Adiyansyah, B, Abzhanov, A, Chapman, D, Bar, N, Caratti, J & Cebrian, B 2023, 'Improvement of blasting practices to minimise wall damage at Bozshakol copper mine', in PM Dight (ed.), SSIM 2023: Third International Slope Stability in Mining Conference
, Australian Centre for Geomechanics, Perth, pp. 595-616, https://doi.org/10.36487/ACG_repo/2335_39
Wall damage in large open pit mines is often induced by adjacent blasting activities as a consequence of improper blast design considerations on unforeseen geotechnical conditions. Post-blast damage may vary from slight to severe levels, which are represented by the presence of tension cracks to significant back-break causing crest deterioration or, even worse, loss of the berm itself. Wall control blasting practice is essential in minimising the effect of wall damage so as to reduce geotechnical risks related to rockfall potential, single to multi-bench stability and, less frequently, overall pit wall stability. On some occasions, associated risks may have the potential to impact on critical mine infrastructure such as long-term haulage ramps. Significant economic costs are associated with remediation works required to mitigate rockfall risks, which may range from support measures for rockfall containment to mine design changes and deviations from the mine schedule that typically result in either additional waste removal and ore deferral or sterilisation.
This paper discusses the improvement of wall control blasting practices at Bozshakol open pit mine, located in Kazakhstan, Central Asia. It particularly focuses on trim blasting and pre-splitting to minimise wall damage by considering the effects of vibration and blast energy factors within various geotechnical domains. Input of geotechnical information including rock mass characteristics and geological structures also plays an important role for proper wall control blast design considerations. Vibration monitoring is also carried out to assess ground vibration levels expressed by peak particle velocity and establishing site-specific correlations for recommending maximum charge weight per delay.
Despite prioritising for wall protection purposes, blasting also needs to achieve a level of fragmentation that supports efficient and productive mining rates. With collaborative interdisciplinary efforts, it is expected that fragmentation needs will be met while achieving final wall design within the tolerance of toe-crest position, bench face angle and berm width while minimising wall disturbance so as to provide a more reliable mine plan.
Keywords: wall control, blasting, blast design, blast vibration, vibration monitoring
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