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The quarry is located on the northern side of the Arkansas River. The CKD is currently disposed <br />of in previously mined sections (cuts) of the limestone quarry. The location of cuts previously <br />used for CKD disposal is indicated on Figure 2. CKD is currently being disposed in the cut <br />adjacent to (to the south of) monitoring well MW-10. The bottoms of these cuts coincide with the <br />top of the underlying Codell sandstone, which is the primary water-bearing unit in the quarry <br />azea. To prevent contact of CKD with regional groundwater, approximately 10 feet of shale is <br />backfiiled and compacted in the bottom of these cuts prior to placement of CKD. Descriptions of <br />the site geology and hydrogeology are provided in the Groundwater Monitoring Plan (BBL, <br />2002). <br />On July 30, 1999 the EPA proposed rules for the management of CKD under RCRA. The <br />proposed rule was published in the Federal Register on August 20, 1999 and comments were <br />accepted until February 18, 2000. These proposed rules included technical standards for the <br />management of CKD. In Colorado, the regulatory responsibility for the new requirements has <br />been relegated to the DMG. Therefore, the requirements for CKD management have been <br />incorporated into each facility's Mined Land Reclamation Permit. These requirements include <br />specific requirements for protection of groundwater as described in Rule 3.1.7(7)(1) through (viii) <br />of the "Construction Material Rules and Regulations" (MLRB, 2001) and the Colorado <br />Department of Public Health and Environment (CDPHE), Water Quality Control Commission <br />(WQCC) Regulation No. 41 "Basic Standards for Ground Water" (CDPHE, 2001). <br />Holcim submitted a request for a Technical Revision (TR-06) to its permit on August 16, 1999 <br />for the disposal of CKD in previously mined areas at the quarry (K-S & Company, 1999). TR-06 <br />included a description of CKD disposal procedures and facilities, a closure plan for the disposal <br />areas, a description of erosion control measures used at the site, a discussion of CKD sampling <br />and ana{ysis, and a description of hydrogeologic conditions at the site. The DMG reviewed TR- <br />06 and responded with an initial adequacy review letter on January 18, 2000 (DMG, 2000). On <br />behalf of Holcim, K-S & Company submitted responses to DMG's adequacy review letter in May <br />2001 (Holnam, 2001). The DMG responded with a second adequacy review letter on October 22, <br />2002 (DMG, 2002). The GMP partially fulfilled requirements from DMG's first and second <br />adequacy reviews. <br />1:Violcim\GW Monitoring Report\94332186.doc 1-2 <br />