The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1913-10-02
ECONOMIC GEOLOGY Of
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Continued from Page y
gulch. about half a mile north of the
South Fork Of the Occur dAloue river.
The workings of this mine consist of a
main adlt on the 10U-foot level. 20a,
400 and o0-foot levels. a shaft and a
short surface tunnel known as the
Mud tunnel At the time of visit the
600 foot level was inaccessible because
of water in the shaft. The mine IS
worked from the shaft. the tunnel on
the 1OO-foot level being boarded up
and apparently long in dsuse, The
tunnel. however. affords an interest
ing geologic section, 1t starts south
of the Osburn fault, which 1t crosses
about 300 feet from the entrance. Up
to the fault the tunnel is driven In 4
banded blue and black shale interbed.
ded with quartzitic layers belonging
to the Newland (Wallace) formation.
Toward the fault the formation. which
near the tunnel entrance presents
fairly regular dip, becomes crushed.
folded and faulted North of the fau.
the tunnel enters into hard brecciated
Iquartzite. which Is thought to be Re-
vett Here again the characteristics
of the formation are somewhat mask
ed by shearing. brecciation and silici-
hcation. All the other workings of
the Alice mine are situated north of
the Osburn fault ON the 400-foot level
two drifts have been run to the fault
but at the time OF visit the loose
inaccessible
The ore occurs In three veins or
more properly breccia ted zones in the
ouartzite These veins are known as
the Alice, Mary j., and Mud tunnel
The Alice and Mary ]. veins are APP
proximately parallel to the Osburn
fault but the Mud tunnel vein makes
a small angle with the Mary j. These
brecciated zones are of no great per
sstence along either their strike or
their dip. Numerous small faults and
slips run through the brecciated
ouart8ite in various directions. Some
of them cut the ore off sharply, or the
deposit may be limited by two inter-
secting slips, which are the walls OF
the vein. The Mary j. vein, which has
been stopped on the 100 and 200-foot
levels, has not been disclosed by the
development work on the 40O-foot
I,,,,,l bn tlrncl yaln which is
; exposed in the short surface tunnel
and on the 100 foot level, has not been
, encountered in the lower workings.
The workable parts of these veins are
of small extent, the ore occurring in
? punches or lenses. The Alice vein, for
], instance, which on the main level has
been followed for over 1000 feet, has
been stopped in but two places, one
! Slope being about 100 feet long and
of slight vertical extent, and the other
!, a very small stope in which the ore
, was extracted from the trough of tvs
: intersecting faults. The Mary j. vein
> has been stopped for distance OF lot
/, feet along the strike and through 4
vertical distance of 95 feet. Other
.stopes have been made on the severa
> levels A stope on the Alice vein or
= the 4OO-foot level is said to have pro
$ duced ore to the value Of $4,000.
The ore deposits in the brecciatec
: zones consist Of metallic sulphides ano
7 quartz veins The principal sulphidt
4 is galena but green stains on the walls
. indicate the presence of copper. IN;
, galena occurs both as replacement de-
t posts and as narrow iissure illlings u
f the brecciated uuartzite. 1t does mi
: seem to be a constituent OF the quartz
veins proper, although secondary silica
$ il prominent in the mineralized zones
l In places the ore bodies are from IL to
., IA feet wide and have lead content
. of per cent. Cerusite is another ore
5 mineral of these deposits and prob
ably EQUALS the galena in amount. The
, mineral owes its presence to the por-
, Gus nature Of the brecciated quartzlte
l II was noted on the 400 foot level and
is said to extend to the deepest work
, jpgs. Siderite does not occur in the
!, mineralized zones, the Alice being The
; ONLY lead mine in the Occur dAlene
: district in which siderite Is not an
, abundant gangue mineral
= Several periods of movement are ap'
; parent i'm the mineraized zone IN the
Alice mine. An idea of the disturb
: ances accompanying and subsequent t
E the naturalization is best gained by
study of the Mary j. vein on the goo
foot level The vein is about II zee,
= wide in the center of the Slope pu'
/, narrows toward the east and west
' ends. The north wall Of the vein Ii
"A sickensidcd plane trending north
= 60 degrees east and dipping 80 de-
: grees south. Against this wall mar
row seam of black gouge shows grount
- galena, then follows a barren quart
vein about two feet thick, and next Is
the ore, consisting of brecciatat
. Iauartzite in which occur seams OF ga
lena and its oxidzed products, aloni
= with the secondary silica. On thu
+ south wall another slip dips to th'
d north and strikes in such a direction