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物，以控制对环境的水、气体和/或污染物负荷，同时监测这些覆盖物的性能。这项拟议的研究重点是开发与这些复垦土壤覆盖相关的新型监测和覆盖设计工具。土壤复盖监测的最具挑战性的一个因素是建立一个水量平衡，该平衡记录已关闭矿山整个地貌的土壤复盖的水文表现。这种监测传统上是使用土壤监测站或径流堰等本地化监测系统进行的。然而，本地化的测量结果很难跨大片填海地区进行整合。这在油砂开采中是一个特别大的挑战，一个矿场的复垦面积可能超过100平方公里。这项研究将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通过检测地下地质地层中对这些载荷的响应而发生的孔隙水压力的微小变化来测量地表载荷的变化(如土壤剖面中的水的重量)。第二个项目将研究为北部矿场设计季节性冻结毛细分流(SFCBD)覆盖层的可行性；在这里，细粒土壤不足以形成低渗透覆盖层，但由于气候寒冷，可以开发出冻结的、接近饱和的土层。这些覆盖物可以由分层的粗土壤(即沙/砾石)建造，以加强新鲜的融雪水从下层矿山废物向邻近的集水结构的横向分流。这种新颖的设计方法将一种已知的盖层设计方法(毛细破裂层)与独特的北方气候条件相结合，为加拿大北部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.