San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1893-07-05


pal varieties are white silver,which
is the rarest and best; green sill
Yer, which is united with copper;
bronze, which is united with iron
red, which is united with lead, and
is very soft ore; chalk, which
greatly resembles the common
white lime stone, but which is rich
in silver and easily worked.
SAMPLING ORES.
Very few persons have any con-
ception of the process by which the
value of ore is aScertained, and yet
the miners and the purchasers can,
at very little expense, ascertain the
value of ton of ore to the fraction
of a dollar. There are two modes
of sampling ores. The first one is
this:
The miners get out lot of ore,
throw it on the dump, or on
board the cars, and weigh it. From
a ton of this ore they take out
shovelfuls from every part of the
pile or lot, until they get one hun
dred pounds from the ton. That
is taken to the crusher and
pulveriZed. 1t is their spread out
on a plank or a cement floor, and
mixed up; it is piled up in the
form of a cone, and worked down
level again in about the same way
as a mason would mix up morter
until they are thoroughly incor-
porated into each other. After
this is done the ore is again leveled
off smooth. 1t is then divided in
to four quarters or equal parts.
No. | and are taken out and put
in a pile together, while two and
four are put in another pile. The
first pile Is then mixed the same
as it at first, deferred again the
same way, land again mixed and
divided from six to ten times, I'M
til the original pile is reduced to
four pounds.
This ore is then put through
rollers and reduced to fine pow
der, when the process of coming
is again gone through, and divided
into four parts. These are put in
to separate vessels and introduced
into an oven, being left there eX-
posed to a high degree Of heat,
until every particle of moisture
has been expelled. When cool
the samples are separately put on
smooth table and thoroughly
mixed coned, leveled, quartered for
the last time, and half of
each sample is passed through
sieve which has 100 meshes to the
inch. That which adheres to the
silver or will not pass through is
emptied upon a chilled steel plate
and hammer until it is reduced to
a powder so that it will pass
through the seive. This is gain
mixed, and then put up in small
sacks and sent to the assayers.
Each one of these sacks are sup
posed to contain an accurate
average of the contents of the
original car load, or dump that the
ore was taken from. If that
sampling is not satisfactory, then
sample , and t of the original
sample are put through the same
process and if the work is carefully
done there will be but trifiing
variation in the assays of all the
packages. The difference would
be so small that it would not
amount to twenty-five cents in the
ton of ore.
FINDING THE VALUE.
To find the exact value is the
most difficult work of all.
The assayer picks up one of the
sacks at random and weighs the
contents on a pair of scales that
are so delicate that the smallest
mark that can be made on a piece
of paper with a lead pencil will
disturb the. balance. The assayer
carefully notes the weight even to
the fraction of a grain.
After weighing the sample he
places it in a furnace for the
purpose of Kidding the ore of sui.
phur, which greatly interferes with
smelling. The furnace is heated
up to point short of fusing, and
requires careful watching. This
will take about two hours.
After the sulphur is expelled, he
places the sample in a cupel, g
small vessel about two inches il
diameter which is made of bone
ash. When it appears that there
is any considerable amount of leaC
in the ore the sample is placed il
the cupel without the addition o
any other substance; but if tn,
quantity of lead be small he wraps
the sample in piece of lead fol
which was first carefully weighed
this bpino necessary tO Socur,