Custer weekly chronicle. [volume] (Custer City, S.D.) 1890-1931, 1910-08-27
MICA IN THE BLACK HILLS
OF SOUTH DAKOT.

over to girls armed with knives. These
operatives split and trim the mica to
sizes approximating even inches. This
product is packed in barrels and boxes
for shipment to Lincoln, Nebraska. The
refuse from this department, combined
with that portion passing through the
grizzlies, goes to the grinding plant, sit
uated on lower floor. Here it is again
sorted, and that portion which will be
available for the manufacture of the
character Of washers is piled separately
from the fines. The finest portion Is
ground to powder, after being screened
on trommels for the removal of quartz
grit, etc., and is sacked for shipment.
At Lincoln, Nebraska, is located the
plant where the final trimming and
preparation for market and use is con.
Quoted. Here 500 hands, the majority
of whom are children, are employed.
This portion of the work was at one
time conducted at Custer, but as it was
impossible to secure the quantity of
operatives necessary, the work was trans
ferred to Nebraska.
At the White Spar mine, owned by
the Westinghouse Company, sinking is
now in progress below the l00-ft level.
At the 100-ft. level and above large
amounts of mica have been mined. AS
the New York and Crown mines are
large producers at present, the entire
force at the White Spar-about 80 men
lis being used in development work
One of the largest books of mica ever
mined in the Hills was taken from the
White Spar. The weight was 1852 lbs.
The quality was excellent. The White
Spar is equipped with steam hoistin ng
and air compressing plant, as we'll as a
small lighting set. Work is being car
ried forward expeditiously, and when
the 200.ft. level is reached, mica pro-
duction will be resumed. A small sort
ing and trimming house has been erect
ed. The mine is a little less than 2
miles southwest of Custer.
The Crown mine has recently come
under the control of the Westinghouse
Company after passing through num-
ber of hands. The Chicago Mica Com
pany Tin litigation) has turned the prop
erty over to the Westinghouse Compa-
ny upon that concern satisfying the
court that 1t is competent and able to
satisfy the existing judgments and en-
tanglements. The property is q miles
northwest Of Custer.
Work at this property has been largely
confined to several open cuts, the largest
of which is over 100 feet long and 25 feet
deep, with about the same width. A
vertical shaft 100 feet deep connects, by
drift, with the pegmatte at that depth.
The property is equipped with steam
machinery for mining, sorting house,
bunk house, boarding house, etc. A
good production of mica is being made
from this property, and preparations
are being made to enlarge the plant and
continue the shaft another 100 feet.
Five miles east of north of Custer is
Mine No. of the Westinghouse Com
pany. This property is being developed
by small crew. Tunnel work is under
way. No machinery has yet been in
stalled. The pegmatite is 25 feet thick,
and carries a good percentage of mica
on the walls. Mine No. 3 is 81 miles
west of Custer. A small crew is en-
ployed here on development work.
The Electrical Mica Company, of
which L. NJ. Mcbride is president and
manager, aud r. E. Mcbride is superin-
tendent, owns property l! miles east of
Sylvan Lake, and 81 miles northeast of
Custer. The country rock here is typ
ical granite, but the mica-bearing body
presents many features of banded
vein.
The vein, or pegmatite dixie, has gran
ite walls, then, on either side, a stringer
of quartz, the same of feldspar; then on
either side, the rich pegmatite which
carries enough pegmatite to pay to work.
The center of the deposit consists of the
leaner pegmatite. The deposit is len
ticular in shape, varying from 3 to so
feet in width. 1t has an east.w west strike,
and is developed by a tunnel. The COM
pany is at present negotiating for a
steam hoist and air compressing plant,
and it is hoped to start work on this in
stallation within 80 days. The company
sells it's products to manufacturers of
electrical supplies.
Numerous other properties are known
to carry mica in paying quantities, and
no doubt many of the prospects known
today will eventually develop into i'm
portant mines. 1t is confidently ex-
pected that sorting and trimming plant
will be erected at Custer in the near
future. This would be consummation
that would mean much to that section,
as it would afford them a market for
small shipments, and would without a
dout be a proposition which could be
made commercial success, in view OF
the large number of small mines from
which an immediate supply could be
drawn.
Mica mined in the Custer district is as
good as is produced in the world fol
electrical purposes, and as the manu-
facturers of electrical machinery and
accessories are the largest buyers of mica
it would seem that the mines of thi.
section are destined to be drawn upor
for large, if not the entire amoun
equal to the supply now obtained from
India and Canada.
The prima test of mica for elactrica