Issues with transitioning from open pits to underground caving mines

Authors: Ross, IT; Stewart, CA

Open access courtesy of:

This paper is hosted with the kind permission of the Universidad de Chile, Eighth International Conference & Exhibition on Mass Mining, 2020.


DOI https://doi.org/10.36487/ACG_repo/2063_11

Cite As:
Ross, IT & Stewart, CA 2020, 'Issues with transitioning from open pits to underground caving mines', in R Castro, F Báez & K Suzuki (eds), MassMin 2020: Proceedings of the Eighth International Conference & Exhibition on Mass Mining, University of Chile, Santiago, pp. 221-238, https://doi.org/10.36487/ACG_repo/2063_11

Download citation as:   ris   bibtex   endnote   text   Zotero


Abstract:
This paper covers the issues and trends associated with transitioning from an open pit operation to an underground caving mine. The decisions made on the timing of the transition affect many parameters including the Mineral Resources (Resources) and Ore Reserves (Reserves), the timing and costs associated with the studies required to support the change. Fundamental issues such as the size of the underground operation and the anticipated ramp-up are discussed as well as the options afforded by Hybrid Caves (a Sub-Level Cave (SLC) later converting to a Block or Panel Cave (BC, PC)). The economics and risks of these strategies are discussed as well as the resultant impacts on traditional financial metrics. The authors believe that an holistic approach to evaluating the transition from open pit to underground is required, not simply an open pit optimisation, followed by a transition to an underground mine. Operations generally do not allow sufficient time, or plan the pre-requisite drilling programmes early enough, to make properly informed decisions about the transition.

