Patent ID: 6035784
Filing Date: 2000-03-14
Classification: E21B,E21C,F42B,F42D

Abstract:
A device for fracturing a hard material, comprising:a cartridge; anda stemming means for holding the cartridge in a hole in the material, the cartridge being located adjacent to an end of the stemming means and including:a cartridge base positioned adjacent to the end of the stemming means; andan outer cartridge housing attached to the cartridge base, a first portion of the outer cartridge housing containing an explosive and a second portion a space for controlling the gas pressure in the hole, wherein at least a portion of a surface of the explosive, that is adjacent to a surface of the cartridge base, is positioned at a distance from and separated by a gap from at least a portion of the surface of the cartridge base to dissipate a detonation shock wave generated during detonation of the explosive and thereby retard damage to the stemming means by the detonation shock wave.