Waste from mining activities has a negative impact on the environment when not handled properly. For her PhD studies, Ninni Jeremiassen investigated what happens to the waste rock at the former cryolite mine at Ivittuut, South Greenland. She collected rocks at Ivittuut and performed laboratory experiments that mimic different climatic conditions. The rocks were exposed to freshwater and seawater to determine how much and at what rate Pb, Zn and F are released from the waste rock during the weathering process. Through detailed mineralogical observations and geochemical analysis, Ninni Jeremiassen was able to show that the element release from various minerals is very different in terms of absolute mass as well as the temporal behavior. A key finding is the identification of a series of Pb-bearing secondary minerals that formed on galena crystal surface, which could have a positive impact (i.e. decrease) on the release of Pb. The results of the study give a better understanding on the geochemical effects of mineral weathering at Arctic conditions, which has implications for the handling of mining waste.

The PhD study was completed at Department of Geoscience, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Wednesday, 4^th of February 2026, 13:00 (Danish time) 10:00 (Greenlandic time)
Place: Building Ilimmarfik, auditorium, Grønlands Universitet, Manutooq 1, 3905 Nuussuaq, Grønland
Title of PhD thesis: Long-term leaching dynamics of lead, zinc, and fluorine from mine waste at the Ivittuut mine, South Greenland
Contact information: Ninni Jeremiassen e-mail: nije@geo.au.dk, tel.: +299 361241
Members of the assessment committee:
Associate Professor Mattias Bäckström, Örebro University, School of Science and Technology, Sweden
Senior Researcher Dr. Nynke Keulen, Geological Survey of Denmark and Greenland, Denmark
Professor Stéphane Bodin (chair), Department of Geoscience, Aarhus University, Denmark
Main supervisor: Associate Professor Vivi Kathrine Pedersen, Department of Geoscience, Aarhus University, Denmark
Co-supervisors:
Senior Researcher Dr. Violeta Hansen, Department of Medical Radiation Sciences, University of Gothenburg, Sweden
Professor Thomas Ulrich, Institute of Geotechnology and Mineral Resources, Department of Geosciences, Clausthal University of Technology, Germany
Senior Researcher Dr. Yu Jia, Department of Environment and Mineral Resources, Greenland Institute for Natural Resources, Greenland
Professor Henrik Friis, Natural History Museum, University of Oslo, Norway
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C