Blasting of rock results in its fragmentation. Fragmentation is the end result of blasting. Optimum fragmentation is desirable which results in higher productivity, less wear and tear of loading equipment and hence less maintenance of equipment and plant. Degree of fragmentation has direct impact on production costs and so on the mine profits. Fragmentation size assessment for a blast is a prerequisite to know the blast efficacy in case of production blasting. Blast economics proves the importance of the size assessment of fragmentation. The methods for measurement of fragmentation passed through the evolutionary stages from physical sieving to the online photo-analysis. Considering the Indian geo-mining conditions, the study was confined to compare the state-of-the-art of fragmentation assessment in opencast mines and its utility for improved productivity. Basically, the study was done into two phases. In first phase, various mines were visited their present state-of-the-art of fragmentation assessment was studied. One hundred and twenty-six blasting engineers were circulated the questionnaires to get the first hand information about the present fragmentation assessment method adopted in their mines and data were collected. In second phase, several experimental blasts were conducted at various mines and in each blast fragmentations were measured by conventional and advanced size analysis technique and results were verified. A self-developed semi-mechanized image analysis setup was developed in the laboratory. A very practical approach was adopted so as to make the results useful for blasting engineers. The study revealed that Indian mining industry needs adoption of precise and result oriented fragmentation size assessment, which can befit into production environment. Considering the Indian geo-mining conditions and productive environment, image analysis is an accurate, reliable and practical method.
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