Mariager, S & Fargher, M 2024, 'Loop de Loop – An innovative block cave extraction level design for BC1 at Carrapateena', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 17-31, https://doi.org/10.36487/ACG_repo/2435_A-02
(https://papers.acg.uwa.edu.au/p/2435_A-02/)
Abstract: Block cave mining is a mining method aimed at achieving a high tonnage output from a single extraction level. Ensuring that production loaders can operate as efficiently as possible on this level is critical in achieving the planned tonnage output. Given the long-life span of block cave extraction levels, it is important the level is designed with the future in mind, in terms of allowances for enabling technology and future operating strategies.  

Other key considerations that are given to the design of a block cave extraction level are related to geotechnical considerations (pillars, impact of abutment zones), civil infrastructure (concrete roadways, drawpoint infrastructure, dewatering), ventilation infrastructure (doors, fans) among other things. Careful consideration to the layout of the extraction level is required to ensure all elements are allowed for in the design. 

This paper explores an innovative block cave extraction level design, which incorporates a loop philosophy for the operation of the level in steady state (all drawbells established and operational), while still providing the means to extract material using the conventional drawpoint to crusher approach. This design is being proposed as an option for Block Cave 1at BHP’s Carrapateena mine, located in the Gawler-Craton region of South Australia. At the cost of minor additional fleet requirement, the maximum potential output from an extraction level can be increased significantly on what was previously thought possible. Pending real world application, the loop design has the potential to create a paradigm shift in the thinking of how block cave extraction levels are designed and operated.