The Kenosha telegraph. [volume] (Kenosha, Wis.) 1860-1888, 1876-09-07
A BIG BLAST.
The Explosion at He'll Gate-The Entire
Mass to Go Up at One Time.

Mass to Go Up at One Time.
The great explosion at Hell Gate is
now certain to take place during the
latter part of September, and contrary
to reports, which have been generally
circulated, the entire mass Of rock viii
be demolished by one terrific explosion.
The work of tunneling and boring is
now ended, and nothing remains undone
except the preparation and insertion of
the cartridges.
| The tunnels radiating from the main
shaft, and likewise those crossing them,
are all cleared out, leaving the upper
crust of rock supported on 172 piers,
each eight feet square, but varying in
height from twenty feet near the shaft
to ten or twelve feet hear the outer cir
conference. In the roof Of rock thus
formed 8, 500 holes have been bored in
an upward direction, ranging in depth
from three to eleven feet, with uniform
diameter of three inches. These holes
will be the receptacles of the explosive
material, which will be dynamite where
! the rock is hardest and ordinary vulcan
powder where the superintendent mass
is more friable and easier to blow to
pieces. AS the floor OF the tunnel slopes
outward from depth of thirty-t two feet
to forty feet below low water, and the
depth of water required for investigation
in the neighborhood of New York is only
| twenty six feet at mean low water, it is
plain that after the explosion and the
subsequent dredging there will be am
pie room for the largest ships in the
world to reach New York bay through
the waters of the sound, and thus make
saving of time on the voyage to and
from Europe.
Nitro glycerene was for time con
templated as the most suitable explosive
agent; but on mature consideration Ii
was rejected, not only as being too dan
gerous in the manufacture, but also be-
cause some of the charges are liable TO
slip out of the holes prepared for them,
and in such an event nitro-glycerene
would be iaule to explode prematurely.
Dynamite, which is composed of % per
cent. of clay and IS per cent. of nitro
glycerine, was finally selected and it is
calculated that each charge will break
up twenty cubic yards, there being in or
about 10000 cubic yards in the entire
mass to be exploded. A bomb-proof
chamber has been prepared for the oper-
ators, at distance of 800 feet southeast
of the main shaft and in the direction of
the Ravenswood road. In this chamber
will be placed at least 200 galvanic bat
teries Of the pattern known as Groves
and each of these will explode from sew
enteen to twenty charges. A most in
geAious scheme has been devised. by
which all these batteries will be brought
into action at the same time, and then q
complete circuit will be formed, setting
off the entire $500 charges together, and
utterly destroying the great plateau of
rock which has made He'll Gate SO dan
erous TO navigation.
! Gen. Newton has been unceasing in
his exertions, and has kept up q con-
slant series of experiments to insure per-
feet success when the great day comes /;
and there is no reasonable ground for
fear of any untoward accident occurring.
| The assistant engineers, who will have
practical charge of the operations on the
day of the explosion, will, according to
the popular belief, be placed in posi-
ton of great danger ; but this is only
visionary, as the utmost foresight has
been used to prevent any harm to the
operators.
The engineers are of opinion the only
apparent effect of the explosion will be
the hurting into the air of huge col
umn of water, with perhaps some bits of
rock, as the resistance of the superin.
cumbent water will prevent any except
few of the smaller masses from being
elected beyond the surface. AS soon as
ever the explosion is over the work of
dredging will begin, in order to throw
the channel open to navigation at the
earliest possible moment.-NeaO York
TVOTyd