Mine Waste Stabilization via Enzyme Induced Carbonate Precipitation: Field Deployment Study

Enzyme-Induced Carbonate Precipitation (EICP) was implemented at the field scale at a metal-impacted abandoned mine site to evaluate its feasibility for the surficial stabilization of mine wastes and tailings through biocementation. The study, conducted at the Cash Mine site in Arizona, aimed to reduce water-induced erosion of contaminated materials and prevent their transport into a tributary of the Upper Hassayampa River. Laboratory testing first confirmed the effectiveness of EICP formulations under site-specific geochemical conditions, followed by large-scale field deployment and post-treatment monitoring. The results demonstrate that EICP successfully produced carbonate crusts that increased surface strength and markedly reduced erosion at the field scale. However, the findings also revealed important limitations, including enzyme inhibition by high concentrations of some metals and enhanced leaching of certain metals into runoff and infiltrating water. This research provides one of the first comprehensive field demonstrations of EICP for mine-waste stabilization, offering new insights into its scalability, geochemical interactions, and practical considerations for sustainable mine-site remediation.