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I <br /> <br /> extremely low. There is a lack of faulting in the area of C-Pit. These <br /> factors create a favorable CKD storage environment. <br /> <br /> 7. The testing, modeling and interpretation used in this research was very <br /> conservtive (i.e. worst case scenarios). <br />r <br />Jf <br /> - The model used the concentrated leachate from laboratory tests <br /> not the much less concentrated water in the pit. <br /> - The model assumed the shale adjacent to C-Pit is saturated, <br /> which it is not <br /> - The mode! used conservative attenuation factors <br />- The SPLP laboratory test is aggressive in that the CKD was <br />ground up, mixed with a water solution having a lower pH than <br />natural waters, and agitated for 24 hours. <br />- e wa er ux ra a i.e. amoun o wa er passing t rough the CKI <br />in C-Pit) that was used in the model was conservative. <br />8. Southdown's management practice of periodically capping the <br />disposed CKD with a layer of compacted shale or clay soils would <br />further isolate the CKD from precipitation and infiltration of rain and <br />snowmelt. Southdown has committed to doing this in cells that are <br />built to 7 acres in size and in approximately 20 ft. lifts. <br />2.0 Introduction and Regulatory Background <br />Southdown, Inc. and its predecessors have operated a cement plant and <br />associated quarries in Boulder County near Lyons since about 1969. Cement <br />kiln dust (CKD), baghouse dust, and plant clean-up dust have been managed in <br />the quarries since the inception of the cement plant. There are no known <br />adverse impacts to groundwater from this historic practice. <br /> The quarries south of the cement plant (referred to as the Lyons quarries) <br /> received a 112 permit for the Colorado Mined Land Reclamation Board in 1977. <br /> (Permit No. M-77-208). The permit is active and in good standing, the financial <br /> warranty is in place, and the facility is in compliance with the CMLRB permit. <br /> There are currently over 300 acres under active reclamation. Waste materials <br /> generated at a permitted mine site (the cement plant is within the permit area) <br /> may be disposed at the mine site without a Certificate of Designation pursuant to <br />. the requirements of the Colorado Department of Public Health and the <br /> Environment (CDPHE). Disposal of the CKD in the quarries is in compliance with <br />I the requirements of both the Division of Minerals and Geology (DMG) and the <br /> CDPHE. <br />On January 20, 1999 Carl Mount and Christina Kamnikar of the DMG inspected <br />the facility. The inspection report requested a characterization of the chemical <br />constituents of the CKD, a characterization of the local geology and hydrology, <br />~~ <br />