490 



SEISMIC METHODS 



[Chap. 9 



board at the desired location. Reflection shot holes are generally of small 

 diameter, and the primed charge is pushed down with a tamping stick con- 

 sisting of several sections connected by hook joints. Several sticks may 



George E. Failing Supply Co. 



Fig. 9-27. Failing seismic shot-hole drill; view of hydraulic. 



be taped to a piece of lath, or they may be placed in a tin torpedo. Nitra- 



mon cans are loaded with a spoon attached to the end of the loading pole. 



Shot holes are drilled in various ways, depending upon conditions. In 



easy drilling soil, the use of hand augers is quite feasible, particularly if 



