Audubon Republican. [volume] (Audubon, Iowa) 1894-1925, 1896-01-23
TESTING THE oREs.
1sw Samples from the Diggings Are Pre-
pared for the Assay once.

sss. ~st.Ss
H~w Samples from tho Diggings Are Pre-
pared for tho Assay once.
To the uninitiated but observant
stranger who wanders up and down in
the labyrinth of shafts and tunnels
diggings and dumps of genuine min.
Ing camp perhaps there is no subject
more full of interest than the proceA
by which lump of brown ore, which,
to his inexperienced eye, looks not in
the least attractive, is made to Weld
Its share of silver and gold, or the
means and methods by which the min
Ing man at his side 30 confidently as
sures him that ton of that ore will
go 1888 ounces in silver and $17.55 in
gold. Even the eastern mining expert
or graduate from some mining school
will wonder how, in the log cabin or
pine shanty, destitute of all the elab-
crate paraphernalia to which he has
been accustomed, these results are so
readily and accurately obtained.
AS a general rule the majority of the
ores, except those containing the pre-
cious metals, for purposes of purchase
s~A1N osaAS civ NuiuCu ACCOUNTING 10 U16
cost of mining and shipping, SO that, ex-
cept for metallurgical purposes, it is un-
necessary to seek to determine with
much accuracy the contents and vslue
OF such ores. In case of ores rich in
the precious metals, however. it is en-
tirely different, as in their purchase
and sale both parties, the buyer as well
IN fns
curately and to a certainty the value
of the entire lot. The methods by
which this knowledge is obtained are
80 simple as to be easily understood
and practiced by many man who does
not know the technical symbols of the
metals he is determining or could not
give scientific exposition of the proc
ess, but, nevertheless, in his line, he
is an accurate and Successful assayer.
When a quantity of ore is to be sam
pied for assaying it is first broken by
an ordinary rock crusher into pieces
the size of an English walnut, after
which it is shoveled back into the car,
but in such a manner that every fifth
shovelful is thrown aside by itself, the
remaining four-ffths being finally
taken away This fifth portion, known
as the sample" is then reduced to
much greater degree of fineness by
means of Cornish rolls. 1t is then piled
on the floor in a cone, fattened out, and
divided into four equal portions, and
woopposite quarters are then removed.
The remaining quarters lire again
thoroughly mixed and again piled in
a cone, f1attened and quartered; this
operation being repeated until the sam
pie is reduced to 100 pounds. 1t is then
weighed repeatedly for the purpose Of
determining the amount Of moisture
contained in the ore, which in some
ores, especially those of the concen-
trates, is so considerable as to make
very appreciate difference in the
weight. The moisture is then expelled
and the orc is crushed to such degree
OF fneness that it can be passed through
a sieve containing 100 holes to the linear
inch. The sample is next put up in
small bottles, which are scaled with
sealing wax and then stamped for the
purpose of preventing the possibility
of their being opened or tempered with
without detection.
The above is the process of sampling
used among the mines, and the SAM
pie is now ready to be assayed, but
only small portion CT it will be used
for that purpose, and the quantity gen.
orally taken is what is known as an
"assay ton," which weighs %, 166 MILL
grams, or a little more than $50 grains
troy weight. This definite amount is
taken, partly as a matter of conven-
hence, and also because the assayer
wishes to ascertain, as quickly as posi-
BILE, how many ounces of the precious
metals to the ton are contained in this
ore. The method used depends upon
the following principles: The avoirdu-
pois grams ton of 1000 pounds contains
29,166 ounces troy weight; hence, when
20, 166 milligrams of the unassayed ore
are taken, the weight of the resulting
button" of gold or silver in the milf
grams represents at once, without any
further calculation, the number of troy
ounces of gold or silver in the avoirdu-
pois ton of the ore.
This method was invented in the
Columbia School of Mines in New York
city and is in general use throughout
the world wherever there is assaying to
be done.-Boston Transcript.
The Care of the Feet.
"There is no necessity whatever for
so much complaint of the feet if people
could only be induced towear the prop
er kind of shoes, said surgeon who
has made the foot the subject of special
study. "The great mistake that is