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Mr.Glen Mallory <br /> Coal Ash Disposal <br /> April 2,1999 <br /> Page 2 of 3 <br /> Since Varra Companies, already has an approved Backfill Permit from the Colorado Division of <br /> Minerals and Geology, the use of inert fill at both locations shown on the included maps is <br /> allowed (Backfill notices attached). Its is our understanding that Weld County has no permitting <br /> requirements for this use, and looks to CDH and DMG for its authority over such matters. <br /> Part of the problem of the Backfill Notice is the scarcity of suitable fill materials. If coal ash <br /> could be affirmed as `inert', under saturated conditions, its use, and attending benefits, could <br /> become immediately accessible to the region. We would like to work with you via this `Pilot <br /> program to determine by application the reliability of this use. <br /> Our initial evaluation indicates that coal ash exhibits natural soil like properties. Our evaluation <br /> is supported by information provided by Dragun, 1979, available published literature on coal ash <br /> disposal, analytical data provided by Public Service Company and batch leaching experiments <br /> performed at Colorado State University and at the University of North Dakota. Based on these <br /> data, we believe the possibility exists to reclaim alluvial gravel pits with coal ash without adverse <br /> impact to the environment. <br /> Analytical data provided by Public Service show that the concentrations of various elements are <br /> similar to those found in native soils. Leaching data (TCLP) substantiate that coal ash samples <br /> submitted by Public Service are not indicative of a characteristic hazardous waste. With the <br /> exception of pH, the TCLP leachate did not have constituents (including heavy metals) in excess <br /> of human health standards for drinking water. This indicates to us that the potential of trace metal <br /> migration in groundwater is minimal. <br /> In addition, hazardous organic constituents were not detected. Batch leaching experiments <br /> performed by CSU show that with the exception of calcium, trace metal ions, sulfate, chloride <br /> and bicarbonate were reduced to less than 10 percent of initial effluent concentrations after less <br /> than one pore volume of water had passed through the column. This is another strong indication <br /> that fly ash will not serve as a long term contaminant source. Synthetic Groundwater Leaching <br /> Procedure and Long Term Leaching experiments (agitated leaching experiments) performed at <br /> the University of North Dakota document that the elemental concentrations in leachate from coal <br /> ash were well below any RCRA standards and were below primary drinking water standards for <br /> most elements. We have provided analytical data as an attachment to this correspondence. <br /> Based upon the several environmental benefits, and as implied by the available data that supports <br /> the potential for the properties of coal ash to be inert, the Pilot study appears worthy of serious <br /> consideration. The pilot study designates a comparatively small area, substantially removed from <br /> the main tributary, yet large enough to test the disposal in a real world setting, under unlined <br /> saturated conditions. Once the determination is made whether the Pilot study can be performed <br /> without substantial impact to the local environment, the program could be initiated within 30 <br /> days. <br />