Application of digital image analysis technique for fragmentation assessment and blast optimisation

Application of digital image analysis technique for assessment of blast fragmentation is gaining grounds in India, very recently. Central Mining Research Institute, India made its maiden attempt to optimize blast design based on fragmentation assessment of one of the biggest opencast mines of Singareni Collieries Company Limited, India. Indigenously developed photoanalysis software called 'FRAGALYST' was used for measurement of blast fragmentation A series of trial blasts were carried out in overburden benches with ongoing blast parameters and pictures of muck pile were taken by video camera for image analysis. Cycle time study of loaders and dumpers was done to determine machinery performance for each and every blast. Optimization of pre-blast parameters like specific charge, specific drilling and post-blast results like shovel cycle time and dumper cycle time, was done to determine optimum range of fragmentation. Interpreting the mean fragment size (K50) obtained by image analysis the blast design parameters were modified. The modified blast design worked out well in the field and resulted in desired optimum fragmentation. Blast results in terms of shovel cycle time and dumper cycle time were measured for the practical validation of optimization technique. It is finally noticed that the application of image analysis software for assessment of blast fragmentation resulted in substantial improvement of productivity of opencast blasting and allied operations. This paper outlines various steps and procedures involved in application of the image analysis technique.