References:
Aguayo, A, Uribe, G, & Pedrero, J 2012, ‘Multi-lifts Production scheduling at the Chuquicamata Underground project’, in MassMin 2012, Sudbury, Ontario, Canada. CIM.
Campbell, AD, Ah Mu, E & Lilley, CR 2016, ‘Cave Propagation and Open Pit Interaction at the Earnest Henry Mine’, in C Carr & G Chitombo (eds), Proceedings of MassMin 2016, The Australasian Institute of Mining and Metallurgy, 2016, pp. 311-318.
Chung, J, Topal, E & Ghosh, AK 2016, ‘Where to make the transition from open-pit to underground? Using integer programming’, J. S. Afr. Inst. Min. Metall. vol.116 n.8 Johannesburg Aug. 2016. pp. 801-808.
Dunstan, G 2016, ‘The Truth is stranger than Fiction – the Story of Ridgeway Gold Mine’, in C Carr & G Chitombo (eds), Proceedings of MassMin 2016, The Australasian Institute of Mining and Metallurgy, 2016, pp. 19-30.
Dyas, KE 2002, ‘Project Evaluation’, SME Mining Reference Handbook (ed. Lowrie, RL), Society for Mining Metallurgy and Exploration (SME) 2002. ISBN 0873351754, 9780873351751.
Fitzgerald, B 2019, ‘Rio Tinto wake-up call’, www.mining-journal.com/research/news/1367724/, [19/07/2019].
Flores, G & Catalan, A 2019, ‘A transition from a large open pit into a novel “macroblock variant” block caving geometry at Chuquicamata mine, Codelco Chile, in J. Rock Mechanics and Geotechnical Engineering, vol.11, no. 3, June 2019. pp. 549-561.
Fuentes, S 2004, ‘Going to an underground (UG) mining method’, Proceedings MassMin 2004, Santiago, Chile pp. 633-635.
Gantamur, J, Godard, R, Prince, F and Pascoe, C 2016, ‘Development and evaluation processes of cave production schedules for the Resolution Copper project’, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), The Australasian Institute of Mining and Metallurgy, 2016, pp. 59-64.
Hall, B 2014, ‘Cut-off Grades and Optimising the Strategic Mine Plan’, Spectrum Series 20, The Australasian Institute of Mining and Metallurgy, Melbourne, p. 300
Jakubec, J, Woodward, R, Boggis, B, Clark, L & Lewis, P 2017, ‘Underground mining at Ekati and Diavik Diamond Mines’, 11th International Kimberlite Conference, Botswana, 2017.
Jakubec, J, Lagace, D, Boggis, B, Clark, LM & Lewis, PA 2018, ‘Underground mining at Ekati and Diavik diamond mines’, in Proceedings of the Fourth International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, ed. Y Potvin & J Jakubec, Australian Centre for Geomechanics. pp. 73-88.
Lett, JL, Brunton, I, Capes, GW, Jager, A, Mobilio, B, Rachocki, J, Sharrock, GB & Secheny, M 2016, ‘Undercutting to Surface Breakthrough – Cadia East Panel Cave (Stage 1)’, in C Carr & G Chitombo (eds), Proceedings of MassMin 2016, The Australasian Institute of Mining and Metallurgy, 2016, pp. 65-81.
Manca, L & Dustan, G 2008, ‘Planning the transition from SLC to block caving operations at Ridgeway gold mine’, in H. Schunnesson & E Norlund (eds), Proceedings of MassMin 2008, pp. 401-12.
McCarthy, P 2010, ‘Setting plant capacity’, Transactions of the Institutions of Mining and Metallurgy, Mineral Processing and Extractive Metallurgy, vol.119, no. 4,C184–C190.
Mining Journal, 2019, ‘Rio Tinto takes Bingham southern pit spend out to US$2.5B’, Available from: <www.mining-journal.com/copper-news/news/1337062>. [03/12/2019].
Mining Technology 2019, ‘Finsch Diamond Mine, Northern Cape’, Available from <>. [02/03/2019]
Morrison, B 2017, ‘The Project Management Triangle – Time, Quality, Cost – you can have any two’. Available from: < >. [02/03/2020].
OZ Minerals 2019a, ‘Carrapateena Block Cave Expansion has potential to optimise value and further unlock the province’, ASX Release, 6th March 2019, Available from: < > [02/03/2020]
OZ Minerals 2019b, ‘Carrapateena 2019 Mineral Resource and Ore Reserves Statement and Explanatory Notes as at 30 June 2019’, Available from: <>. [02/03/2020]
Ross, B 2016 ‘Rise to the occasion – Lessons from the Bingham Canyon Manefay slide’, Society for Mining Metallurgy and Exploration, electronic edition published 2017, ISBN 987-0-87335-431-8.
Ross, IT 2014, ‘Transition from Open Pit to Underground Mining’, in Mineral Resource and Ore Reserve Estimation – The AUSIMM Guide to Good Practice, 2nd Edition, pp. 409-414 (The Australasian Institute of Mining and Metallurgy: Melbourne, Australia).
Ross, IT and deWolfe, V 2016, ’Supercaves – Benefits, Considerations and Risks’, in Proceedings, 7th International Conference on Mass Mining, MassMin 2016, pp. 51-58, (The Australasian Institute of Mining and Metallurgy: Melbourne, Australia).
Sainsbury, DP, Sainsbury, BL, Paezold, H-D, Lourens, P, & Vakili, A 2016, ‘Caving-induced Subsidence Behaviour of Lift 1 at the Palabora Block Cave Mine’, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), The Australasian Institute of Mining and Metallurgy, 2016, pp. 415-426.
Severin, J, Eberhardt, E & Woo, KS, 2010, ‘Influence of major fault zones on 3D ground deformations caused by open pit block cave interactions’, in Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, ed. Y Potvin, Australian Centre for Geomechanics. pp. 455-468.
Stacey, TR & Terbrugge, PJ 2000 ‘Open pit to underground – transition and interaction’, Proceedings MassMin 2000, Brisbane, Australia, pp. 97-104. (The Australasian Institute of Mining and Metallurgy: Melbourne, Australia).
Stewart, CA, Allman, A & Hall, B 2010, ‘Block cave optimisation – a value driven approach’, in Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, ed. Y Potvin, Australian Centre for Geomechanics. pp. 219-230.
Stewart, CA & Butcher, R 2016, ‘Block Cave Evaluation’, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), The Australasian Institute of Mining and Metallurgy, 2016, pp. 809-816.
Tyler, D, Campbell, A & Heywood, S 2004, ‘Development and measurement of the subsidence zone associated with SLC mining operations at Perseverance – WMC, Leinster Nickel Operations’, in A Karzulovic & M Alfaro (eds), Proceedings of MassMin 2004, Santiago, Chile, pp. 519-525.
Tukker, H, Holder, A, Swarts, B, van Strijp, T & Grobler, E 2016, ‘The C CUT block cave design for Cullinan Diamond Mine’ J. S. Afr. Inst. Min. Metall. [online]. 2016, vol. 116, no. 8, pp. 715-722.
Van As, A 2014, ‘Collection of Geotechnical Data from Drillholes’, in Mineral Resource and Ore Reserve Estimation – The AUSIMM Guide to Good Practice, 2nd Edition, pp. 109-120 (The Australasian Institute of Mining and Metallurgy: Melbourne, Australia).
Vyazmensky, A, Elmo, D, Stead, D & Rance, J 2008, ‘Numerical analysis of the influence of geological structures on the development of surface subsidence associated with block caving mining’, in H Schunnesson & E Norlund (eds), Proceedings of MassMin 2008, pp. 857-866.
Wellman, EC, Nicholas, DE & Brannon, CA 2008, ‘Geomechanics considerations in the Grasberg pit to block cave’, in H Schunnesson & E Norlund (eds), Proceedings of MassMin 2008, pp. 413-422.
Wellman, EC, Killian, JR, Brannon, C, & Ross, I 2012, ‘Grasberg Block Cave: drawpoint opening and production block sequencing’, in MassMin 2012, Sudbury, Ontario, Canada. CIM.
Whittle, D, Brazil, M, Grossman, PA, Rubinstein, JH, & Thomas, DA 2016, ‘Determining the Open Pit to Underground Transition – a New Method’, in C Carr & G Chitombo (eds), Proceedings of MassMin 2016, The Australasian Institute of Mining and Metallurgy, 2016, pp. 731-741.




© Copyright 2024, Australian Centre for Geomechanics (ACG), The University of Western Australia. All rights reserved.
View copyright/legal information
Please direct any queries or error reports to repository-acg@uwa.edu.au