Hydro-Geotechnical Study of Tailings at Aitik Mine : Emphasis on Hydraulic Conductivity of the Deposit

The main objective of this study is to characterize the tailings deposit at Aitik Mine in terms of its hydro geotechnical properties with more emphasis on hydraulic conductivity and present their vertical and horizontal distribution. In this study, relationship between each parameter has also been identified. The investigation has been done in three sections which cover approximately 3km2 of area and 4-5meters vertically. 3-5 test pits have been excavated in each section and disturbed and undisturbed samples are collected from various levels. Apart from in situ tests like balloon density, laboratory investigations have been done on the collected samples. These tests includes: Proctor compaction, particle density termination, grain size analysis, and permeability. Evaluation of existing empirical relations between grain size analysis and hydraulic conductivity were also one of the aims of this thesis work.The horizontal hydraulic conductivity has been found to have a good correlation to fine fraction and void ratio. Similar to the results of Jantzer et al (2008), the increased void ratio did not correspond to vertical hydraulic conductivity. Based on evaluation of Hazen (1911) and Chapuis et al (2003) formulas using the samples collected, conclusions have been made. Therefore, Hazen formula (1911) has given 25 and 45 times the measured values of vertical and horizontal hydraulic conductivity respectively. On the other hand, Chapuis et al (2003) has not been succeeded for prediction of hydraulic conductivity of undisturbed samples. However, it has given comparatively good prediction of hydraulic conductivity for disturbed samples which are compacted to their field dry density. Particle density, porosity and void ratio results are in agreement with the range determined by Yunxin (2001), Shamsai (2007), and Jantzer et al (2008) on different tailings deposit. Ice layers are encountered exactly above layers with higher silt and clay contents. Silty SAND is discovered to be the predominant soil type in the investigated area.Because the study was able to cover only part of the whole deposit, further detailed investigation covering the whole area and depth of the deposit is recommended to be done in the future. Additionally, monitoring and continuous measurements are important to minimize uncertainty that could be caused by seasonal tailings property changes.Validerat; 20120622 (anonymous