Application of Pb-Zn tailings for surface paste disposal: geotechnical and geochemical observations

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.