Correlations between physical properties of PPAN and detonation characteristics of ANFO

ANFO (ammonium nitrate and fuel oil) is the most useful industrial explosive in Japan as well as other countries in the world because it is safe and easy to handle, and relatively inexpensive. Recently, ANFO has become diversified in Japan also. The low-density and high-performance ANFO has been widely used in particular because of being possible to decrease the specific charge without changing the conventional blasting condition. ANFO, which has high sensitivity and reliability of detonation, is necessary for the blasting with relatively small borehole diameters of 65 mm to 105 mm. at mines and quarries in Japan. This study attempted to determine the influence of the pore diameter, the pore volume, and the particle diameter of PPAN (porous prilled ammonium nitrate) on the detonation characteristics of ANFO for thirteen kinds of PPAN. It was found that the pore diameter and the pore volume of PPAN had correlations with the detonation characteristics of ANFO. The initiation sensitivity, the detonation velocity, and the ballistic pendulum value increased with increase of the pore volume and decrease of the median pore diameter. The degree of the influence of these internal physical properties on the detonation characteristics varied with the particle diameter of PPAN.