| Abstract
| - Effective treatment techniques for eliminating iron-oxidizing (IOB) and sulfur-oxidizing bacteria (SOB) arerequired for the comparison of abiotic and microbial sulfideoxidation rates and mechanisms in mine tailings. Thisstudy evaluates the effect of autoclaving, repeated heating,ethanol treatment, antibiotic treatment, γ-radiation, andwashing with deionized water on tailings characteristics andconcentrations of IOB and SOB. Most probable numberenumeration indicates that IOB and SOB were present atvery low concentrations or below detection limitsfollowing treatment with all methods except rinsing andantibiotics treatment, where higher concentrations of IOBand SOB were present. The physical, chemical, andmineralogical characterization of the tailings indicated nochanges in bulk mineralogy or bulk chemical compositionas a result of treatment. However, an increase in oxidizedsulfur species at the tailings surface, as determined byX-ray photoelectron spectroscopy, was observed for theheating, autoclaving, and antibiotics treatments. Batchweathering experiments, used to evaluate the effect oftreatment on element release rates, indicated that the finalelement release rates (after >30 d) were similar betweentreated and untreated control samples. On the basis ofthe results of this study, experiments over relatively longperiods (>30 d) are to be recommended for the establishmentof microbial and abiotic weathering rates in mill tailingssamples. For the determination of abiotic reaction rates,treatment by γ-radiation is suggested to be the mostappropriate method for sulfide-rich tailings.
|
