The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit
Abstract The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability...
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crdegruytopen:10.2478/amsc-2014-0043 2023-05-15T16:13:47+02:00 The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit Cała, Marek Kowalski, Michał Stopkowicz, Agnieszka 2014 http://dx.doi.org/10.2478/amsc-2014-0043 https://www.degruyter.com/view/j/amsc.2014.59.issue-3/amsc-2014-0043/amsc-2014-0043.pdf unknown Walter de Gruyter GmbH Archives of Mining Sciences volume 59, issue 3 ISSN 1689-0469 journal-article 2014 crdegruytopen https://doi.org/10.2478/amsc-2014-0043 2017-08-15T20:49:47Z Abstract The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability problems, it proved necessary to perform a serious stability analyses. The Hyttemalmen open pit was designed with a depth up to 100 m, a bench height of 24 m and a ramp width of 10 m. The rock formation in the iron mining district of Kirkenes is called the Bjornevaten Group. This is the most structurally complicated area connected with tectonic process such as folding, faults and metamorphosis. The Bjornevaten Group is a volcano-sedimentary sequence. Rock slope stability depends on the mechanical properties of the rock, hydro-geological conditions, slope topography, joint set systems and seismic activity. However, rock slope stability is mainly connected with joint sets. Joints, or general discontinuities, are regarded as weak planes within rock which have strength reducing consequences with regard to rock strength. Discontinuities within the rock mass lead to very low tensile strength. Several simulations were performed utilising the RocLab (2007) software to estimate the gneiss cohesion for slopes of different height. The RocLab code is dedicated to estimate rock mass strength using the Hoek-Brown failure criterion. Utilising both the GSI index and the Hoek-Brown strength criterion the equivalent Mohr-Coulomb parameters (cohesion and angle of internal friction) can be calculated. The results of 3D numerical calculations (with FLA3D code) show that it is necessary to redesign the slope-bench system in the Hyttemalmen open pit. Changing slope inclination for lower stages is recommended. The minimum factor of safety should be equal 1.3. At the final planned stage of excavation, the factor of safety drops to 1.06 with failure surface ranging through all of the slopes. In the case of a slope angle 70° for lower stages, FS = 1.26, which is not enough to provide slope stability. Another series of calculations were therefore performed taking water table lowering into consideration, which increases the global safety factor. It was finally evaluated, that for a water table level of 72 m the factor of safety equals 1.3, which is enough to assure global open-pit stability. Article in Journal/Newspaper Finnmark Kirkenes Finnmark Sciendo (de Gruyter - via CrossRef) Norway Hoek ENVELOPE(-65.050,-65.050,-66.000,-66.000) Archives of Mining Sciences 59 3 609 620 |
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Abstract The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability problems, it proved necessary to perform a serious stability analyses. The Hyttemalmen open pit was designed with a depth up to 100 m, a bench height of 24 m and a ramp width of 10 m. The rock formation in the iron mining district of Kirkenes is called the Bjornevaten Group. This is the most structurally complicated area connected with tectonic process such as folding, faults and metamorphosis. The Bjornevaten Group is a volcano-sedimentary sequence. Rock slope stability depends on the mechanical properties of the rock, hydro-geological conditions, slope topography, joint set systems and seismic activity. However, rock slope stability is mainly connected with joint sets. Joints, or general discontinuities, are regarded as weak planes within rock which have strength reducing consequences with regard to rock strength. Discontinuities within the rock mass lead to very low tensile strength. Several simulations were performed utilising the RocLab (2007) software to estimate the gneiss cohesion for slopes of different height. The RocLab code is dedicated to estimate rock mass strength using the Hoek-Brown failure criterion. Utilising both the GSI index and the Hoek-Brown strength criterion the equivalent Mohr-Coulomb parameters (cohesion and angle of internal friction) can be calculated. The results of 3D numerical calculations (with FLA3D code) show that it is necessary to redesign the slope-bench system in the Hyttemalmen open pit. Changing slope inclination for lower stages is recommended. The minimum factor of safety should be equal 1.3. At the final planned stage of excavation, the factor of safety drops to 1.06 with failure surface ranging through all of the slopes. In the case of a slope angle 70° for lower stages, FS = 1.26, which is not enough to provide slope stability. Another series of calculations were therefore performed taking water table lowering into consideration, which increases the global safety factor. It was finally evaluated, that for a water table level of 72 m the factor of safety equals 1.3, which is enough to assure global open-pit stability. |
format |
Article in Journal/Newspaper |
author |
Cała, Marek Kowalski, Michał Stopkowicz, Agnieszka |
spellingShingle |
Cała, Marek Kowalski, Michał Stopkowicz, Agnieszka The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
author_facet |
Cała, Marek Kowalski, Michał Stopkowicz, Agnieszka |
author_sort |
Cała, Marek |
title |
The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
title_short |
The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
title_full |
The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
title_fullStr |
The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
title_full_unstemmed |
The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit |
title_sort |
three-dimensional (3d) numerical stability analysis of hyttemalmen open-pit |
publisher |
Walter de Gruyter GmbH |
publishDate |
2014 |
url |
http://dx.doi.org/10.2478/amsc-2014-0043 https://www.degruyter.com/view/j/amsc.2014.59.issue-3/amsc-2014-0043/amsc-2014-0043.pdf |
long_lat |
ENVELOPE(-65.050,-65.050,-66.000,-66.000) |
geographic |
Norway Hoek |
geographic_facet |
Norway Hoek |
genre |
Finnmark Kirkenes Finnmark |
genre_facet |
Finnmark Kirkenes Finnmark |
op_source |
Archives of Mining Sciences volume 59, issue 3 ISSN 1689-0469 |
op_doi |
https://doi.org/10.2478/amsc-2014-0043 |
container_title |
Archives of Mining Sciences |
container_volume |
59 |
container_issue |
3 |
container_start_page |
609 |
op_container_end_page |
620 |
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1765999626367795200 |