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Memo to File No. M-77-348 • 2 • October 27. 1998 <br />6. Include in the technical revision a Tinal closure plan for the CKD disposal sites. The clcsure plan would <br />describe capping or covering, revegetation, and post closure ground wafer monitoring. <br />The Operator has provided an application for a technical revision (TR-03) for the disposal of kiln dust in water <br />filled quarry pits. The following list of issues pertain to the hydrogeologic characterization study required in item <br />no. 2 of the above list, and details the shortfalls of the existing hydrogeologic data as provided in TR-03. It is the <br />Division's understanding that Holnam is conducting additional site investigations at both of their r:ement plants in <br />Colorado to facilitate permitting for future CKD disposal under the existing site reclamation I~ermits. These <br />investigations will be useful in addressing the missing information detailed in the following list. It remains to be <br />decided whether the pending TR-03 will be the vehicle used in the permitting process, or if it would be expedient <br />to start over with a fresh technical revision submittal. <br />A component of the rationale for the CKD disposal plan proposed in TR-03 includes permeability data <br />for the strata in the quarry highwall, which is the Niobrara Formation. These data were generated by <br />measurement of the porosity of three rock samples and correlation of the porosity H~ith permeability <br />from a published table. No actual permeability measurements were made, and no evaluation of <br />secondary permeability, i.e., the permeability of the rock mass via fracture flow, was pr~wided. Amore <br />rigorous approach to the evaluation of the highwall formation permeability would have to be completed <br />for the Division to approve CKD disposal in these quarries. <br />2. The technical revision TR-03 application also includes permeability data for the quarry floor formation, <br />which is the Codell sandstone. It is not clear from the information provided what test methods were <br />employed to obtain the permeability values presented. Also, no evaluation of secondar/ permeability is <br />provided. <br />3. It is stated in the TR-03 application that no seepage of the water pooled in the A-Band cut has been <br />observed in the E-Band quarry which has been in operation for several years and i:; down dip and <br />topographically below the A-Band cut. This is presented as further evidence of the impermeability of <br />the formations. However, it must be noted that the E-Band is stratigraphically above the A-Band, and <br />for any seepage from the A-Band pools to flow to the E-Band quarry, it would have to tnavel through the <br />intervening strata including numerous shale beds. The lack of seepage into the E-Band quarry cannot <br />be interpreted to rule out ground water flow down dip from the A-Band cut, nor can it tie interpreted to <br />completely rule out flow paths across the strata. Rather, the lack of seepage into the E-Band Quarry is <br />only an indication that there are no rapid flow paths connecting the A-Band and E-Band quarries. <br />4. Borehole information is provided in technical revision TR-03 demonstrating a lack intc:rconnectivity of <br />the fractures in the Niobrara Formation and the Codell sandstone. The evidence provided is <br />compelling and tends to fill in the information gap regarding secondary permeability discussed in items <br />numbered one and two above. However, the study conducted was clearly not extensive enough to rule <br />out any significant ground water slow paths through fractures. This position is echoed in the excerpts <br />from the April 1990 "Report of Groundwater, Subsurface, and Sediment Investigations" prepared by <br />Stewart Environmental Consultants (SEC) and included with the TR-03 application. It is stated in this <br />report that the "joint structure of the formation is unknown." It is further stated that "(a)lthough the <br />jointing does not appear to be continuous, any continuous joints could be an avenue for contaminant <br />migration." And that "until more conclusive data are obtained on the geology, SEC does not <br />recommend considering the site as a landfill" <br />The following is a list of other issues to be addressed in the process of permitting for the dispos;31 of CKD in the <br />Boettcher Quarry: <br />