Heslop, TG 2010, 'Understanding the flow of caved ore and its influence on ore recoveries and dilution in a block cave', in Y Potvin (ed.), Caving 2010: Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 539-551, https://doi.org/10.36487/ACG_rep/1002_37_Heslop
(https://papers.acg.uwa.edu.au/p/1002_37_Heslop/)
Abstract: Ore recovery and dilution are critical issues in the economic projections of block cave viability and ultimately the profits made by the mine. In planning and operating caving mines, numerical modelling techniques are increasingly used to model material flows in the feasibility and planning phases of the mine life, and to monitor draw down in the production phase. Not only are numerical modelling results strongly influenced by the assumed boundary conditions and material flow characteristics, the modelling techniques have limitations and may not reliably replicate the actual conditions in the cave. These include variations in material flow characteristics and the changes in these as the draw progresses. Any errors or biases in these assumptions can have a huge effect on economic projections and ultimately in the actual profitability of the mine. A sound understanding of the dynamic nature of draw mechanics is essential in both the appraisal of modelling results and in the formulation of draw control strategies for maximum recoveries.

In this paper the writer reviews material flow theories, the factors that influence the nature and direction of draw and discusses strategies that could assist in reducing dilution ingress from both theoretical and practical points of view. Recent experience and lessons from producing mines, marker migration monitoring and model tests are drawn on for this assessment.