Effect of barrier holes on blast induced vibration

Blasting is one of the key elements of open pit mining. However, explosive usage may cause an environmental problem such as blast-induced seismic vibration. One of the solutions to the problem may be opening an artificial discontinuity as a barrier to shock waves. Such a phase is formed by lightly charging the barrier holes and firing them. This research is aimed at investigating the effect of empty barrier holes alone on seismic vibration. For this purpose, a series of field experiments were conducted in a dragline panel, Seyitomer Coal Enterprise, Kütahya, Turkey. In order to form a barrier at the centre of the panel, 30 holes were drilled on three parallel rows. The spacing between the rows was 1 m. In each row, 10 holes 1 m apart were drilled. The barrier holes were not charged and they were left empty. On the other hand, blast holes were charged and fired for rock fragmentation. Progress direction of the operation was from the ends of the panel toward the centre. At each firing, peak particle velocity (PPV) values were measured by two instruments located just in front of and behind the empty barrier holes. In this way, it could be possible to see how the empty barrier holes act. In total, 121 PPV values were recorded and analysed. Besides, in a number of experiments the barrier holes were filled with water. Analysis of data has revealed that a decrease in PPV of up to 18% has been detected just behind the barrier holes.