Strength Properties of Sedimentary Tailings with Different Contents of Fine Particles and the Seepage Damage Risk of Tailings Dams

Breaches of tailings dams have had catastrophic consequences in the mining industry worldwide. Therefore, the characteristics of tailings and their effects on the stability of tailings dams need to be investigated. In this paper, the mechanical properties of uniform tailings and smaller sedimentary tailings are analyzed in laboratory testing. The critical hydraulic gradient of tailings is explored and a tailings dam model is constructed. The results of testing indicate that the strength of tailings gradually decreases with an increase in the content of fine particles smaller than 0.075 mm. The critical content of fine particles is 35% fine particles smaller than 0.075 mm. The strength, cohesion, and internal friction angle of uniform tailings are greater than those of smaller sedimentary tailings. The critical hydraulic gradient decreases with an increase in the content of fine particles smaller than 0.075 mm, and the critical content of fine particles is again approximately 35%. However, the critical hydraulic gradient of smaller sedimentary tailings is higher than that of uniform tailings. An equation is presented to calculate the critical hydraulic gradient of tailings. The seepage failure of the tailings dam can be divided into four parts. An equation is presented to calculate the critical hydraulic gradient of a tailings dam.