Mikula, P & Gebremedhin, B 2017, 'Empirical selection of ground support for dynamic conditions using charting of support performance at Hamlet mine', in J Wesseloo (ed.), Deep Mining 2017: Proceedings of the Eighth International Conference on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 625-636, https://doi.org/10.36487/ACG_rep/1704_42_Mikula
This paper demonstrates assessment of ground support dynamic performance, using charting of easily available mine site data, to provide guidance for support selection for dynamic conditions. The process is transparent and accessible to site engineers, and is described for the Hamlet gold mine in Australia. The process defines the relationships between three factors: the seismic event magnitude, the level of damage caused, and the installed ground support. The process is firmly based on the recorded history of these three factors at the mine.
Site geotechnical engineers need a simple yet defensible support selection method for seismic conditions that can be used with confidence. The aim is to enable selection of the appropriate ground support according to the expected or forecast level of seismic hazard. Empirical charting represents one way of bracketing the performance of particular ground support schemes in dynamic conditions. It assesses the past performance of the installed ground support, to provide guidelines for forward selection of support.
This approach has limitations and uncertainties which add to the scatter of the data points in the charts. However, the approach has the advantages of including the actual installed bolts, seismic events, site geology and support performance, making the results calibrated to, and applicable to, the mine. It also benefits by not requiring estimation of quantities, including the ground motion (peak particle velocity) at the location of a support element, the site effect, and the energy and load capacities of those elements during dynamic disturbances.
The empirical charts are not transferable between mine sites. It is hoped that the description of the methodology in this paper will encourage engineers to explore similar work for their sites, and gain better understanding of the in situ performance of their ground support under dynamic conditions.
Keywords: ground support system, dynamic, support selection, support performance, seismicity, empirical, mining
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