The Placer herald., 1873-11-15
FIGURES FR8ss A GOLD MILL.

The following interesting items which
smack so much of local Improvements and
developments, we clip from the S. F. Alta
and make room for them, feeling assured
they will be read with avidity by quartz
miners throughout the country, and es-
pecialy in this section.
The modern improvements in working
gold ores are worthy of note. Improved
mill-machinery and amalgamating apparatus
have largely red ced the per ton expense
and increased the yield. There are but
few quartz mills now in he State that ad-
here to the old system of simple amalgama-
ton coppers, blankets and the arastra.
Having had occasion 70 pass through
Placer county recently, | visited the St.
Patrick's Gold Mining Company's mill
near the town of Ophr. Mr.. Morkler, the
the anal gamator, explained to me the
modus operandj of his gold saving ma
chimes, which are so effective and perfect
in their working, that | will give a short de-
scripion of the mill for the benefit Of parties
interested in the business:
The mill contains Is stamps of $50
pounds each, fed by Cochrane Automatic
Self Feeders; stamps drop GO per minute
fall from to 10 inches; crushing capacity
usingNo. 6 punched screens-20 tors pei
a hours.
The mortar, below the discharge inside
front, has strip of copper 10 inches.
Five-eighls of the gold product is caught in
the mortar. From tie discharge the pulp
flo over brood ap ons Or copper plates
these catch PIG of the product; thence
over II feet Of blankets. The banke
concentration is passed through the Atwood
amalgamator; which not only acts as an
amalgamator, but serves as a cGncentrator
for the richer sulphureis and sand, which are
taken off every two hours and ground in a
Knox pan, yielding (the amalgamaor and
concenrator) 1-lG of tie gross results.
The pulp that flows over the blankets
passes through Spitz casting Ga V box),
furnished with hydrostatic pressure, ad-
mitted at the bottom, sufficiently strong TO
keep the pulp alive, thereby acting as a
concentration, the particles of gold and richer
suphurets remaining at the bottom, which
is filed with quicksilver, the lighter sands
flowing from the top. This is cleaned up
daily by drawing the bottom plug, and does
not stop the work an instant.
From the Spi.z casting the pulp flows
into, first and second IL 9ndry concentrate or
two to each battery; thence through
thirty feet of sluces II by 5 inches, with
half-inch grade to the foot. AT the bottom
of the sluice there is arranged an iron gate
raised by a over-shot, driven by the water
and pulp that flows away. The gate is
regulated to raise one inch per hour, thereby
keeping back all particles that have the
greatest specific gravity-gold, sulphurets
or aurferous sand The box filing in
twelve hours, the flow of pulp is turned
into common sluic =, and The contents Of
the full box shoveled into a rocker and con
centrated. These concentrations with the
Hendy concentration are ground in Wheeler
pan, from which is obtained thrce-sixteenl bs
of the values of the run. From the pans
the pulp or shines pass into a slime pit,
where it is reconcentrated, shoveed out and
stored up eventually TO work by chorinaton
the pans not saving over sixty per cent. Of
the values of the sulphurets.
The motive power of the mill is steam,
the engine automatically governed by enc
Of the most perfect and safest governors
known, "the Hendy."
From the mill to the office | found the
same perfect system of order Superin-
tendent Crossman showed me series of
tests, workings of custom rock, with GER
tilted statements from owners of the quartz,
proving conclusive!y that the old style OF
simple amalgamation pays heavy loss to
the owners of the ore