Tonopah bonanza. [volume] (Butler City [i.e. Butler], Nev.) 1901-1909, 1904-09-03
TON0PAH BONANZA.
SEPTEMBER 3, 1904
sAMPLING ORE SHIPMENTS.
How Tests Are Made by Owner
of Mine--It is Very Simple.

cepted as automatic by some, that
custom works, whether smelter,
c~hlorination or amalgamating, are
often unfair, even though owned and
managed by men of the highest in
tegrity and technical skill. This slur
is constantly thrown at them. be-
cause, forsooth, the ore shippers do
not get the returns expected accord
ing to their W sampling and assay
ing.
Why these discrepancies occur, is
the object of this article, being
brought home to the writer very late
ly when a dispute came to his knowl-
edge, due, as far as can be learned
by correspondence, to errors 10 samp-
ling on both sides, but mainly to the
faulty method pursued at the mine.
After years of experimenting by
competent metallurgists, in all parts
of the world and on all classes Of ore,
one method was devised which gave
as nearly accurate a sample Of the
ore tested as it was commercially
possible to obtain, and this has been
now universally adopted by all sam
ping works, even those under the
ownership and control of the mine
owners themselves. Unless a similar
procedure is carried out at the mine,
the resultant values will not tally ex-
cept by accident or when the ship
ment is absolutely uniform in size Of
rock as well as in the distribution of
its valuable contents. However, il
is very probable that with regular
shipments, weekly or even more fire.
quently, the errors OF values would
balance themselves in the course Of
time-perhaps 10 six months, perhaps
in a year-but il the market price of
the metal was fiu~ctuating. each indi
yidual lot must stand on its own val
nation.
1t is not a good thing to cheat
oneself, and yet this is what many
miners do, partly due to human ma
ture, but mainly TO negligence. I'm
portant shipments are mad and the
values determined by the assays OF
grab samples, and it is human nature
to pick out, perhaps uncousciously,
WV btANNt AAdAE VI tbfh anu AMY
clean ore, and not the fines which
probably are much poorer or much
richer, from the waste which must
get into the bulk il worked on a com.
mercial scale. Or a grab sample is
taken from the top Of each sack Of
concentrates, which are usually damp
when put into canvas bags, and al.
ways unequally mixed, the finer and
generally richer sulphurets collecting
on the top in settling the mineral by
jumping the sack. Perhaps a little
more physical exertion aud supposed
carefuluess is employed. The ore is
OF all sizes from ten pounds weight TO
dust, and each days product is
dumped together, from which an oc-
casional shovelful is thrown on the
sample pile while filling the sacks.
At the end OF the day this is taken ia
the assay Office and found of sufficient
value TO ship. The same operation
is repeated each day, aud at the end
of a week sufficient has accumulated
for a carload and is sent away; but a
different weight was sacked each day,
and there have been appreciable dif.
~ferences IN the daily assays. Yet
the shipment is valued on the aver.
age Of the assays and perhaps also
checked % by the assay Of all these
samples mixed together. With such
absurdity, can there be expected any
agreement between mine and reduc.
ton works2 Perhaps only concen.
trates are shipped, but the ore has
come from all parts of the mine, and
there is a daily difference in the
values of the sulphurets, depending
OF whether the bulk Of that days
output came from the oxidized ore Of
the upper levels or the sulphides oI
the lower levels, whether, also, taken
from the pay shoot or outside Of it.
Then occasionally the settling boxes
are cleaned out and mixed with the
concentrates Of that days u OF the
mill. These concentrates are dried
and sacked each day and graded &C
cording to the assays into different
lots; but even in each lot there il
often a variation OF values between
the contents Of the sacks Of ounces
Of silver and dollars of gold. Can 9
true estimate be made by averaging
these different assays, or ~assayinl
the mixture of all the samples, will
the variations Of weights Of eacl
days run as well as the difference
in valued 1t is an absurdity. and yet
all of these methods are employed
and by men known to the writer az
intelligent, good practical miners
and superintendent, with otheI
methods just as ridiculous.
Twelve years ago the writer wa