Method Of Blasting
First Claim
1. A method of blasting a section of rock to cause fragmentation of the rock without excessive ground vibrations, the method comprising the steps of:
- providing two or more groups of blastholes in the rock, each group comprising from 2 to 7 blastholes each of which is adjacent to another of said blastholes within the group;
loading each blasthole with an explosive charge;
providing blast initiation means associated with each explosive charge; and
inducing timed actuation of each explosive charge via the associated blast initiation means to propagate stressfields from each blasthole;
wherein the explosive charges in adjacent blastholes within any group of blastholes are actuated within 5 ms of one another, whereby the stressfields from the blastholes within each group combine prior to dissipation to enhance fragmentation of the rock, and wherein a delay of at least 8 ms occurs between completion of actuation of explosive charges in any group of blastholes and commencement of actuation of explosive charges in any adjacent group of blastholes, whereby the combined stressfields that propagate from blastholes within any group of blastholes at least substantially dissipate prior to actuation of explosive charges within blastholes of any adjacent group of blastholes.
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Accused Products
Abstract
Methods of blasting rock are disclosed and claimed in which blast holes are arranged in group of 2 to 7 blast holes. Within each of the groups, adjacent columns of explosive material (12) are actuated within 5 ms of one another Initiation of blasting between the respective groups occurs at least 8 ms after completion of initiation of an adjacent group. Initiation devices (13, 24) may be located at the lower end, upper end or both ends of the respective blast holes, depending on the stress field that is intended to be generated within the rock. As a result, environmental stresses such as ground vibrations are reduced, and the efficiency of rock fragmentation are increased.
18 Citations
30 Claims
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1. A method of blasting a section of rock to cause fragmentation of the rock without excessive ground vibrations, the method comprising the steps of:
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providing two or more groups of blastholes in the rock, each group comprising from 2 to 7 blastholes each of which is adjacent to another of said blastholes within the group; loading each blasthole with an explosive charge; providing blast initiation means associated with each explosive charge; and inducing timed actuation of each explosive charge via the associated blast initiation means to propagate stressfields from each blasthole; wherein the explosive charges in adjacent blastholes within any group of blastholes are actuated within 5 ms of one another, whereby the stressfields from the blastholes within each group combine prior to dissipation to enhance fragmentation of the rock, and wherein a delay of at least 8 ms occurs between completion of actuation of explosive charges in any group of blastholes and commencement of actuation of explosive charges in any adjacent group of blastholes, whereby the combined stressfields that propagate from blastholes within any group of blastholes at least substantially dissipate prior to actuation of explosive charges within blastholes of any adjacent group of blastholes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification