Large scale mine cover monitoring and mine cover design for cold regions

采矿完成后，矿场最后关闭的一个要素是建造复垦土壤覆盖物，以控制水、气和/或污染物对环境的负荷，并监测这些覆盖物的性能。本研究的重点是开发与这些复垦土壤覆盖物相关的新型监测和覆盖物设计工具。土壤覆盖监测中最具挑战性的一个因素是水平衡的发展，该平衡可以捕获封闭矿山整个景观中土壤覆盖的水文性能。这种监测传统上是使用局部监测系统进行的，例如土壤监测站或径流堰。然而，局部测量很难在大面积的填海地区进行整合。这在油砂开采中是一个特别的挑战，因为一个矿山的填海面积可能超过100平方公里。本研究将调查地质称重溶渗仪（gwl）的使用，以监测关键的水文事件，如融雪径流、季节性蒸发或与夏季强暴雨相关的径流。gwl测量地表荷载的变化（如土壤剖面中水分的重量），方法是检测底层地质构造中孔隙水压力的微小变化，这些变化是对这些荷载的响应。第二个项目将调查在北部矿区设计季节性冻结毛细管破裂导流（SFCBD）覆盖物的可行性；在这里，细粒土壤不足以形成低入渗覆盖，但由于气候寒冷，可以形成冻结的、接近饱和的土壤区。这些覆盖层可以由层状的粗土（即砂/砾石）构成，以加强从下面的矿山废物中吸取的新鲜雪融水向邻近的集水结构的侧向转移。这种新颖的设计方法将已知的覆盖层设计方法（毛细管破碎层）与独特的北部气候条件相结合，为加拿大北部矿山的覆盖层设计提供了另一种潜在的选择。

Following the completion of mining, one element of the final closure of mine sites is the construction of reclamation soil covers to control water, gas, and/or contaminant loadings to the environment along with monitoring of the performance of these covers. This proposed research focuses on the development of novel monitoring and cover design tools associated with these reclamation soil covers. The single most challenging element of soil cover monitoring is the development of a water balance that captures the hydrological performance of the soil cover across the entire landscape of the closed mine. This monitoring has traditionally been done using localized monitoring systems such as soil monitoring stations or runoff weirs. However, the localized measurements are difficult to integrate across large reclaimed areas. This is a particular challenge in oilsands mining where the reclaimed areas for one mine might extend over 100s of square km. This research will investigate the use of geological weighing lysimeters (GWLs) to monitor key hydrological events, such as snowmelt runoff, seasonal evaporation, or runoff associated with high intensity summer rainstorms. GWLs measure changes in surface load (such as the weight of water held within the soil profile) by detecting small changes in pore-water pressure within underlying geological formations that occur in response to these loads. A second project will investigate the feasibility of designing a seasonally frozen capillary break diversion (SFCBD) cover for northern mine sites; here, insufficient fine-grained soils exist to create low infiltration covers but frozen, near saturated soils zones can be developed as a result of the cold climate. These covers can be constructed of layered coarse soil (i.e., sand/gravel) to enhance the lateral diversion of fresh snow melt water away from the underlying mine waste into adjacent water collection structures. This novel design approach combines a known cover design method (capillary break layers) with the unique northern climatic conditions and provides another potential option for cover design for mines in northern Canada.