How to see the forest through the faults: lessons learned from 15 years of fault model updates

Authors: Don, J; Penhall, S; Kinakin, D; Nauman, R Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2535_27

Cite As:
Don, J, Penhall, S, Kinakin, D & Nauman, R 2025, 'How to see the forest through the faults: lessons learned from 15 years of fault model updates', in JJ Potter & J Wesseloo (eds), SSIM 2025: Fourth International Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2535_27



Abstract:
Faults are a critical control in the stability of the pit walls of the Gibraltar Mine. Over the years, geological and geotechnical fault models have been developed for each open pit on an as-needed basis for the design of open pit slope walls, pushbacks or in response to slope instabilities. As the mine life progresses, the smaller open pits at Gibraltar Mine are planned to merge into one large-scale ‘super pit’. Three-dimensional pit-scale fault models at Gibraltar Mine have progressed in a similar fashion, initially developed and updated for each open pit, but have evolved to represent a site-wide structural geologic model. This paper presents a brief summary of the recommended industry best practice for fault model management, and BGC Engineering and Gibraltar Mine’s practice of updating and maintaining the fault model of the Gibraltar Mine. The paper summarises data sources, management and software used in modelling faults, challenges with combining four pit-scale fault models into a single, site-wide model, as well as documentation. A summary of the lessons learned from 15 years of fault model updates is presented, including dealing with disparate datasets, fault confidence, challenges with naming conventions, ownership and establishing a robust verification system.

Keywords: fault, fault model, open pit, geological model, geotechnical model, structural geology, case study, core logging, bench mapping, televiewer data, photogrammetry, specific energy, confidence

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