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发挥着重要作用。然而，在移走这些有价值的商品的同时，往往会产生大量的垃圾。如果管理不当，这些废物有可能对环境造成不利影响。当废物中含有硫化铁矿物时，需要特别注意。大气中氧气对硫化物的氧化往往会导致大气降水的酸化；这种现象称为酸性矿山排水(AMD)。在这些情况下，必须在矿场采取行动，防止AMD对环境造成影响。有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，但仍有许多工作需要在技术和经济上提高其性能。拟议的研究计划旨在为尾矿储存设施开发有效和经济的回收策略。将研究两个不同的项目：1)将粘土材料集成到工程覆盖物中，2)改进用于评估工程覆盖物性能的方法。在项目1中，将使用不同的技术对在活跃矿场附近采样的粘土材料进行表征。将进行室内试验，包括水力渗透性、冻融效应、孔径分布等评价。然后，将进行数值模拟，目的是评估盖子阻止水和氧气到达下面活性尾矿的能力。此外，现场仪表化的实验单元将被用来测试使用粘土材料的不同盖子配置。在项目2中，将利用实验柱测试在不同条件下对体积含水率测量设备进行测试，以评估硫含量、间隙矿化和温度对测量精度的影响。此外，在野外矿场，将使用测量的参数来评估水覆盖平衡的组成部分：蒸散(使用涡旋相关法)、储水量、径流、降水和入渗量。最后，将对结果进行详细分析，将使用水量平衡的各种分量间接估计的蒸散参数与用涡流协方差系统测得的蒸散参数进行比较。这些学生将接受培训，并将获得处理与非饱和水运动有关的复杂问题以及盖子设计和性能评估的技能。这些HQP将装备精良，能够设计出符合行业、政府和社区要求的有效覆盖件。

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.