The hydraulic press., 1860-01-21
MINING IMPROVEMENTS.

|
of hints kindly extended to him by Nature.
In art, science and mechanics, he is alike
her entire debtor. Even in the sordid and not
abstractay useful or noble pursuit of gold
seeking, she is the sole instructor. The ex-
perience of California miners has ledthem to
observe and initiate her, and to assimilate
their gold-saying processes more and more
closely to hers. At the beginning the "cra-
die" and the 4'topa" were efforts towards an
imitation, which was more nearly attained
when the ground slaicen and "hydraulic
process were subsequently employed. The
last mentioned mode tears down and washes
off the auriferous earth with all the power
and effect of natural forces directed by reas-
on; while the blocks and rifles lining the
siuice- boxes through which the dissolved dirt
is conveyed, are only cunning substitutes for
the gravel beds of natural water courses
These same gravel beds are now more close
ly initiated by lining the bottems with
cobble-stones, tapped one over another in
| IL
This idea was crudely adopted several years
ago, rocks being piled irregularly in the
slaices and there allowed to remain for an
indefinite time. The plan now is so system
atized as to be really valuable. Every Sec
ton of s1uice, or each box fourteen feet long,
is regularly paved as above described, the
stones held firmly down by mailing strips Of
board five and a half inches wide On each
side Of the box, and wedging a cross-piece
under these strips at the end of each box
AS soon as dirt and water have been allowed
/ to flow ever this gravel bottom, 1t becomes
immovable, as though set in mortar. The
paving can be rapidly accomplished, one man
being able to finish in day twenty five box
es fourteen feet long and thirty inches wide,
each. The material lies at hand in nearly
every mining claim, and costs nothing but
the labor of appropriation and selection.
The advantages of rock-sluices may be
briefly stated. Those who have had long
experience with them assert positively that
they save more gold than any other sluices
in use, and kind of gold which no other
sluces save at all. Mr.. Welch, of Indian
Hill, Sierra county, who has 1890 feet of
rock-sluice leading from his claims, declares
that he saves twenty per cent. more gold
than he ever did before out of the same dirt.
He has thoroughly tested the matter by hav
| ing alternate sections of rock and block
sluice, and invariably obtained most gold
from the former. He, as well as others, has
observed that the rock-sluices save the most
fine gold, the almost paipable powder of the
precious metal, which is generally lost. For
| the same reason that more gold is saved, less
quicksilver Is lost The rock-sluices also
effect great economy of lumber All other
sluces are lined with blocks of wood about
three inches thick, the cost of which, for
each section fourteen feet long and thirty
inches wide, is four or five dollars. These
blocks have to be frequently renewed, owing
| to the great friction of rocks, earth and
water rushing over them. In some instances
they will not outlasttwenty days ofwashng.
This was the case in the claims of Mr.. Welch,
where the saving effected by discarding
blocks amounts to very large sum. In his
| 1900 feet of sluice there are, say 164 boxes,
| days; in three hundred days each boxwould
cost, at four dollars for every new lining SEQ;
and the expense of the entire sluice for the
same period would be $9,840. In the Ken
| lucky claims, at Sweetland-where may be
seen very handsome specimen of rock
| sluice-the saving on blocks for sixteen
boxes, at four dollars each, amounts to about
| $64 every forty days that washing is done.
| Here, then, without reference to the superb
ority of rock bottoms as direct gold-saver,
is effected an economy that would alone
render many Improbable claims sources of
| income to their owners. One more recon-
mendation of rock-sluices is found in the
fact that they offer fewer facilities for rob-
berry. Thieves can help themselves in block
sluices by simply scooping up the amalgam
as it lies in narrow crevices between tie
blocks; but here it is buried in sand among
stones hard to remove and needing to be
| washed.
Rock-sluices are constructed upon grade
of from fourteen to sixteen inches for every
fourteen feet, the heaviest dirt, or that which
flows with least freedom, requiring the most
grade. They cannot ordinarily be laid through
tunnels, because these have to be run on as
light grade as possble-say one inch to
the foot-and block-sluices are used in them
as offering the least impediment to the flow
of rocks and dirt Their prime value is to
receive the ''tai!ings" at the mouth of TIM
nels, and convey them for long distances
down hill sides The boxes are usually
thirty inches deep and thirty inches wide, a
greater width being obtained sometimes by
constructing parallel lengths with a low
partition. Flat, oval-shaped rocks, the size
of mans hand, only thicker, and as hard
as possible, are selected for the bottoms
When the miner wishes to clean up, say af
ter washing ten or twenty days, the stones
are loosened with pick, washed off by al
lowing ten or twenty inches of water to flow