Application of ground vibration frequency spectrum analysis as a tool for optimizing the blast design in large open pit mines
- Visvesvaraya Regional Coll. of Engineering, Nagpur (India). Dept. of Mining Engineering
This paper explains the methodology for assessing the efficiency of rockmass fragmentation by explosive blasting, from ground vibration frequency spectrum analysis of the blast event. Explosives are used in the mining, quarrying and construction industries for fragmenting rockmass to a suitable size. When an explosive charge is detonated, in addition to fragmenting the rockmass, it will also generate ground vibration and air vibrations. Efficiency of a blast depend upon percentage of blast energy wasted in generating ground vibrations and air vibrations. This in turn will depend upon rockmass characteristics, amount of explosive energy used per delay and spatial distribution of explosive in the rockmass. Ground vibrations and air vibrations, arising out of explosive detonation in a rockmass, could be captured by micro-computer based engineering seismograph and sound level meter. Typical frequency range indicative of efficient rockmass fragmentation for a particular rockmass can be identified from ground vibration frequency spectra analysis of the blast event on a personal computer applying Fast Fourier transforms (FFT). The typical frequency range indicative of efficient rockmass fragmentation depends upon rockmass impedance and can be estimated from rockmass characteristics and monitoring few trial blasts. Blast event efficiency is estimated by comparing the typical frequency range with the dominant frequency range of the blast event record. A large number of blast events monitored and analyzed by the author in different rockmass formations and correlation of the results with observations made while fragmented material is lifted and loaded into trucks indicated that ground vibration frequency spectrum analysis could be used as a reliable and cost effective tool for assessing the blasting efficiency and optimizing blast design in large open-pit mines.
- OSTI ID:
- 398335
- Report Number(s):
- CONF-9401127-; TRN: IM9649%%543
- Resource Relation:
- Conference: 10. annual symposium on explosives and blasting research, Austin, TX (United States), 30 Jan 1994 - 30 Jan 1996; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the tenth annual symposium on explosives and blasting research; PB: 313 p.
- Country of Publication:
- United States
- Language:
- English
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