Integration of clayey materials in the engineered covers and improvement of their performance evaluation techniques

矿产资源的开采在加拿大经济中起着重要作用。然而，在清除这些有价值的商品时，往往会产生大量的废物。如果管理不当，这些废物有可能对环境产生不利影响。当废物中含有硫化铁矿物时，需要特别注意。大气氧对硫化物的氧化往往导致大气水体的酸化；这种现象被称为酸性矿井水（AMD）。在这些情况下，必须在矿区采取行动，防止AMD对环境造成的影响。不同的管理选择和康复策略可用于抑制AMD的产生。尽管这些技术得到了发展，但在技术和经济上仍需改进其性能。拟议的研究计划旨在为尾矿储存设施制定有效和经济的回收战略。两个不同的项目将被研究：1)粘土材料在工程盖的集成，2)改进用于评估工程盖性能的方法。在项目1中，在活跃矿区附近取样的粘土材料将使用不同的技术进行表征。将进行实验室测试，包括评估水力渗透性、冻融效应、孔隙大小分布等。然后，将进行数值模拟，目的是评估覆盖层阻止水和氧气到达下面活性尾矿的能力。此外，现场仪器实验单元将用于测试使用粘土材料的不同覆盖结构。研究结果可用于评价覆盖层的性能，并验证包含粘土层的覆盖层是否可用于矿区复垦。在项目2中，将对体积含水量测量设备进行不同条件下的实验柱测试，目的是评估硫含量、间隙矿化和温度对测量精度的影响。此外，在野外矿场，将使用测量参数评价水覆盖预算的组成部分：蒸发蒸腾（使用涡动相关法）、水储存、径流、降水和渗透。最后，将对结果进行详细分析，以比较使用水平衡的各个组成部分间接评估的蒸散发参数与涡动相关系统测量的蒸散发参数。这项工作将由PHQ学生完成。这些学生将接受培训，并将获得管理与非饱和水运动有关的复杂问题的技能，以及覆盖物设计和性能评估。这些HQP将装备精良，能够设计出满足工业、政府和社区要求的有效掩体。

The extraction of mineral resources plays an important role in the Canadian economy. However, while removing these valuable commodities, large volumes of waste are often generated. These wastes have the potential to adversely impact the environment if not properly managed. Special attention is required when the wastes contain iron sulfide minerals. The oxidation of sulfides by atmospheric oxygen tends to lead to the acidification of meteoric waters; this phenomenon is known as acid mine drainage (AMD). In these situations, actions must be taken at the mine site to prevent environmental impacts caused by AMD. Different management options and rehabilitation strategies are available to inhibit AMD production. Despite the development of these techniques, there is still work that must be performed to improve their performance both technically and economically.The proposed research program seeks to develop effective and economical reclamation strategies for tailings storage facilities. Two distinct projects will be investigated: 1) integration of clayey materials in engineered covers, and 2) improving methods used to evaluate engineered covers' performances.In Project 1, clayey materials sampled near active mine sites will be characterized using different technics. Lab tests will be performed including evaluation of hydraulic permeability, freeze Thaw effect, pore-size distributionetc. Then, numerical modelling will be performed with the objectives to assess the ability of covers to block water and oxygen from reaching the underlying reactive tailings. Also, field instrumented experimental cells will be used to test different cover configurations using clayey materials. The results allow for an evaluation of cover performance and verification of whether or not a cover including a clay layer could be used in mine site reclamation.In the project 2, equipments for volumetric water content measurement will be tested under different conditions using experimental column tests with the objective to evaluate the impact of sulfur contents, interstitial mineralization and temperature on the measurements' accuracies. Also, at field mine site, components of water cover budget will be evaluated using measured parameters: evapo-transpiration (using eddy covariance method), water storage, runoff, precipitation and infiltration. Finally, a detailed analysis of results will be performed to compare evapotranspiration parameter indirectly assessed using the various components of the water balance to that measured with the eddy covariance system.The work will be performed by PHQ students. These students will be trained and will acquire skills in managing complex problems related to unsaturated water movement as well as cover design and performance evaluation. These HQP will be well equipped to design effective covers that meet industrial, governmental, and community requirements.