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Publikationer (10 of 113) Visa alla publikationer
Jones, T., Nordlund, E. & Wettainen, T. (2019). Mining-Induced Deformation in the Malmberget Mine. Rock Mechanics and Rock Engineering, 52(6), 1903-1916
Öppna denna publikation i ny flik eller fönster >>Mining-Induced Deformation in the Malmberget Mine
2019 (Engelska)Ingår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 52, nr 6, s. 1903-1916Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The Norra Alliansen orebody of the Malmberget sublevel caving mine consists of iron ore interspersed with biotite schist and granitic inclusions. The schist is squeezed between the ore and the host rock and in direct contact with the ore along the majority of the length of the footwall. The schist exhibits high deformation when exposed to stress. SMART cable bolt roof deformation measurements are re-analyzed to draw conclusions regarding the patterns of deformation in the mine. Each bolt’s head is placed at the origin of a spherical coordinate system and the radius and inclination angle between the bolt and every production blast occurring during the bolt’s recorded lifetime are calculated. The deformation experienced by each instrument is investigated by comparing the long-term recorded movements with the developed geometric variables. Patterns of deformation magnitude and rate are found with respect to production-blast distance and inclination angle, instrument location, rock quality designation, and likely mining-induced stresses. Results show that deformation magnitude tends to be higher when driven by production blasting occurring on the production level above the instrumentation when accounting for the effects of distance, but average deformation magnitude for very-near production blasts tends to be higher than that for production blasts occurring directly above the instrument. Correlations also exist between the measured RQD, estimated rockmass parameters, and the measured deformation. Empirical evidence allows the identification of six scenarios which account for 91% of the recorded high-deformation-rate events. These scenarios help determine which production activities are most likely to cause high deformation rates.

Ort, förlag, år, upplaga, sidor
Springer, 2019
Nyckelord
Roof deformation, Mining-induced deformation, Sublevel caving, Instrumented bolts, Mining, Ground control
Nationell ämneskategori
Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-72687 (URN)10.1007/s00603-018-1716-6 (DOI)000468991100019 ()2-s2.0-85059776177 (Scopus ID)
Anmärkning

Validerad;2019;Nivå 2;2019-06-11 (johcin)

Tillgänglig från: 2019-01-25 Skapad: 2019-01-25 Senast uppdaterad: 2019-06-20Bibliografiskt granskad
Zhang, P., Nordlund, E., Swan, G. & Yi, C. (2019). Velocity Amplification of Seismic Waves Through Parallel Fractures Near a Free Surface in Fractured Rock: A Theoretical Study. Rock Mechanics and Rock Engineering, 52(1), 199-213
Öppna denna publikation i ny flik eller fönster >>Velocity Amplification of Seismic Waves Through Parallel Fractures Near a Free Surface in Fractured Rock: A Theoretical Study
2019 (Engelska)Ingår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 52, nr 1, s. 199-213Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

To determine the dynamic demand for support design under rockburst conditions, one of the most important issues is the prediction of ground motion parameters at the site of interest. Field monitoring has shown that the peak ground motion at the surface of an excavation in fractured rock is preferentially amplified compared to the motion in solid rock at a similar distance from the source. However, the traditional scaling laws used in rock support design do not account for the effect of free surface (excavation) and fracturing of rock. Recent studies have shown that high ground motion might be generated when a seismic wave crosses through fractures near a free surface in fractured rocks which is very complex and is not well understood. In this paper, particle velocity amplification was theoretically studied by investigating the dynamic interaction between seismic wave and multiple fractures near a free surface using the method of characteristics and the displacement discontinuity model. A harmonic load was applied on a model with a fractured zone near a free surface to investigate this phenomenon. After the harmonic wave propagated normally through multiple parallel fractures, the velocity amplification factor (VAF) was calculated as a function of the ratio of the magnitude of the peak particle velocity at the free surface of the model to the peak input velocity. The VAF can be as high as 3.77 and varies depending on the state of the fractured rock and the characteristics of the seismic wave. Parameter studies were conducted to investigate the effects of seismic load and multiple fractures on wave propagation, especially in terms of the wave frequency, the fracture spacing, the number of fractures and the stiffness of fractures. The results have proved that the interaction of the seismic wave and multiple fractures near the free surface strongly influences the ground motion. Quantitative relationships between the various influential factors and the corresponding VAF were developed. It is anticipated that such relationships can provide criteria to improve the current design procedures and help mining engineers to improve their rock support practice for rockburst-prone areas.

