Biopolymer stabilization of mine tailings for dust control

Mine tailings, or mill tailings (MTs), are highly susceptible to wind erosion (dust) and have brought about different environmental and safety concerns. Many efforts have been attempted to stabilize MTs for dust control, but all have drawbacks. The current study investigates the feasibility of using two natural and renewable biopolymers, xanthan gum and guar gum, to stabilize MTs for dust control. Moisture retention and wind tunnel tests were performed to evaluate, respectively, the enhancement of water retention capacity and the improvement of resistance to wind dispersal after MTs were treated with biopolymer solutions of different concentrations. Because the resistance to the formation of dust is closely related to how easy the particles can be detached from the surface, a flat-ended cylindrical penetrometer was manufactured and used to evaluate the surface strength (maximum penetration force) of dry MT specimens treated with biopolymer solutions of different concentrations. Scanning electron microscopy imaging was also performed to investigate the evolvement of the microstructure of MTs after biopolymer treatment. The results indicate that both xanthan gum and guar gum are effective in enhancing the moisture retention capacity, improving the dust resistance, and increasing the surface strength of MTs beyond that of water wetting. This is mainly because the biopolymers form coatings on MT particles and create bonding between them. The results also demonstrate that the flat-ended cylindrical penetrometer is a promising technique for characterizing the dust resistance of MTs.