Harmonizing Blasting Efficiency: A Case Study on Evaluation and Optimization of Fragmentation Size and Ground Vibration

Abstract

Drilling and blasting techniques persist as the most economically viable approaches for rock excavation in both surface and underground mining. However, the conventional focus has predominantly cantered on optimizing rock fragmentation, often overlooking the consequential impacts of by-products, such as ground vibration and fly rock. The core objective, which is not entirely met by the current utilization of explosive energy for rock mass breakage, reveals that a mere 20–30% of the explosive energy effectively contributes to shattering the rock mass. The remaining percentage is dissipated as ground vibration, air blast, noise, fly rock, back breaks, and other ancillary effects. This investigative endeavor involved a comprehensive examination of an operational mine, incorporating a series of blast exercises to systematically evaluate the impact of various blast design parameters, including burden, spacing, stemming length, bench height, powder factor, explosive quantity, and maximum charge/delay. For the interpretation and analysis of results, sophisticated software and instrument such as Wipfrag and Minimate Plus seismograph were employed. The unveiled findings indicate that specific blast design parameters, such as a burden of 4 m, spacing of 5 m, stemming length of 5 m, bench height of 6 m, powder factor of 2.25 te/kg, and maximum charge/delay between 55 and 60 kg, were instrumental in yielding favorable blasting outcomes. These parameters led to mean fragmentation sizes below 100 mm and peak particle velocities below 10 mm/s, thereby highlighting the potential for enhanced efficiency in rock excavation through meticulous blast design considerations.