The effects of rock mass characteristics on fragmentation in controlled blasting experiments in small development headings
- McGill Univ., Montreal, Quebec (Canada). Dept. of Mining and Metallurgical Engineering
- Golder Associates, Sudbury, Ontario (Canada)
- CANMET, Val d`Or, Quebec (Canada)
A joint Federal Government-Industry research project on the effect of geology on the fragmentation of rock excavated by blasting in underground developments was conducted at the CANMET Experimental Mine, near Val d`Or, Quebec. A total of thirteen (13) blasts were studied from November 1994 to February 1995. The analysis of each blast was divided into three stages: pre-blast characterization, including structural mapping, assessment of Rock Mass Ratings (RMR), Tunneling Quality Indices (Q), blast design documentation; blast characterization comprising blast vibration monitoring and analysis; and post-blast assessment comprising fragmentation assessment by digital photoanalysis, calculation of half cast factors and measurements of bootlegs. The blast design was kept as constant as possible throughout the study in order to limit the variation of parameters to the geology-related ones. The results were analyzed to determine any correlation between the rockmass characteristics and the blast results. General trends confirmed basic blasting principles but other results were somewhat unexpected. The rock types encountered have very similar mechanical properties and the quality of the rockmasses did not vary extensively. Therefore, any variance in the results is best explained by the blast performance itself. Comprehensive blast vibration monitoring data can be used for studies relating explosive energy transmitted to the rock, to the degree of fragmentation or wall control. Similar studies in different geological environments are needed to compare with the results gathered in this study in order to better understand the influence of geology on blast fragmentation.
- Sponsoring Organization:
- Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada)
- OSTI ID:
- 433569
- Report Number(s):
- CONF-960262--
- Country of Publication:
- United States
- Language:
- English
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