The Jeffersonian. [volume] (Stroudsburg, Pa.) 1853-1911, 1868-11-26
DeOotO poies etau Agriculture sriencc otp ouo c5encr
sTRoUDsBURG, MONROE COUNTY, PA, NOVEMBER IS, l8s8

a comes too deep for supplying pure a
] from the mouth, an air shaft is WORK,
: up perpendicularly to the surface, co
slant current Of air is thus secured, an
| the tunnel can then be driven for hu
dreds of feet again. The miners not Oh
ly dig the ore, but they select it carefull
from the granite. An experienced mine
Will distinguish quartz as soon us he get
his hands on it, and needs no particula
examination to determine its quality
He is familiar with the peculiarities Of th
lead he is working, and can tell at one
whether rock is granite, or first or Sc
cond class quartz. This requires consi
derabie practical experience. | have seer
gold quartz OF every conceivable color anC
formatlon-white crystal, cold gray, al
shades of blue, yellow and pink, ami ev
cry shade of darl; to jet black. Quart.
is usually very rich when gold can be de
tected in it with the naked eye. Miner.
understand what particular formation.
carry the gold, and they seldom err in
estimating its value In sulphurets the
iron will glisten with briliancy that
makes any inexperienced observer pro
nounce it gold ; but the gold is infused
in the iron in very fine PARTICLES, and sell
dom can be seen at all. Occasionally
nugget gold will be found in quartz, but
1t is only in rare specimens Of uncommon
richness that the gold appears in that
way. The average cost of mining ore in
Colorado [ would estimate at s. per tun.
In Montana it costs probably IS per tun,
but its development will be cheapened as
it is systematized.
When the ore is nIinel, it is delivered
to the mill either by wagons or railways,
where it is broken about as fac as stone
IS usually broken on good turnpike road
This is sometimes done by machine call
ed Cracker" but usually by hand, with
the common sledge. 1t is then ready for
crushing, aud the process in most general
use is the stamp mill. y mill consists of
from two to six batteries" each hattery
having fve stamps, which consist of hea-
Wy, round bars of iron, set perpendicular
ly, widening at the bottom, on which is
fitted steel shoe. Beneath the shoe is
steel die, firmly imbeddel, on which
the stamp drops. 1t is hoisted by each
revolution of the machinery to a certain
point, whirled partly around as it hoists,
and its force consists simply in the drop
of its weight upon the die Each battery
is surrounded with an iron frame or box,
into which tie Gre is thrown, and strong
stream Of water pocrs on it constantly
On the outer side Of the battery through
screen or sieve issues the water, aud
with it is carried the fine quarts as it is
pulvcrised, so that feeding goes On con-
stantly to supply the place of the fine
quartz as it escapes. In the bate
ry is placed a quantity Of quicksilver,
with which large proportion of the gold
amal gamates as the rock is crushed, and is
held there until the "clean up" Many
PARTICLES of the gold, however, escape
with the fac qugr;z through the screen
before it is brought in contact with the
mercury, and, in order to catch it, the
water and quarts from the latter are run
over copper plates, from two to four feet
wide, and ten to twenty in length, ANAL "a
mated with quicksilver. IF the plate is
properly coated, every particle Of free gold
will reach the bed of the plate iu passing
over it, aud safely lodge in the mercury,
but if the gold is impregnated with the
base metals, it will not amalgamate with
the mercury. 1t will pass over the plates
and sink in The boxes or ripples (such as
are used in gulch mining, and before des-
cribed, while the light earth aud sand
will wash away These mixtures Of gold
with the base metals are called sulphurets,
and they are worked successfully in Mon
tana thus far by arastras or barrels. An
arastra is simply carefully laid bed of
stone, about eight or ten feat in diameter,
encircled with wooden rim; an upright
shaft stands in the center, with two arms
extending out, to each Of which is attach
ed heavy rock with Il smooth under face.
1t is SO attached as to be raised "A little in
front, while the main weight of the rock
drags on the stone floor. Iuto this bed,
from 800 to 500 pounds or more of sui
phurets are thrown, quicksilver added,
and stream of water turned on to it. \
mule is hitched to the shaft on the floor
above, and he drags the head stones Il.
round over the sulphurcts until they are
pulverised into almost impalpable powder,
aud then they are panued out just as pros
pectOrs pan earth in gulches, or sluiced of
over anna! gamated plates. Some stamp
mills have metal pans in which their tail.
ings or sulphurets are worked on the prin
ciple of the arastra, and other mills have
wrought iron barrels about three feet in
diameter and five feet long, in which are
half dozen or more large metal balls
The sulphurets are Put in the barrels,
bout 800 pounds to each, aud the barrels
run about twenty revolutions per minute
The constant shifting of the tailngs and
rolling Of the balls, rapidly reduces the
base metals, and separate the gold, which
amalgamates with the mercury mixed with
it in the barrels These different process