Professional Engineers Of North Carolina

SUM 2014

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9 Summer 2014 the Professional Engineer earthwork fexibility and FAA approval — at their technical basis. Leachability can be evaluated by TCLP and multiple other methods (U.S. EPA Methods 1313, 1314, 1315, and 1316; ASTM C1308, etc.) to ascertain the extent to which contaminants of concern could be mobile. Test results can then be used to inform a proposed design that prevents such mobility. For example, the ash contractor proposed encapsulating the ash in a HDPE textured 60-mil geomembrane as well as a geosynthetic clay liner, complete with drainage layer and leachate collection system much as exists for landflls. Leaching is not a concern with such a design. As ASTM E2277 notes, "Many coal combustion products (includes CFA) materials have been efectively used for benefcial reuse in engineered structural flls and have been shown to have little or no potential for releasing constituents to the environment when placed and compacted at the proper moisture content and with suitable engineering controls." In terms of strength and stability, CFA flls can be evaluated according to established geotechnical engineering practices applied to natural soils. Tis may involve a laboratory testing program and numerical The Dan River runs gray soon after the February ash spill. App Voices

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