Analysis of wind-driven resuspension of metal mine sludge in a tailings pond Available to Purchase

Shallow water covers, typically less than 2 m deep, are commonly used to store tailings and minimize environmental degradation. Studies have, however, shown that wind induced waves can erode and resuspend tailings in areas where the water cover is much shallower than 1 m, possibly leading to oxidation of sulphide minerals, acid generation, and release of heavy metals. The present work investigated erosion and resuspension of co-disposed, cohesive mill tailings and lime neutralization sludge in a tailings pond located at the Heath Steele mine site, near Miramichi, New Brunswick, Canada. From measured wind data and published equations, suspended sediment concentrations were modeled for various water cover depths and compared to measured total suspended solids (TSS) values and the federal effluent discharge guideline of 25 mg L^–1. The computed suspended sediment concentrations agreed with those measured at the effluent discharge point. The results show that winds blowing in the direction of the major axis of the pond contributed most to resuspension and elevated TSS. Key words: cohesive mine tailings and sludge, critical shear stress, wind-induced resuspension, effluent water quality.