Institute: West Virginia
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $19,633 Total Non-Federal Funds: $40,212
Principal Investigators: Leslie Hopkinson
Abstract: The purpose of this project is to examine the erosion and sedimentation controls on mine impoundments that have progressed from operation towards closure and abandonment. The closure rates of idled coal refuse impoundments are increasing and there is an opportunity to evaluate erosion control measures and monitor their performance in advance of complete mine site abandonment. Surface contours and vegetative surface cover at coal impoundment structures are engineered to limit the erosive forces that are developed during precipitation events to control sediment transport and to lower landslide hazard potential; however, monitoring is needed to understand the erosion potential. Coal refuse impoundments are constructed as earthen embankment dams which primarily concentrate coal refuse and secondarily retain process water containing coarse and fine coal refuse fractions. Coal refuse impoundments in the Appalachian region are primarily constructed as cross-valley structures and are situated in upstream valleys. There are more than 600 active coal-related impoundments in the United States; with West Virginia having more than 100 of these impoundments (MSHA, 2013). Inactive or abandoned impoundments are not included in this count. As a result of reduced coal production, the inactive permitted impoundments are being closed and reclaimed following WV DEP guidelines. Impoundment closure requires that the dam and reservoir be constructed to provide positive precipitation drainage. Coal refuse is a non-combustible waste material produced during coal mining and material handling processes. The refuse is characterized as having rock fragments of shale, mudstone, and varying amounts of residual coal. The refuse may contain combustible coal depending on separation efficiency, placement location, and the age and efficiency of the material handling methods. Impoundment construction technique and refuse deposition varies and can include conditions of complete material segregation to a blending of the refuse at placement. The absence of cohesion increases the erodibility characteristics of the refuse enabling hydraulic mobility during concentrated precipitation runoff which perpetuates surface erosion and fine sediment runoff. The research activities proposed are to perform field studies to inspect and monitor one or two abandoned coal refuse impoundments, then investigate the erosion conditions and establish a base-line to further monitor targeted field locations and parameters after selected high intensity precipitation events occurring over the course of the project period. We will obtain field samples and test refuse properties, identify erosive forces and rates, and perform computational computer modeling enabling us to predict erosion, soil loss, and runoff potential into nearby surface water tributaries. Outcomes of this research are expected to identify erosion and sediment transport data which could assist with post mine site closure operations. Research findings will be shared with public community partners and governmental regulatory agencies at the state and federal level. We will train one graduate student, publish the results of this study in peer reviewed journals, and present the findings at conferences.