Investigation of the causes of fly rocks :

Abstract

Fly rock are mainly rocks that are propelled beyond the blast area by the force of an explosion. Comprising of hard soil or stones from the exploding blast holes. When the uncontrolled material fragments are thrown beyond the allowable limits, they result in human injuries, fatalities and structure damages. In most pits; including the intended direction of throw is horizontal. If too little confinement is provided in the horizontal direction the blast "blows out", causing fly rock to be thrown at a low angle above horizontal, in most open pit mines, any fly rock will be propelled by the relative amount of confinement in the lateral direction as compared to the vertical. The result of too much lateral confinement is the tendency for blow-outs in the vertical. direction- The blasting operations done in the quarry by contracted company (HM Company) by Totoro cement industry is the one of the greatest causes of fly rocks in the quality since blasting has unavoidable mainly due to the increasing demand for blasted outputs like aggregates for civil and construction purposes limestone for cement milking at the plants, making fly rock remain to be a serious threat to both surrounding community, quarry personnel and the environment This project encompassed detailed assessment of geological rock properties for both structural and rock properties that had great influence to the study investigations, rock characterization for different geo-mechanicals rock properties and blasting techniques parameters that are being .in the quarry; their potential impacts to both blasting results and fly rocks were identified, discussed in the- report including the rock laboratory tests that were carried out. in the characterization and quantifying of rock samples. The rock powder factor used in the blasting operations, the rock fissures, fractures, joints, weathering extent, orientations of the different parameters and the rock discontinuities have been identified, and discussed in great details, And finally, by the end of this study. the causes of fly rocks in the Tororo limestone quarry have been investigated and achieved.