Daily inter mountain. [volume] (Butte, Mont.) 1881-1901, 1900-03-29

Cu' oHO was OuIlC ny MT. 6rOWn0 Oy Jay
work. The machinery was made by the
~. +. Allts company of Milwaukee, Wis.,,
and shows excellent Workmanship.
Ground was broken for the mill in July,
1899. and but for the unavoidable delay
In getting the iron work from the build
ers the mill would have been in opera
ton. as intended, on October 18th. Even
with the delays a preliminary run was
made on December 26th, or about OF
year after cessation of work at the Nam
moth in Coloma. This bespeaks much
Tor the energy and ability of the engi-
neer, MI. Browne, who, unaided, planned,
AMI n developed a company,
erected the mill and put it in operation
In less than IL months.
A portion of the stock was delivered to
cry Comapny Of Denver for the Estate
patent rights to use their dioxide process
in connection with the other methods. BY
the use of sodium dioxide the length OF
time of extraction by the cyanide Is re-
duced to about -four days. thus avoiding
tanks, which would materially add to the
original cost of plant. However, II. Is be-
leved by the writer that the advantages,
received by the Denver company for the
use of it's patents are far in excess Of the
saving made by he Reduction company
in interest on investment needed, except.
perhaps. when the latter company shall
have extended the use of the dioxide pro-
cess to many other mills in the state,
The purchase rates are as follows: Up
on delivery of the ore, and after treat
ment of the same 80 per cent of the as
say value in the gold, n in silver, ii
over 2 OF. per ton, will be paid after de-
duction. for moisture. In addition to this
a charge of IS per ton Is made for treat
ment. On these figures a fair profit
heretofore was thrown on the waste
dump. The expense of hauling is $3.50
per ton, and of treatment is SIS, leaving a
value of $3.50, of which 80 per cent, or
$7.65, is net profit to the owner. The eff
feet Of this ready market for such low
grade ores must be very helpful.
The general plan of treatment of the
ores can readily be seen by a study of the
cuts of the exterior of the mill and OF
the plans of the ground floor and eleva-
tin. Five receiving bins of 20 tons ca
pacity each receive the ore after 1t has
been weighed, each lot being kept in a
separate bin. From the bins the ore is
drawn into a car which delivers it to the
8 by Is Blake crusher. 1t is then ere-
waited and again delivered into the rolls.
from which it is elevated to the sampling
floor. Here it is sampled to one-twen-
tieth by a Vain sampler. The ore is
then run into the proper bins according
to it's character with respect to it's free
milling or concentrating properties. The
ore is all put through the stamps, of
w AAASAA An ! ~ HAS 6Vs IL Cx4C u
is principally quartz-bearing iron oxides
1t is stamped to a No. 40 mesh, but If 1t
contains the sulphides, as pyrite, chal-
copyrite, tetrahedrite, etc. a 30 mesh is
used.
For concentration of the plate tailings
four double-deck Wiley tables are pro-
vided. A hydraulic sizer is used to- size |
the material for each table. 1t consists
of a V-shaped trough divided into four
compartments through which h pulp
aorryS CAn~or. ~ x.e 4-n s~%- ~~@ln $780,
partment from the bottom keep the pulp
agitated and effect a sorting according to
size and weight. The feed pipe for each
table is connected with a compartment
furnishing the desired sized material for
the table in question. The lower deck of
and stroke independently of the upper
deck. No attempt is mad to treat sep
arately the tailings from the four stamp
batteries. The shines which are obtain
ed at the overflow of this trough are
either allowed to run away or may be
concentrated on a blanket concentration.
In regard to this part of the milling moth
ing can be said definitely until expert
mentatiOn shows the proper method. The
manager. Mr.. A.. B. Browne, states that
yet he has not sufficient data to en-
able him to describe how to catch all of
the values of gold without allowing the
shines to reach the cyanide tanks. In
a future ape will be given the results
of the different experiments. together
with the fuller treatment of the ques-
tions of metallurgy invoked in the mill
ing of these ores. The 80 per cent. of
which must be extracted before the cost |
of the ore to the company is met, calls
for the best of milling. and it is at this
point in the mill that the greatest care
must be taken.
The tailings from the tables are all de-
livered into the cyanide tanks, of which
there are four, having a capacity of 100
tons each. The arrangement of these
tanks n also that of the intermediate !
and standardizing cyanide tank is plain
ly shown in the floor plans. The tanks
are provided with vacuum pumps for fill
In this battery of pumps is al
so a force pump which forces the ex- |
hausted cyanide solution back into the !
standardizing tank to be recharged with
more cyanide and used over again.
The different floors of the mill are ar
ranged one above the other on the hill
side, which has a slant of about 30 de-
grees. The floors are arranged in the
order taken up in the description, the last
of which is the precipitating floor, offices
and laboratory.
The power for the machinery is fur.
nished by an SO-H. p. Erie balanced.
valve engine, which is connected with
5O-H. p. boilers. Steam from the
boilers is used to heat the Office. leach
ing. concentrating and stamp floors. The
mill is lighted throughout by incandes-
cent lamps furnished by a small 1OO-lamp
dynamo. The capacity of the mill is 60
tons in "a hours. and can be easily in
creased by additional machinery. provis-
original plans. Everything throughout
h mill shows both good workmanship
and ingenuity In design, and altogether
the plant is a model of it's kind. correct
in design and complete in details.
RV@eyY . - 1