The record-union., 1895-04-09
THE MAGNITUDE OF MINING
DETRITUS.

DEIhlIUS.
When the Parks brush dams were con-
structed in the Yuba River, not far from
Marysviile, they resisted the first flood
of the season about two days. The dam
was constructed at a point where the
bluff banks of the river separated nearly
two miles. The dam itself was con-
structed across a somewhat narrow place,
and was in length about one and half
miles. The river canyon at that point
was level for distance of two or three
miles. The impounding space thus in
closed represented about four square
miles twenty feet high. The flood filed
up this space to the top of the dam which
resisted its force for the time already in
dicated, and then broke in several places.
After the subsistence of the waters it was
visited by a representative of this paper,
who found that in most places the basin
was entirely full, the debris remaining
rising to the top of the dam. 1t was evil
dent from the appearance of things that
the entire impounding basin would have
been filed in that flood, and that all
subsequent movement of material in sus-
pension would have passed over the dam.
The dam itself cost about S250,0O0. The
first irresistible conclusion from IL > facts
on the ground was that nobody had ade-
quatelY estimated the quantity of mining
detritus forced into the streams and
ravines. 1t was evident from that ex-
pertinent that the cost Of constructing re-
strsining works exceeded the gross cut
put of the mines of California, and the
experiment was for a long while aban-
doned.
We now quote from letter of the Sec
retary of War, transmitting the report of
the California Debris Commission SUBJ
mitted by the Chief of Engineers, under
date of Washington, December 4. 1894, as
follows:
The total amount of material mined under
permits from October 1, 1898, 10 October i
1894, is estimated at l ,5OO,0 cubic yards.
The available storage provided at present,
and partially and wholly ompleted for future
nperations is estimated at s 800 900 cubic
yards. Comparing these figures with IS OOO.-
900 cubic yards, estimated TO have been
mined in 1850, and the estimated amount q
SeCedJ hundred million cutie yards GUdi{ubIe 10
to be 1cOrked, it viii be seen that the system
provides for the present working of only a
small percentage OF that possible under unre-
stricted mining. however, there are TN
doubtedy many mines which have not yet
made application TO the commission Tor
which there is available storage as feasible Az
that prescribed by tie commission Tor other
mines that are working under permits.
The significance of Inc foregoing will
not be apparent by casual reading. The
first statement shows that in one year
from October /, 1893, to October 1, 1894,
100000 cubic yards of earth was forced
into the channels of the streams. This
was the equivalent of bed OF earth four
and one-half miles long, one mile wide
and three feet high: or two and one-quar-
ter miles long, one mile wide and six feet
high. All this detritus was carried into
the channels of the streams and remains
q menace to the low lying lands.
The same statement shows that there
was partially and wholly completed for
future operations storage capacity for
S,500,000 cubic yards. But the Debris
Commission reports that in 1850 there
was mined and placed in the canyons,
ravines and streams of California 3S000,-
600 cubic yards, The Debris Commission
speaks of several hundred millions OF
cubic yards available to be worked"
Let the people of California, who value
the navigability OF her waterways, and
who believe that the 100000 people men
aced by the devastation to be wrought by
hydraulic mining debris should be pro-
tected, weigh these words carefully:
'The estimated amount Of several hum
dred million cubic yards available to be
worked"
1t is to work this available volume Of
earth that hydraulic mining is being re-
yived. With several hundred million
cubic yards available to be worked, and
upon which work is already commenced,
there is partially and wholly completed
for future operations restraining capacity
for 8, 500, 600 cubic yards. Whatever earth
has been sent down or is to be sent down
will be incorporated into the river and
bay systems of California. When we
see an official statement that in