Eureka daily sentinel. [volume] (Eureka, Nev.) 1871-1887, 1874-09-09
L.NM ORlS.

Inc QUESTION OF the utlii/illpI q! LOW
grade ores is one which has, hereto
fore, been too generally overlooked
throughout cur State. In Europe Il
system of concentration i now and has
been for many years in successful op-
Grafton. and through its means very
nearly all crude ore is prepared for the
occurs throughout the. vein matter il
carefully separated by hand; whist
the residuum by far the major portion,
is crushed, .iigsed, passed over the
shaking table, round buddles and
plane tables until Il workable fro3Gct
is obtained, ready for the final maaip-
ulation, generally in the furnaces. Il
would surprise the majority Of ctr
millmen to learn how small a Weld i'll
the lead and the precious metals is
deemed worthy of a preparatory treat
ment. Il is not unusual to submit to
concentration ores which viii assay
W. to three per cent. OF lead, with
from five to fifteen dollars in silver to
the ton. 50 perfect, indeed, is the lie
chanical arrangement of many OF the
works that as high as sevcnty-five
stamps may he seen at work and not
Il single attendant i'll sight. The ba:-
teries are s~elf-feeders; :le crushed
pulp passes first into and over a series
of oblong boxes. fitted underneath with
pyram!d-shaped bottoms, freH
whence the sands. sinking each ac-
cording 10 their respective GRANTEES,
arc projected through Il metallic pipe
upona series of continually moving
shaking tables. The very tiae>.
shines are collected in properly pro-
portioned settling tanks. whence they
are taken to the buGdies or plane
tables.
The method Of universal application
throughout England, France and ter
many depends upon The agency Of
water. carrying along and holding IN Il
temporary su>pcn>ionthe various COM
minuted particles of ore and ganEue.
With us. however,. water III suili-
Gent quantity is not always a;ta.nahle,
and the inventive genius OF our people
has been taxed to find another me-
dunn, which shall combine i'll a more
delicate III al the requisites Of
quantity. elasticity and ease Of afrIi-
cation. All these have been found iii
Il combination of cru>hcrs, rollers,
separating sieycs and jets Of atmo,-
pheric air. The current OF air may he
regulated so that its wave-like i'm
pulse, act on the SUSPENDED ore parti-
e!es precisely as the water iii the liz
ging machines; in fact, being a more
attenuated medium. it does not offer
too harsh a resistance to.the most doll
cafe atom OF the eo-called noble silver
ores, and may be equally as well APP
piled to the commonest OF the base
lead and copper minerals.
Already, for several months, II OF
these dry air Commentators" has
been in successful operation III orr
State, and we learn that another and
larger machine is TO be set up in one
OF Il most successful mills. We
shall watch with more than ordinary
interest the progress Of the experiment,
which is. indeed, in the right direction
Here, right in our midst, there are
thousands, not to say millions. OF tons
of low grad. lead ore, which will assay
from five TO eight per cent. in lead,
and from, say, five to fifteen dollars il
gold and silver, which are practically
worthless. At best they are, ii 81 Al
irony character, only available as flax
Gould they he concentrated. say ipul
or five tons into one, they could bt
-melted with profit. We commend
this subject TO the careful consideration
of u furnace mon, whom we >halI
.ndeavOr 20 keep informed a, the *
pertinent 10 which we allrde lro
grCssee.