A study on influence of blast-induced ground vibration in dragline bench blasting using signature hole analysis

Abstract

In dragline bench blasts, large amount of explosives are used in each hole making it the largest blasts of mining industry. The explosives in dragline blast holes liberate huge energy in surrounding rockmass and hence generates higher ground vibration. The generated ground vibration may cause loss to property or irritation to nearby population. In Khadia coal mine opencast project, there is a huge risk of loss to property and sensitive structures as there exist a village Kota basti and also a power plant named Shakti Nagar power plant in near vicinity of the mine. The empirical techniques are not precise and may result in erroneous prediction leading to unsafe blasting. In this paper, the signature hole dragline blasts were conducted and ground vibration waveform recorded is simulated using a signature hole analysis technique to predict the production blast-induced ground vibration. The production blasts were planned using echelon delay sequence and straight-line hole to hole delay sequence keeping the charge per delay the same. With the help of signature hole simulation, the optimum delay sequence was determined and accordingly the production blasts conducted. It was observed that by using straight-line hole to hole delay sequence pattern, the PPV values may be reduced up to 48.26%. Also, it has been found that the predicted PPV values using signature hole simulation techniques are close to the actual values with root mean square error (RMSE) of ± 3.48 mm/s and ± 2.73 mm/s with echelon and straight-line hole to hole delay sequence patterns respectively.