Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1880-10-01
NEW PROCESS OF ROASTING.


ton with chlorination works uea
Mnrphy's. A prospective revolution
in quartz mining is claimed as the re
suit. II says: The point Of interes
in the mill il the new roasting pro
cess. This is according to the paien,
Off. A. Willard, taken ont three ears
ago, and was never practically tested
on large scale until now. The ore
has snlphurcts. also free gold, and
contains sulphur, lion. aniimony, ga
lena and zinc blend, arsenical iron,
copper pyrites and gray copper. Any
Of these combinations, eau be worked
by this process. The ore is crushed
dry, then elevated into scAcw con-
veyor aud mixer, mixed with sawdust,
dampencd and carried to bin above
the furnaces. The bottom Of the furn-
ace is perforated iron plate, and but
little fuel is used underneath. Tie
heat is low. combustion and heat by
means Ut the sawdusi among the par
ticles Of ore. An air-blast undear-
meath the perforated bottom Of the
fun forces air through the mass
through tile interstices left in the
place of the consumed sawdust, oxi-
dizing The metals and preparing them
more perfectly for chlorilIation than
by any other process yet devised.
Sulphur, arsenic, antimony and some
zinc are driven uT by the air-blasl.
The roast is dead one and entirely
free from sulphate Of iron. III work
ing silver ore where chlorination il |
wanted, 2 per cent. to S per cent. 81 /
salt is added From three to six
hours are occupied in roasting, accor
Ing to the ore. After the ore is roas t.
ed II Is thrown out on the cooling floor
and passed through cornish rolls aud
then passed into the chlorination builds
ing on the upper floor. The floor oc-
eul,ics onc-half the width OF the build
ing. On the floor stand ten tanks 81
two aud u half tons capacity, eacl,
with false or movable bottoms. In
tl'esc,the finely pulverized ore is laced
dampeIird aud chlorine gas introduced
underneath by pipes, dissolving the
gold aud silver. The ore is then COW
cred with water and the precious
metals leached off into ten tanks on
the floor beneath, where it is prec-
plated IN the form of black sylvia
mass, three-fonrihs gold in bulk. The
water is then drawn, the mass collcct-
ed IN the laboratory, where Mr.. Morse,
the chemist, by the aid of chemicals.
cleans up the gold. They are particu.
iarly successful with galena and ziuc
ore, getting higher returns than by
any other process. They extract 90
per cent OF the assay. They own the
" Hard patent-right in Calaveras
aud have sold one right to a
company who have erected nll a,
West Point. They are doing some
custom work, charging SIS yer ton
Ior ore. They are working two out
81 hall dozen mines that they own. !
aud run the mill steadily. Ia Their ,
m'ne (the Orc i'lata) the lori-wall !
streak assays SlS5 per ION. The other, r
hanging wall seven feet thick. as 4
says $50 per ton. They propose to !;
rect concentration works ana en- !,
afge their capacity. They can con- s.
'entrate for $3.50 per toa, reducing
rom 20 TO loo tons of rock 10 The :
weight and bulk Of one ton. Th.y
can then concentrate aud chlrinale \
or from 80 TO So per ton. In this
Ray much custom work may be done q
ow-grade rock crushed at a distance y