Joughin, WC 2008, 'A Preliminary Model for Quantifying the Risk of Rockfalls and Evaluating the Benefits of Safety Spending', in Y Potvin, J Carter, A Dyskin & R Jeffrey (eds), Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium
, Australian Centre for Geomechanics, Perth, pp. 589-604, https://doi.org/10.36487/ACG_repo/808_81
Safety spending in the mining industry is often viewed as a necessary but expensive overhead cost. This mindset places safety and productivity in direct opposition to each other, while improved safety practices could actually lead to better productivity. Alternatively, from a pure safety perspective, the perception also exists that more is better in terms of safety spending, while the additional spending may not necessarily lead to a significant reduction in risk. In order to evaluate the real benefits of safety spending in mitigating rockfalls and their consequences a risk model is being developed as part of an ongoing SIMRAC research programme. A preliminary model has been developed and is presented in this paper. The model will enable the quantification of the likelihood of occurrence rockfalls under various conditions with different support systems. It will also allow the likelihood of occurrence of the various direct and indirect consequences of rockfalls to be determined. The effect of various monitoring and mitigating strategies can also be evaluated through the model. If the costs associated with these consequences are known, then the model can be used to determine the expected cost of rockfalls. The overall cost of a safety strategy can then be determined as the sum of the cost of implementing and maintaining the strategy and the expected cost of rockfalls with the strategy implemented. It will provide a method for designing according to tolerable levels of safety risk.
Barton, N., Lien, R. and Lunde, J. (1974) Engineering classifications of rock masses for the design of tunnel support. Rock Mechanics. 6 (4), pp. 189–236.
Brady, B.H.G. and Brown, E.T. (2006) Rock Mechanics for Underground Mining, third edition. London, Chapman and Hall, pp. 230–235.
Brink, A.v.Z and Roberts, M.K.C. (2007) Early Warning and/or Continuous Risk Assessment of Rockfalls in Deep South African Mines. Fourth International Seminar on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, Australia, November 2007, pp. 437–450.
Contreras, L.F., LeSeur, R. and Maran, J. (2006) A case study of risk evaluation at Cerrejon mine. Proceedings International Symposium on Stability of Rock Slopes in Open Pit and Civil Engineering, Cape Town, p. 202.
Diederichs, M.S. and Kaiser, P.K. (1999) Stability of large excavations in laminated hard rock masses: the voussoir analogue revisited. Int. J. of Rock Mech. and Mining Sciences. Vol. 36, pp. 97–117.
Dunn, M., Earl, P.J. and Watson, J. (2008) Support design using probabilistic keyblock methods. 6th International Symposium on Ground Support in Mining and Civil Engineering Construction, Cape Town, South Africa.
Esterhuizen, G.S. (2003) JBlock User’s Manual.
Esterhuizen, G.S. and Streuders, S.B. (1998) Rockfall hazard evaluation using probabilistic keyblock analysis. Jour. S. Afr. Inst. Min. Metall., Vol. 98, No. 2, pp. 59–63.
Goodman, R.E. and Shi, G. (1985) Block theory and its application in rock engineering. Prentice Hall, 338 p.
Grenon, M. and Hadjigeorgiou, J. (2003) Open stope stability using 3D joint networks. Rock Mech. Rock Engng. 36 (3), pp. 183–208.
Harr, M.E. (1987) Reliability based design in civil engineering. Mc Graw-Hill, New York, pp. 205–220.
Hutchinson, D.J. and Diederichs, M.S. (1998) Cable bolting in underground mines. BitTech Publishers Ltd. Richmond, British Columbia. ISBN 0-921095-37-6, pp. 221–240.
Joughin, W.C., Armstrong, R. and Pethö, S.Z. (2006) Assessment of the stability of longhole stope backs at South Deep. Proceedings of SANIRE 2006 – Facing the challenges, Rustenberg.
Laubscher, D.H. (1990) A Geomechanics classification system for the rating of rock mass in mine design. J.S. Afr. Inst. Min. Metall. Vol. 90, No. 10, pp. 257–273.
Piper, P.S. and Malan, D.F. (2008) The in-situ performance of elongate support – myths and realities. 6th International Symposium on Ground Support in Mining and Civil Engineering Construction, Cape Town 2008, pp. 299–316.
Potvin, Y. (1998) Empirical stope design in Canada. PhD Thesis, University of British Columbia.
Potvin, Y. and Hadjigeorgiou, J. (2001) The stability graph method for open stope design. In W.A. Hustrulid and R.L. Bullock (editors), Underground mining methods: engineering fundamentals and international case studies. Society for Mining Metallurgy and Exploration, Inc SME, pp. 513–520.
Rosenblueth, E. (1975) Point estimates for probability moments. Proceedings of the National Academy of Sciences of the United States of America Vol. 72 No. 10, pp. 3812–3814.
Stacey, T.R. (2007) Is Rock Engineering addressing risk appropriately? SANIRE Free State Symposium – Re-defining the boundaries Part II, Vereeniging, South Africa, pp. 73–83.
Stacey, T.R., Terbrugge, P.J. and Wesseloo, J. (2007) Risk as a Rock Engineering design criterion. In Challenges in Deep level mining. Y. Potvin, J. Hadjigeorgiou, T.R. Stacey (editors), Australian Centre for Geomechanics, Perth, Australia, pp. 17–23.
Swart, A.H., Stacey, T.R., Wesseloo, J., Joughin, W.C., Le Roux, K., Walker, D. and Butcher, R. (2000) Investigation of factors governing the stability/instability of stope panels in order to define a suitable design methodology for near surface and shallow mining operations. Safety in Mines Research Advisory Committee (SIMRAC) final project report OTH501.
Terbrugge, P.J., Wesseloo, J., Venter, J. and Steffen, O.K.H. (2006) A risk consequence approach to open pit slope design. Jnl. S.Afr. Inst. Min. Metall., Vol. 106, pp. 503–511.