Custer weekly chronicle. [volume] (Custer City, S.D.) 1890-1931, 1899-04-29

| tney yleld tnelr goid readlly 10 chlorl
nation, cyanide, or bromination. Blu
the best process thus far for us which
has been tried, is chlorination, and tha
too without roasting. There may b,
some men so skilled in the smeltin,
business that they can save the value,
in smelter, but it has cost us some
thing to find out that there are a good
many smelters that can't do it, Our
advice to those who contemplate in
vesting in Custer county mines is, dont
be afraid of spending little money in
making tests. Not alone by the com
mon fire assay. for that is no good when
it comes to telluride gold ore. We have
found that about as profitable as hiring
man to cut wood with a stone ham.
mer. What you want is to find out the
amount OF gold your rock contains, and
you never will know anything about IL
if you depend upon the common fire
assay. But if you can induce your as
sayer for love or money to lay aside his
Sobhioh hiCthuu VI utc assay lOI thc
time being and try the following for
mula, he will very quickly see the differ
ence.
First pulverize your ore and put pulp
in an earthen vessel and subject it to a
sand bath with moderate heat for
twelve hours while covered with
dilute nitric acid. When dry put
in scorrifier with test lead and litharge
20 to l. Cover heavy with plenty borax
and heat up in furnace very slowly for
time, and then increase heat to pei
feet fusion, but have care that it does
not get too hot. Your button may need
repeated scorrification but always with
plenty OF lead at least 20 to ].
If you can get your assayer to do this
carefully and faithfully (pretty hard
thing to do) you will have the satisfac-
tion Of knowing that the ore has been
put to fair test, and you will get high
percentage Of the gold contained in your
ore. The trouble with the common fire
assay is that the tellurium passes off in
the fumes at such a low heat, and the
gold and tellurium being in combina-
ton, the gold passes off with it by vola-
tilization. In this manner the gold
escapes as an invisible gas, which is of
course unseen by the assayer, who, if
he gets good fusion and a good pore,
he is ready to go into court and swear
he has obtained all the gold contained
in the ore. Such ores are very decep-
tive, and we have known reputable as
saycrs to return a certificate showing
only a trace Of gold when, as a matter of
fact, the very pulp they were treating
when tested chemically went $l4209 in
gold per ton, and when treated by the
formula we have given went $l2l.O0 per
ton.
The loss of the precious metal by the
common fire assay is not alone by vola-
tilization, although therein lies the
greatest danger of loss. But the loss by
absorption in the cruicible is great, and
this, in addition to what is lost in the
Stag, makes the common fire assay en-
tirely unreliable on this particular char
acter of ore. The acid bath changes the
character of the ore to a great extent,
oxidizing the base material to degree,
while the excess Of lead envelopes and
combines with the gold and silver so
readily that there is not much chance
for the values to escape. Ofcourse there
is test far superior to this, but it is so
expensive that but few of the ordinary
prospectors and miners can afford to
take advantage Of it. l refer now to a
thorough chemical analysis, which after
all is the court of last resort, and which
decision We must accept as final.