Detonating cord and methods of making and using the same

Abstract

The velocity of detonation of an explosive such as detonating cord (18, 22) is controlled by the addition of a diluent to the explosive, e.g., to the core of the detonating cord (18, 22). An explosively inert diluent, or a diluent comprised of an explosive of lower brisance than the principal explosive comprising the core of the detonating cord, will serve to reduce the velocity of detonation. Such reduced velocity of detonation has beneficial effects in certain operations, including cleaving rock (10), wherein it is observed to significantly reduce radial cracks (24) and stickers (26) (long radial cracks) in the vicinity of the boreholes (12) in which the low-velocity detonating cord (18, 22) is functioned to cleave the rock (10). The low-velocity detonating cord also facilitates leaving behind a smoother face in cutting trenches and tunnels through rock. The method of manufacture of low-velocity detonating cord includes incorporating a suitable diluent, such as phenolic microballoons, into an explosive core of, e.g., PETN.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of patent application Ser. No. 09 / 863,795, filed May 23, 2001, entitled “Detonating Cord and Methods of Making and Using the Same”, which claims the benefit of U.S. provisional patent application Ser. No. 60 / 206,877, filed May 24, 2000.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention is concerned with detonating cord having a controlled energy release which is attained by incorporating a diluent into the explosive core of the cord to control the velocity of detonation of the core. The present invention is also concerned with a method of malting the detonating cord, and a method of utilizing the detonating cord to effectuate desired cutting or rupturing of any structures, rock formations or the like while minimizing undesired ancillary damage. [0004] 2. Related Art [0005] Detonating cord is, of course, well known in the art and comprises a solid core of high expl...

AI Technical Summary

Benefits of technology

[0015] Reference herein to “reduced-velocity detonating cord”, “low-velocity detonating cord”, or the like, means a detonating cord whose explosive core contains a diluent which reduces the velocity of detonation of the detonating cord as compared to an otherwise identical detonating cord which does not contain the diluent.

[0022] Another method aspect of the present invention provides a method for making a detonating cord as described above. The method comprises the steps of preparing an explosive material by admixing a first explosive with a diluent selected from the group consisting of (a) explosively inert diluents; (b) a second explosive having a velocity of detonation less than that of the first explosive; and (c) mixtures of (a) and (b), the diluent being present in an amount which reduces the velocity of detonation of the detonating cord as compared to an otherwise identical detonating cord in which the explosive material contains no diluent. The explosive material is enclosed within a tubular sheath to provide a detonating cord having a core of the explosive material.

Problems solved by technology

High peak outlet shock wave pressure causes rapid pressure loading of the structure, e.g., rock, being ruptured by the detonating cord, which nucleates fractures causing them to spread into portions of the structure which it is desired to leave intact.

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