Firing 



Exploding the charge is called firing and can be done either by caps 

 and fuse or electrically by electric fuzes and blasting machine. When 

 cap and fuse are used cut the fuse long enough to enable you to retire to 

 a safe distance. Fuse burns on an average of two feet per minute and 

 on page 140 is a table showing the line of safety to be observed for 

 various classes of blasting, as also the amount of fuse required to enable 

 the blaster to reach same. 



Never light the fuse or operate the blasting machine until you have 

 warned everyone near that you are about to fire, and until you are thor- 

 oughly satisfied that there is no one sufficiently near to be injured by the 

 material thrown into the air by the blast. 



Never investigate a misfire immediately. It sometimes happens that 

 the charge does not explode exactly when it should but does so a little 

 later. This rarely if ever occurs when firing electrically, but is not so 

 infrequent when fuse is used, because careless tamping sometimes tears 

 or abrades the fuse so that it will burn very slowly. A misfire with fuse 

 should not be investigated for at least one-half hour, but it is much 

 better to wait a full hour. When firing electrically be sure that all your 

 connections are OK and do not connect the leading wire to the blasting 

 machine until everything else is ready for the blast. This will prevent 

 some inexperienced person from accidentally operating the blasting 

 machine and exploding the charge before the blaster has had time to 

 reach the safety line. 



What To Do in Case of Misfire 



Never try to dig out the old charge. Make, charge and prime a 

 new borehole far enough from the first to make sure the tools will not 

 touch the first charge. 



Always fire just as soon as possible after tamping. In fact priming, 

 charging, tamping and firing should be done as quickly as it is possible 

 to do them thoroughly, because wet or even damp ground may injure the 

 dynamite or even the detonator to some extent and in cold weather 

 dynamite may become chilled or frozen which makes it insensitive. 

 When viewing a blast it is always advisable to look out carefully for 

 falling material which may be thrown farther than anticipated and a 

 position should always be taken so that the sun and wind will be at your 

 back. In any case the sun should not be faced, as in doing so it is 

 naturally difficult to discern material flying through the air. Look up in 

 the air, rather than at the stump or boulder being blasted. 



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