PLANTING 79 



Never force a primer into a borehole, because the detonator 

 which it contains is sensitive to shock and might explode if too 

 much force is used. 



Tamping. After the charge is pressed home, as directed, put 

 in two or three inches of fine dirt or damp sand, and with a 

 wooden stick press it gently on top of the dynamite. Then fill 

 up two or three inches more of the hole, packing it in a little 

 more firmly. After five or six inches covers the charge, it may be 

 pressed firmly into place without danger of premature explosion. 

 The tamping material should be packed as firmly on top of the 

 charge as can be done without moving the electric fusee or blast- 

 ing cap in the primer, but it is not safe to tamp by a blow any 

 stronger than can be given by hand. Fill the borehole up with 

 tamping until even with the surface. The firmer and harder the 

 tamping can be made (without overlooking the above precautions) 

 the better will be the results. If the borehole is not properly 

 tamped, the charge is likely to "blow out," or at least some of 

 its force will be wasted. 



Do not use iron or steel bars or tools for tamping, because the 

 metal tools may detonate the explosives. Use only a wooden 

 tamping stick with no metal parts. 



Firing. Exploding the charge is called firing, and can be done 

 either by caps and fuse or electrically by electric fusees and a 

 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. 



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 thoroughly satisfied that there is no one sufficiently near 

 to be injured by the material thrown into the air by the blast. 



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 slightly damp 

 ground may injure the dynamite or even the detonator to some 

 extent, and in cold weather dynamite may become chilled or 



