Authors: Mohanty, B; Zwaan, D; Trivino, L


Cite As:
Mohanty, B, Zwaan, D & Trivino, L 2014, 'Investigation of stope blast designs in a deep underground mine through vibration analysis', in M Hudyma & Y Potvin (eds), Proceedings of the Seventh International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 525-532.

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Abstract:
A comprehensive blast monitoring program was carried out in multiple stopes at depths between 2,000 and 2,350 m levels in a deep underground copper–nickel mine. The diagnostic tools employed were multi-station high frequency (>10 kHz) and high-g (50-100 g) triaxial accelerometers, at distances ranging from 10 to 50 m from the blasts. A total of over 30 production blasts were monitored in both low-stress and high-stress stopes, with the objective of determining the energy release characteristics of both single and multiple deck blasts, and identify the degree of malfunction if any in explosive energy release as indicated by the resulting blasting vibrations at these deep levels, and specific to each blast design. Packaged water-gel explosives with an average charge weight of 35 kg/deck were employed in 162 mm diameter boreholes in these fan-drilled blasts. Analysis showed that only ~30% of the explosive decks yielded acceptable levels of energy (40-100% of the expected levels), whereas an equal number either failed or yielded <40% of the expected vibration energy. It points to an unacceptable level of blast malfunctions, which would adversely affect dilution control and overall productivity. The various possible causes of these malfunctions have been discussed and remedial measures proposed to overcome these problems.

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