Malek, F, Maloney, S, Hossack, A & Nickson, S 2024, 'Trialling the application of hydraulic preconditioning at Creighton Deep', in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 1265-1276, https://doi.org/10.36487/ACG_repo/2465_83
(https://papers.acg.uwa.edu.au/p/2465_83_Malek/)
Abstract: Vale has completed several phases of work to explore the use of hydraulic preconditioning as a mechanism for the reduction of the maximum magnitude of mining-induced seismic events in highly stressed ground. Hydraulic preconditioning involves the isolation and pressurisation of diamond drillhole intervals to create additional fracture systems to reduce the seismic response by lowering the rock mass quality. The ultimate goal is to enable rotation of the major principal stress around future mining areas to reduce stress related interaction between adjacent orebodies.
The phased work plan was executed at Vale’s Ontario Operations mines between 2017 and 2024. Phase 1 was designed around determining if fracture initiation could be executed under high-stress conditions in strong rock using a high-pressure, low flow rate pumping system at Copper Cliff Mine. Phase 2a involved the underground deployment of a prototype high-pressure, high flow rate pumping system at Creighton Mine to evaluate the ability to initiate and propagate fractures in rock mass at greater depth. Phase 2b involved a full-scale preconditioning curtain application, which was completed in early 2024, to trial stress shadowing between two different orebodies at Creighton Mine.
This paper will briefly review each of the phased work plans and results, with particular comment on the preparation logistics that evolved as the project advanced. Emphasis will be placed on the full-scale preconditioning curtain application (Phase 2b) and the associated results obtained so far. A review of the challenges and benefits of utilising a hydraulic preconditioning approach in deep mining applications will be presented.

Keywords: hydraulic preconditioning, treatment, seismic, fracture, initiation, propagation