Studying Peak Particle Velocity Due to Blast in Development Tunnels’ Face in Coal Stoping

Abstract

The impact of blast-driven shocks on the safety and stability of the underground coal mines has been well established. The seismic imperfections resulting from blasting depend on the total explosive energy released during blasting and the closeness of the development tunnel face to the stope face. Also, the quality of the rock mass wherein the whole stope face is located might pose considerable effects on the damages from blasting operations. Peak particle velocity is the main criteria for the evaluation of the damage caused by blast vibrations. Twenty nine logs were recorded of three indicators, namely the longitudinal, transverse and vertical, assessed in 29 blasting in Alborz-e-Sharghi underground coal mine and twenty sets of data extracted thereof was subjected to a series of statistical analyses. The nine remaining data were applied in validating the relations proposed herein. The present study analyses and evaluates the common equations used in predicting the ground vibrations. The results of the analyses indicated that the vibrations’ prediction scale, based on the cube root of the amount of the charge applied, is a better predictor of the vibrations in this underground mine. Studies have demonstrated that the scaled distance based on the square or cubic root of the delay charge mass might not be very appropriate for the prediction of PPV (peak particle velocity) in undersurface situations. Accordingly, the present study performs an alternative analysis based on multivariate fitness estimation. In the end, a PPV equation with an appropriate correlation coefficient has been suggested for predicting the ground vibrations in this study area.