US 5,099,763 A · Method of blasting

Abstract

A blasting agent is disclosed for use in a borehole having a pressure resistant closure. The blasting agent is used in combination with a primary initiating system comprised of a detonator and an initiator for the detonator. The blasting agent is preferably a semi-fluid explosive material having a predetermined sensitivity. The sensitivity is related to the borehole diameter and the initiating system's strength, wherein the blasting agent upon initiation is transformed into explosive products by means of reaction front which consumes substantially all the blasting agent as the reaction front passes through the blasting agent. The reaction front has an average velocity of propagation of beween 200 meters/second and 1,000 meters/second for at least 30% of the total length of blasting agent located in the borehole. Another aspect of the invention is a method of blasting wherein the average velocity of propagation of the explosive front in the blasting agent is in a range of between 200 m/sec and 1,000 m/sec.

Claims26

Dependent claims

An improved method of blasting comprising the steps of:

a) choosing a blasting agent of a predetermined sensitivity, having regard to the borehole diameter into which the blasting agent will be loaded;
b) choosing a detonator of a predetermined size having regard to the sensitivity of the blasting agent and the size of the borehole;
c) loading the blasting agent and detonator into the borehole to form an explosive charge;
d) closing the mouth of the borehole with a pressure resistant closure to confine the explosive charge;
e) detonating said detonation and thereby said explosive charge, and
f) transforming said explosive charge into explosive products by consuming substantially all of said blasting agent along a reaction front which passes through said blasting agent with an average velocity of propagation of between 200 m/s and 1000 m/s for at least 30% of the total length of said blasting agent located in said borehole.

3 more elements

A method of selecting appropriate parameters for an explosion in a stemmed borehole having a velocity of propagation of between 200 m/sec and 1000 m/sec, said parameter including an appropriate composition of blasting agent, an appropriate borehole diameter and an appropriate detonator, said method comprising the steps of:

1)
a) choosing a candidate borehole of a given diameter;
b) placing instruments into said borehole to measure the average velocity of propagation of an explosion in said borehole;
c) loading said borehole with a candidate blasting agent composition of a given sensitivity including the placement of a candidate detonating means;
d) stemming said borehole;
e) initiating an explosion;
and
f) measuring said average velocity of propagation of said explosion;
and
2) if the measured velocity is greater than the desired value of 1000 m/s, then selecting a smaller borehole diameter, or a detonator means of smaller explosion mass or a blasting agent composition of a lower sensitivity, or a combination thereof, and if the measured velocity is less than the desired value of 200 m/s, or if part of the charge fails to explode, then selecting a larger borehole diameter, or a detonator means of larger explosive mass or a blasting agent composition of higher sensitivity, or a combination thereof, and
3) repeating the steps of (1) above until the measured velocity is within the range between 200 m/s and 1000 m/s.

8 more elements

Dependencies are inferred from the claim text.

Method of blasting

Life of this patent

Method of blasting

Life of this patent

Abstract

Claims26