Figure 4
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Slope failures are an inevitable and often an economically attractive aspect of pit slope design in the mining industry. Industry design standards typically accept up to 30% of benches in surface mines to collapse, provided that they are managed so that no personnel are at risk. Too many failures impact on productivity, and larger scale failures ar...
Context in source publication
Citations
... Due to the complex ground conditions and tropical setting, several instabilities and geotechnical challenges have occurred and were retrospectively reviewed for incorporation into future designs (Bar et al. 2022a, Bar et a. 2022b, Cobián et al. 2022). ...
... Ground failure risks at Pueblo Viejo gold mine are managed using a series of controls including geotechnical design, 24x7 monitoring and response, mine dewatering and slope depressurization, design execution and safe operating practices (Bar et al. 2022a). ...
... The response aspect of this control measure at Pueblo Viejo is divided into two concurrently utilized components (Bar et al. 2022a): ...
Technological improvements including the routine use of aerial photogrammetry, semi-automatic rock mass characterization, three-dimensional slope stability modelling and ground-based radar monitoring (i.e. mapping, modelling and monitoring) can now be applied rapidly to develop a continuously improving digital twin in parallel to an excavation sequence. This is critical for reconciling the effectiveness of geotechnical models for predicting future slope stability (or instability). This paper presents semi-brittle and brittle slope failure case studies from Pueblo Viejo gold mine which were managed using a digital twin approach and multiple layers of monitoring. Monitoring systems used to manage safety risks were developed in response to uncertainties in ground characterization and limitations in slope stability analysis and design, particularly prior to excavation. The near real-time comparison of the three-dimensional model with observed slope conditions allowed critical structures to be added to the geotechnical model as mining progressed.
... Both failures occurred on the eastern walls of Moore (Hazard 180) and Monte Negro (Hazard 220) pits in similar engineering geological conditions. Safety risks associated with these and other pit slope failures at the Pueblo Viejo mine were effectively managed using monitoring instrumentation and a comprehensive operational risk management response process (Bar et al. 2022;Bautista et al. 2023). ...
The Pueblo Viejo gold mine in the Dominican Republic has undergone extensive geotechnical assessments since its construction in 2008, employing various methods to ensure slope stability. Despite these efforts, the absence of 3D numerical assessments to evaluate the life-of-mine plan raised concerns about the reliability of existing slope designs. This paper addresses this gap by presenting a detailed account of back-analyses conducted on two significant slope failures using 3D finite difference method (FDM) simulations. Back-analysis (also called calibration) is the process of bringing the model into agreement with observed and/or measured slope performance. Where available, back-analysis is often the most difficult and time-consuming part of the slope design process. However, calibration is also the most valuable because it adds confidence to design predictions and therefore makes the mine plans more reliable. The study outlines the inputs, numerical methodology, and key assumptions employed in the back-analysis process, emphasizing the calibration of rock mass strength parameters through empirical relations and actual site experience. The findings demonstrate reasonable agreements between the numerical simulations and observed failures, underscoring the importance of incorporating alterations in the definition of geotechnical units, particularly within the Upper Carbonaceous Sediments. Furthermore, the calibration of the numerical model enhances the understanding of rock mass behavior and identifies critical factors influence failure mechanisms. These insights contribute to the refinement of slope design processes, ultimately yielding more reliable designs for future mining operations at Pueblo Viejo.
... • Targeted monitoring using ground-based radar systems. Two overlapping IDS ArcSAR systems were deployed, in conjunction with a 24/7 monitoring and response protocol to facilitate the evacuation of personnel and equipment prior to any collapse (Bar et al. 2022c). Actual Failure: Volume = 10,000 m 3 (refer to Figure 4) ...
Technological improvements in geotechnical mapping, modelling and monitoring now allow a digital twin to be developed and maintained in parallel with mining operations. That is, the routine use of aerial photogrammetry, semi-automatic rock mass characterization, three-dimensional slope stability modelling and ground-based interferometric synthetic aperture radar monitoring allow near real-time comparison of modelled and realized ground conditions. This is critical for reconciling the effectiveness of geotechnical models for predicting future slope stability (or instability). This paper presents a semi-brittle slope failure case study from Pueblo Viejo gold mine which was managed using a digital twin approach. The near real-time comparison of the three-dimensional model with observed slope conditions allowed critical structures to be added to the geotechnical model as mining progressed. This led to the identification of a high risk area that would not have been identified if the digital twin was not implemented & maintained during mining.
