Application of digital image analysis technique for assessment of blast fragmentation and explosives energy utilisation in a large opencast coal mine

摘要

A good and optimum fragmentation is one of the primary criteria of blasting in mines. This governs other unit operations like loading, transportation and thus the total cost of mining. Many rock mass parameters as well as blast design parameters control the fragmentation. Models have been developed to predict mean fragmentation and uniformity including the influencing parameters. Digital image analysis technique with analytical software is one of the latest and easy to use tools to measure the fragmentation in large muck piles. Fragalyst software has been extensively used in PK-OCII mine of SCCL to assess the fragmentation distribution and energy utilisation in 21 blasts. It was revealed that though the maximum size of the fragments hardly exceeded the permissible one, the mean fragment size was predominantly out of the optimum range inviting modifications in the blast design. Further, the explosives energy utilisations assessed in different blasts could be well related with the pre- and post-blast fragmentation.