The instability of tailings dams is caused by several factors which include weather extremes, overtopping, seepage, erosion, subsidence and poor construction methods. In addition, emerging mining technologies which facilitate the extraction of minerals from low grade ores also produce higher tailings volumes of very fine particle size. Problems associated with fine grained tailings include reduced permeability and shear strength which consequently increase the risk of dam failure. The stability of tailings dams can be improved by reinforcing the impoundments with geosynthetics. A geosynthetic should only be used for tailings dam reinforcement if it has sufficient chemical resistance, strength and durability. A series of tests is therefore necessary to assess the effectiveness of reinforcing specific tailings with a given geosynthetic. In this study, interface direct shear strength tests were conducted to assess the frictional resistance between platinum mine tailings and different types of geosynthetics. Using the test results a reliability slope stability analysis was conducted. It was found that reinforcing the dam with geosynthetics permitted an increase in the height of the dam dykes and slope by a factor of 1.3 and 2.3 respectively with 0% probability of failure. This demonstrated that geosynthetics reinforced tailings dams are not only more stable but they can be constructed at the optimum geometry which fully utilizes the allocated land. Consequently, stabilizing tailings dams with geosynthetics also reduces their construction and maintenance costs.
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