GB449909A - Improvements in or relating to blasting explosive cartridges and borehole charges - Google Patents

Abstract

449,909. Blasting - cartridges ; explosives. DU PONT DE NEMOURS & CO., E. I., Wilmington, Delaware, KIRST, W. E., 54, Du Bois Avenue, Woodbury, New Jersey, McCOY, J. W., Park Drive, Wilmington, Delaware, and WOODBURY, C. A., R.F.D., No. 2, Middletown Road, Media, Pennsylvania, all in U.S.A. Jan. 4, 1935, No. 377. [Classes 9 (i) and 9 (ii)] A composite blasting-cartridge or borehole charge comprises a quantity of detonating explosive having a cross-sectional area of not less than 3 sq. in., a booster charge extending over only a part of the length of the charge or abutting against the end thereof, and an initiator for the booster charge, the detonating explosive being capable of complete detonation by the booster charge but having a limited sensitivity regulated within the following limits. The upper limit is that the explosive cannot be detonated by means of a commercial No. 8 blasting cap. The lower limit is defined by either of two criteria; one is that the sensitiveness should be greater than that of a composition comprising 5À5 per cent paraffin and 94À5 per cent of ammonium nitrate of such fineness that 25 to 40 per cent passes a 100 mesh screen, the composition having a density of 1À15; the other is that the explosive when tested unconfined should be completely detonated by a blasting cap in addition to a booster charge not exceeding 1000 grms. of trinitrotoluene having a density of 0À95. Many ingredients and examples are described including compositions of ammonium nitrate with or without sodium nitrate, dinitrotoluene or nitrobenzene, and paraffin or fuel oil.