Effects of Solar Energy on the Mechanical Properties of Tailings in Tailings Dams

Abstract

Mine tailings are the most common materials that are used in construction of tailings dams. Due to high level of environmental hazard and serious consequences that are associated with tailings dam failure, proper design of tailings dams is an important factor in mining industry. Water level fluctuation, change in permeability of dam foundation, seismic loads, and excessive settlements are the most common reasons of failure, particularly in upstream type tailings dams. Due to low shear strength of wet tailings, drying of tailing material is very common in practice during the dam construction. In hot climate, the received solar energy at the soil surface converts to soil heat flux, air heat flux, and evaporation energy. The evaporation energy generates matric suction in the tailings fabric which can potentially induce apparent cohesion and consequently improve the shear strength of tailing materials. The soil-water characteristic curve is used to correlate the volumetric water content of the soil with matric suction. In this study, an algorithm is proposed to determine the amount of apparent cohesion, induced by sunlight effects on the stability of tailing dams. The proposed algorithm is employed in stability analysis of Barnick Mercur tailings dam, which is a 280 foot high dam in a gold mine in Utah. The obtained results indicate that taking advantage of solar energy to enhance the geomechanical properties of tailing materials can improve the stability of tailings dam.