Flyrock generation in limestone auarries.
Kopp-JW; Cumerlato-CL; Fletcher-LR
Proceedings of the Midwest Mine Health and Safety Conference, Marion, Illinois, July 22-23, 1992. Thomasson EM, Evers JO, eds., Carbondale, IL: Southern Illinois University at Carbonale, 1992 Jul; :7-16
The Bureau of Mines has been studying burden movement from blasting at several limestone quarries in eastern Wisconsin. To date, 17 blasts have been studied at 9 different sites using high-speed cinematography. All blasting was done with 3-in diameter holes using a variety of explosives. One design was modified to cause flyrock generation. Films from each blast were analyzed to show burden, and flyrock velocities, maximum flyrock distance, and direction of throw in relation to the shot and site conditions. This technique, in some cases, allowed determining point of origin and cause of the flyrock, as well as, the flyrock range. The behavior of the burden and flyrock was compared to the site geology as well as blast design parameters. Important parameters affecting the generation of flyrock were found to be stemming height, burden relief, and delay timing. Other important parameters identified in this study were site specific variations in geology and rock conditions such as overbreak from previous blasting. Flyrock came from the face and the hole collar region of observed shots. One shot threw rock over 500 feet in all directions from the blast.
Mining-industry; Quarries; Safety-research; Injury-prevention; Geology; Stone-mines
Proceedings of the Midwest Mine Health and Safety Conference, Marion, Illinois, July 22-23, 1992