The Ingenieur Vol. 65 Water Power | Page 12

INGENIEUR concrete structures especially the plastic concrete cut-off wall and cement grout curtain. Questions were raised on the allowable limits of vibration caused by quarry operation and the potential impact on the dam under construction. The blasting design of Weng Lee quarry allowed maximum instantaneous charge up to 640 kg. Based on the method of analysis in Canada (Report on Blasting Impact Assessment for Nelson Quarry Extension, April 2006), the peak particle velocit y (PP V ) generated from the existing quarry was estimated to be 58.5 mm/s and 17.4 mm/s for buffer distance of 200m and 500m. Both DOE Guideline (2007) and United States Office of Surface Mining recommend the safe limit for the peak particle velocity of 12 mm/s. A minimum buffer 500m is required in order to meet the safe limit of PPV. The resolution of the quarry issu