Ort, förlag, år, upplaga, sidor
Vienna: Springer, 2019
Nationell ämneskategori
Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-70965 (URN)10.1007/s00603-018-1589-8 (DOI)000456673000013 ()2-s2.0-85053438929 (Scopus ID)
Anmärkning

Validerad;2019;Nivå 2;2019-02-25 (inah)

Tillgänglig från: 2018-09-25 Skapad: 2018-09-25 Senast uppdaterad: 2019-04-24Bibliografiskt granskad
Petropoulos, N., Wimmer, M., Johansson, D. & Nordlund, E. (2018). Compaction of confining materials in pillar blast tests. Rock Mechanics and Rock Engineering, 51(6), 1907-1919
Öppna denna publikation i ny flik eller fönster >>Compaction of confining materials in pillar blast tests
2018 (Engelska)Ingår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 51, nr 6, s. 1907-1919Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Two confined pillar tests were conducted at the Kiirunavaara mine to investigate the degree of compaction of three materials, i.e., 0–32-mm backfilled material, a blend of ore and waste material and caved material. Two blastholes were drilled parallel to each pillar wall, and several measurement holes were drilled in between the blastholes through each pillar. Both the measurement holes and backfilled materials, except the caved material, were instrumented. Two types of measurements were taken: dynamic measurements with accelerometers, and static measurements which considered the location of the instrumentation pre- and post-blast. Dynamic measurements involved the burden movement and the confining material behavior, and static measurements contained the final location of sensors inside and the angle of repose of the confining material. The results showed that the size distribution of the confining material affects its behavior under dynamic loading. The backfilled materials showed an apparent cohesion forming an agglomeration on the surface of the blasted burden. The burden moved as one slab due to simultaneous detonation. A gap was formed between the blasted burden and the new face. This gap was partially filled with burden erosion material which was finer fragmented than the blasted burden material.

Ort, förlag, år, upplaga, sidor
Springer, 2018
Nyckelord
Compaction, burden movement, pillar tests, sublevel caving, confined blasting
Nationell ämneskategori
Mineral- och gruvteknik Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-67850 (URN)10.1007/s00603-018-1447-8 (DOI)000433195900016 ()2-s2.0-85047517598 (Scopus ID)
Projekt
Improved understanding of sublevel blasting – Determination of the extent of the compacted zone, its properties and the effects on caving
Anmärkning

Validerad;2018;Nivå 2;2018-06-01 (rokbeg)

Tillgänglig från: 2018-03-06 Skapad: 2018-03-06 Senast uppdaterad: 2018-08-27Bibliografiskt granskad
Petropoulos, N., Mihaylov, D., Johansson, D. & Nordlund, E. (2017). A Suggested Method for the Study of Crushed Aggregate Response to Dynamic Compaction. The Electronic journal of geotechnical engineering, 22(02), 387-406
Öppna denna publikation i ny flik eller fönster >>A Suggested Method for the Study of Crushed Aggregate Response to Dynamic Compaction
2017 (Engelska)Ingår i: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 22, nr 02, s. 387-406Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Soil improvement by dynamic compaction has been extensively used all around the world in large civil engineering projects. Limited number of laboratory tests has been conducted to study the behavior of soil material under dynamic loading. A suggested method is presented in this paper which includes a new laboratory apparatus and experimental procedure as well as data analysis. The suggested impact machine is a drop hammer type machine, it can host up to 37.5 mm particle size in a coarse-grained aggregate matrix independent of its conditions, i.e. saturated or unsaturated, it is also flexible in terms of weight and size of the drop hammer and the mold. The machine is equipped with accelerometers for continuous monitoring of the sample’s behavior during impact. The experimental procedure shows the steps for conducting consistent dynamic compaction tests. It also describes how the measurements should be conducted. These measured quantities correspond to key parameters such as density, angle of repose and compaction. Finally, a case example demonstrates the function of the machine and the analysis of the recorded data.

