Bonners Ferry herald. [volume] (Bonners Ferry, Idaho) 1904-current, 1921-11-24
HUGE FLUME
IS FINISHED
IDAHO GOLD AND RUBY MINING
COMPANY READY NOW TO
BUILD CONCENTRATOR
FLUME COST OVER s3OO,OOO.OO
Detailed Description of an Immense
Engineering Project

The Idaho Gold e. Ruby Mining Co.,
OF Leonia, has just completed a $50
foot bedrock flume at cost of some
100000. An interesting and detailed
description of the flume is given in
the Northwest Mining Truth, pub
lished November Is:
"This work fills in the depression in
the stream bed just above the big
flume and will permit of uninter-
rupted movement of rocks of all sizes
through the plant into the tail race
beyond. Three carloads of cement,
laid to a thickness of inches in the
center and 4 inches at the sides of
curving bed, has been used in the
work and much more will be neces-
sary to fill in the crevices in the bed
for 1,600 feet further upstream and ly-
ing in between the plant and the hy-
draulic race. The latter work will.
however, be accomplished with much
greater speed and the management ex-
poets to have it completed within the
next 60 days.
Presented with this article is a re-
production of photograph of the six
foot section of the flume, which is s
feet deep, looking up stream The
second, or middle flume, is IL feet
wide and s feet deep and the spill
way nearest the east bank, also 12
feet wide and s feet deep. Footways,
feet wide, run between the sections,
thus permitting repairs in any one
without interruption of operations in
the others.
Through this flume the entire vol
ume of Boulder creek passes. 1t is To-
Gated 1000. feet below the present hy-
draplic race and at point where the
stream passes through a rib of solid
rock, commencing series of cascades
and falls aggregating descent of 400
feet in the first 500 feet below the
flume and about GOO feet in the mile
and a quarter traversed to the Koo-
tenai river.
"The aperture in the rock, through
which the stream pours, is 45 feet
wide at the throat and it is here that
the cement piers and headgates have
been erected. Back Of the cement
work, or down stream, log cribbing
was built up from bedrock over an
average width of 36 feet each log
being drift-bolted and cemented The
logs at the headgate end are 20 feet
long. two feet in diameter and set 8
feet in cement. Over this understruct-
ure the bedrock fumes and spillway
were constructed.
The flume is lined with 80 and 90
pound steel rails and pinch angle
irons, placed crossways, interlocked
<.,ts -,
is believed to be impregnable resist
ance to the heavy forces to which they
will be subjected. Between the steel
lining and a 3-32-inch grizzley, is an
undercurrent channel, 31b inches deep.
where the heavy sands are caught and
drawn off through launders, set 10
feet apart, into a 15,000-ton cement
storage bin, cut in solid rock on the
west bank. The first grizzly is 1872
feet long; then comes a grizzly set at
A-inch and another, the last section,
set at inch. The last two sections of
the flume are fitted with Hungarian
rifles 3 inches high, underneath
which are 4-inch undercurrent chan
nels. The coarse gold and rubies
(garnets), of which the gravel con-
tains myriads, will be caught in the
second and third grizzlies and drawn
off as in the first section, through
launders set 12 feet apart
Some idea of the size of the struc-
ture can be gathered from the fact
that approximately million feet of
logs have been used, with carloads
of so and 90-pound steel rails, 2 car
loads of rifle steel, carloads of drift
bolts and other steel and carloads of
cement. The cost of the structure, as
shown by the books Of the company,
has been 100000 to date.
"a large crew has been occupied for
some weeks in completing the heavy
cement work upstream from the flume
taking advantage of the good weather
but from now on a large part of the
force will be available for construc-
tion of the concentrating plant, which
will be placed upon the flume struc-
ture The floor has already been laid
and much of the table equipment com
pleted This work can now be fin
ished without delay from cold weather