Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1913-02-25
HOW YELLOW METAL IS BOUGHT
Uncle Sam Takes All the Gold BROUGHT
To His Mints or Assay Office.

| To His Mints or Assay Office.
Suppose that you owned a gold mine
What would you do with the gold? II
the ordinary commercial lines the mar
keting Of the product depends upo,
ability to place 1t before the people
and involves the meeting Of competi
ton, adjustment Of freight rates ant
the surmounting of numerous littl,
difficulties. all Of which have a bear.
ing upon the ultimate result of you,
undertaking. With gold It is differ.
ent. Uncle Sam stands ready to buy
al OF the gold brought to his mints o,
assay offices.
There are three coinage mints where
you would be able to dispose of YOU,
bullion, VIZ, Philadelphia, Denver and
San Francisco. Should 1t happen that
your mine was not located convenient
to any Of these mints you would find
United States assay offices at Boise
Idaho; Carson, New; Charlotte, N. c.;
Deadwood, g. D.; Helena, Mont; New
Orleans, La; New York City; Salt
Lake, Utah, and Seattle, Wash. AT
these institutions gold bullion Is pur-
chased and forwarded to the mints.
You would take your gold into the
office and watch II weighed upon a
pair OF balances so sensitive that al
though they had several hundred
pounds in each pan one one -hundredth
of an ounce would be indicated. Hav-
Ing weighed your gold, the officials
would issue a receipt for It, which you
would keep until you received your
check or coin in payment. Your gold
would then have become what is
known in the Office as a deposit" This
deposit, with many others like It,
would be turned over to the melting
department, where, in q specially
constructed furnace, It would be melt
ed In plumbago crucible with the
proper fluxes and poured into q suit
able mold. Simple as this may sound,
the melting Of gold is a very serious
and difficult task. The high heat which
1t is necessary to generate in order to
melt the metal, necessitates a furnace
constructed Of the most refractory ma
terial. These furnaces are usually op-
Grated by gas or oil and are built of the
very finest grade Of fire brick and fire
clay. The plumbago crucible which Is
used Is composed Of graphite (the
same material that comprises the CEN
ter Of your lead penciD, q little fire
clay and little sand. In the manu-
facture of these crucibles, great care
must be taken to secure a uniform
mixture Of the component parts. 30
that when heated no portion Of the
vessel vii expand more than any other
portion. Unequal expansion would
cause cracking.
The crucibles are fashioned in molds
and dried, or burned in kilns. after a
fashion similar to dishes or bricks.
They are made in all sizes from those
having the capacity Of an after dinner
coffee cup to immense sizes holding
over twelve gallons. Before melting
gold In one Of these crucibles It Is ne
cessary that 1t be very carefully an
nealed, which means that the last pos
sible traces of moisture must be ex-
PEELED by slowly Increasing the tenn
perature for several days. This is done
by placing the crucibles In a steam
heated oven, where the process is car
ried forward until 1t Is deemed that
the vessel is in suitable shape to be
placed in the fire. Covers and stirrers
are made of the same material as the
crucible. The latter are used to stir
the gold in the crucible after 1t Is
melted. Covers and stirrers pass
through the same annealing process as
the crucibles, although it is not neces-
sary to take 80 much care with them.
Gold coming direct from a mine is
never pure. 1t may contain various
base metals, the nature Of which de-
pends upon the process by which the
gold was won from its matrix. Gold
from stamp mills contains some iron
very likely some copper and often
some quick silver. From cyanide mills
the bullion nearly always contains
zinc, as this metal Is made use Of In
the process. The zinc, too, may also
have contained impurities, some OF
which will very likely be in the result
ing bullion. Copper has. some OF the
characteristics Of gold, both physical
and chemical, as that If copper Is con-
| tanned in the original ore some OF II
| will be very likely contained in the bull
lion. Silver Is always associated with
gold in the ores Of the latter. The
amounts may vary greatly, but 1t may
be stated that silver is always present
in gold ores.
The problem Of the melter who
handles the deposits at the assay office
is to make from the deposit bar OF
bullion which will be homogeneous, or
in other words, a perfect mixture from
top to bottom and from end to end OF
the gold and other metals. In order to
90 lIllS lie pldCco III tiS SieSAe'S "-~-
the deposit a stated amount OF f1ux
varying with the size and composition
Of the deposit. The virtue Of this fux
is to remove a certain portion OF the
base metals and likewise to form
molten mass over the top of the bull
lion which will prevent volatilization
of the precious metals. 1t Is lighter IN
specific gravity than the metal and
rises to the surface Of the melt. For
clean bullion the f1ux Is composed usu-
ally of borax. Perhaps some little
soda will be added. For bars which
contain FIVE or ten per cent or more
of the base metals the flux will be
comprised more largely Of soda. This
Is just the ordinary soda which the
housewise uses in collaboration with
sour milk to make biscuits or other
dainties. Niter is also used on bars
containing large amounts Of impuri-
ties.
Having placed the deposit In Its
crucib.e in the furnace, with the ne
cessary fiuxes, the heat Is applied and
the metal and fux melted in thirty to