Ort, förlag, år, upplaga, sidor
Mete Öner, 2017
Nyckelord
Dynamic compaction, impact tests, experimental apparatus, soil behavior, confined blasting
Nationell ämneskategori
Mineral- och gruvteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-61643 (URN)
Projekt
Improved understanding of sublevel blasting – Determination of the extent of the compacted zone, its properties and the effects on caving
Anmärkning

Validerad; 2017; Nivå 1; 2017-02-15 (andbra)

Tillgänglig från: 2017-01-26 Skapad: 2017-01-26 Senast uppdaterad: 2018-11-20Bibliografiskt granskad
Petropoulos, N., Johansson, D. & Nordlund, E. (2017). Crushed aggregate response upon impact in dry and wet conditions. Journal of Earth Sciences and Geotechnical Engineering, 7(3), 1-22
Öppna denna publikation i ny flik eller fönster >>Crushed aggregate response upon impact in dry and wet conditions
2017 (Engelska)Ingår i: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 7, nr 3, s. 1-22Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This paper presents results from a series of impact tests upon coarse-grained crushed aggregate. The material has been evaluated for two conditions, i.e. dry and wet (pendular state). Three main sets of test configurations were used with respect to compactive effort (low, medium and high) which was defined by the impact velocity of a drop hammer. Three accelerometers were installed in an impact machine to measure deceleration of the drop hammer and accelerations in the tested material at three different locations. The studied parameters were density, compaction, angle of repose, critical angle and particle size distribution. The results showed that the wet material gives larger density as well as critical angle. However, there was no discernible change in particle size distribution.

Ort, förlag, år, upplaga, sidor
ScienPress Ltd, 2017
Nyckelord
Impact tests, granular material, aggregate, compaction, wet material, dry material
Nationell ämneskategori
Mineral- och gruvteknik Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-62844 (URN)
Projekt
Improved understanding of sublevel blasting – Determination of the extent of the compacted zone, its properties and the effects on caving
Anmärkning

Validerad; 2017; Nivå 1; 2017-04-04 (andbra)

Tillgänglig från: 2017-04-03 Skapad: 2017-04-03 Senast uppdaterad: 2018-11-15Bibliografiskt granskad
Saiang, D. & Nordlund, E. (2017). Numerical Analyses of Field Monitoring in Stope J10-3 at Kristineberg Mine. Luleå: Luleå University of Technology
Öppna denna publikation i ny flik eller fönster >>Numerical Analyses of Field Monitoring in Stope J10-3 at Kristineberg Mine
2017 (Engelska)Rapport (Refereegranskat)
Ort, förlag, år, upplaga, sidor
Luleå: Luleå University of Technology, 2017. s. 61
Serie
Teknisk rapport / Luleå tekniska universitet, ISSN 1402-1536
Nationell ämneskategori
Teknik och teknologier Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och Berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-62761 (URN)978-91-7583-857-1 (ISBN)
Tillgänglig från: 2017-03-28 Skapad: 2017-03-28 Senast uppdaterad: 2018-04-16Bibliografiskt granskad
Chen, G., Li, X., Zhang, P., Nordlund, E. & Dong, L. (2017). Optimization of tunnel support parameters with consideration of seismic wave radiation pattern in the fault-slip burst. Journal of Mining and Safety Engineering, 34(4), 715-722
Öppna denna publikation i ny flik eller fönster >>Optimization of tunnel support parameters with consideration of seismic wave radiation pattern in the fault-slip burst
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2017 (Engelska)Ingår i: Journal of Mining and Safety Engineering, ISSN 1673-3363, Vol. 34, nr 4, s. 715-722Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

