The Wichita daily eagle. [volume] (Wichita, Kan.) 1890-1906, 1896-01-15
TESTING THE ORES.
Hov Samples from the DigginGs Are Pro-
pared for the Assay once.


To the uninitiated but observant
stranger who wanders up and down in
the labvrinth of shafts and tunnels,
diggings and dumps of a genuine min
ing camp perhaps there is no subject
more full of interest than the process
by which lump of brown ore, which,
to his inexperienced eye, looks not in
the least attractive, is made to yield
its share of silver and gold, or the
means and methods by which the min
ing man at his side so confidently as
sures him that ton of that ore Will
go S2.33 ounces in silver and S17.55 in
gold. Even the eastern mining expert
or graduate from some mining schoo!
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
and sale are valued according TO tho
cost of mining and shipping, so that, ex-
cept for metallurgical purposes, it is IN
necessary to seek to determine with
much accuracy the contents and value
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
as the seller, want to ascertain &C
curately and to a certainty the value
of the entire Let. The methods by
which this knowledge is obtained are
so 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 a 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 a
much greater degree of fneness by
means of Cornish rolls. It is then piled
On the floor in cone, flattened out, and
divided into four equal portions, and
two opposite quarters are then removed.
The remaining quarters dre again
thoroughly mixed and again piled in
a cone, fattened 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
q very appreciable difference in the
weight The moisture is then expelled
and the ore is crushed to such degree
of ineness that it can be passed through
a sieve containing 100 holes 10 the linear
inch The sample is next put UP in
small bottles, which are scnled 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 samplins
used among the mines, and the sam
pie is now ready 10 be assayed, but
only a small portion Of IL viii be used
for that purpose, and the quantity gen
orally taken is what is known as an
ASSAY ton" which weighs JOG MILL
grams. or little more than $50 grains
troy weight This definite amount is
taken, partly as a matter of conven- |
fence, and also because the assayer
wishes TO ascertain. as quickly as posi- |
bic, how many ounces of the precious |
metals 70 the ton are contained in this |
ore. The method used depends upon |
the following principle: The avoirdu-
pois grams ton Of 2,0G0 pounds contains !
29.165 ounces troy weight; hence. When |
%. 166 milligTams Of the unassayed ore |
are taken. the weight OF the resulting /
button" OF gold or silver in the milli- /
grams represents at once, without any |
further calculation. the number Of troy 1
ounces OF gold OF silver IN the svotrdu-
pois ton OF the ore.
This method was invented in the 4
Columbia School OF Mines IN New York 4
city and Is in general use throughout /
the world whereser there is assaying 20 4
be doae.-BostoD Transcript.
The Car, Of the Fec.