Drover, C, Basson, FRP, Lin, J, Levkovitch, V & Kintzel, R 2022, 'Mechanical-flow coupled simulation of a proposed mult panel sublevel shrinkage', in Y Potvin (ed.), Caving 2022: Proceedings of the Fifth International  Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 767-780, https://doi.org/10.36487/ACG_repo/2205_52
(https://papers.acg.uwa.edu.au/p/2205_52_Drover/)
Abstract: Sublevel shrinkage mining can be applied as a derivative of the sublevel caving (SLC) mining method. In this context, an otherwise conventional SLC approach utilises the continuous introduction of tipped rock backfill into the blasted void to assist in stabilising the hanging wall, footwall and sidewalls of the orebody while the mineralised zone is extracted. The shrinkage methodology is primarily suited for thick, steeply dipping deposits in strong rock with low caveability. Shrinkage projects have several advantages over conventional caving, such as reduced development waste haulage costs and lower surface environmental footprint. However, the shrinkage methodology also carries risks. One major risk factor is the potential for increased dilution due to the dynamic nature of ore and backfill mixing within the cave zone. Dilution might have a very significant impact on the project economics, although it cannot be quantified empirically due to the unique geometry, rock mass characteristics and mine design of each orebody. In this case study, Beck Engineering and Newmont Corporation have collaborated to investigate the feasibility of a sublevel shrinkage caving method using numerical techniques. This particular mining methodology and mine geometry is a unique case study for mechanical-flow coupled modelling. The main objectives of the simulation were to forecast hanging wall damage, rock mass stability at the critical excavations as well as ore recovery. The simulation required an innovative and unique implementation of the LR4-FS4 mechanical-flow coupled simulation framework to realistically simulate the complex physics involved. This paper discusses the complexities of the mine design, the novel simulation approach that was applied for the project, and a selection of the model results focusing on critical infrastructure stability and ore recovery.

Keywords: sublevel shrinkage, flow simulation, coupled modelling, backfill, simulation aided engineering