El Paso herald. (El Paso, Tex.) 1901-1931, 1910-08-03
Deposit Is Rich and Many
Demands Are Made For
the Big Output.

The state of Sonora, Mexico. has the
! distinction of containing the only
| graphite mine in that republic, and
one Of the most valuable in the world
Graphite. also called piumbago and
black lead. is = mineral found in many
. parts of the world, but seldom in pay
ing quantity or quality. 1t comes from
Mexico. Ceylon, Europe and Asia, and
! frequently throughout the United
States and Canada. The greatest
quantity comes from the Sonora mines.
There are two formations of graph
! ite-the crystalline or flake, and
amorphous or nOnstructural- The
| amorphous is the more valuable be-
cause 1t is susceptible to reduction to
! impalpable and gritless hneness and is
of a nature to combine readily and /
! intimately with other matcrials-lA 4,
pencil making with clay. in grease
making with oil. in paint grinding
| with the vehicle. The crystalline OF
! flake variety is unsuitable for these
/ purposes.
The Sonora mine yields the amor
| phous. or desirable variety Of the very
! hest quality. and is used in prepare !
zion of graphite for pencil making, !
| powder glazing electrotyping, toun-
| dry facing. graphite neint, graphite /
! lubricants and stove polish
Owned by Michigan Company.
The Santa Maria deposits. owned
and operated by the United States
Graphite company, OF Saglna"
Mich. are located on the Santa Maria
ranch. 20 miles south of the mining
| town of La Colorado, and about o"
| miles north Of Guaymas, Sonora. Mex
! leo According to a report OF Frank L.
! Hess, Of the United States geological
| survey. this is the greatest producer
| Of graphite on this continent The de-
| Dostts were discovered in 1867 and
! work began in 1891, though CONNER
| cial operation did not commence III
| 1895, since which time the Saginaw
| company has steadily pushed opera
| rions. Near the graphite mines the
rock changes from volcanic To sedi-
| mentaries. sandstones around the mine
/ and a little to the southwest heavy
! limestones.
Many Beds Found.
A number of beds of graphite occur
| at least seven. Only one is exposed IN
| the west shaft, but in the north smart
! six beds have been cut Around ooIh
shafts everything is covered with
! metallic Iuster in the bright sunlight
|
| faces take on the same metallic sheen
The graphite bed, as at present
| mined. reaches from nine to ten feet
! in thickness. and is extremely irregu-
lar in strike sharp curves coming
| closely together. Owing to folding, the
vein squeczes and swells. One lentcu-
lar mass reached a thickness of ~
feet with breadth of 10 feet YER,
ticaIIy and $50 feet horizontally On
the sixth level vertical depth of lo2
feet, a mass nine feet was being
stDped It had been mined from the
seventh level almost TO the fifth and
had a width of perhaps 80 feet. The
wall rocks are generally sandstone.
Can be Crushed With Hand.
The graphite has the familiar sub
metallic. grayish black luster which is
UNIQUE and so characteristic that 1t
can be described only as graphite.
Most of it is in small lenticles which
are from an inch to seven inches long
and are easily broken into smaller
pieces. Some fragments show dis
| tinct paraIlel structure similar to coal.
The graphite is so soft and friable
that a large lump may be taken in the
hand and crushed TO small particles
I II is velvety. soft and smooth 10 the
touch. 1t is formed from coal that has
! been altered by volcanic heat
! Almost no explosions are neeueu III
the mines On account OF the friabiIlty
of the bed, most of the mining being
done by pick and shovel
Analysis shows Rich Deposits.
The ANALYSIS of run of mine graphite
is as follows:
Carbon. all graphite, 1913 percent.
Silica, $50 percent.
Iron. 60 percent
| Alumina 800 percent
The purest samples show 80 percent
| praDhitic carbon. It is wholly amor
| ! nbous and shows no flakes like that
| mined in Pennsylvania, New YORK ana
! Canada. and no fibrous structure ike
that of Ceylon-
After being raised to the surface the
graphite is spread out in the hot sun
{ to dry and then thrown UP in piles ior
shipment. 1t is hauled by mule teams
TO La Colorado station and then shipped
TO Saginaw, Mich, for treatment
where it is ground and separated by
means of air fiotatiOn and boiling
Some of the best pencils in the world
such as the Koh-i-noor, made Dy
Hardimuths. in Austria. and nearly all
of the better American pencils, are
made of the Sonora graphite 1t IS also
used TO coat gunpowder- The larger
1 use is for lubricating paint, foundry
facing and stove polish. 1t is worth
from to 10 cents a pound in the
, market.