Risk based prediction of safe charge per delay in surface mine blasting—A new approach

摘要

In view of expanded habitation, conservation and demand for minerals, surface mine blasting is nowadays conducted very close to structures. The safe blast-induced ground vibration criteria to avoid struc-tural damage have been decided in different countries for different ranges of frequency; and the safe vibration is recommended for that range of frequency which has maximum population in the total array. To maintain the recommended safe vibration level, the safe maximum charge per delay is estimated using the USBM proposed square root scaled distance predictive model. Confidence levels are further incorporated in the prediction mod-els to improve the safety in critical areas. However, this safe approach leads to estimation of the permissible charge per delay at times at a very low value, adversely influencing the blast performance. A new risk-based approach for recommending higher safe vibration levels is discussed in this paper to provide an option for using a greater explosives charge per delay leading to larger blast rounds.