Authors: Ghadirianniari, S; McDougall, S; Eberhardt, E; Llewelyn, K; Campbell, R; Moss, A

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DOI https://doi.org/10.36487/ACG_repo/2205_41

Cite As:
Ghadirianniari, S, McDougall, S, Eberhardt, E, Llewelyn, K, Campbell, R & Moss, A 2022, 'Impact of draw strategy on wet muck spill hazard severity at the Deep Ore Zone mine', in Y Potvin (ed.), Caving 2022: Fifth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 597-610, https://doi.org/10.36487/ACG_repo/2205_41

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Abstract:
A wet muck spill is a sudden inflow of wet material into an underground mine excavation, typically from an extraction level drawpoint. Wet muck spills pose a major risk to personnel safety, assets (equipment and infrastructure) and production. A key factor that determines the extent and impact of a wet muck spill is its severity, which can be described by its volume, flow velocity and runout distance. Evidence from historical wet muck spill events has shown that the volume and runout distance of a spill can exceed 3,000 m3 and 200 m, respectively. Wet muck spill severity assessments are an essential component of a mine’s risk management plan, serving to guide the delineation of potential wet muck impact zones and the development of effective mitigation strategies. The potential for the occurrence of a severe spill event increases as the amount of fines and water exposed at a drawpoint increase. One strategy to mitigate the risk of a severe spill event is to limit draw at high-risk drawpoints or close them entirely. However, this approach might not be as effective for a mature cave with high quantities of rapidly percolating fine material and stored water, where many drawpoints are likely prone to severe spills. In such conditions, understanding how draw strategy influences spill severity can guide risk-informed draw optimisation, with the goal of minimising severe spill events. A practical approach towards a better understanding of how draw strategy contributes to severe spills must include a systematic review of historical spill data. In this study, statistical methods were used to analyse spill data from the Deep Ore Zone (DOZ) cave mine in Papua, Indonesia, with the aim of identifying trends between the probability of a high-volume spill (defined as spill volume > 500 m3) and draw strategy. Draw strategy was quantified by two draw-related variables: draw rate and differential draw index. Spill probability was calculated based on the frequency of high-volume spill observations at different ranges of these variables. Results from this study showed that high-volume spills were more likely to happen under high draw rates and non-uniform draw conditions. The probability of a high-volume spill was highest when both draw rate and differential draw index were in their upper ranges, and much less when either of these variables were in their lower ranges.

Keywords: wet muck spill severity, risk assessment, spill volume, draw strategy, differential draw index

References:
Armitage, P 1955, ‘Tests for linear trends in proportions and frequencies’, Biometrics, vol 11, pp. 375–386.
Butcher, R, Stacey, TR & Joughin, WC 2005, ‘Mud rushes and methods of combating them’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 105, pp. 817–824.
Call & Nicholas Inc., 1998, IOZ Wetmuck Study, PT Freeport Indonesia, internal report.
Castro, RL, Basaure, K, Palma, S & Vallejos, J 2017, ‘Geotechnical characterization of ore related to mudrushes in block caving mining’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 117, pp. 275–284.
Castro, R, Garcés, D, Brzovic, A & Armijo, F 2018, ‘Quantifying wet muck entry risk for long-term planning in block caving’, Rock Mechanics and Rock Engineering, vol. 51, pp. 2965–2978.
Dorador, L 2016, Experimental Investigation of the Effect of Broken Ore Properties on Secondary Fragmentation During Block Caving, PhD thesis, The University of British Columbia, Vancouver.
Edgar, I, Prasetyo, R & Wilkinson, M 2020, ‘Deep Ore Zone mine wet ore mining empirical learnings, mining process evolution and development pathway’, 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. 385–393,
Ghadirianniari, S, McDougall, S, Eberhardt, E, Varian, J, Llewellyn, K, Campbell, R & Moss, A 2023, ‘Statistical analysis of the impact of ore draw strategies on inrush hazard susceptibility in a panel cave mine’ (unpublished), International Journal of Rock Mechanics and Mining Sciences, Elsevier, Amsterdam.
Hekmat, A, Anani, A, Tapia, F & Navia, I 2018, ‘Mud inflow risk assessment in block caving operation based on AHP comprehensive method’, in E Widzyk-Capehart, A Hekmat & R Singhal (eds), Proceedings of the 18th Symposium on Environmental Issues and Waste Management in Energy and Mineral Production, Springer, Berlin, pp. 51–66.
Holder, A, Rogers, A, Bartlett, P & Keyter, K 2013, ‘Review of mud rush mitigation on Kimberley's old scraper drift block caves’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 113, pp. 529–537.
Hubert, G, Dirdjosuwondo, S, Plaisance, R & Thomas, L 2000, ‘Tele-operation at Freeport to reduce wet muck Hazards’, Proceedings of MassMin 2000, The Australasian Institute of Mining and Metallurgy, Carlton, pp. 173–179.
Jakubec, J, Clayton, R, & Guest, A 2012,’Mudrush risk evaluation’, Proceedings of the Sixth International Conference and Exhibition on Mass Mining, Canadian Institute of Mining, Metallurgy and Petroleum, Vancouver.
Laubscher, D 2000, A practical Manual on Block Caving, Julius Kruttschnitt Mineral Research Centre, Brisbane.
Navia, I, Castro, R & Valencia, M 2014, ‘Statistical analyses of mud entry at Diablo Regimiento sector—El Teniente’s Mine’, Proceedings of the Third International Symposium on Block and Sublevel Caving, University of Chile, Santiago.
Pierce, M 2010, A Model for Gravity Flow of Fragmented Rock in Block Caving Mines, The University of Queensland, St Lucia.
Ramadhan, M, Wicaksono, D, Haflil, D & Antoro, B 2015, ‘New Perspective of wet muck risk map: lesson learned from wet muck spill in coarse fragmentation at Deep Ore Zone (DOZ) block caving mine, Papua, Indonesia’, Proceedings of 24th Indonesian Mining Professionals Annual Meeting, Jakarta, pp. 198–207.
Samosir, E, Basuni, J, Widijanto, E & Syaifullah, T 2008, ‘The management of wet muck at PT Freeport Indonesia’s deep ore zone mine’, Proceedings of the Fifth International Conference and Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 323–332.
Szwedzicki T, Widijanto, E & Sinaga, F 2004, ‘Propagation of a caving zone: a case study from PT Freeport, Indonesia’, in A Karzulovic & MA Alfaro (eds), Proceedings of Massmin 2004, Instituto de Ingenieros de Chile, Santiago.
Widijanto, E, Arsana, N & Srikant, A 2006, ‘Geotechnical challenges in the DOZ block cave mine’, Proceedings of Rock Mechanics in Underground Construction: Proceedings of the 4th Asian Rock Mechanics Symposium, World Scientific, Singapore.
Widijanto, E, Sunyoto, WS, Wilson, A, Yudanto, W & Soebari, L 2012, ‘Lessons learned in wet muck management in Ertsberg East Skarn System of PT Freeport Indonesia’, Proceedings of the Fifth International Conference and Exhibition on Mass Mining, Canadian Institute of Mining, Metallurgy and Petroleum, Vancouver.
Wilson, A, Purba, A, Sjadat, A , Carr, C & Chitombo, G 2016, ‘Progressing cave performance into the later stages of the Deep Ore Zone mine’, Proceedings of the Seventh International Conference and Exhibition on Mass Mining, The Australasian Institute of Mining and Metallurgy, Carlton, pp. 285–292.




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