TemaNord 2017:525 Water Conscious Mining (WASCIOUS) Conscious Water 2017:525 TemaNord Nordic Council of Ministers Ved Stranden 18 DK-1061 Copenhagen K www.norden.org Water Conscious Mining (WASCIOUS) Water Conscious Mining (WASCIOUS) The main objective of the NordMin WASCIOUS project was to develop a technology concept for water conscious mining, where innovative water and tailings treatment technologies provide good-quality water for recycling and discharge and enable safe disposal or utilization of tailings. The work included a survey on current practices and requirements in Nordic mines and laboratory and pilot scale development of several technologies. Computational simulations of water treatment and recycling practices were performed for a feasibility study of some technology alternatives and technologies for dewatering of tailings were evaluated. As an important outcome of the project, a future Nordic research platform was established related to environmental issues in mining for the Nordic region, enabling exchange of ideas and collaboration in future project calls, and facilitating ideas for future projects. 1 Water Conscious Mining (WASCIOUS) Margareta Wahlström, Tommi Kaartinen, Jarno Mäkinen and Henna Punkkinen, Antti Häkkinen, Maria Mamelkina and Ritva Tuunila, Pertti Lamberg and Maria Sinche Gonzales, Marius Sandru and Heidi Johnsen, Jens-Petter Andreassen, Vigdís Harðardóttir and Hjalti Franzson, Christina Sund and Kaj Jansson TemaNord 2017:525 Water Conscious Mining (WASCIOUS) Margareta Wahlström, Tommi Kaartinen, Jarno Mäkinen and Henna Punkkinen, Antti Häkkinen, Maria Mam- elkina and Ritva Tuunila, Pertti Lamberg and Maria Sinche Gonzales, Marius Sandru and Heidi Johnsen, Jens- Petter Andreassen, Vigdís Harðardóttir and Hjalti Franzson, Christina Sund and Kaj Jansson ISBN 978-92-893-4961-1 (PRINT) ISBN 978-92-893-4962-8 (PDF) ISBN 978-92-893-4963-5 (EPUB) http://dx.doi.org/10.6027/TN2017-525 TemaNord 2017:525 ISSN 0908-6692 Standard: PDF/UA-1 ISO 14289-1 © Nordic Council of Ministers 2017 Cover photo: Päivi Kauppila Print: Rosendahls Printed in Denmark This document has been published with financial support from NordMin – A Nordic Network of Expertise for a Sustainable Mining and Mineral Industry, funded by the Nordic Council of Ministers. Although the Nordic Council of Ministers funded this publication, the contents do not necessarily reflect its views, policies or recommendations. Nordic co-operation Nordic co-operation is one of the world’s most extensive forms of regional collaboration, involving Denmark, Finland, Iceland, Norway, Sweden, the Faroe Islands, Greenland, and Åland. Nordic co-operation has firm traditions in politics, the economy, and culture. It plays an important role in European and international collaboration, and aims at creating a strong Nordic community in a strong Europe. Nordic co-operation seeks to safeguard Nordic and regional interests and principles in the global community. Shared Nordic values help the region solidify its position as one of the world’s most innovative and competitive. Contents Preface ..................................................................................................................................... 5 Terms and definitions .......................................................................................................... 7 Abbreviations ..................................................................................................................... 8 Summary ................................................................................................................................. 9 1. Introduction ...................................................................................................................... 13 1.1 Water conscious mine – concept ............................................................................. 13 1.2 Objectives ............................................................................................................... 15 1.3 Nordic partners and Nordic excellence network ...................................................... 16 1.4 Dissemination of project results ............................................................................. 19 1.5 References ............................................................................................................. 19 2. Current solutions for mine water management .................................................................. 21 2.1 Objective of the survey ........................................................................................... 21 2.2 Operating metal mines in Nordic countries.............................................................. 21 2.3 Summary of waste water qualities and quantities at metal mines ........................... 33 2.4 Summary of current waste water treatment practices at metal mines .................... 36 2.5 Possible future mining activities ..............................................................................38 2.6 Summary ................................................................................................................41 2.7 State-of-the-art on water treatment .......................................................................43 3. Technological developments ............................................................................................ 61 3.1 Research fields covered .......................................................................................... 61 3.2 Biosorption studies ................................................................................................ 63 3.3 Ettringite precipitation process for sulphate removal from mine water ................... 66 3.4 Ettringite precipitation process for sulphate removal from mine water with aluminium recovery, LoSO4™ ................................................................................. 73 3.5 Evaluation of Eutectic Freeze Crystallization for water treatment ............................ 78 3.6 Electrochemical treatment of mine waters ..............................................................83 3.7 Membrane processes in water treatment ............................................................... 90 3.8 Precipitation processes ........................................................................................... 97 3.9 Biological processes for nitrogen removal from mine water ................................... 107 3.10 Summary of technology developments ................................................................. 114 4. Aspects of water conscious mine concept ....................................................................... 117 4.1 Water foot print .................................................................................................... 117 4.2 Water recycling ..................................................................................................... 117 4.3 Removal of water from tailings ............................................................................. 118 4.4 Active and passive water treatment technologies at disposal site ............................... 120 4.5 References ............................................................................................................ 121 5. Case studies: Simulation and modelling of flows at mines ................................................ 123 5.1 Modelling and simulations of water balance for mining operation ......................... 123 5.2 Case studies with Capex/Opex estimate ................................................................ 134 5.3 Tailings management – Minimum impact concentrator – summary of a conceptual study ................................................................................................... 139 6. Conclusions and recommendations ................................................................................. 143 6.1 Technological development .................................................................................. 143 6.2 Water conscious mining concept studied in this project ......................................... 144 Sammanfattning ................................................................................................................... 147 Appendices ........................................................................................................................... 149 Appendix 1: The recipe for the preparation of synthetic mine waters ............................... 149 Appendix 2: Tool developed by Veolia for assessment of Water Impact Index .................. 151 Appendix 3: Simulation of water recycling: Additional information by LTU, Sweden ........ 154 Appendix 4: Tailings management – Minimum impact concentrator – a conceptual study ................................................................................................ 158 Preface This work was conducted as a part of the “Water conscious mining” (WASCIOUS) project, funded by NordMin – a Nordic Network of Expertise for a Sustainable Mining and Mineral Industry. The project was initiated in April 2014 and was finished in November 2016. The use of metals in modern society has been constantly increasing in recent years. Finland, Sweden and Norway have developed national mineral strategies, which especially emphasize the importance of continued exploration and exploitation of minerals by sustainable mining activities. It is important to secure sustainable metal production in the Nordic countries with a higher level of environmental awareness