Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Mechanical Behavior of Tailings: Laboratory Tests from a Swedish Tailings Dam
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering. (Soil Mechanics)ORCID iD: 0000-0002-5987-0006
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Tailings is leftover material from mining industry and is produced in huge quantities approximately 70-99% of the ore production.  Tailings material is stored as impoundments by constructing tailings dams which are often constructed with tailings material itself. Tailings are artificial material and the mechanical behavior of tailings material upon loading is different as compared to natural soil materials. There are number of dam failures reported every year which has severe impact on inhabitants and environment nearby. Considering the failures of tailings dams and consequences there is a need to understand the tailings material in depth for safe existence of these dams. The confident dam design can assure the safe existence of tailings dams for long term as these dams are presumed to function for generations to come. The material properties in tailings dams can change during operation due to raising of new layer. Raised new layer can change stress level, which in turn may change the material properties in terms of strength, pore pressures, grain sizes etc. Today mostly tailings dam are designed by performing analysis for safety for existing and future rasings as well. These analyses are based upon a for certain factor of safety. Not very much can be done with design and analysis for tailings material if the material is not described very well. Understanding of tailings material in depth can provide help for detailed material parameters which later can be used in safety assessment for future raising and changed conditions in dam.

This study presents the work carried out on tailings material from a Swedish tailings dam. The study is conducted on undisturbed and disturbed tailings material. The undisturbed tests are carried out to understand material properties as per in-situ conditions. Whereas disturbed materials are used to created different materials with different particles sizes. Initially in this study the basic properties of tailings materials are studied e.g. specific gravity, phase relationships, particle sizes, particle shapes and shear behavior on collected samples at various depths. During direct shear tests, the unexpected vertical height reductions were observed, these results are presented in this study. The comparison of strength parameters by direct shear and triaxial tests on material from various depths is also done and presented.

Based on results from direct shear, triaxial and oedometer tests on uniform sized tailings material; the evaluation of primary and secondary deformations and particle breakage and effect of vertical loads is also carried out and presented. The study also includes the comparison of strength parameters for each particles size. The breakage of particles is analyzed by sieving the material after direct shear tests followed by a particle shape study. The effect of deposition on shear strength parameters is also studied by construction of samples with different angle of deposition of material. The strength parameters of uniform sized particles in triaxial tests are also evaluated and discussed.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017.
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keyword [en]
Tailings dams, Tailings, Mechanical Behavior, Oedometer, Direct Shear, Triaxial, Shear strength
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
URN: urn:nbn:se:ltu:diva-62534ISBN: 978-91-7583-849-6 (print)ISBN: 978-91-7583-850-2 (electronic)OAI: oai:DiVA.org:ltu-62534DiVA: diva2:1082434
Public defence
2017-04-25, F1031, Luleå tekninska universitet, Luleå, 10:00 (English)
Available from: 2017-03-20 Created: 2017-03-16 Last updated: 2017-05-11Bibliographically approved
List of papers
1. Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings
Open this publication in new window or tab >>Effect of Particle Size On Mechanical Properties and Particle Breakage of Tailings
2017 (English)In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010Article in journal (Refereed) Submitted
Abstract [en]

Tailings material can have different material properties depending upon the type of ore and ore refining process and particle size distribution. Tailings dams are constructed as walk away solutions. Staged construction of tailings dams may lead to breakage of particles in subsequent layers resulting in change in particle sizes of material. This may lead to change in strength parameters upon change in particle sizes. This paper presents the direct shear tests performed on tailings material from a tailings dam. Remolded samples were manufactured in laboratory. The tailings material is separated in to four different particle sizes i.e.1-0.5mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The tests are performed on different normal stress levels as 50, 100, 150, 300 and 500kPa.The strength parameters are evaluated for each particle size and compared with said particle sizes. In order to study the effect of deposition, the tests are also performed on same material deposited in vertical and horizontal direction. This paper also describes the study of breakage of particles during direct shear tests by sieving the material at the end of each test. 

Keyword
Direct Simple Shear, Tailings Dams, Tailings Material, Particle Breakage, Vertical Height
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-62681 (URN)
Available from: 2017-03-25 Created: 2017-03-25 Last updated: 2017-06-27
2. Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests
Open this publication in new window or tab >>Mechanical Behavior of Uniformed Tailings Material in Triaxial Tests
2017 (English)In: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 22, no 06, 1717-1730 p.Article in journal (Refereed) Published
Abstract [en]

Tailings dams are raised with time depending upon rate of generation of waste. A tailings dam can contain different particle sized materials within its dam body. The newly raised embankment in a tailings dam can be considered as vertical load being applied on subsequent layer. The applied loads can cause deformations and breakage of particles. The particle breakage can then lead to a skeleton with new particle size particles and hence can lead to new material properties. This paper provides the results from triaxial tests conducted on uniformed particle sizes as, 0.5mm-0.25mm, 0.25mm-0.125mm and 0.125mm-0.063mm.  The tests are performed at various effective radial stresses. The results are evaluated and compared with each particle size. The results include stress-strain and volumetric behavior during shearing, the effective stress ratio and stress-dilatancy plot. The friction angles are also evaluated and compared with different particle sized specimens. It was found that effective stress ratios were slightly higher when tests were performed at lower confining stresses and vice versa. It was also observed that particle size did not show any effect of friction angles.

