McKenzie, CK 2016, 'Blasting near open pit walls', in PM Dight (ed.), APSSIM 2016: Proceedings of the First Asia Pacific Slope Stability in Mining Conference
, Australian Centre for Geomechanics, Perth, pp. 83-94, https://doi.org/10.36487/ACG_rep/1604_0.5_McKenzie
The topic of blasting near pit walls is one that invokes mixed reactions from different mining departments. For many mine operations and mine scheduling departments, it often represents a significant disruption to efficient work flow, while to geotechnical departments it represents a critical component in the task of delivering safe and competent pit walls and compliance with pit slope design.
Many different approaches exist to help achieve the desired end result of safe pit walls and compliance with pit slope design, suggesting that there is no single best-solution. This paper explores some of the contemporary paradigms which strive to achieve the desired end result, with a particular focus on presenting a thought process aimed at trying to avoid unnecessary and ineffective restrictions on mining practices and wall control blasting. Practices such as reduced blasthole diameter, pre-splitting, trim blasting, initiation sequences and systems and reduced blast size will be explored using modelling based upon field measurements. How well do we understand the impacts of blasting on pit wall integrity and pit slope stability?
While there is no single design that suits all mining applications, there is a single thought process that should lead each mine to quite quickly decide on the most appropriate solutions for areas of different sensitivity regarding slope stability.
Bauer, A 1982, ‘Wall Control Blasting in Open Pits’, in Proceedings of the 14th Canadian Rock Mechanics Symposium, pp. 3–10.
Blair, DP & Armstrong, LW 2001, ‘The influence of burden on blast vibration’, Fragblast – International Journal for Blasting and Fragmentation, Balkema, Rotterdam.
Brent, GF, Smith, GE & Lye, GN 2001, ‘Studies on the Effect of Burden on Blast Damage and the Implementation of New Blasting Practices to Improve Productivity at KCGM’s Fimiston Mine’, in Explo 2001 Proceedings, AusIMM.
Calder, P 1977, ‘Pit Slope Manual, Chapter 7 - Perimeter Blasting’, CANMET Report 77-14, Canadian Center for Mineral and Energy Technology.
Chiappetta, F 1990, ‘Pre-splitting and controlled blasting techniques’, in Proceedings of the 2nd High Tech Seminar, ISEE, Cleveland.
Green, B 2015, ‘Megablasts – Enabling technologies in BHP Billiton Iron Ore’, in Proceedings of the International Symposium on Rock Fragmentation by Blasting, pp. 599–606.
Hoek, E 2012, ‘Blast Damage Factor, D’, Technical note for Rocscience, 2 February 2012.
Hoek, E, Carranza-Torres, CT & Corkum, B 2002, ‘Hoek-Brown failure criterion-2002 edition’, in Proceedings of the Fifth North American Rock Mechanics Symposium, Toronto, vol. 1, pp. 267–273.
Holmberg, R & Persson, P-A 1979, ‘Design of tunnel perimeter blasthole patterns to prevent rock damage’, Tunnelling '79: Proceedings of the Second International Symposium, IMM, London, pp. 280–283.
LeJuge, GE, Jubber, L, Sandy, DA & McKenzie, CK 1994, ‘Blast Damage Mechanisms In Open Cut Mining’, Open Pit Blasting Workshop 94, AusIMM.
McKenzie, CK 2012, ‘Limits Blast Design: Controlling Vibration, Gas Pressure & Fragmentation’, in Singh & Sinha (eds), Proceedings of the 10th International Symposium on Rock Fragmentation by Blasting, New Delhi.
McKenzie, CK & Holley, K 2004, ‘A study of damage profiles behind blasts’, in Proceedings of the 30th Annual Conference on Explosives and Blasting Techniques, International Society of Explosives Engineers, vol. 2.
McKenzie, CK, Scherpenisse, CR, Arriagada, J & Jones, J 1995, ‘Application of computer assisted modelling to final wall blast design’, in Explo ‘95 Proceedings, AusIMM , pp. 285–292.
Moreno, E, Sanhueza, JC & Vanbrabant, F 2008, ‘Balance fragmentación-daño en zona primaria en Mina Los Pelambres, ASIEX’, VI Jornadas de Tronadura, Pucón, Chile. [in Spanish]
Ouchterlony, F 1993, ‘Blast damage predictions from vibration measurements at the SKB underground laboratories at Äspö in Sweden’, in Proceedings of the 19th Annual Conference on Explosives and Blasting Techniques, International Society of Explosives Engineers, vol. 2.
Ouchterlony, F 1997, ‘Prediction of crack lengths in rock after cautious blasting with zero inter-hole delay’, International Journal for Blasting and Fragmentation, vol. 1, pp. 417–444.
Ouchterlony, F, Nie, S, Nyberg, U & Deng, J 1996, ‘Monitoring of large open cut rounds by VOD, PPV and gas pressure measurements’, in B Mohanty (ed.), Proceedings of the 5th International Symposium on Rock Fragmentation by Blasting, Balkema, Rotterdam, pp. 167–176.
Spathis, AT, Smith, GE, Yacob, I & Labriola, A 2001, ‘Wall Control at the Freeport Grasberg Opencut Mine: Vibration and Gas Penetration Measurements as a Precursor to Improvements’, in Proceedings of the 27th Annual Conference on Explosives and Blasting Techniques, International Society of Explosives Engineers, vol. 2.
Workman, JL & Calder, PN 1991, ‘A method for calculating the weight of charge to use in large hole pre-splitting for cast blasting operations’, in Proceedings of the 17th Annual Conference on Explosives and Blasting Techniques, International Society of Explosives Engineers, vol. 2.