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Surface paste disposal (SPD) technology has been investigated recently to solve the geotechnical (tailings dam failure) and geochemical (acid mine drainage formation) problems relating to tailings disposal. The tailings dam accidents occurred in the last few years have expedited the researches to search for safer tailings disposal methods in mining industry. The aim of this study is to investigate which parameters affect the geotechnical and geochemical stability of sulphidic paste tailings as SPD. The pH, EC and crack intensity of paste tailings placed in layers were measured to observe how the parameters affect their stability. In this study, it can be seen that solid concentration of the paste material increases above ~80 wt.%, and its shear strength is above 20 kPa. In addition, the pH values reduced from 7.4 to 6.6 and the EC values increased from 2.9 to 3.3 mS/cm in seepage water of the paste layers. According to these values, it can be said that there is a very low environmental risk using the SPD. Results showed the applicability of the SPD method by obtaining geochemical and geotechnical stability. [ABSTRACT FROM AUTHOR]

Surface paste disposal method can be used to minimize environmental risks during storage of mine process tailings. There are some researches and industrial applications which prove success of the method. The surface paste disposal of mineral process tailings obtained from a Pb-Zn underground mine was simulated considering mine site conditions at laboratory scale in the study. The paste material was stored in the cabin/container layer by layer, and then, the cracks occurred after the paste formation of each layer were analyzed by image process. Meanwhile, leachate water collected from the bottom of the cabin was subjected to electrical conductivity (EC) analysis. Furthermore, the wetting-drying process was conducted to simulate the climatic conditions of the region. Additionally, some physical and geochemical parameters such as matric suction, volumetric water content, and oxygen consumption of the paste material were obtained using sensors displaced into different layers. The results of the crack analysis for each layer showed that the cracks intensity increased at lower layers. Moreover, the crack intensity and EC values of each layer showed a similar trend, and the crack intensity increased almost five times during the wetting-drying tests. The measured values of the parameters obtained from the tests indicated that the deposited paste material can be stabile during the deposition over the years under the climatic conditions of the region. [ABSTRACT FROM AUTHOR]