AN INVESTIGATION INTO BIOLEACHING OF URANIUM AND RARE EARTH ELEMENTS FROM QUARTZ-PEBBLE CONGLOMERATE ORES FROM ELLIOT LAKE, ONTARIO By Aimee Lynn Williamson A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (PhD) in Material Sciences The School of Graduate Studies Laurentian University Sudbury, Ontario, Canada © Aimee Lynn Williamson, 2014 THESIS DEFENCE COMMITTEE/COMITÉ DE SOUTENANCE DE THÈSE Laurentian Université/Université Laurentienne School of Graduate Studies/École des études supérieures Title of Thesis Titre de la thèse AN INVESTIGATION INTO BIOLEACHING OF URANIUM AND RARE EARTH ELEMENTS FROM QUARTZ-PEBBLE CONGLOMERARE ORES FROM AT ELLIOT LAKE, ONTARIO Name of Candidate Nom du candidat Williamson, Aimee Lynn Degree Diplôme Doctor of Philosophy Department/Program Date of Defence Département/Programme Materials Science Date de la soutenance June 3, 2014 APPROVED/APPROUVÉ Thesis Examiners/Examinateurs de thèse: Dr. Graeme Spiers (Supervisor/Directeur de thèse) Dr. François Caron (Committee member/Membre du comité) Dr. Michael Schindler (Committee member/Membre du comité) Mr. Roger Payne (Committee member/Membre du comité) Approved for the School of Graduate Studies Mr. Randy Knapp Approuvé pour l’École des études supérieures (Committee member/Membre du comité) Dr. David Lesbarrères M. David Lesbarrères Dr. Thomas Kotzer Director, School of Graduate Studies (External Examiner/Examinateur externe) Directeur, École des études supérieures Dr. Douglas Boreham (Internal Examiner/Examinateur interne) ACCESSIBILITY CLAUSE AND PERMISSION TO USE I, Aimee Lynn Williamson, hereby grant to Laurentian University and/or its agents the non-exclusive license to archive and make accessible my thesis, dissertation, or project report in whole or in part in all forms of media, now or for the duration of my copyright ownership. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also reserve the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head of the Department in which my thesis work was done. It is understood that any copying or publication or use of this thesis or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that this copy is being made available in this form by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. Abstract Biogeochemical mineral dissolution, the microbial-assisted dissolution of minerals, is an effective method for economically promoting the release of metals of interest from ores and mine waste materials. As the low-grade ores of the Elliot Lake region may be suitable for development of a sustainable heap-leach method for the extraction of U and REEs from the low-grade host mineralization, this thesis is focused on the geochemical and biological process simulation monitoring of the biogeochemical release of elements to the leaching solutions. The response of the retired heap material to a variety of passive closure strategies is also addressed. A series of biogeochemical mineral dissolution experiments have provided a detailed understanding of the biogeochemical mineral dissolution process, with the investigation of passive approaches to prepare for decommissioning to determine suitability to the ore materials from the study site. The chemical analyses of effluents collected throughout the experimentation, coupled with mineralogical and geochemical analyses of the feed and residual mineral material has enabled an understanding of the chemical controls of the overall biogeochemical mineral dissolution process for Fe, U, and Th, together with the preferential leaching release patterns for REEs, to be obtained. A mechanism describing U retention in secondary coatings has been proposed, with a passive approach to closure using inhibition and encapsulation methods being demonstrated, along with a determination of the potential for ongoing radionuclide release from a simulated heap upon decommissioning. The laboratory research in this study has shown that biogeochemical mineral dissolution, followed by waste material encapsulation, can be successfully applied to heap-leach pads potentially, enabling the economic recovery of U, Th, and selected REEs to solution for subsequent metallurgical collection. The studies strongly support the concept of sustainable development for heap-leach operations in the Elliot Lake region. Keywords: Acid mine drainage, Acidithiobacillus ferrooxidans, biogeochemical mineral dissolution, bioleaching, passive approaches to prepare for decommissioning, Elliot Lake, encapsulation, extraction iii flasks, ferrous-sulphide minerals, geochemical dynamics, inhibition, leaching columns, mineralogical dynamics, radionuclide, radium, rare earth elements, uranium, thorium iv Co-Authorship Statement Recently published in the Journal of Environmental Radiochemistry, Chapter 9 is co-authored by Aimee Lynn Williamson, Francois Caron, and Graeme Spiers. Spiers contributed to the conception of the overall study, with Caron providing suggestions for leachate extraction and preparation for gamma measurements, calculating detector efficiency, and providing guidance on interpretation of gamma spectroscopic data. Williamson solely conducted all experiments and analysis, and conceived the interpretations and conclusions. The manuscript was prepared by Williamson, with editorial comment from Caron and Spiers. v Acknowledgments Completing this thesis has been the most challenging task I have attempted in my journeys and it would not be achievable without the assistance and support of countless individuals throughout the last four years, eight months, and twenty-four days. First and foremost, I would like to thank my thesis supervisor, Dr. Graeme Spiers, who has encouraged me every step of the way. He has taught me to trust my scientific judgment and to never give up when times get difficult or science gets tough. His lessons have allowed me to grow into a confident scientist, albeit stubborn at times as I continued to practice patience, which Dr. Spiers exemplifies so well. I would also like to thank my thesis committee members: Dr. Francois Caron, Dr. Michael Schindler, Mr. Roger Payne, and Mr. Randy Knapp. I am grateful that such a diverse group of professionals have guided me through this process. I have learned something unique from each of you. I have been grateful to have been supported by the folks at Pele Mountain Resources Inc. who entrusted me to find a solution for the company’s research questions. Communications with PMR president, Mr. Alan Shefsky, have always been positive and encouraging and his excitement for the project has provided never-ending motivation. Roger Payne, PMR Executive Vice President, has always brought positivity to the project and was truly one of the best resources that I had during my studies, although there has never been enough time to take full advantage of everything that Roger could teach me from all of his extraordinary experiences. Also, thank you to Fergus Kerr, who provided great insight and experience to the early phase of the project. The opportunity to work directly with a company on this project has allowed me to witness the true meaning of my work and its consequences. The body of experimental work could not have been completed without the assistance provide by the Geoscience Laboratories, the Elliot Lake Research Field Station, the Department of Chemistry at Laurentian University, and MIRARCO. Sample preparation and preliminary mineralogical studies were conducted at the Geoscience Laboratories, with special thanks to Sandra Clark and John Hechler for their continued guidance in this area. The great people at ELRFS have been available every step of the way, in vi particular Troy Maki, who has supported the development of analytical methods and carried out some sample analysis. A special thank you goes out to former-ELRFS staff member and fellow graduate student Kendra Driscoll for her support in the laboratory and for always being available for a coffee break to discuss our research results and life in general. I would also like to acknowledge the Chemistry Department at Laurentian University for providing countless supplies and small instruments required to complete special analysis and to Dr. Joy Gray-Munro for the use of her laboratory for an IR study. MIRARCO and the EMR research group have provided administrative support to the project as well as a personal workspace and facilities that any grad student could appreciate. I am very thankful for the friendships I developed working with the old CEM group at MIRARCO, established during fieldwork excursions and strengthened during conference outings and holiday parties. Special thanks to Dr. Jennifer Hargreaves for her ‘groovy’ guidance and to John Waddell, Michael Folcher, and Widjdan Malik for their assistance in the construction of my experimental set up. The support that I have received from friends and family has been so strong. Andrea and Josée, grad school would have been nowhere near as exciting