A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Approaches for Estimating Slope Breakback and Stability Longevity for Closure of Large Open Pits
Currently, few guidelines exist for how a practitioner should tackle the quantitative assessment of long-term slope performance for open pit mine closure design. Material degradation, resulting from cumulative incremental time-dependent deterioration and propagation of episodic damaging events (e.g., precipitation and seismicity) is of paramount importance in the closure context, as rockmass competence degradation largely controls long-term slope performance. Deterioration rates are governed not just by intrinsic (material specific) and extrinsic (environmental) factors, but also can be significantly affected by previous mining influences (principally blast damage, slope oversteepening, stress relief, etc.). Suggestions for various empirical, analytical and numerical modelling approaches for assessing impact of degradation on closure design risk are outlined and three key geotechnical closure design challenges for supporting design recommendations commensurate with planned post mining land use (PMLU) risk are discussed. These include:i) defining appropriate safe pit crest standoff distances, ii) assessing likely extent of long-term pit crest creep-strain tolerance zones, and iii) quantifying long-term overall slope stability. A risk-based approach is proposed, comprising initial susceptibility screening for time-dependent degradation, followed by increasing analysis rigour (commensurate with risk), starting with empirical assessments, moving then to first principle deterministic limit equilibrium calculations and finally escalating to numerical assessments involving sequentially calibrated time-stepped degradation models.
Approaches for Estimating Slope Breakback and Stability Longevity for Closure of Large Open Pits
Currently, few guidelines exist for how a practitioner should tackle the quantitative assessment of long-term slope performance for open pit mine closure design. Material degradation, resulting from cumulative incremental time-dependent deterioration and propagation of episodic damaging events (e.g., precipitation and seismicity) is of paramount importance in the closure context, as rockmass competence degradation largely controls long-term slope performance. Deterioration rates are governed not just by intrinsic (material specific) and extrinsic (environmental) factors, but also can be significantly affected by previous mining influences (principally blast damage, slope oversteepening, stress relief, etc.). Suggestions for various empirical, analytical and numerical modelling approaches for assessing impact of degradation on closure design risk are outlined and three key geotechnical closure design challenges for supporting design recommendations commensurate with planned post mining land use (PMLU) risk are discussed. These include:i) defining appropriate safe pit crest standoff distances, ii) assessing likely extent of long-term pit crest creep-strain tolerance zones, and iii) quantifying long-term overall slope stability. A risk-based approach is proposed, comprising initial susceptibility screening for time-dependent degradation, followed by increasing analysis rigour (commensurate with risk), starting with empirical assessments, moving then to first principle deterministic limit equilibrium calculations and finally escalating to numerical assessments involving sequentially calibrated time-stepped degradation models.
Approaches for Estimating Slope Breakback and Stability Longevity for Closure of Large Open Pits
Atlantis Highlights in Engineering
Hammah, Reginald E. (editor) / Javankhoshdel, Sina (editor) / Yacoub, Thamer (editor) / Azami, Alireza (editor) / McQuillan, Alison (editor) / Carter, Trevor G. (author) / Lorig, Loren J. (author) / Eberhardt, Erik (author) / de Graaf, Phil J. H. (author)
Rocscience International Conference ; 2023 ; Toronto, ON, Canada
Proceedings of the Rocscience International Conference 2023 (RIC2023) ; Chapter: 49 ; 505-521
2023-11-07
17 pages
Article/Chapter (Book)
Electronic Resource
English
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