Fragment size distribution in blasting

Abstract

It is well known that rock is generally treated as a heterogeneous material and the heterogeneity of rock causes sizes distribution of fragmented rocks in blasting. This paper discusses experimental and numerical rock fragment size distribution. To evaluate fines in bench blasting, two test experiments were conducted in the field and fragment sizes of blasted rocks were estimated by sieving analysis and image analysis. The fragment size distributions by image analysis were corrected with the evaluation of the fines. To predict rock fragmentation in bench blasting, a numerical simulation method was developed. Fragment development in bench blasting has been modeled by the numerical simulation method and analyzed for fragment size distributions by image analysis program. The fragment size distributions were corrected with the evaluation of fines, which correspond to compressive fracture zone around a blast hole. This paper discusses the importance of correct evaluation of the fines in bench-blasted rock and shows the possibilities of realistic prediction of fragmentation using a numerical simulation method and image analysis.