Magnitude of Vibration vis-a-vis Charge per Delay and Total Charge

The socio-eco-environmental constraints and increase of dwellings in and around the mine workings have very recently made the blasting activities to be of high risk in day-to-day excavation works. Vibration and noise having a geometric attenuation with respect to distance, sometimes poses problem in estimating its magnitude from the predicted best-fit propagation equation derived from wide range of data. Again, for same charge per delay, the attenuation characteristic varies with the change in total charge. This paper, explains that depending upon distance of concern, the magnitude of vibration depends not only on charge per delay (CD) but also on total charge (TC) and ratio between total charge and charge per delay (TCCD). Considering the widely accepted USBM square-root scaled distance predictor equation, the authors wanted to emphasize that after understanding the attenuation characteristics of blast induced vibration magnitudes, the data should be categorized into various suitable range of distances. Thereafter, predictor equations should be determined for each category of distance and with each charge parameter, namely, CD, TC and TCCD. The equation having least standard error of estimation (SEE) should be considered as the best-fit propagation equation for that range of distance. The best-fit propagation equation, thus derived, would enable the practicing mining engineers to have an optimum maximum allowable charge parameter to be blasted in a round and have a cost-effective and eco-friendly mining operation