Keyword
Shear Strength, Triaxial Tests, Tailings Dams, Mechanical Properties, Tailings
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-62645 (URN)
Note

Validerad; 2017; Nivå 1; 2017-04-03 (andbra)

Available from: 2017-03-23 Created: 2017-03-23 Last updated: 2017-06-27Bibliographically approved
3. Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment: Results from Direct Shear Tests
Open this publication in new window or tab >>Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment: Results from Direct Shear Tests
2014 (English)In: The Electronic journal of geotechnical engineering, ISSN 1089-3032, E-ISSN 1089-3032, Vol. 19, no Z, 9023-9039 p.Article in journal (Refereed) Published
Abstract [en]

The shear strength of tailings can vary depending upon the type of ore and method of construction. Tailings dams may possess loose layers in subsequent layers, which may have low shear strength. Since the tailings dams are made-up to last for longer times, the strength parameters and material behaviors are essential to understand, especially potential for static liquefaction in loose layers. This article presents the results from direct shear tests performed on samples from loose layer of a tailings dam. Both drained and undrained tests are carried out. The results indicated the strain hardening behavior in tailings material which indicates loose condition. The shear strength was found to be relatively low as compared to typical values of tailings in literature. A contractant volume behavior was observed for all the tests. During shear tests the vertical height reductions in samples were observed. These changes were significantly increased after peak shear followed by slight increment in pore pressure along shearing angle. The reasons for these height changes are not fully known, but may be a rearrangement in skeleton or breakage of particles during shear which needs further investigative studies.

National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-12353 (URN)b7a0913c-f7ac-4c51-9f46-75f928316ffe (Local ID)b7a0913c-f7ac-4c51-9f46-75f928316ffe (Archive number)b7a0913c-f7ac-4c51-9f46-75f928316ffe (OAI)
Note
Validerad; 2014; 20141008 (riabha)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-06-27Bibliographically approved
4. Basic description of tailings from Aitik focusing on mechanical behavior
Open this publication in new window or tab >>Basic description of tailings from Aitik focusing on mechanical behavior
Show others...
2013 (English)In: International Journal of Emerging Technology and Advanced Engineering, ISSN 2250-2459, E-ISSN 2250-2459, Vol. 3, no 12, 65-69 p.Article in journal (Refereed) Published
Abstract [en]

Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct shear behavior are presented in this article. The results showed that particles size decreases along depth from surface for collected sample locations. The angularity of the particles increases as the grain size decreases. Vertical height reduction was observed during shearing of samples by direct shear tests.

National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-15712 (URN)f429931a-e613-4ae6-987d-fd62b8e75fd7 (Local ID)f429931a-e613-4ae6-987d-fd62b8e75fd7 (Archive number)f429931a-e613-4ae6-987d-fd62b8e75fd7 (OAI)
Note
Godkänd; 2013; 20131219 (riabha)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-06-27Bibliographically approved
5. Evaluation Of Primary And Secondary Deformations and Particle Breakage of Tailings
Open this publication in new window or tab >>Evaluation Of Primary And Secondary Deformations and Particle Breakage of Tailings
2015 (English)In: From Fundamentals to Applications in Geotechnics: Proceedings of the 15th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 15–18 November 2015, Buenos Aires, Argentina / [ed] Diego Manzanal; Alejo O. Sfriso, IOS Press, 2015, 2481-2488 p.Conference paper, (Refereed)
Abstract [en]

Tailings are the waste product of mining which is left over after extraction of materials of interest. Tailings material may possess different material properties depending upon type of ore and method of concentration. Sometimes the tailings material itself is used in construction of tailings dams and tailings dams are constructed to withstand for long times. A tailing dam can be exposed to settlements due to incremental load as these dams are raised in stages. Increasing load with time may also lead to particle breakage. This article presents the results from oedometer tests conducted on tailings materials. The study includes the stress-deformation behavior and particle breakage of tailings material of different gradations upon application of incremental loads in oedometer tests. The samples were collected from different sections of tailings dam from Sweden. Remolded samples were manufactured in laboratory as four batches of particle sizes i.e. 1-0.5 mm, 0.5-0.25mm, 0.25-0.125mm and 0.125-0.063mm. The results are analyzed from tested samples at different stress levels and compared with different particle sizes. The breakage of particles of each batch is analyzed by sieving the specimens after oedometer tests. The results are evaluated in terms of primary and secondary deformations. The primary and secondary deformations are also compared with different particle sized specimens.

