{"responseHeader":{"status":0,"QTime":2,"params":{"q":"{!q.op=AND}id:\"14612\"","hl":"true","hl.simple.post":"","hl.fragsize":"5000","fq":"!embargo_tdt:[NOW TO *]","hl.fl":"ocr_t","hl.method":"unified","wt":"json","hl.simple.pre":""}},"response":{"numFound":1,"start":0,"docs":[{"modified_tdt":"2009-06-16T00:00:00Z","thumb_s":"/b9/29/b92912dffdfb75546ee8f439e139e0eb0260799f.jpg","oldid_t":"altaav 289","setname_s":"uu_altaav","file_s":"/58/58/585800cf79a7b3d99d006cb17dca8c62dc02ade2.pdf","title_t":"No.11 - Page 4","ocr_t":"3 A 2- lb. tetrytol block is known to be the explosive equivalent of 2.5 lbs. of TNT. Thus the constants k. and k2 can be determined for snow conditions prevailing at the time of the above test. Here, for the tetrytol crater, W = 2.5 lbs., R = 3.25 ft. ( mean) and D = 2 ft. Solving for the constants, kj = 2. k and k£ = 1.5, and the formulas then read: 1/ 3 1/ 3 R = 2. k W and D = 1.5 W For the Plastimite crater, R = 2 ft. and D = 1- 33 ft. Substituting these values in the above formulas, the TNT equivalent of Plastimite is found to be O. 58 lbs. for crater diameter and 0.70 lbs. for crater depth. Mean of these two figures is 0.64 lbs. TNT equivalent for a 2- lb. charge of Plastimite detonated at the snow surface. Two- pound bags of Plastimite were used in routine, operational avalanche blasting. The subjective impression of the snow rangers using it was that Plastimite was definitely weaker than such customary explosives for this work as TNT or DuPont HDP. They felt a stronger blast would be preferred for reliable avalanche release. On the basis of these tests, we recommend a minimum charge of 5 lbs. of Plastimite or similar nitrostarch slurry be used for avalanche blasting. This is equivalent to 1.6 lbs. of TNT in explosive energy, which our experience indicates is just barely adequate for routine avalanche blasting. For large slopes and hard slabs, a 10- lb. charge would be preferred for more reliable avalanche release. The cost of even a 5- lb. charge of nitrostarch slurry is still about half that of a 2- lb. charge of commercial high explosives currently recommended","restricted_i":0,"id":14612,"created_tdt":"2009-06-16T00:00:00Z","format_t":"application/pdf","parent_i":14614,"_version_":1679953304788926466}]},"highlighting":{"14612":{"ocr_t":[]}}}