CONTROL MEASURES AND SAFETY PRACTISES USED FOR FLY ROCK ISSUES IN MINING DUE TO BLASTING

Abstract

Blasting involves the breaking of rocks using explosive that rapidly change due to chemical reaction forming huge volumes of gases with high pressure and temperature causing kinetic energy. The blasting process is primarily a rock–explosive interaction that entails application of pressure generated by detonation of explosives, on rock mass, over a few milliseconds. This rock–explosive interaction results in rock breakage and heaving of the broken rock mass (muck). In comparison to the mechanical methods that rely predominantly on the compressive breakage, blasting exploits the tensile strength of the rock mass. This is probably the reason that blasting is still the most prevalent and economical method for rock breakage. Blasting, in general, results in ‘desired’ and ‘undesired’ outcomes that may be ‘regular’ or ‘random’ in nature. Any mismatch between the energy available and the work done will increase the adverse or undesired blast results like excessive throw and fly rock. Fly rock and excessive throw occur due to deviations in blast design execution, use of excessive explosive energy than the required levels to fragment and throw the rock mass, and/or presence of rock mass features, not accounted for during blasting