The objective of blasting is to optimise the cost-effectiveness of the excavation process through the fragmentation and displacement of rock from its in situ condition to a highly diggable muckpile. The aim of wall control is to optimise the stability of a rock wall exposed by excavation through the control of fragmentation, displacement, vibration and overbreak. The success of mining and quarrying operations depends on both of these aims being achieved despite the conflict of purpose that may exist. This course will examine the mechanisms and possible extent of damage to the rock structure behind the face from blasting and the influence that has on the stability of pit walls. The course includes consideration of the mechanisms of rock breakage that operate within a blast and considers means of optimising wall damage adjacent to the blast. The influence of burden relief, geological structure and application of field controls to verify the use of design parameters will be stressed. Common techniques of wall control, including pre-splitting, will be detailed.
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