Flyrock prediction and control in surface mine blasting
- Calder and Workman, Inc., Washburn, ND (United States)
- Queen`s Univ., Kingston, Ontario (Canada). Mining Engineering Dept.
Flyrock can be a serious hazard associated with blasting. Many surface blasting accidents involving injury result from excessive flyrock beyond the protected blast zone. Numerous cases of equipment damage at the mine, quarry or construction site have resulted from flyrock. Fragments propelled beyond the property limits of the operation have also caused injury and damage. This paper discusses the path described by flyrock ejected from the blast and the factors that affect the throw distance. The initial fragment velocity and angle are most important in this regard. A range of initial velocities that are associated with flyrock incidents are suggested. Proper blast design is essential to avoiding excessive flyrock. Acceptable scaled depths of burial are required at the top and face of the blast if flyrock is to be avoided. The blast must be properly implemented according to design. Total quality management of blasting operations is essential to eliminating flyrock incidents. Geology also plays an important role. Mud seams and open jointing are particularly important in this regard. Voids in the ground, whether intersected or located between the blasthole and the face can cause dangerous flyrock situations. Where geology is a factor geological mapping of the bench faces should be performed to project the occurrence of adverse zones in future blasts. Drills equipped with modern performance monitoring equipment may also provide information useful for adjusting explosive loading in the presence of mud seams and voids.
- OSTI ID:
- 433677
- Report Number(s):
- CONF-940144--
- Country of Publication:
- United States
- Language:
- English
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