on the north side of
he orebody and are connected whit
W crosscuts."
The method used at the st. John
lei Rey, while ingenious and success
ul, would, it is declared, be prac-
ically impossible of application to .
mines in the United States. =