Blast Vibration Studies in Surface Mines

Abstract

Blasting is very important process for mining operation and a lot of explosive is used for this purpose. The blasting process and usage of explosives, however, remain a potential source of numerous human and environmental hazards. Various studies indicate that fragmentation accounts for only 20-30% of the total amount of explosive energy used. Rest of the energy is lost in the form of ground vibration, fly rock, air overpressure and noise. The specific problem associated with ground vibrations represents the human response to them. Blasting vibrations may also cause a significant damage to nearby buildings or various structures. In this project blast vibration study is done and it is interpreted for its effects in reference to the standards set by DGMS.

The study has been done with the help of geophones and Blastmate8.0 software. First of all the blasting operations were monitored through geophones at distances of 100m, 200m and 300m. The data obtained from the instrument were interpreted by Blastmate software and the graphical output was obtained from it. The Peak Particle Velocity (PPV), maximum charge per delay, air over pressure was recorded for each blast. After that the various observations were compared with the standards to determine the conclusion.

From the analysis of blasts vibration at the mines it was determined that the vibration level was less than 5 mm/sec for the blasts when recommended amount of charge per delay or safe charge per delay was used. The air overpressure value determined was in between 114 & 127.6 dB (L).

The results determined from the project indicates that the peak particle velocity, air overpressure generated due to blasting were within the limits. The safe charge per delay for the blasting operation was determined from the study.