As the underground mining extends gradually towards depth, more and more seismic events induced by fault slip occur and cause great damages, which have become a severe potential threat to mining safety. In view of the plane strain problems, through the three dimensional discrete model established, comparison and analysis was carried out between the equivalent calculation of plane strain in 3D model and a 2D discrete model. The results have shown that the research model developed to simulate the propagation of seismic wave in 3D is feasible and applicable. The study of the effect of radiation pattern on seismic propagation revealed and tested the direction of P-and S-wave propagation, which presents high consistency to double couple model of the fault slip. On this basis, the comparison with the design scaling law formulas proposed by Kaiser and associates finds that the existing design scaling law does not totally satisfy the demand of practical engineering. Numerical calculation and analysis with the three dimensional discrete model can further optimize the support parameters, provide better service for system design of mining support, and ensure the safety and high efficiency in mining.

Ort, förlag, år, upplaga, sidor
China University of Mining and Technology, 2017
Nationell ämneskategori
Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-65467 (URN)10.13545/j.cnki.jmse.2017.04.016 (DOI)2-s2.0-85027967448 (Scopus ID)
Anmärkning

Chinese journal title: Caikuang yu Anquan Gongcheng Xuebao

Tillgänglig från: 2017-09-04 Skapad: 2017-09-04 Senast uppdaterad: 2019-04-23Bibliografiskt granskad
Nordström, E., Dineva, S. & Nordlund, E. (2017). Source parameters of seismic events potentially associated with damage in block 33/34 of the Kiirunavaara mine (Sweden). Acta Geophysica, 65(6), 1229-1242
Öppna denna publikation i ny flik eller fönster >>Source parameters of seismic events potentially associated with damage in block 33/34 of the Kiirunavaara mine (Sweden)
2017 (Engelska)Ingår i: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 65, nr 6, s. 1229-1242Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Forty-six mining-induced seismic events with moment magnitude between −1.2 and 2.1 that possibly caused damage were studied. The events occurred between 2008 and 2013 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope −2). The radiated energy for the studied events varied from 4.7 × 10−1 to 3.8 × 107 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 102 to 1.1 × 106 Pa, energy ratio (Es/Ep) from 1.2 to 126, and apparent volume from 1.8 × 103 to 1.1 × 107 m3. 90% of the events were located in the footwall, close to the ore contact. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the Es/Ep ratio (>10 or <10). Out of 46 events 15 events were classified as NS located almost in the whole range between 840 and 1360 m, including many events below the production. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The energy and the apparent stress were found to be three times larger for FS events than for NS events.

Ort, förlag, år, upplaga, sidor
Springer, 2017
Nyckelord
Mining-induced seismic events, Source parameters, Hypocentre locations, Shear and non-shear mechanisms
Nationell ämneskategori
Naturvetenskap Teknik och teknologier Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och Berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-66726 (URN)10.1007/s11600-017-0066-1 (DOI)000418097100012 ()
Forskningsfinansiär
VINNOVA
Anmärkning

Validerad;2018;Nivå 2;2017-12-21 (andbra)

Tillgänglig från: 2017-11-23 Skapad: 2017-11-23 Senast uppdaterad: 2018-05-22Bibliografiskt granskad
Idris, M. A., Nordlund, E. & Saiang, D. (2016). Comparison of different probabilistic methods for analyzing stability of underground rock excavations. The Electronic journal of geotechnical engineering, 21(21), 6555-6585
Öppna denna publikation i ny flik eller fönster >>Comparison of different probabilistic methods for analyzing stability of underground rock excavations
2016 (Engelska)Ingår i: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 21, nr 21, s. 6555-6585Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Stability analyses of underground rock excavations are often performed using traditional deterministic methods. In deterministic methods the mean or characteristics values of the input parameters are used for the analyses. These method neglect the inherent variability of the rock mass properties in the analyses and the results could be misleading. Therefore, for a realistic stability analyses probabilistic methods, which consider the inherent variability of the rock mass properties, are considered appropriate. A number of probabilistic methods, each based on different theories and assumptions have been developed for the analysis of geotechnical problems. Geotechnical engineers must therefore choose appropriate probabilistic method to achieve a specific objective while taking into account simplicity, accuracy and time efficiency. In this study finite difference method was combined with five different probabilistic methods to analyze the stability of an underground rock excavation. The probabilistic methods considered were the Point Estimate Method (PEM), the Response Surface Method (RSM), the Artificial Neural Network (ANN), the Monte Carlos Simulation (MCS), and the Strength Classification Method (SCM). The results and the relative merits of the methods were compared. Also the general advantages of the probabilistic method over the deterministic method were discussed. Though the methods presented in this study are not exhaustive, the results of this study will assist in the choice of appropriate probabilistic methods for the analysis of underground rock excavations. 

