Environmental Impact of mine waste interactions with permafrost

点击翻译按钮获取中文摘要

This research program will investigate the phase relationships, reaction mechanisms, chemical variations, and observed natural associations of hydrated sulfate minerals and hydrated carbonate minerals as they occur in regions of the Canadian Arctic where permafrost exists. Mineral deposits are more accessible by sea than in the past. The impact of mining these deposits, and the waste that is generated in permafrost regions needs to be understood if we are to minimize the effects on the local ecosystem. The reactions that occur within mine waste that undergo freeze-thaw cycles or that are enclosed in permafrost are not well studied. These reactions will be investigated through a combination of laboratory experiments on, and field observations of, the stability and reaction mechanisms that involve these very reactive minerals. Field studies will investigate the reactions in or near permafrost by studying 1) natural gossan deposits, 2) ore deposits disturbed by mining exploration but not exploited and 3) mine waste that has been created in the Arctic region. Studying natural, undisturbed ore bodies provides a long-term experiment as these sluggish low- temperature reactions have been progressing since the retreat of the last glaciation. The fieldwork will be conducted by graduate students and supported by undergraduate students and will use a number of sophisticated portable instruments. In the laboratory, students will duplicate observed natural reactions under controlled conditions. Hydrated carbonate minerals also occur in permafrost regions and recently we have observed these minerals in fractures in rocks in permafrost west of Inuvik. The hydrous carbonates form near the permafrost surface and participate in the sequestration of CO2 from the atmosphere. The surface of Mars is thought to contain sulfates. The NASA lander Phoenix discovered permafrost just below the surface and the work proposed in this application has direct relevance to mineral reactions in such a situation. The atmosphere on Mars is rich in CO2 and when combined with subsurface ice creates the unexpected opportunity for hydrated carbonates to exist on Mars.************