Patent ID: 8826820
Filing Date: 2014-09-09
Classification: F42D

Abstract:
1. In mining for recoverable mineral, a method of blasting rock 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, wherein 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.