Ort, förlag, år, upplaga, sidor
Mete Öner, 2016
Nationell ämneskategori
Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-59926 (URN)2-s2.0-84992509213 (Scopus ID)
Anmärkning

Validerad; 2016; Nivå 2; 2016-11-14 (andbra)

Tillgänglig från: 2016-10-24 Skapad: 2016-10-24 Senast uppdaterad: 2018-11-23Bibliografiskt granskad
Svartsjaern, M., Saiang, D., Nordlund, E. & Eitzenberger, A. (2016). Conceptual Numerical Modeling of Large-Scale Footwall Behavior at the Kiirunavaara Mine, and Implications for Deformation Monitoring (ed.). Paper presented at . Rock Mechanics and Rock Engineering, 49(3), 943-960
Öppna denna publikation i ny flik eller fönster >>Conceptual Numerical Modeling of Large-Scale Footwall Behavior at the Kiirunavaara Mine, and Implications for Deformation Monitoring
2016 (Engelska)Ingår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 49, nr 3, s. 943-960Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Over the last 30 years the Kiirunavaara mine has experienced a slow but progressive fracturing and movement in the footwall rock mass which is directly related to the sublevel caving (SLC) method utilized by Luossavaara-Kiirunavaara Aktiebolag (LKAB). As part of an on-going work, this paper focuses on describing and explaining a likely evolution path of large-scale fracturing in the Kiirunavaara footwall. The trace of this fracturing was based on a series of damage mapping campaigns carried out over the last two years, accompanied by numerical modelling. Data collected from the damage mapping between mine levels 320 and 907 m was used to create a 3D surface representing a conceptual boundary for the extent of the damaged volume. The extent boundary surface was used as the basis for calibrating conceptual numerical models created in UDEC. The mapping data, in combination with the numerical models, indicated a plausible evolution path of the footwall fracturing that was subsequently described. Between levels 320 and 740 m the extent of fracturing into the footwall appears to be controlled by natural pre-existing discontinuities, while below 740 m there are indications of a curved shear or step-path failure. The step-path is hypothesised to be activated by rock mass heave into the SLC zone above the current extraction level. Above the 320 m level the fracturing seems to intersect a sub-vertical structure that daylights in the old open pit slope. Identification of these probable damage mechanisms was an important step in order to determine the requirements for a monitoring system for tracking footwall damage. This paper describes the background work for design of the system currently being installed.

Nationell ämneskategori
Annan samhällsbyggnadsteknik
Forskningsämne
Gruv- och Berganläggningsteknik
Identifikatorer
urn:nbn:se:ltu:diva-10894 (URN)10.1007/s00603-015-0750-x (DOI)000371313300014 ()2-s2.0-84959154826 (Scopus ID)9c57e456-e493-4fed-a105-98f1373c0678 (Lokalt ID)9c57e456-e493-4fed-a105-98f1373c0678 (Arkivnummer)9c57e456-e493-4fed-a105-98f1373c0678 (OAI)
Anmärkning
Validerad; 2016; Nivå 2; 20150527 (miknil)Tillgänglig från: 2016-09-29 Skapad: 2016-09-29 Senast uppdaterad: 2018-07-10Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-9766-0106

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