The wave or flame that passes through a uniform gaseous mixture with a
permanent maximum velocity. The rate of the explosion wave is a definite
physical constant for each mixture. The explosion wave travels with the
velocity of sound in the burning gas, which itself is moving rapidly
forward en masse in the same direction, so that the explosion wave is
propagated far more rapidly than sound travels in the unburned gas.
Fay
a. Any chemical compound, mixture, or device that is capable of undergoing
a rapid chemical reaction, producing an explosion; a cap sensitive
mixture.
b. Any mixture or chemical compound by whose decomposition or combustion
gas is generated with such rapidity that it can be used for blasting or in
firearms; e.g., gunpowder, dynamite, etc. See also:explosive factor;
Morcol; permitted explosive; sheathed explosive.
c. In coal mining, there are two main classes permissible and
nonpermissible; i.e., those safe for use in coal mines and those that are
not. See also:coal mining explosives
A black powder obtained either by the rapid cooling of antimony vapor or
by the electrolysis of a solution of antimony chloride in hydrochloric
acid, using a platinum cathode and an antimony anode. When scratched, the
hard black mass deposited on the cathode will explode. The mass may
consist of a solid solution of antimony trichloride in metallic antimony.
Camm
A substance added to a permitted explosive to cool the explosion flame and
thus reduce the risk of igniting mine gases. The agent may be sodium
chloride and sodium bicarbonate. Nelson
A technique developed for deep-hole drilling in esp. strong and abrasive
rocks. In this method, a series of small underwater explosions are used to
break the rock at the bottom of the hole, the fragments from each
explosion being washed away by the flushing water.
Min. Miner. Eng., 1
Dusts that are combustible when airborne. They include metallic dusts
(magnesium, aluminum, zinc, tin, iron), coal (bituminous, lignite), and
sulfide ores. Hartman, 2
The ratio between the burden of a shothole in tons or cubic yards and the
weight of explosive charge in pounds; i.e., tons (cubic yards) per pound
of explosive. The factor is dependent on the rock and the fragmentation
required, but 5 st/lb (10 t/kg) is about average in quarry blasting.
See also:loading ratio
A force represented with separate values for the heat liberated by the
explosive decomposition and the detonating rate. Streefkerk
The limits of percentage composition of mixtures of gases and air (or
oxygen) within which an explosion takes place when the mixture is ignited.
Inst. Petrol.
See:powder factor
A device to give better support in underground mining operations. It can
be anchored more firmly than conventional bolts because the principle of
explosive forming enables the anchor to grip the sides of the borehole
along its entire length, if necessary. The key to the design is a seamless
steel anchoring tube, welded to the threaded end of the bolt. Exploding a
small charge inside the tube makes it expand to fit tightly in the
borehole. Water, wax, or a similar buffer surrounds the charge to
distribute the force of the explosion evenly and prevent it from rupturing
the tube. Its use may permit mining of mineral deposits formerly
considered uneconomic because of the hazards encountered in loose rock
formations.
The ability of a dust to produce violent effects; it is measured by the
pressure produced after the explosion has traveled a fixed distance under
standard conditions. Sinclair, 1
See:nitroglycerin
The weight of explosive per cubic feet (cubic meter) of rock broken. Also
called powder factor. See also:loading ratio
In explosives casting, large amounts of low-cost ammonium nitrate mixtures
are loaded into medium-sized drill holes in a usual ratio of more than 1
lb of powder per cubic yard (0.59 kg/m3 ) of overburden. The
explosive charges are detonated through millisecond-delay electric
blasting caps. When the shot is fired, a large part of the overburden is
blasted into the pit away from the high wall and up on the spoil pile
where it attains a favorable angle of repose. Woodruff
The ease with which an explosive will detonate or explode. Nelson
This method consists in soaking the ore thoroughly in water and then
heating to 180 degrees C under a pressure of 150 psi (1.03 MPa). The
pressure is then suddenly released, and the absorbed water is converted to
steam, which shatters and liberates mineral particles without harmful
overgrinding of the ore. Newton, 2
A surface building at a mine where explosives and detonators may be kept.
Nelson
A measure of the amount of energy released by an explosive on detonation
and its capacity to do useful work. Several methods of expressing
explosive strength are used, but in most cases the figures are calculated
from the deflection of a freely suspended ballistic mortar in which small
explosive charges are fired. Nelson
A method in which, by using an excess of explosives in the strip mine
bench, up to about 40% of the overburden can be removed from the coal seam
by the energy of the explosive, thereby requiring no excavation.
Encyclopaedia Britannica
A function frequently used when fitting mathematical models to
experimental variograms, often in combination with a nugget model.