Omaha daily bee. (Omaha [Neb.]) 187?-1922, 1908-08-24
RECRINDINC PLANT At WORK
Homestake Mine Gets Larger Percent.
age of Values from Ores.
NEW PROCESS PROVES SUCCESS
Experiments Extended over Year
Before Construction work Was
Started--Three Pans Now
Are Running.

LEAD S. D., Aug. 23.-(special)-In its
effort to get from its ores the highest per-
centage of the values contained in them
the Homestake Mining company is ever
ready to spend money in making expert
ments to that end. Its latest experiment
one which was proven a success before 1t
was installed on large scale, has
been a "regrinding plant" This plant
which was begun about six months ago, Is
sequel to a complete series of experiments
extending over a period of about a year
and which proved to the satisfaction Of the
officials that such plant would be sue
cess At present only three of the pans
are running, but the other four viii be put
into commission as sooE as the feed pipe
can be put in.
The object Of this plant is to take out
from the mill pulp and regrind that ma
terial which is too coarse for the cyanide
mill BY means of this regrindng a better
extraction will be secured. This material
at present gives up under cyanidatioD only
about 50 per cent of its values, but under
the new process an extraction of not less
than IS per cent is looked for.
Process of ReErtndinE.
The tailings come to the regrinding plant
from the Homestahe, the Star ard the
Anxious mills and are separated in twenty
eight classifying cones of two sizes, four
teen of each size. After the granular mat
ter of the size desired has been separated
from the shines which overflow from the
cones, it passes to the regrinding machines.
These consist of seven Wheeler pans ard
one tube mill. These each accomplish the
regrinding and furnish practically the same
results The tube mill is of the type that
has been used largely in South Africa, and
the Wheeler pans have recently been inr
stalled with great success in Australia
Before the reground material goes to the
cyanide mills it passes over seven slX-toot
plates and four twelve-foot plates, all
silvered copper, where a certain percentage
of the values are obtained. Thence II goes
to Cyanide No. l. where the remainder oil
the IS per cent extraction is obtained The
plant is installed IN a remodeed edition OF
the old Jig house and will employ about
six men,
Capacity Two Hundred Tons
The total capacity Of the plant for the
present will be a little less than 200 tons
and the average value of the proauc'
treated will probably be about 81 TOM
this value will, of course, vary with the
value of the ore. The proportion OF TINS
material is about one ton of material 10
thirteen of ore About 900 tons of ore
pass through the three mills above men
toned, daily; from this is secured the ap-
proximately 200 tons which win go through
the regrinding process. As about 80 per
cent OF the values are already saved II
will be readily seen that the extra eNtrac-
ton will be valuable to the company on
account of the immense amount of ore
handled. The extra 80 per cent gained by
! the regrinding will amount TO about $40
every twenty-four hours, or about $4,000
a Year This is but one of the several ways
in which the Homesidkc within the last
few years has effected great savings by
the recovery OF small amounts On large
! quantities Of ore.
/ \Vni.e TINS plant was b-ing erected, a
( new clarifying mouse adjoining / was also
| being put up, d gang OF m beng en-
( LIUyeu " wurR upon the Two at the same
! ,ime. lnis clarifying house is also in
/ operation now. Iue UbJgc, rs - accom-
. pI sh the Clarifying OF the water that comes
/ Iruul tue Ili.ls more effectively ana tuLy
/ This water when clarified goes u the
shines pant in DeauwUod 40 be used
/ ,nere. i l.is plant requires a large amouni
OF water, on account oI the qualify used
| 10 sluice out the presses aTter the charge
is treated. a force OF men Will be ~
work Tor possibly TWO OF three weeks Yet
but by the END Of that time II is expected
to have everything IN running order an-
the regrinding plant operating at ITS ful
! capacity