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Show Snow safety work is a specialized use of explosives and some deviations from standard practices are authorized . The rules are summarized as follows: 1. A blasting party will consist of at least two men. The party leader will hold an avalanche blaster's card. 2. A blasting kit contains the following: sufficient explosive for the operation; sufficient detonators; hand- type blasting machine, blasting wire, galvanometer, friction tape, safety rope, snow sampler ( for digging shot holes in cornices). 3. Recommended explosives are the military demolitions tetrytol, C- 3 or TNT blocks. These have the following characteristics: high rate of detonation, stable to handle and store, insensitive to cold and moisture. A commercial explosive having the same characteristics is seismograph powder. The use of common dynamite is permitted but not recommended. It cannot be used for pre- planted cornice charges. The use of primacord is permitted. 4. Electrical detonation is mandatory in the Forest Service. 5. Limited amounts of the authorized explosives may be stored in the open, convenient to slidepaths under control. Such storage must be in remote locations and plainly marked. 6. Detonators and explosives will not be transported in the same pack. 7. The party leader will carry the detonators, arm and place the charges, and execute the firing, except under training conditions. 8. The minimum distance firing point to blast will be 50 feet plus a terrain barrier. The firing point will be in a location protected from secondary avalanches. 9. The party leader will be responsible for safety regulations throughout the area during a blasting operation and will provide for communications or signals if necessary. 10. Unused detonators will not be returned from a blasting expedition. They will be exploded in the final blast of the operation. Projectiles have many advantages over hand- placed and preplanted charges in snow stabilization work. The last two are laborious and time-consuming. They may be impossible due to the hazards of travel to the firing points. With projectiles, many slidepaths can be blasted from a single convenient location and in a very short period of time. With proper data, firing can even be carried out during storms. - 68 - |