The hazards of suace blasting are primarily due to lack of blast area security, flyrock, premature blast, and misfire (Verakis & Lobb, 2001). Blasting generally entails two purposes:
rock fragmentation and displacement of the broken rock. The displacement of the broken rock depends on the shot-design parameters, geological conditions, and mining constraints. Fragmented rock is not expected to travel beyond the limits of the blast area. The blaster determines the bounds of the blast area and is responsible for complying with safety laws. Langefors & Kishlstrom (1963), Roth (1979), and Persson et al. (1994) have developed theories to compute flyrock range. A blaster may use such concepts, in conjunction with past experience, to determine the size of a blast area. The Institute of Makers of Explosives (IME) defines flyrock as the rock propelled beyond the blast area by the force of an explosion (IME, 1997). An injury due to flyrock is sustained when it travels beyond the blast area and injures someone. The major factors responsible for flyrock are insufficient burden, improper blasthole layout and loading, anomaly in the geology and rock structure, insufficient stemming, and inadequate firing delays. Injuries due to lack of blast area security are caused by failure to use proper blasting shelter, poor communications, and inadequate guarding of the blast area (Rehak et al., 2001).
by T. S. Bajpayee, T. R. Rehak, G. L. Mowrey, and D. K. Ingram
source picture : http://mining.mosaicprojects.net/images/millward_blasting.gif
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