Elk City mining news. (Elk City, Idaho) 1903-1913, 1905-05-06

biased in favor of the method they are
using and perhaps have little knowledge
of methods used with varying ores and
in other districts.
2. The second method, by working a
carload or less at a testing works, has
decided advantages over the first in that
facilities will be provided for getting
exact samples and weights and that the
test probably will be conducted by men
with somewhat wide knowledge OF
methods of ore treatment; and IN that
the machinery will be provided with
means of adjustment so that its oper-
alton can be more nearly suited to the
particular ore. However, the rapid
progress in methods and machinery for
the treatment of gold and silver ores
renders it impossible that any plant
should be equipped with machinery for
testing all methods or that its machin-
cry will not before long get behind the
times. Assuming, however, that the
testing works is equipped with the ma
chjnery best adapted to the ore, the
difficulties of such tests are: First, the
tendency is to send an insufficient
amount of ore, or what is sent is not
the average output of the mine, which
the mill to be built later on will have to
treat; secondly, that considerable por
ton of the ore used for the test must
have been milled before the machinery
can be properly adjusted to enable nearly
as good a recovery to be extracted as is
possible; and, thirdly, good deal of
labor and care is required in perfect
cleanup-indeed, in tests by plate ANAL
gamation, accuracy in the cleanup is
practically impossible.
3. The third method, by making
small scale tests by the labratory, fol-
lowed by the erection and experimental
operation at the mine of only ono COM
plete unit of the plant, but this of full
working size, has the disadvantages as
compared with the first and second
methods that the owners must go to the
expense of the purchase of a unit of
the plant, for its transportation to the
mine and for it's erection in working
order there, before any of the ore has
been actually treated on working scale
by the machinery intended to be en-
ployed. 1t has the further disadvan-
tages that the mill will not be treating
it's full output so soon that it will cost
somewhat more to erect first one' unit
and later to erect the rest than to en-
stall the complete mill at once.
But the disadvantages of the third
method, above enumerated, are heavily
outweighed by its advantages, which
are numerous and important. Assuming
for the present what will be discussed
later, that complete labratory tests by
competent men will correctly indicate
the most advantageous process or COM
bination of processes, for example,
whether amalgamation, concentration,
teaching or smelling, or combination
of two or more of these, is required,
and what form of the one decided upon
is the best, whether the ore must be
roasted, ETC., it is possible, from the
the mine plant of full working size
adapted to the ore, except perhaps as
regards details, but so nearly the best
possible plant that it can be made such
by simple, inexpensive alterations which
can be effected on the ground. The one
unit plant can then be used as testing
works, in the same way as would a
neighboring mill or general metallur-
gical labratory, to determine with per-
cision extractions, costs and details OF
operations and to expose in working
any faults of mechanical construction,
should they exhist, so that they can be
corrected in the one-unit and avoided ir
the complete mill to be erected later.
Plans for. the complete mill should be
, drawn before the unit is erected, anC
the unit built in accordancevwith them
The one-unit plant, for the purpose Of
testing, has all the advantages and none
of the disadvantages of either a neigh
boring mill or public protesting works
and has other advantages peculiarly its
own. y Its advantages over other meth.
DDS MAY be grouped under four heads
l, ore supply; 2, modern machinery; g.
, full working scale; A, economic or bus.
mess reasons.
l. There is an abundant supply OF
ore to be had for the cost of mining it
and conditions will enforce, or at least