Dynamite is exploded by a detonator. There are two styles of 

 detonators, one known as a blasting cap and the other as an electric fuze 

 (pronounced fu-zee). Both are small copper cylinders about a quarter 

 of an inch in diameter and from one and a half to two and one-eighth 

 inches long, which contain a small quantity of a very powerful explosive. 

 This explosive is quite sensitive to heat and shock and a hard, sharp blow 

 may explode it, so detonators must be carefully handled. 



The heat to detonate a blasting cap is provided by the spark from a 

 piece of fuse, one end of which has been pushed into the open end of the 

 blasting cap, and fastened there by crimping the blasting cap on it with 

 a cap crimper. When the other end of the fuse is lighted it burns through 

 slowly and when the fire reaches it the blasting cap explodes. 



Nothing weaker than the No. 6 (red label) Blasting Cap or Electric 

 Fuze can be depended on to properly explode dynamite. 



When more than one charge of dynamite is to be exploded at the 

 same instant, the blasting must be done electrically. If the charges are 

 too far apart for the wire of one electric fuze to be connected directly 

 to that of the next one, it is necessary to use connecting wire to join them. 



The electric current for detonating electric fuzes is produced by 

 the blasting machine and is carried to the electric fuzes through leading 

 wire. 



Method of Exploding Dynamite 



The detonator, to do its work properly, must be closely surrounded 

 by the dynamite, because air in the open space between the detonator and 

 the dynamite acts as a cushion when the detonator explodes and lessens 

 the shock to the dynamite. This may result in an imperfect explosion 

 of the dynamite with but little work done. When the charge of dynamite 

 is all pressed together in a mass one detonator is sufficient to explode it. 

 If it is strung 'out for fifteen or twenty feet in a deep bore hole it is 

 generally best to use two detonators. 



Preparing Caps and Fuse 



Placing the detonator in the cartridge of dynamite is called priming 

 it, and the cartridge with the detonator in it is called the primer cartridge 

 or primer. When the charge consists of more than one cartridge the 

 primer should generally be loaded last or next to last. 



INSERT FUSE IN BLASTING CAP 

 TAKE OUT BLASTING CAP BUT DON'T TWIST CAP AROUND 



FIG. 101 FIG. 102 



119 



