Dunn, MJ 2015, 'How reliable are your design inputs?', in Y Potvin (ed.), Proceedings of the International Seminar on Design Methods in Underground Mining
, Australian Centre for Geomechanics, Perth, pp. 367-381.
A variety of methods are used in underground design, including empirical, observational, analytical and numerical modelling. All design methods require inputs, and these are based on data obtained from core logging, mapping, laboratory testing, field observations and monitoring. This data then has to be compiled and interpreted so that meaningful and reliable design inputs can be derived.
Design inputs are required to a have reliability and confidence level that is commensurate with the level of design (scoping through to operational) and that will ultimately satisfy the design reliability and acceptable risk profile for the design. To obtain reliable design inputs, data of sufficient quantity and quality has to be collected and analysed. The variability of this data has to be understood so that reliable inputs can be derived.
Currently, very little quantitative guidance exists in the literature on assessing the reliability and confidence of geotechnical studies and design, although there have been attempts by various authors (Haile 2004; Haines et al. 2006; Read & Stacey 2009; Dunn et al. 2011) to qualitatively describe what level of geotechnical data is required. Recently, a number of authors have outlined methods that could be applied to assess the reliability of geotechnical data.
These methods have been discussed, and the application of some methods has been demonstrated on data from underground feasibility studies to assess the reliability of design inputs. A preliminary rating scheme to assess the reliability of geotechnical models and design inputs has been proposed.
Baecher, GB & Christian, JT 2003, Reliability and statistics in geotechnical engineering, Wiley, London.
Barton, N, Lien, R & Lunde, J 1974, ‘Engineering classification of rock masses for the design of rock support’, Rock Mechanics, vol. 6, pp. 189-236.
Beer, G & Meek, JJ 1982, ‘Design curves for roofs and hangingwalls in bedded rocks based on ‘voussior’ beam and plate solutions’, Transactions of the Institute of Mining and Metallurgy,vol. 91, pp. A18-A22.
Bieniawski, ZT 1976, ‘Rock mass classification in rock engineering’, in ZT Bieniawski (ed.), Exploration for rock engineering: Proceedings of the Symposium on Exploration for Rock Engineering, A.A. Balkema, Lisse, pp. 97-106.
Bieniawski, ZT 1989, Engineering Rock Mass Classifications, John Wiley & Sons, New York.
Carter, TG 2000, ‘An update on the scaled span concept for dimensioning surface crown pillars for new or abandoned mine workings, Proceedings of the 4th North American Rock Mechanics Conference, American Rock Mechanics Association, Minneapolis, MN, pp. 465-472.
Cepuritis, P & Villaescusa, E 2012, ‘A reliability-based approach to open stope span design in underground mining’, Proceedings of the 6th International Conference and Exhibition on Mass Mining (MassMin 2012), Canadian Institute of Mining, Metallurgy and Petroleum, Westmount, QC, CD-Rom only.
Department of Industry and Resources1997, Geotechnical considerations in underground mines – guideline, viewed 11 May 2015,
Dunn, MJ 2014, ‘Geotechnical models and data confidence in mining geotechnical design’, Proceedings of the Third Australasian Ground Control in Mining Conference (AusRock 2014), The Australasian Institute of Mining and Metallurgy, Melbourne
Dunn, MJ & Laas, JJ 1999, ‘The panel rating system – a risk management tool’, in TO Hagan (ed.), Proceedings of the Second Southern African Rock Engineering Symposium, South African National Institute of Rock Engineering (SANIRE), Johannesburg, pp. 28-32.
Dunn, MJ, Basson, FR & Parrott, TT 2011, ‘Geotechnical data – a strategic or tactical issue?’, in Y Potvin (ed.), Proceedings of the Fourth International Seminar on Strategic versus Tactical Approaches in Mining, Australian Centre for Geomechanics, Perth, pp. 21-30.
Gill, DE, Corthésy, R & Leite, MH 2005, ‘Determining the minimal number of specimens for laboratory testing of rock properties’, Engineering Geology, vol. 78, pp. 29-51.
Goodman, RE & Shi, G 1985, Block theory and its application in rock engineering, Prentice Hall, Upper Saddle River, NJ.
Hadjigeorgiou, J & Harrison, JP 2011, ‘Uncertainty and sources of error in rock engineering’, in Q Qian & X Zhou (eds), Proceedings of the 12th ISRM International Congress on Rock Mechanics, Harmonising Rock Engineering and the Environment, CRC Press, Leiden, pp. 2063-2067.
Haile, A 2004, ‘A reporting framework for geotechnical classification of mining projects’, Bulletin of the Australasian Institute of Mining and Metallurgy, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 30-37.
Haines, A, Swart, A & Kruger, A 2006, ‘Proactively mitigating geotechnical risks in open pit and underground mining’, Proceedings of the Second International Seminar on Strategic versus Tactical Approaches in Mining, Australian Centre for Geomechanics, Perth.
Harr, ME 1996, Reliability-based design in civil engineering, McGraw-Hill, Dover, NY.
Hedley, DGF & Grant, F 1972, ‘Stope-and-pillar design for the Elliot Lake Uranium Mines’, Bulletin of the Canadian Institute of Mining and Metallurgy, vol. 65, no. 273, pp. 37-44.
Hoek, E & Brown, ET 1988, ‘The Hoek–Brown failure criterion — a 1988 update’, in JC Curran (ed.), Proceedings of the 15th Canadian Rock Mechanics Symposium, Canadian Rock Mechanics Association, pp. 31-38.
Hoek, E & Marinos, P 2000, ‘GSI: a geologically friendly tool for rock mass strength estimation’, Proceedings of the GeoEng 2000 Conference, pp. 1422-1442.
Hutchinson, DJ & Falmagne, V 2000, ‘Observational design of underground cablebolt support systems utilizing instrumentation’, Bulletin of Engineering Geology and the Environment, vol. 58, no. 3, pp. 227-241.
Joint Ore Reserves Committee 2004, JORC Code: Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, Joint Ore Reserves Committee, South Carlton.
Joint Ore Reserves Committee 2012, JORC Code: Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, Joint Ore Reserves Committee, South Carlton.
Lunder, P & Pakalnis, RC 1997, ‘Determination of the strength of hard rock pillars’, Bulletin of the Canadian Institute of Mining, Metallurgy and Petroleum, vol. 90, no. 1013, pp. 51-55.
Mathews, KE, Hoek, E, Wyllie, DC & Stewart, S 1981, Prediction of stable excavation spans for mining at depths below 1,000 metres in hard rock / Golder Associates, CANMET Library & Documentation Services Division, Vancouver.
McCarthy, PL 1993, Objectives of feasibility studies, AMC Library.
McMahon, BK 1985, Geotechnical design in the face of uncertainty: EH Davis memorial lecture, Australian Geomechanics Society, Barton.
Peck, RB 1969, ‘Advantages and limitations of the observational method in applied soil mechanics’, Geotechnique, vol. 19, no. 2,
Potvin, Y 1988, ‘Empirical open stope design in Canada’ PhD thesis, University of British Columbia.
Read, J & Stacey, P 2009, Guidelines for open pit slope design, CSIRO Publishing, Collingwood.
Steffen, OKH 1997, ‘Planning of open pit mines on risk basis’, Journal of The Southern African Institute of Mining and Metallurgy, vol. 2, pp. 47-56.
Wiles, TD 2006, ‘Reliability of numerical modelling predictions’, International Journal of Rock Mechanics and Mining Sciences,
vol. 43, pp. 454-472.
Wiles, TD 2015, Map3D User’s Manual, Map3D International Ltd, viewed 11 May 2015,