Further Studies on Sympathetic

A second investigation into sympathetic detonation of ammonium nitrate (AN) and ammonium nitrate-fuel oil (ANFO) was conducted to define the scaling law for safe separation from detonating ANFO. Both missileand non-missile-producing ANFO donors weighing up to 5,400 pounds were employed with equal sizedacceptors. The usual cube root scaling law was not confirmed; exponents for the relationship S = f(W) were for AN 0.51 with non-missile donors and 0.61 for missileproducing donors. For ANFO an exponent of 0.80 was indicated in the missile-producing case. ANFO in polyethylene bags appeared somewhat more easily initiated than bulk ANFO. The efficacy of barricades in protecting AN charges was investigated. Sympathetic detonation dis0 +4 1__ tances were reduced to 1/3 to 1/7 hen --Ne sand-filled barricades were employed. The investigation was extended to boxed dynamite with 1/ The previous investigation has been published as Bureau of Mines Report of Investigations 6746, Sympathetic Detonation of Ammonium Nitrate and Ammonium Nitrate-Fuel Oil, by R. W. Van Dolah, F. C. Gibson, and J. N. Murphy. 2/ Research Director, Explosives Research Center, Bureau of Mines, Pittsburgh, Pa. 3/ Project coordinator, explosives physics, Explosives Research Center, Bureau of Mines, Pittsburgh, Pa. 4/ Electrical engineer, explosives physics, Explosives Research Center, Bureau of Mines, Pittsburgh, Pa. Work on manuscript completed January 1966. . both types of donors. With 1,600 pound missile-producing donors and an equivalent weight of dynamite, initiation would be expected in 50 percent of the trials at 167 feet, the corresponding value in the non-missile case was 67 feet. The data developed in this program of sympathetic detonation will allow the development of a rational set of safe separation distances for e#ba/**ee,#ed AN, ANFO, and explosives.