Influence of amang (Tin Tailing) on geotechnical properties of clay soil (Pengaruh amang timah terhadap sifat geoteknik tanih lempung)

摘要

Amang or tin tailing is commonly found in the vicinity of disused mining area and responsible in downgrading theudwater quality, landscape and mechanical behaviour of soils. It was generated from extraction process of separatingudvaluable metal from particular ore. This paper presents the geotechnical characteristics of amang-contaminatedudclay soil. The geotechnical properties of uncontaminated soils were studied in order to compare to that of amangcontaminatedudsoils. The base soil used in this study represents completely weathered horizon of metasedimentaryudrock. Meanwhile, tin tailing sample was taken from the disused mine at Sungai Lembing, Pahang. The geotechnicaludcharacterisations of base soil and contaminated soils were determined based on consistency index, compactionudbehaviour, hydraulic conductivity and undrained shear strength (UU tests). Contaminated soil samples were preparedudby adding 5, 10 and 20% of tailing, based on dry weigh of the studied base soil. The results from the particle sizeuddistribution analysis showed that residual soil from metasedimentary rock comprised 42.6% clay, 32.2% silt andud25.2% sand whilst tailing was dominated by 98% of sand fraction. XRD analysis indicated the presence of quartz,udkaolinite and muscovite minerals in the studied soil. The specific gravity of soil used is 2.67 and the pH is 3.88.udTailing found to have higher specific gravity of 3.37. The consistency index of contaminated soils showed that liquidudlimit, wL and plastic limit, wP decreased with the increase in the percentage of tailing added to the soil samples.udThe value of maximum dry density, ρ dry max increased while optimum moisture content decreased due to the increaseudin tailing content in soil sample. The permeability of contaminated soil also increased with the increase in tailingudcontents ranged from 19.8 cm/hr to 23.8 cm/hr. The undrained shear strength, Cu, of contaminated soil decreasedudfrom 646 kPa (5% of tailing) to 312 kPa (20% of tailing) suggesting that the presence of tailing has influenced theudgeotechnical properties on the studied soil.