A simulation comparison of operating strategies for electrified block cave mines

Abstract

Block cave mining is a mining method aimed at achieving a high tonnage output from a single production level. Interactions between production loaders and consequent cycle delays can constrain overall production level performance. Together with access restrictions associated with the control of caving progression and secondary break requirements, these constraints can prevent block cave mines from reaching throughput targets. Careful layout design and development of operating strategies for the production level are critical for minimising equipment interactions and building an optimised block cave operation. In striving for a net zero emissions mining operation, many companies are actively investigating the option of electrification of their mining fleet. This adds another dimension to design considerations and creates new possibilities for block cave designs and operating strategies. The potential impacts for charging of battery electric vehicles requires consideration and ventilation limits on the practical number of production loaders are reduced, giving rise to different design solutions. This paper explores the capability of a number of alternative production level operating strategies for the Carrapateena mine, which an OZ Minerals owned, South Australian copper-gold mine, ramping up to a rate of 12 Mtpa from 2029 utilising the block cave mining method. A comparison of the performance characteristics for each alternative is assessed using a detailed simulation model of the block cave operations. Relationships betweenfleet size and production level throughput are developed for each alternative operational strategy to demonstrate relative performance over a target throughput range for the mine. The assessment demonstrates how alternative operating strategies can be used to alleviate production level bottlenecks and improve output for block cave mining operations. Outcomes from the case study are broadly applicable to other block cave operations, particularly those that will move to, or are being designed as an electric mining operation.