Fergus County argus. [volume] (Lewistown, Mont.) 1886-1946, 1895-12-05

Il
reduced the cost of obtaining the
metal. and made possible the work
ing OF mines containing a very small
percentage of gold. In the Colorado
gold district the best results i'm this
direction have not yet been reached.
1t is predicted that when the time
comes for the enormous deposit of
low grade ore proved to exist at
Cripple Creek to bc treated anywhere
near as cheaply as the cost at
Johannesburg, Cripple creek will
produce more gold than Johannes
burg. where ores are treated by stamp
mills, the "tailings" being passed
through cyanide mills. Ten years
have been spent in reaching the high
state of efficiency and economy there.
Rossiter Raymond, a mining en-
gineer who has hal experience in the
Colorado mines, said:
/ The reduced cost of obtaining gold
from ,orssslor rock cor tanning it is
due:
I'D To the numerous new deposits
|
years. Such deposits are, of course.
more cheaply mined while operations
are conducted near the surface. In
this country the increased activity
in gold mining is doubtless due largely
| to the encouragement OF silver min
ing by the fall III the price OF silver.
\ large army ofprospectors, formerly
seeking for silver mines in preference
to gold, is now looking for gold.
But the most important new develop
ments in gold are those in South
Africa, where the deposite Though
| they have been overestimated in the
speculations of the London stock
market) are unquestionably of i'm
mense value and dproductivecapacity
"(2l To the increased efficiency of
mining methods and machinery
high explosives, power drills. im-
proved hoists and pumps, cable
tramways, etc.l, which permits large
quantities of low grade material to
be handled ut "a profit.
't3l To the cheapening of labor
and supplies by the extension oi
railroads, the increase of population,
etc.
''t4J To the multiplication tespeci-
ally in this country of smelling and
other reduction works, which can
utilize other ingredients i'm gold
bearing rock lead or copper directly
and iron or silica as fiuXes), SO as to
he able to pay to the miner, i'm some
cases, the full value of the gold.
"(5) The only innovation i'm metal
lurgical methods for the extraction
of gold, apart from variations in
smelling processes, is the so-called
cyanide process, which promises to
treat cheaply certain classes of ores
and failing Its principal competi
tor is the chlorination process, which
is very old, but has been much i'm
proved, and is now the most perfect
: of all methods for gold extraction
} from material suitable to it. This
: process usually requires N prelimi
| nary roasting and it is claimed
that the cyanide process can bt
successfully operated without that
preliminary Probably the ultimate
verdict of practice will be that eacl
process has it's special field, and that
the choice between them will depent
upon a careful consideration of the
f. elements of the special case-naturt
of material, cost of chemicals ant
skilled labor, expense of plant. etc
At the most successful of the Southern
gold mines, the Halle mine in Soutl
Carolina, a profit is secured from
material containing as mined abou,
81 per ton. This is first crushed anC
amalgamated in a stamp mill, an(
then the sulphide ores, unaffected by
!. amalgamation, are saved by mechan
ical concentration, to be roasted
chlorinated, and leached.
Rock yielding free gold to the ex
tent OF 50 per ton can be mined and
: amalgamated with profit under
favorable conditions as to the siZ,
] and accessibility of deposit. cost O
power. wages, etc, provided the
operation is on a large scale. The
New York Evening Post.