Mechancial Behavior of Tailings: Laboratory Tests from a Swedish Tailings Dam
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
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. 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. Today mostly limit-state analysis is performed, based upon this; a design is done for certain factor of safety (1.5). Not very much can be done with design and analysis for this type of material if the material is not described very well. Understanding of tailings material in depth can bring forward 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 based on total eight papers, out of which three papers discuss the undisturbed tailings material and five papers discuss the remolded tailings material constructed in laboratory. The first three papers describe basic properties of undisturbed tailings material collected from different layers of a tailings dam. The first paper defines basic properties which include; specific gravity, phase relationships, particle sizes, particle shapes and shear behavior. The second paper describes direct shear tests conducted on undisturbed tailings material from various depths of a tailings dam. This paper also discusses the vertical height reductions during shearing tests on tailings material. The third paper is based on results from triaxial tests carried on tailings material from soft layers of a tailings dam. This paper presents the effect of depth on strength parameters and mechanical behavior for different depths of dam section.
The fourth and fifth paper is about primary and secondary deformations and particle breakage and effect of vertical loads on particles in terms of shapes. These papers are based on results from oedometer tests on uniform sized tailings material. These tailings samples were constructed into four different sizes i.e. 1 – 0.5 mm, 0.5 – 0.25 mm, 0.25 – 0.125 mm and 0.125 – 0.063 mm.
The last three papers discuss the direct shear and triaxial tests conducted on uniform graded tailings material i.e. 1 – 0.5 mm, 0.5 – 0.25 mm, 0.25 – 0.125 mm and 0.125 – 0.063 mm. These papers include the studies of comparison 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.
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Tailings dams, Tailings, Mechanical Behavior, Oedometer, Direct Shear, Triaxial, Shear strength
Research subject Soil Mechanics
IdentifiersURN: 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