Laboratory studies investigating chemical flux across tailings-cap water zones, simulating an End Pit Lake in the Athabasca oil sands region

在阿萨巴斯卡地区扩大油砂业务带来的经济机会是巨大的，但沥青开采过程的副产品也是如此。在景观修复方面具有特别重要的环境意义的是尾矿管理，更具体地说，是将关闭的矿坑用作尾矿库盆地的可能性。为了让这些所谓的尾矿湖(EPL)成为可接受的处置替代方案，尾矿必须覆盖一个淡水层，随着时间的推移，这个淡水层会发展成一个自我维持的生态系统。事实上，生态系统的成熟预计将与尾矿脱水同时发生，从而使EPLs成为北方针叶林的自然组成部分。 了解控制尾矿中污染物分配的生物地质化学过程和确定污染物到盖水区的传输路径是有用的。调节污染物的释放和传输是本多学科提案的总体目标。将通过考虑两种不同类型的实验室实验来实现研究目标：(I)在高温下进行的大体积动力学测试，以加速在现场缓慢演化的过程，以及(Ii)将更具体地探索化学分配的基本方面的小体积测试。在前一种情况下，我们的分析将包括关键微生物的测序以及粘土矿物、表达的孔隙水和盖水的化学特征。在后一种情况下，将重点关注营养限制、碎屑和盖水稀释效应。我们还建议单独调查这些因素(风应力等)。这导致了流体细粒尾矿和盖水层之间的混合。在整个过程中，结果将与我们的行业合作伙伴和附属研究小组进行沟通，以最大限度地发挥我们的研究结果和建议的影响。

The economic opportunities associated with expanded oil sands operations in the Athabasca region are substantial, but so too are the by-products of the bitumen extraction process. Of particular environmental importance in the context of landscape remediation is tailings management, more specifically the possibility of using closed mine pits as tailings repository basins. In order for these so-called end-pit lakes (EPLs) to represent an acceptable disposal alternative, tailings must be capped with a fresh water layer that, over time, develops into a self-sustaining ecosystem. Indeed ecosystem maturation is expected to occur simultaneously with tailings dewatering so that EPLs become a natural component of the boreal forest. It is useful to understand biogeochemical processes governing partitioning of contaminants in tailings and identify contaminant transport pathways to cap water. Modulating contaminant release and transport is the overall objective of the present multidisciplinary proposal. Research objectives will be met by considering two different types of laboratory experiments: (i) large volume kinetic tests conducted at elevated temperatures to accelerate processes that evolve slowly in-situ, and, (ii) small volume tests that will more specifically probe the fundamental aspects of chemical partitioning. In the former case, our analysis will include a sequencing of key microbes and a chemical characterization of clay minerals, expressed porewater and cap water. In the latter case, attention will be focused on nutrient limitation, detritus and cap water dilution effects. We also propose to separately investigate those factors (wind stress, etc.) that lead to mixing between the fluid fine tailings and cap water layers. Throughout, results will be communicated with our industrial partner and with affiliated research groups for purposes of maximizing the impact of our findings and recommendations.