Change search
ReferencesLink to record
Permanent link

Direct link
Hydraulisk konduktivitet i en morän: Inverkan av frys- och tiningscykler vid olika överlaster och packningsgrader
2012 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

It is well known that mining industry produces waste. Some of this material is of waste rock type. Ore containing sulphides produces waste being particularly harmful to the environment when exposed to air and water. If sulphides in the waste comes in contact with oxygen, it oxidizes and sulfur dioxide and then sulfuric acid is formed. The sulfuric acid contributes to a strong acidification (decrease in pH) in the surrounding environment, which in turn contributes to considerably faster leaching of metals. This results in elevated metal concentrations in surrounding water and an acidification of the environment. The waste rock therefore requires protection against oxygen and water. This can be done by using a soil cover. Till with low hydraulic conductivity is often used for soil cover of this type of waste rock.However, freeze and thaw cycles of this type of soil cover can result in considerable changes of the hydraulic conductivity. In northern locations this is of special concern due to climatic conditions. For a soil cover to work properly the hydraulic conductivity of the soil should not exceed 1,5x10-7 m/s.The work presented in this thesis has the purpose to investigate how the hydraulic conductivity changes with repeated freeze and thaw cycles for a given till, which is meant to be used for soil cover of the waste rock in New Boliden mine at Aitik.To investigate how the hydraulic conductivity changes upon freezing and thawing, the till has been analyzed in the laboratory. Routine experiments and hydraulic conductivity tests have been carried out. In addition to this, attempts have been made to optimize freezing times and gradients for the laboratory arrangement used for the tests of the hydraulic conductivity.The results show, that the till is multi-graded, gravel, silty, sand till.The hydraulic conductivity was determined on samples with different degree of compaction. The results show that the samples with low degree of compaction, before freezing and thawing, were compacted due to freeze/thaw. This is a consequence of consolidation effects caused in the material due to freeze/thaw in combination with the overburden acting on the sample. Samples being well compacted, with a high degree of compaction, did not show any effects due to freeze/thaw. Here neither loosing nor compaction was noticed. This means that the actual soil can be compacted to a void ratio of 0,16 without any effects of freeze/thaw.The hydraulic conductivity varies very little between the different test series and the evaluated value is never exceeding 1,5x10-7 m/s. As a consequence, it can be concluded that the tested material can be used as a soil cover for the waste rock deposits.In addition, it is noticed that there is a very small difference between the determined final hydraulic conductivity values for different degree of compaction of the samples. This is explained by general material properties. The compaction work in future should however have the goal to produce 100% of compaction.

Place, publisher, year, edition, pages
Keyword [en]
Keyword [sv]
Teknik, Hydraulisk konduktivitet, Permeabilitet, Övertäckning, Förorenat gråberg, Fryscykel, Tiningscykel
URN: urn:nbn:se:ltu:diva-55045Local ID: bf46843e-1994-4423-ac09-752938b4ff79OAI: diva2:1028426
Subject / course
Student thesis, at least 30 credits
Educational program
Civil Engineering, master's level
Validerat; 20120618 (anonymous)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

Open Access in DiVA

fulltext(3674 kB)0 downloads
File information
File name FULLTEXT02.pdfFile size 3674 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Svensson, Jimmie

Search outside of DiVA

GoogleGoogle Scholar
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

ReferencesLink to record
Permanent link

Direct link