de Vries, R, Hassell, R & Player, J 2015, 'Geotechnical design considerations for Dugald River — from slot to sequence', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 167-184, https://doi.org/10.36487/ACG_rep/1511_07_de_Vries (https://papers.acg.uwa.edu.au/p/1511_07_de_Vries/) Abstract: Concerns regarding the uncertainty of stope dilution at the MMG Limited’s Dugald River underground mine led to a trial stoping program to acquire full-scale comprehensive geotechnical information and to test the validity of the geotechnical and mining parameters. A total of 19 stopes were mined by sublevel open stoping with cemented rockfill (CRF). Specific studies were completed on the rock mass response to mining, rock stress and property measurements, stope blast vibration monitoring, production drilling deviation, CRF optimisation, relogging of diamond core for structural and geotechnical information. Based on the trial stoping results, key geotechnical inputs into mine design and scheduling were provided. These included: The considerable volume of data and the practical experience gained during the trial mining greatly increased the geotechnical knowledge of the rock mass and its response to mining. This allowed for a wide range of geotechnical design considerations to be applied to the project feasibility study at a higher confidence level.