Stabilization of iron mine tailings through microbially induced calcite precipitation

Mine tailings are deposited into large-scale impoundments. Seasonal temperature fluctuations destabilize particles on the impoundment surface. Wind-induced shear stresses on the destabilized particles can in turn result in suspension of micron-sized particles into the atmosphere, creating dust storms that pose hazards to humans and the environment. Thus, efficient and sustainable methods of dust abatement are needed. One novel method for controlling dust emissions is biomodification. For example, Sporosarcina pasteurii can promote biocalcification in soil via ureolysis. However, application of this method to fined grained materials, such as mine tailings, is challenging. The goal of this work was to perform a proof-of-concept demonstration of biocalcification applied to mine tailings, and examine the associated strength increase at the soil surface. Laboratory experiments coupled with multiple analytical methods were used to confirm the formation of the surface crust, and its impact on strength. Crust formation was demonstrated with S. pasteurii and native microorganisms.