The Placer herald., 1865-02-04
m the S. T. Mining and Scientific Press.
important to Mine Holders.


rh- high importance Of roasting silver
ores for the purpose ot extracting the pre-
cious metals with a greater success than can
be done by the 50 called raw working, gives,
has already, for more than century back,
claimed the attention of metallurgiss and
scientific men. In 1884, Won Born, 10 81
emma, introduced, with great success, the
roasting of ores with salt. Since then uany
Improvements have been made, bot still pre-
sens some serious drawbacks, which have
puzzled the brains OF some OF our most
scientific men to overcome. These obstacles
are, frs, the slowness Of the process; second,
the great expense attendant on the large
amount Of labor needed.
This expense (which in Washoe, for ex
ample, amounts to $40 ton for roasting
alone) added to the further expense Of eX-
tracing the silver, exceeds in many instan-
ces, the total value Of the metal. Thus it is
that so many companies whose mines yield
no richer metal than that of $50 or $40
average, have been obliged to suspend work,
despairing OF ever realizing any returns from
their investments.
The obstacles above mentioned appear to
he removed at last. The writer of this has
seen lately, at 4l6 Market street, a newly
invented roasting furnace in operation, which
invention reduces the expense Of roasting to
one half its former cost, which immense adj
vantage will turn into source of profit what
hitherto has been nearly vaueess-we aIude
to what till now has generally been thrown
away as rubbish, $50 to $40 ore-which
amounts to fully FIVE eighlhs Of the produce
Of our Pacific silver mines.
The advantages this furnace possess are
First, one man is able to attend to six ovens;
Second, it can be erected in less time and
with less building material; Third, it takes
much less fuel than other furnaces require;
Fourth, it needs no stirring Of the ore, hav.
inc an apparatus inside to do this necessary
operations; Fifth, the ore is roasted more uni
formy; and Sixth, it will roast quicker than
in any other furnace. Il can be taken to
pieces and carried on mule. back, anywhere
that a mule can travel; it occupies less
space, requiring therefore less roofing than
others, with many other advantages.
A those who understand the principle Of
roasting, would do we'll to convince them
selves Of the correctness Of the above state
ments by a personal inspection of this nven
ton, which, in the writer's opinion, will
create quite q revolution in the working of
silver ores, Frightening tie prospects Of
many Cat presen) despairing mine holders.
j. CoGHo, Mining Engineer.
REMARKS. We have seen and examined
the above described apparatus for roasting
sui phurets. The principle Of It's constyuc-
ton is revolving cylinder, lined with fire
brick, and ribbed upon It's inside with con
verging screw threads, which operate to dis
tribute the sulphurets, from end to end Of
the cylinder and assist in the discharge Of
tue same, when the roasting is completed
through an opening at central point Of the
surface of the cylinder. This apparatus, to
all appearances, possesses decided advantages
over the ordinary reyerberatory hearth for
roasting.