Acidic microenvironments in waste rock characterized by neutral drainage: Bacteria-mineral interactions at sulfide surfaces
Date
2014-03-21
Authors
Dockrey, John W.
Lindsay, Matthew B. J.
Mayer, K. Ulrich
Beckie, Roger D.
Norlund, Kelsey L. I.
Warren, Lesley
Southam, Gordon
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
ORCID
Type
Article
Degree Level
Abstract
Microbial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD). Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn) were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III) (oxy)hydroxide and Fe(III) (oxy)hydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS). Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS) spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH)6–4.5(SO4)1–1.75], lepidocrocite [γ-FeO(OH)] and K-jarosite [KFe3(OH)6(SO4)2]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.
Description
© 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).
Keywords
mine tailings, neutral rock drainage, biooxidation, Fe- and S-oxidizing bacteria, synchrotron, EXAFS
Citation
Dockrey, J.W., Lindsay, M. B. J., Mayer, K. U., Beckie, R. D., Norlund, K. L. I., Warren, L. A., & Southam, G. (2014). Acidic microenvironments in waste rock characterized by neutral drainage: Bacteria–mineral interactions at sulfide surfaces. Minerals (Basel), 4(1), 170–190. https://doi.org/10.3390/min4010170
Degree
Department
Program
Advisor
Committee
Citation
Dockrey, J.W., Lindsay, M. B. J., Mayer, K. U., Beckie, R. D., Norlund, K. L. I., Warren, L. A., & Southam, G. (2014). Acidic microenvironments in waste rock characterized by neutral drainage: Bacteria–mineral interactions at sulfide surfaces. Minerals (Basel), 4(1), 170–190. https://doi.org/10.3390/min4010170
Part Of
item.page.relation.ispartofseries
DOI
10.3390/min4010170