Paredes, P, Leano, T & Jauriat, L 2018, 'Chuquicamata underground mine design: the simplification of the ore handling system of Lift 1', in Y Potvin & J Jakubec (eds), Proceedings of the Fourth International Symposium on Block and Sublevel Caving
, Australian Centre for Geomechanics, Perth, pp. 385-398.
The ore handling system layout plays a fundamental role in cave mining projects, not only because it is one of the main drivers in the production capacity and reliability of the mining system, but also because it is a fundamental variable in the footprint’s development time and cost (Paredes et al. 2016).
In terms of ore handling system definition, the governing paradigm in Codelco’s projects has been the productivity maximisation through the optimisation of load–haul–dump unit (LHD) tramming distances. This has resulted in layout designs that solve the productive-effectiveness problem by shortening the LHD tramming distance by introducing orepasses inside the footprint area.
Following this principle, the original macro block design of the Chuquicamata Underground Mine Project (PMCHS) considered an ore handling system layout based on the maximisation of operational flexibility. In this design, LHDs dumped into orepasses located inside the footprint area, transferring the ore into crusher chambers located below the production level, where ore was crushed and then conveyed to surface. This resulted in a very flexible layout for the operation, but at the same time, implied the execution of a large amount of vertical and major infrastructure excavations, as well as the assembling, commissioning and operation of a large amount of mechanical equipment for the mine.
The caving industry today has proven the effectiveness of simpler layouts based on direct tipping by LHDs to crushers positioned in the periphery of the footprint. The productivity competitiveness of these type of layouts is based on the use of intensive preconditioning and larger LHD and crushing equipment (Manca 2013; Flores 2014; Paredes et al. 2016).
A first approach in improving Chuquicamata’s mine design with a simpler mine layout was performed in 2015 (Paredes et al. 2016), but for a limited experimental area. Then, during 2017, in order to improve the whole project’s economics by reducing development time and cost (with a simpler mine design), and in parallel with the development of the initial macro blocks, the PMCHS ore handling system for Lift 1 was reengineered, aiming to capture the latest improvements in existing technology, such as the application of large-scale rock mass engineering, with higher capacity loaders and crushers able to process larger sized boulders tipped directly from large bucket loaders. This paper presents the main considerations and results for the transition from a traditional LHD–orepass layout to a LHD–peripheral crusher-based layout.
Keywords: mine design, ore handling system, block caving, caving projects
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