Laserfiche WebLink
' 1.4 Problem Definition/Background <br /> Varra Companies has submitted a proposal to reclaim approximately 1 I acres of a mined out, <br /> flooded gravel quarry using coal ash as fill material. Numerous permits have been submitted <br /> proposing bench scale testing followed by a small scale field study to evaluate the economic and <br /> ' technical feasibility of using coal ash as fill material in saturated conditions. The proposed Feld <br /> study consists of placing 400 tons of coal ash (fly ash and bottom ash) below the water table at the <br /> Varra gravel quarry in Weld County,Colorado <br /> Four different leaching experiments were conducted in order to evaluate coal ash leaching <br /> potentials. Two of the leaching experiments compared element and compound water quality for <br /> different pH ranges relative to effluent pore volume. However, the data generated from the different <br /> ' leaching tests were not comparable to each other or to water quality standards. It was recommended <br /> by various member of the Colorado Department of Public Health and Environment (CDPH&E) that <br /> additional leaching tests be performed that would simulate, to the extent possible, conditions that <br /> ' would be encountered at the Varra property. <br /> 1.5 Intended Usage of Data <br /> CGRS will use the data obtained in a variety of ways. The major applications of data are: <br /> Health and Safety— Data are used to determine concentration of chemicals to which workers will be <br /> or are being exposed. <br /> Site Characterization —Data are used to determine local physical and chemical properties of soil and <br /> water at the Varra property. Samples of soils, surface and ground water will be analyzed in the field <br /> ' using portable or transportable instruments or sent to the laboratory for certified chemical analyses. <br /> Soil/Ash Interaction — Data obtained from the column studies will be used to evaluate possible <br /> ' affects coal ash may have on natural waters as placed in a permeable environment. <br /> Risk Assessment — Data are used to calculate the effects of target analytes upon human health and <br /> ' other environmental receptors. <br /> 1.6 Project Task/Description <br /> The purpose of this leaching experiment is to simulate, to the extent possible, the effects of coal ash <br /> on water quality when placed in a saturated gravel mine quarry. The experiment is being conducted <br /> as part of several permit submittals to conduct a pilot feasibility study (field study) as mention <br /> above. <br /> ' The leaching experiment will be a modification of ASTM D4874-95 for determining inorganic <br /> concentrations that would potentially leach from a column apparatus. In this study the column will <br /> ' be filled with fly ash and native soil, as would be encountered in the proposed pilot project. The <br /> purpose of the leaching experiment is to simulate, to the extent possible, the interaction of the fly <br /> ash placed in contact with the native material at the Varra test site under saturated conditions. <br /> ' Water obtained from the Varra quarry will be used as the leaching medium and fluorescein will be <br /> added to the water as a visual aid in the experiment. <br /> The scope of work for this project involves, development of Health and Safety and site-specific <br /> ' work plans, field investigations, laboratory analysis of water samples, analysis of hydraulic and <br /> hydrogeologic properties,and the preparation of a report detailing the results of the investigation. <br /> Varra Companies <br /> Quality Assurance Project Plan <br /> Page 2 <br />