National Republican., 1883-05-18
A MICA MINE IN MARYLAND.

lIHsb Wetk n Nlslb WIS udub 10 bnb mOnI-
gomery county Nd, mica minos sltuafcd
twelve miles from Washington, near the Cole
willie pike and on tio northwest fork of tho
Potomac. Something over a year ago It was
reported by farmer in the vicinity to Gen.
G. d. Gilmore, of this city, that valuable de-
posit of mica existed ont certain farm.
Gen. Gilmore, owning somo land in the vi
cnity, visited the designated locality and
found n deep.cut ravine, in which tho mica
vein was plainly visible. The result was tho
purchase of the farm
In May last little moro than year ago, he
commenced the work of opening the mine,
which Is now in full operation.
Gen. Gilmore, fully convinced of the value
of his find" worked systematically to de-
vcop the mine. The expense has been great,
but his trust has been fully justified, and he
has developed new industry in Maryland
and new source Of wealth for that state, as
we'll as now business for Washington which
is the national center of this mica trade.
He has demonstrated by examination that
there is strip of land extending many miles
in the state, about two miles wide, which has
valuable mica mines throughout its whole
extent, which in the near future will be de-
yeloped and add immensely tQ the wealth of
the country.
Very few persons understand the value of
and its scarcity. In fact, there has been lit
found on this continent, except in North
Carolina, valuable on account of It's size,
anterior to the discoveries made in Maryland
by Gen. Gilmore. There have been mines
opened in New Jersey, New Hampshire, and
Canada, but the output has been of size that
would not cut into large plates, and is not
therefore so valuable. The mines in North
Carolina produce very valuable ore.
Mica was first dscoveted and used in
Siberia. The name is derived from the same
root with 'mico," to glitter. II is q compost
tion Of silicate of alumnia, with small propor-
tions of sllcate of potash soda. lithica oxide
of iron, oxide of manganese, and little
fuorine 1t is found in mica slate and Other
azOic or primary formations. It's in blocks
of various sizes and thickness, the size into
which 1t can be squared governing the price.
The smallest square of any commercial
value is II by 81 inches which Is worth
forty cents per pound, the price increasing as
size increases, until piece by is worth
$40 per pound. The principal use of mica
plates is in stoves and lanterns, it being in
combustible and capable of being divided to
such thinness that the cost is even less than
glass Tho tough, flexible lamine which
form the block havo been divided into the
the thirty thousandth part of an inch OF
course mono so thin as this is used for COM
morcial purposes. "a process has been discov-
cred by which the mica plate can be silver
plated, and this makes it valuable in art.
The demand for the plates cannot be met,
and is daily increasing, there being seventeen
stove factories in Troy, N. Y, alone which
consume immense quantities.
New uses are also being found for the re-
fuse-that Is, the portions cut oil in squaring
the plates.
These are ground up and used as a lubri-
cant placed in the packing of safes and
boxes to make them fire-proof; mixed with
fire clay and used to line furnaces; put in
tar roofing used in the manufacture Of hard
rubber; in fine paints; by upholsterers for
putting on wall paper, and in various other
ways.
But to return to our Maryland mine. A
pleasant drive over tho Coleville pike to the
residence of Mr.. Beall takes us within two
miles Of the place, which Is reached over an
excellent country road.
The mine is situated ON the northeast brow
of hill rising about three hundred feet
above tho northwest fork Of the Potomac,
flowing at its base
Entering q large frame building, we find
an immense shaft seventy feet deep, which
we can descend either in buckets let down
by windlass or by an upright ladder fixed to a
wall. The water is removed from this shaft
by an immense siphon.
This shaft passess through three veins of
mica, one being twelve feet below the surface
at the shaft, another twenty-five feet, and the
third sixty five feet. These two last veins
have been reached by tunnels in the hill side,
the top one being worked from the surface.
In all these veins workmen are busily en-
gagged in taking out the glittering ore, which
is then conveyed about two hundred yards to
the large two-story frame shop, where there
is now at least fifty tons collected, the guam
tity being added to daily.
In the shop are other workmen and work.
women, whose business is to prepare the crude
article for the market.
1t is first taken out in irregular FORM
probably fifteen inches by eight and four to
six inches thick, and split with strong
knife into thicknesses of not over an eighth
of an inch. These are examined TO sec if
there are any cracks running through, and if
any are found the piece is broken of at the
crack.
These pieces thus prepared are passed to the
shearer, who with powerful shears fastened
to bench cuts them into the largest squares
and oblongs that can be obtained. From
here they pass to the cleaners and splitters,
who, with a knife which resembles drug
glst's spatula, clean of all foreign matter and
separate tho lamin@ until the pieces are
about as thick as ordinary glass.
This operation discloses in many instances
fractures, which renders new cutting and
reduction of the size in some of the plates
Great care is taken to cut mono smaller than
is absolutely necessary, as tho smaller the
pieces the less its value.
The thin plates in the hands of the cleaners
arc readily cut with ordinary scissors, and
this work of splitting and cutting is best done
by women.
The mica plates are then assorted, put in
pound packages, securely wrapped in paper,
the size marked on the package, placed in
boxes, and are ready for shipment,
The refuse aud the pieces too small for cut
ting are put into mill, ground to powder,
and put in barrels.
For want of sufficient accommodations at
the mine Gen. Gilmore is having great deal
of splitting and cutting done in the city, the
square blocks being hauled here for that pur-
pose.
Before reaching the mine the passer secs
the roadway glittering in the sunlight, re-
flected from myriads of particles of mica,
which is disseminated through the surface
soil for width of two miles ON each side of
where the vein is found hidden in the earth.
Gen. Gilmore has done a good work in dis
closing a new source Of wealth for the capi-
talist, and new field of labor for the work.
ingmen.
e
silver Purchase.
The Treasury department yesterday pur-
chased 365,000 ounces of fine silver for the
United States mints at Philadelphia, New Or