Evaluation of blasting in an opencast mine

Abstract

Fragmentation is one of the key issues in opencast blasting as properties like shape and size of rock materials are very important information for production optimization. The degree of fragmentation influences the economy of the mining process and hence the fragmentation of blasted rock forms the basis to evaluate the quality of a blast. Digital image processing technique is the latest fragmentation analysis tool. This technique has recently been proved better than the conventional methods. Those methods are also time saving and offer accurate measurement.
Wipfrag is an image analysis system for measuring size distribution for blasted or crushed rock. It was developed by Wipware, Inc. Canada. It accepts images from a variety of sources such as roving cam coders, digital camera, photographs, or digital files. It uses automatic algorithms to identify individual fragments on the image, and measures the profile areas on the blocks. It reconstructs a three-dimensional distribution using geometric probability.
In this study, 10 images from a blasted chromite muck pile were analysed through WipFrag image analysis system. Both single and merged image analysis were done and the merged image analysis was used to evaluate optimum fragmentation. Mean fragmented size of the blasted rocks has been predicted from the analysis.