Document Type : Review Paper
Authors
1 Amirabad St.
2 School of Mining, College of Engineering, University of Tehran, Tehran, Iran.
3 Professor. School of Mining, College of Engineering, University of Tehran, Iran
Abstract
The Power deck blasting technique is widely used in open-pit and underground mines to optimize explosive energy for effective rock fragmentation while minimizing adverse effects. This study examines the influence of primer location and air column length on ground vibration and limestone rock mass damage through field tests and numerical simulations at the Nardaghi limestone mine. A two-hole blast using the Power deck method was performed, with vibrations recorded by a three-axis seismograph. The maximum particle velocity reached 70.22 mm/s at 11 meters from the blast. Field inspections indicated that damage was limited to areas around the blast hole openings. Numerical results show that placing the primer at the bottom of the explosive column reduces ground vibration by 37% compared to middle or top positions, whereas the top primer location causes greater surface damage. Damage at the blast hole bottom was comparable across all primer locations. Fixing the primer at the bottom, the effect of air column length (0.4 to 2 meters) on vibration and damage was studied. Increasing the air column length up to 1.4 meters increased vibration, but longer lengths led to significant vibration reduction. Maximum rock mass damage occurred at an air column length of 0.6 meters, indicating optimal energy transfer. The results highlight the critical effects of primer position and air column length on blasting outcomes. The best primer placement is at the bottom of the explosive column, and the optimal air column length is 0.6 meters to balance vibration control and fragmentation efficiency.
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