Santa Fe new Mexican. [volume] (Santa Fe, N.M.) 1898-1951, 1900-12-13
ABOUT MICA AND
MICA MINING
There is a Large Increase in the Oonsump'
tion of Mica Due to Its Use in
Electric Work.
REQUISITES FOR COMMERCIAL MICA.

(The Engineering and Mining Journal.)
Among the minerals of minor econom-
ical importance, none seems to nave at
tracted more attention recently than
recently of inquiries with regard to the
possible value of mica deposits, and of
reports of the discovery Of such depos-
it's in all parts of the country. Unfor-
tunately, most of these reports are
based on mistaken ideas in relation to
the mineral, and urn out to be of little
or no value.
There are two or three probable rea-
sons for this general interest. The first
is the large increase in the consumption
of mica due to it's use in electric work,
n the consequent rise in price. The
second is that mica is very widely dis
tributed, and is of very common occur-
renee; though, unfortunately, it is
found in very few places in large. guam
titles or in such form as to be of COM
mercial value. Another reason, perhaps,
is that very few are practically ac-
quainted with mica mines and their
workings, and are, therefore, liable to
be deceived by indications which the
experienced mica miner would at once
see to be of no value. A few words on
this mineral may be of service to the
many who seem to be in search of it.
The first requisite for commercial mi
ca is the size of the blocks from which
sheets can be split. In addition to this
the sheets must be free from cracks and
flaws Of all kinds, must be fairly even
in thickness and not too brittle. For
merly good color was also a prime re-
quisite, and this is still the case for GER
tain kinds of work; but for electric
work, if the other requisites are met,
color is of minor Importance. The ex-
ception is the dark red or rusty color,
which indicates the presence Of iron as
an impurity, which impairs it's %insulat-
ing properties. 1t may be of interest to
prospectors to note that experienced
miners say that where the blocks of mi
ca are checked, split and cracked on or
near the surface, there is seldom any
improvement in quality with depth.
The mining of mica is not usually a
difficult operation. In those mines
which are now worked hand labor is
chiefly employed; and the preparation
for market is chiefly done by hand la
Dor also, the tools used being few and
simple. 1T is due to this that the mines
of India, where hand ~labor-usually
de%Xterous through long practice-is
paid at very low rates, are able to sup
ply other countries at prices which meet
competition everywhere. The prepara-
ton for market is comparatively sim
pie, consisting only in freeing the blocks
of mica from the gangue in which they
are found, and splitting them into
sheets. The waste in mining is very
great. The mica is usually found in peg
MATTE bikes, which occur in gneissic or
granite rocks. In some instances in
this country the mica constitutes as
much as 10 per cent of the total mass
of the dixie, but often it is less than 1
per cent. The quantity of waste rock to
be handled is, therefore, very large.
Moreover, of the mica taken out, the
proportion which has a commercial
value as sheet mica varies in our best
mines from 2 to 10 per cent, seldom APP
preaching the higher proportion.
There are no b~y-products in mica
mining, except the scrap. In it's usual
scrap form it's value is small, but when
pulverized there is a certain demand for
it. AS a fine powder it is compressed
and used in some forms of insulators IN
electric work. In powder it is also used
in making some kinds of paint, in man.
ufacturing wall paper, as an absorbent
in making dynamite and in making lu-
bricants for large and heavy bearings.
1t will not, however, pay to mine small
or scrap mica to pulverize. The supply
is large already, and it can only pay
to grind and market the mica powder
when the sheets meet the chief expense
of mining.
We do not wish to discourage the
search for this mineral; but it is GER
tainly Of advantage to prospectors to
understand what they can expect from
a deposit, and how much time or labor
it is worth while to spend in looking
for it.