Environmental Impact of mine waste interactions with permafrost

这项研究计划将研究加拿大北极地区存在永久冻土的地区水合硫酸盐矿物和水合碳酸盐矿物的相关系、反应机理、化学变化和观察到的自然组合。与过去相比，矿藏更容易通过海路到达。如果我们要最大限度地减少对当地生态系统的影响，就需要了解开采这些矿藏的影响，以及在永久冻土地区产生的废物。在经历冻融循环或封闭在永久冻土中的矿山废物中发生的反应没有得到很好的研究。这些反应将通过实验室实验和对涉及这些非常活跃的矿物的稳定性和反应机理的现场观察相结合的方式进行研究。实地研究将通过研究1)天然铁帽矿床，2)受到采矿勘探但未开发的矿床，以及3)在北极地区产生的矿山废物，来调查永久冻土中或附近的反应。研究未受干扰的天然矿体提供了一个长期的实验，因为这些缓慢的低温反应自上一次冰川消退以来一直在进行。实地调查将由研究生进行，本科生支持，并将使用一些复杂的便携式仪器。在实验室里，学生们将在受控条件下重复观察到的自然反应。水合碳酸盐矿物也出现在多年冻土地区，最近我们在因努维克以西永久冻土的岩石裂缝中观察到了这些矿物。含水碳酸盐在永冻土表面附近形成，参与了二氧化碳从大气中的封存。火星表面被认为含有硫酸盐。美国宇航局的凤凰号着陆器在地表下发现了永久冻土，这项申请中提出的工作与这种情况下的矿物反应直接相关。火星上的大气富含二氧化碳，当与地下冰结合在一起时，为水合碳酸盐在火星上存在创造了意想不到的机会。

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.