This paper investigates the beaching slopes of two centrally discharging tailings storage facilities (TSF). It explains the methodology for determining the beaching angles and how this information was used in modelling the remaining life. It then examines the properties of the tailings from the two facilities and discusses the effects of these properties on the beaching slopes.

The results of hydrodynamic sieving tests in which pretensioned geotextile specimens were tested using glass beads as the suspended particles are reported. Biaxial as well as uniaxial tensile loads were used. Two types of geotextile were tested, a woven slit-film polypropylene geotextile and a nonwoven needle-punched polyester geotextile. In all but one of the tests reported, the effect of a tensile load was to reduce the filtration opening size. The effect was most pronounced with the woven geotextile, where an equal biaxial load of only 8% of the minimum tensile strength of the geotextile resulted in a 28% decrease in the filtration opening size. Since all the tests resulted in a decrease in the filtration opening size, it appears unlikely that inplane tensile loads will exacerbate problems of loss of particles through a geotextile. However, it is suggested that increased problems associated with geotextile clogging and blinding can be expected. Preliminary tests in a modified permeameter on uniaxially loaded geotextile specimens in contact with a fine sand confirmed this hypothesis.

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