Patent ID: 6148730
Filing Date: 2000-11-21
Classification: E21B,E21C,F42B,F42D

Abstract:
A device for fracturing a hard material, comprising:a cartridge; anda stemming means for stemming a hole in the material, the hole containing the cartridge, the cartridge being located in a bottom portion of the hole and adjacent to a downhole end of the stemming means and including an explosive, wherein the explosive is decoupled from and is positioned at a distance from the downhole end of the stemming means to dissipate a detonation shock wave generated during detonation of the explosive to protect the stemming means from the detonation shock wave, wherein the cartridge includes a cartridge base positioned adjacent to the downhole end of the stemming means, the cartridge base having a second yield strength that is less than a first yield strength of the stemming means, and an outer cartridge housing attached to the cartridge base, at least a first portion of the outer cartridge housing containing the explosive.