Technosol Evaluation for Mine Site Reclamation in the Boreal Shield
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Technosol evaluation for mine site reclamation in the Boreal Shield by Renate Vanderhorst A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (MSc) in Biology Faculty of Graduate Studies Laurentian University Sudbury, Ontario, Canada © Renate Vanderhorst, 2018 THESIS DEFENCE COMMITTEE/COMITÉ DE SOUTENANCE DE THÈSE Laurentian Université/Université Laurentienne Faculty of Graduate Studies/Faculté des études supérieures Title of Thesis Titre de la thèse Technosol Evaluation for Mine Site Reclamation in the Boreal Shield Name of Candidate Nom du candidat Vanderhorst, Renate Degree Diplôme Master of Science Department/Program Date of Defence Département/Programme Biology Date de la soutenance January 12, 2018 APPROVED/APPROUVÉ Thesis Examiners/Examinateurs de thèse: Dr. Graeme Spiers (Co-Supervisor/Co-Directeur de thèse) Dr. Peter Beckett (Co-Supervisor/Co-Directeur de thèse) Dr. Nathan Basiliko (Committee member/Membre du comité) Mr. Shane Hayes (Committee member/Membre du comité) Approved for the Faculty of Graduate Studies Approuvé pour la Faculté des études supérieures Dr. David Lesbarrères Monsieur David Lesbarrères Dr. Les Lavkulich Dean, Faculty of Graduate Studies (External Examiner/Examinateur externe) Doyen, Faculté des études supérieures ACCESSIBILITY CLAUSE AND PERMISSION TO USE I, Renate Vanderhorst, 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. ii Abstract Technosols, soils substantially influenced by human activity, are often found on former mine sites. In some cases they develop as a result of natural processes on abandoned sites; in others, they are intentionally manufactured as part of the mine’s reclamation program. In this study Technosols with either 40% woody residuals and 60% mine rock or 80% woody residuals and 20% mine rock were constructed and placed over mine rock lysimeters in either 30 cm or 60 cm layers to evaluate their potential for use in the reclamation of a gold mine in the Canadian boreal forest. The Technosol plots were constructed in summer 2012 and have been continuously monitored for water chemistry, soil microclimate, and vegetation health. In 2016 soil pits were excavated to examine the physical, chemical, and microbial development of Technosol profiles. The high organic Technosols had higher concentrations of bioavailable nutrients, reduced availability of Mo and Cd, less extreme soil temperatures, increased soil moisture, and reduced soil pH compared to the low organic. In all Technosol plot water samples pH was between 7 – 8, high levels of DOC were measured, and no elements exceeded site compliance limits specified by the Ontario government. Little profile development was observed in the Technosols, but there were differences between comparison field and forest soils in terms of chemistry and microbial functional diversity. Green alder (Alnus viridis subsp. crispa) grew well on the Technosol plots, but bearberry (Arctostaphylos uva-ursi) struggled and after two years almost complete mortality was seen. This is likely due to a combination of factors including high soil pH, low moisture, and low nutrient availability in the Technosols. Overall the high organic Technosol appears more suitable for reclamation, and green alders are a good choice for initial planting. Keywords: Technosol; mine reclamation; pedogenesis; revegetation; water chemistry iii Acknowledgements I would like to thank my supervisors, Dr. Graeme Spiers and Dr. Peter Beckett, for all the support and guidance they provided me. Their continued enthusiasm throughout reminded me that even though it was frustrating at times, the project still was an interesting one. I would also like to thank the members of my committee, Dr. Nathan Basiliko and Shane Hayes, for their insights and the helpful and thought-provoking questions they asked during the past two years which helped me keep this thesis focused. Thanks also to Autumn Watkinson, who completed the first two years of this project as her MSc and was kind enough to provide me with data, photos, and reports which were invaluable to me. I received much appreciated sampling and lab help from lab staff, graduate students, and summer students, including Troy Maki at ELRFS, Alan Lock, Emily Smenderovac, Cyndy Desjardins, Jasmine Serré, Jaime Caplette, and Cassieanna Krane. Financial support from Barrick-Hemlo, the Canadian Land Reclamation Association, and the Laurentian University NSERC Graduate Student Incentive Fund made this project possible. I would also like to thank the Vale Living with Lakes Centre and everyone who works there for providing such a friendly and helpful work environment, and friends and family for their encouragement throughout. iv Table of contents Abstract .......................................................................................................................................... iii Acknowledgements ........................................................................................................................ iv Table of contents ............................................................................................................................. v List of tables ................................................................................................................................. viii List of figures .................................................................................................................................. x List of abbreviations ................................................................................................................... xvii Chapter 1. Technosols and reclamation .......................................................................................... 1 Introduction ................................................................................................................................. 1 Mining and land reclamation .................................................................................................. 1 Technosols .............................................................................................................................. 2 Technosol use in mine reclamation ......................................................................................... 6 Using Technosols to reclaim a gold mine ................................................................................. 10 Rationale ............................................................................................................................... 10 Study site ............................................................................................................................... 10 Study design .......................................................................................................................... 12 Previous findings .................................................................................................................. 14 Objectives of this study ......................................................................................................... 15 Chapter 2. Chemistry of a mine rock Technosol in the Boreal Shield ......................................... 16 Introduction ............................................................................................................................... 16 Methods..................................................................................................................................... 17 Study area.............................................................................................................................. 17 Site design ............................................................................................................................. 18 Soil sampling and analysis .................................................................................................... 19 Water sampling and analysis ................................................................................................ 21 Results ....................................................................................................................................... 22 Soil chemistry ....................................................................................................................... 22 Water chemistry ...................................................................................................................