Santa Fe new Mexican. [volume] (Santa Fe, N.M.) 1898-1951, 1903-05-13
Edison Process Of
Separating Gold
Authorized Description of the Experiments Which
Have Been Conducted for Some Time in
Southern Santa Fe County.
WRITTEN BY cLoYo n CHAPNAN
WELL kNOwE IN THIS CITY

Cloyd NJ Chapman of the Edison lax
oratories ct Menlo Park, N. j.. wh
had charge of the Edison experiment.
works at Dolores on the Ortiz min
grant in southern Santa Fe county
and is we'll and favorably known i
Santa Fe, gives the following descrip
ton with the sanction of Thomas A
Edison, of the process perfected a
Dolores for the separating of the gol
from the placer ground covering sucl
large area in southern Santa r
county not only on the Ortiz grant bu
on San Pedro creek and in the Tuertos
and which placers have been worked
from time immemorial by hand dry
washers. The description appears r
last weeks Engineering and Mining
Journal, an authority on mining and
engineering matters in the world.
"In spite of the fact that there are
several hundred patented processes for
the separation of gold from gravel
without the use of water, there is not
one as yet in general use on a large
scale. Dry washers of various forms
have been employed and are still at
work in various parts of the world
upon placers having little or no water
at hand but they are usually hand
machines, and are only practicable
where the gravel carries values suffi-
cient to pay the operator out of the
few tons at most which he can handle
in a day, and the greater part of the
gold is left in the gravel.
About six years ago, Mr. Edison
took up the problem of producing a
process which would save the gold in
a very large, and judging from numer-
Gus reports that had been made on it,
a very rich placer located at the foot
Of the famous Golden Mountains in the
arid region of New Mexico, on the Or
tiz Mine Grant. 25 miles southwest of
Santa Fe. To what extent he succeed
ed is a part of the purpose of this
article to show.
"T11e difficulties to be faced were
many and great. First, the process
must be exceedingly inexpensive to op-
crate. The gravel must be excavated,
concentrated and the tailings disposed
of for not more than Is cents per cubic
yard.
Second, it must have large capaci-
ty in order that great quantities OF
gravel can be treated daily in plant
of practical size.
"Third, it must save high percent
age of the gold. Very little gold can
be spared in the tailings when the orig
inal gravel carries so small an amount.
Fourth, 1t must save all sizes of
gold from few thousands of an inch
to the size of peas or larger.
"After three years of work, covering
the known processes for dry concen-
tration and many original methods, 1t
was found that if certain conditions
could be brought about the simple
method of letting the gravel fall
through horizontal current of air.
and saving that portion of the mater
ial which was least DETECTED from Its
vertical course by the blast, gave the
best results.
"The necessary conditions We're, first,
a blast free from all puffs.
Second, blast Of perfect uniform
velocity throughout Its entire cross Sec
ton: that Is, the retarding action of
the walls of the chamber or duct
through which the blast passed must
be overcome so that the blast must
not be stronger in the middle than at
the sides.
Third, all particles of gravel and
gold must enter the blast at uniform
low velocity.
Fourth, the material treated at one
time must not vary beyond certain
Units
"In time all requirements were met
and a machine was taken to New Mex"
leo, where an experimental plant was
erected upon the placer for the work.
ing of which the process was Develop
ed. This machine was a wooden af-
fair. 1t had revolving roller sthat
discharged the gravel from a hopper
upon shelf from which it fell into an
air blast created by a centrifugal fan
discharging its air through two
screens. A parting board divided the
heavier portion of the gravel. the gold
and iron or black sand, which falls in
TO a chute, from the lighter portion
which fell into the tailings chute. A
lattice prevented eddy currents Of air
from going down the chutes. The end
of the apparatus farthest removed
from the fan and nearest to the tall
ings chute was open
"By suitable adjustment OF the
speed of the fan, the position OF the
parting board and the rate OF the reed
Of gravel concentrate was obtained
the details of which follow.
"The gravel treated by this machine
was taken from shafts sunk at widely
distributed points on the placers. The
material, therefore, was of variety OF
qualities. From some shafts the gold
was fairly coarse, from others exceed
ingly fine. From some the gravel was
very coarse and stony, from others 1t
resembled clay in its fineness of grain.
Some Of the gravel treated carried
more than 80 cents per cubic yard, some
less than 3 cents.