The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1893-04-22

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ninety-four a minute. Tho screens are
nine BY forty-eicht inches. and the one for
the battery crushing fine ore is forty-mesh
and the one for the battery crushing coarse
and harder ore. t~hirty-mesh.
Al the Empire mill tho idea had been
worn. by false bottoms as near as possible
to the bottom Of the screens, so the blows
would splash more pulp through them. For
the same reason the mortars Of the mill at
Penobscot we Q made narrower. The OPP
Grafton of the Penobscot, AZ we'll as the
Empire mill. has proven that these ideas
were correct. and that a greater amount OF
rock could be crushed in q given time in
mills made after the new pattern. While
the mill is in actual operation about five
tons Of rock to the stamp are crushed in
twenty-four hours.
10 arrive at the weight OF the ore. ono
skipful is weighed i'll the morning and one
in the afternoon of each day. From an
average of these the weight OF each skipful
is found for that day. The number OF
skipfuls is carefully kept by two ersons.
1 he waste that is cast on the dump is aver
moisture deducted from the gross weight of
the number of skipfuls hoisted during the
day, leaving the net number of dry tons
hoisted in twenty-four hours.
To crush forty-five tons of rock in
twenty-four hours 43. 200 gallons of water
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ute per stamp.
The metal is saved on silver plated
copper plates covered with gold amalgam.
The grade of these plates is one and three
fourths inches per foot. There Is also one
additional plate to each l~attery. and one
plate over which the. t~ailings from both
batteries run. The tailings then pass
through a sluioe over 1000 feet long, which
is lined with smalgamated copper plates.
The battery plates are cleaned every day.
and the others as often as necessary. The
amalgam is kept bright and soft. but not
SO soft Ms to run. The plates are continu-
ally watched and kept in order. and the
amount of water 40 regulated that the
heavy mineral will not settle on the plates.
Any defect in the aplalgam on the plates is
corrected. and when the plates are cleaned
they are put IN perfect order before the
mill is started. Stiff whisk brooms are
used for securing the plates, and if the
amalgam gets hard it is scraped off with II
knife. The plates are also washed after
each clean up with q week solution of cya-
hide of potassium. Nearly so per cent of
the gold in the ore is saved o n the
plates.
The mill was started last December,
working twenty-five days in that month.
During that time there was crushed / $50
tons Of ore. from which 1891 per ton was
extracted, the tailings averaging $1.30
per ton, saving rs per cent of the assay
value.
In Janunry the mill ran thirty-one days,
crushing 1900 tons of ore; $685. worth OF
gold extracted per ton. tailinCs averaging
81 cents q ton. Per cent OF metal saved,
el15.
The cost of operating the mine and mill
was as follows:
Mining PEI PEE; e Tn q F Feb b
Milling lilo lW LIB
General expense .........- 81 90 SO
Mlne-permanent Improvement q .43 .65
Totals. $40 SkOl
February expenses were increased By cost
of insurance and greater mine development.
The cost of insurance was 40 cents a ton
for the month.
The Longmaid Brothers are giving les
sons in mining and smelling at Pcnobscot
which all owners of mining properties in
our mountains would do we'll to heed. Any
one visiting the property will be kindly re-
ceiyed and full information concerning the
working of the property given. A knowl-
edge of the convenience of working and
handling ore at this mine might save many
expenses in locating and working mills, as
we'll as lessen the first cost of erecting
buildings.
In q few days less than three months
there was produced from this property.
mostly from waste put back into the slopes
by those who formerly worked the mine,
over 500, 600 worth of gold. Nearly the
whole OF this amount was cast into one bar.
which was exhibited for several days at the
Merchants National bank in Helena.
FL. M. BEADLE.