Brown, K, Webster, S, Bruning, T, Garcia, O & Campbell, AD 2022, 'An iterative design and schedule approach to the E22 block cave project and production planning at CMOC Northparkes Mines: a case study', in Y Potvin (ed.), Caving 2022: Fifth International Conference on Block and Sublevel Caving
, Australian Centre for Geomechanics, Perth, pp. 303-314, https://doi.org/10.36487/ACG_repo/2205_20
The scheduling of a block cave mine is an iterative process, ranging from early exploration, sampling and metallurgical test work to conceptual designs encompassing footprint RL, drawpoint layout, development requirements, and production modelling. This paper discusses the iterative approach used by CMOC Northparkes for the mine design and production scheduling of the E22 block cave pre-feasibility study. During pre-feasibility, Northparkes uses the Geovia® Gems Dassault Personal Computer Block Cave (PCBC) software package for production scheduling and Deswik® for development scheduling. In this study, the cave development sequence is optimised by pairing the output of each platform, allowing a coupled feedback loop of scheduling decisions. More specifically, the modelling process at Northparkes consists of several stages, beginning with the initial design, which uses a resource block model and the Gems PCBC software package to determine an appropriate footprint RL alongside an approximate production profile. Once a suitable footprint and drawpoint layout is selected, the Deswik software package is used to create a mine design and development schedule, which are used to identify milestones for future production scenarios and ore flow simulations. It is found that the predominant impact of the development schedule on the production profile is the drawbell opening sequence. There were numerous constraints as to why an assumed opening sequence can/cannot be met. However, by diligently scheduling development, the scope of production scenarios can be limited to achievable plans. As models and simulations are developed throughout pre-feasibility study studies, limitations of production rates, caving sequences and development schedules are identified. These deficiencies are addressed by completing an iterative design and scheduling feedback loop within the production planning environment to produce a realistic mine plan. Northparkes have utilised numerical modelling for verifying production/caving scenarios and to understand the stability of the footprint design. This combined approach identified opportunities and limitations, which have been used to update the subsequent design and schedule iterations, leading to an optimised mine that is supported by realistic assumptions. This approach has allowed Northparkes Mines to progress the E22 block cave from the prefeasibility study into the feasibility stage with confidence in a robust production and development schedule.
Keywords: block caving, PCBC, footprint design, scheduling, undercut
Beck Engineering 2021, E22 Subsidence and Caving Options Assessment, Beck Engineering, Chatswood West.
Brown, ET 2003, Block Caving Geomechanics: The International Caving Study I 1997-2000, Julius Kruttschnitt Mineral Researh Centre, The University of Queensland, Indooroopilly, pp. 191–194.
Laubscher, DH 1990, ‘A geomechanics classification system for the rating of rock mass in mine’, Journal of the South African Institute of Mining and Metallurgy, pp. 257–273.
Trueman, R & Mawdesley, C 2003, ‘Predicting cave initiation and propagation’, CIM Bulletin, vol. 96, no. 1071, pp. 54–59.