1873 - Old Forge Coal Mines

54 ANNUAL REPORT OF THE
Unlike gun powder, its explosion is instantaneous ; the whole mass of
powder explodes as if a single grain. This quality, in connection with its
extraordinary evolution of gases, causes its explosive effect to be especially
great in solid substances. Its explosion produces carbonic acid, nitrogen
and water.
There are three methods of exploding it: 1st, by a violent explosion in
or into it ; 2d, by confining it in a strong vessel and applying fire to it, or
in heating the vessel sufficiently ; 3d, by a percussion shock so intense as
to produce heat and violence. Practically it cannot be exploded by accident
;
fire alone will not explode it, nor heat in any form, nor will any
amount of weight upon it or simple pressure of any kind explode it. It
cannot be exploded by any of the ordinary movements, accidents, or incidents
which attend its handling, transportation or use. The pressing it
into cartridges, or ramming into bore-holes with a wooden rod, however
hard, throwing it about, or even the crushing or violent overturning of
wagons, or the collision of railway cars, will not explode it. The burning
of gunpowder unconfined is not sufficient. When set on fire while under
confinement in some strong vessel, the burning of the powder produces
gases, which, finding no escape, at length cause a pressure so great as to
produce, with the least heat of the burning, an explosion of unburned
powder.
A vessel of the strongest tin has not the requisite strength. It, like
boxes, barrels and packages, &c, will be burst by the gases before the
pressure is sufficient to produce an explosion.
Cartridges.-—Except in special cases it is better to use the powder in the
form of a cartridge ; it is more certain and more economical in time and
power.
Fuse.—Ordinary fuse may be used ; but to make sure of a discharge in
all cases, and to keep the powder from being burned by fire from a leaky
fuse, the best fuse is recommended and a size to fit the caps precisely.
Caps.—Caps are manufactured for the special purpose of exploding
Giant powder They are more heavity charged with fulminate than ordinary
ones, and corresponding care should be taken in their handling and
use. A pair of cutting nippers, with their edges blunted, may be used in
securing the caps tightly and firmly to the fuse.
Drill-holes, charges, &c.—As to the diameter and depth of holes, and
where they should be made, and the direction they should take, and also
as to the quantity of powder to be used, and other matters, no definite
rules can be laid down for blasting with any explosion. As a general rule
for the drill-hole and charge for Giant powder should be comparatively
small. Experience has proven that f inch octagon steel with 3^ pound
hammers, by single hand drillers, are best adapted to use powder to the
greatest advantage. Holes of one inch in diameter are sufficiently large
for any ordinary work, and for light work smaller holes should be used
;
the hole should determine the resistance and charge of powder needed.
As Giant powder, from its quickness, is nearly as effectual without tamping
as with it, and cannot be advantageously used with tamping at all in
natural fissures, it is therefore recommended to take advantage of its extraordinary
quality as is practicable.
Charging.—The charge must fit and fill the bottom of the hole, and be
solidly packed. This is a prerequisite to an effective blast, thus : Take a
cartridge just the size of the bore, and cut it into sections from one to two
inches long. With a hard wood rammer as will run in the hole press these
sections into the bore-hole one by one, with sufficient force until ea«li section
is driven to the bottom and expanded laterally, so as to fill up all