Developments in blast fragmentation measurement
Conference
·
OSTI ID:398361
- Franklin Geotechnical Ltd., Orangeville, Ontario (Canada)
- Univ. of Waterloo, Ontario (Canada)
The digital image analysis program WipFrag has been developed under contract to INCO for use in quality control of underground blasting operations. This paper outlines the relevance of fragmentation to underground mining, the hardware and photography requirements, and key features and operating principles of the software. The science of granulometry offers a wide choice of statistics relating to the size and shape of fragments and the fabric and geometry of the rockpile. From these the authors have chosen to represent size distribution by the mass median diameter and the Rosin-Rammler coefficients. Fragment shape is measured by practical sphericity, a useful index to the slabbiness of the rock, which is often a factor in increased costs for loading, transportation and crushing. Concepts of resolution and accuracy are reviewed as they apply to digital image analysis systems. A method of calibration is described, using sieved crushed rock standards that simulate a range of rockpile uniformity conditions. Alternative zoom-merge procedures that combine images at various scales of magnification are expected to replace the empirical methods. Further research into blast optimization will require quantification of the triangular relationship between rock quality, blast parameters, and fragmentation statistics. Any one of these can be predicted knowing the other two, thus suggesting a new approach to measurement of rock mass quality. Routine fragmentation measurements might therefore give early warning of the need for modifications in stope spans, pit wall angles, and ground reinforcement and stabilization systems. Applications to measurement of rockfalls and rockbursts are also proposed.
- OSTI ID:
- 398361
- Report Number(s):
- CONF-9502142--
- Country of Publication:
- United States
- Language:
- English
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