The Logan Republican. [volume] (Logan, Utah) 1902-1924, 1906-08-11

The losses occurring during fusion
may be very great. In some instances
experiments have shown loss OF gold
varying from three per cent to twenty
per cent, and Of silver varying from
seven per cent TO thirty per cent. The
fusion TO be as nearly accurate as pos
side is best performed in a muffle fur.
mace. where the heat Is even and at
all times under the control OF the
operator. Fusion must take place in
all parts II the crucible simultaneously
as this is obviously an impossibility in
the gasoline furnace. Too great a
starting heat causes violent ebullition
OF the melting charge. and values are
thrown out OF the crucible and in case
OF rich samples being next TO low
grade fusioDs, there is great danger OF
sailing.
A transfereDce OF values from one
crucible TO another may be accom-
plished with the tongs used in placing
the charges into the furnace. The
finishing heat OF fusion is also a
very important point, or the values
retained In the Stag will be enormous.
The writer has experimental with
highly silicious gold and silver ores
and found that the Stag retained from
| IL to per cent OF the gold and as high
as Il per cent Of the silver values.
This was corrected by using a more
fluid Stag and higher finishing tenn.
perature.
In removing the Stag from the lead
buttons careful attention will detect
imperfect fusion or poor nuxing, and
such lead buttons should be discarded
and the assay re-run or the losses will
be large during the cupellation, which
is the most delicate part Of the assay.
The losses during cupellation are
caused by too great degree Of heat
during the operation, poor cupels or
fuel lead buttons. Many assayers
claim that heat does hot affect gold
True, gold does not volatile itself at a
possible assay furnace heat, but the
too rapid volatilization of the lead will
carry of some gold values and large
amount of silver. The intense heat
also assists the impurities in the lead
button TO carry the gold and silver in
to the cupel.
From experiments performed by Fu-
man, Collie, Wood, Kirk, Ross. the au.
thor, and several others, IL has been |
found that the materials used in and |
the construction OF the cupel has a
great influence over the results. The
blue-ash should be OF the very best
grade and each cupel carefully made
and tested or the utmost care in Gu
polling will show loss OF from to 30 |
per cent Of the values
Even with the best cupels some OF |
the common elements OF ores largely |
affect the results unless they are |
thoroughly removed before passing the |
button to the cupel.
OF these tellurium is probably the
most disconcerting to the inexperi- |
enced man. as the losses will at times |
reach as high as 100 per cent on very
rich ore. Bismuuh is the next hardest
element with which to deal, as IL has
a very large capacity for carrying gold |
and silver values into the cupel Ex- |
periments have shown a loss as high |
as p per cent OF the gold and 34.4 per
cent loss OF the silver. Arsenic, anti !
mHny, copper, zinc and sulphur, all |
have tendency toward lowering the |
results. Even proof gold with chem
ically pure lead may show big loss |
during cupelling in combination fur
mace at the same time he is running |
melts In the crucible chamber, as |
either one operation or the other must
be sighted. In looking for a man to |
do your work first look for the compe-
tent, conscientious assayer who knows
how and is not mere machine treat
ing all ores alike. BE certain that he
will give your sample the same careful
attention he gives TO those of his
best customers.
See that your assayer has proper ap-
planes and is careful in the bucking
room-that he has furnance capable
OF doing the best work: that his BALI
ances are such as to give accurate re-
suits. There are in every camp sever
al good men with good appliances, and
II you are spending your money and
expecting good results, these are the
men you should patronize.