Application of digital image analysis for monitoring the behavior of factors that control the rock fragmentation in opencast bench blasting: A case study conducted over four opencast coal mines of the Talcher Coalfields, India

Abstract

Drilling and blasting play a very important role in driving the economy of opencast mines, as various mining activities related to strata handling are dependent on the size of the rock mass created due to blasting. Thus the analysis of fragments created from rock explosion is essential in order to monitor its compatibility with the deployed mining machineries/HEMMs (such as shovel, dumper, dragline, etc.). As over fragmentation as well as under fragmentation both tend to increase the cost of mining, the generation of fragment size in the desired range is necessary. Several factors control the rock fragmentation in blasting, such as the burden, bench height/ drilling depth, stemming column, powder factor and hole diameter. The assessment of rock fragmentation with respect to the aforementioned parameters helps to enhance the blast performance and, hence, this study intends to carry out digital image analysis for monitoring the mean fragment size and boulder percentage. A highly consistent result has been obtained using forty blasting datasets carried out in the four different opencast mines of the Talcher Coalfield (India), namely Balram OCP, Ananta OCP, Lakhanpur OCP, and Lajkura OCP.