Weekly Arizona journal-miner., 1904-07-27
A VISIT TO CROWN KING MILL
BY JOURNAL MINER REPORTER
The Plant Working Splendidly and Results
Obtained SatisfactOry=Preparations
Being Made to Start Big Tunnel.

| tailings pass from one to the other by
gravity, there being a system of
worms inside which passes the tail
| ings from one end to the other and
keeps them in constant motion. The
tubes are surrounded by steam jackets
which heat the inside very hot, and
the vapor is drawn off by fans, and
! by the time the tailings have passed
through this seventy feet of tubes
they are dry as powder.
From the dryer they are discharged
into an elevator which carries them TO
a trommel. The oversize passes to a
grinder and is returned to the from
mel until it is all ground to the de-
sired 6neness and then it is discharg
ed into bins from where it is fed into
plunger feeder and then in a Iaun-
der and thoroughly mixed with water.
Two pumps then carry this pulp to
/ the top of the mill where it is divid-
ed, if desired. for the two large
/ Dimmick sizers. As it leaves the
last pump it passes over a Pierce
amalgamator which catches any parti-
cles of free gold that might be in the
pulp. 1t then passes to the sizefs.
The sizers in use in this plant are
surely marvel of construction and
are the patent of one of the best con-
cenrating men in the west, j. o.
Dimmick, of Denver. who has person
ally installed them and is at present
in charge of the concentrating depart
ment of the plant, and through his
courtesy many of the details of the
mill were explained to the reporter.
The sIzers are fourteen feet long,
about ten feet high and built in
"V'' shape, the material being steel.
The sizing of the pulp is done by
! system of drafts, currents, gates,
pockets, etc., there being no screens
used. EThe operation is based entirely
/ on scientific principles and the results
obtained from it are the absolute
wonder of everyone who has seen it
work. The pulp is divided into nine
grades or sizes and from an overflow
of water from the top something like
40 per cent. of the water is here saved
and returned to the mill for Sc, this
water being absolutely clear. At the
bottom of the siZer, where the pulp
has settled, there are nine places to
draw off the pulp and these discharge
into launders which carry it to the
different tables and vanners as de-
sired. The discharge from numbers
one, two, three and four is carried to
Whitley concentrating tables which
concentrate the mineral in the pulp
the zinc. The discharge from numbers
five, six, seven, eight and nine is car
ried to the vanners for concentration.
The clear iron concentrates from the
four Whitley tables are ready for the
smelter when they come off the tables,
carrying about three per cent. below
Nu6 DbDollN III ol4ANos anu oAC WI III
between s45 and $50 per ton, the con-
centration being between three and
four tons into one. This product con-
tains A. per cent. iron and per cent
copper and is an ideal pyritic smelter
product.
The zinc and iron concentrates from
the four Wolfiey tables and from the
six vauners are carried by worm
conveyor to an elevator and by that
lifted to another set of Jeffrey dryers
where they are thoroughly dried as
before and discharged into a large
hopper from which they are fed into a
Campbell pneumatic elevator and
carried through this 10y a current Of
air to the rooster where the concen-
trates are submitted to a very short
roasting process. It has been demon
strated that iron sulphides. which are
g not of magnetic character, by very
short process Of roasting can be
changed into iron pyrrhotit, which is
of magnetic character. 1t is for the
purpose Of producing this effect that
the concentrates are submitted TO the
roasting process. The time required
is very short, being from two to five
: minutes after the concentrates have
reached a cherry heat.
) After the roasting process has been
completed it is then discharged into a
, Campbell pneumatic cooler and car
, ried by very strong draft of cold