Challenges encountered in high-lift block cave extensions and the lessons learned: experience from the Padcal Mine, Philippines
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Authors: Monis, JA; Palma, B; Villarin, V; Lim, A Open access courtesy of:
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DOI https://doi.org/10.36487/ACG_repo/2645_04
Cite As:
Monis, JA, Palma, B, Villarin, V & Lim, A 2026, 'Challenges encountered in high-lift block cave extensions and the lessons learned: experience from the Padcal Mine, Philippines', in A van As, D Cumming-Potvin & J Wesseloo (eds), Caving 2026: Proceedings of the Sixth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-16, https://doi.org/10.36487/ACG_repo/2645_04
Abstract:
The Padcal Mine in northern Philippines has operated using block caving since 1963 and continues to extend production into deeper and peripheral ore zones through high-lift block cave development. Since 2021, recurring rockburst events have been recorded during the development and early commissioning of the 798 mining level blocks, particularly within high-lift extensions located at the margins of the active cave footprint. These areas are characterised by abutment stress concentrations and complex stress redistribution associated with staged cave expansion. This paper documents the challenges encountered during the development and commissioning of high-lift block cave extensions, with emphasis on seismic response, ground support performance, dilution control, and block development layout and sequencing. Lessons learned from Padcal highlight the critical role of abutment stress management, the importance of drawpoints connectivity, the limitations of conventional support systems under dynamic loading, and the need for adaptive draw control, undercutting, and development strategies. Mitigation measures implemented include enhanced active support reinforcement, blasting deferment protocols, draw control strategies, and the use of isolation crosscuts to manage cave expansion risks and to achieve successful block commissioning. The outcomes offer practical, experience-based guidance for planning, commissioning, and operating highlift block cave extensions in similarly stressed and seismically active environments.
Keywords: block caving, high-lift cave extension, rockburst, seismic response, ground support, abutment stress, dilution control
References:
Andrieux, P & Hadjigeorgiou, J 2008, ‘The destressability methodology for the assessment of the likelihood of success of a large-scale confined destress blast in an underground mine pillar’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 108, no. 5, pp. 267–274.
Beck, DA & Brady, BHG 2002, ‘Evaluation and application of controlling parameters for seismic events in hard-rock mines’, International Journal of Rock Mechanics and Mining Sciences, vol. 39, no. 5, pp. 633–642.
Brown, ET 2003, Block Caving Geomechanics, Julius Kruttschnitt Mineral Research Centre, Indooroopilly.
Butcher, W, Stacey, TR & Joughin, TR 2005, ‘Mud rushes and methods of combating them’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 105, no. 11, pp. 817–824.
Esterhuizen, HCJ 2018, ‘Controlling the effects of stress and seismicity in a sublevel caving operation’, in Y Potvin & J Jakubec (eds), Caving 2018: Proceedings of the Fourth International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 607–622,
Flores, G & Karzulovic, A 2002, Geotechnical Guidelines for a Transition from Open Pit to Underground Mining, report of the International Caving Study, Julius Kruttschnitt Mineral Research Centre, Brisbane.
Heslop, TG 2000, ‘Block caving – controllable risks and fatal flaws, in G Chitombo (ed.), MassMin 2000: Proceedings of the Second International Conference on Mass Mining, Australasian Institute of Mining and Metallurgy, Melbourne, pp. 583–588.
Kaiser, PK, McCreath, DR & Tannant, DD 1996, Canadian Rockburst Support Handbook, Geomechanics Research Centre, Laurentian University, Sudbury.
Laubscher, DH 2000, A Practical Manual on Block Caving, International Caving Study, Julius Kruttschnitt Mineral Research Centre, Brisbane.
Lunder, PJ & Pakalnis, R 1997, ‘Determination of the strength of hard-rock mine pillars’, CIM Bulletin, vol. 90, no. 1013, pp. 51–55.
Potvin, Y, Wesseloo, J & Heal, D 2010, ‘An interpretation of ground support capacity submitted to dynamic loading’, Mining Technology, vol. 119, no. 4, pp. 233–245.
Snyman, L & Webster, S 2022, ‘Northparkes E48 block cave: the mining history of a successful block cave’, in Y Potvin (ed.), Caving 2022: Proceedings of the Fifth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 95–108,
Talu, S, van As, A, Seloka, W & Henry, R 2010, ‘Lift 2 North extension cave performance’, in Y Potvin (ed.), Caving 2010: Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 407–421,
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