Orica Explosives Technology Pty Limited

Orica International Pte Ltd

Michael John Noy

Geoffrey Frederick Brent

Tapan Goswami

Peter Dare-Bryan

Alan Minchinton

Dane Peter Blair

A method of blasting rock, in mining for recoverable material, comprising drilling blastholes in a blast zone, loading the blastholes with explosives and then firing the explosives in the blastholes in a single cycle of drilling, loading and blasting. The blast zone comprises a high energy blast zone in which blastholes are partially loaded with a first explosive to provide a high energy layer of the high energy blast zone having a powder factor of at least 1.75 kg of explosive per cubic meter of unblasted rock in the high energy layer and in which at least some of those blastholes are also loaded with a second explosive to provide a low energy layer of the high energy blast zone between the high energy layer and the adjacent end of those blastholes, said low energy layer having a powder factor that is at least a factor of two lower than the powder factor of said high energy layer. The high energy blasting method provides improved rock fragmentation through increased explosive energy concentration while simultaneously alleviating deleterious environment blast effects.

High energy blasting

A method of blasting rock, in mining for recoverable material, comprising drilling blastholes in a blast zone loading the blastholes with explosives and then firing the explosives in the blastholes in a single cycle of drilling, loading and blasting. The blast zone comprises a high energy blast zone in which blastholes are partially loaded with a first explosive to provide a high energy layer of the high energy blast zone having a powder factor of at least 1.75 kg of explosive per cubic meter of unblasted rock in the high energy layer and in which at least some of those blastholes are also loaded with a second explosive to provide a low energy layer of the high energy blast zone between the high energy layer and the adjacent end of those blastholes, said low energy layer having a powder factor that is at least a factor of two lower than the powder factor of said high energy layer. The high energy blasting method provides improved rock fragmentation through increased explosive energy concentration while simultaneously alleviating deleterious environment blast effects.

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 () 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 () 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.

Method of blasting

A method of blasting in which rock pile profile associated with a blast field is controlled by precise control of the detonation delay times between and/or within individual blastholes in the blast field, in combination with the control of one or more other blast parameters. One or more of the blast parameters may by blasthole geometry, explosive charge or blast initiation location.

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Cardiff South, Australia

Michael John Noy