The economy profits from the rock excavated in mines and quarries and the excavations required for theconstruction of roads and buildings. However such excavations are achieved by blasting withexplosives, and explosions create fly rock and vibrations which in some cases may throw rock far intoinhabited regions and may vibrate buildings excessively in these regions. Society, however, no longeraccepts that their quality of life be disturbed by the risks of fly rock or the perturbation of vibrations.Thus it is important to know how to design blasts that do not cause excessive fly rock or vibrations, andto understand why sometimes a blast does create excessive vibration or fly rock. An article presented atthe 2015 ISEE (reference 1) explains how unacceptable vibrations can be avoided, while the presentarticle explains why dangerous fly rock occurs and how it can be avoided. The article shows byrigorous calculations with the blast simulator Blaspa that long range fly rock can be due to short collaror short burden, but mainly it explains how inadequate blasting that allows the floor to rise can causeeven further reaching fly rock, a situation not usually recognized by most blasters.
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