Guidelines for orepass design in a sublevel cave mine

Authors: Bunker, KA; Campbell, AD; O’Toole, D; Penney, A Download Paper

DOI https://doi.org/10.36487/ACG_rep/1511_37_Bunker

Cite As:
Bunker, KA, Campbell, AD, O’Toole, D & Penney, A 2015, 'Guidelines for orepass design in a sublevel cave mine', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 585-600, https://doi.org/10.36487/ACG_rep/1511_37_Bunker



Abstract:
Underground mines commonly use orepass systems as a safe and economic method to transport broken rock between levels. Although these systems are an integral part of such operations, design methodologies are generally limited to empirical methods, rules of thumb and limited case studies. This paper details orepass design issues in an operating sublevel cave (SLC) mine and the method used to determine suitable design parameters for future orepasses at the mine. The guidelines, as well as the system used to determine the parameters, can be used as a design methodology applicable to any other mine at a planning or operational stage. Operational issues during early orepass operation included hangups due to cohesive arching and ore compaction, and higher than forecasted wear rates. The operational and financial implications of these issues have necessitated the need to develop site based guidelines for orepass design and layout. Laboratory testing and statistical analysis were conducted in conjunction with empirical methods to determine optimum orepass diameter, inclination angle, pass length and tipping methodology. Wear rates have been measured for different tipping methods and used to provide an estimate for orepass longevity. Forecast wear rates for planned throughput have then been analysed to calculate maximum stable pass dimensions. Numerical modelling was utilised to determine suitable standoff distances between other orepasses, development and the SLC footprint. Regular monitoring was used to calibrate theoretical wear rates with actual measurements. This paper outlines how orepass design guidelines have been developed for the Ernest Henry SLC. Empirical methods and numerical analyse have been undertaken to determine guidelines which have been progressively calibrated using monitoring data and field observations.

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