Place, publisher, year, edition, pages
IOS Press, 2015
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-39334 (URN)10.3233/978-1-61499-603-3-2481 (DOI)000380938803005 ()e060c23f-49e3-4d6f-a2ed-0c995c35a833 (Local ID)978-1-61499-602-6 (ISBN)978-1-61499-603-3 (ISBN)e060c23f-49e3-4d6f-a2ed-0c995c35a833 (Archive number)e060c23f-49e3-4d6f-a2ed-0c995c35a833 (OAI)
Conference
Pan-American Conference on Soil Mechanics and Geotechnical Engineering : 15/11/2015 - 18/11/2015
Note

Validerad; 2016; Nivå 1; 2016-10-10 (andbra)

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-06-27Bibliographically approved
6. Shear Strength in Uniformed Sized Tailing Particles
Open this publication in new window or tab >>Shear Strength in Uniformed Sized Tailing Particles
(English)In: International Journal of Geotechnical Engineering, ISSN 1938-6362, E-ISSN 1939-7879Article in journal (Refereed) Submitted
Abstract [en]

Mining industry provides mineral to the modern society. Minerals are indispensable raw materials for commodities. A by-product of the mineral extraction is the mine waste also called tailings. Tailings are safety storage in tailing dams. Tailings dams troughs the history had had incidents and failures. Economic, environmental and social consequences of a tailing dam failure could be devastating. Soil strength is given by the consolidation, particle shape, stresses path, water content, hydraulic conductivity among other factors. Change on these factors produces changes in the soil strength. The development of economical and fast tests could improve the safety of the tailings deposits. Drained direct shear tests using uniformed graded tailing particles were performed. Three different size ranges 0.25, 0.125 and 0.063mm were used. Effect of particle size on shear strength and the effect of shearing on the tailing particles were studied. Normal consolidation pressure, void ratio, particle size and particle shape were monitored properties. Strength of the tailings was related with the monitored properties to suggest four empirical relations, two of them base in the morphology of the particle and two bases in the angularity. Results have shown that particle elongation diminishes the tailings strength but the angularity increases the strength. Particle size results are ambiguous and seem to be more related with the shape descriptor.

Keyword
tailings dams, direct shear tests, tailings, particle breakage, particle shapes
National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-61802 (URN)
Available from: 2017-02-03 Created: 2017-02-03 Last updated: 2017-06-27
7. Effect of vertical load on tailings particles
Open this publication in new window or tab >>Effect of vertical load on tailings particles
2016 (English)In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 6, no 2, 115-129 p.Article in journal (Refereed) Published
Abstract [en]

Tailing dams could store hundreds, thousands or millions of cubic meters of tailings result of the mining extractive industry. Mechanical behavior of this man-made soil should be known in order to maintain a safe storage. Dykes rise up to form the dams and they are buildup with the same tailing material especially in the upstream method using the coarse part. The study uses oedometer classical test to determine the load effect over tailing coarse particles. Tailings are site specific and so its characteristics. It is necessary to understand the tailings degradations to achieve safe impounds. The study comprises four samples of one range-size tailing particles (e.g. 1-0.5, 0.5-0.25, 0.25-0.125, 0.125-0.063mm) subject to vertical load in traditional oedometers. Vertical load effects are measured using two dimensional image analysis and sieving. Results show that 0.063mm sample is the only one that has change in shape with low breakage (<1%) while the rest of the sizes have no shape change but high breakage is present especially in fraction 0.5mm. Settlements also are more pronounced in coarse fractions 0.5 and 0.25mm.

National Category
Geotechnical Engineering
Research subject
Soil Mechanics
Identifiers
urn:nbn:se:ltu:diva-9274 (URN)7dd7b397-4584-4d2f-a6fe-c34846daea63 (Local ID)7dd7b397-4584-4d2f-a6fe-c34846daea63 (Archive number)7dd7b397-4584-4d2f-a6fe-c34846daea63 (OAI)
Note

Validerad; 2016; Nivå 1; 2016-11-22 (inah)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-06-27Bibliographically approved

Open Access in DiVA

fulltext(10636 kB)56 downloads
File information
File name FULLTEXT02.pdfFile size 10636 kBChecksum SHA-512
05a49e7acbf56302683eaecab66bc95d8aa0a2cef160d5e756bfbd104d6202a077b1be04bdcb2282eefe10ecf4a20a873fa5e0499e995a8a6a3a44d65968672f
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Bhanbhro, Riaz
By organisation
Mining and Geotechnical Engineering
Geotechnical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 132 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 482 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf