Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1868-11-25
G0W SILVER ORE IS WORKED
MYSTERIES OF THE PROCESS.

LIE NeVada correspondent CT the Tin
clnnati Commercial gives tie following in
terestins description of silver manufac-
ture:
The reduction Of silver ore is q heavy
manufacturing business, requiring extern
sive and complicated machinery and appli-
ances, and rather more than tic usual pro
portion Of skilled labor Step with me. if
you care to see an iliustratiou, into the
new and complete mill Of a company at
this place and watch the ore turn, in due
process, to bars of kullion.
Outside is small hill OF ore transported
BY wagon, at cost of from four to six
dollars ton, from tie mines ten miles dis
tant. The ore S simply hard quarsz, in
tiltrated with various metals Unless the
ore is very rich you can seldom discover,
even by the aid of glass, any Of the
minute particles of silver. Some ore looks
like gray limestone The Pahranagat ore
igalmost prismatic, being spotted yellow by
decom posed lead, blue by copper, brownisil
red by iron, and dark lead color or black
by silver. The ore is carried in ox-hide
baskets to the crushing room, where it is
weighed and registered. Then it poured
out in the stamp room, where man with
a long handled shovel feeds it under the
stamps.
TIE ten stamps are simply upright iron
hammers, weighing six hundred and fifty
pounds eaeh Their province is to crush
the ore into dust as fine flour. The
dust can not escape from the stamps until
it flies through selves in powder SO mi
mute as to be almost impalpabIe to the
touch. A ton of ore can be sufficiently
crushed in two and one-third hours.
The next step is to roast your fne pow
der Cor pulp, as it is called) in order to
burn up all the base metals in it except
silver, gold and copper. The "rasters''
are ordinary ovens, like those used for
baking bread, except that the fues are
admitted to the chamber where the pull
verified ore is deposited. Workmen called
'roasters," also stir the dust with long
handled shovels, keeping up cherry red
heat. Each of the FIVE furnaces has ca
pacity for half ton of dust, and the time
consumed in roasting the pulp is six hours.
Your dust, when thoroughly roasted, con-
tains nothing but gold, silver and copper
in powdered quartz. The other metals
have been effected by fire and large guam
titles Of salt thrownin to chlorodize them.
The roasted dust is raked out on the o.
posite side of the furnace and conveyed
into the amalgamating pan, or large tubs
filled with hot water, where it is further
ground in a sort of iron fan wheel, and
where FIVE pounds of quicksilver are
thrown IN for every pound of silver you
estimate your ore to contain. Quicksilver
will take up one-ffth of its own weight of
precious metals The union made, the
alnalgam of the two metals sink to the
bottom of the tub, and the quartz pow
der runs of in amuddy ri!l from an orifce
above.
Next the amalsam is taken from the
bottom Of the tubs aud strained through
canvas bags, in order to get rid Of any SUI
perfuous quicksilver. The amalgam,
after this staining, IS five parts quicksil-
yer, and one part silver. 1t looks and
feels like silvery sort of wet, white sand.
The amalgam is now ready for the ANAL
gamator, the most important artisan
about the mill, and the one who generally
has charge of both mill and workmen.
lie places the amalgam in furnace of his
own, and builds a fire hot enough to send
the quicksilver off in vapor, leaving a
re8iduum of silver. The flying vapor is
condensed in water and returned to its
original form of quicksilye., ready to be
used again, having lost but one per cent
of its bulk The silver left in the retort
looks like rusty chips dragged metal and
IS anything but precious in appearance
The process of casting the silver bar
usual we ght about eighty-fve pounds) is
simple enough. The silver chips are
placed in black lead mould, melted, and
come out a bar of silver, or rather bar
about 800 parts silver and 200 parts cop
per. Such is the bullion, of commerce,
and such a bar is worth from 81 200 to
$1,000 in coin. The copper is taken out
Ia the minis in such manner as to save IT..
A good silver mill, with its branch
buildings covers two acres, and is crowded
in all parts with machinery. The milling
process, at best, does not save over eighty
tive per cent Of the silver ore. The other
fifteen per cent, is sensibly lost in the va
nous stages of reduction. A ten-stamp
mill burns twelve cords of wood per day,
and consumes l, 900 pounds of salt. Other
supplies and labor run up its daily expen-
ses to $500. If it has 500 ore, its re-
ceipts are Sl00. But 500 ore is high
grade, and not very abundant in any
mines ii Nevada, SO far as they have been.
penetrated by the pick.