The copper era., 1903-04-23
BIG MINES OF COCHISE COUNTY.
VA. Scott. Denver Mining Reporter.
CnMMOSW Attn NINE

/ 10 the DrdgoOu range on the west.
I The mine j. one of the many cone
shaped knobs which rise from 400 to
/ 700 feet above the general level OF the
plateau. The ground here was located
about ten years ago by Pearce and
sons, who had cattle ranch in the
vicinity. They gave an option on the
property some time later to John
Brockman, acting for Penn sylvania
parties and himself. The ore
promptly taken out proved very high
grade, the proceeds therefrom in 4
short time having been more than
sufficient 10 pay for the property at
the expiration OF the option. The
Commonwealth Mining and Milling
Company was then organized, and by
that company the mine and mill have
been operated for the past six or seven
years. L. \. +. Pcnrose j. president;
d. VI. Barringer, secretary and treas
urer; John BrOckman. general man
ager; \. y. Smith, assistant manager
ID. I. Swathing, mill superintendent.
Mr.. Brockman has been continuously
in charge from the first. The vein
has a dip southwark 80 degrees from
the horizontal, and has an east-west
strike. This vein ranges in width
from ten To- sixty feet, having a brecia
or cOnglOmerate, hanging wall and an
andesite foot wall. The gangue ma
terial, or vein filling, comprises quartz
chiefly, with some porphyry and tale.
The ore carries gold and silver,
mostly in the form OF a chloride.
Much OF the gold, however, is prac-
tically free. Thus far the mining has
been done with hand drills and this
method will continue so far as the
slopes are concerned, but Il Rand air
compressor and two power drill. have
now been installed for work in some
of the drifts. An incline doube-com-
partment shalt, following the dip OF
the vein, sinks 800 feet, and from this
levels have been run at 30, 80 and 100
foot station in both directions from
the shaft. In the aggregate there
are about five miles of underground
work. The incline mentioned sinks
about 100 feet below the nat
ural water level. AT sta
ton fifty feet below this level is
duplex, triple-eXpansiOn Dow pump,
capable OF handling 1000, 600 gallons
OF water in twenty-foIr hours. The
water is delivered to a stump tank at
this station by sinking pumps. On
the surface is another Dow pump. a
duplicate OF the one above mentioned,
which will soon be Installed at the
lowest level, as the flow Of water i
increasing. At present the mine is
producing about l, 800 ,OCO gallons of .
water per twenty-four hours. This
much more than supplies the water
necessary for mill work and steam use.
The power is supplied to mine and
mill by nine Woods safety water tube
steam boilers, equal to 120 to $50 III.
L. each. These boilers are equipped
with Wilgus oil burners and they con-
sumo from 100 to 40 barrels of crude
oil per twcnty-fOur hours. This
burner throws out a Jet of oil and i'm |
mediately below it a jet OF steam. 1t
is stated here that one pound of
Dil will evaporatc sixteen pounds of |
steam. and that oil here at 81 per bar
rel is equivalent To the best Juniper |
wood at 81 30 per cord or coal at s. per
-on.
The entire tonnage from the mine is /
passed through the cOmpany's eighty |
stamp :Hill, in which the values are re-
covered by neutrality-suspicious.. Be (
ore being fed to the stamps the ore
oils which are situated between the
,haft house and mill. The material
IN reaching the stamps is OF Il pretty
inform size and fees freely to the bat
cries. The stamps are each $50
pounds weight, drop about 100 to the
minute and the four five-stamp bat
cries crush about 220 tons Of ore
very twenty-fOur hours. The mill is
'uilt in two sections, each one being
riyen by separate mill engine.
The pulp passes from the batteries
hrOugh thirty-mesh screens to a sys-
cm of settlers by which the surplus
iater is taken out and returned to IT,
cad of the mill to re-entcr the bat
cries. The pulp is discharged from
he settlers to the pans provided with
lullers to keep the pulp in agitation.
IS IS generally known, the pulp in the
ANS is kept at a certain temperature
y the introduction OF cteam Be-
ldes putting quicksilver into the pans
18th which to amalgam9t e the free
old and silver, there are also added
ertain amount of blue stone, salt and
acid. The blue stone or sui '
hate OF copper absorbs the chlorine
1 silver chlOrides, Leaving metallic
liver. The sulphuric acid takes up
ny iron with which the gold or silver
light. From the amalgamating pass i
he pulp and amalgam are drawn off
lto settlers, from which the refuse
ulp is discharged, the amalgam set
ed aud the surplus quicksilver
trained out into the quick safes.
The impounded mill tailings. the re-
nlt of several years operating,
mount, approximately, to 300, 600
ons. a ten-ton exper mental plant
as been devised for the purpose OF