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

采矿完成后，矿场最终关闭的一个要素是建造复垦土壤覆盖层，以控制水、气体和/或污染物对环境的负荷，同时沿着监测这些覆盖层的性能。这项拟议的研究重点是开发新的监测和覆盖设计工具与这些填海土壤覆盖。土壤覆盖监测中最具挑战性的一个要素是水平衡的发展，以捕捉关闭矿山整个景观中土壤覆盖的水文性能。传统上，这种监测是使用本地监测系统进行的，如土壤监测站或径流堰。然而，局部测量难以在大面积填海区域进行整合。这在油砂开采中是一个特别的挑战，其中一个矿山的复垦面积可能超过100平方公里。这项研究将调查使用地质称重蒸渗仪（GWL）来监测关键的水文事件，如融雪径流，季节性蒸发，或与高强度夏季暴雨相关的径流。GWL通过检测响应于这些负载而发生的底层地质构造内的孔隙水压力的微小变化来测量表面负载（例如土壤剖面内保持的水的重量）的变化。第二个项目将调查为北方矿场设计季节性冻结毛细破裂导流（SFCBD）覆盖层的可行性;在这里，细粒土不足以形成低渗透覆盖层，但由于气候寒冷，可以形成冻结的近饱和土壤区。这些覆盖物可以由分层的粗土（即，砂/砾石），以增强新鲜雪融水从下面的矿山废物侧向转移到邻近的集水结构中。这种新颖的设计方法结合了已知的盖层设计方法（毛细管破裂层）与独特的北方气候条件，并为加拿大北方矿山的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.